US3042010A - Fuel injector - Google Patents

Description

FUEL INJECTOR 2 Sheets-Sheet 1 Original Filed May 16, 1958 INVENTORS ROLLIN J. M CRORY ROBERT W. KING O O O ROBERT M. CONKLIN 3,042,010 FUEL INJECTQR Rollin J. McCrory, Worthington, and Robert W. King and Robert M. Conldin, Columbus, Ohio, assignors, by mesne assignments, to The Battelie Development Corporation, Columbus, Ohio, a corporation of Delaware Original application May 16, 195%, Ser. No. 735,795, new Patent No. 2,959,159, dated Nov. S, 1960. Divided and this application Mar. 16, 196i), Ser. No. 15,302

19 Ciaims. (Cl. l23--32) This invention relates to improvements in the fuel supply system for the free-piston engine, and, more particularly, to a fuel injection system especially adaptable to a free-piston engine. This is a divisional application of our copending application entitled Free-Piston Internal Combustion Apparatus, Serial No. 735,795, filed May 16, 1958, now Patent 2,959,159, issued November 8, 1960. Free-piston engines are those in which the reciprocating action of the piston, or pistons, is not mechanically restrained by the conventional connecting rod and crankshaft. Although most of the multipiston freepiston engines have mechanical connections between the pistons to maintain the proper phasing between the pistons, the end positions of the piston stroke are not established by the mechanical connections. The end positions of the piston stroke are established on each engine cycle by the energy released to the work article, or load, that is being driven by the engine, the energies of the combustion process, and the resilient rebound system.

Briefly described, the present invention includes means for pressurizing fuel in a fuel-injector device, means for retaining the fuel under pressure, reciprocal means to open communication means between the fuel injector and the combustion cylinder of the engine allowing the pressurized fuel to be injected into the combustion cylinder. The reciprocating action of the injector is especially suited to an engine with no rotating parts and provides excellent timing of fuel injection with the combustion stroke of the engine.

One embodiment of this invention comprises a body member having a discharge outlet into the combustion cylinder of the engine and having a plurality of recesses. A plunger reciprocates in one of the recesses of the body member with resilient means to move the plunger in one direction and actuator means to move the plunger in the opposite direction. A diaphragm is disposed in another one of the recesses of the body member partitioning the recess into a first and second chamber. Resilient means in the first chamber urges the diaphragm toward the second chamber. Fuel is supplied under pressure to the second chamber and to the plunger recess. The plunger recess communicates with the first chamber and the fuel discharge outlet. A conduit in the plunger alternately registers with the fuel supply and the communication with the first chamber. The pressure in the first chamber is alternated between the fuel pressure and the pressure of the combustion cylinder which flexes the diaphragm and injects fuel into the combustion cylinder of the engine.

Another embodiment of the invention comprises a body member having a dischange outlet into the combustion cylinder of the engine, a plurality of chambers, and a plunger reciprocal in a bore in the body member; resilient means disposed in the body member urging the plunger in movement in one direction and actuator means engaging the plunger and operable to move the plunger in the opposite direction; means for supplying fuel and means for supplying air to the plunger bore at superatmospheric pressure; communication means between a first one of the chambers and the plunger bore, combore at a third position, the second conduit sequentially registering between the first chamber communication means and the air supply means at a first position, with the plunger bore at a second position, between the first chamber communication means and the second chamber communication means at a third position with the second chamber communication means being open to atmos-.

phere at the first position.

A feature of the present invention is a fuel injection system controlled by the reciprocation of the engine system providing proper timing for fuel injection.

Another feature of this invention is a fuel injection system that receives the power for its operation in the form of direct mechanical and hydraulic energy from the englue.

Still another feature of the present invention is a fuelinjection system capable of positively injecting a fuel charge into the combustion chamber under the control of means operated directly and properly timed in con neotion with the rapid reciprocation of the free piston.

Other features and objects of the invention will be apparent from the attached drawings, and the following description. This invention comprises apparatus and a method of applying the same, the preferred form of which is disclosed in the following description and attached drawings. Although the appanatus, structure, and method described and shown in detail refer with particularity to a fuel injection system for a single-cylinder, free-piston engine, it is apparent that this invention should not be limited thereto. The invention may be used for other purposes, where its features are advantageous.

In the drawings:

H6. 1 is an elevational, partially sectioned view of a free-piston engine showing the fuel-injection system in connection therewith;

FIG. 2 is an elevational, partially sectioned view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional, elevational view of a diaphragm operated fuel injector according to this invention;

FIG. 4 is a schematic elevational view of a fuel tank to be used with this invention;

FIG. 5 is a sectional, elevational view of an air-blast fuel injector according to this invention;

FIG. 6 is a partial sectional view of the air-blast fuel injector of FIG. 5 with the plunger at a different position; and

FIG. 7 is a sectional, elevational view of another embodiment of an air-blast fuel injector according tothis invention.

Referring to FIGS. 1 and 2, a free-piston engine 50 comprises a block or frame 51 and a free piston 52 reciprocal therein. The frame 51 is provided with an internally bored combustion cylinder 53 and provided in communication therewith is a coaxial greater-diameter compression cylinder 54. Closing the compression cylin- 3 and the combustion cylinder 53 by means of the exhaust ports 57.

An annular intake manifold 63 is also provided in the frame 51 at a position further removed from the head end of the combustion cylinder. Communication is established between the combustion cylinder 53 and the intake manifold 63 by intake ports 58.

At the head end 64 the combustion cylinder 53 is provided with ignition means 65, such as a spark plug. Centrally positioned on the axis of the combustion cylinder 53, at the head end 64, is the fuel nozzle 66 of a fuel injector, designated generally as 68.

An exhaust outlet 87 is provided at one position in the exhaust manifold 62.

As shown in FIGS. 1 and 2, piston 52 is constructed with a minor-diameter portion 88 that is adapted to reciprocate in the combustion cylinder 53, being sealed with the cylinder wall 61 by means of piston rings 89. At the opposite end piston 52 is formed in a greater-diameter portion 90 which is adapted to reciprocate in a compression cylinder 54 and is sealed in connection therewith by means of the piston ring 91. The minor-diameter portion 88 is provided with a longitudinal cam groove 93.

. The free-piston engine 50 shown in FIGS. 1 and 2 is provided with a piston rod 94 fastened to or formed integrally-with piston 52 and adapted to protrude through the base plate 55 and reciprocate therein through a bushing 95 with a seal 102. The piston rod 94, shown in FIG. 1, is constructed with a threaded end 96 to receive and hold a reciprocating tool. I

Compression cylinder 54 is divided by the major-diameter portion or piston flange 90 into a bounce chamher 111 on the one side (lower side in FIG. 1) and a counterchamber 112 on the other side (upper side in FIG. 1). Since, in FIG. 1, the piston 52 is shown at its uppermost head-end position, bounce chamber 111 is at its maximum volume, while counterchamber 112 is at minimum volume. On the other hand, in FIG. 2 the piston is shown at the bottom of its stroke and bounce chamber 111 is of minimum volume and counterchamber 112 is of maximum volume. Near each end of the compression cylinder 54, pressure- relief valves 113 and 114 are provided in the frame 51. Relief valve 113 is in communication with counterchamber 112 by means of a conduit 115. Relief valve 114 is in communication with bounce chamber 111 by means of a conduit 1 16.

At a position circumferentially removed from the relief valves 114 and 115 is located an inlet air valve chamber 117 and a scavenge air valve chamber 118. Each of chambers 117 and 118 is formed from a recess in the frame 51 and a cover plate 119 and 120, respectively. Cover plates 119 and 120* are held in place by suitable means, such as screws 121.

The inlet air valve chamber 117 is provided vw'th a reed-type inlet air valve 122 adapted to open and close with respect to an inlet air valve port 123. Communication is provided between counterchamber 112 and valve chamber 117 by means of an inlet port 124.

On the opposite side a scavenge valve 125, of the reed type, is adapted to open and close a scavenge air port 126 in communication with counterchamber 112. A conduit 127 is provided in the frame 51 connecting the intake manifold 63 with scavenge air valve chamber 118.

Bounce chamber 111 is connected to an accumulator 291 (FIG. 4) by means of an accumulator line 128. This connection may be made at the frame 51 by means of a suitable fitting 129 on a check valve 130 which is threadedly received in the side of the frame 51.

At one side of the engine 50, a cam-follower actuator rod 139, having a suitable seal 137, is positioned in camfollower bore 59 forradial reciprocation when actuated by a cam follower 140 operating in cam-follower groove 93.

As the piston 52 reciprocates longitudinally, cam follower 140 is caused to reciprocate radially with respect to the pistons 52 by the depth and contour of cam groove 93. Actuator rod 139 engages an end 141 of a rocker arm 142. At the opposite end, rocker arm 142 is in contact with a plunger or stem 143 of the fuel injector 68. A trunnion yoke 144 pivotally supports rocker arm 142. Resilient means, such as a spring 145, acting against a collar 146 urges actuator rod 139 into continuous contact with the cam groove 93.

In the description of the engine 50 and the description of its operation to follow, reference may be made to the power stroke as the down stroke and the compression stroke as the up stroke. This is in conformity with the position of the engine in' FIGS. 1 and 2. This terminology is employed for descriptive convenience and defines no limitation of the position of the engine, as the engine may be operated at any orientation.

Operation In the combustion cycle of free-piston engine 50, up- Ward movement of the piston compresses air which has been admitted from the intake manifold 63 through the intake ports 58. Fuel is admitted through the fuel nozzle 66, forming a combustible mixture which is ignited by spark plug 65 at or near the time the piston reaches headend position shown in FIG. 1. Ignition and burning of the fuel forces the piston 52 downward, making energy available at the connection 96 of piston rod 94. When the piston 52 passes exhaust ports 57 on the downward stroke, products of combustion are exhausted through these ports into exhaust manifold 62. Continued downward progress of piston 52 opens intake ports 58, permitting the admission of air to scavenge the combustion cylinder 53.

During the downward stroke of the piston 52, air is compressed in bounce chamber 111, storing energy to return the piston 52 for the next upward stroke. At the same time, inlet air valve 122 opens by reason of the less-than-atmospheric pressure created in counterchamber 112 by the downward stroke of piston 52. Opening of inlet valve 123 admits air to the counterchamber 1 12.

On the down stroke of piston 52, when the pressure in bounce chamber 111 exceeds the pressure in accumulafor 2 91 and line 128 by an amount sufiicient to open check valve 131 air is pumped into the accumulator for operation of the fuel injector 63.

The compression energy of the air in bounce chamber 111 forces the piston 52 up on the compression stroke. The air in counterchamber 112 is compresesd causing scavenge air valve 125 to open and the air to be expelled through the scavenge air port 126. Compressed air is forced from scavenge air chamber 118 upward through conduit 127 into intake air manifold 63 for operation of the combustion cycle of the engine. After the majordiameter portion of piston 52 closes inlet port 124 and scavenge air port 126 on the upstroke, air is compressed in counterchamber 112, serving to help decelerate the piston to a stop at the head-end position.

Pressure-relief valve 113 provides for a predetermined maximum pressure in counterchamber 112, and therefore, a fixed maximum energy return to the system on the combustion stroke. Conduit of pressure-relief valve 113 is located a short distance from the upper end of counterchamber 112, and the remaining short distance provides a completely sealed air cushion for safety purposes. This air cushion prevents the piston from making contact with the ends of counterchamber 112 or combustion cylinder 53. Pressure-relief valve 114, near the lower end of the bounce chamber 111, is provided for a purpose similar to that of relief valve 113 on counterchamber 1 12.

Fuel injector 68 has been provided in combination with engine 50 to assure fuel admission which is precisely timed and which is directly initiated and sustained by the engine 50, as shown in FIG. 3.

As has been previously explained the continuous re-' liable operation of a free-piston engine under varying load condition requires precise control of combustion conditions. Proper timing, and fuel pressures, at the time of fuel injection are important factors in this combustion control so that the proper fuel quantity and dispersement are obtained.

Fuel injector 63 comprises a body portion 250 and a closure portion 251 assembled with a gasket 252 impressed there between and held in place by suitable means such as screws 253 positioned in counterbores 254. Body portion 250 is provided with a threaded insert portion 67 which is engaged in the head end 64 of combustion cylinder 53. Insert 67 is constructed with an end surface 255 having a fuel nozzle 66 opening therein.

Body portion 255 of fuel injector 68 is provided with a laterally disposed bore 256 which terminates at one end in a wall with an aperture 257. At the opposite end bore 256 is counterbored and threaded, and receives an adjustable retainer screw 258. A plunger 259 is disposed within the bore 256 and is constructed to reciprocate therein in one direction when actuated by pressure of rocker arm 142 upon plunger stem 143. Operation of the plunger 259 in the opposite direction takes place under the urging of resilient means, such as compression spring 261 that engages plunger 259 at one end and retainer screw 258 at the opposite end.

An injector chamber 262 in the form of a counterbore having an upstanding passage-enclosing pedestal 263 is provided in the upper surface of the body portion 250. An injection conduit 264 connects bore 256 with fuel nozzle 66. At the opposite side, a chamber inlet passage 283 connects bore 256 with chamber 262.

Cover portion 251 is provided with a pressure chamber 265 in the form of a counterbore that is constructed to register with injection chamber 262. Recesses 266 are provided at the edges of chambers 262 and 265 to receive in assembly a diaphragm unit 267.

Diaphragm unit 267 comprises a centrally positioned flexible diaphragm member 268 having fastened thereto at each side annular washers 269 and centrally positioned pressure plates 270.

A diaphragm stop screw 271 is threadedly engaged in cover portion 251 in position to contract upper pressure plate 270 of diaphragm unit 267. The position of contract is adjustable by means of rotation of the diaphragm stop 271 and a particular setting may be held by means of a lock nut 272. Resilient means such as an injection chamber spring 273 is positioned in the injection chamber 262 over pedestal 263. Spring 273 engages lower pressure plate 270 at one end and the base of the injection chamber 262 at the opposite end.

An inlet conduit 274 communicates with a fuel line 275 through a conventional tube connection 276. Inlet conduit 274 communicates with pressure chamber 265 in one branch 277 and with plunger bypass conduit 278 in the other branch. Plunger bypass conduit 27 8 terminates in port 280 at the lower side of bore 256-. A passage 281 provides communication between a position opposite port 280 and chamber inlet passage 283.

Plunger 259 is provided with an annular groove 282 in the outer surface thereof which is positioned to provide communication between port 280 and passage 281 when plunger 259 is in the extreme right hand position, as shown in FIG. 3.

In the operation of the fuel injector 68, fuel is supplied under pressure through fuel line 275. Fuel line 275 is connected to a fuel tank, designated generally as 290, and diagrammatically shown in FIG. 4. Fuel tank 290 comprises an upper accumulator portion 291 and a lower storage portion 292, which are hermetically sealed by a diaphragm 293. Accumulator section 291 is provided with a hand pump 294 and is connected to accumulator line 128 from chamber 111 of engine 51). Storage portion 291 is provided with a fill spout 295 that is equipped with a scalable cap 296.

In the normal operation of the engine, air in the accumulator portion 291 is maintained at an elevated pressure by reason of the communication established with bounce chamber 111 through line 123 and check valve 130. The elevated pressure in chamber 291 deflects diaphragm 293 downward putting the fuel under pressure. Pressurized fuel is transferred from tank 290 to fuel injector 68 through fuel line 275.

Fuel enters the fuel injector 68 through inlet conduit 294, passing to pressure chamber 265 through passage 277 and to injection chamber 262 through bypass conduit 278, groove 282, passage 281, and the upper portion of injection conduit 266. With the pressure equal on both sides of the diaphragm, i.e., at the same fuel injection pressure, the force of spring 273 keeps diaphragm unit 267 in its upper portion against diaphragm stop 281.

On the up stroke of piston 52, cam follower follows the bottom of cam groove 93 forcing actuator rod 139 radially outward in bore 59 against the urging of spring 145. Outward movement of actuator rod 139 operates rocker arm 142 to force plunger stem 143 to the left, as shown in FIG. 3. Plunger 259 is moved to the left by plunger stem 143 until groove 282 aligns with injection conduit 264. The movement of groove 282 away from port 280 operates as a valve closure in inlet fuel conduit 274 at port 280; and injection chamber 262 is therefore sealed off from inlet fuel and inlet fuel pressure. With injection conduit 264 open from injection chamber 262 to nozzle 66 and with fuel in the pressure chamber 265 at a higher pressure than the pressure in the combustion cylinder, the force of spring 273- is overcome and diaphragm unit 262 moves downward forcing fuel from nozzle 66 into the combustion chamber.

The amount of fuel which is injected by the operation of the diaphragm depends upon the displacement or stroke of the diaphragm, and this is controlled by means of adjustment in the position of diaphragm stop 271.

When piston 52 returns on the downstroke actuator rod spring 145 and plunger spring 261 return the plunger 259, rocker arm 142, and actuator rod 139 to the starting position.

In normal operation, the injection cycle is repeated once for each operating cycle of the engine, continuously, and directly timed by the actuation of piston 52.

In order to start the engine it is necessary that the fuel be pressurized for the first injection. When operation commences pressure in chamber 111 will normally be atmospheric, and therefore, means such as a hand pump: 294 is provided to pressurize the fuel injection system before the engine is started. When starting, it also may be necessary to operate plunger 259 once manually by means of manipulation of rocker arm 142 to assure that the injection chamber 262 is completely filled with fuel under pressure.

The diaphragm operated fuel injector 68 of this invention is actuated directly by piston '52 and utilizes reciprocal motion for its operation. In the free-piston engine 50, the motion delivered is reciprocating, and therefore, the fuel injector 68 combines with the free-piston engine 50 to provide continuous reliable operation and a clearly controlled combustion cycle.

In addition, the compactness of the fuel injector 68 is an advantage in that it increases the portability of the engine with which it is combined.

Another form of a fuel injector that may be combined with the free-piston engine 5t of this invention is designated generally as 350 and shown in FIGS. 5 and 6. In general, fuel injector 350 comprises a body 351, a cover 352, a plunger 353, and resilient means 354, such as acompression spring.

Body 351 is constructed with a fuel-blast chamber 355, a pressure equalizer chamber 356, and a plunger chamber or bore 357. The blast chamber 355 is provided:

with a first conduit 358 for communication between the chamber 355 and the bore 357. Blast chamber 355 is also provided with an equalizer conduit 359 at a position removed from conduit 358. The equalizer conduit 359 provides communication between chamber 355' and bore 357. Chamber 356 is provided with a passage 360 between the chamber 356 and an annular groove 36-1 in the wall of bore 357. Both chambers 355 and 356 are closed by cover 352 which is held in place by suitable means, such as screws 362. A gasket 363 may be provided to assure that the chambers 355 and 356 are sealed from each other and from the atmosphere.

The plunger 353 is constructed to reciprocate between the extreme left-hand position shown in FIG. and the extreme right-hand position shown in FIG. 6. At one end, plunger 353 is provided with a stem 364 in operative contact with rocker arm 142 of engine 56. At the opposite end spring 354 is disposed between the end of plunger 353 and the end of bore 357. An aperture 365 is provided in the end of bore 357 establishing communication between the atmosphere and the end of plunger 353. Intermediate the ends of the body portion of plunger 353 are provided a plurality of spaced passages 366 and 367.

Communication is provided between a fuel nozzle and bore 357 by a fuel injection conduit 370.

A fuel inlet conduit 371 is provided from a fuel supply tube 372, through connection fitting 373, to a recess 374 at the bottom side of bore 357. Fuel inlet conduit 371 is constructed to bypass blast chamber 355 and is sealed therefrom. An air inlet conduit 375 is provided in body portion 351 and cover 352 connected to air supply tube 376 by means of fitting 377. Air supply conduit 375 connects with bore 357 through a recess 378 in the side there of and is constructed to bypass blast chamber 355, sealed therefrom.

In the free-piston engine 50 and fuel injector 350 combination, air supply tube 376 is connected to an accumulator such as chamber 291 by a conventional tubing connection 377, and fuel supply tube 372 is connected to a fuel tank 290, such as the tank shown in FIG. 4.

In operation of the fuel injector 350, spring 354 forces stem 364 and plunger 353 to the extreme right-hand position, shown in FIG. 6, on the down stroke of the engine.

When piston 52 comes up on the compression stroke rocker arm 142 forces plunger 353 to the extreme lefthand position, shown in FIG. 5, through actuator rod 139 and cam follower 140 in cam groove 93.

When plunger 353 reaches the right-hand position,

pressurized fuel in inlet conduit 371, and recess 374 moves into fuel passage 366. Simultaneously, pressurized air in air inlet conduit 375 and recess 378, passes through passage 367 and conduit 358, and enters blast chamber 355. The air in blast chamber 355 is brought to a first pressure P equal to that of the air in inlet tube 376. Equalizer chamber 356 is in communication with the atmosphere through conduit 360, groove 361, bore 357, and aperture 365.

7 As piston 52 moves upward on the compression stroke, plunger 353 moves to the left bringing passage 366 momentarily into a position of registry with conduit 358 and fuel injection conduit 370. At this momentary position, air in chamber 355 at pressure P forces the fuel carried in passage 366 downward through fuel injection passage 370 and out through the nozzle by blast effect. This blast eifect lowers the pressure in the blast chamber 355.

Continued travel to the left brings plunger 353 to the position shown in FIG. 5. In this position, passage 367 is aligned with conduit 359 and groove 361. This brings blast chamber 355 into communication with equalizer chamber 356, allowing pressure to decrease in chamber 355 and to increase in chamber 356 until they are equal. The volumes of chambers 355 and 356 are predetermined to be that which, in conjunction with the inlet air pressure and blast effect, will establish a pressure P in chamber 355 substantially equal to combustion cylinder 53 pressure at the time fuel passage 366 registers with conduit 358 and conduit 370 on the down or power stroke.

When the piston reverses and starts down, plunger 353 is urged and moves to the right by spring 354. At the time fuel passage 366 momentarily registers with conduit 358 and conduit 370, there is no air flow through passage 366 because of equal pressure conditions at both ends. This prevents the very bad problem of second injection which would occur if the pressure in chamber 355 were higher than the pressure in the combustion cylinder 53 on the down stroke of piston 52. When plunger 353 reaches its extreme righthand position again, as shown in FIG. 6, the injection cycle is complete and ready for the next compression stroke. The injection cycle abovedescribed continues repeatedly once for each cycle of engine 50.

Fuel injector 350 combines with engine 50 to provide a free-piston engine in which fuel injection is positive and precisely timed without auxiliary equipment, such as an air compressor or rotary timing cam shafts. The fuel injector 350 is operated directly from the reciprocating motion of the engine 50 and therefore utilizes the reciprocating motion of piston 52 without transformation to rotary action. A rotary motion mechanism for driving auxiliaries would increase the size, cost, weight, and friction on engine 50.

Since fuel injector 350, utilizes the reciprocal motion of the engine 50, the engine is more compact and is quieter. Compactness reduces weight and increases the portability of the engine, as well as increasing the horsepower per pound of engine weight. In addition, the useful power of the engine is increased as there is less loss in friction and power for the fuel injection auxiliary.

Another form of fuel injector, that is operable directly through the reciprocating motion of piston 52 in a freepiston engine 50, is shown in FIG. 7. Fuel injector 380 in general comprises a body portion 381, a cover 382, a plunger 384, a needle valve 385, and an orifice tube 386. Body portion 381 and cover 382 are formed to be joined into a single unit at mating surfaces 387. A chamber 388 is formed by the body 381 and cover 382 each being provided with a semicylindrical cavity therein. A gasket 389 is disposed between the surfaces 387, and is adapted to be compressed when cover 382 is fastened tight by suitable means, such as screws 390.

Body 381 is provided with a lateral plunger bore 391 which connects at one end with a counterbore 392 of larger diameter. A compressed air supply tube 393 is connected to an air inlet conduit 394 by means of a suitable fitting 395. Air conduit 394 intersects bore 391 at one side in an aperture 396. At the opposite side of bore 391, a chamber inlet conduit 397 provides communication between bore 391 and chamber 388. At a position removed from the entrance of chamber conduit 397, an outlet passage 398 provides communication between chamber 388 and bore 391. Outlet passage 398 continues from a position at the opposite side of bore 391 to a fuel nozzle 399.

A fuel inlet tube 480 is connected to a fuel inlet conduit 401 by means of a suitable fitting 482. Fuel inlet conduit bypasses chamber 388 and is constructed to communicate with the central bore of orifice tube 386 at one end 403.

Needle valve 385 is threadedly engaged in body portion 381 in axial alignment with orifice tube 386 with the point of the needle 385 in the orifice end of tube 386.

Plunger 384 is provide with a plurality of annular grooved portions 404 and 405 which are spaced from one another a distance greater than the distance between inlet conduit 397 and the outlet conduit 398. At one end, plunger 384 is provided with a stem portion 406 of lesser diameter which is adapted to receive a collar 407 retained in position against a shoulder 488 by suitable means such as a cotter pin 409. Resilient means, such as a spring 410, is disposed between the bottom of counterbore 392 and collar 407. A cap 411 is positioned on the stem 406 and retained in position by rocker arm 142.

The fuel injector 380 is connected to frame 55 of engine 50 by means of a threaded insert portion 412.

As in the previous form of fuel injector 350, compressed air inlet tube 393 is connected to an accumulator, such as chamber 291, of fuel tank 290, shown in FIG. 4. Fuel inlet tube 4% is connected to the fuel tank 299'.

Rocker arm 142 is actuated to the left (in FIG. 7) on the up stroke and to the right on the down stroke of piston 52.

In FIG. 7, plunger 384 is shown at its extreme right hand position of travel which is the position corresponding with the maximum downward travel of piston 52 in engine 59. Groove 4G4 aligns with conduits 396 and 397 and air is forced by pressure across the end of orifice tube 386. A quantity of fuel from fuel inlet conduit 401 is carried into chamber 388. The amount of fuel carried may be adjusted by means of the threaded adjustment of needle valve 385. The fuel and air mixture swirls in chamber 388 at a pressure P substantially equivalent to that of the inlet compressed air.

On the upward stroke of piston 52, rocker arm 142 forces plunger 384 to the left bringing groove 405 into alignment with outlet 398 and moving groove 404 out of alignment with conduits 396 and 397. When piston 52 arrives at its position of maximum upward travel, groove 405 is properly registered and the fuel in chamber 388 is injected into combustion chamber 53 through fuel nozzle 399 by reason of the higher pressure P in cha'mber 388 than that in combustion cylinder 53.

The movement of plunger 334 to the left compresses spring 410. This compression of spring 410 returns plunger 384 to the position shown, as rocker arm 142 moves to the right on the down stroke of piston 52.

In another method of operation of fuel injector 380, the position of groove 405 is established with respect to the travel of plunger 384 so that on the up stroke of piston 52 groove 405 passes to the left beyond registry with conduit 398. This provides for an earlier fuel injection on the up stroke of piston 52. In this method of operation, the size of chamber 388 is determined in conjunction with the fuel injection pressure and the cylinder compression pressure so that on the return movement of plunger 384 the pressure in chamber 388 and combustion cylinder 53 will be substantially equal. Therefore, no second injection will occur when groove 405 passes registry with conduit 398.

When piston 52 reaches its lower position, plunger 384 returns to its extreme right-hand position, shown in FIG. 7, and the injection cycle is complete for one cycle of engine 50. The injection cycle repeats consecutively once for each complete cycle of engine 50 and under direct and precise timing control from the operation of piston 52 and engine 59. Fuel injector 38%) combines with engine 50 utilizing the reciprocating motion generated by the engine directly and a rotary motion mechanism is not required. A rotary motion mechanism for driving auxiliaries would increase cost, weight, size, and friction.

Since fuel injector 380 utilizes the reciprocating motion of the engine 50, the engine is more compact and is quieter. Compactness reduces weight and increases the portability of the engine, as well as increasing the horsepower per pound of engine weight. In addition, the useful power of the engine is increased as there is less loss in friction and power for the fuel injection auxiliary.

It will be understood of course, that while the forms of the invention herein shown and described, constitute preferred embodiments, it is not intended to illustrate all possible forms or ramifications of the invention. It will also be understood that the words used are Words of description rather than words of limitation and that various changes, such as changes in shape, size and arrangement of parts may be made without departing from the spirit and scope of the invention herein disclosed.

What is claimed is:

1. In a free-piston engine having a cylinder, piston, and compressors, a fuel injection system, comprising: a body member having a cavity for retaining pressurized fuel and having a discharge outlet in said cylinder; a fuel container having a first chamber and a second cham ber; a flexible partition between said first chamber and said second chamber containing fuel communication means between said compressor and said first chamber whereby gas supplied from said compressor flexes said partition to pressurize said fuel; communication means between said second chamber and said cavity for supplying pressurized fuel to said cavity; a reciprocal plunger, having a conduit therein, disposed between said cavity and said discharge outlet to provide intermittent communication between said cavity and said discharge outlet; and actuator means engaging said plunger and operable to reciprocate said plunger.

2. In a free-piston engine having a cylinder, piston, and compressor, a fuel injection system, comprising: a body member having a cavity for retaining pressurized fuel and having a discharge outlet in said cylinder; a fuel container having a first chamber and a second chamber; a flexible partition between said first chamber and said second chamber containing fuel communication means between said compressor and said first chamber whereby gas supplied from said compressor flexes said partition to pressurize said fuel; communication means between said second chamber and said cavity for supplying pressurized fuel to said cavity; a reciprocal plunger, having a conduit therein, disposed between said cavity and said discharge outlet to provide intermittent communication between said cavity and said discharge outlet; a longitudinal cam groove provided on said piston; a cam follower in contact with said cam groove; and a rocker arm engaging said cam follower and said plunger whereby, on reciprocation of said piston, said cam groove, cam follower and rocker arm cooperate to provide reciprocating motion to said plunger.

3. A fuel injector for internal-combustion engines having a combustion cylinder comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of recesses; a plunger reciprocable in one of the recesses in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; actuator means engaging said plunger member and operable to move said plunger in the opposite direction; a diaphragm partitioning another of said recesses into a first and a second chamber; resilient means in said first chamber urging said diaphragm toward said second chamber; means for supplying fuel at a first pressure to said second chamber and to said plunger recess; communication means between said first chamber and said plunger recess, and between said plunger recess and said fuel discharge outlet; and conduit means in said plunger, said conduit means in reciprocation of said plunger alternately registering with said supply means and communication means, and alternating the pressure in said first chamber between said first pressure and the pressure of said combustion cylinmember having a discharge outlet in said combustion cylinder and being formed with a plurality of recesses; a plunger reciprocable in one of the recesses in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; a

longitudinal cam groove provided on said piston; a cam follower in contact with said cam groove; a rocker arm engaging said cam follower and said plunger whereby on reciprocation of said piston, said cam groove, cam follower, and rocker arm cooperate to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; diaphragm partitioning another of said recesses into a first and a second chamber; resilient means in said first chamber urging said diaphragm toward said second chamber; means for supplying fuel at a first pressure to said second chamber and to said plunger recess; communication means between said first chamber and said plunger recess, and between said plunger recess and said fuel discharge outlet; and conduit means in said plunger, said conduit means in reciprocation of said plunger alternately registering with said supply means and communication means, and alternating the pressure in said first chamber between said first pressure and the pressure of said combustion cylinder; said alternating pressure flexing said diaphragm to inject fuel into said combustion cylinder.

6. In a free-piston-engine compressor having a cylinder and piston, a fuel-injection system comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of recesses; a plunger reciprocable in one of the recesses in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; a longitudinal cam groove provided on said piston; a cam follower in contact with said cam groove; a rocker arm engaging said cam follower and said plunger whereby on reciprocation of said piston, said cam groove, cam follower, and rocker arm cooperate to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; a diaphragm partitioning another of said recesses into a first and a second chamber; resilient means in said first chamber unging said diaphragm toward said second chamber; a fuel container having a gas chamber and a fuel chamber; a flexible partition between said gas and fuel chambers; communication means between said compressor and said gas chamber whereby gas supplied from said compressor flexes said partition to pressurize fuel in said fuel chamber; communication means between said fuel chamber and said second chamber for supplying fuel at a first pressure to said second chamber and to said plunger recess; communication means between said first chamber and said plunger recess, and between said plunger recess and said fuel discharge outlet; and conduit means in said plunger, said conduit means in reciprocation of said plunger alternately registering with said supply means and communication means, and alternating the pressure in said first chamber between said first pressure and the pressure of said combustion cylinder; said alternating pressure flexing said diaphragm to inject fuel into said combustion cylinder.

7. A fuel-injector system in a free-piston engine compressor according to claim 6 wherein stop means is provided in said first and second chambers controlling the flexture of said diaphragm and the quantity of fuel injected.

8. A fuel injector for internal-combustion engines having a combustion cylinder comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of chambers; a plunger valve reciprocable in a bore in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; actuator means engaging said plunger and operable to move said plunger in the opposite direction; means for supplying air to said plunger bore at superatmospheric pressure; means for supplying fuel to said plunger bore at said pressure; communication means between a first one of said chambers and said plunger bore; communication means between said discharge outlet and said plunger bore; communication means i2 between a second one of said chambers and said plunger bore; and a first and second conduit in said plunger, said first conduit in reciprocation of said plunger sequentially registering with said fuel supply means at a first position, between said first chamber communication means and said discharge outlet communication means at a second position, and with said plunger bore at a third position, said second conduit sequentially registering between said first chamber communication means and said air supply means at said first position, with said plunger bore at said second position, between said first chamber communication means and said second chamber communication means at said third position, said second chamber communication means being open to the atmosphere at said first position.

9. A fuel injector for internal-combustion engines according to claim 8 wherein said first and third positions are terminal positions in said reciprocation of said plunger.

10. In a free-piston-engine compressor having a cylinder and piston, a fuel injection system, comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of chambers; a plunger valve reciprocable in a bore in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; a longitudinal cam groove provided on said piston; a cam follower in contact with said cam groove; a rocker arm engaging said cam follower and said plunger whereby on reciprocation of said piston, said cam groove, cam follower, and rocker arm cooperate to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; a fuel container having an air chamber and a fuel chamber; a flexible partition between said air chamber and said fuel chamber; communication means between said compressor and said air chamber whereby air supplied from said compressor flexes said partition to pressurize fuel in said fuel chamber; communication means between said fuel chamber and said plunger bore for supplying fuel to said plunger bore at superatmospheric pressure; communication means between said compressor and said plunger bore for supplying air to said plunger bore at said pressure; communication means between a first one of said chambers and said plunger bore; communication means between said discharge outlet and said plunger bore; communication means between a second one of said chambers and said plunger bore; and a first and second conduit in said plunger, said first conduit in reciprocation of said plunger sequentially registering with said fuel supply means at a first position, between said first chamber communication means and said discharge outlet communication means at a second position, and with said plunger bore at a third position, said second conduit sequentially registering between said first chamber communication means and said air supply means at said first position, with said plunger bore at said second position, between said first chamber communication means and said second chamber communication means at said third position, said second chamber communication means being open to the atmosphere at said first position.

11. A fuel injector for internal-combustion engines having a combustion cylinder comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a chamber therein; a plunger reciprocable in a bore in said body member; resilient means disposed in said frame urging said plunger in movement in one direction; actuator means engaging said plunger and operable to move said plunger in the opposite direction; means for supplying air to said plunger bore at superatmospheric pressure; means for supplying fuel at said pressure to said air supply means; means in said air sup ply mean for controlling fuel flow to said bore; communication means between said plunger bore and said chamber; communication means between said bore and said discharge outlet; and first and second conduits in said plunger, said first conduit in reciprocation registering with said air supply means and said chamber communication means at one position of said plunger, said second conduit registering with said chamber communication means and said discharge outlet communication means at a second position of said plunger, the registration of said first and second conduits alternating with the reciprocation of said plunger.

12, A fuel injector according to claim 11 wherein said fuel control means comprises an orifice and coacting needle valve.

13. In a free-piston engine compressor having a cylinder and piston, a fuel-injection system, comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a chamber therein; 15 a plunger reciprocable in a bore in said body member; resilient means disposed in said frame urging said plunger in movement in one direction; a longitudinal cam groove provided on said piston; a cam follower in contact with said cam groove; a rocker arm engaging said cam follower and said plunger whereby on reciprocation of said piston, said cam groove, cam follower, and rocker arm cooperate to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; an air supply line from said compressor to said plunger bore providing air at superatmospheric pressure to said bore; a fuel container having an air chamber and a fuel chamber; a flexible partition between said air chamber and said fuel chamber; communication means between said compressor and said air chamber whereby air from said compressor flexes said partition to pressurize said fuel in said fuel chambers; communication means betweensaid fuel chamber and said air supply line for supplying fuel to said air supply line at superatmospheric pressure; means in said air supply line for controlling fuel flow to said bore; communication means between said plunger bore and said chamber; communication means between said bore and said discharge outlet; and first and second conduits in said plunger valve, said first conduit in reciprocation registering with said air supply means and said chamber communication means at one position of said plunger, said second conduit registering with said chamber communication means and said dis charge outlet communication means at a second position of said plunger, the registration of said first and second conduits alternating with the reciprocation of said plunger.

14. A fuel-injector system in a free-piston compressor according to claim 13 wherein said fuel control means comprises an orifice and a needle valve.

15. In a free-piston engine having a cylinder, piston, 5 and compressor, a fuel injection system, comprising: a body member having a cavity for retaining pressurized fuel and having a discharge outlet in said cylinder; a fuel container having first communication means between said compressor and said fuel container and second communication means between said container and said cavity whereby gas supplied from said compressor pressurizes said fuel; a reciprocal plunger, having a conduit therein, disposed between said cavity and said discharge outlet to provide intermittent communication between said cavity and said discharge outlet; and actuator means engaging said plunger and operable to reciprocate said plunger.

16. In a free-piston engine having a cylinder, piston, and compressor, a fuel injection system, comprising: a body member having a cavity for retaining pressurized fuel and having a discharge outlet in said cylinder; a fuel container having a first chamber and a second chamber; a flexible partition between said first chamber and said second chamber containing fuel communication means between said compressor and said first chamber whereby gas supplied from said compressor flexes said partition to pressurize said fuel; communication means between said second chamber and said cavity for supplying pressurized fuel to said cavity; a reciprocal plunger,

having a conduit therein, disposed between said cavity and said discharge outlet to provide intermittent communication between said cavity and said discharge outlet; and actuator means responsive to movements of said piston engaging said plunger and operable to reciprocate said plunger.

17. In a free-piston engine compressor having a cylinder and piston, a fuel injection system comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of recesses; a plunger reciprocable in one of the recesses in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; an actuator means responsive to movements of said piston engaging said plunger to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; a diaphragm partitioning another of said recesses into a first and a second chamber; resilient means in said first chamber urging said diaphragm toward said second chamber; a fuel container having a gas chamber and a fuel chamber; a flexible partition between said gas and fuel chambers; communication means between said compressor and said gas chamber whereby gas supplied from said compressor flexes said partition to pressurize fuel in said fuel chamber; communication means between said fuel chamber and said second chamber for supplying fuel at a first pressure to said second chamber and to said plunger recess; communication means bet-ween said first chamber and said plunger recess, and between said plunger recess and said fuel discharge outlet; and conduit means in said plunger, said conduit means in reciprocation of said plunger alternately registering with said supply means and communication means, and alternating the pressure in said first chamber between said first pressure and the pressure of said combustion cylinder, said alternating pressure flexing said diaphragm to inject fuel into said combustion cylinder.

18. In a free-piston engine compressor having a cylinder and piston, a fuel injection system, comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a plurality of chambers; a plunger valve reciprocable in a bore in said body member; resilient means disposed in said body member urging said plunger in movement in one direction; and actuator means responsive to movement of said piston engaging said plunger to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; a fuel container having an air chamber and a fuel chamber; a flexible partition between said air chamber and said fuel chamber; communication means between said compressor and said air chamber whereby air supplied from said compressor flexes said partition to pressurize fuel in said fuel chamber; communication means between said fuel chamber and said plunger bore for supplying fuel to said plunger bore at superatmospheric pressure; communication means between compressor and said plunger bore for supplying air to said plunger bore at said pressure; communication means between a first one of said chambers and said plunger bore; communication means between said discharge outlet and said plunger bore; communication means between a second one of said chambers and said plunger bore; and a first and second conduit in said plunger, said first conduit in reciprocation of said plunger sequentially registering with said fuel supply means at a first position, between said first chamber communication means and said discharge outlet communication means at a second position, and with said plunger bore at a third position, said second conduit sequentially registering between said first chamber communication means and said air supply means at said first position, with said plunger bore at said second position, between said first chamber communication means and said second chamber communication means at said third 1 5 position, said second chamber communication means being open to the atmosphere at said first position.

19. In a free-piston engine compressor having a cylinder and piston, a fuel injection system, comprising: a body member having a discharge outlet in said combustion cylinder and being formed with a chamber therein; a plunger reciprocable in a bore in said body member; resilient means disposed in said frame urging said plunger in movement in one direction; an actuator means responsive to movements of said piston engaging said plunger to force said plunger against said urging of said resilient means providing reciprocating motion to said plunger; an air supply line from said compressor to said plunger bore providing air at superatmospheric pressure to said bore; a fuel container having a first communication means between said compressor and said fuel container and second communication means between said fuel container and said air supply line whereby said compressor pressurizes said fuel thereby supplying fuel to said air supply line at super- I? atmospheric pressure; means in said air supply line for controlling fuel flow to said bore; communication means between said plunger bore and said chamber; communication means between said bore and said discharge outlet; and first and second conduits in said plunger valve, said first conduit in reciprocation registering with said air supply means and said chamber communication means at one position of said plunger, said second conduit registering with said chamber communication means and said discharge outlet communication means at a second position of said plunger, the registration of said first and second conduits alternating with the reciprocation of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 2,447,513 Lewis Aug. 24, 1948 2,779,156 Huber Jan. 29, 1951 2,804,856 Spurlin Sept. 3, 1957

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