GIFT OF PRESS 5-7 MODERN GAS AND OIL ENGINES. By Albert Spies. 'AS engines, at the pres- ent day, are common enough, the past ten or twelve years having wit- nessed the production of a host of designs, al- though of these probably by far the larger number have gained little more publicity than that afford- ed by the patent; office records of different coun- tries. But the more for- tunate ones, those that have been put into mar- ketable shape and sold for a variety of motive power purposes, have been sufficient to amply advertise this type of motor and to practically demonstrate its applicability to many, if not all, the uses to which the steam engine has hitherto been put. It would, therefore, seem almost unnecessary to more speci- fically define it as an engine in which the working fluid is an inflammable gas, or, more correctly, a mixture of atmos- pheric air and inflammable gas, intro- duced directly into the engine cylinder and there ignited and burned. All gas engines, while they may differ widely in theory of action and mechanical con- struction, possess in common this one feature of heating the working fluid in their cylinders proper. Compared with the steam engine as a familiar example, and with most hot air engines, we thus find in the gas engine relative simplicity in so far as no separate fur- nace is necessary in which to burn the fuel from which the energy is primarily derived ; furthermore, the energy is available at exactly the moment needed, and there is no storing up of heat in the same sense as in the steam engine and boiler combination. Hence, it will be seen that the gas engine also has a special applicability in all cases where continuous work is not required. Concerning the origin of the gas engine there is no definite information. By some it has been dated as far back as the latter part of the seventeenth century when gunpowder was proposed and used for obtaining motive power in special apparatus. These early engines, however, can scarcely be properly classed as gas engines. The first gas engine, in the now accepted sense of the term, was probably that patented in the year 1791, in England, by one John Barber. It provided for the use of coal, wood, oil or any combustible in a retort, the generation of vapor or gas from such combustible, and the collection and cooling of the gas in a reservoir. Thence the gas was taken to a compressor which supplied the motor cylinder, and in this latter the gas was mixed with atmospheric air in proper proportion, and exploded by a light. This engine embodied, in the main, the principle of the modern gas engine. Three years later, in 1794, Thomas Mead and Robert Street both obtained patents in England for gas or vapor engines, Mead proposing to raise the piston in his engine cylinder by the ignition of a gaseous, explosive mixture and to utilize for the down-stroke both the weight of the piston and the partial vacuum formed underneath it. This was, in part, the principle of the much later Otto and Langen engine. Street's engine, on the other hand, partly antic- ipated the also much later hydro- carbon engine of George Brayton, pro- viding, as it did, for the production of motive power by introducing a few drops of spirits of turpentine into the heated bottom of a cylinder. The tur- 34i 464520 342 GASSIER 'S MAGAZINE. pentine was vaporized by the heat, air was mixed with it in sufficient quantity to produce an explosive compound, and a flame was applied to ignite it. The next patents for gas engines were not issued until nearly thirty years later (1823). From that time on they ap- peared at shorter intervals until more recently, when design crowded design in rapid succession, so that now the gas engine patents are numbered by the hundreds. The essential differences be- tween the inventions, however, are not very great. In many cases, in fact, it seems sadly true that the inventors have been satisfied with producing simply some detail by which the orig- chine of simple construction, and very similar in appearance to an ordinary horizontal steam engine. The piston moving, say, from the right to the left drew in a mixture of illuminating gas, or of hydrogen, and air through a slide valve worked by the engine. When a certain quantity of this mixture had en- tered the cylinder, the slide valve shut off the supply and an electric spark from an induction coil kindled the gas and caused an explosion which drove the piston to the other end of its stroke. Arrived there, at the left end, a second slide allowed the products of combus- tion to escape while the fly wheel, by reason of its momentum, went on and FIG. I. PLAN VIEW OF THE ORIGINAL OTTO SLIDE-VALVE ENGINE. inal patents could be avoided, rather than anything which really marked a step in advance. It would be impracticable to here follow the history of the gas engine in anything like detail from its earliest days to the time when it became justly looked upon as a distinctly practical and useful source of power. A few of the types, however, which, though com- paratively crude and more or less im- perfect, still came into somewhat ex- tended use and practically opened up the era of commercially successful gas engines, deserve mention. The first of these was the Lenoir engine, made even at this date in a modified form,' a ma- moved the piston in the opposite direc- tion, from left to right. While it moved in this direction, the explosive mixture again entered and was ignited as before, and the piston completed its travel to the right under the impulse of this second explosion. The action, it will be seen, was thus very similar to that of the ordinary, familiar steam engine. To prevent overheating of the cylinder and piston, the former was surrounded with a jacket filled \vith cold water. Following the Lenoir engine came that of Hugon, in which the tendency to become overheated was counteracted by introducing into the cylinder, to- gether with the gas and air mixture, a MODERN GAS AND OIL ENGINES. 343 quantity of water which, in vaporizing, absorbed considerable heat and thus kept the temperature within a reason- able limit. The expansive force of the gases was in this way, it is true, some- what diminished, but the moving parts suffered less, and the engine required less repair and was more durable. Igni- tion of the explosive charge was effected by a gas jet. A number of years after the bringing out of both these engines, Otto and Langen together entered the gas engine field with what they termed their atmos- motor cylinder took its supply from the receiver, but the mixture was ignited as it entered, a grating arrangement pre- venting the flame from passing back. The mixture proper, in fact, did not enter the motor cylinder at all ; what entered it was a continuous flame and the action, therefore, was not explosive in character. At a certain point the supply was cut off, and the piston moved on to the end of its stroke under the influence of the expansion of the hot gases. The flame grating in this engine, however, was a weak point. If by any FIG. 2. THE OTTO GAS ENGINE, BUILT BY SCHLEICHER, SCHUM & CO., PHILADELPHIA, PA. pheric or free piston engine for which they were awarded a gold medal at the Paris Exposition in 1867. The main features of this engine are briefly re- ferred to further on. The Bray ton engine, an American in- vention, was first brought out in 1873. It had two cylinders, one being a com- pressor and the other a motor cylinder. The charge of gas and air was first drawn into the compressor cylinder on the out-stroke, and on the back-stroke was compressed into a receiver. The accident the grating or wire gauze was pierced, in cleaning for example, the flame went back into the receiver and exploded the whole stored-up mixture. Such accidents became so troublesome that Mr. Brayton after a time discon- tinued the use of gas and converted his engine into a petroleum motor. Light petroleum was pumped upon the grat- ing and the compressing cylinder charged the receiver with air alone. The air, in subsequently passing through the grating, carried the petroleum along 344 CASSIER'S MAGAZINE. FIG. 3. OTTO GAS ENGINE AND DYNAMO FOR HOUSE LIGHTING. with it, partly in vapor, and partly in spray form. This oil vapor and air mixture was then ignited just like the previously used gas mixture. The arrangements, in fact, were precisely similar to those of the gas engine, except in the addition of a small oil pump and a slight alteration in the valve disposition. The engine, as may be understood, was single-acting. Right here it should be pointed out that the similarity between the orig- inal Brayton gas engine and the con- verted Brayton engine using petro- leum is typical, also, of all gas and oil engines of the present day. All the oil engines follow the lines of the gas en- gines very closely ; in fact, in some of the gas engines now on the market gas or oil mixtures can be used indiscrimi- MODERN GAS AND OIL ENGINES. 345 nately, the engines working well with either, ^and without modifications of designs to suit the particular kind of fluid used. A distinct classification into oil motors and gas motors cannot, therefore, be well made, and both may be, very appropriately, considered to- gether under practically one head. Broadly speaking, however, the va- rious engines, early and modern, and using either gas or oil mixtures, maybe divided into a few, well-defined types : i. Engines drawing into the working discharging the gas mixture into a re- ceiver or reservoir in a state of compres- sion. From this receiver the mixture enters the motor cylinder, being ignited as it enters. The ignition here does not increase the pressure, but increases the volume. The pump, say, puts one volume or cubic foot into the receiver ; ignition causes it to expand, while enter- ing the cylinder, to two cubic feet. It does the work of two cubic feet in the motor cylinder, so that though there is no increase of pressure, there is never- FIG. 4. OTTO GAS ENGINE AND PUMP COMBINED. cylinder gas or oil vapor and air at atmos- pheric pressure for a portion of the piston stroke, cutting off communication with the outer air, and igniting the mixture. The pressure of the ignited gases pushes the piston forward during the remainder of the stroke, and the in-stroke of the piston expels the products of combus- tion from the cylinder. 2. Engines in which a mixture of gas or oil vapor and air is drawn into a pump forming part of the engine proper, and theless an excess of power over that spent in compression. The return stroke of the piston again expels the products of combustion. 3. Engines in which a mixture of gas or oil vapor and air is compressed, or in- troduced under compression, into the cylinder or space at the end of the cylin- der, and is then ignited, the volume re- maining constant and the pressure rising. Under this pressure the piston moves forward, and on its return as in MODERN GAS AND OIL ENGINES. 347 the previous types, discharges the waste gases from the cylinder. Types i and 3 are explosive engines, the volume of the gas remaining con- stant while the pressure increases. Type 2, on the other hand, is a grad- ual combustion engine in which the pressure is constant while the volume increases. The third type is generally regarded as the best kind of compres- sion gas engine yet introduced, and by far the largest number of gas engines now in every day use are made in ac- cordance with its requirements. The leading idea, compression and ignition at constant volume, was first proposed by Barnett in 1838, and later by several others, but Otto was the first to success- fully apply it in 1876, in the now well- known engine bearing his name. cannon, for example. It is thus shot forward in the cylinder, which is pur- posely made very long. The energy of the explosion gives the piston velo- city, and the piston therefore continues to move considerably after the pressure has fallen by expansion down to atmos- pheric pressure. Owing to this and to the cooling of the gaseous products a partial vacuum is formed behind the piston till its whole energy of motion is absorbed in doing work against the pressure of the outside air. It then stops and the external pressure causes it to perform its return stroke, during which a clutch arrangement connects it with the motor shaft, giving the latter rotary motion. The piston during its return stroke proceeds completely to the bottom of the cylinder, expelling FIG. 6. FIELDING'S GAS ENGINE. SIDE ELEVATION. There still remains one important type of gas engine not included in this classification. It is the kind of engine known as the free piston or atmospheric gas engine already re- ferred to above, and may be regarded as a modification of the first type. The first part of its action is precisely similar ; the latter part differs consider- ably from it. In this engine the piston on moving forward, takes in its charge of gas and air from without at atmos- pheric pressure and temperature. When cut off it is ignited instantaneously, the volume being constant and the pressure increasing. The piston is not connected directly to the motor shaft, but is per- fectly free to move under the influence of the explosion, like a projectile in a the products of combustion. This kind of engine was first proposed in 1854 by Barsanti and Matteucci, but Otto and Langen, as previously mentioned, in 1866, were first successful in overcom- ing the practical difficulties in its way, and many engines were built by them for practical uses. The engine though cumbersome and noisy, was a good and economical worker, and many are prob- ably still in operation to-day. It is scarcely within the province ot this article to take up the theoretical considerations presented by these repre- sentative types of gas engines. Suffice it to say that the causes of the com- parative efficiency of the modern gas engine over the older forms, such as the Lenoir and the Hugon engines may be 348 GASSIER >S MAGAZINE. summed up in the one word " compres- sion." Without compression before ignition an engine could not be pro- duced which would furnish power economically and with small bulk. To the prospective user of a gas engine, the question of cost of opera- tion, or more specifically the cost of fuel used for a given amount of power is, as might naturally be expected, one of the first to present itself. That the fuel or gas cost is unduly great has been, and is still, a more or less prevalent impression and the fact seems to have been largely lost sight of by many power users that the development of the gas engine from what was at first per- haps little more than an interesting driving electric light dynamos, esti- mated that the steam engines in ques- tion would, in a competition, consume about four pounds of coal per indicated horse-power per hour, but that in ordinary work their consumption would run up to six and seven pounds. As- suming a four-pound basis, however, which seems pretty fair, and taking, for the sake of illustration, the price of coal as $5 per ton, we get for the cost of a horse-power for fuel in these engines one cent per hour. At the rate for gas, paid in London at the time, three shillings, or about seventy-five cents per thousand cubic feet, the cost of one horse-power in the gas engine would amount to one and one-half cents FIG. 7 FIELDING'S GAS ENGINE. PLAN VIEW. novelty to a source of even large powers at the present day has naturally brought with it much increased efficiency and correspondingly reduced running ex- penses. Just what these expenses are, so far as they are affected by the items of gas quality and cost, of course depends much upon special circumstances. The price of gas as well as its quality varies with locality and time, and definite state- ments of cost can therefore not easily be given. Professor Ayrton, in England, sev- eral years ago, in comparing the fuel costs of gas engines and of portable and semi-portable steam engines to determine the relative expenses in per hour. Taking the highest prices paid in London for gas, four shillings, or about one dollar per thousand, the gas would cost two cents per horse-power per hour. This makes a very favorable showing for the gas engine, which has so many advantages and economies, as compared with the steam engine, as to easily overbalance its slightly higher fuel cost. In the United States, where the prices for gas are considerably higher, the comparison of the fuel costs would, of course, be somewhat less favorable to the gas engine. Much, however, is to be expected both here and abroad, in the direction of cheaper heating gas, and there seems little MODERN GAS AND OIL ENGINES, 349 FIG. 8 THE DAY GAS ENGINE. MESSRS. LLEWELLIN & JAMES, BRISTOL, ENG. reasonable doubt that such a gas can be made and will probably be made in the near future, and will render the ordinary gas engine up to a certain size, much more economical in running expenses than an equal sized steam engine. Even as it is, however, with gas at the cur- rent rates, the gas engine in a great many cases foots up a smaller expendi- ture for a given horse-power than the steam engine. There is always a very considerable saving when standing still, and this, when the stoppages are frequent, may amount to a most appre- ciable total. As a sample of what may be accom- plished with a cheap heating gas we call to mind a low cost gas enterprise, started a number of years ago in the vicinity of New York City, by which heating gas was made on a large scale under the Strong patents. From figures that were received at the time it ap- peared that this gas had been used in an Otto engine at the rate of thirty-five cubic feet per hour for each horse-power. As the gas was produced at the rate of about twenty-seven cubic feet per pound of coal, it is easily seen that the engine was running on an equivalent of a little less that one and one-third pounds 01 coal per horse-power per hour. At the common retail price, the gas was worth fifty cents per 1000 cubic feet and there was every reason to suppose that the price could be reduced by a large per- 350 CASSIER'S MAGAZINE. centage in the case of a larger plant. Ample evidence was given, however, to show that with the plant in question a great saving over coal was effected, even FIG. 9 THE DAY GAS ENGINE. FRONT SECTIONAL ELEVATION. though it did not produce the gas at the lowest possible rate. In several other cases in England where Otto gas engines were supplied with cheap Dowson gas from Dowson producers specially erected for the pur- pose, it was found on test that the engines consumed on an average the equivalent of 1.2 pounds of coal per indicated horse-power per hour. These results at the time had not a little to do with the subsequent building in England of gas engines of comparatively high powers, double-cylinder engines indi- cating in the neighborhood of seventy horse-power. As to the possibilities of the uses of gas and its future as a source of power, it may not be amiss here to refer finally to one of C. William Siemens' addresses to the British Association for the Ad- vancement of Science in which he ex- pressed the conclusion that if a tem- perature of about 2732 degrees Fahren- heit and a pressure of four atmospheres could be obtained in an explosive gas engine, a theoretical efficiency of about one-half could be obtained, while with a good expansive steam engine the theo- retical efficiency would be about two- sevenths. Deducting the losses by friction and by radiation in both kinds of engine, he held that the best steam engine would yield in mechanical effect about one-seventh of the heat energy, while with the gas engine one-fourth could be easily obtained. As a predic- tion he finally remarked that ' ' before many years we shall find, both in factories and on board ships, engines with a fuel consumption not to exceed one pound of coal per effective horse- power per hour, and with these engines the gas producer will take the place of the steam boiler." This prediction, made a little more than ten years ago, has, as we all know, scarcely yet been fully realized though much progress has been made in the direction outlined, how much, it is, in a measure, our FIG. 10. THE DAY GAS ENGINE. SIDE SECTIONAL ELEVATION. object to show here by an exposition of the various gas and oil engines now in current use, doing a large variety ol work. MODERN GAS AND OIL ENGINES. THE OTTO GAS ENGINE. It seems but rational and proper that we should begin our series of descrip- tions with an account of the Otto engine, or Otto "Silent" engine as it was called in its earlier days, since Mr. Otto, the first to succeed with the free-piston engine, was also the first to succeed in adapting compression in a reliable form, and since, further, it is to the utilization of this compression principle that the gas engine owes its present advanced state of development. The Otto engine belongs to the third type previously referred to, using a gaseous explosive mixture, compressed before ignition, and ignited in a body, so that the press- ure increases while the volume remains constant. The power is obtained by expansion after the increase of pressure. It is interesting to note that the Lenoir and the Hugon engines were practically double-acting, there being two explo- sions for every revolution ; the Bray- ton engine is single-acting, there being one ignition of a charge for every revo- lution ; the Otto engine, however, is what may be termed only half single- acting, there being one explosion for every two revolutions of the engine. The first of several designs of the engine, and one which is still looked upon as the standard form, has a single horizontal, open-ended cylinder. In this works a long trunk piston the front end of which serves as a guide. The cylinder is appreciably longer than the piston stroke, so that the piston, when full in, leaves a considerable space at the end of the cylinder into which it does not enter and which forms a com- pression chamber. Across the back end of the cylinder works a slide valve, con- troll,ing the admission and explosion of the charge, and held in place by a cover plate and strong, spiral springs. The valve is worked back and forth by a small crank on the end of a shaft parallel to the cylinder axis, and rotating at half the speed of the main crank shaft from which it receives its motion by bevel gearing. An exhaust valve and govern- ing gear are also worked from this sec- ondary shaft. The engine cylinder serves alternately the purposes of motor and pump. Dur- ing the first forward stroke of the piston, the admission valve is in such position that the gas and air mixture streams into the cylinder from the beginning to the end of the stroke ; the return stroke then compresses the mixture into the space at the back end of the cylinder. Meantime the slide valve has moved to another position, first closing the admis- sion port to permit the compression of the charge, and then exposing a cavity in the valve in which there is a gas flame when the compression stroke is completed. The compressed charge is then ignited and under the influence of the resulting explosion the piston again moves forward. This constitutes the motive stroke. At the end of it the exhaust valve opens, and the return stroke drives out the burnt gases. The piston is then again in the position to take in a new charge for the next ex- plosion. The cylinder is water jack- eted. A sectional plan of the original Otto engine is given in Fig. i. In this A is the cylinder ; B, the piston ; C, the compression chamber ; the admission port shown extending through the cyl- inder head communicates alternately with the gas and air admission port E, and the flame port F, both of which are in the slide valve G. The latter, as already explained, is held in place by the cover) in which is carried the ignit- ing jet R. The exhaust valve, which is a lift valve with a conical seat, is at K and is driven by the geared shaft M through a cam and lever, N and P. The main slide valve is also driven from this shaft in the manner clearly shown in the illustration. The governor with which the engine is provided is so arranged that when the speed goes above the normal rate it acts on a cam controlling the main gas supply valve and prevents its opening when the piston is drawing in air. To start the engine the igniting jet at R should be lighted, the gas supply turned on, and a few turns be given to the fly-wheel by hand. In some of the later types ol Otto engine the admission slide valve G is replaced by a poppet valve design, 352 CASSIER'S MAGAZINE. Fig. 2 showing one of the modern styles of larger size, indicating about sixty-five horse-power. In this later design, the igniting jet used in the earlier form of engine for exploding the gas charge has also given way to what is known as a tube igniter, or hot tube. This, as its name implies, is simply a wrought iron tube of small diameter, closed at one end. The open end is made to communicate with the engine cylinder by the valve arrangement. The tube is heated by a Bunsen gas flame within a non-conducting casing to prevent loss of heat, and the explosive gas mixture from the cylinder, entering the heated tube under pressure, be- comes ignited. This method of ignition is at once simple and effective. The tube, moreover, is inexpensive and can be easily renewed when necessary. The almost infinite variety of uses to which the engine may be put, and for some of which special designs are turned out, will not admit detailing here and we must content ourselves with the few examples shown. Thus, Fig. 3 shows a modern Otto engine applied to elec- tric lighting, the sizes for this work ranging from fifty to 100 horse-power. Fig. 4 shows an engine and pump com- bination of the latest design in which gear wheels for driving the pump, as first used, have been entirely displaced by belting and correspondingly quiet running has been secured. Double- cylinder and vertical Otto engines are also on the market, all having their legitimate field of use. THE OTTO GASOLINE ENGINE. The poppet valve design has been adopted also in the Otto gasoline engine which has been on the market only a few years. This engine, like all oil engines, can be used where gas is not available, an advantage which has much to commend it and which in a measure explains the impulse which has been given to the oil engine industry during the past few years. In appearance and action the Otto gasoline engine is prac- tically similar to the Otto gas engine, embodying as it does, only some minor valve modifications, and Fig. 2 may, therefore, be taken to represent it as well as its gas ally. In this engine the gasoline is supplied from a tank which may be located out- side the building, through a galvanized iron pipe with soldered joints, and provisions are made against any possible leak of the oil between engine and tank, or after it has reached the engine. The gasoline flows to the admission valve on the engine cylinder by gravity, and on being atomized or sprayed with- in the cylinder by a current of air, is at once fired either by an electric spark or by a tube igniter. Safety con- siderations may make the electric igni- tion method the preferable one, and this is therefore generally used. While the gasoline engine can be used everywhere, and is not limited to exclusive use outside of cities because of possible gasoline vapor dangers, still the largest number of these engines have been placed in manufacturing suburbs not reached by city gas, and in the country. Like the gas engines, they are turned out in various designs for various kinds of work, and gasoline mining engines, electric light engines, portable engines mounted on trucks, etc., are now not uncommon. Messrs. Schleicher, Schumm & Co., of Philadelphia, Pa., are the builders of both the Otto gas and the gasoline engines in the United States, the sizes of both types ranging from one-third horse-power upward. In England the Otto engine is made by Messrs. Cross- ley Bros., of Manchester, to whose de- sign reference will be made in a future issue. THE FIELDING GAS ENGINE. The Fielding engine is made by an English firm, Messrs. Fielding & Platt, of Gloucester, the accompanying illus- trations, Figs. 5, 6 and 7, showing one recently built and capable of indicating 100 horse-power at a speed of 160 revo- lutions per minute. The engine works upon what has become generally known as the Otto cycle referred to in the just- given description of the Otto engine as well as somewhat earlier in this article ; but the arrangement of the valve gear embodies some new features. Fig. 5 MODERN GAS AND OIL ENGINES. 353 gives a general view of the engine, while Figs. 6 and 7 show an elevation and a plan respectively. The working charge is admitted and the waste products exhausted by means of a simple mitre-seated valve, through inlet and outlet ports controlled by the movements of a piston valve which re- ceives independent motion from an eccentric, which also operates the timed ignition valve. The valves are placed The importance of a starting gear for engines of such large size which cannot easily be turned over by hand is at once apparent, and due account has been taken of it in this engine by the pro- vision of a new form of such gear patented by Mr. Fielding. This gear comprises a small reservoir of about the size of the cylinder jacket, which, after the engine has once been started, is charged with compressed air at a press- FIG. II. THE GRIFFIN OIL ENGINE, CONSTRUCTED BY MESSRS. GRIFFIN & CO., BATH, ENGLAND. horizontally by the side of the cylinder, an arrangement which permits of very straight and direct pipe connections for gas and exhaust, the air being drawn through the cylinder base, which acts as a muffle. The main mitre- valve is worked from a cam by a rod leading direct to the valve. The governor is of the high-speed, ball type acting upon a hit-and-miss gear interposed between the gas valve and its cam. ure of about fifty pounds per square inch by the engine itself when being stopped, thus utilizing the power stored up in the fly-wheels for use when re-starting the engine. The action of starting is as follows : The engine crank being placed slightly in advance of the dead centre nearest to the cylinder, gas is admitted by a small cock to the combustion chamber, from which the air is allowed to escape at a small pipe provided with 354 CASSIER'S MAGAZINE. a stop-cock and terminating in a jet near the top of the tube igniter. When the air has been driven out and the gas begins to escape at the jet, it becomes ignited, and as soon as it burns with a steady flame, showing that an ample supply of gas is present in the cylinder, the outlet and inlet cocks are closed. Compressed air is then turned into the cylinder, and the igniting valve being open, as soon as an explosive mixture is formed and sufficient pressure attained, the charge is ignited by the igniting tube, and the piston is driven forward with a powerful impulse, the ordinary cycle at once coming into operation. This method of starting is claimed by the builders to be so power- ful that an engine can be started with partial load on, and any arrangement of fast and loose pulleys or friction clutch is thus entirely dispensed with. THE DAY ENGINE. The Day engine, shown in perspec- tive and sectional elevations in Figs. 8, 9 and 10, is built by Messrs. Llewellin & James, of Bristol, England, and appears to have been designed \vith special reference to adaptability to domestic or other uses where the ut- most simplicity and consequent ease of management by unskilled attendants are primary considerations. Few mov- ing parts and an entire absence of what may properly be considered valve gearing are therefore the leading- features of this engine. What moving parts there are besides the piston and fly-wheel are, moreover, completely hidden by a casing, so that the engine is simple in appearance as well as in fact. The crank chamber, as shown, is closed in and as the piston A rises a partial vacuum is formed underneath, and gas and air in proper proportion are drawn in through the passages D. These are controlled by a flap valve on the inside of the crank casing, and when the piston, after having reached the upper end of its stroke, begins to de- scend, this flap valve closes the gas and air inlets, and the completion of the down-stroke causes a slight compres- sion of the explosive mixture in the crank chamber. At the end of the down- stroke a port opening at the side of the cylinder is uncovered by the upper end of the piston and through this the explo- sive mixture rushes into the cylinder proper above. In passing into the cylinder the gases impinge on the fin B on top of the piston and are thus deflected upward, displacing the prod- ucts of combustion of the previously exploded charge, which pass out through the exhaust opening K (Fig. 10). The cylinder now is practically filled with an explosive mixture at at- mospheric pressure. The piston, now again rising, cuts off both the supply and exhaust openings, and the mixture in the cylinder is compressed. When the piston reaches the upper end of its stroke, it drives the gas mixture into an ignition tube, F, and an explosion results. It will be understood from this that there is one explosion for every double stroke or every revolution. A water- jacket keeps the cylinder cool. To start the engine, which obviously is made only in small sizes, it is simply necessary to give a few turns to the fly- wheel by hand. THE GRIFFIN OIL ENGINE. The Griffin oil engine, made by Messrs. Griffin Co., of Bath, Eng- land, works with ordinary petroleum, either such as is used in domestic lamps, or with the cheaper and heavier varieties. This engine, too, w r orks on the four-stroke or Otto cycle. The points of novelty lie principally in the vaporizer, and in the burner for keeping the incandescent firing tube red hot. The vaporizer lies athwart the bed under the cylinder. It is a cast-iron vessel, surrounded with a passage for the emission of hot exhaust products from the cylinder, and pro- vided internally with ribs to increase the heating surface. The oil enters it at one end, that shown in Fig. n, in the form of fine spray, and is drawn out through the curved neck at the opposite end, Fig. 12, into the cylin- der. In their passage the vesicles of oil become converted into vapor by the MODERN GAS AND OIL ENGINES. 355 FIG. 12. THE GRIFFIN OIL ENGINE. heat of the walls, and shortly before the cylinder is reached they are mixed with additional air entering through the box to be seen below the bed. This air also has its temperature somewhat raised, as the inlet and exhaust pas- sages run side by side in the curved end of the vaporizer leading to the cy- linder. The spraying of the oil is effected by air compressed to twelve pounds on the square inch by a pump worked off the side shaft. The oil runs by gravity out of a reservoir in the bed, and is emitted through a fine tube into the air delivery nozzle. The blast picks it up, and, driving it for- ward, atomizes it at once. The flow of oil is regulated by the air jet itself; when the jet is cut off by the governor, the oil ceases to flow. This result is attained by means of a valve on the oil pipe. This valve closes naturally and is only opened by the air pressure ; immediately this is admitted to the pipe the valve lifts and the air flows. The heating of the incandescent tube 317 is accomplished simply and ingeniously. The oil trickles into a tiny box and flows over a weir, which keeps it at a constant height. Two little wire pins stand in the oil at such a distance apart that the liquid creeps up between them by capillary attraction. On to the head of the column so raised, there impinges a fine air blast, which sprays the oil and carries it forward through a pipe to a Bunsen burner playing on the ignition tube. The pipe rapidly becomes heated by conduction from the burner and effects the vaporization of the oil, which burns like a gas jet, without odor. The governor is of the centrifugal type and controls a hit-and-miss device. From this there is worked the admis- sion valve, the exhaust valve, and the air inlet to the vaporizer, all being thrown in and out of action simulta- neously. It is claimed as a feature of importance in the engine that all the valves are at rest when running light and operate only in direct proportion 356 CASSIER'S MAGAZINE. to the work being done, thus saving wear and tear. The vaporizer needs to be heated before the engine is started. A hand lever is supplied by which the air- pump is worked for ten minutes. The air is used to spray the oil, as if the engine were at work, but the jet is ignited as it enters the vaporizer and fills the latter with a powerful flame. A door is opened at the further end of the vaporizer and a temporary deflector fixed on to di- rect the flame under the passage lead- ing to the cylinder. Ten minutes suffice to raise the temperature to the required extent. Up to the present time only small sizes of the engine have been built, but larger designs are under way. ( To be continued. ) THE UNITED STATES PATENT OFFICE. By R. D. O. Smith. 1HAVE just read with interest Mr. Leon Mead's "Influence of Pat- ents on American Industries," and regret that his examination should have been so brief. The cornerstone of our national prosperity is worthy of more exhaustive treatment. In his first paper there are one or two errors which, while not momentous, still ought to be corrected. On page 117 he says: In the year 1812 the Patent Office was removed to a build- ing purchased and repaired for the ac- commodation of the general post- office, and that said building stood on the site of the present post-office de- partment building. Washington was captured by the British in 1814, con- sequently the episode and removal mentioned are placed at a date too early. The building to which the Patent Office was removed was located where the so-called city hall now stands in Judiciary Square and not on the site of the present general post-office. When I went first to Washington in 1857 the city post-office w r as in a rickety old building on Seventh street, on ground now occupied by the general post-office. It had been standing there many more than twenty years. There was saved from the fire of 1836 out of the records of the Patent Office but a single drawing. Patentees were invited to return their letters patent to the commissioner, who had the specifications copied into books and the drawings copied on sheets for the draftsman's room. Many of these re- produced drawings are models of artis- tic excellence. But many patentees neglected to have their patents re-recorded. In fact, I presume but few except those whose patents were still young, or which had proved to be remunerative, responded. A great many who did respond also filed duplicate models. At the fire of 1877 but few, if any, models of pending cases were lost, since models of pending cases are kept in the secret archives of the office, and mostly in the examiner's rooms. The fire did not extend beyond the north and west model rooms on the upper floor. None of the examiners had rooms on that floor at that time, and few, if any, of the paper records were lost. I believe there were some duplicate copies of the printed specifications which were burned, but none of the original records and none of the relics or other me- mentoes which were then preserved in the Patent Office, since all such were kept in the old or South Hall. The two burned model halls were the most spacious, and contained, I presume, MODERN GAS AND OIL ENGINES. By Albert Spies, Mem. Am. Soc. Mech. Eng. i $econd HE fact has already been briefly noted that not a few of the gas en- gines now on the market are adapted as well to the use of gaso- line as to the use of gas proper, and that only a f e w slight modifications of design are sometimes necessary, and are provided for to permit changing from one fluid to the other. Such provision is made in the case of the Otto engine, as described in the preced- ing paper, and also in that of the Caldwell-Charter gas engine, built by the H. W. Caldwell & Son Company, Chicago, 111., and shown in perspective and in sectional elevation, respectively, in Figs. 13 and 14. In both these views the engine is represented as arranged for the use of gasoline. In Fig. 14 A is the working cylinder ; B, the piston ; S MAGAZINE. FIG. 77. DOUBLE FLY-WHEEL "FORWARD" E-NGINE. FIG. 76. THE "FORWARD" ENGINE, BUILT BY T. B. BARKER & co., BIRMINGHAM, ENGLAND. MODERN GAS AND OIL ENGINES. 199 The sprayed oil is converted into vapor in its downward travel through FIG. 78. VERTICAL "FORWARD" ENGINE. ignition tube with a timing valve worked by the lever I and cam O. Compres- sion in the cylinder is diminished by keeping the exhaust open when the engine is being started, and one man can, therefore, easily turn the engine over. The oil used is ordinary lamp oil. From the oil tank A the oil, as just stated, flows to the lower receiver B, and from the latter it passes through the regulator and into the top of the vaporizer E. In this the oil is sprayed by an air current and passes through tubes in the vaporizer, which forms an enlargement of the exhaust pipe. The bottom of the vaporizer is heated by a lamp flame for starting, but after the engine is once in operation the exhaust gases perform the heating. The main air admission pipe is marked F and is provided with a regulating cock, F 1 . Air is also admitted to the vaporizer through the pipe D, which, similarly, has a regulating valve. FIG. 79. LANCHKSTER'S STARTING GEAR. FIG. So. THE HICKS GAS ENGINE, BUILT HICKS GAS ENGINE WORKS, CLEVELAND, BY THE OHIO. 200 CASS/X'S MAGAZINE. FIG. 8l. THE SINTZ ENGINE, KUILT BY THE SINTZ GAS ENGINE COMPANY, GRAND RAPIDS, MICH. the vaporizer, and, in addition to the air of the spraying current, takes in a further supply through the pipe D. It then passes into the pipe issuing from the bottom of the vaporizer and joins the main air inlet pipe at a point above the cock F 1 . From this point it finds its way into the cylinder of the engine through a valve, G, controlled by the governor H, trip P and notch piece N. When the engine runs too fast the spindle of the admission valve G is missed, and another valve, not shown in the illustration, is opened to allow the gas contents of the cylinder to escape. The exhaust valve lever is shown at J ; W and W 1 are water cir- culating pipes for the cylinder jacket, and X is the exhaust pipe. The ig- nition tube is surrounded by a case, K, and L is the oil and air admission pipe for the heating flame. The engine is made in sizes of from one to ten horse- power. (To be continued. ) MODERN GAS AND OIL ENGINES By Albert Spies, Mem. Am. Soc. M. E. $ixth VER since the first practical utilization of gas and oil engines and the satis- factory demonstration of their applicability to general power purposes, builders of such engines have sought to cultivate special fields in which to secure new employment for the motors and, as a consequence, they are found at the present time performing the widest variety of services. Not only as stationary, but also as portable engines, mounted on trucks, for agricultural purposes, as fire engines, pumping engines capable of being rapidly taken from place to place, as locomotive engines driving road carriages, and as marine engines for propelling launches, as instanced re- peatedly in the preceding papers, they are successfully used. In fact, there is no line of work that can be readily called to mind in which they are not now either successfully operated, or to which they do not promise to lend themselves with satisfaction. They are no longer the clattering, noisy engines of early years, nor have they retained the excessive bulk and great weight for even moderate powers which characterized some of them when first brought out ; instead, they have been made surprisingly quiet in operation, and in size and weight have been brought down almost to the figures ruling in steam engine practice, so that, for the same powers, a modern gas or oil engine and an 'average steam engine are not very unlike. Among the many oil engines which probably first became best known in the United States as specially applicable to launch propulsion is the Daimler motor, built in this country by the Daimler Motor Company, of Steinway, Long Island City, N. Y., and intro- duced also in England by Messrs. Sims & Co., of London. The engine is designed for the use of either gas or gasoline, and is the invention of Mr. Gottlieb Daimler, of Cannstatt, Ger- many, who for many years was asso- ciated with the late Dr. Otto. It is by no means, however, restricted to launch use, but is applicable to all the several motor purposes for which the various engines of its class have been employed. Figs. 82 and 83 represent different views of a single-cylinder Daimler motor, while Fig. 84 shows a double- cylinder design, the motor, it being proper to state here, being made with one or more cylinders according to the power required. Thus, while the smaller sizes are of the single and double-cylinder designs here illustrated, the five and ten-horse-power engines have four cylinders placed side by side. The principle of operation, however, and the main features of construction are the same in all the engines. For the purpose of our explanation of the manner of working we will take the single-cylinder engine, the cycle of operations applying equally well to all the others, being simply multiplied in number with the increase in the num- ber of working cylinders. Fig. 87 represents a vertical section of one of the engines along the line of the shaft and clearly illustrates the character of the internal construction, the valve me- chanism, governor connection and other important working details. Within'the 293 294 CASSIER'S MAGAZINE. X R FIG. 52. SINGLE CYLINDER MOTOR, BUILT BY THE DAIMLER MOTOR COMPANY, NEW YORK. base of the motor, which consists of a cast iron circular chamber, are arranged two crank discs, mounted upon the two sections of the main shaft and connected by the crank pin, the crank discs serv- ing also the purpose of fly wheels. In one of the discs is formed a double cam groove which passes twice around the crank-shaft and returns into itself. In this cam groove works a follower, or two followers in the case of a double- cylinder engine (see Fig. 85), operating the exhaust valve gear so as to make every other stroke a working stroke, and thus maintaining the Otto cycle. When two or more cylinders are used, they are arranged either parallel with one another, or they are inclined so as to form a slight angle. In the double- cylinder engine both connecting rods work on the same crank pin, and both pistons, therefore, move up and down together ; but on the down-stroke one of them is always moving under the impulse of an explosion, while the other is drawing a working charge into its cylinder, and on the up-stroke one of them is always expelling the waste gases, while the other is compressing a charge. Ordinarily, therefore, there is in the double-cylinder engine an explo- sion in either one or the other cylinder MODERN GAS AND OIL ENGINES. 295 at every revolution of the crank-shaft. In the engine as arranged for work- ing with gasoline, A (see Fig. 82) is the carburetor ; O is the exhaust pipe which is provided with a perforated casing through which the air is drawn on its way to the carburetor, becomes warmed before it reaches the latter, and is thus better able to become impreg- a platinum ignition tube C. With this ignition tube heated to redness and a few turns given to the engine by means of the crank handle S to draw in the initial working charges, the engine will proceed regularly with its work. A vertical section of the cylinder, valves and crank chamber is given in Fig. 86. The admission valve is held to its seat FIG. 83. SINGLE-CYLINDER DAIMLER MOTOR, WITH COOLING WATER CIRCULATING PUMP. nated with gasoline vapor. From the carburetor the mixture goes through the valve H which also admits an addi- tional air supply through the open-end, curved pipe, shown at the left, and the charge finally reaches the valve chamber. The small valve F regulates the supply of gasoline to the burner D which heats by a spring and opens inward under the influence of the partial vacuum formed in the cylinder by the suction stroke of the piston . The exhaust valve is simi- larly kept closed by a spring while the admission valve is open, and is pushed upward and opened to permit escape of the waste gases from the cylinder at the 296 CASS/EjR'S MAGAZINE. proper time by the exhaust valve rod which is % operated, as previously re- marked, by the follower working in the cam groove in one of the crank discs. The governor arrangement is exceed- ingly neat and simple. The governor, it will be seen, is mounted inside the driving pulley on the crank-shaft, and by means of a sliding collar controls the position of a centrally pivoted rod. When the speed of the engine rises above the normal, the governor weights move charge of explosive mixture can obviously not enter. No impulse can, therefore, take place in the cylinder until the speed has become slower and the exhaust valve rod has been allowed by the governing gear to resume its original position where it can strike the exhaust valve spindle and open the valve. The pipe R, Figs. 82 and 83, is one FIGS. 84 AND 85. PERSPECTIVE VIEW AND ELEVATION OF DOUBLE-CYLINDER DAIMLER MOTOR. outward, carry the sliding collar along the shaft, and deflect the upper end of the pivoted rod which comes in contact with the upper, jointed end of the ex- haust valve rod and turns it to one side. In this position the exhaust valve rod, on its upward stroke, misses the exhaust valve spindle, passing to one side of it, and the exhaust valve consequently is not opened, the waste gases cannot escape from the cylinder, and a new of the water circulating pipes delivering cooling water from a small pump, marked 2, to the jacket Q around the cylinder, another pipe returning the water, which may be used over and over again, to a tank marked i. Where some other source of water supply is available, the tank and pump may, of course, be dis- pensed with. In fact the design shown in Fig. 83 is now but little used. With the pump and tank attachment, however, MODERN GAS AND OIL ENGINES. 297 FIG. 86. A DAIMLER MOTOR LAUNCH. the motor is entirely self-contained and can be used anywhere, without depend- ence upon either gas or water mains. The tank I, Fig. 82, serves for gasoline storage and can be conveniently located, outside of the building if desirable. A float index E on the carburetor A, indicates the level of the gasoline within. When the carburetor is completely charged, the supply will last about five hours. Where the reserve tank I is applicable it will be necessary to charge the outfit only once a day for a running time of ten hours. When gas is avail- able the carburetor and reserve tank naturally are done away with, and the engine assumes a somewhat simpler appearance, as shown, for example, in the illustration of the double-cylinder motor. The single cylinder design is followed for sizes up to one horse-power ; beyond that, two and four cylinders are employed. In the four-cylinder engines, and also in some of the two-cylinder engines as built in Germany, the cam- groove exhaust valve gear as here de- scribed is not used, but in its place a separate cam shaft, driven by gearing from the main shaft is employed. The general features of design and the manner o'f working are, however, exactly the same. When used for boat propulsion, the motor is generally completely boxed in so as to protect it against the weather, and is fitted with a suitable reversing gear. Being of German origin, the engines having first been built by the Daimler Motoren Gesellschaft, of Cannstatt, which is still making them, it is only natural that in Germany and in Europe generally we should find the motor applied most extensively and to the widest variety of uses. At Stuttgart, for example, it is in successful operation in propelling a street car. It has also been applied on some of the German railroads to driving small inspection cars, similar to the familiar hand cars, and has similarly found favor for the propulsion of road carriages, quadricycles and even bicycles, not to mention the large num- ber of pleasure boats which are equipped with it. The English firm of Sims & Company, of London, are actively prose- cuting the introduction of the motor into British territory. 298 GASSIER' S MAGAZINE. Before finally leaving the Daimler motor a little more information concern- ing the carburetor used may not be amiss. A sectional view of it, with some of its accessories is, therefore, given in Fig. 89. The lower part of the appa- ratus consists of a small tank H, con- taining a float B, which rests upon the gasoline. The float is provided with a central funnel which communicates with the main body of the liquid in the tank through a small opening at the bottom, so that while the liquid is maintained at a constant level in the funnel, it is practi- cally isolated from the main body of the petroleum. The float is provided with an air tube entering the funnel, and per- forated below the surface of the gasoline. This air tube slides freely in the tube F, attached to the cover of the apparatus and acting as a guide, allowing the float to rise and fall according to the supply of gasoline. Hot air is admitted to the carburetor through the pipe attached to the upper part of the apparatus, the air being heated in its passage to the car- buretor by the products of combustion as already explained in describing the engine proper. The carbureted air passes through the vapor pipe in the direction indicated by the arrow, and unites with a stream of air drawn into the motor cylinder through the admission valve at G. This valve is provided with a graduated scale which facilitates the adjustment. It has also an automati- cally operating safety valve. The reser- voir is filled through a supply pipe extending down to the bottom through the air tubes and float. The supply pipe communicates with the lamp font p, which furnishes the oil to the burner, by means of which the ignition tube is heated. The time required for heating the latter and starting the motor is in- appreciable. The motor may be stopped temporarily by shutting off the supply of combustible gas, allowing the ignition tube burner to continue burning. For a complete stop, however, the ignition tube burner is extinguished in addition to shutting off the gas. One of the most interesting and in- geniously designed gas engines put on the market by English makers is the Atkinson differential engine, first brought out eight or nine years ago by the British Gas Engine & Engineering Company, of London. The main object FIG. Sj. SECTION OF DAIMLER MOTOR. sought after in this engine was to allow the exploded charge to expand much more rapidly than is usual or possible in most other gas engines, and to thus be in contact with the relatively cold cylin- MODERN GAS AND OIL ENGINES. 299 der walls for a shorter period of time. In this way, it was agreed, an important economical end is served. The engine in its earliest form is shown diagrammatically in Figs. 91 to 94, from which the main peculiarities of its opera- tions will be more clearly understood. The cylinder in this early design was open at each end and had two piston^ connected by curved levers and short connecting rods to one crank pin. The through a port in the cylinder wall. The crank pin was, at this time, on the left, and as it proceeded upward and around to the right, the left-hand piston moved rapidly away from the other, leaving a space between them into which the gas and air mixture was drawn through a self-acting suction valve. When the crank pin had reached its highest posi- tion, as in Fig. 92, the right-hand piston traveled past and closed the openings to FIG. 88. QUADRICYCLE PROPELLED BY A DAIMLER MOTOF. pistons both traveled in the same direc- tion but at very different speeds. When at the outer end of their stroke, they remained almost at rest for nearly half a revolution of the crank pin, but when at the inner end of the stroke they traveled rapidly. When the pistons had com- pleted a stroke to the right, as in Fig. 91, they almost touched each other, and had driven out the products of combus- tion of the previous working stroke the suction and exhaust valves, and during the next quarter turn the pistons again approached each other, compress- ing the explosive charge between them, the crank pin by that time being'overat the right-hand side, as in Fig. 93. At the moment of greatest compression, the left-hand piston passed an opening to an ignition tube which produced explosion of the charge, and an immediate, rapid stroke was made by the right-hand 3 oo CASSIER'S MAGAZINE. piston and was completed by the time the crank pin arrived at the lower quarter, as in Fig. 94. The exhaust port was then opened by the continued travel of the piston, and the contents of the cylinder were driven out through the self-acting exhaust valve by the left- hand piston which assumed the position shown in Fig. 91, the whole cycle being- cylinder becomes very low. It will also be observed that the total expansion to twice the original volume took place in a quarter revolution of the crank-shaft as compared with other gas engines and this expansion to double the original volume was accomplished in one-fourth of the time taken for the same degree ot expansion in other engines, assuming FIG. 9. SECTIONAL VIEW OF THE CARBURETOR USED WITH THE DAIMLER MOTOR. completed in one revolution of the crank- shaft. The space between the pistons into which the ignited charge expanded was nearly double the space into which the charge was first drawn previous to ex- plosion ; consequently, the expansion amounted to nearly twice the original volume, and the terminal pressure at which the gases were expelled from the the engine to run at the same speed. The economy to be gained from the extra expansion is obvious, while the saving due to the rapid motion of the piston is also beyond question, having been conclusively demonstrated experi- mentally by a French authority, Pro- fessor Witz, a number of years ago. Without going in detail into the experiments made by him, it may not MODERN GAS AND OIL ENGINES. 301 FIG. 90.- -ATKINSON'S MODERN GAS ENGINE AND AIR COMPRESSOR COMBINED. be uninteresting to here briefly state that in one series of experiments he used a mixture of one volume of illumi- nating gas and 6. 33 volumes of air a not unusual proportion for gas engines. This mixture was drawn into an experi- mental cylinder and exploded, the piston being allowed to travel at the rate of i . 7 meters per second, corresponding to an ordinary piston speed in a medium- sized gas engine. The actual amount of work done was estimated from a diagram obtained from the cylinder. He then increased the speed of the piston, and found that by allowing the piston to move at the rate of 4. 3 meters per second, or 2.54 times as fast as before, the same amount of gas did 2.9 times as much actual work. This large increase is chiefly due to the fact that the heat of combustion of the gaseous mixture is, at the higher speed, not allowed to continue so long in contact with the walls of the cylinder which are kept cool by the customary water jacket. It has been held that more than one- half of the total heat in the gas, even if thoroughly consumed, is lost by trans- mission to the water. If then the work is done in one-fourth of the time, as in the Atkinson engine, three-fourths of this serious Joss must be saved, since the transmission of heat through metallic substances is directly proportionate to the length of time that the differences of temperature exist ; hence, the great increase of power shown by Professor Witz's experiments. The engine in its early form was ex- tremely simple. There were no slide- valves, nor were there any complicated substitutes, the working charge being efficiently controlled by the pistons passing the ports to the two self-acting valves and the port to the ignition tube. There were also neither cams nor eccentrics. In the course of the last few years, however, the design of the engine has undergone some changes, so that at the present time its appearance is like that shown on this page. The ' ' Utilite ' ' gas engine, built by the same firm, was not designed as a rival to their standard engine, but 302 CASSIER'S MAGAZINE. simply as an alternative motor for obtaining practically the same results and, to a certain extent, to meet the varied views of buyers of gas engines. Perhaps the most distinctive feature of this later engine is found in the fact that the crank end is cased in and the space thus afforded is used as an air chamber whose supply serves to flush out the cylinder after each working stroke, the waste gases being allowed to escape through an opening in the side of the cylinder uncovered by the piston in its travel. There is thus no exhaust valve of the usual kind. After the flushing of the cylinder has taken place, a small charging pump delivers into the firing end of the cylinder a rich mixture of fresh gas and air, the air proportion, however, being insufficient to permit explosion until it has been further added to. The piston, after having made a working stroke, returns and is allowed to expel through the exhaust opening some of the cylinder contents which, at the piston end of the cylinder, are made up of waste products of combustion or, per- haps, simply air. At about half the return stroke, however, the piston closes the exhaust opening or port, and what then remains in the cylinder is air and gaseous mixture in more or less defi- nitely separate layers, the gas mixture being in the firing end of the cylinder, and the air alone, in the piston end. As compression takes place, the air and gas and air mixture become more inti- mately mixed and by the time the cylinder contents are fully compressed they are in a proper condition for ignition which then takes place ; a working stroke is made in this manner once for every revolution of the crank-shaft. A small valve, in addition to the exhaust opening in the cylinder wall, controlled by an eccentric, allows a portion of the air to be removed from the cylinder before the compression stroke is completed, so as to leave only about one-half the original cylinder con- tents shut up, which, after compression and ignition, is allowed to expand to double its original volume. As a result, the diagram from the engine is prac- tically the same as the diagram from the regular Atkinson engine, and the economy of the two is claimed to be practically the same. It is further claimed for the " Utilite " engines that they combine great lightness with rigidity and that they can be run at very high speeds without heavy foundations and without causing any trouble from excessive vibration. Speeds as high as 600 revolutions per minute are claimed to have been maintained with good re- sults. One of the later types of vertical gas FIG. 92. FIG. 93 FIG. 94. DIAGRAMS OF THE ATKINSON DIFFERENTIAL KNGINE. engines is that made by the Hartig Standard Gas Engine Company, of Brooklyn, N. Y., both single and double fly-wheel designs being shown in Figs. 95 and 96. There are, in all, four valves in this engine, a governor valve, automatically controlling the gas supply according to the amount of po\ver re- quired, a lighting valve, a gas and air admission valve, and an exhaust valve. The governor valve is in the main gas supply pipe and is worked by the verti- cal rod sho\vn at the extreme left of Fig. 95. The governor itself is of the shaft type, the centrifugal force of the two weights being restrained by springs attached to the weight arms and to the MODERN GAS AND OIL ENGINES. 303 weights in the manner indicated. With increase in speed above the normal, the weights move outward, and revolve a cam, mounted on the crank-shaft and provided with a helical groove and pin arrangement which causes the cam to slide in and out along the line of the shaft. When moved inward, that is, a decrease in speed. With the lower speed the governor weights return to their original position, the cams are thrown out of contact, and the gas supply valve is again opened. The exhaust valve is worked by the rod shown furthest to the right in the engraving, and receives motion from the FIG. 95. THE HARTIG ENGINE, BUILT BY THE HARTIG STANDARD GAS ENGINE COMPANY, BROOKLYN, N. Y. from left to right in the engraving, the cam comes in contact with another and smaller cam, directly connected with the main gas valve rod, and causes the valve to close more or less, thus shutting oft the gas supply or simply reducing its volume, and consequently bringing about crank through the intervention of two gear wheels, one of which has twice the diameter of the other. The valve is thus opened once in every two revolu- tions, the engine working on the Otto cycle. The valve rod connects with a valve lifting arm pivoted at one end, 304 CASSIER'S MAGAZINE. and, in its upward motion striking the valve spindle from below and lift- ing the valve from its seat to which, ordinarily, it is held by a spring. The igniting valve at the front of the engine is operated by a rod connected with a rock shaft, mounted on the engine frame as clearly shown, and re- ceiving motion from the crank shaft tial vacuum formed in the engine cylin- der during the suction stroke of the piston, and closes of its own accord during the compression period, remain- ing also closed, for obvious reasons, during the working and exhaust strokes. The valves all are of the lift type, insur- ing lightness and freedom from sticking and clogging. The engine is made in FIG. 96. HARTIG DOUBLE FLY-WHEEL ENGINE. through a rocker arm and cam gearing. The igniting gas jet burns at the side ot this valve and, at the moment of valve opening, communicates with the explo- sive mixture in the cylinder and fires it. The gas and air admission valve, located almost directly behind the igniting valve, is not worked by any rod or gearing, but opens under the influence of the par- sizes of from one to eight horse-power, though a small half horse - power pump and engine combination is also turned out. Experience with this engine has shown that it is well adapted to the driving of electric light dynamos, and it is for this work that its builders' make one of their strongest claims, being specially pre- MODERN GAS AND OIL ENGINES. 305 FIG. 97. THREE CYLINDER "TRUSTY" OIL ENGINE AT THE WORLD'S FAIR. pared to furnish gas driven, isolated electric light plant outfits. A petroleum engine in which the now so widely used Otto cycle is not followed is that built by Messrs. Penney & Co., of Lincoln, England, and known as the Weatherhogg engine. In this a prac- tical application is made of the six-stroke cycle, already referred to in one of the preceding papers, a scavenger charge of air being taken into and discharged from the cylinder during the interval between exhaust of the products of com- bustion and the admission of the work- ing charge. The oil is injected into a vaporizer by a pump, which acts only when the speed 5-22 of the engine is normal or less,' being operated by a hit-and-miss device con- trolled by the governor. The oil is delivered into a coil heated by a blow- pipe flame, and is there vaporized under pressure. The flame is produced from a spray of petroleum, and is fed by compressed air from a pump, which can be worked by hand at starting. When starting the engine, a handle is fixed to the crank which works the pump, and it is rotated by hand for a few minutes, until the coil is hot. The oil is then injected and the vapor is allowed to accumulate until it attains a considerable pressure, which is main- tained during working. It is claimed CASSIER'S MAGAZINE. that better results are obtained by this pressure, and that it enables crude petroleum to be used if required. The pressure can be regulated by adjusting a throttling device at the outlet of the vaporizer. Between the vaporizer and the cylinder is the air admission valve, contained in a box in which mixture of the charges take place, ignition being effected by a heated tube. In some cases a part of the air is taken from a box in which the crank and connecting- rod are inclosed, and in this Way any leakage past the piston is caught and prevented from escaping into the engine room. In connection with the ' ' Trusty ' ' double-cylinder oil engine shown in the June number, it is of interest to direct attention to a 'vertical, three-cylinder oil engine built by the same firm, Messrs. Weyman & Hitchcock, of Guildford, England, and shown at the World's Fair at Chicago. The principle of oper- ation is essentially the same as that of the engine already described. The three cylinders are connected to a three-throw crank shaft, with the cranks set at angles of 120 degrees, so that the work of the cylinders is well distributed throughout the period of each revolu- tion. The valve gear is worked from a cam shaft driven by worm gearing, but each cylinder has its separate cams so that any one of them may be cut out at will. ( To be continued '. MODERN GAS AND OIL ENGINES By Albert Spies, Mem. Am. Soc. M E. $eventh | HE methods of ig- niting the working charges in gas and oil engines are de- tails of design to which considerable study has been given without, however, having brought about anything like uniformity of prac- tice. No one partic- ular device, as was to be expected, has been centered upon as the best or most desirable one, and recurrence to the descriptions of engines already given in the preceding papers will show that electric ignition, flame ig- nition and ignition by incandescence all have found a share of favor in the eyes of gas engine builders. Electric igni- tion has been practiced either by the spark method, as in the early Lenoir engine, in which, at the proper times, an electric spark was made to pass between two electrodes within the cyl- inder, or by the incandescent wire method, in which an electric current was applied directly to heat a thin plat- inum wire. This latter method would appear to have been used only in an ex- perimental way. Still another electric arrangement has been suggested a num- ber of times, by which an electric arc was to be maintained in the cylinder of the engine, between two heavy platinum points, but this device, so far as can be found, simply figured in patent specifi- cations, and never came into actual use. The flame method is currently em- ployed in many good engines of the present day, and was put into its first practical shape more than fifty years ago, since which time it has undergone a variety of modifications. With the early non-compression engines, in which the pressure in the cylinder be- fore explosion of the charge was the same as, or even less than, the pressure of the atmosphere, flame ignition was a comparatively simple thing, and it was easy enough to transfer a flame from the outer air into the interior of the cyl- inder with little, if any, trouble from ex- tinction. In the early flame-ignition ex- periments the very simple expedient was adopted of providing a hole in the cylinder wall, which hole was uncovered by the piston after a portion of the stroke had been passed over, and the flame was sucked through it into the cylinder. The hole was either so small that no appreciable loss of pressure oc- curred upon explosion of the charge, or it was covered by a small valve which closed automatically as soon as the pressure in the cylinder rose. When the gases to which the flame was to be communicated, however, were under a pressure of some magnitude, as is the case in nearly all the gas engines of the present time, the difficulties of the igni- tion problem were at once increased. The method just referred to, and not in- aptly termed the ' ' touch-hole ' ' meth- od, obviously became inapplicable, and special valve devices had to be designed to meet the new conditions, a good ex- ample of one of them being that of the earlier Otto engine, as illustrated in the first paper of this series. Ignition of explosive gas and air mix- tures by contact with more or less highly heated metallic surfaces, or the hot-tube method, as it is now generally termed, was suggested independently by several investigators a number of years ago. The general scheme pro- 363 364 GASSIER' S MAGAZINE. posed was to ignite the gas and air charge by passing it through a metal tube heated to redness by a flame out- side of it, and this method is in success- ful use to-day in a large number of en- gines. Wrought iron is generally em- ployed for the tubes, though in a few engines platinum has been pressed into service, its higher cost being counter- balanced, in a measure, by its greater durability. A difficulty with the iron compressed air and gas charge to the tubes at the proper moment. The flame method and the hot-tube method just mentioned are the ones which seem to have secured the greater measure of popularity, being claimed, by their ad- vocates, to be more certain in action and cheaper and simpler in arrangement than the electric devices. The latter, however, are by no means allowed to rest under any such imputations of com- FIG. 98. -THB PACIFIC ENGINE MARINE TYPE. tubes is found in their rapid oxidation and furring, necessitating their more or less frequent renewal, but with their cheapness and the ease with which an old and worn-out one may be replaced by a new one, this objection is not so serious as might be supposed. In some engines the tubes are so screwed into the cylinders as to be constantly in com- munication with them, while in others valves are arranged which admit the parative inefficiency. A number of en- gine builders have devoted much en- ergy to their development, and as a re- sult this type of ignition device is now used with much satisfaction in some of the best engines on the market. A flexible electrode arrangement, which is employed in several of these devices, affording absolute certainty of contact in completing the electric battery cir- cuit, is one of the most important im- MODERN GAS AND OIL ENGINES. 365 provements that has been made in con- nection with them, and to it is mainly due their present satisfactory action. One of the forms of gas and oil en- gines, in which this arrangement is in FIG. 99. SECTION OF PACIFIC ENGINE. use, and which has attained much pop- ularity, especially for boat propulsion, is the Pacific engine, built both by the Union Gas Engine Company, of San Francisco, CaL, and the Globe Gas En- gine Company, of Philadelphia. One of the earlier designs of this engine, ar- ranged as a launch motor, with revers- ing gear and circulating pump for the cylinder water jackets, is shown in Fig. 98. In this A represents a relief valve, through which part of the compressed vapor may be allowed to escape to fa- cilitate starting up the engine. The throttle valve is marked B, while C and D are gas and air regulating cocks ; E is the reversing lever which, by being shifted from the upper to the lower po- sition, brings a back gear into operation and causes the propeller shaft to run in a reverse direction ; G is a clutch lever for stopping and starting the propeller shaft. The circulating pump H takes water through the bottom of the boat, and discharges it into the lower part of the water jacket around the cylinder, while the overflow pipe L from the upper part of the jacket is led out through the side of the boat above the water line. Water from the jacket may be drained off through the cock K. The coupling for connecting the engine with the pro- peller shaft is placed at the end of the secondary shaft /. The exhaust valve is marked J. The engine works ac- cording to the Otto cycle, and the charge, as previously intimated, is fired by an electric spark, I 7 and M being the wires from the battery, the former con- necting with an interrupting device, so that a spark is produced only at the be- ginning of every second down stroke of the piston. It will be understood that, like in the several other launch outfits, Vf- FIG. 100. THE VAPORIZER. described in some of the preceding pa- pers, the engine itself is never reversed, but runs continuously in one direction, and the direction of motion of the pro- peller shaft and the secondary engine 3 66 CASSIER'S MAGAZINE. FIG. IOI.-A DOUBLE-CYLINDER PACIFIC ENGINE. MODERN GAS AND OIL ENGINES. 367 shaft alone is changed, when desired, by the lever arrangement already men- tioned. The valve gearing of the engine, which is one of its special features, and entirely unlike that of any other engine in the market, is illustrated more clearly in the sectional view, Fig. 99. It will be noticed that on the crank shaft is a cam, /*, having two grooves which run parallel part of the way around, and then intersect each other. A segment- shaped finger, S, rests in one of these grooves, and as the engine shaft re- volves the finger is guided through the intersection from one groove to the other, and carries a swinging arm, T, under the exhaust valve stem once in and air mixture into the cylinder is, at such times, prevented simply by the fact that the exhaust passages are very large as compared with the gas and air inlet, and the exhaust valve, as stated, is held wide open, and there is thus less resistance to the flow of air through them than there is to the flow of gas and air mixture through its regular admis- sion port and valve. The latter will, therefore, not open, and, consequently, no working charge can enter the cylin- der until the governor catch on the ex- haust valve rod is released by a falling- ofT in the engine speed and the exhaust valve is allowed to close. The design of the engine has latterly been somewhat modified, but only in FIG. 102. VALVE GEAR OF THE UNION ENGINE. every two revolutions. The cam Q at those periods lifts the arm 7", and with it the exhaust valve rod, opening the valve and permitting the escape of the waste gases from the cylinder. The governor acts directly on the exhaust valve rod, holding it up, with the valve open, whenever the speed of the engine rises above the normal. The effect of this, to begin with, is that neither back pressure nor partial vacuum are created in the cylinder when running without working explosions, air from without being alternately drawn into the cylin- der and expelled from it through the exhaust pipe. Admission of fresh gas details which but slightly change its appearance, the manner of operation remaining exactly the same. A double- cylinder engine is built on essentially the same lines as the one just described, and is shown in Fig. 101. This illustra- tion also shows the improved form of vaporizer with which the engine is fitted when using gasoline, and which takes the place of the various forms of car- burettors employed in connection with most other engines. The vaporizer is shown attached to the lower right hand part of the engine, at the side of the base near the fly-wheel, a detail view being given in Fig. 100. It consists of 368 CASSIER'S MAGAZINE. either a glass or metal body E, glass being used in the one shown attached to the engine, and inside of this is a ball-shaped valve, N, seated on the end of a tube connected with the air inlet pipe G. Connection from the vapori- zer to the engine cylinders is made at M, A casing around the exhaust pipe of the engine affords an annular space through which the air is drawn on its way to the vaporizer inlet G, and is heated by contact with the hot exhaust pipe. As the air enters the vaporizer body, it lifts the ball valve A 7 ", and the latter strikes against the spindle O of the gasoline valve, raising it and per- flow of gasoline through the opening, C, if desired, when starting the engine. The gasoline and air inlet valves O and N, of course, open only during the suc- tion strokes of the pistons, remaining shut during the remainder of the work- ing cycles. In actual practice this vaporizer has been found to perform admirably, and some preliminary trials made even with ordinary oils have been found to give promising results. The vaporizer being directly attached to the engine, and not a separate addi- tion like the several currently used carburettors, makes the whole outfit comparatively simple and self-con- FIG. 103. VERTICAL SECTION THROUGH VALVE CHAMBERS OF UNION ENGINE. mitting a small quantity of gasoline to flow into the vaporizer through the cock Ay from a conveniently placed tank at a higher level. The gasoline so admitted is at once turned into vapor by the heated air and is drawn oft on its way to the engine through the connec- tion M. The low^er end of the valve N\s shown at H where a leather washer, I, is pro- vided on a collar, /, the latter prevent- ing the valve from lifting too high. The upper part X X of the vaporizer proper is arranged so that it may be revolved by loosening the screw D, enabling the attendant to observe the tained. The stationary Pacific engine is, in all essential details, the same as the marine type except that the reversing and clutch gears are omitted. Another engine, of the horizontal type, however, made by the same builders, and known as the Union en- gine, is shown in Fig. 104. Details of the valve gear and igniting device are shown in Figs. 102 and 103, the former representing an arrangement slightly different in appearance from that seen in the general view of the engine in Fig. 104, but exactly the same so far as the manner of operation is concerned. Motion from the crank shaft C of the MODERN GAS AND OIL ENGINES. 369 FIG. 104. THE UNION ENGINE. engine is reduced and transmitted to the cam shaft A through a series of in- tervening gear wheels not shown in the illustration, and the several cams on this shaft A operate on the cam rollers B and D, the former being on a rocker arm which works both the inlet and exhaust valves at the same time through a bell crank, E, while the latter is on another rocker arm controlling an elec- trode disc, F. The inlet- and exhaust valves are designated by the letters G and H, respectively, and it will be easily seen that when one of these valves is closed, the other is opened, and vice versa, a small rocking beam, y, being interposed for this purpose. Mounted on the engine crank shaft is also the governor with its restraining spring and weight, K, which latter, un- der the influence of excessive speed, moves outwards and, in the course of its revolution, depresses the catch lever L. The latter when so depressed hooks on to the upper end of the rocker arm B when the latter reaches its extreme right hand position, and keeps it there, with the inlet valve G closed and the exhaust valve H wide 4-23 open, until the speed becomes slower and the governor weight again moves inward and no longer presses down the lever L. As in the case of the Pacific engine, previously described, the exhaust valve, in virtue of this arrangement, is held open constantly while the idle strokes of the piston are being made, air being freely drawn into and expelled from the engine cylinder through the exhaust pipe during this period, so that there is no possibility of a partial vacuum being formed in the cylinder, or of back pressure being created. The current interrupter for the elec- tric igniting device is shown at M, and requires no special explanation as its manner of working is quite clear from the illustration. There is, it will be noticed, a flexible contact strip carried by a collar on the rod operating the bell crank E, and this strip, in moving back and forth with the rod in ques- tion, makes and breaks the electric contact at M at the proper periods which are determined both by the gov- ernor and by the nature of the reduc- 370 GASSIER' S MAGAZINE. ing gearing between the crank shaft C and the cam shaft A. A vertical section through the ex- haust and inlet valve chambers, show- ing also the nature of the igniting elec- trode arrangement which is somewhat different from that used in the Pacific engine, is given in Fig. 103. The rod R, in Fig. 102, connects by means of the pin P, with the electrode disc /% seen in both views, and gives it an oscillating motion which, of course, is imparted also to the electrode A" carried on the cylinders placed opposite one another in two pairs, and with a modified form of valve gear has been built and has given particularly good results in point of steadiness of speed. The igniting devices described form subjects of sev- eral patents. An English engine, which has achieved considerable prominence, is the Stockport engine, built by Messrs. J. E. H. Andrew & Co., Limited, of Stockport. In its early form it was of the double-end design that is to say, FIG. 105. THE STOCKPORT ENGINE, BUILT BY MESSRS. J. E. H. ANDREW & CO., LTD., STOCKPORT, ENG. end of the electrode disc spindle. This electrode A", as will be at once under- stood, is thus made to alternately strike and clear the flexible electrode S, which is connected with one of the battery wires, and when contact is thus made and broken at this point, contact also being made at the interrupter M', in Fig. 1 02, a spark is produced which fires the explosive charge in the inlet valve chamber and cylinder. A four- cylinder engine of this type, with the there were two horizontal cylinders placed opposite each other, one being the motor cylinder proper, and the other, the compressor cylinder, and the crank was placed midway between the two. A number of modifications have, however, of recent years, been insti- tuted in the design, so that, in one of its latest shapes, the engine is substan- tially like that shown in Fig. 105. In this, it> will be observed, there is no separate compressor cylinder, and the MODERN GAS AND OIL ENGINES. 37i FIG. I06. VERTICAL STOCKPORT ENGINE FOR HOISTING. -engine works according to the regular Otto cycle, with, normally, one explo- sion in every two revolutions. The valve gearing and governor are oper- ated from a secondary shaft running along the side of the cylinder, and driven from the main shaft through in- tervening bevel gears. Firing of the working charge is accomplished by a tube igniter, and the valves all are of the poppet type. On the larger en- gines the type oi governor shown in Fig. 105 is used, while the smaller sizes are provided with a vibrating governor shown on page 375, in which a weight, riding on a spring, is moved by a vi- brating lever. So long as the engine runs at a certain speed the weight keeps in position a small hit-and-miss lever, and gas enters the cylinder of the en- gine. With any variation of speed above the normal, however, the posi- 372 CASSIEX'S MAGAZINE. MODERN GAS AND OIL ENGINES. 373 tion of the weight changes, moving the valve operating lever out of gear and cutting off the gas supply. For elec- tric lighting and other work requiring very steady motion, a special governor is used for varying the explosive mix- ture, so that the speed may be con- trolled without missing explosions in the cylinder. Messrs. Andrew & Co., who, by the way, are, next to Messrs. Crossley Bros, of Manchester, England, proba- bly the oldest firm of gas engine build- ers, are the makers also of the Bisschop engine an engine which will probably appeal only to the smaller power its connections extending upward, and motion from the crosshead being im- parted to the crank by a vibrating lever arrangement. In order to prevent sticking of the piston in the cylinder owing to the rather high temperature which it attains, it is fitted quite loosely without rings, and the pressure from the gas explosions is so slight that the leakage past the piston is not serious. The flame ignition method is used to fire the charge, the flame being drawn into the cylinder through an opening in its walls on the already mentioned ' ' touch-hole ' ' principle. In the matter of size of engines it is EXHAUST FIG. IO8. SECTION OF END OF CYLINDER OF STOCKPORT ENGINE. FIG. 109. SIDE VIEW OF STOCKPORT ENGINE STARTING GEAR. users, being a surviving form of the early non-compression type of motor which has been almost completely driven out of the commercial gas en- gine field by the developments of recent years. In this engine the principal end aimed at is to get a small, workable engine with the least possible compli- cation, economy of gas being a second- ary consideration. Instead of having a water jacket, the cylinder has cast on it a number of radiating ribs, which carry away the heat of the explosions and keep the temperature of the cylin- der walls at a reasonable point. The cylinder is vertical, the piston rod and interesting to note that Messrs. An- drew & Co. are now building Stock- port engines indicating as high as 150 horse-power in a single cylinder. One of the largest gas-driven electric light installations in England, at Morecambe, was equipped with engines by them, the plant comprising three Stockport engines of sixteen horse-power each, a Dowson gas plant, and three dynamos of 300 lights each, besides a storage battery outfit. Messrs. Tangye, Lim- ited, of Birmingham, and Messrs. Cross- ley Bros., Limited, of Manchester, Eng- land, also have turned out noteworthy engines of large size, developing from 374 CASSIER'S MAGAZINE. MODERN GAS eighty-five to 100 actual horse-power. One of the Tangye engines, rated at 115 indicated horse-power, furnishes power for fine weaving machinery in a Belfast mill, and is stated to give emi- nent satisfaction, both in point of econ- FIG. III. VIBRATING STOCKPORT GOVERNOR. omy and steady running. The Cross- ley-Otto engine is, in the main, similar to the Otto engine made in the United States, and already described in the first paper of this series, so that it is not necessary to enter into its details here. In nearly all the larger sizes of gas engines some form of starting device is now used which dispenses with the ne- cessity of turning the fly wheels by hand a proceeding which is not only diffi- cult, but, in some cases, would be quite impossible. Of these starting gears that used by Messrs. An- drew & Co. on their engines is shown in Figs. 108 and 109, the former representing a side view, and the latter a sectional view of the end of the cylinder. At A is a Bunsen burner for heating the ignition tube B. At C is the ex- haust valve, and above it a gas admission valve E. Above, and at the outer end of the ignition tube B, is an air outlet valve, with handle D. At F is a timing valve for fixing the period at which the gaseous mixture shall be admitted to the ignition tube. When it is desired to start the engine, 375 the gas admission valve E over the exhaust valve C is opened. Gas com- mences to flow into the cylinder, which then contains only air at atmospheric pressure. This air is allowed to escape in quantity equal to that of the gas ad- mitted by the valve at the end of and above the horizontal part of the igni- tion tube B. As soon as sufficient gas has in this way flown into the cylinder to produce an explosive mixture where it enters into the ignition tube, ignition takes place and the engine starts. The valve E and the air outlet valve are then closed, and the gas main, which had been previously closed, is opened and gas allowed to flow into the gas bag. Messrs. Tangye' s self-starter consists mainly of an air pump worked by hand, by means of which the space be- hind the piston may be filled with gas and air under a slight pressure. Some of this mixture enters the ignition tube and is fired, giving the initial impulse, after which the engine continues run- ning in the regular way. Messrs. Robey & Co., of Lincoln, England, to whose engines reference was made in the July number of this magazine, use on their large engines what is known as the Clerk-Lanchester starter, illustra- ted in Fig. 112. It consists of a cham- FIG. 112. THE CLERK-LANCHESTER STARTING GEAR. ber A, outside and separate from the engine, and of a capacity rather greater than that of the cylinder, with which it is connected by a pipe E, and check valve W. The crank being. set 376 MAGAZINE. at about fifteen degrees, gas is turned on by a tap X, from the gas main G, and it flows into the chamber by the pipe J, mingling with the air therein and forming an explosive mixture. At the same time gas flows into the cylin- der by the pipe shown. When the and this forces the gas in E into the cylinder under a pressure of about fifty pounds per square inch, and forms there a compressed mixture which, on ignition, gives an average pressure in the cylinder of about eighty-five pounds per square inch, and starts the FIG. 113. OIL ENGINE BUILT BY MESSRS. J. M. GROB & CO., LEIPSIC-EUTRITZSCH, GERMANY. mixture is so far formed as to be in- flammable, it lights at the jet Y, and a little later becomes of sufficient ex- plosive strength. The tap X is then closed, and the ejecting pressure ceas- ing, the flame at Y shoots back, ignites the t gaseous mixture in the chamber, engine and its load. In the line ol petroleum motors Germany would ap- pear to have kept well abreast of other countries, and a number of Ger- man makers have established agencies outside of their own domain, notably in England, for the sale and general MODERN GAS AND OIL ENGINES. 377 advertisement of their product, com- peting, thus, directly with a host of other engines in their own territory. Among these is the firm of J. M. Grob & Co., of Leipsic-Eutritzsch, who are building an engine which in Germany, at least, seems to be well known, and to have found considerable favor for all kinds of work marine, stationary and portable. It appears, in fact, to be a modification of the Capitaine engine, already described in one of the earlier papers of this series. Though on the market for only about two years and a half, something like 1400 of these engines are said to be now in use. The sectional view clearly explains the working mechanism. The engine belongs to that class of petroleum motors in which the oil is vaporized in a heat- atomizer valves closing automatically, and explosion of the charge at the be- ginning of the second down-stroke of the cycle is produced by some of the mixture having been forced into hot vaporizer, which serves the purpose of an ignition tube. The working stroke having been performed, exhaust during the second up-stroke of the piston takes place through the valve E, which is worked by a long shaft receiving motion from the crank shaft of the engine through intervening gear wheels. The valve rod is not con- nected to the exhaust valve, but simply strikes against the valve spindle and pushes it upward, the seating of the valve being effected by a spring. The valve is opened only once in every two rev- olutions of the main shaft. Heating of the vaporizing FIG. 114. VERTICAL SECTION OF THE GROB ENGINE. ed chamber before being drawn into the working cylinder, the vaporizing cham- ber being marked V in the illustration. Working, as the engine does, on the Otto cycle, it draws in air on its first down-stroke through the valve A, and petroleum through the atomizer S, the petroleum spray being vaporized in V before it mixes with the fresh air and enters the working cylinder. The vapor and air mixture is compressed on the next up-stroke of the piston, the air and chamber is effected by the lamp L, and cooling water for the cylinder jackets enters, and escapes through the connec- tions WW. The oil pump P, which supplies oil to the vaporizing chamber, is controlled by the governor in such a way that the amount is varied in accordance, with the demand for power. The oil used is of the ordin- ary kind burned in lamps for illuminat- ing purposes. ( To be continued.} RECENT IMPROVEMENTS IN WATER VALVES. By John Richards, Mem. Am. Soc. M. E. THE drawings from Fig. i to 5 show some water valves invented by Mr. C. I. Hall, of San Fran- cisco, Cal. , and employed by the Cahill & Hall Elevator Company, to hoisting or elevator machinery, in their practice. These valves were aptly described by the inventor in one of his first specifi- cations as permitting the water to flow only in the direction intended, which is the leading characteristic of all the designs. The company are makers of ' ' hydro- steam ' ' elevators, in which the im- pelling force is steam pressing upon the water, which actuates the hydraulic pistons, the water by reason of its in- elasticity performing the required func- tion of positive movement and " abut- ment," the same as in the case of com- mon hydraulic elevators. The direct steam pressure dispenses with pumps, accumulators and so on, such as are 378 employed when the price of water does not admit of its use from the public service. The water employed in the hydro- steam system, while inelastic in itself, does not produce regular or safe move- ment when controlled by common stop' valves, for the following reason : Sup- pose, for example, a load is being raised, and the cage is stopped on the way to receive an additional load, as in the case of passengers getting on at: the different floors of a building. When the cage is stopped there is an equi- librium between the load and the steam pressure acting on the water, but when the valves are opened to go on, or to go down, the static pressure will be in- sufficient to sustain the new load, and the cage will suddenly drop until the steam rushes in to check the back-flow of the water and balance this added load. For this reason common stop valves cannot be employed. In the case of removing a part of the load during a trip of the cage the same difficulty occurs. The pressure at the time of stopping the cage remains in the steam receiver, and when valves are opened this force is too great for the reduced load, and the cage is sud- denly shot upward until the forces are balanced. The present valves are em- MODERN GAS AND OIL ENGINES By Albert Spies, Mem. Am. Soc. M E. Bighth connection with the different ig- nition methods referred to in the preceding paper, it may not be amiss to mention that the case of in engines using either flame or tube igniters the consumption f of gas by the igniting or heat- ing burners is an item not al- ways duly taken into account, and may assume appreciable propor- tions. Where gasoline or some other oil is used in such engines instead of gas, and where the latter is not to be had, the gas flame must, of course, except in a few engines of special design, be sup- planted by an oil torch, and the same additional fuel consumption, above that taking place in the cylinder of the en- gine itself, is there encountered, the torch, moreover, being a rather unde- sirable annex to the whole outfit. These circumstances have, in a great measure, helped to stimulate the im- proving of electric igniting devices, and several of them are now affording very satisfactory accounts of themselves. This much may already have been gathered from what has gone before. With the electric igniter there is, of course, to be considered the expense of the battery which furnishes the electric current, but this has been claimed, and with good reason, to be a very small proportion of the whole operating ex- pense, a much smaller one, in fact, than that represented by the gas or oil cost in a flame or tube igniter. It would seem to be a pretty fair con- clusion, under the circumstances, that electric igniters are destined to a yet wider application and a growing share of favor. Not less important than the methods of igniting are those of governing, and considerable ingenuity has been ex- pended for years past in developing various contrivances designed to satis- factorily solve the gas engine governor gear problem. At first thought, some sort of throttling gear by which the gas or oil vapor supply to the cylinder is gradually reduced as the speed increases, and vice versa, is apt to suggest itself as a desirable one, and, as a matter of fact, many gears of this kind have been made and are used, both Lenoir and Hugon having followed this method of governing in their early engines. Its wastefulness, however, becomes apparent on even slight consideration, so that one may well wonder that at this late day the throttling governor is still countenanced in gas engine practice. It is obvious that if, with such a gov- ernor, the volume of gas or oil vapor admitted to an engine cylinder is dimin- ished, the volume of air admitted is cor- respondingly increased, and it is well known, too, that the limits of variation permissible in explosive mixtures of gas and air are comparatively narrow, so that if, in a total volume of mixture, the volume of gas either exceeds or falls short of a certain, elastic proportion, no explosion can be produced. While, therefore, a gas throttling governor may either increase or diminish the force of the explosions in the engine 437 438 GASSIER J S MAGAZINE. cylinder by varying the strength of the gas and air mixture between these lim- its, yet if one of the limits be passed, and the gas volume, for instance, be too greatly diminished, ignition of the mixture will be missed and whatever to increase, gas being simply pumped through the cylinder and wasted until its proportion is again increased, by the subsequent opening of the gas valve to that point where the mixture once more becomes explosive. FIG. 115. THE PITTSBURGH ENGINE, BUILT BY THE FURL GAS AND MFG. CO., PITTSBURGH, PA. gas has been taken into the cylinder will then be discharged into the exhaust pipe unburnt and without having given up any of its energy. Under these cir- cumstances the engine will work ex- actly as though no gas whatever had been admitted, and the speed will cease No better evidence is needed of the fact that the wastefulness of the throt- tling governor method has met with a fair share of recognition, than the ex- tended application which for years has been given to what have been termed ' ' hit - and - miss ' ' governors. With MODERN GAS AND OIL ENGINES. 439 these the strength of the explosive gas and air mixture is never changed, but the number of explosions in the engine cylinder in a given time is varied to suit the prevailing requirements, being in- creased when the speed falls below, and decreased when it rises above a certain normal / or putting it in a slightly dif- ferent way, when the speed falls off, the governing device hits the stem of the gas supply valve, causing the latter to open and admit gas into the cylinder, while when the speed becomes too high, the governor by changing its position, misses the gas valve stem, the valve consequently remains closed and no working charge reaches the cylinder. One objection to this method of gov- erning always has been that it gives the engine a jerky, unsteady motion which is fatal to success in electric light work, and in order to overcome this, some engine builders now provide the gov- ernor cam which strikes against the gas valve spindle with several steps, so that instead of being either full on or full off, the gas valve may be opened through intermediate degrees. The strength of the explosive mixture -may thus be varied to some extent, but whenever the lower limit of gas percentage necessary to constitute an explosive charge is reached, the gas valve is closed entirely, and the engine then runs without ex- plosions until the speed again drops. The stepped-cam governor, in fact, combines a throttling with a cut-oft action. The ideal method of governing, how- ever, would seem to be one akin to that followed in modern, high-class steam engine practice, one by which the strength of the working charge would be kept always the same and only the quan- tity for each working stroke would be varied. In all processes of combustion there is a certain percentage of oxygen, which, by combining with a certain per- centage of combustible, produces a maximum effect, and any variation from these relative proportions will represent a loss of efficiency. This is fully as true of the combustion of gas in a gas engine cylinder as of the combustion of any other kind of fuel in any other place, and the economic bearing of maintain- ing a constant and certain strength of explosive mixture in gas engine work will, therefore, be at once recognized. An engine in which advantage has been taken of this circumstance is that recently put on the market by the Fuel Gas and Manufacturing Company, of Pittsburgh, Pa. , and known as the Pitts- burgh engine. In external appearance it strikes one much as one of the well- known Westinghouse steam engines. As in these, a crank case encloses the bearings and lower end of the cylinders. This case is filled almost up to the shaft with a mixture of oil and water, into which the crank shaft and connecting rods splash at every revolu- tion, so as to completely deluge the bearings, piston and interior of the cyl- inders, thereby not only affording copi- ous self-lubrication, but also cooling the piston. Oil for the crank case is intro- duced through the main bearings, which are supplied from the only two oil cups on the entire engine. A simple pipe connection with a city main supplies the necessary water. Another pipe, serv- ing to carry off the overflow, is made, by means of a funnel head, to indicate the level of the lubricants in the crank chamber. All the Pittsburgh gas engines are built with two cylinders on a single shaft, and, as usual, abnormal heating is obviated by the employment of water jackets. Each revolution made by the engine operates valves admitting the gaseous fuel alternately to the one or the other cylinder. As the period of admission is controlled by a positive action, the crank shaft receives an im- pulse once each revolution, no matter what the load, but the energy of that impulse is predetermined by an inde- pendent piston valve. In order that the maximum amount of energy may be developed by the explosion of the gaseous fuel, there is, as already ex- plained previously, but one value that the relative amounts of gas and air can bear to each other, and the company design their measuring piston valve so that, it is claimed, it always admits gas and air in their correct proportions for 440 CASSIER'S MAGAZINE. FIG. Il6. TWENTY-FIVE HORSE-POWER UNION MARINE ENGINE. MODERN GAS AND OIL ENGINES. 441 FIG. Iiy. THE CHARTER ENGINE, BUILT BY THE CHARTER GAS ENGINE CO., STERLING, ILL. producing the desired maximum result, but at the same time varies the total amount of mixture directly as the work of the individual piston stroke. The governor is mounted upon the shaft, between the cranks, and, by direct connection between the eccentric rod and valve stem, insures an accurate and positive travel to the measuring slide valve. The igniter employed is of the electric spark type. Unfortu- nately, more complete particulars of this engine are not available at the present time. In connection with the Union engine, described in the preceding paper, and built, as there stated, by both the Union and the Globe Gas Engine Company, of San Francisco and Philadelphia, respec- tively, the illustration on the opposite page will prove interesting, represent- ing, as it does, the latest type of double cylinder, marine engine of Union make, rated at twenty-five horse-power. This engine, according to advices received within the past few weeks from the builders, was completed only a short time ago, and is now in a schooner in San Francisco Bay giving highly satis- factory results. It is the first one ot the kind that they have built, and is probably the largest marine oil engine now in use, except a four-cylinder engine of forty-five horse-power of somewhat different form which was turned out by the same builders a number of years ago. The main features of the engine are essentially the same as those of the horizontal Union stationary engine, shown in the September number ; the valves and igniting devices are similarly operated, and the same form of vapor- izer as that then illustrated is used. The propeller reversing gear shown tends to give the impression that there is considerable complication about the engine, but this will disappear upon closer study of the details. A muffler 442 GASSIER' S MAGAZINE. around the exhaust pipe is used to deaden the noise of the exhaust. The schooner in which the engine is placed is S9/^ feet long with 14 feet beam, and carries freight between San Francisco and Bodega Bay. On her trial trip over the Government course in San Francisco Bay she developed a speed of over 8 miles an hour. This was re- garded as a very good showing, as the engine was new and stiff, and the boat was not built for speed. The owners FIG. 1 18. DETAILS OF THE CHARTER KNGINE. of the vessel also have a 10 horse- power engine in one of their other boats. As the last of the series of illustra- tions are presented those of the Charter gas and gasoline engine, which is made by the Charter Gas Engine Com- pany of Sterling, 111., and which in some respects is similar to the Caldwell- Charter engine described in one of the earlier papers. When using gasoline no carbu retting device is used between the oil tank and the cylinder, but the oil is delivered directly into the suction pipe by a pump controlled by the governor, a few drops only being admitted at a time. There are three cut-offs between the tank and engine cylinder, viz., a cock at the tank, a throttle valve to regulate the amount of gasoline de- livered, and the plunger of the pump just mentioned. The engine works ac- cording to the Otto cycle, the exhaust valve being pushed open at every other revolution by a rod worked through re- ducing gearing from the crank shaft. The arrangement of the gasoline pump and the manner in which it is controlled by the governor will be easily under- stood both from the general view of the engine and from the details shown in Fig. 1 1 8, the latter representing an elevation and a plan of the governor and its connections. The governor, it will be observed, is mounted on a sleeve on the main shaft, and when the gov- ernor balls, under the influence of un- duly high speed, move outward, the sleeve is carried along the shaft and moves with it a cam roller, which is mounted loosely on the upper end ot the rocker arm A. When so displaced, this cam roller is missed by the cam on the larger of the two gear wheels shown, and the rocker arm, which is connected with the injector rod operating the gas- oline pump, remains undisturbed, and no gasoline is permitted to enter the suction pipe leading to the cylinder. When, on the other hand, the governor balls are in the position shown in the engraving, the cam on the larger gear wheel will, in the course of its revolu- tion, come in contact with the cam roller on the arm A, force it over to the right, and cause a stroke to be made by the gasoline pump through the intervention of the injector rod. The displacement of the pump plunger then admits the proper gasoline supply to the suction pipe, and the entering air carries the oil along into the cylin- der in which the mixture, after com- pression, is fired by a tube igniter. For engines above six horse-power a slightly different form of governor connection is employed, the working principle, how- ever, being the same. The engine is turned out in sizes of from one and AN EVAPORATIVE SURFACE CONDENSER. 443 one-quarter to thirty-five actual horse- power. Before finally leaving the subject, the writer would attempt to forestall criti- cism on the score of incompleteness of the series of articles presented by stat- ing that no attempt could be well made to embrace in them all the engines of the class considered which are now in use and built in different countries. It was deemed advisable, in fact, at the outset to try to present only engines of English and American make, and such foreign designs as were represented in English and American markets, and even this undertaking was found beset with many difficulties. Aside from the fact that the addresses of some makers of engines could not be ascertained, there were a number of builders who simply ignored requests for information, and others again who flatly declined to furnish particulars of any kind. That the list of engines considered in these articles is by no means comprehensive is, therefore, natural. AN EVAPORATIVE SURFACE CONDENSER/ By James H. Fitts. THE condenser herein described was built at the Virginia Agri- cultural and Mechanical College, at Blacksburgh, Va., after some obser- vations were made on the rate of evaporation of water at different tem- peratures, and with a current of air passed over its surface. Its perform- ance has been successful to such a degree that this paper is presented, in the belief that it will be of general interest to the profession, and that it gives a practical solution of the question of condensation of vapor with a small water supply. The condenser consists of two rec- tangular end chambers connected by a series of horizontal rows of tubes, each row of tubes being immersed in a pan of water. Through the spaces between the surface of the water in each pan and the bottom of the pan above, air is drawn by means of an exhaust fan. At the top of one of the end chambers is an inlet for steam, and a horizontal diaphragm about midway causes the steam to traverse the upper half of the tubes and back through the lower. An outlet at the bottom leads to the air pump. * From a paper presented at the International Engineering Congress at Chicago. The condenser, exclusive of connec- tion to the exhaust fan, occupies a floor space of 5' 4^" x i' 9^", and is 4' iy 2 " high. There are twenty-seven rows of tubes, eight in some, and seven in others ; 210 tubes in all. The tubes are of brass, No. 20 B. W. G., ^" external diameter and 4' 9%" in length. The cooling surface (internal) is 176.5 square feet. There are twenty-seven cooling pans, each 4' 9^"xi' 9^", and 17-16" deep. The pans have galvanized iron bottoms, which slide into horizontal grooves %" wide and %" deep, planed into the tube sheets. Wooden strips are fitted into the grooves below the bottoms. The tube sheets form the ends, and angle irons i^"x^"x;Hj" bolted to the galvanized bottoms, the joints packed with wooden strips, form the sides. The total evaporating sur- face is 234.8 square feet. Water is fed to every third pan through small brass cocks, and tjjf" overflow pipes feed the rest. A wood casing connects one side with a 30" Buffalo Forge Co.'s disk wheel, which is belted to a 3" x 4" vertical engine. The action of this condenser is clear. The passage of air over the water sur- faces removes the vapor as it rises, and 444 CASSIER'S MAGAZINE. thus hastens evaporation. The heat necessary to produce evaporation is obtained from the steam in the tubes, causing the steam to condense. It was designed for the college shop engine, to condense 800 pounds steam per hour, and give a vacuum of twenty-two inches, but it was found practically impossible to get the long exhaust pipe air-tight, on account of its numerous connections. Direct connection was therefore made with the boiler. A number of runs of several hours' dura- tion have been made with a boiler press- ure of sixty to seventy pounds. The cooling water was run into a barrel placed overhead and drawn from the barrel. The water of condensation was weighed. The following gives average results : Boiler pressure, pounds per square inch per gauge, 65 ; temperatures in Fahrenheit degrees steam, 311 ; cool- water (initial), 60 ; water in pans above diaphragm, 140 ; water in pans below diaphragm, 115 ; hot well, 149; air, 70; dew point, 62 ; working strokes of air pump, 90 ; revolutions of exhaust fan per minute, 740 ; velocity of air in feet per minute, 2300 ; quantity of air moved in cubic feet per minute, 6500 ; horse-power expanded in driving fan, YZ ; barometer in inches, 28 ; cooling water used per hour in pounds, 1350 ; steam condensed per hour in pounds, 900 ; vacuum in inches of mercury, i6}4 ; vacuum reduced to barometer at thirty, 18^. The overflow pipes for regulating the supply of water were found to be too small, so that at times some pans would be too full, causing waste of water over the edges, and at others the tubes would be uncovered, with reduction in effi- ciency. This loss of cooling water will account for the amount being so much in excess of the water of condensation. The amount of steam condensed, it there had been no waste of water, would have been about thirty pounds less than that shown. Accurate analysis of the transfer of heat could not be made on account of this waste. An approximate analysis, however, shows that the cooling water required is practically equal in amount to the steam used by the engine, and since consumption of steam is reduced by the application of a condenser, its use will actually reduce the total quan- tity of water required. The condenser is still in a crude form, and there are many improvements to be made in it. Enough has been done, however, to demonstrate that it is ap- plicable in any situation, that it is not expensive to construct, is perfectly accessible for cleaning, requires small power to operate, and will give a vacuum of from twenty to twenty-two inches. The floor space required is moderate. GAS AND OIL ENGINES. A T no time in the history of gas and oil engines has the interest in their application to every-day work been so strongly marked as at present. To- gether with electric motors, these engines have done much to displace small, and in many cases even large, steam engines, and power users have commenced to realize that for economical, reliable and con- venient driving, engines of that class are entitled to very careful considera- tion. This is shown by every new con- tribution to the literature of the subject, and engineers' discussions of it at meet- ings of technical societies. Among the latest, and perhaps most interesting, of these discussions is one which was held a short time ago before the American Society of Mechanical Engineers on the occasion of a "Gas and Oil Engine Evening," and to the facts presented at that time, and repro- duced here, in part, it was thought well worth adding a number of illustrations of some of the most recent applications of the engines considered. These are all suggestive in their way and tell their own stories at a glance, more directly and more convincingly per- haps than pages of texts. The subject was introduced by Mr. S. A. Reeve who, among other things, said : ' ' The status of the gas engine depends entirely upon the surrounding condi- tions. A plant exists merely because the sun shines, and the seed has been planted. Unless the surrounding con- ditions are favourable, the plant cannot exist, and the amount of its growth, and the character of its growth, depend 5-2 entirely on the surrounding conditions. The gas engine follows this general law, in that its status to day is what it has been forced to be, and what it has been allowed to be by general commercial and engineering conditions of the world. Practically all other power that is in use is steam power. I do not lose sight of the tremendous amount of water power that is in use. But water power is restricted to certain localities, and the gas engine is not. It comes into com- petition only with those forms of power which are applicable to almost any locality or set of conditions, and, aside from gas power, steam power is almost the only other occupant of that class of prime movers. " The factory and the steam engine grew up together, and the idea that we carried in our m inds of a commercial man- ufacturing plant, driven by any power, was a set of tools, driven by a central motor through the medium of a line of shafting and a number of belts. That scheme of industrial works grew in size and importance until it had reached tremendous proportions, and in certain lines of industry it still survives, and will continue to survive in the future in still larger sizes, and on a still more important scale. But for the vast ma- jority of industries, these species of manufacturing which involve a varied number of processes and departments, and involve the production of a com- paratively complex commodity, such, for instance, as the building of steam- ships or railway cars, or the complicated machines involving woodwork and iron- work and steel-forging work, and all that sort of thing, the modern factory is a collection of factories. ' ' The various factories may be merely departments, merely different rooms in one building or on one floor. But, at any rate, the factory now consists of a large number of departments, and those 48 r 482 CASSIER'S MAGAZINE. GAS AND OIL ENGINES. 483 departments are quite distinct. They often run entirely independently, have separate foremen or superintendents, run different hours, and have different classes of labour. In some, labour is a small item, and power is larger. In others, power is a small item, and labour is the principal feature. All these various conditions make it almost im- possible for such an establishment to be driven by one central prime mover. "In the first place, distance of trans- mission comes in and consequent losses. In the second place come in varying conditions. Every engineer knows that no piece of apparatus can work well under varying conditions. We have, therefore, seen grow up the modern industrial works in which power has to be transmitted quite a distance, and subdivided among a large number of different sorts of tools. This was first attempted by shafting and belting, or by rope drives. But it is evident that the losses by transmission are very great. Consequently we have seen other schemes tried. First came the subdivision of the steam engine itself into a large number of units, and we have only to look about us in large factories to see steam-driven plants where the power is furnished from the central boiler plant to anywh ere from ten or a dozen to 70 different engines scattered all over the works, sometimes 20 or more in one room. Sometimes the losses in steam transmission are, under average conditions, less than for shafting and belting. Of course, no cast-iron rule can be given for all con- ditions. But the subdivided steam plant has come in to stay. Of later years, superseding the subdivided steam plant, comes in, first, compressed air, and then electrical transmission and sub- division of power. ' ' I have given the resume of the changes of the power question to show that the problem of the present is eco- nomical transmission of power, not economical development of power. Of course, economical development at the original point of production is of great importance, but it is vastly more im- portant to transmit it economically, be- cause the losses in transmission can easily exceed the largest losses possible in production. ' ' Those of you who have spent any time on the problem of the subdivision of power or its transmission, have seen that none of the systems heretofore pro- vided satisfy the question. They all involve tremendous losses in transmis- sion. They all involve heavy first cost, heavy expenditure for generating plant, transmission plant and redeveloping plant at the other end. For instance, in electrical transmission, if your total works need a thousand horse-power, be- sides your thousand horse - power of boilers, you must follow with a thousand horse-power steam engine, a thousand horse-power generator, your mains for carrying the electric power, and then, on top of that, a thousand horse-power of motors. That is, of course, losing sight of all small factors and percent- ages of loss. The present status of gas power, and also of its immediate prom- ise for the future depends upon this statement of the problem in this part that gas powers offers the ideal solution for the subdivision and transmission of power, the mechanical difficulties being, for the time, lost sight of. " In other words, let us suppose that a large industrial plant requiring, say, 1000 horse -power, subdivided into, say, 50 different units which are utilized at various points, at different buildings, on different floors, at different speeds, for different hours during the day, under different conditions of varying and steady load suppose that in such a plant as that, we install a 1000 horse- power gas generator or its equivalent, and then lead from it, or from the holder to a large number of gas engines, large central gas mains it is evident that the first cost is away below that of any system, with the possible exception of the subdivided steam plant, where our boiler plant corresponds to our generat- ing plant, our steam mains to our gas pipes, and our steam engines to our gas engines. "But there is one big advantage which a gas plant has over a steam sub- divided plant, in point of operation, 4 8 4 GASSIER 'S MAGAZINE. A 40 H. P. TANGYES GAS ENGINE AND GAS PRODUCER PLANT. BUILT BY MESSRS. TANGYES, LTD., BIRMINGHAM, ENGLAND. and that is, that in the steam subdivided plant, no matter how large a proportion of the load be off, the central generating plant must be run, and the fixed charges of running cannot be altered. Steam must be kept up, the boilers must be kept hot, the stack, if there be one, must be kept hot, and the labour must be there to take care of the whole mat- ter. I have myself tested one factory in which, for a large proportion of each day, the efficiency for the transmission of the power between the boiler plant and the work was 5 per cent., simply because they had to keep the whole plant going in order to move one small department. "With the gas plant that entirely disappears Your gas generator works for a certain number of hours a day, on whatever load or capacity is best suited to produce maximum economy, and as we all know, there is only one point in capacity in which any apparatus can work at minimum economy. Dur- ing those certain number of hours a day the generator makes gas and stores it in the holder. The gas generating plant is entirely unconscious of the consumption of power, provided it be large enough to fulfill all demands. The consumers of power, the foremen ot different departments, are as unconsci ous as is the generating plant of the consumption of power. They simply know that all they have to do is to turn on their gas and start their engine. They may run 24 hours in a day, while the gas generator runs eight, provided the total maximum production of the gas generator is large enough to cover the whole output of power. ' ' Comparison between such a gas plant and any plant relying upon trans- mission and subdivision of power by compressed air or by electricity, or by any scheme wherein the power is first developed by the steam engine, and then converted into another form, and then converted back again, is really hardly possible from the economical standpoint. The operation of any such GAS AND OIL ENGINES. 485 gas plant would be incomparably more economical than that of the compressed air or the electrical or the hydraulic system of transmission of power. I have entirely left out of the question the mechanical side of it, which I purposely wished to do. But for the merely com- mercial side there is an absolutely un- limited field for the development of power and its transmission and subdivi- sion in industrial works by means of the gas generator and the gas engine. "In nearly all large textile mills in New England, and in a great many other forms of industry, steam is used as much, and sometimes more, for heat- ing purposes, and boiling and dyeing than it is for power. In fact, the big promoter of steam power in New Eng- land, where it has proved an indispens- able auxiliary of water power, is the fact that the steam had to be had any- how. That is true also of compressed- air plants. There are a great many factories where compressed air is in- dispensable for blowing, furnishing draft, cleaning, and innumerable pur- poses to which it can be applied, and in a great many plants compressed air is used to transmit and subdivide power where no other system would be toler- ated, simply because the compressed air has to be there anyway, and, this be- ing so, they might a great deal better use the compressed air for power. " The same thing applies to electric- ity. Those factories relying on the electric current entirely for light may often bring the power question into secondary importance compared with light. If they have got to have their central engines and generators and mains for the productions and distribu- tion of light, and if they need light more than power, then, of course, the electrical transmission of power is the thing, without regard to the general arguments against it. But this same factor of the correlation of the system of transmission of power, and the sys- tem of transmission of other forms of energy needed in the works, applies also to gas. In fact, the gas producer has reached its present state of perfec- tion largely because of the fact that gas is the most economical form of fuel for a large number of industrial purposes metallurgical, for glass works, and for many kinds of cooking and heating and baking, where exact control of tem- A DOUBLE-CYLINDER OTTO ENGINE. BUILT BY MESSRS. CROSSLEY BROS., MANCHESTER, ENGLAND. 486 CASSIER'S MAGAZINE. GAS AND OIL ENGINES. 487 perature has to be had. In all those plants the power may again become secondary to other purposes in the factory, and in those plants where generators have already been installed for the purpose of supplying fuel gas, the gas engine follows as a natural sequence. 1 ' The reply to this side of the dis- cussion is that the mechanical difficul- ties have not yet been overcome ; that the gas engine, after having had spent upon it the best energy in the line of mechanical engineering which the world has been able to produce for some thirty years, is still more crude in a great many mechanical features than was the steam engine of a century ago. It is still very heavy. In nearly all of the devices only one impulse is received by the fly wheel for every two revolu- tions, so that the fly wheels are heavy. The regulation, as a rule, is accom- plished by simply dropping out a certain proportion of the impulses, instead of varying their strength, and the neces- sity for the ignition of the charge in a minute fraction of a second has led, until very recently, to extreme uncer- tainty in the matter of ignition and also in the question of perfection of com- bustion. The last is not so marked a feature, because, even with poor com- bustion, the gas engine is an exceeding- ly economical prime mover, but the mechanical difficulties still stand in the way of the accession of the gas engine to the proper field in which it belongs ; that is, the universal factor for the pro- duction and transmission and subdivi- sion of power in industrial works. ' ' At the risk of being considered rather superficial in skimming over this subject, I will take one step into the future and say that while gas engines have hitherto been almost entirely run with illuminating gas, yet already con- siderable has been done in the way of supplying gas engines with producer gas from special producers built for that purpose. There has also come upon the field I will just mention it the in- candescent gas burner that is, it has just begun to attract wide attention as being an established fact. These two coupled together first, that the gas engine can be run much more economi- cally upon producer gas, not illuminat- ing gas, than it can upon illuminating gas, and, second, that there is a means attained of producing illumination by a non -luminous gas, lead us to the sur- mise that the near future will see the distribution of energy all energy which is derived from coal in the form of a non -luminous, cheaply produced fuel gas, that this gas will be relied on entirely for power, for lighting, where gas lighting at all is permissible ; and where it is not, where the electric light is needed, that electric light will be pro- duced through the medium of gas en- gines, and that this same gas will be used for all sorts of fuel and heating purposes domestic heating and cook- ing and industrial heating of all sorts. ' ' I have tried to make as brief a statement as I could of the gas-engine problem as it appears to me to-day, not on the basis of the condition of the gas engine itself, but as a statement of its possibilities, the demands which are going to be made upon it in the near future, and what the near future may bring forth in the way of a powerful auxiliary to aid in the adoption of the gas engine as the universal prime mover." Prof. Wm. S. Aldrich said : " Some of the chief difficulties to the extended introduction of the gas engine have been gradually removed by the improve- ments in methods and apparatus for the manufacture of producer gas on a small, yet economical, scale. In this, as in other branches of engineering, the law of supply and demand operates to mut- ual advantage, and isolated gas-engine plants are rapidly coming to the front. On the other hand, for the distribution of power from a central plant to greater or less distances, gas offers peculiar ad- vantages. There are practically no losses in distributing the gas in pipe lines, except leakages, which can affect the economy of the distribution. Losses of pressure and temperature changes do not in the least affect the economy ol the gas engine at the end of the line. Therefore, the distribution of power by 488 CASSIER'S MAGAZINE. A GASOLINE TRACTION ENGINE. BUILT BY THE VAN DUZEN GAS AND GASOLINE ENGINE CO., CINCINNATI, OHIO, U. S. A. gas, and its utilization by gas engines, scattered over a widely extended area, may come to be a rival of some of the other methods. And the facility of storage and use of gas for heating are additional advantages. " It seemed doubtful for a long time whether gas engines could be made and economically managed in large units ; but their present use up to 3Oo-horse power and the contemplated manufact- ure of gas engines of 500 horse-power and upwards, leave no room for serious doubting. But it is open to discussion whether there is the same inherent gain in economy in the use of large gas en- gines as in the case of steam engines. Of course, on the general principles of power production, large units are more economical per horse-power than small units. Nevertheless, there is scarcely an argument advanced for the use of large steam engines that can be simi- larly advanced in the case of gas en- gines. "In the matter of arrangement of gas-engine cylinders, there is undoubted preference manifested for the vertical type, and in pairs, with cranks at 180 degrees apart. Four-cylinder or qua- druplex gas engines are being seriously considered, to gain an additional ad- vantage along the same lines as the two-cylinder, or duplex type, namely, a greater number of explosions per revolution, and, consequently, an in- creased opportunity to control the sup- ply and explosions according to the load. ' ' As rotating or rotary gas engines have been suggested, it may be well to note some of the advantages arising from using the explosions of the gas in much the same manner as the Pelton wheel utilizes the steadily applied im- pact of the water. The losses due to connecting rod mechanisms are elimi- nated ; the highest speed may be ob- tained and controlled especially to be desired in direct connection to dynamos; multiple discharge jets (or explosion pockets) may be arranged, as in the Pelton wheel ; the force of the explosion may be most directly utilized in a tan- GAS AND OIL ENGINES. 489 gential manner ; the internal friction will be reduced to a minimum ; the best opportunities will be presented for reg- ulating against the rapidly varying loads of electrical supply service ; and, probably, a greatly increased economy will result in the use of gas. 1 ' In matter of speed regulation, gas engines have had an unenviable reputa- given speed, at which load there is the least expenditure of gas per horse-power per hour. In this way it is possible to establish a very satisfactory basis for rating gas engines, that is, by their most economical performance. If gas engines could be tested and the curves of performance plotted, the whole gas- engine business would at once be placed FRONT VIEW OF THE VAN DUZEN GASOLINE TRACTION ENGINE. tion, more due to the inherent difficulties of control than to any lack of inventive ability along this line. Always single- acting, frequently run at low speeds, and sometimes with rapidly varying loads, it is not difficult to understand that during one or more strokes the supply of gas may be entirely omitted, and the unusually heavy fly wheel drawn upon to meet the periodic variations in the supply of energy. " Respecting the conditions of maxi- mum economy in the use of gas, it has been found that there is a certain best load, for any given engine running at a on as satisfactory and substantial a basis as is now the case with turbines. The establishment of such a gas-engine test- ing plant is urgently needed. It would go far towards giving much needed ad- ditional encouragement to well-directed efforts in the development of the gas engine, as well as serve to forestall fruit- less attempts in the same line." Mr. W. Lawrence Wildy, represen- tative of Messrs. Richard Hornsby & Sons, of Grantham, England, builders of the Hornsby- Akroyd oil engine, said : " Most of you know, doubtless, that the producer is an ordinary cylin- 490 CASSIER'S MAGAZINE. LOCOMOTIVE CRANE, WORKED BY A ROOTS OIL ENGINE. BUILT BY CLARKE'S CRANK AND FORGE CO., LTD., LINCOLN, ENGLAND. drical vessel lined with fire brick, and more or less intricate in shape, accord- ing to the inventor's idea of what his patent is, and with certain cooling sur- faces, or heating surfaces, or conducting surfaces, or something ; but you will find 150,000 patents in the patent journal, doubtless, and they have all got something about them. But the simplest producer I have ever used was a column of fuel about 10 feet high. The fuel we used was coke the coke which after distillation of the gaseous product was a residue which went to make the cost of the production of gas a mere cipher to the corporation running that gas concern. In Leeds, where I had my experience principally, the gas which was distributed through the houses cost nothing in the holder it was all profit. I have seen the figures, and I have gone into it with the chair- man of the Gas Committee of the Leeds Corporation, and it is a fact that it was a decimal short of nothing in the holder. " The by-products from making the bituminous gas were so valuable at that time, that they paid all the expense, in- terest and depreciation of plant, and the gas in the holder cost nothing but dis- tribution and collection of accounts. We were using enormous quantities of gas for welding steel tubes. We make tubes of varying diameters from 20 inches to 60 inches, and these varied in thickness from W to ^, and we welded these with the ordinary coal gas, and our gas bill ran from ^6006 to ^7000 a year. I got hold of this water-gas process, as it was used in Germany at the time, and I saw that it afforded a very good heating medium, very cheaply produced, and we went in for a plant there. The plant was a mag- nificent success, so far as we were con- cerned. It reduced our gas bill fiom between ^6000 and 7000 to just over ^1000 a year fuel, interest, de- preciation, labour, distribution every- thing concerned came just over ^1000 a year, or something under one-sixth of what we paid before. The gas cost us on an average about three pence half- penny per 1000 cubic feet. We made GAS AND OIL ENGINES. 491 only water gas, but we got no by-prod- ucts, and it therefore cost us something in the holder. In the water-gas busi- ness there are no by-products. "In the oil engine we have a machine which works with the ordinary petroleum of commerce, that is, any of the lighting oils which are in the market. It will also work with the heavier oils up to the specific gravity of .9, and it will work with an oil having a flash point of any- thing that the ordinary oils have, and up to 320 Fahr. is a pretty strong oil. The process through which this oil goes to produce its power is as follows : The engine is provided at the back of the cylinder with a small cylindrical cham- ber, which we call the vapourizer. On to this vapourizer is fixed a valve cham- ber, which really holds two valves, and which are the governour valves of the . engine; the one opens inward to the vapourizer, the other opens by the ac- tion of the governour outward, and, through a small pipe, conveys any oil which is not required, back into the tank from which the pump has drawn it. The rest of the construction of the engine, so far as its communicating the power imparted to it is concerned, is almost identical with the gas engine a trunk piston and connecting rod, and crank shank ; on the crank shaft a pair of skew wheels, the skew wheels driving a shaft almost identical again with the gas engine which shaft communicates motion, first, to the governours, and then to two valves, one for the air inlet, and the other for the exhaust ; the air inlet cam, at the same time, operates a small pump, from ^ to i % inches in diameter, according to the power of the engine to be developed, and this pump has a stroke which can be adjusted by the regulation of the screw that is, the oil pump so that the amount of oil which is injected into the vapourizer is exactly in proportion to the power the engine requires. Suppose you are running the engine at half power, you run the pump at half stroke ; if you are running the engine at full power, you run the pump at full stroke, that is, it you know you are going to do so. But A CROSSLEY OTTO GAS ENGINE AND AIR COMPRESSOR COMBINED. 49 2 CASSIE&'S MAGAZINE. A CROSSLEY OTTO PORTABLE GAS ENGINE. if you are running the engine at full power, and throw oft half the machines, the governour will do that, but the effect will not be so perfect as if you, know- ing what you want, reduce it yourself. The exhaust valve has a double cam, very similar to that of the gas engine, by which a portion of the compression can be released when starting the engine. Now, in operating the engine you be- gin by heating the vapourizer with a lamp an ordinary paraffin lamp with a circular wick to which a small fan is attached, producing, for the time being, a little petroleum forge. It takes from five to ten minutes to heat that vapour- izer. The only process is to fill the lamp and turn the fan handle. As soon as it is hot enough, you can turn your fly wheel, and your engine goes off at full cock ; it is ready immediately, and it goes off at full power then and there, governing itself. The continual com- bustion of the oil in the vapourizer re- stores to the vapourizer the heat which has been extracted by the vapourization of the oil and the heating of the air necessary to produce the subsequent explosion. ' ' These engines have been running continuously for two months, day and night, without stopping, without any hitch whatever, and the higher the work that is taken out of the engine, up to full power, the better the engine works. At very low powers the engine will want a little nursing, perhaps, but at full power she will work right along. We start our engine at 5.30 in the morning, and the men come in at six o'clock, and she is never looked at again, except when the man goes in at dinner time and oils her, and at half- past five, when he goes to stop her, and there is no outside flame, no ex- posed red heat or dangerous flame ot any sort about the engine." Asked what he meant by nursing, Mr. Wildy said that if the engine had to run light for five or six hours, which probably no sane man would do under ordinary circumstances, it is possible that he may want to put a little brake onto the engine or some- GAS AND OIL ENGINES. 493 thing of that sort to put a little work on her. Asked if there was any residuum in the cylinder, he said: "None what- ever. We have run for two months and there was not as much as you could wipe off with your hand. ' ' The consumption runs about seven- eighths of a pint of American daylight or water- white per horse-power on all sizes of engines. It runs a little lower, but only a little lower, on the larger engines than on the smaller ones. The very small ones will run on a pint. There is greater loss owing to the friction of the engine itself. I am giving you the brake horse- power, not indicated horse-power. We sell the engine on the power which the purchaser is going to get off the fly " The pressures in the oil engine are rather lower than in gas engines. In the Scotch gas I have had as much as 210 pounds initial pressure in the gas engine. The consequence is that the terminal pressure is so high that the ex- haust becomes noisy." The following discussion was con- tributed by Mr. Paul Winand, superin- A VAN DUZEN PORTABLE GASOLINE ENGINE, SAW AND PUMP COMBINED. wheel. He doesn't care what the power is in the cylinder. A 16 horse-power engine uses just .8 of a pint. " In Russia they are adopting these engines and we cannot keep pace with them. With us in England it is a mat- ter of consideration, because the oil which I understand you give about 7 cents a gallon for, costs us about 6 pence half-penny a gallon. They are doing wonderfully well with the engines over there. Every class of power-user is adopting them, to the rejection of all steam engines, up to 50 or 60 horse- power. They are in the hands of stablemen, gardeners, coachmen, all sorts of people, who, after they are once instructed, know what to do. tendent of the Otto Gas Engine Works, Philadelphia, U. S. A. :- ' ' Concerning gas lighting by incan- descent burners, I know by actual ex- periment that the temperature obtained from producer gas is not sufficient for the purpose. On account of the large percentage of inert gases which it necessarily contains, it is not even economical to enrich it for lighting pur- poses. However, by reason of the cheapness of the power obtained from this gas, electric lighting is generally the best possible way of providing light in such an installation. Pure water gas, though it can well be used in incandescent burners, is more ex- pensive per heat unit, and, on the 494 CASSIER'S MAGAZINE. whole, cannot compete with producer gas. " It is generally thought that by in- creasing the number of impulses, the gas engine can be greatly improved as far as regularity of motion is concerned. This is only an argument of relative value, however, as the question resolves itself to this : ' ' Whatever the number of impulses may be, there must be fly wheels of sufficient momentum to produce the desired degree of regularity. Now, is it cheaper, more economical and gener- ally preferable to have a simple engine with a large amount of momentum, or a more complicated one with smaller fly wheels? The same regularity can be obtained in all cases, and it has not been proved that a simple engine of sufficiently high speed is not the more preferable solution. Considerable ex- perience in this line has shown to me that it would be decidedly wrong to complicate the construction in order to get more than one impulse for each rev- olution. I should wish to emphasize the point made relative to the use of fuel gas for industrial heating purposes concurrently with its use for power. The advantages of gaseous fuel when applied not only on a large scale, as for metallurgical operations, but in smaller apparatus of various kinds, are being gradually recognized. ' ' A set of engines at Danbury, Conn. , were built by the Otto Gas Engine Works with the provision that they could be operated indiscriminately by producer gas or by illuminating gas. The latter gas having about six times the heating value of the former, it will be easily understood that a compromise had to be resorted to in the construc- tion, the result being that the engines do not give the best possible efficiency in either case. Engines built solely for producer gas would give better results. " Since steam is used in the Danbury plant for various purposes, it was quite natural to employ a small steam engine for starting the gas engines. The large engines built now by us are provided with a self-starting device which renders the use of auxiliary power unnecessary and greatly enhances the convenience of operating the plant. " The efficiency of a plant depends on the choice of the units of power, and perhaps a better result could be obtained in this case, if the units were differently selected. It should also be borne in mind that the producer used is large, and would be capable of furnishing gas for a greater amount of power, especi- ally if the load factor was more favour- able as it would be, for instance, in the operation of a mill or of a water-works, and I might well state here that gas power is being used extensively in Europe for the last named purposes. ' ' Up to this date it has been custom- ary to use a steam boiler in connection with the producer. This is not a necessity, however, and we operate in our works a producer plant without boiler. The necessary amount of water vapour which passes with the air through the producer is generated at atmos- pheric pressure by means of the waste heat of the gas as it leaves the producer. There is thus no additional fuel used for producing steam, and, besides, the operation of the apparatus is rendered almost automatic. " Despite statements to the contrary, oil engines have been manufactured in the United States for several years, and considerable effort has been made for their introduction. We ourselves are fully prepared to begin their manufact- ure if a sufficient demand should arise. But in view of the fact that gasoline en- gines are so much preferable in most every respect, it is not surprising that the demand for oil engines should be so small. Gasoline engines have all the advantages of gas engines, and in some of those built in the United States to-day the provisions for safety are so absolute that the insurance companies have no objection to their use. Besides the objectionable smell which seems in- separable from the oil engine, there is the objection of its not being ready for starting at a moment's notice. Oil en- gines are naturally wasteful when run- ning at partial and variable load. This is due to the fact that the proper de- GAS AND OIL ENGINES. 495 THE DAIMLER GASOLINE MOTOR CARRIAGE WHICH WON THE FIRST PRIZE IN THE PARIS ROAD CONTEST. gree of temperature is not maintained at the different loads which occur in practice. When a continuous external flame is used for maintaining this tem- perature the fuel consumed in this flame decreases the efficiency at reduced loads. ' ' The oil engine described by ;Mr. Wildy was exhibited at the World's Fair. In this engine the ignition of the charge depends on the temperature of the chamber, which is left uncooled at the rear. The temperature of this chamber, and consequently the time of GAS ENGINE, BUILT BY MESSRS. ROBEY & CO., LTD., LINCOLN, ENGLAND. 49<5 CASSIER'S MAGAZINE. ignition vary with the load, and this circumstance produces an additional variation of the efficiency with the load. " Oil engines are naturally somewhat more complicated, more expensive, and less convenient than gasoline engines, and unless there be a marked difference in the prices of the two fuels, the latter would seem preferable in most cases." Concerning oil engines generally, and particularly the already-mentioned Hornsby-Akroyd engine, built in Eng- land by Messrs. Richard Hornsby & Sons, of Grantham, and in America by the De La Vergne Refrigerating Ma- chine Co., of New York, Mr. Geo. Richmond has sent us the following : ' ' The term oil engine is not infre- quently used, in a very loose manner, to describe a variety of engines in con- nection with which oil is used as a fuel. Steam engines in which steam is generated by liquid fuel are sometimes called oil engines. Gas engines, for which the gas is prepared on the spot by carburetting oil with naphtha or gasoline, are also improperly called oil engines. The term is properly re- stricted to an engine using a heavy oil from which gas cannot be made without the application of heat. " As a thermal machine, the oil en- gine stands about on a par with the gas engine, and both are in this respect very much superior to the steam en- gine. The gas engine, however, is more costly to run when illuminating gas is used, for the reason that the gas companies charge a very much higher price per thermal unit in the form of gas than the coal merchant does for the same amount in the form of coal. The oil engine is cheaper than the gas en- gine in running for the reason that the cost per thermal unit in the form of oil is very much less than the cost of the same in illuminating gas. " The oil engine really dates as far back as the gas engine, but while the latter rapidly reached a practical and THE HORNSBY-AKROYD OIL ENGINE, BUILT BY MESSRS. R. HORNSBY & SONS, LTD., GRANTHAM, ENGLAND, AND THE DE LA VERGNE REFRIGERATING MACHINE CO., NEW YORK. GAS AND OIL ENGINES. 497 economic position, the former has not been put into an acceptable shape until quite recently. While an American can claim the honour of producing the first practical oil engine, its develop- ment was left to Europeans. Brayton, in 1872, patented and constructed at Exeter, in the United States, an engine using a heavy oil. A careful trial of a 5 horse-power, American Brayton pe- troleum engine was made at Glasgow by Mr. Dugald Clerk in 1878. The mean pressure was 30.2 pounds per square inch, diameter of cylinder 8 inches, length of stroke 12 inches. The engine made 201 revolutions per minute, and the consumption of petroleum was 2.16 pounds per indicated horse- power per hour. Much of the total power devel- oped was absorbed in driving the air and petroleum pumps, or, in other words, there was a good deal of friction. Dur- ing the trial the engine indicated 9.5 horse-power in the motor cylinder. Of this the pump absorbed 4. i horse- power ; therefore, the available horse- power was only 5.4. Only 6 per cent, of the total heat generated was utilized. ' ' The oil engine of the present day will convert into work 20 per cent, of the heat, and use somewhat less than one pound of oil per indicated horse- power. The chief practical objections to the gas and oil engines is the neces- sity of igniting the charge. The in- genious arrangement of Otto for trans- porting a flame into the body of the cylinder was in its day considered a triumph of mechanical skill. The dry heat to which the valve was subjected caused rapid deterioration and required frequent attention. This was followed by what is known as tube ignition, in which a tube is maintained at a red heat by a gas jet. The tube, like an incan- descent lamp, has a life-time of a certain number of hours, and is certain to split, sometimes sooner, sometimes later. The third mode of ignition is the electric spark, for which a battery and spark coil must be kept in good running order. This, however, gives less trouble than the contact points themselves within the cylinder, which are liable to become covered with incrustation. 5-3 " The two systems of tube and electric ignition have each their advocates who claim great things for them. The fact that there are innumerable patents for improving them would seem to indicate that the difficulties sought to be over- come are not entirely imaginary, of FIG. 3. HORNSBY-AKROYD ENGINE DIAGRAMS. + Indicates pure air. o Indicates oil. o Indicates products of combustion. which fact no one is better aware than the user of a gas engine. It is worth while recalling the fact that Beau de Rochas, who described, even if he did not use, the four cycle, now known under the name of Otto, recommends that the compression should be carried to a point at which the explosion would be automatic. " In the Hornsby-Akroyd engine we have the first example of a perfectly successful carrying out of this idea. The automatic explosion is not, in itself, diffi- cult to realize. The real difficulty is in securing this explosion exactly at the moment required. The introduction of valve-motion for timing the explosion 49 8 CASSSZX'S MAGAZINE. A PORTABLE HORNSBY-AKROYD OIL ENGINE. would naturally suggest itself, but it must be borne in mind that such valves would be subjected to a temperature considerably above red heat. The manner in which this explosion is ob- tained in the Hornsby-Akroyd engine is illustrated in Figs, i, 2 and 3, on the preceding page. The cylinder, it will be seen, is provided with an extension, communicating with the cylinder by a relatively narrow neck. This extension is unjacketed, and forms a retort in which the oil is vapourized. Nothing but oil in the liquid form is injected into the retort, and only air is drawn into the cylinder. The operation, which is perfectly clear from the cuts, is as follows : ' ' On the outer stroke of the piston, air is drawn into the cylinder, and oil is in- jected into the red hot retort. At the end of the stroke we have, therefore, in the retort, oil vapour, which is not explosive, and, in the cylinder, pure air, which is not explosive ; nor is there sufficient leakage from the one to the other to make either of the charges ex- plosive. On the return stroke of the piston, the air is forced from the cylin- der through the communicating neck into the retort. For a time the mix- ture of oil, vapour and air is too rich for explosion, but, as the piston progresses, sufficient air is forced in to make the mixture explosive. "Fig. 2 shows the mixing process, and Fig. 3, by the conventional marking, indicates that the explosion has taken place, and the cylinder and retort are filled with burned gases. This auto- matic explosion is found to take place exactly as the piston is making the re- turn stroke. " It will be noticed that the ignition takes place within the retort, the piston being protected by a layer of pure air. It is not claimed, of course, that these diagrams are exact representations ol what actually takes place within the cylinder ; nevertheless, their substan- tial correctness seems to be indicated by the fact that the piston rings do not be- come clogged with tarry substance, as is usually the case with this class of engine. This surplus air should ensure complete combustion, and that it is ac- complished is evident from careful analysis that have been made. 4 ' At the De La Vergne Refrigerating Machine Company's Works, at New GAS AND OIL ENGINES. 499 York, a Hornsby-Akroyd oil engine is running some wood working machinery for the pattern shop, and it is interest- ing to watch the promptness with which the governour adjusts the quantity of oil to the varying power which is taken off. The power will range from the full capacity of the engine to nothing, half-a-dozen times within ten minutes." A 30 H.-P. ENGINE, BUILT BY THE NEW ERA IRON WORKS, DAYTON, OHIO U. S. A., RUNNING ON NATURAL GAS. THE RECORDING GAUGE FOR STEAM PRESSURE. By Charles A. Hague. 'OR many years the writer has been deeply interested from a pro- fessional standpoint in the subject forming the title of this article. And, the argument is at least plausible, that if the steam engine in- dicator, revealing a diagram of the forces within the cylinder, is so necessary to the de- signing and operating of steam machinery ; if the knowledge ob- tained from the indi- cator card has been so potent in bringing the steam engine successively and successfully through its many stages up to its present prac- tical perfection, why should we not be equally well informed as to the con- ditions and operation of pressures within various kinds of vessels and pipes de- voted to the useful employment of all sorts of fluids and gases ? The fact really is, that it is absolutely necessary to be well informed as to the continuance, regularity and correctness for the purpose, of pressures where pressures are used. The steam engine is a more or less complicated machine, operated by a fluid, and often operating upon a fluid, the cause and effect of the energy used, so to speak, being subject to, and dependent upon, pressure. Could there be any folly greater, when searching and striving for economy in operation, than to remain voluntarily ignorant and in the dark, as to what has been, what is, and what probably will be? Regularity, that key-stone to the arch, is just as easy of acquirement, and much more satisfactory to live with, 500 than the uncertainty and irregularity too often prevailing in the management of organized effort involved in the uses of pressure and power. The tendency of the times in steam power is towards higher and higher pressures, higher ratios of expansion in engines, and con- sequently towards more expensive and complicated machinery. The study of the boiler designer to-day is to meet the demands for safety, high pressure and economical service ; and in propor- tion to the mechanical details involved, the boiler engineer's task is as arduous at least as that of the engine designer. Aside from the question of fuel econ- omy, the wear and strain upon the boiler by widely varying pressures within short spaces of time, even under the old regime of 70 pounds and under, was a great deal more serious than most people comprehended ; and to-day, with the load up to 150 and 200 pounds per square inch, the steadiness of the pull upon the metal is enhanced im- measurably in importance. The modern, internally-fired boiler, with its heavy shell, its thickness calcu- lated upon the relation between the elastic and ultimate tensile strength, and the load pressure to be used, is not proportionately as strong as its older and thinner-shelled brother. Materials decrease in -strength value, as the thick- ness increases ; they do not so readily resile, and the liability to permanent distortion of section is greater. It is a very reasonable theory that in cylin- drical vessels, when the pressure per square inch approaches the tensile strength limit, adding to the thickness will not increase the strength of the vessel. Reference to figures will aid the mind in grasping and appreciating the sort of experience a boiler plate goes through, UNIVERSITY QF CALIFORNIA LIBRARY