US922613A - Internal-combustion engine. - Google Patents

Description

. UNITED STATES PATENT OFFICE.

CHARLES DAVID MCCLINTOCK, OF- OAKLAND, CALIFORNIA, ASSIGNOR OF ONE-HALF TO SAMUEL RUSSELL BOGUE, SAN FRANCISCO, CALIFORNIA.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented May 25, 1909.

Application filed June 23, 1908. Serial No. 439,957.

ioned wall of the combustion chamber, of-

means for increasing and decreasing theresistance of said Wall and allowing it to move during the compression of the charge.

In practice my invention will be carried out by a construction in which the usual rcciprocating piston, here called the working piston, acts in conjunction with another reciproeating piston, here called the air piston, both pistons being adapted to work in the same cylinder, or in separate cylindersconnected' to each other by a pass-Way or port, the air iston being adapted to separate the usual c earanee space into two parts; that part 'between the two pistons being here called the combustion chamber, and that part between the air iston and the lixed ead of the cylinder bemg here called the air chamber.

In connection with the several results of this type of internal combustion engine, to-

Wit, to thoroughly scavenge or clear the combustion chamber of the non-combustible or Waste products of each explosion before the introduction of the fresh charge of explosive mixture for the next explosion 3 to provide an air chamber affording an elastic-cushion to receive the impact or percussion effect of the explosion of the charge (which occurs before the end of the compression stroke of the Working piston) and thereby greatly lessen the back pressure 0n the Working parts of the engine, and at the same time, reduce vibration; and to store up the energy of the impact or percussion effect of each explosion in this air chamber, in the form of compressed air to be used immediately thereafter to perform Work (through the medium of the free moving air piston and the gases in the combustion chamber) on the working piston of the engine, the object of my invention is to regulate the pressure of air in the air chamber by means under-- control of a suitable governor', or by hand, in such a way as to vary the volume of the combustion chamber or clearance space, as it is commonly called, at a certain pre-determined ratio to the quantity of explosive mixture taken into thc cylinder during the suction stroke. of the working piston; thus cll'ecting' the ignition of the explosive charge at nearly crmstant pressure for any quantity of the con'ibustible, Whether full clmrge or a fraction oll the full charge, and thereby obtaining nearly the same terminal or maximum pressure, with consequent economy of fuel for all practical variations, of the quantity ol" the explosive charge. This feature of variableI clearance, asl call it, also makes the engine controllable to a degree not possible with cngines burning their charge of explosive at constant volume and variable pressure in a combustion chamber of {xed volume, it having been found that the combustion of gases or explosive mixtures ol' air and oil-vapor in closed cylinders is greatly aided by compression before ignition, and, also, that a higher pressure is obtained by such combustion under pressure. This device aims to keep the pressure of ignition practically constant for all quantities of the explosive charge. The volume of each explosive charge is to be reg'ulated by the usual means of throttling, or by some suitable positive cut-oil mechanism controllable by the usual governor, or by hand. I attain these results by the mechanism illustrated in the accompanying drawings, in which Figure 1, is a vertical section of my internal combustion engine, the pistons beingat the end of their respective instrokes, this being their relative position at the instant of coinplete cxpulsion of the burned products of the previous explosion. Fig. 2, is a verticalsectior showing the relative position of the pistons at the instant of the explosion of the charge in the combusthm chamber. Z-.l is a sectional view showing the air piston in a chamber separate from the engine cylinder,V but communicating therewith.

The main cylinder 1, with its water spaces 2, its inlet valve 3 and inlet opening 4, its exhaust valve 5 and' exhaust opening its working piston 7 and co-acting connecting rod 8, and its port 9, are, substantially, the same, in arrangement and operation, as in other i1iternal-eonibustion engines.

ln Fig.A 2, the line A-B, marks, approximately, the top or outer end of an ordinary single acting' cylinder as in common use on internal combustion engines, and the portion of the cylinder shown in this figure above this line is, in'this form, an vextension of the cylinder Which provides forthe air piston v and the air chamberl 11. In adapting my invention to an ordinary single acting cylinder the com I prefer this form of extending or lengthening the cylinder, as shown, the piston 10 fittingf closely, buttfree to move therein, and being adapted to separate the air chamber 11, from the combustion chamber 12.

To the air iston 10, and co-acting there- With, is attac ed the guide rod or stem 13, Working in and closely fittin "the opening in the cylinder head 11,6. Attac ed to the'guide rod 13 isthe small/cylinder 17, thesame being threaded and screwed on the guide rod 13, and further secured by the lock nut 18. The fixed piston or collar 19 on the cylinder head 16 is adapted .to fit closely to the inner Walls ofthe small cylinder 17, forming the inclosed air s ace 20 which is desi ned to provide an elastic-cushion to check t e instroke of the air iston 10, and revent it from coming in vio ent contact With the Working piston 7. The small opening or port 2,1 connects the adjustable relief valve 22 with the air chamber 1 1, and the said relief valve is adapted to open automatically When the pressure in the air chamber 11 reaches a maximum for Which the relief valve has previously been set.

The object ofthe adjustment of the maximum pressure in the air chamber 11. is apparent by the following LetY it be assumed that the engine is just started, and the air in the air chamber 11 stands at the temperature and pressure of the atmosphere. It will be seen that the air in the air chamber 11 Will become heated as the engine warms up after starting andthe increase of ressure, due to the lair being confined, Will, y resisting the compression of the charge and reducing the volume of the clearance space, cause a higher pre-com ression oftheexplosive charge in liustion chamber 12. Thus, by adjusting the maximum pressure in 'the air chamber 11 by means of the relief valve 22, (which adjustment Will also fix the minimum pressure) a Wide range of pre-compression pressures may be had. This feature readily.

adapts the engines to the use lof different fuels, requiring different degrees of pre-compression for their proper combustion, and it also provides a means for adjusting the en- .gine to the use of'any one kind of explosive mixture in such a Way as to obtain complete 4 combustion and the maximum amount of for limitin the maximum Work for the fuel consumed.

' The relief valve 22 only provides a means ressure, as -by loosening t e spring by Whic it is adjusted, it will allow some of the air in the air chamber 11` to escape, and thereby reduce' both the maximum and minimum pressure; or by tightening-the s ring, the pressure in the air chamber 11 `Wil rise to the maximum pres# sure for which the relief valve 22 is set'before allowing any of the air in the air chamber to escape in the air' reservoirn hereinafter' described, thereby maintainin a higher precompression pressure in 4t e combustion chamber 12 by reducing its volume.

The action or operation of an internalcombustion en ine of this type, as far as described is as fol oWs z-On starting the engine Ilet it be assumed that the'Working piston. 7

immediately after the Working piston 74 starts on its first out-stroke. The opening of this inlet valve 3 admits the charge or explosive mixture which flovvs into the combustion chamber 12 as the Workin piston 7 recedes. This operation, When a ful charge of the explosive mixture is required, continues to the end of the first out-stroke, commonly called the suction stroke", at Which-point the inlet valve 3 closes and the Working iston 7 starts on its first in'stroke, common y called the compression stroke. It Will be noted that the air piston 10 remains stationary during this first out-stroke or suction stroke of the Working piston 7. NOW, at

the beginning of the first in-stroke or compression stroke gof the Working iston 7 the valves 5 and 3 b eing closed, the c arge in the combustion chamber 12 stands at approximately, the pressure of the atmosphere, and

Aas the piston 7 advances, the volume `of this charge is reduced .and its temperature increased, both bytheat-tendant compression, and by comin in contact With the heated Walls of the4 cyinder 1. and the pistons 7 and `10. These combined conditions cause a to move on its first outestroke, thereby compressing the air in the air chamber 11 and maintaining a practical balance of pressuresv in the air chamber 11 and the combustion chamber 12 throughout the compression stroke". Near the end of this compression stroke and When the proper pre-compression of the charge has been. attained the Vcharge is ignited, and explodes violently in the combustion chamber 12, causing an im.- mediate rise of pressure therein, 'which instantly forces ,the air piston 10 still farther f has int'o the air chamber 11 until a practical balance of pressures has again been reached in the two chambers. Let it be now assumed that the working piston 7 and the air piston 10 have reached the end of their res ective compression strokes, and that the ighest temperature of the burning charge and maximum pressure in both the combustion chamber 12 and the air chamber 11 have been attained. 1t should be remembered that the ultimate stroke of the air piston 10 is only about three-tenths of the stroke of the working piston 7 and that after the maximum precom ression in the combustion chamber 12 een reached, the greater part of the stroke of the air iston has been made; therefore, a very smal movement of the air-piston 10 at the time of the explosion of the charge is sufficient to greatly increase the pressure of the air in the air chamber 11,'and, also, that this slight movement of the air iston, caused by the explosion of the charge, as no material effect on the pressure or volume of the burning gases, the combustion chamber 12 now being comparatively large, and the air chamber 11 small. The compression and expansion of the air and the gases forming the ex losive charge, follow very nearly the law, 'lressure times volume equals a constant. its second out-stroke, commonly called the working stroke or impulse stroke, and

the pressure of the gases in the combustion.

chamber 12 immediately begins to fall as the f gases expand. At, the same time the compressed air in the air chamber 11 also begins to expand, always tending lto keep a ractical balance of pressure in the two cham ers, and driving the air piston 10 on its in-stroke. This expansion of gas and air continues throughout the working stroke. A

The air piston 10 may be considered as merely floating between the gases in the com- -bustion chamber 12 and the compressed air in the air chamber 11, and so gives to the Working piston 7 the stored up energy of the impact of the explosion of the charge, which is lost in all internal combustion en ines having a fixed or immovable cylinder cad, fand a combustion chamber of unvarying volume. No part of the force of the exploding gases is here lost, except the unavoidable loss of heat by convection and radiation throu h the walls of the cylinder; and the direct e ect of storing up the energy .of this impact by the use of these improvements, as herein described, is to maintain a higher mean pressure on the working piston 7 throu hout its working or impulse stroke. ow, the

second out-stroke or impulse stroke of the? working piston 7 has been completed, and the exhaust valve is'opened mechanically when the gases, still under a pressure greater than the atmosphere, rush out through the Now the working piston 7 starts on exhaust openinflr 6. This causes the pressure of the gases in t e combustion chamber 12 to fall to that of the atmosphere; and the air piston 10, being relieved of this pressure on,

the side next the combustion chamber 12 and impelled by the pressure of air in the air chamber 11, quickly completes its in-stroke. At the same time, and while the burned gases are flowing from the combustion-chamber, the working piston 7 makes its second instroke, commonly called the exhaust stroke, and at the completion of the stroke, the Working piston 7 and the air piston 1() are again in the position shown in Fig. 1, being then very close together, and practically effecting the complete expulsion of the burned or non-combustible products of the previous explosion.

vIt is not essential that the air `piston be located in an extension of the main cylinder, for in some cases it may be in a separate chamber 14 connected with the main cylinder by a passport 15, as shown in Fig. 3.

The foregoing description of the four phases of the Workin@ cycle only conteniplates the,` use of a ful charge of the explosive -mixture, from which 1s obtained the maximum amount of work which the engine is capable of delivering. Now, let us consider the main object' of the invention, namely; means for varying theclearance space in which the combustion of the fuel takes place, by means of which-a fraction of the full charge may be taken into the cylind'er and exploded at practically the same pre-com ression pressure as with a yfull charge, ut with a corresponding decrease of able volume of the combustion chamber in proportion to the charge taken in, byv the following means: At some convenient point on or near the main cylinder 1 of the engine, is placed the air-reservoir 23. This air reservoir may containatmospheric air under pressure from an air pum o erated by the en- 1gine (preferably), or y and, or it may be lled with the spent gases from theexhaust of the engine, which' will `give ythe necessary pressure, `Without a pump; orit may be filled with steam generated by the heat of the exhaust gases, or by a separate heater. Either air, spent gas or steam will work equally well for the purpose, provided the necessary pressure is maintained in ltheair reservoir I prefer to use spent gas from the exhaust as the simplest means to the desired end.

From the air reservoir 23 and connectingl :With the air chamber 11 of the engine, is a tube or pipe v'24 having an intervening air valve 25, and a check valve 26 adapted to control the flow of compressed air, lgas or steam'from the air reservoir to the air chamber. This air valve is to be automatically o erated by the usual governor, or by hand, t eobject being to increase the initialpressure of air, gas or steam in the air chamber at the same time with the corresponding de-v crease of charge taken into the Working cylp inder ofthe engine. The open-ing of this air valve may never be sufficient for an extreme change of charge from full charge to minimum charge else it might exceed the requirements of the more moderate changes of charge. It is rather intendedl to control, under moderate changesof charge at each explosion, or gradually for any radical or .extreme change, re uiring probably five or six full working cyc es of the engine to accomplish the complete change from full charge to minimum charge. Also leading from thel air chamber 11 is the pass-Way or port 27,v to Which is connected the auto-v matic relief valve 22, which is nothing more than the ordinarysafety pop valve common to all pressure service devices. This relief valve is adjustable to the re uir'ed maximum pressure of the exploding c arge in the com ustion chamber, which pressure Will also be present in the air chamber 11, and is adapted to open automatically when pressure into the air reservoir, and

this predetermined maximum pressure-has been reached, discharging the ove lus; of eepmg the maximum pressure in the air chamber at the desired point for all Working-conditions of the engine. Thus it Will be seen that by means of the air valve 25, and the .supply of air, spent gas or stream lowing In an internal combustion engine, and in combination With its Working piston, a second piston forming the opposing Wall of the combustion chamber, a pneumatic cushion behindsaid second-piston and means for in= creasing and decreasing the resistance of said pneumatic cushion and allowing said second piston to move during the compresn sion of the charge.

In testimony whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

CHARLES DAVID MCCLINTOCK.

Witnesses:

WM. F. BOOTH, D.,B..RIcHARDs.

Images