Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/20—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by changing the driving speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads

Definitions

• the mass would have to be reduced for instance to one quarter to obtain twice the cyclic speed which, in practice, would be a most difficult and most- likely impractical result to achieve.
• This invention involves the recognition of a need for a free piston
• the present invention accordingly includes a speed control device that allows changing the speed of a free piston engine compressor or similar energy absorbing device (EAD) within wide margins, or main ⁇ taining the speed of a free piston engine-driven electric generator or alternator within very narrow margins, independent from conditions 5-of the energy input section or the energy absorbing section which may, in the case of the generator require a very wide range of control to maintain a substantially constant speed, and in the case of compressor or heat pump EAD's, require substantial speed changes needed, for ex ⁇ ample, as compressor demand changes from low volume-high pressure to 0 -high volume-low pressure operation, and which in both instances is the very opposite of what the engine would do or the manner in which it would respond, if it did not include the control means and the structural arrangement and relative location of bounce chambers of this invention.
• EAD energy absorbing device
• the present invention thus provides a variable stroke free piston engine which can be selectively connected to any one of several dif ⁇ ferent energy absorbing devices, and in which the engine speed (fre ⁇ quency of reciprocation) can be controlled and adjusted in response to an extremely broad range of changes in the demands on a specific energy
• a bounce piston unit having oppositely directed and oppositely acting bounce piston faces compresses the air . or gas in one bounce chamber during a power piston expansion stroke of the piston rod assembly from the power piston end toward the EAD con ⁇ nection end and then compresses the air or gas in the other bounce chamber during the return (i,e. compression) stroke of the power piston.
• the invention provides a negative first bounce chamber at a relative location between one bounce piston working face and the power piston end of the piston rod assembly, and a positive second bounce chamber at a relative location between the other bounce piston working face and the EAD end of the piston rod assembly.
• the first and second bounce chambers are most efficient- ' ly and effectively provided by a single bounce cylinder in which op ⁇ posite faces osf only one double-acting bounce piston are used to separate the two bounce chambers, thus eliminating half of the fric- tional losses that would be developed between the usual piston rings ,and the inner bounce cylinder wall surfaces, if the bounce piston unit: had two piston members, and also minimizing the net pressure differen ⁇ tials between the two chambers separated by such a single bounce piston.
• the invention further provides control means for such machines which includes at least one pair of bounce chamber pressure control -openings (one opening in each bounce chamber), and at least one pair of variably (e.g., incrementally or intermittently) adjustable bounce pressure control valves (one for each of the bounce chamber control openings of said pair).
• Each control valve of said one pair when opened partially, fully, incrementally or intermittently, provides -for direct connection of the bounce chamber, through its bounce cham ⁇ ber pressure control opening, to the ambient atmospheric air outside the bounce cylinder.
• Each of said controls valves is further connected to its respective bounce chamber control opening for variably and sub ⁇ stantially simultaneously adjusting each of the variable pressure -control valves of said pair and thereby similarly changing (i.e. in the same direction, both upwardly or both downwardly) the respective bounce chamber working pressures in response to changes in the de ⁇ mands on the particular EAD involved.
• control valves of said one pair - are located and arranged to adjust the maximum outlet pressures for each bounce chamber. It is also possible to arrange such valves to adjust the minimum inlet pressures for each bounce chamber, or even to provide two such control valve pairs, one pair for inlet pressures and one pair for outlet pressures.
• the invention also provides for the further combination of means for relatively adjusting at least one pair of the respective variable pressure control valves in opposite senses, thereby making it possible 5 -to shif the successive top dead center positions of the power piston in its power cylinder in response to a signal from an engine efficiency sensing means which indicates relative efficiency or inefficiency of combustion and operation of the engine.
• a signal can be made available, for example, from a knock sensor of the type responsive to 0 -and indicative of incipient knocking in the power cylinder, i.e. at a top dead center position of the power piston just short of that at which actual knocking might occur.
• each face of the double- 5 -acting bounce piston substantially greater in cross section area than that of the power piston by a factor in the range from at least 1.5 to at least 4 times the power piston area, and in some applications as much as 10 times the effective power piston area.
• 35..assembly varies closely with the square root of the total mean or average force driving the reciprocating assembly.
• the cyclic speed can be substantially al ⁇ tered by raising or lowering the pressures in each of the bounce chambers, since the component forces driving the bounce piston are a ' product of their respective piston areas and the corresponding pressures acting on them.
• mean effective pressures of the engine or power cylinder it can be shown that to double the -cyclic engine speed the bounce pressures PB will have to be increased by approximately three times the product of the mean effective engine pressure MEP times the ratio of the power piston area AE over the bounce piston area AB, i.e. PB is nearly equal to 3 MEP (AE/AB) .
• a further advantage in having the bounce chamber of the speed con- -trol section independent of the selected energy absorbing device, such as the compressor piston of a compressor or heat pump, is that the maximum pressures in the bounce chambers of the speed control section of the present invention can be kept to a minimum.
• the energy absorbing device to be removably attached to the outer end of the engine power assembly includes a com- ⁇ a pressor piston in a compressor cylinder, this compressor cylinder can also be constructed to provide a further (third) bounce chamber between the outer end of the engine and the compressor piston.
• Such a third bounce chamber can be used at the back side of the compressor piston in such a way as to help keep the bounce pressures in the two speed control bounce chambers of the engine substantially equal and thus to their lowest possible maximum cylinder pressure.
• one or both chambers of the speed control bouncer can be made to temporarily act as compressors until the refrigerant compressor is able to assume the power input from the driver or power section. Similar situations exist, for example, in free piston engine electric generators which • ceuld be similarly controlled by the speed control bouncer.
• the invention is thus not merely in the use or control of bounce piston control pressures alone or the use of two bounce cham ⁇ bers as a control. It also involves the specific relative location of bounce piston faces and bounce chambers to provide adequate con ⁇ trol piston areas without blocking or limiting the area for the EAD connection end of the engine. This further makes possible the pro- vision and use of an optimum number of piston faces and an optimum assignment of power and control functions to such piston faces, including the allocation of speed control functions to the specif ⁇ ically located oppositely-acting bounce chambers and bounce piston faces and the possibility of using ambient atmospheric air as a control fluid to provide a wide range of control in a manner com ⁇ patible with the selective attachment of different energy absorb ⁇ ing devices.
• Fig. 1 of the accompanying drawing is a schematic showing of one embodiment of the invention
• .. Fig. 2 is a work diagram in which the work is plotted vertically with reference to the expansion and compression strokes plotted horizontally for the power piston of an engine unit
• Fig. 3 is a work diagram for a bouncer unit
• 'Fig. 4 is a work diagram for a compressor unit
• Fig. 5 is a work diagram for a scavenging unit
• Fig. 6 is a work diagram for a bouncer unit having different inlet and outlet valve pressure settings from that of Fig. 3 allow ⁇ ing the bouncer at these settings to act as a compressor
• -Fig. 7 is a work diagram for a negative bouncer in the com*? pressor cylinder;
• Fig. 8 is a schematic showing of a modification of the inven ⁇ tion.
• Fig. 9 is a fragmentary sectional view of the modification of -Fig. 8, taken along line 9-9 of Fig. 8;
• Fig. 10 is a schematic showing, similar to Fig. 1, of another preferred embodiment of the invention.
• Fig. 11 is a schematic showing, similar to Fig. 1Q of another modification of the invention.
• - Fig. 11A is a partial schematic view of a preferred modification of the device of Fig. 11.
• the reference numeral 10 designates a free-piston -engine power cylinder which has a fuel inlet 11, an air inlet 12, an exhaust outlet 13 in a power section lOp of the cylinder, and conventional air inlet and outlet check valves in a scavenging air section 10s thereof.
• a power piston 15 is connected to a bounce bounce piston 16 by a piston rod 17 extending through a bearing 14 -in a wall between said pistons. Scavenging air may be suitably delivered from 10s to lOp through a conduit 12a by using the inner face (i.e. the right hand face, as viewed in Fig.
• a double-acting bounce piston 16 is located in a common bounce cylinder 18 having piston rod bearings 19 and 20 and air flow inlet openings 21 and 22, one on each side of piston 16. Piston 16 divides cylinder 18 into a negative first bounce chamber 18n and a positive second bounce chamber 18p, respectively.
• the respective bounce chambers are provided with pressure control means which include a pair of pressure control inlet openings 21 and 22, one in each bounce chamber, and a pair of pressure con ⁇ trol outlet openings 25 and 26, one in each bounce chamber.
• An adjustable pressure-actuated inlet control or check valve 23 is 0 -located in opening 21, and a similar or identical adjustable check valve 24 is located in opening 22.
• Outlets 25 and 26 are provided with variably adjustable pressure-actuated high pressure outlet control valves 27 and 28 to control air flow out of the cylinder and thereby the maximum working pressures and the bounce energy in the
• An energy absorbing device illustrated as a compressor cylinder 29 • at the cuter end of the engine,has an- outlet opening 30witha check valve 31 therein, an inlet opening 32 with a checkvalve 33 therein and a compresso piston 34 therein.
• Piston 34 is connected to bounce piston 16 by a pist 0 ⁇ o ⁇ 35, preferably through a bellows seal 36at theotherend ⁇ £ cylinder 29.
• Inlet valves 23 and 24 have tension springs for normally clos ⁇ ing the valve elements therein, each being manually adjustable to change the pressure drop across each valve. In the simplest case, where the clearance volume in each of the two bounce chambers is
• the boxes 23a and 24a have conventional manually adjustable means therein for adjustably changing the spring tension. To change the spring tension automatically, the adjustable means may be actuated by a
• a conventional speed responsive or temperature responsive sensor 37 may be connected to controls
• the senor may be responsive to compressor flow, changes in temperature needs and/or cyclic speed requirements o ⁇ the engine, or to com ⁇ binations thereof, or to other suitable control signals.
• the sensing means itself may be of a known type but is connected through a mechanism 38 which variably and substantially simultaneously and similarly (i.e. in the same- direction) adjusts each of the variable pressure control valves 23 and 24 and thereby similarly changes the respective working pressures in bounce chambers 18n and 18p. Suitable mechanisms are further described herein in connection with Figs. 10 and II. For otherwise substantially constant conditions of the machine of Fig.
• the present control means includes bleed means providing a substantially continuously open limited leakage path of small effective cross section primarily out of each bounce chamber. Such leakage paths are provided, for example, by the small bleed openings L8a and 18b iu Fit',. 1.
• valves 23,24,27 aa ⁇ 28 are Located and constructed for direct connection between the corresponding bounce chambers and ambient atmos ⁇ pheric air outside the bounce cylinder.
• Non-pressure-actuated valves may also be provided in series with or in lieu of the valves 23 and 24.
• the outlet valves 27 and 28 have compression springs therein for nor ⁇ mally holding the valves closed. They likewise have conventional means 25a and 25b for adjusting their compression. Automatic means can be pro ⁇ vided as shown in Fig. 11 to adjust these valves in a manner similar to that for valves 23 and 24. Such adjustment may be in addition to or in place of the means for valves 23 and 24. In many machines it is most effective to provide such automatic variable adjustment and control for ⁇ the outlet valves 27 and 28 only, nad insure proper functioning by providing any required flow into the bounce chambers through preset inlet check valves 23 and 24, in which case the small bleed openings 18a and 18b can be eliminated.
• combustion of fuel in the chmaber to the left of piston 15 causes the power assembly (power piston 15, bounce piston 16 and piston rod 17,35) and attached compressor piston 34 to move to the right. This causes a build-up of pressures in the scavenge air cham ⁇ ber 10s to the right of piston
• valves in the bouncer unit may be adjusted temporarily to cause the bouncer to act as a compressor and, thereby, temporarily increase the load to absorb the energy of the engine.
• the piston rod and power assembly in the engine of Fig. 1 thus provides two pistons with a total of four working faces, one for the power section, one for the scavenging section, and two for the bounce chambers of the control section.
• this assembly is con- nected to the working piston of a compressor type of energy absorb ⁇ ing device, the two additional piston faces provided by such working piston can also be fully utilized, i.e.. one face as a compressor working face, and the other face as a bounce control piston face for a further (i.e. third) bounce -chamber control section.
• a maximum range of speed control is obtainable within the general constraints imposed by the maximum allowable cylinder pressures and space limitations.
• Fig. 1 basically the same in relative location and control of bounce chambers as that of Fig. 1 in that it has a power cylinder 110 at one end, a connection to a compressor 129 at the other end, and a bouncer assembly 118 with separate negative and positive bounce cylinders 118a and 118b providing negative and positive bounce
• a sensor and control means 137 controls the air pressures in the bounce chambers in response to engine speed. Air flows from auxiliary compressor 140, . through conduit 140a to sensor, controlled means 137 and
• conduits 138 25 through conduits 138 to valve adjusters 123a and 124a.
• the negative bounce chamber is designated by numeral 118n and the positive by 118p. Other elements similar to those of Fig. 1, have numbers differing by 100.
• Fig. 10 is a schematic diagram similar to Fig. 1, showing another preferred emboidment of the present invention, in which the variable stroke free piston machine includes a power assembly with a piston 215 at one end of the axially movable piston rod 217, 235 and with a connection means 235a at the second or ⁇ ⁇ .Outer end of the piston rod for selective and removable driving connection to an appropriate energy absorbing device 229 which could be the piston of a compressor, as in Fig. 1, or an axially reciprocable electric gen ⁇ racor member, or the piston of a heat pump assembly.
• an appropriate energy absorbing device 229 which could be the piston of a compressor, as in Fig. 1, or an axially reciprocable electric gen ⁇ racor member, or the piston of a heat pump assembly.
• the power assembly in ⁇ cludes a double-acting bounce piston 216, which moves back and forth axially within a bounce cylinder 218, so that the respective faces 216n and 216p of piston 216 divide the bounce cylinder 218 into an inner or negative first bounce chamber 218n between the power piston and the bouncer piston, and an outer or positive second bounce chamber 218p on the opposite side of the bouncer piston 216, i.e. between the bouncer piston and the outer piston rod end carrying the load connection 235a for the working member of the energy absorbing device or load.
• the effective cross sectional area of the double-, acting bouncer piston 216 is substantially greater than that of the power piston, as already described, by a factor in the range from at least 1.5 to at least 4 times the area of the power piston 215.
• Fig. 10 which correspond to similar elements in Fig. 1 are given numbers in the 200 series, with the last two numbers corresponding generally to the similarly numbered parts in Fig. 1.
• the controls for the bounce chambers 218n and 218p include respective inlet openings 221 and 222 controlled by spring loaded inlet valves 223 and 224. These valves are biased down ⁇ wardly in Fig. 10 by adjustable springs 223a and 224a, which are connected respectively to the outer ends 241 and 242 of a generally horizontal control lever 243 pivoted on a horizontal (as shown) axis or shaft 244 carried by a vertically movable support slider 246.
• the vertical position of the movable support slider 246 may be adjusted by a vertically movable link 248 having its lower end pivoted on shaft 244 and its upper end 249 pivoted at 251 to one end of a two-armed lever 252 pivoted at an intermediate point 253 to another supporting bracket or frame member 254.
• lever arm 252 can be positioned along a scale 257 to estab ⁇ lish a relatively lower or higher pressure range simultaneously within each of the bounce chambers 218n and 218p, by pushing the pivot point 244 of the control lever 243 downwardly to a greater or lesser degree and thus increasing or reducing to a corresponding extent the tension of springs 223a and 224a which control the en ⁇ trance of atmospheric air to both bounce chambers at the low end of the pressure range which is achieved in such chambers as the volume of each bounce chamber approaches its maximum.
• the relative position of lever arm 252 may be controlled manually or automatically. In Fig.
• an automatic control is shown, in which the outer end 256 of lever arm 252 is connected as shown schematically at 258 to a speed responsive or temperature responsive controller shown schematically at 259.
• the respective bounce chambers 218 n and 218p are provided with constantly-open bleed openings or orifices 218a and 218b, respectively. These orifices provide limited but desirable and substantially continuous leakage of air from the bounce chambers to help reach the desired bounce pressures for which the inlet valves 223 and 224 are being controlled.
• the bounce chambers are provided with pressure relief openings 225 and 226, which are capable of substantial relief of pressure from stroke to stroke, at what ⁇ ever maximum pressure range has been established by the variable pressure relief valves 227 and 228.
• the relief pressure for these valves can again be set by manual adjustment of the spring tension therein or, as further described in Fig. 11, they may be controlled substantially simultaneously (due to the rapid back and forth strokes of the bouncer piston 216 with the piston rod assembly 217, 235) to control the apparatus by correspondingly limiting the maximum pressures within the two bounce chambers.
• the lever arm 243 includes" an integral downwardly projecting adjust ⁇ ing arm 261 perpendicular to arm 243 which can be controlled at its lower end 262 to rock the complete lever member 243, 261 in a clock ⁇ wise or counterclockwise direction around its supporting pivot 244, in response to control signals from another sensor, such as the well-known knock sensors for signaling incipient knocking of an engine within its power cylinder.
• the lower end 262 of lever arm 261 may be normally urged to the right by a connecting link 263 pivotally con ⁇ nected at 263a to a horizontally movable piston 264, urged to the right in Fig. 10 by spring 266 within cylinder 267.
• the rocking of the lever arm 261 to the right in Fig. 10 will reduce the tension of spring 224a and correspondingly increase the tension of spring 223a, so that air can enter bounce chamber 218p at a slightly higher pressure in chamber 218p and could enter bounce chamber 218n at a slightly lower pressure in chamber 218n than existed just before, such movement of lever end 262 to the right.
• lever arm 261 can be pushed to the left in Fig. 10 by ⁇ admission of air under appropriate pressure to the control chamber 268 at the right ⁇ f piston 264.
• Such pressure can be applied under the control of a normally closed solenoid valve 269 which can be opened to admit compressed air or gas, either from the scavenge pump of such an engine or from any other source of pressure indicated generally at 271, which supplies the necessary pressurized control air or gas through check valve 272.
• the chamber 268 in which piston 264 can be moved against the urging of spring 266 by an increase of pressure within the chamber is also provided with a bleed opening 273, in order to per ⁇ mit, reduction of pressure in chamber 268 and corresponding movement of piston 264 back to the right under the influence of spring 266, to the extent that the normally closed solenoid valve 269 is not b ' eing actuated in response to a signal indicating incipient knock at the power cylinder.
• Such a knock sensing de-vice is indicated . schematically at 274 in Fig. 10.
• the signal from a well-known type of knock sensor will open the normally closed solenoid valve to increase the pressure in chamber 268, move piston 264 and lever arm 262 gradually to the left, and thus rock the lever arm 243 so as to in ⁇ crease the tension of spring 224a, decrease the tension of spring 223a, and thus subs antially simultaneously (because of the fre- quency of the engine strokes) make it more difficult for air to enter the bounce chamber 218p, less difficult.for air to enter,
• valve 269 When the knock sensor signal is thus eliminated, valve 269 will resume its normally closed position, and the escape of pressure from chamber 268 through bleed opening 273 will reverse the control process, all of which happens within short time intervals, in view of the relatively high frequency of reciprocation of the piston rod in this type of free piston engine.
• the "top-dead center" position of the power piston will intermittently (within these short time intervals) oscillate between the incipient knock position and a small distance short of this point of maximum engine efficiency, irrespective of where the position of incipient knocking may occur under the influence of operating conditions such as engine intake air temperature, air-to-fuel ratio, throttle position, octane number of fuel, altitude and others.
• operating conditions such as engine intake air temperature, air-to-fuel ratio, throttle position, octane number of fuel, altitude and others.
• the device of Fig. 10 further emphasizes the advantages of providing a single bounce cylinder with closed ends through .which a piston rod assembly, with a power piston at one end and an energy absorbing load device connection at the other end can reciprocate axially, and in which the rod is provided with a double "acting bounce piston inside the bounce cylinder, which defines two bounce chambers of substantially equal circular cross section.
• a double "acting bounce piston inside the bounce cylinder which defines two bounce chambers of substantially equal circular cross section.
• bounce piston faces cross- sectional areas which are not only substantially equal to each other in the respective bounce chambers, but are also substantially larger, as shown in Figs. 1 and 10, than the area of the power piston, makes it possible to provide total bounce chamber forces (i.e. piston area times instantaneous pressure) great enough to establish and/or maintain the desired high degree of control over the operation of the piston rod and power assembly under the varying load and frequency conditions required by whatever -specific energy absorbing device (e.g., .compressor piston, heat pump assembly piston, or axially movable electric generator member) is selected for connection to the outer end of..the piston rod.
• a -specific energy absorbing device e.g.compressor piston, heat pump assembly piston, or axially movable electric generator member
• the small constantly-open bleed openings such as 218a and 218b, further provide limited inlet and outlet functions in each bounce chamber, and their function should be included in certain cases.
• variable pressure bounce chamber valves Such function can also be achieved as part of the construction or operation of the variable pressure bounce chamber valves, or by limited leakage along the shaft seals at the respective end walls of the bounce chambers, or even by limited leakage around the periphery of the bounce piston from one bounce chamber to the other.
• desired functions of such bleed openings should be supplemented (or provided) by at least one pair (one in each bounce chamber) of variable bounce chamber pressure inlet control valves, or one pair (one in each bounce chamber) of variable bounce chamber pressure relief valves, or preferably by both such pairs.
• Fig. 11 shows an embodiment of the invention in which the desired control of the free piston machine is specifically achieved by a pair of pressure relief outlets 325 and 326 (one in each of the bounce chambers 318n and 318p). These pressure relief outlet means are controlled by variable pressure outlet valves 327 and 328 as shown schematically in Fig. 11.
• a pair of small constantly-open bleed openings 318a and 318b (one in each of the bounce chambers 318n and 318p) , is also provided. Both the bleed openings and the variable pressure relief valves are shown, for example, as located in the axial end walls of bounce chamber 318, which are also provided with central bearing portions and seals at 319 and 320 to receive the axially movable piston rod assembly 317, 335.
• This rod has a power piston 315 at its inner end and a connection 335a at its outer end for readily removable connection to a moving member 334 of a selected energy absorbing device 329 which is also removably secured to the outer end of the machine at 341.
• Fig. 11 Elements in Fig. 11 which correspond to similar elements in other figures are given numbers in the 300 series, with the last two numbers corresponding generally to the similarly-numbered parts in Fig. 1.
• the power piston 315 moves axially within a power cylinder 310 and compresses the appropriate fuel mixture in combustion chamber 310p during a compression stroke of the power assembly 317, 335 and its associated parts from right to left .in Fig. 11. Combustion of the fuel mixture in chamber 310p then drives the power piston315 and associated piston rod to the right in Fig. 11 in the appropriate power stroke needed for operation of the energy absorbing device member 334.
• the double-acting bounce piston 316 carried by the piston rod divides the cylindrical bounce chamber 318 into a first bounce chamber 318n toward the power piston end of the machine and a second bounce chamber' 318p toward the load connection means at the other end of the machine.
• These bounce chambers are used for control of the machine, and the controls include the constantly open restricted openings 318a and 318b, respectively (one in each chamber) in combination with the pair of pressure relief openings 325 and 326 controlled by variable pressure valve members 327 and 328, respec ⁇ tively described above.
• the closing forces of the valves are adjustably set by spring members 343 and 344 which are compressed between the valves and two respective control abutments 345 and 346.
• Abutment 345 projects upwar Ly from n slLdcr member 347 which is supported for relative sliding within the hollow receiving chamber 348 of a telescoping outer slider member 349.
• Slider 349 is relatively slidable along the same axis as member 347 within the channel 351 of a slide support 352 secured to the bottom of bounce cylinder 318 or to an appropriate frame member of the engine.
• the inner slider member 347 is provided with an extension shaft 354 extending axially through the outer slider 349 to a piston 356 within a control cylinder 357 at the outer end of slider member 349 which carries abutment 346.
• pressure may be increased within the cylinder chamber 358 at the left side (as viewed in Fig. 11) of piston 356.
• variable pressure regulator valve 359 connected to a source 360 of pressurized air or gas can feed such pressurized fluid through inlet 362 into chamber 358 in response to signals from a suitable sensor shown schematically at 361, such as a signal from a speed responsive sensor indicating an undesired de ⁇ crease in speed or frequency of the free piston machine.
• a vent 355 keeps the outer end of cylinder 357 at ambient pressure, so piston 356 is free to move out in response to pressure increases in chamber 358.
• The. increased valve closing pressures- of springs 343 and 344 can thus provide increased maximum pressure levels within the respective bounce chambers 318n and 318p to increase the speed of engine operation until the signal from the speed regulator permits regulator valve 359 to close. At that point, pressure will be relieved within chamber 358 of the slider cylinder 357 by means of the small bleed orifice 363. If the pressure drops to a point where the sliders move apart far enough to cause another undesired drop in engine speed, the control process just described will be repeated, so that the engine speed may vary slightly in a cyclical manner close to the desired engine speed. This control arrangement responds to undesired decreases in speed, but it should be understood that such a control system could also be made responsive to undesired increases in engine speed.
• the slider members 347 and 349 and their spring-controlling abutments 345 and 346 can be moved axially as a unit to increase the relief pressure imposed by spring 342 and simultaneously decrease the spring pressure imposed by spring 344, or vice versa.
• a piston 364, rigidly connected to the outer end of slider 349 is received in a control cylinder 367 fixed to a stationary engine part or frame at 366.
• a spring 365 between the outer end of slider 349 and the inner end (left end, as viewed in Fig. 11) of fixed cylinder 367 normally urges the total assembly of sliders 347 and 349 in a direction (left in Fig. 11) to apply maximum spring pressure at 343 on relief valve 327 and to apply minimum spring pressure at 344 on relief valve 328.
• the pressure in cylinder chamber 368 may be controlled, for example, in response to signals from a known knock sensor 374 of the type described in connection with Fig. 10.
• a signal from such an incipient knock snnsor can open a solenoid-controlled valve 369 to feed compressed air or gas from an appropriate source 371 (such as the scavenge pump chamber 310s or any other suitable source of pressure) through a check valve 372 into the inlet of chamber 368.
• Valve 369 will then close, and bleed orifice 373 will provide for slow release of pressure from chamber 368 to let the sliders move back and increase the bounce relief pressure at valve 326, so that the engine operation can again approach the incipient knocking- point, where operation is generally believed to be most efficient.
• the upper dead center position of power piston 315 can cycle within a narrow range close to the incipient knock point to maintain the desired efficiency of engine operation.
• control systems shown in Fig. 11 operate to provide the desired bounce chamber pressure ranges by variably controlling the maximum pressures within such chambers, without relying on the controls at the low pressure ends of such ranges as more fully described in connection with Fig. 10.
• Fig. 11A shows a preferred modification of the device of Fig. 11, in which the pair of small constantly open bleed openings 318a and 318b are replaced by inlet openings 321 and 322 controlled by one-way inlet valves 323 and 324 for the respective bounce chambers 318n and 318p.
• the inlet pressure at which the inlet valve will open may be preset, or variably adjusted as shown schematically at 323a and 324a, and the inlet valves are provided with restricted orifices 323b and 324b which are "upstream" from the bounce chamber inlet openings and one-way val-ve portions.
• Such restricted orifices are open directly to the ambient air at atmospheric pressure and are restricted primarily to limit the rate at which air can be sucked into the respective bounce chambers during the intervals in which the one-way check valves are open.
• Such restricted orifices may be as small as .02 inches in effective diameter, to limit the inward flow of ambient air when the inlet valves are opened.
• the inlet valves are thus useful in providing for limited replacement of control air within the. respective bounce chambers, while the major control of bounce chamber working pressures is achieved as described in connection with Fig. 11 by the indicated variable adjustments of the maximum pressures at which the respective bounce chamber exhaust valves 327 and 328 will be opened.
• the inlet check valves can be set, however, to let the control means work with higher bounce pressures.
• Figs. 11 and 11A have both safety and operating advantages in providing a particularly wide range of bounce chamber control pressures primarily by controlling the maximum pressures in such chambers.
• the present invention provides a wide range of control possibilities by providing at least one "negative" or inner bounce chamber positioned toward the power piston end of such an engine, i.e. between a bounce piston face on the piston rod of the engine and the power piston itself, in combination with a so-called "positive" or outer bounce chamber positioned toward the outer end of the engine, i.e. between the inner bounce chamber and the load connection means at the other end of the piston rod of the free piston engine assembly.
• the available flexibility of control provided by such relative locations and by the indicated relative cross sectional areas of the bounce chambers helps to make possible the use of different energy absorbing devices with the same basic power unit, by selectively and removably connecting such different devices, as shown schematically at 335a and 341 in Fig. 11, to the closed outer end of the outer bounce chamber or to some other appropriate frame part, and by using the same power assembly and piston rod 317, 335 to drive the desired movable member 334 of the particular energy absorbing device chosen for a specific application.
• the energy absorbing device is a working compressor (or pump), as specifically shown in Fig.l
• the invention provides a relative location of engine parts which permits the compressor or pump chamber to be separated from, and thereby effectively sealed off from the engine speed controlling bounce cylinders.
• This permits use of a working fluid in the compressor or pump chamber which is different from e.g. incompatible with the controlling fluid, such as air, which is used in the engine bounce cylinders.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Valve Device For Special Equipments (AREA)
• Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
• Control Of Velocity Or Acceleration (AREA)
• Control Of Electric Motors In General (AREA)
• Actuator (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Supercharger (AREA)
• Fluid-Pressure Circuits (AREA)
• Pistons, Piston Rings, And Cylinders (AREA)
• Sealing Devices (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Publications (3)

Family

ID=22188885

Family Applications (1)

Country Status (10)

Families Citing this family (7)

Citations (1)

Family Cites Families (9)

• 1985
  • 1985-10-10 HU HU85419D patent/HUT48949A/hu unknown
  • 1985-10-10 JP JP60505196A patent/JPS63502523A/ja active Pending
  • 1985-10-10 BR BR8507298A patent/BR8507298A/pt unknown
  • 1985-10-10 AU AU50942/85A patent/AU581044B2/en not_active Ceased
  • 1985-10-10 EP EP85905954A patent/EP0246227B1/fr not_active Expired - Lifetime
  • 1985-10-10 WO PCT/US1985/001997 patent/WO1987002423A1/fr active IP Right Grant
  • 1985-10-10 DE DE8585905954T patent/DE3584293D1/de not_active Expired - Lifetime
  • 1985-10-10 AT AT85905954T patent/ATE68037T1/de not_active IP Right Cessation
• 1987
  • 1987-06-09 DK DK294187A patent/DK294187A/da not_active Application Discontinuation
  • 1987-06-09 NO NO87872410A patent/NO872410L/no unknown

Patent Citations (1)

Also Published As

Similar Documents

Legal Events