US 3886734 A
A continuous combustion engine wherein air or other compressible working fluid is initially compressed in a working chamber defined by a power cylinder and piston means movable in the cylinder with a cyclic motion which causes alternate expansion and contraction of the chamber, the compressed air is transferred to and heated at substantially constant pressure in a combustion chamber to produce a hot pressurized working fluid, this working fluid is returned to the same power cylinder to drive the piston means in its cyclic motion, and the spent working fluid is exhausted from the cylinder. Two inventive embodiments are described, one having an annular power cylinder and rotary pistons and the other having linear power cylinders and reciprocating pistons.
Claims available in
Description (OCR text may contain errors)
MM June 3, 1975 ABSTRACT A Primary E.\'uminer-Clarence R. Gordon Attorney. Agenl. or Fzrm-Bomard I. Brown A continuous combustion engine wherein air or other 133/347 compressible working fluid is initially compressed in a v Fflz 3/00 working chamber defined by a power cylinder and pis- 6()/3q 63 3951; 133/347 ton means movable in the cylinder with a cyclic motion which causes alternate expansion and contraction of the chamber. the compressed air is transferred to and heated at substantially constant pressure in a combustion chamber to produce a hot pressurized working 0 United States Patent Johnson l l CONTINL'OL'S COMBUSTION ENGINE I76] lmcntor: Richard G. Johnson, loll W. N-ll Palmdalc. Calif, 93550 2| Appl. No: 363.030
U.S. Cl. 60/3943]; 60/3963;
Field of Search References Cited UNITED STATES PATENTS 9 Claims. 1] Drawing Figures fluid, this working fluid is returned to the same power cylinder to drive the piston means in its cyclic motion. and the spent working fluid is exhausted from the cylinderi Two inventive embodiments are described one having an annular power cylinder and rotary pistons and the other having linear power cylinders and recip- PATHHEUJUIE 3 1975 SHEET PATENi EUJiH SHEET FULL POWER PART/AL POWER LOW POWER V4 R/ED POI? T/NG F/XED PORT/N6 INDICATOR D/A GAAM WORK/N6 CHAMBER COMBUSTION CHA M551? IDLE POWER CONTINUOUS COMBUSTION ENGINE BACKGROUND OF THE INVENTION 1. Field of the Invention:
This invention relates generally to engines and more particularly to a novel continuous combustion engine.
2. Prior Art:
Present day engines for automotive vehicles and other engine driven machines are internal combustion engines, that is engines of the type in which compression and combustion of a fuel-air mixture and expansion of the resulting combustion gas to produce work all occur in one chamber or cylinder.
This type of engine has numerous disadvantages which are so well-known as to eliminate the need for explanation. Suffice it to say that a major disadvantage of such engines resides in the high level of contaminants or air pollutants present in their exhaust emission. Because of these exhaust emissions and their polluting effect on the atmosphere, there is a current and ever increasing emphasis on developing both ways to reduce such exhaust emissions and new engine concepts to reduce or eliminate exhaust emissions.
A basic objective of the present invention is to achieve continuous internal combustion. Continuous combustion results in more complete combustion than intermittent combustion and complete combustion is a more efficient way to reduce exhaust pollutants than incomplete combustion followed by exhaust gas treatment In addition. internal combustion in that no heat exchangers are required. No vapor generator (boiler) or condenser is required and the engine becomes sim pler and more efficient.
The present invention shares the above advantages with the gas turbine engine which is well known in the art. However, the present invention has several important advantages over the gas turbine engine, and these include non-continuous or cyclic heat application to the moving, highly stressed parts of the engine as well as others.
Examples of modified engine designs which describe prior art in the field of the present invention are found in Patent Nos. 125,166; 151,468; 3,171,253; 3,488,952, 3,577,729.
SUMMARY OF THE INVENTION This invention provides an improved engine, similar to a Brayton cycle engine and referred to herein as a continuous combustion engine, which avoids many if not most disadvantages of a conventional internal combustion engine. The present invention uses a modified Brayton heat engine cycle but uses a new machine cycle. This distinction is made since any actual internal combustion engine is not a true heat engine in the sense that is not only transfers heat and work across its boundaries but also receives matter in the form of fuel and air and rejects it in the form of products of combustion.
This invention is essentially a positive displacement Brayton cycle engine which uses a unique machine cycle to provide continuous internal combustion but non-continuous application of hot gases to the moving parts of the engine. in the engine of this invention, air or other working fluid is initially compressed in a power cylinder, the compressed air is transferred to and heated at substantially constant pressure in a separate combustion chamber, and the resulting hot pressurized working fluid, is returned to the same power cylinder for conversion to work by expansion in the cylinder. To this end. the power cylinder contains piston means which defines with the cylinder working chamber means. The piston means is movable with a cyclic motion which causes alternate expansion and contraction of the working chamber means. The combustion chamber is separate from the working chamber means and contains means for burning a fuel to heat the compressed air at substantially constant pressure to produce a hot pressurized working fluid.
The power cylinder is provided with intake port means which receives the air or other working fluid being utilized, compression and power port means communicating the cylinder to the combustion chamber, and exhaust port means. Flow through these port means is controlled by valve means which open and close the port means in timed relation to the cyclic motion of the piston means in the power cylinder means.
During operation of the continuous combustion engine, the intake port means open to admit air to the working chamber means. This air is then compressed during subsequent contraction of the working chamber means. Following this compression, the compression port means open to admit the compressed air to the combustion chamber, where the air is heated at substantially constant pressure to produce a hot pressurized working fluid. This working fluid is then returned to the same or another power cylinder through the power port means to undergo expansion in the working chamber means and drive the piston means in its cyclic motion. After expansion, the spent working fluid is exhausted through the exhaust port means to complete one cycle of the engine.
Two different embodiments of the continuous combustion engine are described. One embodiment com prises a rotary piston power unit similar to that described in my US Pat. No. 3,807,368, entitled Rotary Piston Machine. In this form of the engine, the power cylinder is an annular cylinder. The power pistons travel around this cylinder and simultaneously undergo reciprocating motion toward and away from one another along the circular axes of the cylinder. The pistons define therebetween working chambers which undergo expansion and contraction as a consequence of this reciprocating motion of the pistons. The pistons also serve as valves for controlling flow through the port means of the power cylinder to and from the working chambers between the pistons.
According to a feature of this engine form, each cylinder port means comprises a pair of ports which open to the annular power cylinder at appropriate SICltES of the plane of the cylinder, that is the plane containing the circular axes of the cylinder, and are aligned to balance the pneumatic forces on the pistons.
During operation of the rotary piston embodiment of the continuous combustion engine, each work ng chamber undergoes a repetitive expansioncontraction cycle including an initial intake phase, a following compression phase during which the chamber contracts, a following power phase during which the chamber expands, and a final exhaust phase. The power cylinder ports are opened and closed by the pistons in timed relation to this cycle in such a way that during its intake phase, each working chamber receives air through the intake port, after which the air is compressed in the chamber during its compression phase. Near the end of this compression phase of each working chamber. the compressed air is expelled from the chamber into the combustion chamber through the compression port and undergoes heating in the combustion chamber. As each working chamber commences its expansion phase, the power ports are opened to admit hot pressurized working fluid to the chamber from the combustion chamber. This working fluid then undergoes expansion in the working chamber and exerts a driving force or torque on the pistons to drive the latter in their cyclic motion about the power cylinder. Following expansion, the spent working fluid is exhausted through the exhaust ports'to complete one power cycle.
The intake and exhaust phases can be implemented by using either a two phase or four phase working cycle of the engine. In the four phase cycle the working chambers expand and contract twice during each engine cycle and the intake phases take place while the working chambers are expanding. Conversely, the exhaust phases take place while the working chambers are contracting. In the two phase cycle the working chambers expand and contract only once during each engine cycle and the intake and exhaust phases occur simultaneously while the working chamber is near its maximum volume and while the intake and exhaust ports are both registering with the chamber. In this case the exhaust gas is forced out of the chamber by fresh incoming air which is provided by a scavanging means external to the engine. It will be immediately evident to those versed in the art that any of the various engine arrangements described in my US. Pat. No. 3,807,368 can be used as a continuous combustion engine with the addition of the combustion chamber, compressor and power ports and other elements to be described bet low.
The second described embodiment of the continuous combustion engine is a multi-cylinder reciprocating engine having linear power cylinders containing reciproeating pistons. These pistons define with the cylinder working chambers which undergo alternate expansion and contraction as the pistons reciprocate. Rotary valves, driven in rotation in timed relation to the reciprocating motion of the pistons are utilized to control the admission of air to the working chambers, expulsion of the compressed air from the chambers to the combustion chamber, admission of working fluid from the combustion chamber to the working chambers, and exhausting of spent working fluid from the working chambers.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section through a continuous combustion engine according to the invention;
FIG. 2 is a section taken on line 2-2 of FIG. 1',
FIG. 2A is an isometric view of the continuous combustion engine of FIGS. 1 and 2;
FIG. 3 is a partial sectional view showing details of the servo-mechanism portion of the engine of FIGS. 1 through 2A;
FIG. 4 is a fragmentary section view taken substantially at line 4-4 of FIG. 2;
FIG. 5 is a fragmentary sectional view taken at line 5-5 of FIG. 4;
FIG. 6 is a pressure volume diagram of the operation of the engine of FIGS. I through 3;
FIG. 7 illustrates a modified form of continuous com bustion engine according to the invention, utilizing a multi-cylinder engine;
FIG. 8 is an enlarged sectional view taken at line 8-8 in FIG. 7; and
FIGS. 9 and 10 are pressure-volume diagrams relative to the engine of FIGS. 1, 2 and 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1-6, there is illustrated a continous combustion engine 10 according to the invention. Engine 10 has a combustion chamber 12 containing means 14 for heating a compressed working fluid such as air to produce a hot pressurized working fluid and a power unit 15 in which the air is initially compressed and the hot pressurized working fluid expands to produce work. Power unit 15 has a power cylinder 16 containing piston means 18 which define with the cylinder working chamber means 20. The power unit 15 has an output shaft 21 to which the piston means 18 are connected by means 22 for effecting movement of the piston means in the power cylinder 16 with a cyclic motion which causes alternate expansion and contraction of the working chamber means during rotation of the shaft. The power cylinder has intake port means 24 for receiving intake air, compression and power port means 26, 28 communicating with combustion chamber 12, and exhaust port means 30 opening to atmosphere. Flow through these port means is controlled by valving means furnished by the piston means IS in timed relation to the cyclic motion of the piston means.
Briefly, the operation of the engine 10 is as follows. The intake port means 24 open to admit air to the working chamber means during expansion thereof. This air is then compressed during subsequent contraction of the working chamber means. Near the end of compression, the compression port means 26 open to admit the compressed air to the combustion chamber 12 where the air is heated at substantially constant pressure to produce a hot pressurized working fluid. This working fluid is admitted back to the power cylinder 16 through the power port means 28 and undergoes expansion in the working chamber means 20 to exert a driving torque or force on the piston means 18 to drive the latter in its cyclic motion, thereby driving the shaft 21 in rotation. After expansion, the spent working fluid is exhausted through the exhaust port means 30 to complete one cycle of the continuous combustion engine.
Referring now in greater detail to the particular continuous combustion engine selected for illustration, the power unit 15 shown is a rotary piston machine of the kind described in my U.S. Pat. No. 3,807,368. Power unit 15 has a generally flat circular housing 34 containing the power cylinder 16 which, in this instance, is a concentric annular cylinder. The housing has mounting legs 35. Shaft 2I is rotatably supported in the housing, concentric with the cylinder 16. This shaft extends be yond opposite sides of the housing and mounts a flywheel 39a and output pulley 39b. The shaft has an enlarged central land 40 providing thrust shoulders to restrain the shaft against endwise movement relative to the housing. The power cylinder port means 24, 26. 28, 30 comprise pairs of ports opening through opposite sides of the housing to the power cylinder 16 with the ports of each pair located opposite one another. to effeet balancing of the pneumatic forces on the power unit piston means 18. as explained later. The housing has intake and exhaust conduits 42, -13 communicating with the intake and exhaust ports 24, 30, respectively Compression and power passages 44, 4S communicate the compression and power ports 26, 28 to the combustion chamber 12.
Piston means 18 comprise four pistons spaced about the annular power cylinder 16. Pistons 18 form there between the working chamber means 20 which, in the illustrated engine, comprise four separate chambers.
Pistons 18 are connected to the power unit housing 34 and shaft 21 by the cyclic motion means 22 which, in this instance, comprises planetary gearing. This planetary gearing is so arranged that during rotation of the shaft 21, the pistons undergo a compound cyclic motion involving generally rotational motion of the pistons in one direction around the power cylinder 16 and reciprocating or oscillating motion of the pistons relative to one another along the cylinder axis. This oscillating motion of the pistons occurs in such a way that the working chambers 20 undergo alternate expansion and contraction as they effectively move with the pistons through the cylinder.
Planetary gearing 22 comprises a reaction sun gear 46 fixed to an inner wall of the housing 34in concentric surrounding relation to the engine shaft 21. Power cylinder 16 opens radially inward toward the sun gear 46 and has annular shoulders 47 along the edges of its inner side opening. Fixed to the engine shaft 21 within the housing 34 is a spider-like planet gear support 48. This gear support has arms 50 which extend radially outward through the inner side opening of the power cylinder into cavities in the pistons 18. Fixed in the outer end of each support arm 50, within the respective piston cavity, is a bearing 52 with its axis parallel to the engine shaft. A shaft 54- is rotatable in each bearing 52. Rigid in one end of each shaft 54 is a planet gear 56 which projects radially inward into meshing engagement with the sun gear 46. From this description, it is pparent that during relative rotation of the shaft 21, the planet gears 56 roll around the sun gear 46 and simultaneously undergo rotation of their individual central rotation axes.
Each planet gear 56 is connected by means 58 to its Pective piston 18 in such a way that rotation of the ear on its central axis imparts a longitudinal reciproeating or oscillating motion to the piston relative to th Planet gear. The particular connecting means shown comprise crank pins 60 parallel to and displaced from the central rotation axes of the planet gears 56 and rotable with these gears. These crank pins rotatabiy mount slides 64 which slide in slots or grooves 66 formed in the inner walls of the pistons 18. These slots of each piston are disposed in a common plane norma to the central axis of the power cylinder 16. From this description, it is evident that rotation of each planet r drives its piston in a back and forth oscillating motion relative to the gear.
Means 68 are provided for closing or sealing the inner side opening of the power cylinder 16 between the P tons 28 and hence the inner sides of the working chambers 21). Sealing means 68 comprise curved sealing plates 71) fixed to the central disc of the planet gear upport 48 opposite each combustion chamber 2t). These sealing plates may slide on and be disposed n fluid scaling r ln t th housing annular shoulders 47 or to the insides of the housing 34, or both, and extend endwise into fluid sealing relation with the inner sides of the adjacent pistons 18. The sealing plates are longitudinally dimensioned to remain in sealing relation with the adjacent pistons throughout the range of their longitudinal oscillating motion.
From the above description. it is apparent that during rotation of the power unit shaft 21, the pistons 18 undergo the compound cyclic motion discussed earlier. This cyclic motion involves generally rotational motion of the pistons in one direction around the power cylinder l6 and simultaneously oscillatory motion of the pistons along the circular central axis of the cylinder. This cyclic motion occurs in such a way that adjacent pis tons move toward and away from one another to alternately expand and contract the working chambers 209 as they move with the pistons around the cylinder. Each revolution of each working chamber 20 around the power cylinder 16 constitutes one complete operating cycle of the chamber. In the course of each such cycle, each working chamber undergoes initial expansion through an inake phase, following contraction through a compression phase, following expansion through a power phase. and final contraction through an exhaust phase. As explained in more detail presently, each working chamber registers with the intake ports 24 during the intake phase, with the compression ports 26 near the end of its compression phase, with the power ports 28 during its expansion phase, and with the exhaust ports 30 during its exhaust phase.
The combustion chamber 12 is located on top of the power unit 15 and has a flat bottom face 72 in seating contact with a flat upper face 74 on the power unit. The combination chamber and power unit are rigidly joined by bolts 76 which extend through contacting flanges on the chamber and unit, as shown.
As shown in FIG. 2, the combustion chamber 12 has a generally triangular shape in transverse cross-section. Extending centrally through the chamber is a tube 78, the left end of which in FIG. 1 is open and terminates a short distance from the left end wall 80 of the combustion chamber. The compression passages 44 open to the interior space 81 of the combustion chamber about the outside of the tube 78 and are formed by ducts 82 which are integrally joined to opposite sides of the power unit housing 34 about the compression and power ports 26, 28. These ducts open inwardly toward the housing to communicate the compression passages to the compression ports and upwardly to the interior of the combustion chamber about its inner sleeve 78 to communicate the compression ports to the combustion chamber space 81. From this explanation, it is understood that the compression ports communicate through the ducts 82 and the combustion chamber space 81 to the open left end of the chamber sieeve 78.
Joined to the right end of the sleeve 78 in FIG. 1 is a power duct 84 which forms the power passages 45. This power duct is split into two separate duct portions 84a which extend lateraliy and downwardly through the compression ducts 82 to opposite sides of the power unit housing 34. then to the left in FIG. 1 through the latter ducts, and finally inwardly toward the housing. The power duct portions 84a open inwardly toward and are joined to the housing 34 about the power ports 28. The left end of the opening through the combustion chamber sleeve '78 thus communicates to the power ports through the power duct. It should be noted that the compression passage 44 comprises cssentiiilly an annular passage about the power duct 84.
The combustion means 14 of the combustion chani ber 12 comprises a fuel burner. This burner has a perforated sleeve 88 concentrically positioned in the open left end of the Combustion chamber tube '78 and a fuel inlet pipe 90 for supplying fuel to the burner sleeve. Fuel inlet pipe 90 is connected to a fuel supply (not shown) including a fuel pump for supplying fuel to the burner under pressure. A spark plug 92 is mounted in the burner tube 78 for starting the engine, as explained below. The walls of the combustion chamber 12 and power unit 15 have coolant passages 94 through which a liquid coolant may be circulated to cool the engine.
The operation of the continuous combustion engine It), as thus far described, is as follows. As each working chamber 20 undergoes its expanding intake phase past the intake ports 24, the chamber receives a charge of air through the intake ports. This air is then compressed during the following contrasting compression phase of the working chamber. Near the end of this compression phase. the working chamber registers with the compression ports 23 and the compressed air in the chamber is expelled through these ports into the com bastion chamber 12.
During its passage through the combustion chamber, the air mixes with the fuel entering the burner l4 and the resulting mixture is burned at substantially constant pressure to produce a hot pressurized combustion gas.
referred to herein as a working fluid. In this regard, it
will be understood that the engine is assumed to be in its operating mode with the pistons 18 rotating and combustion occurring at the burner 14. The engine is initially started by driving the pistons with a starting motor (notshown) coupled to the engine shaft 21 and firing the spark plug 92 from a voltage source (not shown). An obvious advantage of the invention which should be noted here is that the engine doesnot require a conventional spark ignition system operating continuly during and in timed retation to operation of the engine.
As noted earlier and shown in FIG. 1, the burner 1 4 has a perforated sleeve 88. Some of the compressed on entering the combustion chamber 12 from each work ing chamber 20 passes through the holes, referred to as dilution holes, to mix with the entering fuel and thereb reduce the fuel-air ratio and hence temperature to a le el the engine can withstand.
Proceeding now with the operation, after delivering its Compressed air charge to the combustion chamber 12, the working chamber 20 undergoes its expanding power phase past the power ports 28 and receives through these ports a charge of hot. high pressure working fluid from the combustion chamber. The pressure of this working fluid on the pistons l8 drives the latter in their cyclic motion around the power cylinder l6. thereby driving the shaft 31 in rotation and the working chamber through its power phase with resultant expansion of the working fluid. At the conciusion of this power phase, the working chamber enters its final contracting exhaust phase, during which the chamber reg; is ers with and the spent working fluid In the chamber is expelled through the exhaust ports 30. The cycle is then repeated. Each working chamber, of course. tin dergoes this same repetitive operating cycle.
Engine 10 is equipped with control means for controlling engine operation including a fuel control valve Ill (not shown) for regulating fuel flow to the burner 14. This valve has a pivoted arm 98 which is connected through linkage (not shown). to a throttle pedal or fuel control lever which is adjustable by the operator to adjust the fuel flow to the burner and thereby the engine power output. An additional speed responsive fuel metering valve (not shown) is required to regulate the fuel to the burner in response to engine speed to limit the air-fuel ratio at low speeds. Any suitable speed responsive valve mechanism which reduces the fuel flow at low engine speeds may be used for this purpose.
it can be demonstrated that the thermodynamic cycle which occurs in the engine is essentially a modified Brayton cycle involving adiabatic compression, heat addition at constant pressure. adiabatic expansion, and heat rejection at constant volume. In this regard refer once is made to H6. 6 which represents the pressurevolun'ie relationship of one working chamber 20 through one operating cycle. During this cycle, adiabatic compression initially occurs from a to b, where the working chamber initially registers with the com pression ports 26. From h to t, the chamber registers with and compressed air flow occurs from the chamber into the combustion chamber 12 through the compression ports. At point c. the working chamber is cut off from the compression ports, after which additional compression of the remaining air in the chamber occurs from c to d, which is top dead center of the cham' her. The working chamber then expands from d to e where the chamber registers with the power ports 28 and the previously compressed air which entered the combustion chamber from the working chamber and was heated within the combustion chamber re-enters th working chamber as hot, pressurized working fluid, causing the chamber pressure to rise to point f The working chamber continues to register with the power P9115 to point g where the chamber is blocked off from the ports after which the working fluid in the chamber undergoes adiabatic expansion from g to h At point It. the Working chamber registers with the exhaust ports and the working fluid exhausts to atmosphere while he working chamber contracts from h to 1'. At point i th chamber is blocked off from the exhaust port 30 and shortly thereafter registers with the intake port 24. The working chamber then expands from i to a while continuing to register with the intake port 24 and a fresh charge of air is drawn into the chamber. At point a the chamber is blocked off from the intake port and toe cycle then repeats. I The above discussion describes the four phase work- P.- ycle However, the engine can be mechanized while using the two phase working cycle by having the working chambers expand and contract only once durmg n h complete engine revolution and by having the working chamber register with both the intake and exst ports simultaneously while the chamber is at or near its maximum volume condition. The spent exhaust 15 er! forced out of the chamber by fresh incoming air whccn is provided by a scavenging means external to the engine.
in the present engine. the compression pressure in each working chamber 20 at the point at which the Chamber initially registers with the compression ports 26 exceeds the combustion chamber pressure. As a q ence. a throttling process occurs as the compressed air in the working chamber enters the combustion chamber. Assuming constant porting of the engine.
that is opening and closing of the engine ports 24, 26, 28, 30 occasioned by a fixed position of the reaction sun gear 46 relative to the power unit housing 34, this throttling process causes departure of the engine thermodynamic cycle from the cycle previously described under all operating conditions other than full power. In this regard, reference is made to FlG. which depicts the engine thermodynamic cycle under full load and partical load conditions with constant porting. The line H represents the throttling process which occurs at partial power.
According to a feature of the invention, the engine control means includes means 100 to vary the engine porting in response to adjustment of the fuel valve in such a way to minimize this throttling process. Means 100 comprises an irreversible hydraulic servomechanism 102 including a cylindrical hydraulic chamber 104 in the power unit housing 34. One side of this chamber is closed by a wall 106 of the housing between the chamber and the reaction sun gear 46. Coaxiaily fixed to the sun gear is a hub 108 which is rotatable on the engine shaft 21 and extends rotatably through a bore 109 in the wall 106 into the chamber 104. Hub 108 is sealed to the shaft and the wall of the bore by seals. not shown. Fixed to the hub within the chamber are circumferentially spaced vanes 110.
The outer side of the chamber 104 is closed by a circular plate 112 which is rotatable on the engine shaft 21. Plate 112 is positioned between the sun gear hub 108 and an annular shoulder 114 on the power unit housing 34 so as to be axially retained in position. The plate is sealed to the shoulder by a seal ring, not shown. Fixed to the inner side of the hydraulic chamber 194 are a set of circumferentially spaced vanes 116 defining intervening chambers 118 which receive the sun gear vanes 110. The vanes 110, 116 have close sliding tits in the chamber 104 to effectively seal the servo against hydraulic fluid leakage past the vanes.
Fixed to the servo plate 112 is an arm 120. The outer end of this arm is attached by a link 122 and arm 124 to the fuel valve adjustment arm 98 for angular adjust ment of the servo plate 112 in response to adjustment of the fuel valve.
Servo plate 112 has a group of three hydraulic fluid ports 126, 128, 130 opposite each sun gear vane 110. The center port 128 of each group is connected through a fluid line 132 to a source of hydraulic fluid under pressure. The two outer ports 126, 130 are con nected through hydraulic lines 134 to a low pressure hydraulic fluid receiver or reservoir from which the fluid is pumped to ports 128. Each vane 110 has two fluid passages 136, 138 which are spaced to register with the center servo plate port 128 and one or the other plate port 126, 130, as described below. Passages 136, 138 open through opposite sides of the vanes 110 into the vane chambers 118, as shown.
The above described ports and passages are arranged to have a neutral position (FIG. 3) in which all the ports 136, 128, 130 are blocked and the sun gear 46 remains stationary in a fixed position. Assume now the servo plate 112 is rotated in a direction to align its ports 126, 128 with their corresponding sun gear vane passages 136, 138. The vane chambers 118 are then pressurized at one side of the sun gear vanes 110 and vented at the other sides of these vanes in such a way as to cause the latter vanes to rotate in the direction of rotation f the servo plate to return the ports to their neutral position of FIG. 3. The same action occurs when the plate is rotated in the opposite direction. Thus the reaction sun gear 46 effectively follows the servo plate 112 so that the angle of the sun gear relative to the power unit housing 334 may be adjusted by adjusting the plate. The sun gear is thus angularly adjusted with adjustment of the fuel control valve 96 to regulate fuel flow to the engine burner 14.
According to the present invention, this sun gear adjustment is so arranged as to maintain approximate equality between the working chamber compression pressure and the combustion chamber pressure at initial communication of the working chambers 20 with the compression ports 26 under all load conditions and thereby reduce throttling of the compressed air entering the combustion chamber so as to preserve a more nearly perfect cycle as previously described under all load conditions. To this end, the sun gear adjustment is so arranged that as the fuel valve 96 is adjusted toward at reduced power setting, the sun gear 46 is rotated in a direction to effectively retard the cycle phases of the Working chambers 20 relative to the power unit ports 24, 26, 28, 30 and thereby effectively increase the working chamber volume at the point of initial communication of the working chambers with the compression ports 26.
FIG. 9 depicts the thermodynamic cycle of the engine which is achieved with this variable porting and FIG. 10 depicts the themodynamic cycle with fixed porting. Thus, FIG. 10 (a through f) shows how the indicator (pressure'volume) diagrams change with power setting or amount of fuel being introduced into the combustion chamber when the engine porting is not varied. Two different diagrams are shown for three dif' ferent power levels. The working chamber diagrams (FIGS. 10a, 10c and 10e) show how the chamber pressure increases until the compressor port 26 is uncovered at point 1, then drops to the combustion chamber pressure. The working chamber stays approximately constant until the power port 28 is cut off at point 5, then drops as the gas charge in the working chamber is expanded adiabatically. The above ignores the period from compressor port cut off at point 2 (FIG. 9) until power port uncover at point 4 (FIG. 9) during which the working chamber is isolated completely from the combustion chamber. During this period the working chamber reaches its minimum volume at point 3, so there is a pressure increase from point 2 to point 3 and then a pressure decrease from point 3 to point 4. However this has no significant effect upon the operation of the engine. Points 2 and 4 are not shown in FIG. 10 due to the fact they are not significant. Also ignored in FIG. 10 is the small pressure drop that will necessarily occur from the compressor port to the power port due to gas flow through the burner and ducting in the combustion chamber. The horizontal line attached to the bottom of the diagrams indicates the intake and exhaust phases for the four phase cycle mode of operation.
The combustion chamber diagrams (FIGS. 10b, 10d and 10]) show how the working fluid expands in the combustion chamber from compressor port uncover at point 1 until power port cut off at point 5. The expansion consists of a throttling process, denoted by H, followed by an expansion at constant pressure, denoted by Q. caused by the increase in temperature resulting from the combustion of fuel. The throttling pocess H is assumed to be a constant enthalpy process and for air is further assumed to be a constant temperature process. From the foregoing it is seen that the combustion chamber pressure depends upon the amount of fuel that is being admitted to the combustion chamber in relation to the air flow through the engine. As the amount of fuel is lowered more and more of the expansion is accomplished by the throttling process and less is accomplished by increase in temperature. The ther modynamic efficiency of the working cycle therefore becomes lower as the fuel flow is lowered and it can be shown that the efficiency is drastically lowered when the fuel flow is lower than approximately fifty per cent of the full power amount.
The above discussion assumes a steady state condition in which each charge admitted to the combustion chamber is expanded as described then transferred back to the working chamber. The actual situation is a quasi-steady flow condition and the combustion chamber volume is large enough to hold a number of individual charges. It will be understood by those versed in the art that although the discharge and intake flows at the compressor and power ports are intermittent in nature. the flow through the burner section is quasi-steady due to the compressibility and mass of the working fluid.
With the variable porting concept of FIG. 9, the compression ratio is effectively lowered so that the pressure that occurs in the working chamber just before the compression port is uncovered is just slightly higher than the pressure in the combustion chamber. As previously explained, as the reaction gear is rotated with respect to the engine case and ports, the working chamber reaches the compressor port uncover point earlier and with a larger volume so that the compression ratio is lowered. Also the working chamber reaches the power port cutoff point earlier and with a smaller volume so that the amount of volume expansion in the combustion chamber is smaller. To accomplish the above, the reaction gear is rotated a few degrees in the same direction that the output shaft is turning. The above action is shown on FIG. 9 since it is seen that point 1 moves to the right (to points 1' and 1") while point moves to the left (to points 5' and 5''). Another way to describe the action is to observe that the expansion from compressor port uncover, 1, to power port cutoff, 5, is adjusted to agree with the expansion resulting from the combustion of fuel, Q, therefore very little expansion due to throttling, H, can occur at any power setting of the engine. Also shown on FIG. 9 are points 2, 3 and 4 which show the pressure changes (not to scale) which occur in the working chamber while it is cut off from the combustion chamber. As mentioned above this has no significant effect upon the engine operation. Also shown is the horizontal line terminating at point 8 which represents the intake and exhaust phases if a four phase cycle is being utilized.
FIGS. 7 and 8 illustrate a modified continuous combustion engine 200 according to the invention. This engine, like that just described. has a power unit 202 and a combustion chamber 204. Power unit 202 comprises a number of power cylinders 206 containing reciprocating pistons 208 connected by connecting rods 209 to a crank shaft 210. Each piston and cylinder defines a working chamber 211.
Between the power unit 202 and combustion chamber 204 is a valve assembly 212. This valve assembly includes a valve block 213a located between and secured to the cylinder 206 and combustion chamber cover 213b and includes an intake port 214, a compression port 216, a power port 218, an exhaust port 220, and a cylinder port 222. The intake and exhaust ports 214, 220 open to atmosphere. The compression port 216 opens to the combustion chamber 204 about the outside of its duct 230 which contains the fuel burner 228 and tube 226. Tube 226 opens at one end to interior space of the combustion chamber about the duct. The opposite end of the tube is connected via a surrounding duct 230 and branch ducts 231 to the power ports 218.
Rotatable in the valve block 213a are a pair of valve sleeves 232, 234, with ports 236, 238, respectively, for each cylinder 206. Valve sleeves 232, 234 are connected via sprockets 240 and a timing chain 242 to the engine crank shaft for rotation in unison with the shaft. The valve sleeves 232, 234 are driven at one half the crank shaft speed.
The operation of the engine 200 will now be explained, assuming the engine is running and considering at first only the cylinder 206 shown in FIG. 8. The piston 208 is reciprocating causing alternate expansion and contraction of the working chamber 211. This working chamber has the same four phase expansioncontraction cycle as the working chambers in the earlier described engine. Thus during each cycle, the working chamber undergoes intake, compression, power, and exhaust phases. The valves 232, 234 are rotating in timed relation to these working chamber cycles.
As the working chamber 211 commences its intake phase, valve 232 rotates through an intake position wherein the valve ports 236 communicate the intake and cylinder ports 214, 222 so that a charge of air is drawn into the chamber. The valve ports are then blocked as the working chamber undergoes its compression phase to compress the air in the chamber. As the working chamber approaches the end of its compression phase, the valve ports 236 rotate to a compression position wherein they communicate the compression and cylinder ports 216, 222 and the compressed air is expelled from the working chamber into the combustion chamber 204. The air is heated at substantially constant pressure in the chamber, as before. The valve ports 236 are then again blocked. The ports 238 of valve 234 are blocked throughout the above portion of the cycle.
As the working chamber 211 commences its power phase, the ports 238 of valve 234 rotate to communicate the power and cylinder ports 218, 222. Hot, high pressure working fluid from the combustion chamber 204 then enters the working chamber 211 to drive the piston 208 through its power stroke with resulting expansion of the working fluid. At the completion of this power phase, the valve ports 238 rotate to communicate the exhaust and cylinder ports 220, 222 and the working chamber 211 undergoes its exhaust phase during which the spent working fluid is exhausted through the exhaust port 220 to complete one operating cycle. The valve ports 236 remain blocked through this last power and exhaust portion of the cycle and then rotate to communicate the intake and cylinder ports 214, 222 for the start of the next cycle.
As noted earlier, and shown in FIG. 7, the power unit 202 of engine 200 has a number of power cylinders 206 each containing a piston and defining a working chamber 211. Each of these working chambers undergoes 13 the operating cycle just described. The valve ports 236, 238 for the several power cylinders are angularly displaced in such a way that the several working chambers undergo their operating cycles in a pre-selected sequence.
it will be understood that the engine of FIGS. 7 and 8 is equipped with a fuel control valve, pressurized fuel supply, and speed responsive fuel metering valve like the engine of FIGS. 1-6. If desired. the engine of FIGS. 7, 8 may also be equipped with a variable valve porting means for angularly adjusting the valves 232, 234 with adjustment of the fuel control valve, independently of crank shaft rotation for the same reasons as in the earlier described engine of H08. 1-6.
The present engine has numerous features and advantages in addition to those already described. The continuous combustion process provides for complete combustion since relatively lean fuel-air mixtures are burned in the engine. The mixture ratio is comparable to that used in a gas turbine engine and the combustion process is also comparable to the gas turbine since the residence time of the fuel-air mixture is much greater than that of the conventional reciprocating engine. The present engine also shares with the gas turbine the ability to operate using a wide variety of fuels such as gasoline, kerosene, diesel fuel, various grades of fuel oil and, in fact, almost any fuel can be used including hydrogen.
Since the engine pistons are not subjected to the continuous flow of hot gas as mentioned earlier the only portion of the engine that is subjected to continuous high temperature is the duct that directs the gases to the power ports. However, this duct is not subjected to high stresses and the only pressure that it must withstand is the small pressure drop that results due to the gas flow through the duct and burner system inside the combustion chamber.
The present engine also shares with the gas turbine the ability to start easily in low ambient temperatures and to provide a low level of exhaust pollutants during the warm up period since there is no flame quenching on cold metal surfaces. Since the fuel-air mixture is lean more air must be moved through the engine to generate a given power level as compared to a conventional reciprocating engine. This means that more heat is rejected from the engine exhaust and consequently less conventional cooling capacity is required, that is less heat must be removed from the engine structure via liquid or air cooling passages. The present engine being a positive displacement engine has the advantage that the pressure supplied to the combustion chamber is practically independent of engine speed so that when the fuel flow to the engine is increased there is a minimum time lag until the torque output of the engine increases accordingly. The positive displacement feature also has the advantage that the engine has compressive braking capability comparable to the conventional reciprocating engine.
The rotary piston version of the invention has an additional advantage in that a greater air flow rate can be accommodated through the engine as compared to a conventional reciprocating engine given comparable overall engine bulk volume and weight. Also the rotary piston version allows the described continuous com- 6 bustion engine cycle and the described variable com pression ratio feature to be implemented easier since ports, not separate valves are used. The design of the duct in the combustion chamber is such that the hot working fluid does not contact the inner surface of the combustion chamber, but is contained by the duct itself.
1. A continuous combustion engine comprising:
a combustion chamber containing a fuel burner,
a housing, a rotary shaft supported in said housing, an annular power cylinder in said housing about said shaft. pistons in and movable around said cylinder and defining with the cylinder working chambers between the adjacent pistons, and means connecting said pistons, housing, and shaft for effecting re ciprocating motion of said pistons in timed relation during movement of said pistons around said cylin der in a manner such that said working chambers undergo alternate expansion and contraction during their movement around said cylinder with said pistons and that said shaft is rotated by movement of said pistons around said cylinder, and
valving means for effecting admission of air to each working chamber through an intake phase for com pression of said air and transfer of the compressed air to said combustion chamber through a port in said housing during contraction of the working chamber for heating through a transfer phase by fuel combustion of the air in said combustion chamber to produce a hot pressurized working fluid, transfer of said working fluid to the working chamber through a port in said housing during expansion thereof through a power phase to drive said pistons around said cylinder and thereby said shaft in rotation, and exhausting of the spent working fluid from the working chamber through an exhaust phase.
2. A continuous combustion engine according to claim 1 wherein:
said valving means comprise intake port means opening to said cylinder through which said air enters said cylinder during said intake phase, pressure port means communicating said cylinder and combustion chamber through which the compressed air passes from said cylinder to said combustion chamber during said transfer phase, power port means communicating said combustion chamber and cylinder through which said working fluid passes from said combustion chamber to said cylinder during said power phase, exhaust port means through which the spent working fluid is exhausted during said exhaust phase, and means on said pistons for opening and closing said port means in timed relation to movement of said pistons about said cylinder.
3. A continuous combustion engine according to claim 2 wherein:
each of said port means comprises a pair of parts opening through opposite sides of said power cylin der opposite one another to effect balancing of the lateral pneumatic forces on said pistons. 4. A continuous combustion engine according to claim 1 including:
means forregulating fuel flow to said burner, and means for adjusting the timing of said working cham ber phases independently of shaft rotation in uni son with adjustment of fuel flow to said burner. 5. A continuous combustion engine according to claim 1 including:
means for adjusting the timing of said working chamber phases independently of shaft rotation.
6. A continuous combustion engine according to claim 5 wherein:
said connecting means comprises planetary gearing including a sun gear fixed to said housing in concentric relation to said shaft, planetary pinions associated with said pistons, respectively, and meshing with said gear, a spider fixed to said shaft and rotatably mounting said pinions, whereby said pinions undergo rotation on their central axes during rotation of said shaft, spider, and pinions relative to said gear, and means connecting each pinion to its associated piston in a manner such that rotation of each pinion about its central axis imparts a reciprocating motion to its associated piston, and
said timing adjustment means comprises means for rotatably adjusting said sun gear about the axis of said shaft 7. A continuous combustion engine according to claim 6 wherein:
said sun gear adjusting means comprises a servo plate rotatable on said shaft, interfittig radial vanes on said sun gear and said housing defining pressure chambers between the adjacent gear and housing vanes, means for pressurizing said chambers in a manner which tends to maintain the sun gear vanes positioned between the housing vanes in accordance with the servo plate position, and means for rotatably adjusting said servo plate relative to said shaft.
8. A continuous combustion engine according to claim 1 wherein:
said combustion chamber has an outer wall, an inner combustion sleeve within and spaced from the outer chamber wall and containing said burner, and means communicating the ends of said sleeve to said ports, respectively, whereby compressed air flow occurs from said working chambers to said sleeve to produce said working fluid and said working fluid flows from said sleeve back to said working chambers.
9. A continuous combustion engine according to claim 8 wherein:
compressed air flow from said working chambers to said sleeve occurs over the exterior of said sleeve.