Classifications

• • 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
  • F02B75/045—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of a variable connecting rod length
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
  • F01B9/00—Reciprocating-piston machines or engines characterised by connections between pistons and main shafts, not specific to groups F01B1/00 - F01B7/00
  • F01B9/04—Reciprocating-piston machines or engines characterised by connections between pistons and main shafts, not specific to groups F01B1/00 - F01B7/00 with rotary main shaft other than crankshaft
  • F01B9/047—Reciprocating-piston machines or engines characterised by connections between pistons and main shafts, not specific to groups F01B1/00 - F01B7/00 with rotary main shaft other than crankshaft with rack and pinion
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K15/00—Check valves
  • F16K15/18—Check valves with actuating mechanism; Combined check valves and actuated valves
  • F16K15/182—Check valves with actuating mechanism; Combined check valves and actuated valves with actuating mechanism
  • F16K15/1823—Check valves with actuating mechanism; Combined check valves and actuated valves with actuating mechanism for ball check valves

Definitions

• the present invention relates to a hydraulic power unit for a variable compression ratio engine comprising a compressed air oil pressure accumulator, and a multi-stage pressure booster provided with at least one stage for adjusting, in operation and with a low energy consumption, the pressure applied to the pressure cylinders of said engine.
• the mechanical transmission device for variable compression ratio engine comprises a piston secured in its lower part of a transmission member cooperating on the one hand with a device rolling guide, and secondly with a toothed wheel secured to a connecting rod for transmitting the movement between said piston and said connecting rod.
• the mechanical transmission device for variable compression ratio engine comprises at least one cylinder in which moves a piston which is secured in its lower part, an organ transmission cooperating on the one hand by means of a small rack with a rolling guide device, and on the other hand by means of another rack of large dimension with a toothed wheel secured to a connecting rod.
• Said mechanical transmission device for variable compression ratio engine also comprises at least one control rack cooperating with the gear wheel, means for fixing the piston on the transmission member which provide a clamping preload, connecting means which make it possible to stiffen the teeth of the racks, and means for reinforcing and lightening the structure of the toothed wheel.
• variable compression ratio engine has at least one pressure cylinder which allows the rolling surfaces to remain permanently in contact with each other in order to control the acoustic emissions of said engine and increase the manufacturing tolerances of its cylinder block.
• control rack of the variable compression ratio engine is controlled by a control jack which comprises a hydraulic fluid inlet under pressure intended to compensate possible leakage of said control cylinder, and to ensure a pre-charge pressure to increase the accuracy of maintaining the setpoint in the vertical position of said control cylinder by reducing the effects of the compressibility of the oil, and to avoid any cavitation phenomenon inside the chambers of said cylinder.
• variable compression ratio engine has as many pressing cylinders and control cylinders it has cylinders.
• variable compression ratio engine comprises a hydraulic unit provided on the one hand, to provide his pressure cylinder (s) pressure hydraulic system necessary for their operation, and secondly, to provide his or her cylinder (s) control the hydraulic pressure necessary to compensate for their possible hydraulic leaks and increase their accuracy.
• the hydraulic pressure supplied to the control cylinder can also serve to increase the speed of movement of said control cylinder during maneuvers to increase the volumetric ratio of the variable compression ratio engine.
• said hydraulic pressure is applied to the upper face of the upper rod of the control cylinder by means of a chamber arranged in the cylinder head of said cylinder.
• the hydraulic unit comprises a first pressure accumulator said "main", said accumulator being fed by a hydraulic pump and constituting a reserve of oil under high pressure .
• the hydraulic unit also comprises a second pressure accumulator called "servo" connected to (x) cylinder (s) pressure (s) hydraulic (s) of the variable compression ratio engine.
• servo second pressure accumulator
• the average pressure of said servocontrol battery is adjusted to meet the operating conditions of said engine by means of hydraulic valves for charging and discharging.
• the charge valve is used to transfer oil from the main accumulator to the accumulator to increase the pressure, while the discharge valve transfers oil from the servo accumulator to the variable compression ratio engine oil sump to lower the pressure said servo accumulator.
• the hydraulic unit comprises a third pressure accumulator said "leak compensation" connected to the control cylinders of the variable compression ratio engine, the pressure in said leak compensation accumulator being kept approximately constant by a hydraulic expansion valve which can supply oil to said leakage compensation accumulator, said oil from the main accumulator.
• the hydraulic unit according to the invention is designed to solve a set of problems related to the hydraulic unit as described in French patent FR 2,896,539 in the name of the applicant, among which:
• the spring-loaded pressure accumulators as described in the patent application FR 2,896,539 are robust and durable, but they have the disadvantage of a high stiffness which generates large pressure variations in the control cylinders when these ci move to adjust the compression ratio of the variable compression ratio engine or in the pressure cylinders as they move to follow the movement of the moving parts of said engine.
• to obtain a low stiffness of said spring pressure accumulators it is necessary to increase their size and weight so that they become too heavy and difficult to accommodate in the oil sump of said engine.
• any modification of the internal pressure of said accumulators, necessary in particular for controlling the pressure applied to the pressure cylinders as a function of the speed and the load of the engine with variable compression ratio, induces a significant energy loss by virtue of high pressure oil qualities that must be introduced into said accumulators or extract said accumulators.
• the pressurized gas accumulators separated from the hydraulic fluid by a membrane as described in the patent application FR 2 896 539 have a low stiffness which is advantageous, but they have the disadvantage of not being sufficiently durable . Indeed, in the current state of the art, the rubber or polymer membranes they incorporate become porous and degrade rapidly so that it is impossible for them to provide a reliable service throughout the life of the product. variable compression ratio engine.
• the pressure regulation in the pressure cylinders is effected by means of two valves, one for transferring oil from the main high pressure accumulator to the accumulator servocontrol to increase the pressure in the pressure cylinders, the other for transferring oil from the servo battery to the engine oil sump to reduce the pressure in the pressure cylinders.
• This method of adjusting the pressure in the pressure cylinders has the disadvantage of consuming a lot of energy and using fast and accurate solenoid valves whose cost is high.
• a single pressure reserve instead of three in the case of the French patent FR 2,896,539 in the name of the applicant, said reserve having a low stiffness and offering on the one hand, small pressure variations in the control cylinders in as a function of the volumetric ratio variations, and on the other hand, small pressure variations in the pressure cylinders as a function of the amplitude of the operating stroke of said pressure cylinders resulting from the geometric defects of the moving coupling and / or crankcase of engine with variable compression ratio;
• variable compression ratio hydraulic power unit comprises a compressed air oil pressure accumulator connected firstly to the inlet of a multi-stage pressure amplifier comprising at least one stage and whose pressure the output is applied to the pressure cylinder (s) of said motor, said output pressure being controlled by at least one solenoid valve, and secondly connected to the control cylinder (s) of said motor.
• variable compression ratio hydraulic power plant according to the present invention comprises other essential features which are described and protected in the dependent claims directly or indirectly dependent on the main claim.
• Figure 1 is a perspective view illustrating the main components of a variable compression ratio engine and the location of the hydraulic power plant according to the present invention in said engine.
• FIG. 2 is a view illustrating the schematic diagram of the hydraulic power unit for a variable compression ratio engine comprising a compressed air oil pressure accumulator, and a multi-stage pressure booster provided with at least one stage for adjusting in operating and with low energy consumption the pressure applied to the pressing cylinders of said engine.
• Figures 3 and 4 are perspective views showing an example of the arrangement of the various components of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figure 5 is a bottom view illustrating the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figure 6 is an exploded perspective view showing the various elements of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figure 7 is an exploded perspective view showing the multistage pressure booster of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figures 8 and 9 are sectional views respectively longitudinal and transverse illustrating the multistage pressure amplifier of the plant hydraulic motor for variable compression ratio according to the present invention.
• Figure 10 is an exploded perspective view showing the air pump of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figures 11 to 14 are views showing the different stages of operation of the air pump of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figure 15 is an exploded perspective view illustrating the replenishing solenoid valves and the common replenishment ramp of the variable compression ratio hydraulic power plant according to the present invention.
• Figure 16 is an exploded perspective view showing the input pressure selection slider of the control cylinders of the hydraulic power plant for variable compression ratio engine according to the present invention.
• Figure 17 is a sectional view showing the lubricating oil pressure accumulator of the hydraulic power plant for variable compression ratio engine according to the present invention.
• FIG. 1 shows an engine block 100 comprising at least one cylinder 110 in which a piston 2 moves by means of a transmission device 1 and pressure means which make it possible to hold the main moving components in position. a variable displacement ratio engine in their cylinder block.
• the mechanical transmission device 1 comprises in the lower part of the piston 2 a transmission member 3 secured to said piston and cooperating, on the one hand with a rolling guide device 4, and on the other hand with a toothed wheel 5.
• the toothed wheel 5 cooperates with a connecting rod 6 connected to a crankshaft 9 in order to carry out the transmission of the movement between the piston 2 and said crankshaft.
• the toothed wheel 5 cooperates opposite the transmission member 3 with another rack called control rack 7 whose vertical position relative to the engine block 100 is controlled by a control device 12 comprising a control cylinder 8, whose piston cylinder 13 is guided in a cylinder cylinder 112 arranged in the engine block 100.
• the cylinder cylinder 112 is closed in its upper part by a cylinder head 113 which is screwed on the engine block 100.
• the engine block 100 is secured to a support 41 comprising racks 46 ensuring the synchronization of the displacement of the roller 40 of the rolling guide device 4 with that of the piston 2.
• a hydraulic unit 200 consisting of different autonomous and independent components can be installed either inside the engine block 100 or at any point in the engine compartment of the vehicle or the vehicle itself.
• the various components of the hydraulic unit 200 may be wholly or partly housed in the oil sump 203 of the engine block 100.
• FIGS. 2 to 6 show a hydraulic unit 200 for a variable compression ratio engine whose various components may be wholly or partly housed in the oil sump 203 of the engine block 100.
• the hydraulic unit 200 comprises a compressed air oil pressure accumulator 251 connected to the inlet of a multi-stage pressure amplifier 241 comprising at least one stage whose output pressure is applied to the cylinder (s) pressing (s) 170 of said motor, said output pressure being controlled by at least one solenoid valve 285 stage selection.
• the compressed air oil pressure accumulator 251 of the hydraulic unit 200 is connected to the control cylinder (s) 8 of said engine.
• the hydraulic unit 200 comprises at least one pressurized air reserve 244 comprising at least one pressure sensor 245 for measuring the pressure prevailing in said reserve.
• the pressurized air reserve 244 comporte at least one solenoid valve air discharge, to lower the pressure in said reserve.
• this discharge solenoid valve can be replaced by a discharge valve which lets air pass beyond a certain pressure and this, in order to limit the maximum pressure prevailing in the air reserve 244 .
• the pressurized air reserve 244 of the hydraulic unit 200 for a variable compression ratio engine comprises at least one temperature sensor 248.
• the hydraulic unit 200 comprises at least one oil tank 249 pressurized by the pressurized air reserve 244.
• the oil reservoir 249 of the hydraulic power station 200 for variable compression ratio engine comprises an oil level sensor 250, for measuring the amount of oil contained in said reservoir.
• the measurement of the quantity of oil contained in the oil reservoir 249 can be based on the detection, via a microphone, of the natural frequency of the volume of air vibrated by an acoustic generator, or based on one or several resistances whose electrical conductivity is measured as a function of their temperature induced by their immersion rate in the oil.
• the oil reservoir 249 comprises at least one pressure sensor for measuring the pressure in said reservoir.
• the oil level sensor 250 of the oil tank 249 of the hydraulic unit 200 consists of at least one float 252 connected to a position sensor 253.
• the hydraulic unit 200 comprises at least one high-pressure oil pump 254 driven by the variable compression ratio engine, the oil supply of said central unit 200 by said oil pump 254 being controlled by a high pressure oil pump solenoid valve. 255.
• the hydraulic unit 200 for variable compression ratio engine comprises at least one air pump 256 whose output is connected to the pressurized air reserve 244.
• the air pump 256 of the hydraulic unit 200 is actuated by the oil from the high pressure oil pump 254 when said oil is directed to said air pump 256 by an air pump replenishing solenoid valve 257.
• the hydraulic power plant 200 for variable compression ratio engine comprises a circuit separator 300 which comprises a separator piston 301 housed in a separation cylinder 302.
• the circuit separator 300 comprises a separator piston 301 housed in a separation cylinder 302.
• the circuit separator 300 prevents the oil contained in the lubrication circuit of the variable compression ratio engine and that contained in the oil reservoir 249 from mixing with that contained in the control cylinder (s). of said engine, but allows the oil contained in the lubrication circuit of the variable compression ratio engine or that contained in the oil reservoir 249 to communicate its pressure to that contained in the circuit connected to the control cylinder (s) 8 of said engine.
• the circuit separator 300 comprises at least one sensor 303 for measuring the position of the separator piston.
• FIGS. 7 to 9 show the multistage pressure booster 241 of the hydraulic power station 200 for a variable compression ratio engine.
• the multi-stage pressure booster 241 comprises a multi-stage pressure booster casing 286, a multi-stage piston 281 cooperating on the one hand with at least one emitter cylinder 282 thus constituting a stage, connected either to the engine lubrication circuit of the engine.
• variable compression either to the oil reservoir 249 of the hydraulic unit 200 and secondly with a receiving cylinder 283 hydraulically connected to the pressing cylinders 170 of said engine.
• the multistage pressure booster 241 of the hydraulic power station 200 comprises at least one multi-stage piston drift sensor 284 for measuring the position of the multistage piston 281.
• the multi-stage pressure amplifier 241 comprises as many stage solenoid valves 285 as stages, said stage solenoid valves 285 making it possible to connect each their own stage either with the lubrication circuit of the variable compression ratio engine or with the oil reservoir 249 maintained under pressure by the air reserve 244 of the hydraulic unit 200.
• the stage solenoid valve (s) 285 of the multi-stage pressure amplifier 241 comprises a stage selection valve 287 making it possible to put one or the other of its two inputs in communication with its outlet, the said two inputs that can not be simultaneously communicated with said output.
• stage select spool 287 of stage solenoid valve 285 is actuated in one direction by connecting the first end of said spool with the pressure in the lubrication circuit of said engine and in the other direction by means of a return spring 288 which exerts a force on the second end of said drawer 287.
• the stage solenoid valve (s) 285 of the multistage pressure booster 241 comprises a small solenoid stage selection valve 289 driven by the electromagnetic field produced not simultaneously by two coils, the first coil being used to push said small drawer 289, while the second serves to pull it, said small drawer 289 being held in position when it reaches one or the other end of its stroke by a locking device 315, said small drawer 289 allowing connecting the first end of the stage select spool 287 with either the pressure in the lubrication circuit of said engine or in the open air.
• the stage selection spool 287 cooperates with a discharge valve 290 connecting the emitter cylinder 282 of its own stage with the circuit connected to the oil reservoir 249 of the hydraulic power station 200, said discharge valve 290 allowing the oil to go from said emitter cylinder 282 to said circuit when the pressure in said emitter cylinder 282 exceeds that of said circuit by a certain value.
• FIGS. 10 to 14 show the air pump 256 of the hydraulic power station 200 for a variable compression ratio engine which comprises a piston 258 operating in an air pump cylinder 259 arranged in a housing 272.
• the air pump piston 258 is biased by a return spring 260 and delimits with the air pump cylinder 259 an air chamber 261 on the one hand, and an oil chamber 262 on the other hand.
• the air chamber 261 is located on the opposite side of the return spring 260 and alternatively allows air to be drawn from outside the hydraulic unit 200 and then forced back into the pressurized air reserve. 244.
• the oil chamber 262 is located on the side of the return spring 260 and alternatively allows pressurized oil to be received from the oil pump 254 and then forced back into an oil sump 203 of the engine lubrication rate variable compression by means of the return spring 260 of the air pump piston 258.
• the air pump 256 comprises a yoke 263 which closes the air pump cylinder 259 arranged in the housing 272 on the one hand, and the oil reservoir 249 on the other hand, said cylinder head 263 comprising an intake valve of air 264 and an air outlet valve 265 opening into the oil reservoir 249.
• the air pump 256 comprises a two-position reversing shuttle 266 which allows lifting of its seat 267 or depositing on its seat 267 an inversion ball 268.
• the inversion ball 268 is held on its seat 267 by an inversion spring 276.
• the inversion ball 268 cooperates with a flap 277 which opens into the air pump cylinder 259 to come into contact with the piston 258 of the air pump 256.
• the first position of the reversing shuttle 266 forces the oil from the oil pump 254 to enter the oil chamber 262 (FIGS. 1, 13 and 14), while the second position of the shuttle 262 Inverting 266 allows the oil from the oil pump 254 and that contained in the oil chamber 262 to return to the engine oil sump 203 of the variable compression ratio engine (FIG. 12).
• the reversing shuttle 266 cooperates with a pressure rod 278 at the rear of which the pressure prevailing in the oil chamber 262 is exerted.
• the pressure rod 278 makes it possible to push the shuttle back 266 by its other end so that the oil from the oil pump 254 and that contained in the oil chamber 262 can return to the oil sump 203 engine lubrication variable compression ratio ( Figure 12).
• the reversing shuttle 266 of the air pump 256 is held in one or the other of its extreme positions by a locking device 269.
• the locking device 269 may consist of a locking ball 270 which is pushed by a locking spring 271, held in position in the housing of the air pump 256 by a bore 273 and being housed respectively in two grooves 274, 275 provided on the reversal shuttle 266.
• the air admitted by the air intake valve 264 of the air pump 256 can come either from the inside of the crankcase or engine block 100 of the variable compression ratio engine via or not a device for separating air and oil, or from outside said engine via a conduit known per se.
• the air intake valve 264 of the air pump 256 comprises a large diameter bell 279 which cooperates with an O-ring 280 in order firstly to reduce the pressure difference required to open the said valve, and on the other hand on the other hand, to increase the quantity of air admitted into the tube.
• the air intake valve 264 of the air pump 256 makes it possible to admit into the air chamber 261 air contained in the lubricating oil sump 203 of the variable compression ratio engine via a device permitting to separate the air from the oil.
• FIG. 15 shows the replenishing solenoid valves 243, 246, 257, 314 and the common replenishment ramp 304 of the hydraulic power station 200 for a variable compression ratio engine.
• the common refueling ramp 304 makes it possible to preselect the destination of the oil coming from the high-pressure pump 254, said ramp comprising an inlet and at least one outlet.
• the common refueling ramp 304 comprises as many replenishing solenoid valves as outputs, said solenoid valves having an inlet and an outlet.
• the replenishing solenoid valves 243, 246, 257, 314 of the common replenishment ramp 304 consist of a small replenishing drawer driven by the electromagnetic field that may not be simultaneously produced by two coils, the first coil serving to push said small drawer , while the second serves to pull it, said small replenishing drawer being held in position when it reaches one or the other end of its race by a locking device 315.
• the replenishing solenoid valves 243, 246, 257, 314 of the common refueling ramp 304 each cooperate with at least one non-return valve 306 placed at the outlet of said solenoid valves.
• Each check valve 306 allows the replenishing solenoid valves 243, 246, 257, 314 to supply oil to the circuit located downstream but prevent said oil contained in said circuit from returning to said solenoid valves.
• FIG. 16 shows a selection device 307 for the input pressure of the control cylinders 8 of the hydraulic power station 200 for a variable compression ratio engine.
• the selection device 307 comprises a selection slide 308 for the input pressure of the control jacks 8, said selection slide 308 being in two positions making it possible to put one or the other of its two inputs 309 into communication with one another. his exit 310.
• the first position makes it possible to put into pressure communication the circuit connected to the control cylinder (s) 8 of the engine with the oil tank 249 of the hydraulic unit 200 put under pressure by the air reserve 244.
• the second position makes it possible to put in pressure communication the circuit connected to the control cylinder (s) 8 of the engine with the lubrication circuit of said engine.
• the selection slide 308 of the input pressure of the control cylinders 8 that comprises the selection solenoid valve 311 is actuated in one direction by connecting the first end of said spool with the pressure in the lubrication circuit of said engine and in the other direction by means of a return spring 312 which exerts a force on the second end of said drawer 308.
• the selection solenoid valve 311 comprises a small selection slide 313 moved by the electromagnetic field produced not simultaneously by two coils, the first coil used to push said small drawer 313, while the second serves to pull it, said small drawer 313 being maintained in position when it reaches one or the other end of its stroke by a locking device 315, said small drawer 313 for connecting the first end of the selection valve 308 of the inlet pressure of the control cylinders 8 or with the pressure in the lubrication circuit of said engine, or in the open air.
• FIG. 17 shows the lubricating oil pressure accumulator 240 of the hydraulic power station 200 for a variable compression ratio engine.
• the lubricating oil pressure accumulator 240 makes it possible to damp the pressure variations generated by the operation of the hydraulic unit 200 in the engine lubrication circuit.
• the lubricating oil pressure accumulator 240 consists of an accumulator piston 291 operating in an accumulator cylinder 292 and pressurized against the oil contained in the accumulator cylinder 292 by at least one spring 293.
• the hydraulic unit 200 comprises, in combination with the lubricating oil pressure accumulator 240, an oil outlet unlocking device 294 which prevents the oil from coming out of the oil reservoir 249 when the compression ratio engine variable is stopped.
• the unlocking device 294 for oil outlet consists of an unlocking piston 295 housed in an unlocking cylinder 296 subjected to the lubricating oil pressure of said engine.
• the unlocking piston 295 can push on an unlocking rod 297 in order to lift an unlocking ball 298 from its seat so that the pressure in the oil reservoir 249 can be reflected in the hydraulic circuits connected to the control cylinders 8 on the one hand and the pressing cylinders 170 on the other.
• the accumulator piston 291 of the lubricating oil pressure accumulator 240 and the unlocking piston 295 of the oil output unlocking device 294 are mounted in the same cylinder arranged in the accumulator housing 299.
• the air reserve 244, the oil reserve 249, the lubricating oil pressure accumulator 240, the oil outlet locking device 294 and the circuit separator 300 can all or partly be arranged in the same machined room.
• This same piece may have been previously cast and may have different surfaces on which screw the cylinder head of the air pump 263, the air pump 256, and the multistage amplifier 241. Because of the contact between the air and the oil in the hydraulic unit 200 according to the invention, and to prevent air from accumulating in the control cylinders 8, they may include a degassing device, not shown.
• this degassing device may consist of a groove formed on the control rod of the control cylinders 8, allowing when the compression ratio of the engine is low, to deliberately let the air escape and the oil contained in the upper chamber of the control cylinders 8 through the upper seal of the control rod and to the cylinder block 100 of the engine.
• this degassing device can also be supplemented or replaced by a pressure relief valve not shown, control cylinder 8 which, during the engine temperature rise at variable compression rate, to prevent the expansion of the oil contained in the cylinder (s) control (s) 8 does raise the pressure in said cylinders excessively.
• said relief valve is provided to allow the oil contained in the control jack (s) 8 to escape to the lubricating oil sump 203 of said engine when the pressure prevailing in the chamber said cylinders exceed a certain value.
• valve can advantageously be replaced by a simple nozzle instead of the leakage compensation check valve provided on the actuator (s) 8 of the variable compression ratio engine, said non-return valve having described in earlier patent applications on behalf of the applicant.
• the operation of the hydraulic unit 200 is as follows:
• the air reserve 244 of the hydraulic power unit according to the invention was previously put under pressure, in the workshop, when mounting the variable compression ratio engine.
• the pressure contained in said air reserve 244 is exerted on the oil contained in the oil tank 249 of the hydraulic unit 200.
• the pressure increases in the lubricating oil pressure accumulator 240 and the lubricating oil exerts a force on the unlocking piston 295 of the hydraulic power station 200.
• the unlocking piston 295 then pushes on its release rod 297 and raises the unlocking ball 298 which was hitherto held on its seat by a spring which has the effect of releasing the pressure contained in the oil reservoir 249 and to apply it to the input of the multi-stage pressure amplifier 241 on the one hand, and to the input of the selection slide 308 of the input pressure of the control cylinders 8 on the other hand.
• the hydraulic unit 200 is operative to apply the desired hydraulic pressure to the control cylinders 8 and the pressure cylinders 170 of the variable compression ratio engines.
• variable compression ratio engine requires exerting a high pressure at the input of its control cylinder (s) 8. This pressure is necessary both to increase the stiffness of the oil contained in said control cylinder (s) 8 in order to increase their accuracy in maintaining their nominal position, but also, to avoid any risk of cavitation in the chambers of said cylinders 8, as well as to assist them in moving to increase the compression ratio of the engine at variable compression.
• variable compression ratio engine requires, on the contrary, to apply a lower pressure to the input of the control cylinders 8, said pressure possibly being substantially equal to the pressure prevailing in the lubrication circuit under pressure of said engine.
• the ECU management computer of the engine will order the selector valve 308 of the input pressure of the control cylinders 8 to change position in order to switch its output pressure, which said selection valve 308 performs in communicating the control cylinders 8 either with the oil reservoir 249 of the hydraulic unit 200 pressurized by the air reserve 244, but with the lubrication circuit of said engine.
• the ECU management computer of said engine applies an electrical voltage as appropriate on one or other of the coils of the selection solenoid valve 311, said selection solenoid valve 311 thus constituting the first stage of the control of the selection device
• the hydraulic unit 200 may comprise a circuit separator 300 which integrates a separator piston 301 preventing the oil saturated with air contained in the oil reservoir 249 of said central mixing with that contained in the circuit of the control cylinders 8 of the variable compression ratio engine.
• the oil contained in the oil tank 249 of the hydraulic unit 200 or, as the case may be, that contained in the lubrication circuit of the variable compression ratio engine exerts a pressure on a first face of the separator piston 301, said piston echoing the same and tightly this oil pressure contained in the circuit connected to the control jacks 8 by means of its second face.
• the pressure applied to the pressure cylinders 170 must vary. This is necessary because of the variations of the force applied to the parts of the coupling mobile said engine, which require a greater or lesser effort exerted by the pressure cylinders 170 to limit the acoustic emissions of said engine.
• the different input stages of the multi-stage amplifier 241 - called the emitter cylinders 282 - can be subjected independently. either at the low pressure prevailing in the engine lubrication circuit, or at the high level prevailing in the oil reservoir 249 of the hydraulic unit 200 according to the invention.
• the different input stages of the multi-stage amplifier 241 - said emitter rollers 282 - cooperate to provide the desired pressure for the pressing cylinders 170 by adding up their thrust force, the sum of these forces being applied via the multi-stage piston 281 to a receiver cylinder 283 hydraulically connected to the pressure cylinders 170 of the engine.
• the section of each stage is equal to twice the section of the next stage. According to this strategy and by way of nonlimiting example, if the first stage of a multi-stage amplifier 241 four stages has a section of one cm 2 , the second stage will have a section of two cm 2 , the third of four and the fourth of eight cm 2 .
• the ECU management unit of the variable compression ratio engine wants to apply to the pressing cylinders 170 of said engine any one of the sixteen pressure values, it applies an electrical voltage to one or the other solenoid valve coils 285 which controls the position of the corresponding stage selection drawers 287 which it is necessary that they apply to their stage either a low pressure or a high pressure.
• This has the effect of applying or removing the pressure exerted by the engine lubricating oil at the end of said stage select drawers 287 so that they move to the desired position.
• stage selection drawers 287 each comprise two coils actuating a small spool. 289 stage selection solenoid valve made stable by a locking device 315.
• the first coil assumes the function of pushing said small stage selection solenoid valve spool 289, and the second function of pulling it.
• the small spool 289 connects the end of the stage selection spool 287 with the lubrication pressure of the variable compression ratio engine of so that said drawer 287 is placed and remains in a first position, while in the second position, the small drawer 289 connects the end of the floor selection drawer 287 to the open air.
• stage selection spool 287 is biased by a spring 288 which applies a force on the end of said stage selection spool 287 opposite to that on which the lubrication pressure does or does not apply. function of the position of the small drawer 289.
• the corresponding stage may be closed for a short time, even though the pressing cylinders 170 are subjected to positional variations induced by the operation of the motor. variable compression ratio.
• each stage selection spool 287 cooperates with a discharge valve 290 connecting the chamber of its stage to the circuit connected to the oil reservoir 249 of the hydraulic unit 200 according to the invention.
• This relief valve 290 is designed to open as soon as the pressure of the chamber of the stage to which it is connected becomes greater and too high than that of the oil reservoir 249 of the hydraulic power station 200.
• control cylinders 8 are put into communication with the engine lubrication circuit by the selection slide 308 of the input pressure of the control cylinders 8 and that said control cylinders 8 perform maneuvers. to modify the compression ratio of said engine.
• the lubricating oil pressure accumulator 240 is provided to compensate for said volume variations, and for this reason avoid any sudden drop or rise in the lubrication pressure that is detrimental to the proper lubrication of the engine.
• the hydraulic unit 200 has various sensors 245, 248, 250, 284, 303 which can detect a lack of air or oil resulting from unavoidable leaks occurring in the circuits of said hydraulic plant 200, whether the circuit of the control cylinders 8, and / or the circuit of the pressing cylinders 170.
• These sensors 245, 248, 250, 284, 303 cooperate with a device for replenishing oil and air that integrates the hydraulic unit 200 according to the invention.
• the oil is supplied by a high-pressure oil pump 254 similar or identical to that described in the French patent application FR 2,896,539 belonging to the applicant.
• the oil pump 254 can be driven by any of the camshafts of the variable compression ratio engine and be turned on by a high pressure oil pump solenoid valve 255.
• Air refilling is entrusted to an air pump 256 integrated in the hydraulic unit 200 according to the invention. If the ECU management unit of the variable compression ratio engine detects insufficient pressure in the air supply 244 of the hydraulic unit 200 via an air pressure sensor 245, and taking into account the temperature of the air which is transmitted to said computer by an air temperature sensor 248, the ECU management computer will order the air replenishment of the hydraulic unit 200.
• the operation of the air pump 256 is as follows: the oil from the high pressure oil pump 254 is introduced - via the common refueling ramp 304 - into the oil chamber 262 of the air pump 256 located behind the piston 258 of said air pump, so that said piston will move and compress at low speed the air contained in the air chamber 261 of said air pump 256 located in front of the piston 258 of said air pump 256.
• the inversion shuttle 266 then changes position and its locking device 269 engages to hold it in place in said position.
• the reversing shuttle 266, which until now had allowed the reversal ball 268 to force the oil from the high pressure pump 254 to remain in the oil chamber 262 of the air pump 256, maintains said reversal ball 268 away from its seat 267, which then releases the oil contained in the oil chamber 262 so that it is expelled into the lubricating housing 203 of the variable compression ratio engine by the action of the return spring 260 of the piston 258 of the air pump 256, with the oil from the high pressure pump 254.
• the flap 277 under the action of the return spring 260 of the piston 258 of the air pump 256, is forced to push the reversing shuttle 266 back to its initial position and leaves the reversal ball 268 rest again on his seat 267.
• the locking device 269 of the reversing shuttle 266 again retains said shuttle in a position such that the reversal ball 268 remains firmly seated on its seat 267, while the oil from the high-pressure oil pump 254 is again forced to remain in the oil chamber 262 of the air pump 256, and the air now enclosed in the air chamber 261 of the air pump 256 is gradually compressed to be introduced again in the reserve air 244 of the hydraulic unit 200 according to the invention.
• the hydraulic unit 200 also has other devices enabling it to replenish in oil the different tanks and circuits of said hydraulic unit 200.
• oil reservoir 249 of the hydraulic unit 200 comprises in particular an oil level sensor 250 may consist of a float 252 whose vertical position is measured by means of a position sensor 253.
• said ECU computer will order the replenishment of oil in the oil reservoir 249 of the hydraulic unit 200.
• the ECU management computer will order the activation of the oil reservoir 249 by applying an electrical voltage on one of the coils of the replenishing solenoid valve 314 of the oil reservoir 249 whose replenishing slide is placed on the common refueling ramp 304.
• the hydraulic unit 200 comprises a drift sensor 284 of the multi-stage piston 281 of the multi-stage pressure amplifier 241 may consist of a position sensor capable of measuring the position of said piston of said amplifier.
• the ECU management unit of the variable compression ratio engine detects that, as a result of oil leaks occurring at the pressure ram (s) 170 of the variable compression ratio engine, the position of the piston multi-stage 281 has drifted and exceeds its maximum allowable position, said ECU computer will order the replenishment of oil in the circuit of the pressing cylinders 170 of the hydraulic unit 200 according to the invention.
• the ECU management computer will order the connection of the circuit of the pressure cylinders 170 with that of the high pressure oil pump 254 by applying an electrical voltage on one of the coils of the solenoid valve 243 replenishing the cylinders pressers 170 whose replenishing drawer is placed in the common refueling ramp 304.
• the ECU management computer will order the activation of the high pressure oil pump 254 at the end of the camshaft as described above. These two combined actions will have the effect of restocking the circuit of the presser cylinders 170 via its drawer the corresponding replenishment, said drawer being mounted in series with a check valve 306. This replenishment is maintained by the ECU management computer of the variable compression ratio engine as long as the position of the multi-stage piston 281 is not reached and as the drift sensor 284 of said multi-stage piston 281 does not return to the ECU calculator the desired value.
• the hydraulic unit 200 also comprises a drift sensor 303 of the separator piston 301 of the circuit separator 300 which isolates the circuit connected to the oil reservoir 249 of said central unit, that connected to the (x) cylinder (s) control 8 of the variable compression ratio engine.
• the drift sensor 303 may notably consist of a metal rod 318 integral with the separating piston 301 and introduced into an induction coil, making it possible to measure the position of said separator piston 301 of the circuit separator 300.
• variable compression ratio engine ECU management unit detects that, as a result of oil leaks having occurred at the variable compression ratio engine control cylinder (s), the position of the engine separator piston 301 has drifted and exceeds its maximum allowable position taking into account the position of the control cylinders 8, said computer will order the oil replenishment of the circuit of the control cylinders 8 of said engine.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Lubrication Of Internal Combustion Engines (AREA)

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• 2007
  • 2007-07-19 FR FR0705237A patent/FR2919022B1/fr not_active Expired - Fee Related
• 2008
  • 2008-07-18 KR KR1020107001141A patent/KR20100049544A/ko not_active Withdrawn
  • 2008-07-18 US US12/669,065 patent/US20100206270A1/en not_active Abandoned
  • 2008-07-18 CN CN2008800250851A patent/CN101755112B/zh not_active Expired - Fee Related
  • 2008-07-18 AU AU2008300450A patent/AU2008300450B2/en not_active Ceased
  • 2008-07-18 JP JP2010516540A patent/JP5265677B2/ja not_active Expired - Fee Related
  • 2008-07-18 WO PCT/FR2008/001059 patent/WO2009037395A2/fr not_active Ceased
  • 2008-07-18 CA CA2692703A patent/CA2692703C/fr not_active Expired - Fee Related
  • 2008-07-18 EP EP08832670A patent/EP2179155A2/de not_active Withdrawn

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