US1210897A

US1210897A - Gas-engine.

Info

Publication number: US1210897A
Application number: US1396715A
Authority: US
Inventors: Arthur Benj Browne
Original assignee: Individual
Current assignee: Individual
Priority date: 1915-03-12
Filing date: 1915-03-12
Publication date: 1917-01-02
Anticipated expiration: 1934-01-02

Description

A. B. BROWNE.

GAS ENGINE. APPLlcATloN mig 1uLY9, 1910. muawzn MAH. 12. 1915.

Patented Jan. 2, 1917.

4 SHEETS-SHEET ll Paal l www S S A f. v 0 @l une E s m W 1w A. B. BROWNE.

GAS ENGINE.

APPLICATION FILED 1ULY9, 1910 RENEWED MAR. l2. 1915.

laented Jam. 2, 1917.

4 SHEETS-SHEET 2.

LQQ?.

WTNESSES A. B. BROWNE.

GAS ENGINE.

APPLICATION FILED 1ULY9, 1910- RENEWED MAR. I2, I9I5.

Patented Jan. 2, 1917.

4 SHEETS--SHEET 3.

/NIf'Lvvo/e w@ fw.

A. s. BaowNE. GAS ENGINE.

APPLICATION FILED JULY 9, |910. RENEWED MAR. l2 l9l5- Patented Jan. 2, 1917.

4 SHEETS-SHEET 4.

WITNESSES este.

ARTHUR BENJ. BROWNE, 0F DENVER, COLORADO.

GAS-ENGINE.

Leidse?.

Specification of Letters Patent.

rammed aan. a, ieri.

Application filed July 9, 1910, Serial No. 571,247. Renewed March 12, 1915. Serial No.` 13,967.

To all whom it may concern:

Be it known that I, ARTHUR B. BRowNn, a citizen of the United States, and resident of Denver, in the county of Denver, State of Colorado, have invented certain new vand useful Improvements in Gas-Engines, of which the following is a specification.

My invention relates to an improved gas engine of' 'the constant-pressure-type, of high thermal efficiency.

The invention has been developed in concrete form sothat'it operates on a cycle comparable to an ordinary two-stroke cycle. By using this cycle the greatest etliciency will probably be obtained because every second stroke of a working piston is a power stroke; but the principles of the invention y may be adapted to other cycles.

The following are some of the principal characteristics of an engine embodying my invention: A body of. air at suitable pressure is contained in a storage space of suitable capacity. Air is supplied to the storage space byV compression in a working cylinder or cylinders and is returned from the storage space to the working cylinder or cylinders for use in the power strokes. Fuel is delivered to the air as it is re urned to the cylinder. An inlet port and valve for the returning air charge are constructed and arranged in connection with the fuel supply so that a certain portion of the air passes the fuel opening and receives the fuel charge and another portion of the air passes into the cylinder without being charged with fuel. By this means the actual explosive portion ofthe mixture may be made very rich and improved operative results and great economy are realized. The air compressed on the up stroke of the piston is preferably delivered to a cooler, which forms a part of the storage space referred to. This cooler reduces the" temperature of compression so that a larger volume of air may be compressed at given pressure than would otherwise be the case. This compressed charge in the preferred form of the invention is then conducted through a heater and the heat energy thus imparted to the charge insures its effective rexpansion in the cylinder. Heat is preferably supplied to the heatengrfrom the exhaust ports of the working cylinders so that the heat required to r'e-heat the charge is obtained without loss from what would otherwise be a waste product of the engine. A compression relief valve,.or unloading valve is also provided so that if the compression exceeds a certain predetermined amount, a portion of the air in the cylinder 1s discharged to the atmosphere. In this way after the desired compression pressure is reached, further work of compression and losses incidental thereto are avoided. Provision is made for placing the fuel under p'ositive pressure for its delivery to the compressed charge as it renters the cylinder. The mechanism for controlling the re-admission'of the charge to the cylinder is designed to permit an operative effect comparable to the cut-off in a steam engine and this mechanism in a preferred form is at the same time designed to permit the engine to run equally well in either direction of rotation. In' the specific embodiment of the invention, these results are obtained by the introduction of alink motion to control the inlet, or return valve.

'The advantages and characteristics of the invention will be further explained so far as is necessary in connection with the detailed description of the accompanying drawing, which shows an exemplifying structure in which the invention is embodied.

Figure 1 is a diagram of the whole mechanism. Fig. 2 is a vertical section of the engine in the plane of rotation of the crank. Fig. 3 is an elevation from the same viewpoint. Fig. 4 is a vertical section in the plane of the crank shaft. Fig. 5 is a horizontal section of the cylinder head. Fig. 6 is a longitudinal section of the heater and also represents one form in which the cooler may be constructed. Fig. 7 is an enlarged section of the head, as shown in Fig. 4.

Reference character 1 designates the cylinder on which is secured the head 2. 3 is the crank case. Within the cylinder is the piston 4 provided with a deflector 5 and connected to the crank 6 by connecting rod- 7 all of which may be as usual. The crank case is provided with an air inlet 8. An air passage 9 leads through the crank case and cylinder to port 10, which may be identified as the primary inlet port. 11 is the exhaust port. y

The head 2, as best seen in Figs. 1, 4 and 7, is divided to form a discharge chamber 12 and an inlet, or return chamber 13. The port between chamber 12 and the cylinder is closed by discharge valve 14 vprovided with the spring 15 and a port between chamber 13 and the cylinder is closed by return pet rod is driven from the crank shaft 6- by a mechanism which will be later described.

The discharge chamber has an opening 30 (see Fig. 2) from which apipe 31 (see Fig. 1) leads to the cooler 32. A principal purpose of the cooler is to enable a greater amount (weight) of air to be compressed in a storage space of reasonable size and With less Work of compression than Would be possible-Without the cooler, but the cooler is not indispensable andin some embodiments of the invention may be omitted With the probable sacrifice of some efficiency. A pipe 33 leads from the cooler to the heater 34 and a pipe 35 leads from the heater to opening 36 in return chamber 13. Pipe-35 may be provided with a throttle 37. In a portion of the cylinder head extending into the inlet chamber 13, are formed a series of connected fuel ducts 38, one end of Which leads to a smaller chamber 39 about the needle valve 19. The other end of this system connects by means of a pipe 40 with fuel pump 41, which is actuated by a downward extension of tappet rod 24. Fuel is supplied to the pump from a tank 42 by pipe 43.

A channel 44 communicating with the interior of the cylinder is formed in the portion of the head which carries the ducts 38, which lie around the channel. This is to amplify the supply of heat to the ducts for the vaporization of the fuel.

To limit the degree of compression of air in the Working cylinder, a port 50 is provided leading to the atmosphere through the opening 51. Unloading valve 52 is .provided with a conical portion 53 resting on a seat 54. The valve is also provided with l a. piston portion 55 moving in a small cylinder 56 formed in the head. A passage 57 leads from the discharge chamber 12 to the upper end of the piston 55. Valve 52 is provided with a spring 58 adjusted on the stem of the valve by a nut 59.

The valve tappet rod 24 is operated by

eccentrics

60 and 61 on the crank shaft. Eccentric 60 is for running in the direction shown by the arrow in Fig. 3 and follows the crank. eccentric is indicated by the angle COA. This angle may be varied, but a lead of the crank over the eccentric of 45 degrees is The lead of the cra-nk over the satisfactory and this angle of lead is shown in the drawing. Eccentric 61 is for running in the opposite direction and has a similar angular relation to the crank. on the other side indicated by BOC in the drawing. The eccentrics are connected by any suitable link motion 63 to a stud 64 ontappet rod 24. The link is controlled by a. lever 65 and as shown in Fig. 3 is in the position for running in the direction of the arrow with eccentric 60 giving its full motion to the tappet' rod. The angular position of eccentrics in relation to the shaft may of course be varied more or less as different conditions may require.

For starting, any suitable spark plugis inserted in the cylinder head through the opening 70. v

The engine operates in the following man` ner: Shortly after the piston starts down- Ward from the upper end of its stroke, eccentric 6Q raises tappet rod 24; the clearance between the tappet rod and the Valve rod is taken up, and the valve rod is raised against the resistance of spring 23, opening valve 16. Clearance between the tappet rod and the valve rod may of course be varied as conditions require. The storage space, comprising the cooler 32, heater 34 and pipes, contains air under suitable pressure. The storage space is of sufficient capacity to containa sufficient quantity of air under the desired pressure. Usually thestorage space will contain several times the compression volume of a Working cylinder l at the desired cycle pressure.

Upon opening the throttle 37 air passes from the storage system through chamber 13 past valve 16 into the cylinder. A portion of the air passes valve 16 tothe left of defiector 17. as seen in Fig. 4 and takes up fuel from the fuel port 18. Another portion and preferably the larger portion of the air passes around the other side of the valve and enters the cylinder unmixed with fuel. Before starting the engine, the fuel may be vaporized by heating the head ad jacent to the needle valve with a blow torch. The combustible charge thus introduced into the lcylinder is ignited by passing a spark compressed in the crank case 3 by the descent of the piston, rushes into the cylindery through the primary inlet port and the products of combustion are discharged at the same time through port 11, passing through pipe 11a to the heater 34. On the up stroke of the piston, the ports 1'0 and 11 are closed and air contained in the cylinder is compressed and discharged past valve 14 into the discharge chamber 12 and thence goes to the cooler 32 through pipe 31. A. certain portion of the heat of compression is removed from the air in the cooler and a large volume of air may therefore be compressed by the piston at a stated pressure. Asv the piston again descends, the return valve 16 is again opened and the compressed air in the storage system passes through the heater 34, reabsorbing heat therein, and reenters the cylinder, passing valve 1G, and is again ignited and so on.

After the engine has been in operation a short time, the ducts 38 in the head become heated and fuel supplied to the needle valve by the pump is thus vaporized.

The heater is supplied with hot gas from the engine exhaust and thus the compressed air is re-heated without economic loss.

The spring 15 of discharge valve 14 is lighter than the spring 23 of the inlet valve 16 so that air compressed by the piston is compelled to leave the cylinder through the discharge chamber. 'lf the piston compresses air to a pressure higher than that for which the system is adjusted, the pressure of air in the exhaust chamber acting on the upper end of piston 55 of the relief valve 52, forces the valve down against the resistance of its spring 58 and the remainder of the air in the cylinder is discharged directly to atmosphere through port 50 and Opening 51 without" further work of compression.

The faces of

conical valves

14 and 16 within the discharge and

inlet chambers

12 and 13 respectively are of larger area than the faces of the valves within the cylinder ano this greater area together with the effect of

springs

15 and 23 causes the valves to remain closed during the combustion of the charge in the cylinder, except when return valve 16 is held open by its operating means.

The heater is shown in section in Fig. 6. Compressed air from the cooler enters the heater at and passes through the central tube 81 to the upper' portion 82 of head 83. One or more tubes 84 connect head 83 with the other head 84 and one or more tubes 85 connect head 84 with the lower chamber 86 of head 83. Ports 87 lead from chamber 86 to the jacket 88 from which the compressed and heated air passes to the cylinder through opening 89. The course of the air through the heater is indicated by arrows. The central space 90 of the heater surrounds the

tubes

84 and 85 and hot products of combustion from the engine are introduced into this space through opening 91 and are discharged to the atmosphere through opening 92g;

Any suitable form of cooler may be used, for example, the intercooler of an air compressor. But a device similar t0 that shown in Fig. 6 may be employed. In this 'case compressed air from the cylinder enters at 80 and is discharged to the heater at 89, while cooling water is introduced at 91 and Llischarged at 9:2.

The engine may be reversed by pulling the link 63, as shown in Fig. 3, all the way over. The link also may be used as a cut oil" to vary the opening and closing of the return valve in a. manner which will be obvious from an inspection of the drawing.

1t will be evident that the moment ot' opening and closing of the return valu depends on the angular relation of the eccentrics to the crank and on the clearanwtA between the tappet rod 24 and valve rod 22. As a specific example of valve timing, when the eccentric has a lag or' 45 degrees behind the shaft as shown, the parts may be arranged so that the clearance between the ltappet rod and the valve rod is taken up when the crank is at its upper dead center. When the crank moves 45 degrees beyond the center, the valve is at its maximum open ing and when the crank is moved' 90 degrees beyond the center, the valve is Closed and in the further movement of the crank, the tappet rod 24 drops away from the valve rod and returns again into contact with it at the moment the piston again reaches its upper dead center. l/Vithout changing the angle of the eccentrics or their throw, the valve timing may be changed by varying the position of the stud 64 on rod 24 for which purpose a set screw 95 is provided. This adjustment of the stud varies the clearance between the tappet rod and valve rod and thus varies the moment of opening and closing the valve and also varies the amount of opening and closing of the valve, but this within reasonable limits, is of no consequence.

A two-stroke cycle has been described but evidently if it should be considered neces sary or desirable, other strokes might be introduced into the cycle. For instance, after a working stroke the nextreturn stroke of the piston might be merely for exhaust; the next forward stroke might be for the inspiration of a charge of air; the next return stroke would be for compression, and so on. But, ordinarily, the two-stroke cycle will evidently give greater eliciency because every second stroke is a working stroke, and this is probably the most advantageous form of the invention.

Crank-case compression has been described and this is a good representative way of supplying air to the primary inlet port 10 with sufiicient pressure to 4charge the cylinder; but other means of introducing air under sufficient pressure into the cylinder substantially at the end of the power stroke may be substituted. Y

It has been stated that this engine is of the constant pressure type. This description of the type of engine is not intended as a limitation but is descriptive of a principal general characteristic of the engine; that is, the pressure during all parts of the cycle is more nearly constant as distinguished from other engines, such as the ()tto type, in which the pressure varies very widely during a cycle. Such engines may be described as being, substantially, conlstant-vohuue engines.. The provision of a constant pressure engine substantially as here disclosed, with necessary mechanicall features. appropriate to the constant pressure cycle, introduces marked advantages in both thermal and mechanical etiiciency, and mechanical simplicity, as compared with constant volume engines and with previous developments in the line of constant pressure engines. Some of the important advantages of my constant pressure engine are, lower combustion temperatures, uniform pressure during the colnbustion period and therefore no sudden stresses requiring heavy mechanical construction, higher mean effective pressures' with lower maximum pressures, less necessity for close piston fit because of lower pressure, less lubrication diliculty, the possibility of effective governing extending -to the governing of each individual stroke if desired, as in a steam engine.

The thermal efficiency results mainly from the lower combustion temperatures and lower maximum pressures', with the wide range of temperature variation introduced by the cooler and heater when they are employed, and the economy of heat resulting from the use of the exhaust in the heater. rIhe constant pressure engines also are nearly perfect scavengers and the residual heat of the explosion adds to the eiliciency of the cycle, whereas constant volume engines are essentially non-scavenging eny gilles and the residual heat of the explosion tends to lower the efficiency of the follow'- ing compression.

In the operation of my engine, the expansive mixture is introduced and burnt-at substantially even pressure and thus the piston is, so to speak, pushed forward smoothly and without shock as compared with constant volume engines, in which the ignition'of the mixture is more like an explosion and the piston is, so to speak, struck with a violent blow at the commencement of the power stroke, the pressure thereafter falling off very rapidly.

Numerous other technical and operative advantages of my engine could be pointed out but they will be suiiiciently understood by persons skilled in the art without further explanation.

developing power from a combustible gaseous mixture. The steps in this cycle will be generally understood from the foregoing description of operation of the engine, but will be briefly repeated: Air is compressed to a suitable pressure and delivered to a cooler, where it is cooled and delivered to a heater; thence the air is delivered to the combustion chamber and supplied with fuel at or adjacent to the combustion chamber; the combustible mixture thus formed is burned expansively at approximately constant pressure; burnt products from the combustion chamber are supplied tothe heater to heat the air therein. Incidentally, inthe initial step of compressing the air further work of compression .is avoided after the desired pressure is reached. Describing the process somewhat more particularly in connection with suitable apparatus for its accomplishment, it is as follows: Air is introduced into a working cylinder above a piston and compressed by the upstroke of the piston to suitable pressure and delivered past a check valve to a I storage space which preferably consists'of a cooler and a heater to which the air goes in the order named, being first cooled and then reheated; the air is then returned to the working cylinder past a suitable controlling device, such as a valve, and at or adjacent the cylinder fuel is supplied to the returning air; the combustible mixture. thus formed is ignited and burned during substantially all or so much of the down stroke of the piston as may be desired; the hot-.products of combustion are discharged while a new charge of air is introduced into the cylinder; the hot exhaust is led to the heater to heat the air therein; incidentally, an unloading valve is preferably supplied, actuated by pressure in the storage space. to cause a discontinuance of the work of compression in the Working cylinder when the desired pressure is attained.

' It is evident that this thermoidynamic cycle or method may be accomplished with apparatus of quite widely differing charac. teristics, and I do not limit myself to details either in respect to the engine or# the method except as claimed hereafter.

I claim:

1. In a prime mover, the combination of a power cylinder, an inlet valve and a discharge valve therein, a cooler, a heater, a passage leading from the discharge valve to the cooler, a connection between the cooler and the heater, anda passage from the heater to the inlet valve.

2. In a prime mover, the combination of apower cylinder, an inlet valve and a discharge valve therein, a storage space including a cooler and a heater, a gas conduit for leading gases from the discharge lvalve to the cooler and heater in succession and back combinatlon of a power cylinder, a piston,

to the inlet valve, and means for supplying heat to the heater from burned gases exhausted from the cylinder.

3f In an internal combustion engine, the combination of a power cylinder, a piston, crank case compression means, the cylinder being provided with primary supply and exhaust ports near the outward end of piston travel, said primary supply port having communicationwith the crank case, a discharge chamber, a valve between-said chamber and the cylinder opening outward,` an inlet port, a valve therefor opening outward, a spring normally closing the discharge valve, a heavier spring normally closing the inlet valve, a cooler and piping leading from the discharge chamber to the cooler and from the cooler to the inlet valve.

4. In an internal combustionv engine, the combination of a power cylinder, a piston, crank .case compression means, the cylinder being provided with primary supply and exhaust ports near the `outward end of piston travel, said primary supply port having communication with the crank case, a discharge chamber, a valve between said chamber and the cylinder opening outward, .an inlet port, a valve therefor opening outward, a spring normally closing the discharge valve, a heavier spring normally closing the inlet valve, a cooler, a heater and a conduit leading in order, from the discharge chamber to the cooler to the heater and to the inlet valve.

5. In an internal combustion engine, the

crank case compression means, the cylinder being provided with primary supply and exhaust ports near the outward end of pis` ton travel, said primary supply port having communication with the crank case, a discharge chamber, a valve between said chamber and the cylinder opening outward, an inlet port, a valve therefor opening outward, a spring normally closing the discharge valve, a heavier spring normally closing the inlet valve, a cooler, a heater, a conduit leading in order from the discharge chamber to the cooler to the heater and to the inlet valve, a fuel port opening adjacent to the seat of the inlet valve, and mechanical means for opening the inlet valve shortly after the piston reaches the inward end of its stroke.

6. In an internal combustion engine, the combination of a power cylinder, a piston, crank case compression means, the cylinder being provided with prima-ry supply and exhaust ports near the outward end of piston travel, said primary supply port having communication with the crank case, a dischargechamber, a valve between said charnber and the cylinder opening outward, an inlet port, a valve therefor opening outward, -a spring normally closing the discharge valve, a heavier spring normally closing the inlet valve, a cooler, a heater, a conduit leading in order from the discharge chamber to the cooler to the heater and to the inlet valve, a fuel port opening adjacent to the seat of the inlet valve, the inlet valve being provided with a flange on its inner face, and mechanical means for opening the inlet valve shortly after the piston reaches ders, a storage space including a heater,

means for compressing a body of air in a working cylinder and transferring substantially all of said air to the storage space, means for supplying heat to the heater from the exhaust of a working cylinder, means for returning air from the storage space to a working cylinder and means for supplying fuel to the returning air.

9. In an internal combustion engine, the combination of one or more working cylinders, a.V storage space comprising a cooler and a heater, means for compressing a body of air in a working cylinder' and transferring it to the cooler and thence to the heater, means for returning said air to a working cylinder and means for supplying fuel to the returning air.

l0. In an internal combustion engine, the combination of one or more working cylinders, a cooler, a heater, means for compressing a body of air in a working cylinder, means for delivering a major part of said air to the cooler and heater successively, means for returning air from the heater to a working cylinder, and means for supplying fuel to the returning air.

l1. In an internal combustion engine, the combination of one or more working cylinders, a cooler, a heater, means for compress ing a body of air in a working cylinder, means for delivering a major part of said air to the cooler and heater successively, means for supplying heat to the heater from the exhaust of a working cylinder, means for returning air from the heater to a working cylinder, and means for supplying fuel to the returning air.

`12. In an internal combustion engine, the combination of one or more working cylinders each having crank case compression means communicating with said cylinder, an

eXhaust port for products of combustion. a discharge port and valve for air, and an inlet port and valve, a storage space connected with the discharge valve of one of the working cylinders to receive compressed airl therefrom, a connection between the storage space and the inlet valve of one of the Working cylinders, and means for supplying fuel to air returning to a Working cylinder.

13. In an internal combustion engine, the combination of one or more working cylinders, a storage space, means for compressing a' body of air in a Working cylinder and delivering a major part of said air to the storage space, means for returning air from the storage space to a Working cylinder, means for adding fuel to said air adjacent to the cylinder, and an unloading valve to relieve the Work of compression. v

14. In an internal combustion engine, the combination of one or more Working cylinders, a storage space including a heater, means for compressing a body of air in a working:| cylinder and delivering substantially all of said air to the storage space, means for supplying heat to the heater from the exhaust of a Working cylinder, means for returning air from the storage space to a Working cylinder, means for supplying fuel to the returning air, and a relief valve to limit compression pressure.

15. In an internal combustion engine, the combination of one or more Working cylinders, a storage space comprising a cooler and a heater, means for compressing a body of air in a working cylinder and delivering it to the cooler and thence to the heater, means for returning said air to a Working cylinder, means for supplying fuel to the returning air, and a relief valve to limit compression pressure.

16. In an internal combustion engine, the combination of one or more Working cylinders, a cooler, a heater, means for compressing a body of air in a Working cylinder, means for delivering a major part of said air to the cooler and heater successively, means for returning air from the heater to a Working cylinder, means for supplyingA fuel to the returning air, and a relief valve to limit compression pressure.

17. In an internal combustion engine, the combination of one or more Working cylinders, a cooler, a heater, means for compressing a body of air in a Working cylinder, means for delivering a lnajor part of said air to the cooler and heater successively, means for supplying heat to the heater from the eX- haust of a working cylinder, means for returning air from the heater to a Working cylinder, means for supplying fuel to the returning air, and a relief valve to limit compression pressure.

18. In an internal combustion engine, the combination of one or more Working cylinders each having crank case compression means communicating With said cylinder, an exhaust port, a discharge port and valve for air and an inlet port and valve, a storage space connected with the discharge valve of one of the Working cylinders to receive compressed air therefrom, a connection between the storage space and the inlet valve of one of the Working cylinders, means for supplying fuel to air returning to a Working cylinder, and a relief valve to limit pressure.

19. In anl internal combustion engine, the combination of one or more Working cylinders, a storage space, a discharge valve for delivering air from a Working cylinder to the storage space, a return valve to control return of air to the cylinder from the storage space, means for supplying fuel to the returning air substantially at the point of entry into the Working cylinder, means for operating the return valve, and means for regulating the time of closing of the return valve to produce a variable cut-off.

20. In an internal combustion engine, the combination of one or more working cylinders, a storage space containing a considerable volume of air at substantially constant pressure, means for compressing a body of air in a working cylinder and transferring a major part of said air to the storage space, means for returning air from the storage space to a Working cylinder and means for adding fuel to said air adjacent to said cylinder and burning said fuel at substantially constantY pressure.

21. In an internal combustion engine, the

combination of one or more Working cylinders, a storage space, meansv for compressing a body, of air in a Working cylinder and delivering a major part of said air to the storage space, means for returning air from the storage space to a Working cylinder, means for adding fuel to said air adjacent to the cylinder, and an unloading valve to prevent further Work of compression after pressure in the storage space reaches the del sired cycle pressure.

22. -In an internal combustion engine, the combination of a Working cylinder, a storage space containing a considerable volume of air at substantially constant pressure, a discharge valve in the cylinder communicating with the storage space, a return valve controllingreturn lof air from the storage space to the cylinder, means for operating the return valve and means "for supplying fuel to the returning air adjacent to the return valve, the pressure in the cylinder during the Working stroke being maintained at substantially the same pressure as that in the storage space. v

23. In an internal combustion engine, the combination of a Working cylinder, a storage space containing a considerable volume compression Larose? `means for supplying fuel to the returning air adjacent to the return valve.

24:. In an internal combustion engine, the combination of one or more working cylinders, a storage space, means for compress ing a body of air in a working cylinder and delivering a major part, of said air to the storage space, means for returning air from the storage space to a working cylinder means for adding fuel to said air, an unloading valve to connect the compression space of a cylinder with atmosphere and means actuated by pressure in the storage space to open the unloading valve when a certain compression pressure is reached.

25. In an internal combustion engine, the combination of one or more working cylinders, a storage space, means for compressing a body of air in a working cylinder and delivering a major part of said air to the storage space, means for returning air from the storage space to a working cylinder, means for adding fuel to said air adjacent to the cylinder, a normally closed unloading valve to connect the compression space of a cylinder with atmosphere and means actuated by pressure in the storage space to open the unloading valve when a certain compression pressure is reached:

26. A thermo-dynamic cycle consisting in compressing air, delivering it to a storage space comprising a cooler and a heater, successively cooling and heating the air while in the storage space, delivering the air to the combustion chamber and supplying fuel to the air after its initial compression, and burning the combustible mixture in the combustion chamber at substantially constant pressure.

27. A thermo-dynamic cycle consisting in compressing air, delivering it to a storage space comprising a heater, heating the air While in the storage space, delivering the air to a combustion chamber, supplying fuel to the air after its initial compression, burning the combustible mixture in the combustion chamber at substantially constant pressure, and supplying the hot products of combustion from the combustion chamber to the heater to heat the air therein.

28. A thermo-dynamic cycle consisting in compressing air, delivering it to a storage space comprising a cooler and a heater, successively cooling and heating the air while in the storage space, delivering the air to a combustion chamber, supplying fuel to the air after its initial compression, burning the combustible mixture in the combustion chamber at substantially constant pressure, and supplying the hot products of combustion from the combustion chamber to the heater to heat the air therein.

29. A thermo-dynamic cycle consisting in compressing air in a Working cylinder, delivering the air to a storage space comprising a cooler and a heater wherein the air is successively cooled and heated, returning the air to the working cylinder with the addition of fuel adjacent to the cylinder and burning the combustible mixture thus formed in the working cylinder at substantially constant pressure.

30. A thermo-dynamic cycle consisting in compressing air in a working cylinder, delivering the air to a storage space comprising a heater wherein the air is heated, returning the air to the working cylinder with the addition of fuel adjacent to the cylinder, burning the combustible mixture thus formed in the working cylinder at substantially constant pressure, and delivering the products of combustion from the working cylinder to the heater to heat the air therein.

3l. A thermo-dynamic cycle consisting in compressing air in a working cylinder, delivering the air to a storage space comprising a cooler and a heater wherein the air is successively cooled and heated, returning the air to the working cylinder with the addition of fuel adjacent to the cylinder, burning the combustible mixture thus formed in the working cylinder at substantially constant pressure, and delivering the products of combustion from the working cylinder to the heater to heat the air therein.

32. A thermo-dynamic cycle consisting in compressing air in a working cylinder, discontinuing the work of compression when the desired pressure is reached, delivering the air to a storage space comprising a heater wherein the air is heated, returning the air to the working cylinder with the addition of fuel adjacent to the cylinder and burning the combustible mixture thus formed in the working cylinder at substantially constant pressure.

ARTHUR BENJ. BROWNE.

Witnesses:

ASHTON F. CARTER, D. E. Oscoon.