CN112594372B - Hydraulic system of automobile hybrid power transmission - Google Patents

Abstract

The invention provides a hydraulic system of an automobile hybrid power transmission, and belongs to the technical field of hydraulic pressure. The cold start control method solves the problems of poor cold start performance, high energy consumption and high cost of the existing transmission hydraulic system. The hydraulic system comprises a cooling and lubricating oil path, a high-pressure oil path, a reversing valve, a mechanical lubricating pump and a duplex mechanical pump driven by an engine or a P1 motor, wherein the high-pressure oil path is connected with a clutch piston cavity through a control valve I, the high-pressure oil path is connected with the cooling and lubricating oil path through an overflow valve, the mechanical lubricating pump is driven by the output end of a differential mechanism and is connected with the cooling and lubricating oil path, the duplex mechanical pump comprises a large displacement pump and a small displacement pump, the large displacement pump is respectively communicated with a first oil inlet and the high-pressure oil path of the reversing valve, a left oil outlet and a right oil outlet of the reversing valve are both communicated with the cooling and lubricating oil path, a reversing pilot pressure cavity of the reversing valve is connected with the clutch piston cavity, and the small displacement pump is communicated with the high-pressure oil path. The system has low cost, good cold start performance and low energy consumption.

Description

Hydraulic system of automobile hybrid power transmission

Technical Field

The invention belongs to the technical field of hydraulic pressure, and relates to a hydraulic system of an automobile hybrid power transmission.

Background

A hybrid vehicle is a vehicle in which a vehicle drive system is combined from two or more individual drive systems that can be operated simultaneously, and the vehicle drive power is provided by the individual drive systems individually or jointly depending on the actual vehicle driving state. Generally, the hybrid vehicle is generally referred to as a gasoline-electric hybrid vehicle. The existing hybrid power system of the automobile generally comprises three power assemblies, namely an engine, a generator (P1 motor) and a driving motor (P3 motor).

The hydraulic control system is an important subsystem of various automatic transmissions of hybrid vehicles, and is widely applied to various transmission controls due to high energy density and control stability. The hydraulic system primarily controls the engagement, disengagement and torque transfer of the various clutches and brakes while providing cooling and lubrication flow to the various elements of the transmission. The traditional transmission hydraulic system has high energy consumption due to oil supply by a single pump, and the advantages of the traditional transmission hydraulic system cannot be embodied in a new energy hybrid power transmission taking energy conservation and emission reduction as important design targets, so that a new hydraulic system design is required to meet the requirements of the new energy transmission on energy consumption and emission control.

At present, oil supply schemes of a mechanical pump and an electronic pump or an electronic duplex pump are mostly adopted in a hydraulic system of an automobile hybrid transmission on the market, the mechanical pump is driven by an engine, and the electronic pump is driven by an oil pump motor, for example, a hydraulic control system of a double-clutch transmission disclosed in Chinese patent application (application number: 201610218071.8). Also for example, the chinese patent application (application No.: 201810453555.X) discloses an automatic transmission flow active control system based on a dual-pump source variable control technology.

The conventional transmission hydraulic system can better reduce the discharge capacity of the mechanical pump through auxiliary oil supply of the electronic pump, further reduce the overflow loss of the hydraulic system, and meet the requirement of the transmission hydraulic system on oil supply of the oil pump under the high-speed and low-speed working conditions of a vehicle. However, the cost of using the electronic pump is high, and the mechanical efficiency of the electronic pump is low due to high oil viscosity in a low-temperature environment, so that the cold start characteristic is poor; and the electronic pump directly supplies oil to the clutch control loop, and due to the existence of the oil pump motor, the electronic pump has lower total efficiency, unobvious energy-saving effect under the working condition of high-speed cruising, high energy consumption and high cost.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a hydraulic system of an automobile hybrid power transmission, which aims to solve the technical problems that: how to solve the problem that the existing hydraulic system has poor cold starting performance and high energy consumption and cost.

The purpose of the invention can be realized by the following technical scheme: a hydraulic system of an automobile hybrid power transmission comprises a cooling and lubricating oil path and a high-pressure oil path, wherein the high-pressure oil path and a clutch piston cavity are controlled to be on and off through a control valve I, the high-pressure oil path is communicated with the cooling and lubricating oil path through an overflow valve, and the hydraulic system is characterized by further comprising a reversing valve with an oil inlet I, a left oil outlet and a right oil outlet, a mechanical lubricating pump driven by the output end of a differential mechanism and a duplex mechanical pump driven by an engine or a P1 motor, wherein the mechanical lubricating pump is connected with the cooling and lubricating oil path, the duplex mechanical pump comprises a large displacement pump and a small displacement pump, the large displacement pump is communicated with the oil inlet I, the left oil outlet and the right oil outlet are both communicated with the cooling and lubricating oil path, a reversing pilot pressure cavity of the reversing valve is communicated with the clutch piston cavity, and the small displacement pump is communicated with the high-pressure oil path, the large displacement pump is communicated with the high-pressure oil way.

In the hydraulic system, oil supply of the system consists of a mechanical lubrication pump driven by the output end of a differential and a duplex mechanical pump driven by an engine or a P1 motor. The mechanical lubrication pump provides cooling and lubricating flow for the system, and the flow is positively correlated with the vehicle speed, so that the requirement on the cooling flow when the driving motor is driven at different rotating speeds in the pure electric mode of the hybrid power transmission is met. The duplex mechanical pump is driven by a P1 motor or an engine, so that the quick response of the system pressure during the cold start of the hydraulic system under the low-temperature working condition is ensured, the problems that the cold start system is slow in response due to insufficient power of an oil pump motor and large viscosity of low-temperature oil in the conventional electronic pump oil supply system are solved, and the cold start performance is improved. Preferably, a first throttling hole is formed between the left oil outlet and the cooling and lubricating oil path (the first throttling hole can be eliminated and is flexibly configured according to the flow demand of the system). The duplex mechanical pump is formed by combining a large-displacement pump and a small-displacement pump, when the clutch needs to be quickly combined, a control valve I controls a clutch piston cavity to be communicated with a high-pressure oil way, the pressure of a high-pressure loop can be instantly reduced, an overflow port of an overflow valve is closed, a reversing valve works at the left position, and due to the design of a throttling hole I (when the throttling hole is not arranged, the channel is not communicated), the large-displacement pump and the small-displacement pump simultaneously supply oil to the clutch piston cavity of the clutch through the high-pressure oil way, so that the requirement of quick response of a system is met. After the clutch is combined, the pressure of the oil way is increased to a certain value, the reversing valve is switched to the right position to work, the large displacement pump is switched to supply oil for cooling and lubricating the system, the small displacement pump continues to supply oil for passing through the high-pressure oil way to maintain the pressure of the system, and on the premise of meeting the control pressure requirement and the response requirement of the system, the overflow loss of the system is greatly reduced, and the energy consumption is reduced.

In the hydraulic system of the automobile hybrid power transmission, the reversing valve is a hydraulic control reversing valve, and can realize automatic control reversing according to the pressure change of the clutch piston cavity. The clutch is not engaged when the vehicle is in series mode and the extra flow demand caused by the power generated by the P1 motor is provided by the dual mechanical pump. At the moment, the hydraulic control reversing valve is switched to a left position to work, the large displacement pump provides lubricating and cooling flow for the system through a left position oil outlet or an overflow valve core (when the left position has no throttling hole), the small displacement pump provides lubricating and cooling flow for the system through an overflow port of the overflow valve, only the small displacement pump flows through the overflow valve core, and the overflow pressure is the pressure caused by the spring force of the overflow valve core, so the overflow loss is small. When a vehicle enters an engine direct-drive mode, a transmission controller sends a clutch combination signal, a first control valve controls a clutch piston cavity to be communicated with a high-pressure oil way, the pressure of the high-pressure oil way can be instantly reduced, an overflow valve pushes an overflow valve core to close an overflow port under the action of spring force, at the moment, the left position of a hydraulic control reversing valve works, as the vehicle speed is high at the moment, the rotating speed of a duplex mechanical pump is high, the flow rate is large, and the flow rate of a large-displacement pump enters the high-pressure oil way to be converged with a small-displacement pump to pre-charge the clutch piston cavity under the throttling action of a first throttling hole at an outlet of the duplex mechanical pump, so that the requirement of rapid response of the clutch pressure on large flow rate is met; when the clutch piston cavity is pre-charged and the pressure of the high-pressure oil way is increased to a certain value, the reversing valve core of the hydraulic control reversing valve is switched to the right position to work under the action of the pressure, the large displacement pump supplies oil to the cooling and lubricating oil way through the right position oil outlet, and the small displacement pump supplies oil to the high-pressure oil way.

In the hydraulic system of the automobile hybrid power transmission, the large displacement pump is communicated with the high-pressure oil way through the first check valve. The design of the one-way valve I can prevent oil in the high-pressure oil way from flowing back to the large-displacement pump, and the oil pressure of the high-pressure oil way is guaranteed.

In the hydraulic system of the hybrid transmission of the automobile, the first control valve is an electromagnetic proportional pressure control valve. When the pressure of the clutch piston cavity is increased to a certain value after the pre-charging, the hydraulic control reversing valve is switched to the right position to work under the action of the pressure of the clutch piston cavity, the large displacement pump supplies oil to the cooling and lubricating oil way, and the small displacement pump supplies oil to the high pressure oil way. The pressure required by the clutch is determined by the control current of the electromagnetic proportional valve, the pressure of the clutch piston cavity acts on the relief valve spool spring cavity as pilot control pressure, so that the sum of the pressure of the high-pressure oil way and the pressure caused by the pressure of the clutch piston cavity and the spring force of the relief valve spool can meet the pressure required by the clutch for transmitting torque without causing extra loss, and the control logic is simple, low in cost and easy to debug.

In the hydraulic system of the automobile hybrid transmission, the cooling and lubricating oil path comprises a clutch cooling branch communicated with a cooling cavity of the clutch, and the clutch cooling branch is provided with a second orifice. Through the design of the second throttling hole, when the automobile is in a series mode, the requirement of the lubricating flow of the clutch is met by the flow of the second throttling hole, and extra clutch dragging loss caused by overhigh flow is avoided.

In the hydraulic system of the automobile hybrid power transmission, the hydraulic system further comprises a flow control valve, a control valve core of the flow control valve divides an inner cavity of the flow control valve into a second spring cavity located at the left end and a second reversing pilot pressure cavity located at the right end, the flow control valve is further provided with a second oil inlet and a second oil outlet, the second oil outlet is connected with a clutch cooling branch located at one side of the second throttling hole close to a cooling cavity of the clutch, the second oil inlet is connected with a clutch cooling branch located at the other side of the second throttling hole, and a second spring abutting against the control valve core is arranged in the second spring cavity. When the automobile is in a series mode, a control valve core of the flow control valve is in left-side working under the action of elastic force of the second spring, an oil outlet is in a closed state, the requirement for lubrication flow of the clutch is met by the flow of the second throttling hole, and extra clutch dragging loss caused by overhigh flow is avoided. In the clutch combination process, the pressure of a clutch piston cavity is gradually increased, the flow control valve enables the control valve core to move leftwards to a middle position to work by overcoming the elastic force of the spring II under the action of the pressure of the clutch piston cavity, the oil outlet is opened and communicated with the oil inlet II, lubricating oil enters a clutch cooling branch through the oil outlet of the flow control valve to cool the clutch, and the temperature rise caused by clutch combination sliding friction is reduced. After the clutch is combined, the control pressure is increased, the control valve core continuously moves leftwards to work to the right position, the oil outlet is closed, and the cooling flow of the clutch is reduced to avoid the increase of the dragging torque.

In the hydraulic system of the automobile hybrid power transmission, a first safety valve and a first pressure sensor are further arranged on the high-pressure oil path. The first pressure sensor can detect the pressure of the high-pressure oil way, and when the pressure of the high-pressure oil way exceeds a specified value, oil can be discharged outwards through the first safety valve, so that a protection effect is achieved on the system.

In the hydraulic system of the automobile hybrid power transmission, a high-pressure filter is further arranged on the high-pressure oil path. The high-pressure filter ensures the cleanliness of oil in the high-pressure loop and ensures the normal operation of a high-pressure control system.

In the hydraulic system of the automobile hybrid power transmission, the small displacement pump is communicated with the high-pressure oil passage through the check valve II. The design of the check valve II can prevent oil in the high-pressure oil way from flowing back to the small displacement pump, and the oil pressure of the high-pressure oil way is ensured.

In the hydraulic system of the automobile hybrid transmission, the cooling and lubricating oil path further comprises a motor cooling branch and a shaft cooling branch, and the motor cooling branch and the shaft cooling branch are respectively provided with a third orifice and a fourth orifice. Preferably, an oil cooler is further arranged on the motor cooling branch.

In the hydraulic system of the automobile hybrid power transmission, the motor cooling branch comprises a first branch for cooling the P1 motor and a second branch for cooling the P3 motor, and the first branch and the second branch respectively comprise a fifth orifice and a sixth orifice. The cooling and lubricating flow requirements of the P1 motor and the P3 motor are respectively met by the five throttle holes and the six throttle holes, unnecessary loss caused by overlarge flow is avoided, and energy consumption is reduced.

In the hydraulic system of the automobile hybrid power transmission, a second safety valve is further arranged on the cooling lubricating oil pipeline. And the second safety valve is used for limiting the highest pressure of the cooling lubricating oil path.

In the hydraulic system of the automobile hybrid power transmission, one end of the electromagnetic proportional valve is connected with the high-pressure oil way, the other end of the electromagnetic proportional valve is connected with a clutch piston cavity of the clutch through a control loop, and the overflow valve and the flow control valve are both connected with the control loop.

In the hydraulic system of the automobile hybrid power transmission, the control circuit is also provided with a spring accumulator and a second pressure sensor. The spring accumulator is used for stabilizing the pressure of the clutch piston cavity, and the pressure sensor II is used for detecting the pressure of the clutch piston cavity.

Compared with the prior art, the hydraulic system of the automobile hybrid power transmission has the following advantages:

1. the oil supply of the whole hydraulic system consists of a mechanical lubrication pump driven by the output end of the differential and a duplex mechanical pump driven by an engine or a P1 motor, and compared with the existing oil supply system of an electronic pump, the oil supply system has low cost and high total efficiency.

2. The duplex mechanical pump is driven by a P1 motor or an engine, so that the quick response of the system pressure during the cold start of the hydraulic system under the low-temperature working condition is ensured, the problem of slow system response during the cold start caused by insufficient power of an oil pump motor and large viscosity of oil in the conventional electronic pump oil supply system is solved, and the cold start performance of the hydraulic system is improved.

3. A duplex mechanical pump is adopted to supply oil to a high-pressure oil way, the clutch is combined with a double pump in a pre-oil-filling stage to fill oil to the clutch simultaneously to meet the requirement of high flow rate of quick response, the clutch is switched to a small-displacement pump after being combined to supply oil to the high-pressure oil way to maintain the pressure of the system, and the overflow loss of the system is greatly reduced on the premise of meeting the requirement of the control pressure and the response of the system.

4. The clutch lubrication cooling flow control is composed of a second throttling hole and a flow control valve, and when the clutch is not combined, the lubrication cooling flow is only provided by the second throttling hole, so that the lubrication requirement is met; when the clutch is combined, the middle position of the control valve core works, and the lubricating and cooling flow of the clutch is simultaneously provided by the second throttling hole and the flow control valve, so that the requirements of sliding friction, heating, cooling and lubricating of the clutch are met; after the clutch is combined, the control valve core is closed, and the lubricating flow is only provided by the throttle orifice two flow, so that the requirement of cooling and lubricating large flow when the clutch is combined is ensured, and the dragging torque caused by the cooling and lubricating flow when the clutch is not combined is reduced.

5. The pressure of a piston cavity of the clutch and the pressure of the system are simultaneously controlled by the electromagnetic proportional valve and the overflow valve, the control logic of system software is simple, the cost is low, the debugging is easy, the requirement of controlling the pressure of the clutch is met, extra overflow loss cannot be brought, and the control difficulty of a hydraulic system is reduced.

Drawings

FIG. 1 is a control schematic diagram of the hydraulic system of the present automotive hybrid transmission.

Fig. 2 is a block diagram of the reversing valve in left-hand operation.

Figure 3 is a block diagram of the reversing valve in the right position of operation.

Fig. 4 is a structural view of the flow control valve in the left position of operation.

Fig. 5 is a structural view of the flow control valve in the neutral operation.

Fig. 6 is a structural view of the flow control valve in the right position operation.

In the figure, 1, cooling and lubricating oil path; 1a, a clutch cooling branch; 1b, a motor cooling branch; 1b1, branch one; 1b2, branch two; 1c, a shaft cooling branch; 2. a high-pressure oil path; 3. a clutch; 3a, a clutch piston cavity; 3b, a cooling cavity; 4. a first control valve; 5. an overflow valve; 6. a diverter valve; 6a, a first oil inlet; 6b, a left oil outlet; 6c, a right oil outlet; 6d, a first spring cavity; 6e, a first reversing pilot pressure cavity; 6f, a first spring; 6g, a reversing valve core; 7. a mechanical lubrication pump; 8. a duplex mechanical pump; 8a, a large displacement pump; 8b, a small displacement pump; 9. a first orifice; 10. a one-way valve I; 11. a second orifice; 12. a flow control valve; 12a, a control valve core; 12b and a second spring cavity; 12c, a second reversing pilot pressure cavity; 12d, a second oil inlet; 12e, an oil outlet; 12f, a second spring; 13. a first safety valve; 14. a first pressure sensor; 15. a high pressure filter; 16. a second one-way valve; 17. a third orifice; 18. a fourth orifice; 19. a fifth orifice; 20. a sixth orifice; 21. a second safety valve; 22. a control loop; 23. a spring accumulator; 24. a second pressure sensor; 25. a throttle hole seventh; 26. an oil pan; 27. a one-way valve III; 28. and a third pressure sensor.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

The automobile hybrid power system comprises an engine, a generator (P1 motor), a driving motor (P3 motor) and other three power assemblies. As shown in FIG. 1, the hydraulic system of the automobile hybrid power transmission comprises a cooling lubricating oil path 1, a high-pressure oil path 2, a control circuit 22, a reversing valve 6, a flow control valve 12, a mechanical lubricating pump 7 driven by the output end of a differential, and a duplex mechanical pump 8 driven by an engine or a P1 motor. The high-pressure oil path 2 is connected with a clutch piston cavity 3a of the clutch 3 through a control loop 22, a control valve I4 is arranged at the connection position of the high-pressure oil path and the clutch piston cavity for controlling on-off, and the control valve I4 is an electromagnetic proportional valve.

Specifically, the mechanical lubrication pump 7 is connected to the oil pan 26 and the cooling lubrication oil passage 1, respectively. The cooling and lubricating oil circuit 1 is also provided with a third check valve 27 which can prevent oil from flowing back to the oil pan 26 through the mechanical lubricating pump 7, and the cooling and lubricating oil circuit 1 is also provided with a third pressure sensor 28 and a second safety valve 21.

The reversing valve 6 is a hydraulic control reversing valve, a first oil inlet 6a, a left oil outlet 6b and a right oil outlet 6c are arranged on the reversing valve 6, a reversing valve core 6g in the reversing valve 6 divides a valve cavity of the reversing valve 6 into a first spring cavity 6d located on the left side and a first reversing pilot pressure cavity 6e located on the right side, a first spring 6f is arranged in the first spring cavity 6d, the reversing valve core 6g always has the tendency of communicating the left oil outlet 6b with the first oil inlet 6a under the left working condition under the action of the first spring 6f, the first reversing pilot pressure cavity 6e is communicated with the high-pressure oil way 2, and the reversing valve 6 is switched to work in the right position when the pressure of the clutch piston cavity 3a is increased. The left oil outlet 6b and the right oil outlet 6c are communicated with the cooling and lubricating oil circuit 1, a first throttling hole 9 is formed between the left oil outlet 6b and the cooling and lubricating oil circuit 1, and a fourth check valve is arranged at the communication position of the left oil outlet 6b and the right oil outlet 6c and the cooling and lubricating oil circuit 1.

The duplex mechanical pump 8 includes a large displacement pump 8a and a small displacement pump 8b, and both the large displacement pump 8a and the small displacement pump 8b are connected to the oil pan 26. And the large-displacement pump 8a is communicated with the first oil inlet 6a, and the large-displacement pump 8a is also communicated with the high-pressure oil path 2 through a first check valve 10. The small displacement pump 8b is communicated with the high-pressure oil path 2 through a second one-way valve 16, and the high-pressure oil path 2 is also provided with a high-pressure filter 15, a first safety valve 13 and a first pressure sensor 14.

And a safety valve II 21 is further arranged on the cooling and lubricating oil path 1, and the cooling and lubricating oil path 1 comprises a motor cooling branch 1b, a shaft cooling branch 1c and a clutch cooling branch 1a communicated with a cooling cavity 3b of the clutch 3. The clutch cooling branch 1a has a second orifice 11, and the motor cooling branch 1b and the shaft cooling branch 1c have a third orifice 17 and a fourth orifice 18, respectively. The motor cooling branch 1b is also provided with an oil cooler, the motor cooling branch 1b is provided with a first branch 1b1 for cooling the P1 motor and a second branch 1b2 for cooling the P3 motor, and the first branch 1b1 and the second branch 1b2 are respectively provided with a fifth throttle hole 19 and a sixth throttle hole 20.

The control circuit 22 is also provided with a spring accumulator 23 and a second pressure sensor 24. The control valve core 12a of the flow control valve 12 divides the inner cavity of the flow control valve 12 into a spring cavity two 12b at the left end and a reversing pilot pressure cavity two 12c at the right end, the flow control valve 12 is further provided with an oil inlet two 12d and an oil outlet 12e, the oil outlet 12e is connected with a clutch cooling branch 1a at one side of the throttle hole two 11 close to the cooling cavity 3b of the clutch 3, the oil inlet two 12d is connected with the clutch cooling branch 1a at the other side of the throttle hole two 11, and a spring two 12f which is pressed against the control valve core 12a is arranged in the spring cavity two 12 b. An orifice seven 25 is also provided in the control circuit 22.

The high-pressure oil way 2 is communicated with the cooling and lubricating oil way 1 through an overflow valve 5, the overflow valve 5 is a mechanical valve, an overflow valve core of the overflow valve 5 divides a valve cavity of the overflow valve 5 into a third pressure cavity on the left side and a third spring cavity on the right side, the third pressure cavity is communicated with the high-pressure oil way 2, the third spring cavity is communicated with the control loop 22, the third spring cavity is internally provided with a third spring, and an overflow port of the overflow valve 5 is communicated with the cooling and lubricating oil way 1.

The working principle of the system is as follows:

when the service clutch 3 is disengaged, i.e., the hybrid transmission is operating in an electric-only/series mode, the vehicle is driven by the P3 motor, and the P1 motor is in a shutdown or generating mode.

Under pure electric operating mode, the cooling lubrication flow of motor is provided by mechanical lubrication pump 7, and its flow is positive correlation with the speed of a motor, can make its flow just with P3 motor during operation cooling lubrication flow demand phase-match through the discharge capacity and the driving speed of reasonable selection mechanical lubrication pump 7.

In a series mode, an extra flow demand caused by power generation of a P1 motor is provided by a duplex mechanical pump 8, at the moment, the electromagnetic proportional valve is in a closed state when power is lost, a reversing valve core 6g of the reversing valve 6 is in a left position to work, a first oil inlet 6a of the reversing valve 6 is communicated with a left oil outlet 6b, a right oil outlet 6c is closed (as shown in fig. 2), an overflow port of an overflow valve 5 is in an open state, a large displacement pump 8a provides flow for a cooling lubricating oil path 1 through the left oil outlet 6b, a small displacement pump 8b provides flow for the cooling lubricating oil path 1 through the overflow port of the overflow valve 5, only the flow of the small displacement pump 8b passes through the overflow valve core, and the overflow pressure is pressure caused by the spring force of the overflow valve 5, so that the overflow loss is small. In addition, under the working condition, the flow control valve 12 is in a left-position working state, the control valve core 12a closes the oil outlet 12e under the action of the second spring 12f (as shown in fig. 4), the lubrication flow demand of the clutch 3 is met by the flow of the second throttle hole 11, and extra dragging loss of the clutch 3 caused by overhigh flow is avoided.

When a vehicle meets the condition that the hybrid power transmission enters an engine direct-drive mode, a transmission controller sends a clutch 3 combination signal, an electromagnetic proportional valve is electrified, a clutch piston cavity 3a is communicated with a high-pressure oil way 2, the pressure of the high-pressure oil way 2 can be instantly reduced, an overflow port of an overflow valve 5 is closed under the action of a spring force, a reversing valve core 6g of a reversing valve 6 is in left-position work under the action of a spring 6f, an oil inlet one 6a of the reversing valve 6 is communicated with an oil outlet 6b in the left position, and an oil outlet 6c in the right position is closed. At the moment, the vehicle speed is high, the rotating speed of the duplex pump is high, the flow rate is high, due to the throttling effect of the first throttling hole 9 at the left oil outlet 6b, the flow rate of the large displacement pump 8a enters the high-pressure oil way 2 through the first one-way valve 10, is converged with the small displacement pump 8b, and is pre-filled in the clutch piston cavity 3a of the clutch 3 through the control circuit 22, and the requirement of the clutch 3 for quick pressure response to the high flow rate is met.

In the process of combining the clutch 3, the pressure of the clutch piston cavity 3a gradually rises, the control valve spool 12a of the flow control valve 12 is moved to the middle position to work against the elastic force of the second spring 12f under the action of the right pilot pressure (the pressure of the clutch piston cavity 3a), the oil outlet 12e is opened to be communicated with the second oil inlet 12d, lubricating oil enters the clutch cooling branch 1a through the oil outlet 12e of the flow control valve 12 to cool the clutch 3, and the temperature rise caused by the combination sliding friction of the clutch 3 is reduced, as shown in fig. 5.

When the clutch piston cavity 3a is pre-filled and the pressure rises to a certain value, the reversing valve core 6g of the reversing valve 6 is shifted to the right position to work against the elastic force of the spring I6 f under the pressure action of the high-pressure oil way 2, the left oil outlet 6b is closed, the right oil outlet 6c is communicated with the oil inlet I6 a (as shown in figure 3), the large displacement pump 8a supplies oil to the cooling and lubricating oil way 1, the small displacement pump 8b supplies oil to the high-pressure oil way 2, the clutch 3 is combined because the clutch piston cavity 3a is filled with oil and the friction plates are compressed by the piston at the moment, the pressure building flow demand of the clutch piston cavity 3a is only the flow caused by the compression deformation of the friction plates and the leakage of the system, and the flow of the small flow pump can completely meet the demand. The control valve core 12a of the flow control valve 12 continuously moves to the left to work to the right position against the elastic force of the second spring 12f under the action of the right pilot pressure (the pressure of the clutch piston cavity 3a), the oil outlet 12e is closed, and the cooling flow of the clutch 3 is reduced to avoid the increase of the dragging torque, as shown in fig. 6.

When the clutch 3 is engaged, the vehicle enters engine direct drive mode. The hybrid power transmission controller controls the input current of the electromagnetic proportional valve, so that the pressure of the clutch piston cavity 3a is the real-time pressure corresponding to the torque required by the vehicle to run. Meanwhile, under the action of the overflow valve 5, the pressure of a system high-pressure loop is always higher than the real-time pressure of the clutch 3 by the pressure caused by the spring force of the overflow valve 5, the reversing valve 6 works at the right position, so that the large-displacement pump 8a supplies oil to the cooling lubricating oil circuit 1, the outlet pressure is only lubricating pressure, the small-displacement pump 8b supplies oil to the high-pressure oil circuit 2 to maintain the pressure of a clutch piston cavity 3a required by vehicle running, and the system overflow loss is only the overflow loss caused by the small-displacement pump 8b, so that the overflow loss of the high-pressure loop after the clutch 3 is combined is greatly reduced, the efficiency of a hydraulic system is improved, and the power consumption of the system is reduced.

The oil supply of the hydraulic system consists of a mechanical lubricating pump 7 driven by the output end of the differential mechanism and a duplex mechanical pump 8 driven by an engine or a P1 motor, compared with the existing oil supply system of an electronic pump, the oil supply system has low cost, and ensures the quick response of the system pressure when the hydraulic system is in cold start under the low-temperature working condition, solves the problem of slow response of the system when the hydraulic system is in cold start due to insufficient power of the oil pump motor and large viscosity of oil, and improves the performance of cold start. The clutch 3 is combined with the pre-charging stage double pumps to charge the clutch 3 simultaneously to meet the large flow demand of quick response, the clutch 3 is switched to the small displacement pump 8b to supply oil to the high-pressure oil circuit 2 to maintain the system pressure after being combined, on the premise of meeting the system control pressure demand and the response demand, the overflow loss of the system is greatly reduced, and the design of lubricating and cooling flow control of the clutch 3 is adopted, so that the large flow demand of cooling and lubricating of the clutch 3 during combination is ensured, the dragging torque caused by the cooling and lubricating flow is reduced when the clutch is not combined, and the energy consumption is reduced.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although the cooling and lubricating oil path 1, the clutch cooling branch 1a, the motor cooling branch 1b, the first branch 1b1, the second branch 1b2, the shaft cooling branch 1c, the high-pressure oil path 2, the clutch 3, the clutch piston chamber 3a, the cooling chamber 3b, the first control valve 4, the overflow valve 5, the reversing valve 6, the first oil inlet 6a, the left oil outlet 6b, the right oil outlet 6c, the first spring chamber 6d, the first reversing pilot pressure chamber 6e, the first spring 6f, the reversing valve core 6g, the mechanical lubricating pump 7, the duplex mechanical pump 8, the large displacement pump 8a, the small displacement pump 8b, the first orifice 9, the first check valve 10, the second orifice 11, the flow control valve 12, the control valve core 12a, the second spring chamber 12b, the second reversing pilot pressure chamber 12c, the second oil inlet 12d, the oil outlet 12e, the second spring 12f, the first safety valve 13, the first pressure sensor 14, High pressure filter 15, check valve two 16, orifice three 17, orifice four 18, orifice five 19, orifice six 20, relief valve two 21, control circuit 22, spring accumulator 23, pressure sensor two 24, orifice seven 25, oil pan 26, check valve three 27, pressure sensor three 28, etc., but does not exclude the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

Claims (10)

1. A hydraulic system of an automobile hybrid power transmission comprises a cooling and lubricating oil way (1) and a high-pressure oil way (2), wherein the high-pressure oil way (2) and a clutch piston cavity (3a) are controlled to be switched on and off through a control valve I (4), and the high-pressure oil way (2) is communicated with the cooling and lubricating oil way (1) through an overflow valve (5), and the hydraulic system is characterized by further comprising a reversing valve (6) with a first oil inlet I (6a), a left oil outlet (6b) and a right oil outlet (6c), a mechanical lubricating pump (7) driven by an output end of a differential mechanism, and a duplex mechanical pump (8) driven by an engine or a P1 motor, wherein the mechanical lubricating pump (7) is connected with the cooling and lubricating oil way (1), the duplex mechanical pump (8) comprises a large displacement pump (8a) and a small displacement pump (8b), and the large displacement pump (8a) is communicated with the first oil inlet (6a), the left oil outlet (6b) and the right oil outlet (6c) are communicated with the cooling and lubricating oil path (1), the reversing pilot pressure chamber (6e) of the reversing valve (6) is communicated with the clutch piston chamber (3a), the small displacement pump (8b) is communicated with the high-pressure oil path (2), and the large displacement pump (8a) is communicated with the high-pressure oil path (2).

2. The automotive hybrid transmission hydraulic system according to claim 1, characterized in that the directional control valve (6) is a pilot operated directional control valve.

3. The hydraulic system of the automobile hybrid transmission according to claim 1, characterized in that the large displacement pump (8a) is communicated with the high-pressure oil passage (2) through a one-way valve I (10).

4. The hydraulic system of a hybrid transmission for a vehicle according to claim 1, 2 or 3, wherein the first control valve (4) is an electromagnetic proportional pressure control valve.

5. The hydraulic system of the automobile hybrid transmission according to claim 4, wherein the cooling and lubricating oil path (1) comprises a clutch cooling branch (1a) communicated with a cooling cavity (3b) of the clutch (3), and the clutch cooling branch (1a) is provided with a second orifice (11).

6. The hydraulic system for a hybrid transmission of a vehicle according to claim 5, further comprising a flow control valve (12), a control valve core (12a) of the flow control valve (12) divides an inner cavity of the flow control valve (12) into a spring cavity II (12b) positioned at the left end and a reversing pilot pressure cavity II (12c) positioned at the right end, the flow control valve (12) is also provided with a second oil inlet (12d) and an oil outlet (12e), the oil outlet (12e) is connected with a clutch cooling branch (1a) which is positioned on one side of the throttle hole II (11) close to the cooling cavity (3b) of the clutch (3), the second oil inlet (12d) is connected with a clutch cooling branch (1a) located on the other side of the second throttling hole (11), and a second return spring (12f) is arranged in the second spring cavity (12 b).

7. The hydraulic system of the automobile hybrid transmission according to claim 5, wherein the cooling and lubricating oil path (1) further comprises a motor cooling branch (1b) and a shaft cooling branch (1c), and the motor cooling branch (1b) and the shaft cooling branch (1c) are respectively provided with a third throttle hole (17) and a fourth throttle hole (18).

8. The hydraulic system of the automotive hybrid transmission as defined in claim 7, characterized in that the motor cooling branch (1b) has a first branch (1b1) for P1 motor cooling and a second branch (1b2) for P3 motor cooling, and the first branch (1b1) and the second branch (1b2) have a fifth orifice (19) and a sixth orifice (20), respectively.

9. The hydraulic system of the automotive hybrid transmission according to claim 1, 2 or 3, characterized in that a first relief valve (13) and a first pressure sensor (14) are further provided on the high-pressure oil passage (2).

10. The hydraulic system of a hybrid transmission for a vehicle according to claim 1, 2 or 3, wherein a high-pressure filter (15) is further provided on the high-pressure oil path (2).

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