A multi-gear hybrid vehicle hydraulic control system

Abstract

This invention discloses a hydraulic control system for a multi-speed hybrid vehicle, including a system oil circuit, a lubrication and cooling oil circuit, a P1 motor cooling oil circuit, a P3 motor cooling oil circuit, a clutch solenoid valve control circuit, a clutch solenoid valve control circuit, a clutch control oil circuit one, a clutch control oil circuit two, a system solenoid valve control oil circuit, and a filtration system. This invention belongs to the field of hybrid transmission technology, specifically referring to a hydraulic control system for a multi-speed hybrid vehicle that can meet the requirements of multi-speed clutch engagement, disengagement, rapid gear switching, and cooling and lubrication.

Description

Technical Field

[0001] This invention belongs to the field of hybrid transmission technology, specifically referring to a hydraulic control system for multi-speed hybrid vehicles. Background Technology

[0002] With increasingly stringent national policies on emissions standards for gasoline-powered vehicles, and given the short driving range of pure electric vehicles, hybrid vehicles represent a crucial strategic step in the transition from gasoline to pure electric vehicles. Hybrid technology is rapidly evolving, expanding from single-mode hybrid to multi-mode hybrid, significantly improving the efficiency of vehicle drive systems. The hydraulic control module is the heart of a hybrid vehicle; it is essential for switching between pure electric and series / parallel modes, clutch shifting, and the cooling and lubrication of the motor and gear shafts.

[0003] The functions of hydraulic control modules vary depending on the type of hybrid vehicle and its usage scenario. Plug-in hybrids and hybrid electric vehicles (HEVs) have different cooling and lubrication requirements due to their different pure electric ranges, resulting in differences in the cooling and lubrication circuits of their hydraulic control modules. Research on hydraulic control modules for engine-driven multi-speed hybrid transmissions is limited; compared to single-speed transmissions, multi-speed hybrid transmissions add shifting functionality. Parallel-mode engine-driven transmissions use hydraulically controlled friction plate clutches for engagement and disengagement, offering advantages such as high control precision, fast response, and high reliability. The hydraulic control module for multi-speed hybrids increases the control circuitry based on the number of clutches. During gear shifting, the hydraulic control system must respond quickly, control precisely, and maintain a certain level of reliability. Therefore, a hydraulic control system needs to be designed to meet the requirements of multi-speed clutch engagement and disengagement, rapid gear shifting, and adequate cooling and lubrication. Summary of the Invention

[0004] To address the aforementioned challenges, this invention provides a multi-speed hybrid transmission hydraulic control system. Based on the driving scenarios of hybrid vehicles, this hydraulic control module can adaptively adjust the clutch pressure and the amount of cooling and lubrication flow. It can quickly and accurately control the clutch pressure, enabling the switching between series and parallel operation of the hybrid vehicle, as well as gear shifting in parallel mode. The engine's efficient operating range covers a wider range of vehicle speeds, resulting in better fuel economy. Furthermore, it is compatible with the lubrication and cooling needs of multiple scenarios, including pure electric, series, parallel, and low-temperature starting.

[0005] To achieve the above functions, the technical solution adopted by the present invention is as follows: a hydraulic control system for a multi-speed hybrid vehicle, including a system oil circuit, a lubrication and cooling oil circuit, a P1 motor cooling oil circuit, a P3 motor cooling oil circuit, a clutch solenoid valve control circuit, a clutch solenoid valve control circuit, a clutch control oil circuit, a clutch control oil circuit, a system solenoid valve control oil circuit, and a filtration system.

[0006] Furthermore, the lubrication and cooling oil circuit includes a second oil pump, a safety valve, a system valve, an oil temperature controller, and a cooling flow distribution valve. The second oil pump is an electronic pump, with its inlet connected to the oil pan and its outlet connected to the oil temperature controller. The system valve's discharge port is connected to the cooling flow distribution valve's inlet via the oil temperature controller. The oil temperature controller's outlet is connected to the cooling flow distribution valve's inlet. The cooling flow distribution valve has two outlets, connected to the P1 motor cooling oil circuit and the P3 motor cooling oil circuit, respectively. The P1 motor cooling oil circuit provides cooling flow to the P1 motor, while the P3 motor cooling oil circuit provides cooling and lubrication flow to the P3 motor and gear shaft.

[0007] Furthermore, the control oil circuit of the clutch solenoid valve includes a clutch solenoid valve and a clutch reversing valve. The clutch reversing valve has two oil inlets, and the oil outlet of the clutch solenoid valve is connected to the oil inlet of the clutch reversing valve.

[0008] The clutch solenoid valve control circuit includes a clutch solenoid valve and a clutch directional valve, and the clutch solenoid valve control circuit and the clutch control circuit are connected by the clutch directional valve.

[0009] The clutch reversing valve connects the clutch solenoid valve control oil circuit to the clutch control oil circuit; the clutch solenoid valve control oil circuit and the clutch control oil circuit are connected by the clutch reversing valve.

[0010] The system oil circuit includes a first oil pump, a system valve, and a system solenoid valve. The first oil pump is a mechanical pump driven by the engine. The oil inlet of the first oil pump is connected to the oil pan. The oil outlet of the first oil pump is connected to the solenoid oil supply end, the first oil supply end of the clutch solenoid valve, the second oil supply end of the clutch solenoid valve, the feedback end of the system valve, the oil inlet of the system valve, and the pilot end of the cooling flow distribution valve.

[0011] Furthermore, the first clutch control oil circuit includes an accumulator, a pressure sensor, and a clutch; the second clutch control oil circuit includes an accumulator, a pressure sensor, and a clutch.

[0012] It is worth noting that the filtration system includes a coarse filter, a fine filter, and a small filter screen; after the oil circulates within the hydraulic system a certain number of times, the purpose of cleaning the oil is achieved.

[0013] The functions of all the above circuits are to provide pressure to the clutch and to provide cooling flow to each system. The function of providing pressure to the clutch is achieved by the system oil circuit, the clutch solenoid valve one control oil circuit, the clutch solenoid valve two control oil circuit, the clutch control oil circuit one, the clutch control oil circuit two, and the system solenoid valve control oil circuit. The function of providing cooling flow is achieved by the system oil circuit, the lubrication cooling oil circuit, the P1 motor cooling oil circuit, and the P3 motor cooling oil circuit.

[0014] The system's oil circuit establishes the oil pressure of the entire hydraulic system, ensuring the oil supply pressure of clutch solenoid valve one and clutch solenoid valve two. The oil pressure of the control oil circuit of clutch solenoid valve one is controlled by clutch solenoid valve two, and the opening and closing of the clutch reversing valve is controlled by the clutch reversing valve. When clutch one meets both the oil pressure and the clutch reversing valve opening conditions, clutch one is engaged; the same applies to clutch two.

[0015] The system oil circuit is connected to the lubrication and cooling oil circuit through the system valve. The oil pumped out by the first oil pump builds pressure through the system oil circuit and discharges the excess flow to the lubrication and cooling oil circuit through the oil discharge port of the system valve. At the same time, the oil pumped out by the second oil pump is directly input into the lubrication and cooling oil circuit. Then, the flow distribution to the P1 motor cooling oil circuit and the P3 motor cooling oil circuit is realized through the cooling flow distribution valve.

[0016] The beneficial effects of the above structure are as follows: The present invention is designed for the characteristics of hybrid vehicle operation and meets the functional requirements of hybrid pure electric, series and parallel modes; the operating modes of hybrid vehicles and dual-clutch vehicles are different, the control strategies are different, and the functions and the ways of realizing the functions are also different.

[0017] 1. A dual-pump structure is adopted, with an engine-driven mechanical pump serving as the high-pressure pump and an electric pump serving as the low-pressure pump, solving the following problems:

[0018] (1) The flow rate of the electronic pump does not depend on the engine speed and wheel speed, thus meeting the cooling and lubrication flow requirements of the vehicle in pure electric mode and low-speed, high-torque driving conditions.

[0019] (2) The oil pressure for clutch engagement is provided by the first oil pump. The clutch can only engage when the engine is running. Therefore, it is necessary to avoid the situation where the clutch engages abnormally when the engine is not running, causing the wheels to drag the engine backward.

[0020] (3) In pure electric mode, when starting the vehicle in extremely cold conditions, the electric pump does not provide flow or provides low flow, which reduces the heat exchange between the oil and coolant, allowing the transmission oil to heat up quickly and improving overall efficiency.

[0021] (4) Vehicle series type: When starting the vehicle in extremely cold conditions, the electronic pump reverses and pumps the cooling flow to the oil inlet of the high-pressure pump, reducing the heat exchange between the oil and the coolant, allowing the transmission oil to heat up quickly and improving overall efficiency.

[0022] 2. The lubrication and cooling oil circuit design incorporates a flow distribution valve, which addresses the following issues:

[0023] (1) In pure electric mode, the flow distribution valve is closed, and all the flow of P1 motor is distributed to P3 motor, reducing the total flow output of oil pump, thereby improving vehicle efficiency.

[0024] (2) In series and parallel modes, the total cooling and lubrication flow is distributed to motor P1, motor P3, and gear shaft.

[0025] 3. A clutch reversing valve was designed, and the system solenoid valve controls the opening and closing of the clutch reversing valve. In pure electric mode and series mode, the clutch reversing valve is in the closed state, and the clutch cylinder is connected to the oil pan. In parallel mode, the system pressure increases, keeping the clutch reversing valve in the open state. The main functions of the clutch reversing valve are as follows:

[0026] (1) The output pressure of the direct drive proportional solenoid valve is directly proportional to the current. In practical applications, when the solenoid valve is depressurized by adjusting the current, the clutch pressure cannot be completely unloaded to 0, which may lead to abnormal clutch engagement. When the vehicle switches from parallel mode to series mode, the clutch cylinder is directly connected to the oil pan by closing the clutch reversing valve, so that the clutch oil pressure is unloaded to zero, reducing the risk of abnormal clutch engagement.

[0027] (2) When the clutch solenoid valve is stuck, if the clutch pressure cannot be unloaded by controlling the current of the solenoid valve, the clutch reversing valve can be closed to unload the clutch oil pressure, so that the vehicle can quickly switch from parallel mode to series mode.

[0028] 4. Taking a two-speed hybrid as an example, two clutches are used for switching, with two independent clutch control oil circuits. Clutch control oil circuit one controls the engagement and disengagement of clutch one, and clutch control oil circuit two controls the engagement and disengagement of clutch two. When switching from series mode to parallel mode, clutch one engages first, and clutch solenoid valve one outputs pressure. When shifting in parallel mode, clutch two engages while clutch one disengages. Engagement process: when clutch one is not fully disengaged, clutch two begins to engage. At this time, both clutches are in a slipping state. This stage is the shift transition period to avoid interruption of vehicle power. When clutch one is fully disengaged and clutch two is fully engaged, the shift ends.

[0029] 5. A filtration system was designed. A coarse filter was installed at the oil pump inlet to isolate large particles of impurities, reducing their entry into the valve plate and oil pump. A small filter was added to the clutch circuit to prevent impurities in the clutch cylinder from flowing back to the valve plate and causing the valve core and solenoid valve to stick. A fine filter was added to the cooling and lubricating oil circuit to filter out fine impurities in the oil. The fine filter contains impurities and filters the oil, therefore it needs to be replaced regularly to improve the system's cleaning efficiency. When the transmission system is running, wear-related impurities enter the oil. The filtration system, consisting of the coarse filter, small filter, and fine filter, causes the oil to circulate within the hydraulic system a certain number of times, achieving the purpose of cleaning the oil. Attached Figure Description

[0030] Figure 1 A schematic diagram of a multi-speed hybrid vehicle hydraulic control system provided by the present invention;

[0031] Figure 2 This is a schematic diagram of the shift transition period of the hydraulic control system for multi-speed hybrid vehicles provided by the present invention.

[0032] Among them, 10. Engine, 11. First oil pump, 12. Second oil pump, 21. System electronic valve, 22. Clutch solenoid valve one, 23. Clutch solenoid valve two, 31. System valve, 32. Clutch reversing valve, 33. Cooling flow distribution valve, 34. Safety valve, 41. Coarse filter, 42. Fine filter, 43. Small filter screen, 51. Accumulator, 52. Pressure sensor, 53. Clutch one, 54. Clutch two, 55. Oil temperature controller, 60. Oil pan, 100. System oil circuit, 110. Lubrication and cooling oil circuit, 111. P1 motor cooling oil circuit, 112. P3 motor cooling oil circuit, 120. Clutch solenoid valve one control oil circuit, 121. Clutch solenoid valve two control oil circuit, 122. Clutch control oil circuit one, 123. Clutch control oil circuit two, 130. System solenoid valve control oil circuit. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The invention will be further described in detail below with reference to the accompanying drawings.

[0035] like Figure 1 and Figure 2 As shown, the multi-speed hybrid vehicle hydraulic control system provided by the present invention includes a system oil circuit 100, a lubrication and cooling oil circuit 110, a P1 motor cooling oil circuit 111, a P3 motor cooling oil circuit 112, a clutch solenoid valve control oil circuit 120, a clutch solenoid valve control oil circuit 121, a clutch control oil circuit 122, a clutch control oil circuit 123, a system solenoid valve control oil circuit 130, and a filtration system.

[0036] The lubrication and cooling oil circuit 110 includes a second oil pump 12, a safety valve 34, a system valve 31, an oil temperature controller 55, and a cooling flow distribution valve 33. The second oil pump 12 is an electronic pump. The oil inlet of the second oil pump 12 is connected to the oil pan 60, and the oil outlet of the second oil pump 12 is connected to the temperature controller. The oil outlet of the system valve 31 is connected to the oil temperature controller 55. The oil outlet of the oil temperature controller 55 is connected to the oil inlet of the cooling flow distribution valve 33. The cooling flow distribution valve 33 has two oil outlets, which are connected to the P1 motor cooling oil circuit 111 and the P3 motor cooling oil circuit 112, respectively. The P1 motor cooling oil circuit 111 is responsible for providing cooling flow to the P1 motor. The P3 motor cooling oil circuit 112 is responsible for providing cooling and lubrication flow to the P3 motor and gear shaft.

[0037] The clutch solenoid valve control oil circuit 120 includes a clutch solenoid valve 22 and a clutch directional valve 32. The clutch directional valve 32 has two oil inlets, and the oil outlet of the clutch solenoid valve 22 is connected to the oil inlet of the clutch directional valve 32.

[0038] The control oil circuit 121 of the clutch solenoid valve 2 includes the clutch solenoid valve 23 and the clutch reversing valve 32. The oil outlet of the clutch solenoid valve 23 is connected to the oil inlet of the clutch reversing valve 32.

[0039] The clutch reversing valve 32 connects the clutch solenoid valve control oil circuit 120 to the clutch control oil circuit 122; the clutch reversing valve 32 connects the clutch solenoid valve control oil circuit 121 to the clutch control oil circuit 123.

[0040] The system oil circuit 100 includes a first oil pump 11, a system valve 31, and a system solenoid valve 21. The first oil pump 11 is a mechanical pump driven by the engine 10. The oil inlet of the first oil pump 11 is connected to the oil pan 60. The oil outlet of the first oil pump 11 is connected to the solenoid oil supply end, the oil supply end of clutch solenoid valve 1 22, the oil supply end of clutch solenoid valve 23, the feedback end of system valve 31, the oil inlet of system valve 31, and the pilot end of cooling flow distribution valve 33.

[0041] Clutch control oil circuit 122 includes accumulator 51, pressure sensor 52 and clutch 1 53; clutch control oil circuit 2 123 includes accumulator 51, pressure sensor 52 and clutch 2 54.

[0042] It is worth noting that the filtration system includes a coarse filter 41, a fine filter 42, and a small filter 43. The coarse filter 41 is designed at the front end of the oil pump inlet to isolate large particles of impurities and reduce the entry of large particles of impurities into the valve plate and oil pump. The coarse filter 41 is added to the clutch circuit to prevent impurities in the clutch cylinder from flowing back to the valve plate and causing the valve core and solenoid valve to stick. A fine filter 42 is added to the cooling and lubricating oil circuit to filter out small impurities in the oil. The fine filter 42 contains impurities and filters the oil, so it needs to be replaced regularly to improve the system's cleaning efficiency. When the transmission system is running, wear impurities enter the oil. The filtration system composed of the coarse filter 41, the fine filter 42, and the small filter 43 makes the oil circulate in the hydraulic system a certain number of times to achieve the purpose of cleaning the oil.

[0043] In practical use, hybrid vehicles switch between three modes during operation: pure electric, series, and parallel. In pure electric mode, the engine (10) does not start; in series and parallel modes, the engine (10) starts. The dual-motor structure of hybrid vehicles has a high demand for cooling flow. Using a single pump would require a large-displacement pump. Furthermore, for the low-speed, high-torque operation in pure electric mode, the low speed of the single mechanical pump's drive source means the cooling flow is insufficient to meet the motor's needs. Therefore, the hydraulic system of hybrid vehicles employs a dual-pump structure: a combination of a mechanical pump and an electronic pump.

[0044] like Figure 1 As shown, the first oil pump 11 is a mechanical pump driven by the engine 10, providing the flow rate with the oil pressure required for clutch engagement, with excess oil supplied to the cooling and lubrication circuit. The second oil pump 12 is an electronic oil pump, providing only the cooling and lubrication flow rate. In series mode and direct drive mode, the system cooling flow rate mainly comes from the first oil pump 11, with the second oil pump 12 supplementing the difference to meet system requirements. In pure electric mode, under low-speed, high-torque conditions, the engine 10 is not running and the first oil pump 11 is not operating. Since the wheel speed is low, the second oil pump 12, being an electronic pump, is unaffected by engine speed or vehicle speed, providing sufficient flow rate according to system needs.

[0045] When starting a vehicle in low-temperature conditions, the transmission fluid needs to warm up quickly to improve transmission efficiency. In pure electric mode, the second oil pump 12 can be controlled to either not start or only provide a low flow rate. In series mode, during a cold start, the first oil pump 11 outputs flow due to the engine 10 starting. The flow rate of oil pumped by the first oil pump is determined by the engine speed and is uncontrollable. Therefore, the second oil pump 12 can be reversed to pump oil from the cooling lubrication circuit to the inlet of the first oil pump 11, reducing the cooling lubrication flow to various components and simultaneously reducing the heat exchange between the oil and coolant, thereby rapidly increasing the oil temperature.

[0046] System solenoid valve 21 is a pilot-operated proportional solenoid valve. Its function is to control the pressure of the system hydraulic fluid and the opening and closing of the clutch directional valve 32. System solenoid valve 21, together with system valve 31, forms an open-loop control system. The system pressure is controlled by adjusting the current of system solenoid valve 21. This system pressure serves as the supply pressure for clutch solenoid valve 22 and clutch solenoid valve 23. The spring force of system valve 31 is designed to provide the initial system pressure value. In parallel mode, the system pressure is adjusted according to the clutch pressure requirements to reduce pump efficiency losses.

[0047] In the pure electric mode, since engine 10 and generator P1 are not operating, motor P1 does not require cooling and lubrication flow. However, in plug-in hybrid systems, motor P3 operates for extended periods, requiring more cooling flow. The opening and closing of flow distribution valve 33 is controlled by system pressure. In pure electric mode, the system pressure is zero, and the valve is closed, distributing all flow from motor P1 to motor P3, reducing the flow output from the oil pump. In series and parallel modes, when engine 10 starts, the initial system pressure is not zero due to the spring force. The initial system pressure is designed to open flow distribution valve 33, distributing cooling and lubrication flow to motors P1 and P3, and the gear shaft. The opening pressure of flow distribution valve 33 is designed to ensure that the initial system oil pressure is sufficient to open it, allowing the opening and closing of the flow distribution valve to be controlled by the starting and stopping of engine 10.

[0048] The cooling and lubrication oil circuit is designed with a safety valve 34. When the cooling and lubrication pressure is too high, the safety valve 34 opens to unload the oil pressure in the cooling and lubrication oil circuit.

[0049] The clutch reversing valve 32 is designed, and the system solenoid valve 21 controls the opening and closing of the clutch reversing valve 32. In pure electric mode and series mode, the clutch reversing valve 32 is in the closed state, and clutch one 53 and clutch two 54 are respectively connected to the oil pan 60; in parallel mode, the system solenoid valve 21 controls the system pressure, causing the clutch reversing valve 32 to open.

[0050] The main functions of the clutch reversing valve 32 are as follows:

[0051] (1) The output pressure of the direct-drive proportional solenoid valve is directly proportional to the current. When the solenoid valve is depressurized, it cannot completely unload the clutch pressure to 0, which may lead to abnormal clutch engagement. When the vehicle switches from parallel mode to series mode, the clutch reversing valve 32 is closed, and the oil pressure of clutch 1 53 and clutch 2 54 is directly connected to the oil pan, which can unload the oil pressure of the two clutches to zero.

[0052] (2) When clutch solenoid valve 1 22 and clutch solenoid valve 23 are stuck, and the clutch pressure cannot be unloaded by controlling the current of the solenoid valve, the clutch reversing valve 32 is closed to unload the clutch oil pressure, so that the vehicle can quickly switch from parallel mode to series mode.

[0053] Friction plate clutches, with their slippery function, reduce the jerkiness during engagement or gear shifting. They typically use a direct-drive proportional solenoid valve to control clutch engagement and disengagement. Two-speed hybrids employ two clutches, each with its own independent clutch control oil circuit. When switching from series to parallel mode, clutch one engages first; as vehicle speed increases, clutch two engages slowly while clutch one disengages slowly.

[0054] like Figure 2 As shown, when clutch 1 (53) is not fully disengaged, clutch 2 (54) begins to engage. At this time, both clutches are in a slipping state. This stage is the shift transition period to avoid interruption of vehicle power. When clutch 1 (53) is fully disengaged and clutch 2 (54) is fully engaged, the shift ends.

[0055] The clutch oil circuit is designed with an accumulator 51 to reduce the impact of clutch engagement and shifting, and to stabilize oil pressure.

[0056] The clutch oil circuit is designed with a pressure sensor 52, which enables the vehicle controller to monitor pressure stability in real time and adaptively adjust the clutch cylinder pressure.

[0057] The filtration system is designed with a coarse filter 41 at the oil pump inlet to isolate large particles and reduce their entry into the valve plate and oil pump. A small filter 43 is added to the clutch circuit to prevent impurities in the clutch cylinder from flowing back to the valve plate and causing the valve core and solenoid valve to stick. A fine filter 42 is added to the cooling and lubrication oil circuit to filter out fine impurities in the oil. The fine filter 42 contains impurities and filters the oil, therefore it needs to be replaced regularly to improve the system's cleaning efficiency. When the transmission system is running, wear-related impurities enter the oil. The filtration system, consisting of the coarse filter 41, small filter 43, and fine filter 42, circulates the oil within the hydraulic system a certain number of times, achieving the purpose of cleaning the oil.

[0058] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A hydraulic control system for a multi-speed hybrid vehicle, characterized in that: The system includes an oil circuit, a lubrication and cooling oil circuit, a P1 motor cooling oil circuit, a P3 motor cooling oil circuit, a clutch solenoid valve control circuit, a clutch solenoid valve control circuit, a clutch control circuit one, a clutch control circuit two, a system solenoid valve control oil circuit, and a filtration system. The lubrication and cooling oil circuit includes a second oil pump, a safety valve, a system valve, an oil temperature controller, and a cooling flow distribution valve. The second oil pump is an electronic pump; its inlet is connected to the oil pan, and its outlet is connected to the oil temperature controller. The system valve's outlet is connected to the cooling flow distribution valve's inlet via the oil temperature controller. The cooling flow distribution valve has two outlets, connected to the P1 motor cooling oil circuit and the P3 motor cooling oil circuit respectively. The P1 motor cooling oil circuit provides cooling flow to the P1 motor. The P3 motor... The cooling oil circuit is responsible for providing cooling and lubrication flow to the P3 motor and gear shaft; the filtration system includes a coarse filter, a fine filter, and a small filter screen; the system oil circuit includes a first oil pump, a system valve, and a system solenoid valve. The first oil pump is a mechanical pump driven by the engine. The oil inlet of the first oil pump is connected to the oil pan, and the oil outlet of the first oil pump is connected to the oil supply end of the system solenoid valve, the first oil supply end of the clutch solenoid valve, the second oil supply end of the clutch solenoid valve, the feedback end of the system valve, the oil inlet of the system valve, and the pilot end of the cooling flow distribution valve. The oil outlet of the system valve is connected to the lubrication oil circuit; the system solenoid valve is a pilot-operated proportional solenoid valve. The system solenoid valve is used to control the pressure of the system oil and the opening and closing of the clutch reversing valve. The system solenoid valve and the system valve form an open-loop control, and the system pressure is controlled by adjusting the current of the system solenoid valve.

2. The hydraulic control system for a multi-speed hybrid vehicle according to claim 1, characterized in that: The clutch solenoid valve control circuit includes a clutch solenoid valve and a clutch reversing valve. The clutch reversing valve has two oil inlets, and the oil outlet of the clutch solenoid valve is connected to the oil inlet of the clutch reversing valve.

3. The hydraulic control system for a multi-speed hybrid vehicle according to claim 2, characterized in that: The control oil circuit of the second clutch solenoid valve includes the second clutch solenoid valve and the clutch reversing valve, and the oil outlet of the second clutch solenoid valve is connected to the oil inlet of the clutch reversing valve.

4. The hydraulic control system for a multi-speed hybrid vehicle according to claim 3, characterized in that: The clutch solenoid valve one control oil circuit and the clutch control oil circuit one are connected by a clutch reversing valve; the clutch solenoid valve two control oil circuit and the clutch control oil circuit two are connected by a clutch reversing valve.

5. A multi-speed hybrid vehicle hydraulic control system according to claim 4, characterized in that: The first clutch control circuit includes an accumulator, a pressure sensor, and a clutch; the second clutch control circuit includes an accumulator, a pressure sensor, and a clutch.

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