CN104929766A - Hydraulic free piston engine - Google Patents
Hydraulic free piston engine Download PDFInfo
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- CN104929766A CN104929766A CN201410106984.1A CN201410106984A CN104929766A CN 104929766 A CN104929766 A CN 104929766A CN 201410106984 A CN201410106984 A CN 201410106984A CN 104929766 A CN104929766 A CN 104929766A
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Abstract
The invention discloses a hydraulic free piston engine. A power piston and a pump piston are in rigid connection through a piston rod to form a piston assembly. The movable piston is disposed in a cylinder, and the pump piston is disposed in a pump. The pump piston is in a differential-pressure stage piston structure, and the pump is provided with hydraulic channels with different diameters. The hydraulic channels are connected with a hydraulic system, and the hydraulic system is a differential-pressure closed type hydraulic system. Through the above technical scheme of the invention, the engine can simplify the structure, reduces the manufacturability of actual manufacturing and machining, and further improving the structural compactness.
Description
Technical field
The present invention relates to power and technical field of hydraulic pressure, particularly relate to a kind of hydraulic free-piston engine.
Background technique
Hydraulic free-piston engine is a kind of dynamic power machine stroke piston combustion engine and pluger type hydraulic pump become one, and the heat energy of fuel combustion is converted into hydraulic energy by reciprocating piston assembly and externally exports by hydraulic free-piston engine.Have that structure is simple, Transmitted chains is short, alterable compression ratio, power transmission adopt the advantages such as flexible media, as the power source of vehicle and other mobile device, the shifter using hydraulic pressure as power source can be particularly useful for.
At present, from the structure type realizing hydraulic free-piston engine principle, there are two kinds of forms: a kind of is that to be connected successively by rigid rod by three pistons such as the power piston of internal-combustion engine, the pump piston of oil hydraulic pump and the compression piston that piston is recovered be the assembly that a piston is elongated; Another kind of mode is for be connected on power piston by pump piston and compression piston, and formation power piston drags 2 or 3 hydraulic pistons as piston assembly.Above-mentioned two kinds of forms all can realize the working principle of hydraulic free-piston engine.One or several hydraulic piston is had to be used to provide energy to the compression stroke of power piston in the scheme of above-mentioned two kinds of hydraulic free-piston engines, because hydraulic free-piston engine saves connecting rod, the compression stroke of power piston for it provides energy, must adopt independent hydraulic system to provide energy for its compression stroke without inertance elements such as flywheels.But, due to the recovery system that will increase power piston all can cause the axial dimension of piston assembly in these two kinds of arrangements excessive (being at least greater than the piston stroke of twice) or pump body portion radial dimension excessive, make hydraulic free-piston engine structure not compact, the technology capability of piston assembly is deteriorated, cylinder block required the shortcomings such as high with the coaxality of corresponding pump piston place cavity volume, has seriously restricted and limited the further application of hydraulic free-piston engine.
Summary of the invention
The object of the invention is to the shortcoming and defect overcoming prior art, a kind of hydraulic free-piston engine is provided, the structure of hydraulic free-piston engine can be simplified, reduce the actual manufacturability manufacturing processing, improve the structural compactness of hydraulic free-piston engine further.
The invention provides a kind of hydraulic free-piston engine, power piston and pump piston are rigidly connected into piston assembly by piston rod, power piston is installed in cylinder block, pump piston is installed in the pump housing, pump piston is differential pressure level piston structure, the pump housing has the hydraulic channel of different-diameter, and described hydraulic channel is connected with hydraulic system, and described hydraulic system is pressure reduction closed hydraulic system.
Preferably, hydraulic system comprises high pressure stage hydraulic circuit and secondary high pressure level hydraulic circuit, and the oil hydraulic circuit of hydraulic system is closed circuit.
Preferably, high pressure stage hydraulic circuit comprises high pressure accumulator further, the first hydraulic channel on the pump housing is connected with high pressure accumulator by the first one-way valve, the second hydraulic channel on the pump housing is connected with high pressure accumulator by the second one-way valve, on the pump housing, the 3rd hydraulic channel is connected with between the second hydraulic channel and the second one-way valve by orifice valve, wherein the first hydraulic channel is fuel-displaced hydraulic channel, second hydraulic channel is fuel-displaced hydraulic channel, 3rd hydraulic channel is damping hole hydraulic channel, the diameter of the first hydraulic channel is greater than the diameter of the second hydraulic channel, the diameter of the second hydraulic channel is greater than the diameter of the 3rd hydraulic channel, first one-way valve and the second one-way valve are all oil outlet one-way valves.
Preferably, secondary high pressure level hydraulic circuit comprises secondary high pressure accumulator further, the 4th hydraulic channel on the pump housing is connected with secondary high pressure accumulator, the 5th hydraulic channel on the pump housing is connected with secondary high pressure accumulator by the 3rd one-way valve, the 6th hydraulic channel on the pump housing is connected with secondary high pressure accumulator by the first solenoid valve, primer fluid press pump is connected with secondary high pressure accumulator by the 4th one-way valve, relief valve is connected with between primer fluid pressure delivery side of pump and the 4th one-way valve, wherein the 5th hydraulic channel is oil-feed hydraulic channel, 6th hydraulic channel is oil-feed solenoid valve passage, the diameter of the 5th hydraulic channel is greater than the diameter of the 6th hydraulic channel, first solenoid valve is FREQUENCY CONTROL solenoid valve, 3rd one-way valve is secondary high pressure in line check valve.
Preferably, the 7th hydraulic channel on the pump housing is connected with the second solenoid valve.
Preferably, the 3rd solenoid valve is connected with between high pressure accumulator and secondary high pressure accumulator.
Preferably, cylinder head is installed on one end of cylinder block, and spark plug is installed in cylinder head, and suction port place is provided with breather check valve, and scavenge space is communicated with scavenging port by scavenging air belt, and relief opening is positioned at the side of cylinder.
Preferably, the breech face of described pump piston is annular acting surface, and end surface is circular acting surface, and the circular acting surface area of end surface is greater than the annular acting surface area of breech face.
Preferably, also comprise controller, controller is connected by circuit with spark plug, the first solenoid valve, the second solenoid valve, the 3rd solenoid valve and relief valve respectively.
Preferably, high pressure accumulator is connected with the oil inlet end of oil hydraulic motor, and secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic motor, and high pressure accumulator is connected with the oil inlet end of oil hydraulic cylinder, and secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic cylinder.
In technical solution of the present invention, energy is provided to the compression stroke of power piston owing to adopting pressure reduction closed hydraulic system, eliminate the piston recovery system in conventional hydraulic free-piston engine, piston assembly only directly drives the pump piston of a differential pressure level piston structure to form by power piston, in conjunction with pressure reduction closed hydraulic system, the work cycle of hydraulic free-piston engine can be completed.Thus greatly simplify the structure of hydraulic free-piston engine, reduce the actual manufacturability manufacturing processing, further increase the structural compactness of hydraulic free-piston engine.
Accompanying drawing explanation
Fig. 1 is hydraulic free-piston engine structural representation in the embodiment of the present invention.
Fig. 2 is the left dead-centre position schematic diagram of hydraulic free-piston engine in the embodiment of the present invention.
Fig. 3 is that in the embodiment of the present invention, hydraulic free-piston engine practices schematic diagram.
Fig. 4 is hydraulic free-piston engine control system schematic diagram in the embodiment of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail.But embodiments of the present invention are not limited thereto.
General hydraulic system low voltage terminal is barometric pressure, or in order to ensure that pump piston does not occur cavitation when oil suction, low voltage terminal pressure brings up to 0.5MPa, and the high pressure oil pressure of output is then the pressure of tens MPas or tens MPas.The basic thought of technical solution of the present invention is improved by the low voltage terminal pressure of hydraulic free-piston engine, and being brought up to by traditional barometric pressure or 0.5MPa pressure is enough to the pressure that driven plunger assembly completes compression stroke, the elevated pressures of such as 5MPa.This pressure is enough to promote the compression stroke that piston assembly completes power piston.And this pressure is brought up to higher pressure when entering expansion stroke under the high-pressure gas pressure effect that fuel combustion produces by piston assembly further, such as the high pressure of 10MPa, and externally export.Adopt the mode improving low voltage terminal pressure, the oil suction task completing pump piston while low voltage terminal pressure-driven piston assembly enters compression stroke can be made full use of.Because low voltage terminal pressure brings up to secondary high pressure (for the high pressure oil of output terminal) by low pressure, the oil-absorbing process of pump piston is become secondary high pressure initiatively oil-feed process.After low voltage terminal pressure is improved, secondary high pressure acts on pump piston and promotes the compression stroke that piston completes power piston, eliminating in conventional hydraulic free-piston engine is the mechanism that the compression stroke of power piston provides piston assembly recovery system of energy etc. huge, enormously simplify the structure of motor and the complexity of system.Meanwhile, processing and the mounting process of part is reduced.
Hydraulic free-piston engine in technical solution of the present invention both shortened Transmitted chains, eliminate again the conversion repeatedly between different motion form, achieve from structure and highly simplify, optimize the Energy Transfer form of motor and transmission system, achieve the soft readjustment of actuating unit.Especially the present invention adopts pressure differential closed hydraulic loop system to provide energy to the compression stroke of power piston, eliminate the piston recovery system in conventional hydraulic free-piston engine, enormously simplify the structure of this motor, piston assembly only directly drives a poor level hydraulic plunger to form by power piston, can complete the work cycle of hydraulic free-piston engine in conjunction with pressure differential Closed Hydraulic closed loop system.Technical solution of the present invention will simplify the structure of hydraulic free-piston engine greatly, reduces the actual manufacturability manufacturing processing, improves the structural compactness of hydraulic free-piston engine.For the further genralrlization application of hydraulic free-piston engine provides good basis.
Fig. 1 is hydraulic free-piston engine structural representation in the embodiment of the present invention.As shown in Figure 1, the power piston 5 of this hydraulic free-piston engine and pump piston 29 are rigidly connected into piston assembly by piston rod 8.Power piston 5 is installed in cylinder block 3, and pump piston 29 is installed in the pump housing 9 by cooperation.
Internal-combustion engine part adopts loop scavenging two stroke engine working principle and structure: cylinder head 2 is installed on one end of cylinder block, displacement and firing chamber is formed with cylinder block and power piston, spark plug 1 is installed in cylinder head, suction port place is provided with breather check valve 7, scavenge space 6 is communicated with scavenging port 33 by scavenging air belt 32, and relief opening 4 is arranged in the side of cylinder.
Pump piston 29 is installed in the pump housing 9, pump piston adopts differential pressure level piston structure, namely the left side (breech face) of pump piston is annular acting surface, and right side (end surface) is circular acting surface, and the circular active area of right side is greater than the annular active area of left side.The pump housing from left to right has the 4th hydraulic channel 31 of different-diameter, the 5th hydraulic channel 28, first hydraulic channel 10, the 6th hydraulic channel 24, second hydraulic channel 11, the 3rd hydraulic channel 15, the 7th hydraulic channel 34, and these hydraulic channels are connected with hydraulic system.
Hydraulic system is pressure reduction closed hydraulic system, and the hydraulic circuit at high pressure accumulator 17 place is high pressure stage hydraulic circuit, and the hydraulic circuit at secondary high pressure accumulator 21 place is secondary high pressure level hydraulic circuit, and whole oil hydraulic circuit is closed circuit.
Wherein the 4th hydraulic channel 31 is directly connected with secondary high pressure accumulator 17, the larger-diameter hydraulic channel of 5th hydraulic channel 28() be connected with secondary high pressure accumulator by the 3rd one-way valve 27, the 6th hydraulic channel 24(small diameter hydraulic channel) be connected with secondary high pressure accumulator by the first solenoid valve 25.Primer fluid press pump 20 is connected with secondary high pressure accumulator by the 4th one-way valve 19, between primer fluid pressure delivery side of pump and the 4th one-way valve, be connected with relief valve 26, for regulating the pressure of primer fluid press pump.Wherein the 5th hydraulic channel is oil-feed hydraulic channel, 6th hydraulic channel is oil-feed solenoid valve passage, the diameter of the 5th hydraulic channel is greater than the diameter of the 6th hydraulic channel, and the first solenoid valve is FREQUENCY CONTROL solenoid valve, and the 3rd one-way valve is secondary high pressure in line check valve.Above-mentioned formation secondary high pressure hydraulic circuit part.
The larger-diameter hydraulic channel of first hydraulic channel 10() be connected with high pressure accumulator 17 by the first one-way valve 12, the hydraulic channel of the second hydraulic channel 11(small diameter) be connected with high pressure accumulator 17 by the second one-way valve 13, the hydraulic channel of the 3rd hydraulic channel 15(minimum diameter) be connected with between the second hydraulic channel 11 and the second one-way valve 13 by orifice valve 14.Wherein the first hydraulic channel is fuel-displaced hydraulic channel, second hydraulic channel is fuel-displaced hydraulic channel, 3rd hydraulic channel is damping hole hydraulic channel, the diameter of the first hydraulic channel is greater than the diameter of the second hydraulic channel, the diameter of the second hydraulic channel is greater than the diameter of the 3rd hydraulic channel, and the first one-way valve and the second one-way valve are all oil outlet one-way valves.High pressure accumulator 17 is arranged in high-pressure and hydraulic oil circuit, for the high pressure liquid pressure energy that stable and storage are exported by hydraulic free-piston engine, is convenient to drive hydraulic actuator.Above-mentioned formation high pressure stage hydraulic circuit part.
7th hydraulic channel 34 is connected with the second solenoid valve 22.
The 3rd solenoid valve 16 is connected with between high pressure accumulator 17 and secondary high pressure accumulator 21.
Fig. 2 is the left dead-centre position schematic diagram of hydraulic free-piston engine in the embodiment of the present invention.Fig. 3 is that in the embodiment of the present invention, hydraulic free-piston engine practices schematic diagram.As shown in Figures 2 and 3, high pressure accumulator is connected with the oil inlet end of oil hydraulic motor 18, secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic motor 18, and high pressure accumulator is connected with the oil inlet end of oil hydraulic cylinder 35, and secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic cylinder 35.
Fig. 4 is hydraulic free-piston engine control system schematic diagram in the embodiment of the present invention.As shown in Figure 4, controller (ECU) is connected by circuit with spark plug, the first solenoid valve, the second solenoid valve, the 3rd solenoid valve and relief valve respectively.
Hydraulic free-piston engine working procedure in the present embodiment is as follows:
When hydraulic free-piston engine starts, primer fluid press pump 20 runs, and by regulation relief valve 26, pressure is adjusted to secondary high pressure stage pressure, as 5MPa, is full of by secondary high pressure accumulator 21.In the process, the second solenoid valve 22 is in open mode, and other solenoid valves are all in closed condition.Secondary high pressure oil in secondary high pressure accumulator is full of secondary high pressure chamber 30 by the 4th hydraulic channel 31, then piston assembly to be shifted onto bottom dead center position as shown in Figure 1 by the left end annulus area of pump piston 29 by piston assembly under the effect of secondary high pressure hydraulic coupling.
Afterwards, close the second solenoid valve 22, close hydrodynamic press pump.First solenoid valve 25 is opened, hydraulic oil then in secondary high pressure accumulator enters pump chamber 23 by the first solenoid valve 25, because the right side circular area of pump piston is much larger than the annulus area of left side, and the pressure of secondary high pressure is enough to overcome the hydraulic coupling that the resistance to compression pression of gas in the jar and pump piston left end ring surface are subject to, move so secondary high pressure hydraulic oil will promote piston assembly to top dead center direction, when pump piston move to open the 5th hydraulic channel 28 time, the first solenoid valve 25 can cut out.Hydraulic oil in secondary high pressure accumulator directly will enter pump chamber by the 3rd one-way valve 27 and the 5th hydraulic channel 28, diameter due to the 5th hydraulic channel 28 is greater than the diameter of the 6th hydraulic channel 24, so, piston will speed up to the motion of top dead center direction, meanwhile, and the gas sealed up for safekeeping in power piston 5 compression cylinder, complete the compression stroke of internal-combustion engine, meanwhile, live gas is being sucked scavenge space 6 in advance by breather check valve 7 by power piston in top dead center movement process, as shown in Figure 2.
When power piston arrives near top dead center, inflammable mixture in spark plug points gas cylinder, the high temperature and high pressure gas that fuel combustion produces promotes piston assembly and moves to lower dead center direction, power piston enters expansion stroke, in the process, pump piston also moves right under the drive of power piston, due to the promotion of pump piston, the instantaneous increase of hydraulic fluid pressure in pump chamber, 3rd one-way valve 27 is closed at once, and the first one-way valve 12 and the second one-way valve 13 will be opened, high pressure liquid force feed in pump chamber is outputted to high voltage terminal moving right in process by pump piston, as 10MPa.When power piston move right open exhaust port 4 time, waste gas after in-cylinder combustion is discharged from exhaust port, when power piston motion is to when opening scavenging port 33, live gas in the precompressed scavenge space 6 in power piston lower end surface enters cylinder by scavenging air belt 32 and scavenging port 33, gas of combustion discharges cylinder further under the promotion of live gas, completes the exchange of waste gas and live gas.
When piston assembly arrives lower dead center, first solenoid valve 25 is again opened and is repeated to enter next circulation, go round and begin again, the hydraulic oil of secondary high pressure is converted into high pressure liquid force feed by reciprocating piston assembly by the heat energy of fuel combustion and exports, realize heat energy to hydraulic pressure transformation of energy.
The mode of control piston assembly operating frequency can be adopted the control of engine output is realized when required power is less.Concrete methods of realizing is: when piston assembly is after completing once circulation, when pump piston moves to the position the 5th hydraulic channel 28 and the first hydraulic channel 10 all cut out, first solenoid valve 25 is still in closed condition, position as shown in Figure 1, due to liquid incompressibility, pump chamber can form instantaneous high pressure, promote piston to the bounce-back of top dead center direction (because liquid is incompressible, rebound amount is very little, pump piston after bounce-back can not open the 5th hydraulic channel 28), and the bounce-back of pump piston causes pump chamber pressure to reduce, piston assembly is pushed back lower dead center act on again the promotion of the left end ring surface of pump piston at secondary high pressure hydraulic oil under by piston assembly again, back piston assembly will stop at lower dead center place several times and so forth.If when now piston assembly still can not stop, piston assembly can continue to move right, until close the second hydraulic channel 11 and the 6th hydraulic channel 24, because now the second solenoid valve 22 is in closed condition, when piston assembly continues to move right, the outflow approach of pump chamber high pressure oil only has by the 3rd hydraulic channel 15, and the damping function of orifice valve 14 will force piston assembly to stop.Until the instruction sending next circulation opened again by the first solenoid valve 25.And the open frequency of the first solenoid valve 25 is exactly the operation frequency of piston assembly, therefore, this motor can realize the control of operation frequency by the unlatching controlling the first solenoid valve 25, and then realizes the control of engine power.
Pump piston 29 of the present embodiment is double-face working pistons, namely front-end face and ear end face are working surface, breech face (left side) is annular working face, and end surface (right side) is ground work profiles, and the circular area of right side is greater than the annulus area of left side.
If when secondary high pressure accumulator 21 causes pressure to reduce due to hydraulic slip in this process, can open the 3rd solenoid valve 16 carry out high pressure supplement, make it be stabilized in operation setup pressure range.
If when motor causes flame-out due to certain uncertain factor in this process, the second solenoid valve 22 can be opened and carries out the adjustment of piston assembly position, reset rapidly.
Pressure differential of the present embodiment refers to the compression stroke adopting secondary high pressure driven plunger assembly to complete power piston, and pump piston exports higher pressure, and engine output depends on the pressure reduction of high pressure and secondary high pressure.
HYDRAULIC CONTROL SYSTEM part realizes the control of hydraulic system jointly by the opening and closing of hydraulic control passage in pump piston movement process and solenoid valve, engine section and oil hydraulic pump part are connected by reciprocating piston assembly, realizes the work of pressure differential formula hydraulic free-piston engine.Specific embodiments is as follows:
1, fundamental composition and working procedure are as previously mentioned.
2, the area of the annular piston of power piston, pump piston, pump piston rear determines the output power of this motor.
3, adopt pressure differential mode to complete the compression stroke of piston, pressure reduction is decided by the annular piston area of power piston, pump piston and pump piston tail end.
The difference of pressure differential formula hydraulic free-piston engine forms of motion needed for load can connect some different hydraulic load.For example need to drive oil hydraulic motor 18 load of rotary motion, need to drive oil hydraulic cylinder 35 load of straight line motion etc. multi-form, wherein rotary motion is as the driving wheel etc. of vehicle, straight line motion as the steering system of vehicle, the reciprocating mechanism, swing mechanism etc. of other running mechanisms.Pressure differential formula hydraulic free-piston engine can provide high pressure liquid pressure energy for above-mentioned hydraulic actuator as hydraulic energy generator, as shown in Figure 3.
This hydraulic free-piston engine is according to vehicle or shifter to the difference of power demand, and this motor exists following state in the course of the work:
1, starting state.Primer fluid press pump 20 runs, and by regulation relief valve 26, pressure is adjusted to secondary high pressure stage pressure, as 5MPa, is full of by secondary high pressure accumulator 21, secondary high pressure oil is full of secondary high pressure chamber 30 by the 4th hydraulic channel 31 simultaneously.In the process, the second solenoid valve 22 is in open mode, and other solenoid valves are all in closed condition.Piston assembly shifted onto bottom dead center position as shown in Figure 1 by the left end annulus area of pump piston 29 under the effect of then piston assembly secondary high pressure hydraulic coupling in secondary high pressure chamber 30, afterwards, close the second solenoid valve 22, close hydrodynamic press pump.First solenoid valve 25 is opened, hydraulic oil then in secondary high pressure accumulator enters pump chamber 23 by the first solenoid valve 25, because the right side circular area of pump piston is much larger than the annulus area of left side, and the pressure of secondary high pressure is enough to overcome the hydraulic coupling that the resistance to compression pression of gas in the jar and pump piston left end ring surface are subject to, move so secondary high pressure hydraulic oil will promote piston assembly to top dead center direction, when pump piston move to open the 5th hydraulic channel 28 time, the first solenoid valve 25 can cut out.Hydraulic oil in secondary high pressure accumulator directly will enter pump chamber by the 3rd one-way valve 27 and the 5th hydraulic channel 28, diameter due to the 5th hydraulic channel 28 is greater than the diameter of the 6th hydraulic channel 24, so, piston will speed up to the motion of top dead center direction, meanwhile, and the gas sealed up for safekeeping in power piston 5 compression cylinder, complete the compression stroke of internal-combustion engine, meanwhile, live gas is being sucked scavenge space 6 in advance by breather check valve 7 by power piston in top dead center movement process, as shown in Figure 2.
When power piston arrives near top dead center, inflammable mixture in spark plug points gas cylinder, the high temperature and high pressure gas that fuel combustion produces promotes piston assembly and moves to lower dead center direction, power piston enters expansion stroke, in the process, pump piston also moves right under the drive of power piston, due to the promotion of pump piston, the instantaneous increase of hydraulic fluid pressure in pump chamber, 3rd one-way valve 27 is closed at once, and the first one-way valve 12 and the second one-way valve 13 will be opened, high pressure liquid force feed in pump chamber is outputted to high voltage terminal moving right in process by pump piston, as 10MPa.When power piston move right open exhaust port 4 time, waste gas after in-cylinder combustion is discharged from exhaust port, when power piston motion is to when opening scavenging port 33, live gas in the precompressed scavenge space 6 in power piston lower end surface enters cylinder by scavenging air belt 32 and scavenging port 33, gas of combustion discharges cylinder further under the promotion of live gas, completes the exchange of waste gas and live gas.When pump piston moves to the position the 5th hydraulic channel 28 and the first hydraulic channel 10 all cut out, position as shown in Figure 1, due to liquid incompressibility, pump chamber can form instantaneous high pressure, promote piston to rebound to top dead center direction, and the bounce-back of pump piston causes pump chamber pressure to reduce, piston assembly is pushed back lower dead center act on again the promotion of the left end ring surface of pump piston at secondary high pressure hydraulic oil under by piston assembly again, and back piston assembly will stop at lower dead center place several times and so forth.If when now piston assembly still can not stop, piston assembly can continue to move right, until close the second hydraulic channel 11, because now the second solenoid valve 22 is in closed condition, when piston assembly continues to move right, the outflow approach of pump chamber high pressure oil only has by the 3rd hydraulic channel 15, and the damping function of orifice valve 14 will force piston assembly to stop.Until the instruction sending next circulation opened again by the first solenoid valve 25.
2, continuous duty.When vehicle or shifter need that hydraulic energy provides at full capacity, this motor first solenoid valve 25 control piston assembly in running, with the continuous to-and-fro motion of natural frequency, realizes maximum capacity and exports high pressure liquid pressure energy.Specific implementation method is: when piston assembly is after completing once circulation, when pump piston arrives lower dead center, the first solenoid valve 25 is just opened, and secondary high pressure enters pump chamber by the first solenoid valve 25, promote piston assembly and at once enter next circulation, and do not stop at lower dead center place.The maximum frequency of operation that this motor can reach is the reciprocating natural frequency of piston assembly, depends on the parameters such as the quality of piston assembly, the gas pressure of fuel combustion and hydraulic coupling.
3, low frequency operation state.When vehicle or shifter even load need less high pressure liquid pressure energy, this motor can ensure that piston assembly works under different operation frequencies under the first solenoid valve 25 state of a control, and then realizes the adjustment of output hydraulic pressure energy.Specific implementation method is: when piston assembly is after completing once circulation, when pump piston moves to the position the 5th hydraulic channel 28 and the first hydraulic channel 10 all cut out, first solenoid valve 25 is still in closed condition, as previously mentioned, when piston assembly will stop at lower dead center under action of hydraulic force, until the instruction sending next circulation opened again by the first solenoid valve 25, piston assembly enters new circulation.The start-up time of the first solenoid valve 25 and the operation frequency of opening time Separation control piston assembly, therefore, can realize the low frequency operation state of this motor by the open frequency controlling the first solenoid valve 25.Low-limit frequency is 0 hertz, and highest frequency is the natural frequency of piston assembly.Frequency range is generally 0 ~ 40Hz.
4, pressure regulates.In engine operation process, when secondary high pressure accumulator 21 causes pressure to reduce due to the pressure loss, pressure can be carried out by control the 3rd solenoid valve 16 to supplement, namely when secondary high pressure accumulator 21 pressure reduces, open the 3rd solenoid valve 16, because the hydraulic fluid pressure in high pressure accumulator 17 is higher than the hydraulic oil in secondary high pressure accumulator 21, therefore, high pressure oil in high pressure accumulator 17 adds in secondary high pressure accumulator 21 by the 3rd solenoid valve 16, the 3rd solenoid valve 16 is closed after making secondary high pressure energy storage pressure be elevated to setting value, ensure that motor normally runs.
5, piston position adjustment.When there is the accidental phenomenons such as incomplete combustion in motor in running; piston assembly can be caused can not to get back to the situation of lower dead center; and then cause the phenomenons such as engine misses shutdown, after there is this phenomenon, need in time piston assembly to be adjusted to lower dead center overline quick starting.Specific implementation method is: opened by control second solenoid valve 22 after controller 36 tests engine misses, pressure oil in pump chamber 23 and fuel tank are connected, be in low-pressure state, the secondary high pressure hydraulic oil of piston assembly in secondary high pressure chamber 30 acts on annular piston face and piston assembly is back into lower dead center, close the second solenoid valve 22, open the first solenoid valve 25 and enter starting state, pilot engine and continue to run.Owing to there being the accumulation of energy effect of high pressure accumulator 17 in system, the short time stops working can not the normal work of influential system.
According to said structure, this motor also can be expanded as diesel engine form.Change spark plug 1 into oil sprayer, fuel changes diesel oil into by gasoline.
Hydraulic free-piston engine in embodiment of the present invention significantly simplify the structure of conventional hydraulic free-piston engine, especially adopt the mode of pressure differential to complete the compression stroke of piston assembly, eliminate the compression system that conventional hydraulic free-piston engine is huge.On the basis that ensure that the advantageous feature of hydraulic free-piston engine, structure greatly simplifies compact.Achieve the soft readjustment of power plant, engine power regulates and adopts mode of frequency regulation, efficiently solves the Economy of conventional engines when low speed and load and is deteriorated, the generation of the rough sledding such as deterioration of emission.The pressure differential formula hydraulic free-piston engine that the present invention relates to achieves alterable compression ratio, can adapt to pluralities of fuel, has effectively widened conventional engines to oil-fired dependence.The piston structure of the pressure differential formula hydraulic free-piston engine that the present invention relates to shortens axial dimension and the radial dimension of motor effectively, makes its more compact structure, improves the processing of its part and assembly process process.
Hydraulic free-piston engine in embodiment of the present invention is applicable to being applied to normal pressure variable-flow, the callable hydraulic system of energy.As the mechanically movings such as engineering machinery, fork truck, crane and municipal tractor and winch etc.Be particularly useful for the power of the shifters such as the robot using hydraulic pressure as power source.As needed can to realize by multiple hydraulic free-piston engine unit combination during relatively high power, in addition, this motor be also applicable to highest speed lower, stopped urban public traffic vehicles frequently, can greatly improve its Economy and power character, effectively can reclaim the energy of frequent braking simultaneously.
Above-described embodiment is the present invention's preferably mode of execution; but embodiments of the present invention are not restricted to the described embodiments; change, the modification done under other any does not deviate from Spirit Essence of the present invention and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (10)
1. a hydraulic free-piston engine, it is characterized in that, power piston and pump piston are rigidly connected into piston assembly by piston rod, power piston is installed in cylinder block, pump piston is installed in the pump housing, and pump piston is differential pressure level piston structure, and the pump housing has the hydraulic channel of different-diameter, described hydraulic channel is connected with hydraulic system, and described hydraulic system is pressure reduction closed hydraulic system.
2. a kind of hydraulic free-piston engine according to claim 1, is characterized in that, hydraulic system comprises high pressure stage hydraulic circuit and secondary high pressure level hydraulic circuit, and the oil hydraulic circuit of hydraulic system is closed circuit.
3. a kind of hydraulic free-piston engine according to claim 2, it is characterized in that, high pressure stage hydraulic circuit comprises high pressure accumulator further, the first hydraulic channel on the pump housing is connected with high pressure accumulator by the first one-way valve, the second hydraulic channel on the pump housing is connected with high pressure accumulator by the second one-way valve, on the pump housing, the 3rd hydraulic channel is connected with between the second hydraulic channel and the second one-way valve by orifice valve, wherein the first hydraulic channel is fuel-displaced hydraulic channel, second hydraulic channel is fuel-displaced hydraulic channel, 3rd hydraulic channel is damping hole hydraulic channel, the diameter of the first hydraulic channel is greater than the diameter of the second hydraulic channel, the diameter of the second hydraulic channel is greater than the diameter of the 3rd hydraulic channel, first one-way valve and the second one-way valve are all oil outlet one-way valves.
4. a kind of hydraulic free-piston engine according to claim 3, it is characterized in that, secondary high pressure level hydraulic circuit comprises secondary high pressure accumulator further, the 4th hydraulic channel on the pump housing is connected with secondary high pressure accumulator, the 5th hydraulic channel on the pump housing is connected with secondary high pressure accumulator by the 3rd one-way valve, the 6th hydraulic channel on the pump housing is connected with secondary high pressure accumulator by the first solenoid valve, primer fluid press pump is connected with secondary high pressure accumulator by the 4th one-way valve, relief valve is connected with between primer fluid pressure delivery side of pump and the 4th one-way valve, wherein the 5th hydraulic channel is oil-feed hydraulic channel, 6th hydraulic channel is oil-feed solenoid valve passage, the diameter of the 5th hydraulic channel is greater than the diameter of the 6th hydraulic channel, first solenoid valve is FREQUENCY CONTROL solenoid valve, 3rd one-way valve is secondary high pressure in line check valve.
5. a kind of hydraulic free-piston engine according to claim 1, is characterized in that, the 7th hydraulic channel on the pump housing is connected with the second solenoid valve.
6. a kind of hydraulic free-piston engine according to claim 4, is characterized in that, is connected with the 3rd solenoid valve between high pressure accumulator and secondary high pressure accumulator.
7. a kind of hydraulic free-piston engine according to claim 1, is characterized in that, cylinder head is installed on one end of cylinder block, spark plug is installed in cylinder head, suction port place is provided with breather check valve, and scavenge space is communicated with scavenging port by scavenging air belt, and relief opening is positioned at the side of cylinder.
8. a kind of hydraulic free-piston engine according to claim 1, is characterized in that, the breech face of described pump piston is annular acting surface, and end surface is circular acting surface, and the circular acting surface area of end surface is greater than the annular acting surface area of breech face.
9. a kind of hydraulic free-piston engine according to claim 1, is characterized in that, also comprise controller, and controller is connected by circuit with spark plug, the first solenoid valve, the second solenoid valve, the 3rd solenoid valve and relief valve respectively.
10. a kind of hydraulic free-piston engine according to claim 1, it is characterized in that, high pressure accumulator is connected with the oil inlet end of oil hydraulic motor, secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic motor, high pressure accumulator is connected with the oil inlet end of oil hydraulic cylinder, and secondary high pressure accumulator is connected with the oil revolving end of oil hydraulic cylinder.
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| CN107100724A (en) * | 2017-06-21 | 2017-08-29 | 天津大学 | Opposed type hydraulic free-piston engine and its driving method |
| CN107100723A (en) * | 2017-06-21 | 2017-08-29 | 天津大学 | Hydraulic free-piston engine energy recycle device and energy reclaiming method |
| CN108167261A (en) * | 2017-11-22 | 2018-06-15 | 上海齐耀动力技术有限公司 | A kind of hydraulic reciprocating driving mechanism and hydraulic reciprocating transfer tube |
| CN108661956A (en) * | 2017-03-28 | 2018-10-16 | 株式会社电装 | hydraulic accumulator and its manufacturing method |
| CN110307189A (en) * | 2019-05-23 | 2019-10-08 | 中国北方车辆研究所 | It is a kind of to provide the component of permanent oil suction pressure for hydraulic pump |
| CN110439671A (en) * | 2019-08-23 | 2019-11-12 | 济南天易迅达电气科技有限公司 | A kind of free-piston engine scavenging structure |
| CN111706560A (en) * | 2020-07-30 | 2020-09-25 | 南京耐摩材料科技有限公司 | Piston type energy accumulator with gas storage cylinder |
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| CN110307189A (en) * | 2019-05-23 | 2019-10-08 | 中国北方车辆研究所 | It is a kind of to provide the component of permanent oil suction pressure for hydraulic pump |
| CN110439671A (en) * | 2019-08-23 | 2019-11-12 | 济南天易迅达电气科技有限公司 | A kind of free-piston engine scavenging structure |
| CN111706560A (en) * | 2020-07-30 | 2020-09-25 | 南京耐摩材料科技有限公司 | Piston type energy accumulator with gas storage cylinder |
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