Vehicle and hydraulic system thereof

Abstract

A vehicle, provided with a hydraulic system. The hydraulic system comprises a proportional solenoid valve (170), a pressure control slide valve (140), and a target mechanical valve set. The pressure control slide valve (140) is a mechanical valve. The target mechanical valve set comprises at least one mechanical valve. The proportional solenoid valve (170) is configured such that, by controlling the proportional solenoid valve (170), the pressure control slide valve (140) and the target mechanical valve set are controlled.

Description

Vehicles and their hydraulic systems

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311097179.2, filed on August 28, 2023, entitled “Vehicle and Hydraulic System Thereof,” the entire contents of which are incorporated herein for all purposes. Technical Field

[0003] The present application relates to the field of vehicle technology, and in particular to a hydraulic system of a vehicle and a vehicle. Background Art

[0004] Currently, control valves (such as pressure control valves, flow control valves, etc.) in a vehicle's hydraulic system are typically solenoid valves, which are relatively expensive, and each solenoid valve needs to be controlled individually, making the control of the hydraulic system relatively complex.

[0005] Therefore, improvements are needed to at least partially solve the above problems.

[0006] Summary of the Invention

[0007] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. The Summary of the Invention is not intended to limit the key features and essential features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] In order to at least partially solve the above problems, according to a first aspect of the present invention, there is provided a hydraulic system for a vehicle, comprising:

[0009] A proportional solenoid valve, a pressure control slide valve and a target mechanical valve group, wherein the pressure control slide valve is a mechanical valve and the target mechanical valve group includes at least one mechanical valve;

[0010] The proportional solenoid valve is configured to control the pressure control spool valve and the target mechanical valve group by controlling the proportional solenoid valve.

[0011] Exemplarily, the target mechanical valve group includes a motor flow control slide valve, a relief slide valve, and a switch control slide valve, wherein the motor flow control slide valve, the relief slide valve, and the switch control slide valve are all mechanical valves.

[0012] Exemplarily, the pressure of the oil outlet of the proportional solenoid valve and the system oil pressure of the oil inlet of the pressure control slide valve cooperate to regulate the opening of the pressure control slide valve;

[0013] The pressure of the oil outlet of the proportional solenoid valve and the oil pressure of the oil inlet of the flow control slide valve regulate the opening of the flow control slide valve;

[0014] The pressure of the oil outlet of the proportional solenoid valve and the pressure of the feedback end of the overflow slide valve cooperate to regulate the overflow opening of the overflow slide valve;

[0015] The opening and closing of the switch control slide valve is related to the pressure of the oil outlet of the proportional solenoid valve, wherein the switch control slide valve is configured to open when the pressure of the oil outlet of the proportional solenoid valve is greater than or equal to a set threshold, and to close when the pressure of the oil outlet of the proportional solenoid valve is less than the set threshold.

[0016] Exemplarily, the vehicle includes a fuel tank and a first fuel pump;

[0017] The oil outlet of the first oil pump is communicated with the oil inlet of the proportional solenoid valve and the oil inlet of the pressure control slide valve respectively;

[0018] The oil inlet of the motor flow control slide valve is communicated with the oil outlet of the pressure control slide valve, the oil outlet of the motor flow control slide valve is communicated with the motor of the vehicle, and the control port of the motor flow control slide valve is communicated with the oil outlet of the proportional solenoid valve;

[0019] The oil inlet of the overflow slide valve is communicated with the oil outlet of the pressure control slide valve, the oil outlet of the overflow slide valve is communicated with the oil inlet of the first oil pump, the control port of the overflow slide valve is communicated with the oil outlet of the proportional solenoid valve, and the feedback end of the overflow slide valve is communicated with the oil inlet of the overflow slide valve;

[0020] The oil inlet of the switch control slide valve is communicated with the oil inlet of the pressure control slide valve, the oil outlet of the switch control slide valve is communicated with the oil inlet of the clutch control valve of the vehicle, and the control port of the switch control slide valve is communicated with the oil outlet of the proportional solenoid valve.

[0021] Exemplarily, the hydraulic system further includes a second oil pump and a cooling module;

[0022] The oil inlet of the second oil pump is connected to the oil tank, and the oil outlet of the second oil pump and the oil outlet of the pressure control slide valve are both connected to the oil inlet of the cooling module;

[0023] The oil outlet of the cooling module is communicated with the oil inlet of the motor flow control slide valve.

[0024] Exemplarily, the first oil pump and the second oil pump are both mechanical oil pumps, the first oil pump is connected to the engine of the vehicle, and the second oil pump is connected to the wheel end of the vehicle;

[0025] The vehicle also includes a one-way valve, a first end of the one-way valve is connected to the oil inlet of the second oil pump, and a second end of the one-way valve is connected to the oil outlet of the second oil pump, and the flow direction of the one-way valve is from the first end of the one-way valve to the second end of the one-way valve.

[0026] Exemplarily, when the vehicle is in the first operating mode, the first oil pump is not operating, and the second oil pump is operating, and the proportional solenoid valve is controlled to be in a closed state, so as to control the system oil pressure at the oil inlet of the pressure control slide valve to be at a first oil pressure, control the motor flow control slide valve to be in a fully open state, and control the switch control slide valve to be in a closed state, wherein the control port of the overflow slide valve has no pressure, and the overflow slide valve is opened or closed according to the pressure at the feedback end; and / or,

[0027] When the vehicle is in the second operating mode, the first oil pump is in operation, the second oil pump is in operation, and the proportional solenoid valve is controlled to be in a first opening degree, so as to control the system oil pressure at the oil inlet of the pressure control slide valve to be in a second oil pressure, control the motor flow control slide valve to be in a first open state, control the overflow slide valve to be in an open state, and control the switch control slide valve to be in a closed state; and / or,

[0028] When the vehicle is in the third operating mode, the first oil pump is in operation, the second oil pump is in operation, and the proportional solenoid valve is controlled to be in a second opening degree, so as to control the system oil pressure at the oil inlet of the pressure control slide valve to be in a third oil pressure, control the motor flow control slide valve to be in a second open state, control the overflow slide valve to be in an open state, and control the switch control slide valve to be in an open state; and / or,

[0029] When the vehicle is in the fourth operating mode, the first oil pump is in operation, the second oil pump is in operation, and the proportional solenoid valve is controlled to be in a third opening degree, so as to control the system oil pressure at the oil inlet of the pressure control slide valve to be in a fourth oil pressure, control the motor flow control slide valve to be in a third open state or closed state, control the overflow slide valve to be in an open state, and control the switch control slide valve to be in an open state; and / or,

[0030] When the vehicle is in the fifth working mode, the first oil pump is working and the second oil pump is not working. By controlling the proportional solenoid valve to be in the fourth opening degree, the system oil pressure of the oil inlet of the pressure control slide valve is controlled to be in the fifth oil pressure, the motor flow control slide valve is controlled to be in the closed state, the overflow slide valve is controlled to be in the open state, and the switch control slide valve is controlled to be in the open state.

[0031] Exemplarily, the first opening is smaller than the second opening, the second opening is smaller than the third opening, and the third opening is smaller than the fourth opening;

[0032] The first oil pressure is less than or equal to the second oil pressure, the second oil pressure is less than the third oil pressure, the third oil pressure is less than the fourth oil pressure, and the fourth oil pressure is less than the fifth oil pressure;

[0033] The opening degree in the first opening state is less than or equal to the opening degree in the fully open state, the opening degree in the second opening state is less than the opening degree in the first opening state, and the opening degree in the third opening state is less than the opening degree in the second opening state.

[0034] Exemplarily, the first operating mode is a pure electric mode, the second operating mode is a series mode, the third operating mode is a parallel mode, the fourth operating mode is an engine direct drive mode, and the fifth operating mode is a parking power generation mode.

[0035] Exemplarily, the feedback end of the overflow slide valve is connected to the oil inlet of the cooling module, and the pressure of the feedback end is positively correlated with the oil viscosity characteristics of the oil in the oil inlet of the cooling module.

[0036] Exemplarily, the viscosity of the oil at the oil inlet of the cooling module is negatively correlated with the temperature of the oil.

[0037] Exemplarily, the hydraulic system further includes a shift solenoid valve;

[0038] The oil inlet of the shift solenoid valve is connected to the oil outlet of the switch control slide valve, the working oil port of the shift solenoid valve is connected to the shift unit of the vehicle, and the shift solenoid valve is used to control the shift unit to shift gears.

[0039] Exemplarily, the cooling module includes an oil cooler and a bypass pressure differential valve;

[0040] The oil inlet of the oil cooler is communicated with the oil outlet of the second oil pump, and the oil outlet of the oil cooler is communicated with the oil inlet of the motor flow control slide valve;

[0041] The oil inlet of the bypass pressure differential valve is connected to the oil inlet of the oil cooler, and the oil outlet of the bypass pressure differential valve is connected to the oil outlet of the oil cooler. The bypass pressure differential valve is used to open when the pressure difference between the oil inlet of the oil cooler and the oil outlet of the oil cooler exceeds a set threshold.

[0042] Exemplarily, the hydraulic system further includes a clutch flow control valve and a pressure differential check valve;

[0043] The oil inlet of the clutch flow control valve is communicated with the oil outlet of the cooling module, and the oil outlet of the clutch flow control valve is communicated with the clutch;

[0044] The inlet of the pressure differential one-way valve is connected to the oil inlet of the clutch flow control valve, and the outlet of the pressure differential one-way valve is connected to the oil outlet of the clutch flow control valve. The pressure differential one-way valve is used to keep the pressure difference between the oil inlet of the clutch flow control valve and the oil outlet of the clutch flow control valve constant.

[0045] According to a second aspect of the present invention, there is provided a vehicle comprising the hydraulic system described above.

[0046] According to the vehicle and its hydraulic system of the present invention, the pressure control slide valve and the target mechanical valve group (for example, including the motor flow control slide valve, the overflow slide valve, the switch control slide valve, etc.) are jointly controlled by the proportional solenoid valve, thereby realizing the adjustment of multiple parameters in the hydraulic system. The slide valve has significantly lower cost than the solenoid valve, and there is no need to control each valve separately, so the hydraulic system control is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The following drawings of this application are hereby incorporated as part of this application for understanding this application. The drawings show the embodiments of this application and their descriptions, and are used to explain the device and principle of this application. In the drawings,

[0048] FIG1 is a schematic structural block diagram of a hydraulic system according to a first embodiment of the present application;

[0049] FIG2 is a schematic structural block diagram of a hydraulic system according to a second embodiment of the present application;

[0050] FIG3 is a schematic structural block diagram of a hydraulic system according to a third embodiment of the present application;

[0051] FIG4 is a schematic structural diagram of a hydraulic system according to a fourth embodiment of the present application.

[0052] Explanation of reference numerals: 100, 100', 100" - hydraulic system, 110 - oil tank, 120 - first oil pump, 130 - second oil pump, 140 - pressure control slide valve, 150 - clutch control valve, 160 - motor flow control slide valve, 170 - proportional solenoid valve, 180 - overflow slide valve, 190 - switch control slide valve, 200 - clutch, 300 - motor; 1 - first oil pump, 2 - pressure filter, 3 - proportional solenoid valve, 4 - pressure control slide valve, 5 - pressure sensor, 6-Safety valve, 7-Switch control slide valve, 8-Buffer, 9-Check valve, 10-Shift solenoid valve, 11-Clutch control valve, 12-Check valve, 13-Pressure sensor, 14-Buffer, 15-First gear piston, 16-Second gear piston, 17-Gear position sensor, 18-Second oil pump, 19-Pressure filter, 20-Oil cooler, 21-Overflow slide valve, 22-Bypass pressure differential valve, 23-Check valve, 24-Motor flow control slide valve, 25-Pressure differential check valve, 26-Clutch flow control valve, 27-Bearing, 28-Generator, 29-Engine, 30-Clutch, 31-Motor, 32-Reducer, 33-Wheel, 34-Power battery, 35-Oil tank, 36-Suction filter, 37-49-Damping orifice. DETAILED DESCRIPTION

[0053] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it will be apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, some technical features well known in the art are not described in order to avoid confusion with the present application.

[0054] It should be understood that the present application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present application to those skilled in the art. In the drawings, the dimensions and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals throughout represent like elements.

[0055] It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Thus, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of this application.

[0056] Spatially relative terms, such as "below," "beneath," "beneath," "above," "upper," etc., may be used herein for convenience to describe the relationship of one element or feature to other elements or features illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientations depicted in the figures.

[0057] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0058] 1 , a hydraulic system 100 of a vehicle according to a first embodiment of the present application is exemplarily described. The vehicle may be a hybrid vehicle. The hydraulic system 100 includes an oil tank 110 , an oil pump unit, a pressure control slide valve 140 , a clutch control valve 150 , an electric motor flow control slide valve 160 , and a proportional solenoid valve 170 .

[0059] The oil pump unit includes a first oil pump 120 and a second oil pump 130. The oil inlet of the first oil pump 120 is connected to the oil tank 110, and the oil outlet of the first oil pump 120 is connected to the oil inlet of the pressure control spool valve 140, the oil inlet of the clutch control valve 150, and the oil inlet of the proportional solenoid valve 170. The oil inlet of the second oil pump 130 is connected to the oil tank 110, and the oil outlet of the second oil pump 130 is connected to the oil outlet of the pressure control spool valve 140. It should be noted that the term "connection" as used herein can mean direct connection (connection via a connecting pipe without other components) or indirect connection (connection via a connecting pipe with one or more other components). The oil inlets of the first and second oil pumps 120, 130 can be connected to the oil tank 110 via a suction filter, which is used to filter the oil to reduce the risk of subsequent control valve sticking. In this embodiment, both the first oil pump 120 and the second oil pump 130 can be mechanical oil pumps. The first oil pump 120 is connected to the vehicle's engine at a specific speed ratio, while the second oil pump 130 is connected to the vehicle's wheel ends (e.g., a differential on the vehicle) at a specific speed ratio. The oil pump unit also includes a one-way valve, the first end of which is connected to the oil inlet of the second oil pump 130, and the second end of which is connected to the oil outlet of the second oil pump 130. The oil flow direction of the one-way valve is from the first end to the second end of the one-way valve.

[0060] The pressure control slide valve 140 is a mechanical valve. The oil inlet of the pressure control slide valve 140 is connected to the oil inlet of the clutch control valve 150, and the oil outlet of the pressure control slide valve 140 is connected to the oil inlet of the motor flow control slide valve 160. The pressure control slide valve 140 is used to control the system oil pressure at its oil inlet, that is, to control the pressure of the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, the oil inlet of the clutch control valve 150 and the oil inlet of the proportional solenoid valve 170.

[0061] The oil inlet of clutch control valve 150 communicates with the oil inlet of pressure control spool valve 140, and the oil outlet of clutch control valve 150 communicates with the vehicle's clutch 200. Clutch control valve 150 is used to control the engagement and disengagement of clutch 200. In this embodiment, clutch control valve 150 may be a solenoid valve. The vehicle's VCU (Vehicle Control Unit) is connected to clutch control valve 150, controlling the engagement and disengagement of clutch 200 through clutch control valve 150. In some embodiments, clutch control valve 150 may also be a pneumatic control valve or other suitable type of control valve.

[0062] The motor flow control spool valve 160 is a mechanical valve. Its oil inlet communicates with the oil outlet of the second oil pump 130 and the oil outlet of the pressure control spool valve 140. Its oil outlet communicates with the vehicle's electric motor 300. Oil from the second oil pump 130 and the pressure control spool valve 140 can enter the electric motor 300 through the motor flow control spool valve 160 to lubricate and cool the motor 300. The opening of the motor flow control spool valve 160 is positively correlated with the flow rate at its oil outlet. Specifically, the greater the opening of the motor flow control spool valve 160, the greater the flow rate at its oil outlet, and thus the greater the flow rate of oil entering the motor 300 for cooling and lubrication.

[0063] The oil inlet of the proportional solenoid valve 170 is connected to the oil outlet of the first oil pump 120. The oil outlet of the proportional solenoid valve 170 is also connected to the control port of the pressure control spool 140 and the control port of the motor flow control spool 160. The proportional solenoid valve 170 is used to control the system oil pressure at the oil inlet of the pressure control spool 140 and the opening of the motor flow control spool 160. That is, by controlling the proportional solenoid valve 170, the pressure control spool 140 and the motor flow control spool 160 are controlled. The pressure at the oil outlet of the proportional solenoid valve 170 and the system oil pressure at the oil inlet of the pressure control spool 140 cooperate to control the opening of the pressure control spool 140 (for example, the pressure control spool 140 may be provided with a feedback port that is connected to the oil inlet, and the pressure at the control port of the pressure control spool 140 and the pressure at the feedback port cooperate to control the opening of the pressure control spool 140). The pressure at the oil outlet of the proportional solenoid valve and the oil pressure at the oil inlet of the motor flow control spool 160 control the opening of the motor flow control spool. The pressure at the oil outlet of proportional solenoid valve 170 is positively correlated with the system oil pressure at the oil inlet of pressure control spool valve 140, and negatively correlated with the opening of motor flow control spool valve 160. Specifically, the higher the pressure at the oil outlet of proportional solenoid valve 170, the higher the system oil pressure at the oil inlet of pressure control spool valve 140, and the smaller the opening of motor flow control spool valve 160. In this embodiment, the vehicle's VCU is connected to proportional solenoid valve 170. By adjusting the current supplied to proportional solenoid valve 170, the pressure at the oil outlet of proportional solenoid valve 170 is controlled. Specifically, the pressure in the control oil circuit between the oil outlet of proportional solenoid valve 170, the control port of pressure control spool valve 140, and the control port of motor flow control spool valve 160 is controlled, thereby simultaneously controlling the system oil pressure at the oil inlet of pressure control spool valve 140 and the opening of motor flow control spool valve 160. The greater the current supplied to proportional solenoid valve 170, the greater the pressure at the oil outlet of proportional solenoid valve 170, the greater the system oil pressure at the oil inlet of pressure control spool valve 140 (the greater the pressure threshold for opening pressure control spool valve 140), and the smaller the opening of motor flow control spool valve 160. Proportional solenoid valve 170 can be a pilot proportional solenoid valve 170 or another type of proportional solenoid valve 170, and those skilled in the art can select the appropriate type as needed.

[0064] When the vehicle is in pure electric mode (EV mode), the motor 300 drives the wheels to rotate, the cooling demand of the motor 300 is high, the engine is not working, the clutch 200 has no engagement demand, the first oil pump 120 is not working, and the second oil pump 130 is working. In this case, no current can be provided to the proportional solenoid valve 170, so that the pressure of the control oil circuit is at a lower level, thereby controlling the pressure control slide valve 140 to be in a fully closed state, the system oil pressure of the oil inlet of the pressure control slide valve 140 is at a first oil pressure, and at the same time controlling the motor flow control slide valve 160 to be in a fully open state. At this time, a large amount of oil from the second oil pump 130 enters the motor 300 to lubricate and cool the motor 300.

[0065] When the vehicle is in series mode, motor 300 drives the wheels, requiring high cooling for motor 300. The engine is operating, clutch 200 is not engaged, and both first and second oil pumps 120 and 130 are operating. In this situation, a low current can be supplied to proportional solenoid valve 170, causing it to be in a first opening position and the pressure in the control oil circuit to be low. Consequently, pressure control spool valve 140 is controlled to be closed or open, and the system oil pressure at the oil inlet of pressure control spool valve 140 is in a second oil pressure, which is greater than or equal to the first oil pressure. Simultaneously, motor flow control spool valve 160 is controlled to be in a first opening position, which is a fully open position or a relatively large opening position. In other words, the opening in the first opening position is less than or equal to the opening in the fully open position. At this time, a large amount of oil from first oil pump 120 and pressure control spool valve 140 enters motor 300 to lubricate and cool it.

[0066] When the vehicle is in parallel mode, the motor 300 and the engine jointly drive the wheels. The cooling requirement for the motor 300 is low, and the clutch 200 needs to engage. The first oil pump 120 and the second oil pump 130 are both operating. In this situation, a larger current can be supplied to the proportional solenoid valve 170, causing the proportional solenoid valve 170 to be in a second opening position (greater than the first opening position), resulting in a higher pressure in the control oil circuit. Consequently, the control pressure control spool 140 is open, and the system oil pressure at the oil inlet of the control pressure control spool 140 is at a third oil pressure (greater than the second oil pressure). At this point, the pressure in the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control spool 140, the oil inlet of the clutch control valve 150, and the oil inlet of the proportional solenoid valve 170 is higher (having a higher upper pressure limit). Consequently, by controlling the clutch control valve 150, the clutch 200 can be effectively engaged without overpressure. The motor flow control slide valve 160 is controlled to be in a second open state, which is a state with a smaller opening degree, that is, the opening degree in the second open state is less than or equal to the opening degree in the first open state. At this time, a small amount of oil from the first oil pump 120 and the pressure control slide valve 140 enters the motor 300 to lubricate and cool the motor 300.

[0067] When the vehicle is in engine direct drive mode, the motor 300 is inoperative and requires no or minimal cooling. The engine drives the wheels, requiring the clutch 200 to engage. The first and second oil pumps 120 and 130 are both in operation. In this situation, a relatively high current can be supplied to the proportional solenoid valve 170, causing the proportional solenoid valve 170 to be at a third opening, which is greater than the second opening. Consequently, the pressure in the control oil circuit is relatively high, thereby opening the pressure control spool valve 140 and controlling the system oil pressure at the oil inlet of the pressure control spool valve 140 to be at a fourth oil pressure, which is greater than the third oil pressure. At this point, the pressure in the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control spool valve 140, the oil inlet of the clutch control valve 150, and the oil inlet of the proportional solenoid valve 170 is relatively high (having a relatively high upper pressure limit). Consequently, by controlling the clutch control valve 150, the clutch 200 can be effectively engaged without overpressure. And the motor flow control slide valve 160 is controlled to be in the third open state, the second open state is a state with a smaller opening degree or a closed state, that is, the opening degree in the third open state is less than or equal to the opening degree in the second open state. At this time, a small amount of oil from the first oil pump 120 and the pressure control slide valve 140 enters the motor 300 to lubricate and cool the motor 300 or does not enter the motor 300.

[0068] When the vehicle is in parking power generation mode, the engine operates to drive the generator, while motor 300 is inoperative and requires no cooling. Clutch 200 does not require engagement, and first oil pump 120 operates while second oil pump 130 does not operate. In this situation, a high current can be supplied to proportional solenoid valve 170, causing it to reach the fourth opening degree (which is greater than the third opening degree), resulting in a higher pressure in the control pressure oil circuit. Consequently, the system oil pressure at the oil inlet of control pressure control spool valve 140 reaches the fifth oil pressure (which is greater than the fourth oil pressure). Simultaneously, motor flow control spool valve 160 is fully closed.

[0069] That is to say, under the condition of a certain total drive demand, the cooling demand for the motor 300 decreases successively and the demand for the pressure of the pressure oil circuit increases successively in the pure electric mode / series mode, parallel mode, and direct drive mode. Utilizing this characteristic, the hydraulic system 100 of this embodiment jointly controls the pressure control slide valve 140 and the motor flow control slide valve 160 through the proportional solenoid valve 170 and the control oil circuit. The greater the current provided to the proportional solenoid valve 170, the higher the control oil circuit pressure, the greater the system oil pressure at the oil inlet of the pressure control slide valve 140 (the greater the pressure threshold for opening the pressure control slide valve 140) and the smaller the opening of the flow control valve. Accordingly, the higher the pressure upper limit of the pressure oil circuit, the smaller the flow of oil entering the motor 300 for cooling and lubrication. According to the hydraulic system 100 of this embodiment, without adding more solenoid valves, the pressure control slide valve 140 and the motor flow control slide valve 160 in the hydraulic system 100 are simultaneously controlled by a single proportional solenoid valve 170, thereby realizing the adjustment of the pressure upper limit of the pressure oil circuit and the cooling and lubrication flow of the motor 300. The control is simple and the cost is low, and the hydraulic system 100 has low energy consumption.

[0070] In some other embodiments, the vehicle may only have any one or more operating modes among pure electric mode, series mode, parallel mode, engine direct drive mode and parking power generation mode.

[0071] 2 , a hydraulic system 100 ′ of a vehicle according to a second embodiment of the present application is exemplarily described. The vehicle may be a hybrid vehicle. The hydraulic system 100 ′ includes an oil tank 110 , an oil pump unit, a pressure control slide valve 140 , a clutch control valve 150 , a relief slide valve 180 , and a proportional solenoid valve 170 .

[0072] The oil pump unit includes a first oil pump 120 and a second oil pump 130. The oil inlet of the first oil pump 120 is connected to the fuel tank 110, while the oil outlet of the first oil pump 120 is connected to the oil inlet of the pressure control spool valve 140, the oil inlet of the clutch control valve 150, and the oil inlet of the proportional solenoid valve 170. The oil inlet of the second oil pump 130 is connected to the fuel tank 110, while the oil outlet of the second oil pump 130 is connected to the oil outlet of the pressure control spool valve 140 and the vehicle's electric motor 300. The oil inlets of the first and second oil pumps 120, 130 can be connected to the fuel tank 110 via a suction filter, which filters the oil to reduce the risk of subsequent control valve sticking. In this embodiment, both the first oil pump 120 and the second oil pump 130 can be mechanical oil pumps. The first oil pump 120 is connected to the vehicle's engine at a specific speed ratio, while the second oil pump 130 is connected to the vehicle's wheel ends (e.g., the vehicle's differential) at a specific speed ratio. The oil pump unit also includes a one-way valve, the first end of which is connected to the oil inlet of the second oil pump 130, and the second end of which is connected to the oil outlet of the second oil pump 130. The flow direction of the one-way valve is from the first end to the second end of the one-way valve. When the vehicle is moving forward, the second oil pump 130 rotates forward to pump oil from the fuel tank 110 to the motor flow control spool valve 160. During this time, the one-way valve is closed. When the vehicle is reversing, the second oil pump 130 rotates backward. At this time, the one-way valve is opened, and oil circulates through the second oil pump 130 and the one-way valve, reducing the resistance to reverse rotation of the second oil pump 130 and preventing backflow. In some other embodiments, the first oil pump 120 may be a mechanical oil pump, and the second oil pump 130 may be an electronic oil pump.

[0073] The pressure control slide valve 140 is a mechanical valve. The oil inlet of the pressure control slide valve 140 is connected to the oil inlet of the clutch control valve 150, and the oil outlet of the pressure control slide valve 140 is connected to the electric motor 300. The pressure control slide valve 140 is used to control the system oil pressure at its oil inlet, that is, to control the pressure of the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, the oil inlet of the clutch control valve 150 and the oil inlet of the proportional solenoid valve 170.

[0074] The oil inlet of clutch control valve 150 communicates with the oil inlet of pressure control spool valve 140, and the oil outlet of clutch control valve 150 communicates with the vehicle's clutch 200. Clutch control valve 150 is used to control the engagement and disengagement of clutch 200. In this embodiment, clutch control valve 150 may be a solenoid valve. The vehicle's VCU is connected to clutch control valve 150, and the engagement and disengagement of clutch 200 are controlled through clutch control valve 150. In some embodiments, clutch control valve 150 may also be a pneumatic control valve or other suitable type of control valve.

[0075] The oil inlet of relief valve 180 is connected to the oil outlet of second oil pump 130, and the oil outlet of relief valve 180 is connected to the oil inlet of first oil pump 120 and the oil inlet of second oil pump 130. The feedback end of relief valve 180 is connected to the oil inlet of relief valve 180. The opening of relief valve 180 is positively correlated with the flow rate at the oil outlet of relief valve 180. That is, the greater the opening of relief valve 180, the greater the flow rate at the oil outlet of relief valve 180. The feedback end can control the opening of relief valve 180. Specifically, the greater the pressure at the feedback end (that is, the greater the pressure in the cooling and lubricating oil path between the feedback end, the oil inlet of relief valve 180, the oil outlet of second oil pump 130, the oil outlet of pressure control valve 140, and the motor 300), the greater the opening of relief valve 180. The pressure at the feedback port is determined by the oil viscosity of the cooling lubrication oil circuit (i.e., the viscosity of the oil). The pressure at the feedback port is positively correlated with the viscosity of the oil at the oil inlet of the relief valve 180. That is, the greater the oil viscosity, the greater the pressure at the feedback port. The oil viscosity is negatively correlated with temperature. That is, the lower the temperature, the greater the oil viscosity, and the higher the pressure at the feedback port. Conversely, the higher the temperature, the lower the oil viscosity, and the lower the pressure at the feedback port.

[0076] The oil inlet of proportional solenoid valve 170 is connected to the oil outlet of first oil pump 120. The oil outlet of proportional solenoid valve 170 is connected to the control port of pressure control spool 140 and the control port of relief spool 180. The greater the pressure at the control port, the greater the opening of relief spool 180. Proportional solenoid valve 170 is used to control the system oil pressure at the oil inlet of pressure control spool 140 and the opening of relief spool 180. In this embodiment, the vehicle's VCU is connected to proportional solenoid valve 170. By adjusting the current supplied to proportional solenoid valve 170, the pressure at the oil outlet of proportional solenoid valve 170 is controlled. Specifically, the pressure in the control oil circuit between the oil outlet of proportional solenoid valve 170, the control port of pressure control spool 140, and the control port of relief spool 180 is controlled. This, in turn, simultaneously controls the system oil pressure at the oil inlet of pressure control spool 140 and the opening of motor flow control spool 160. The greater the current supplied to proportional solenoid valve 170, the greater the pressure in the control oil circuit. This increases the system oil pressure at the oil inlet of pressure control spool valve 140 (a higher pressure threshold for opening pressure control spool valve 140 corresponds to a higher suction pressure). This increases the pressure at the control port of relief spool valve 180, and accordingly, the greater the opening of relief spool valve 180. Proportional solenoid valve 170 can be a pilot proportional solenoid valve 170 or another type of proportional solenoid valve 170, and those skilled in the art can select the appropriate type as needed.

[0077] In some embodiments, the hydraulic system further includes a cooling module, the oil inlet of which is in communication with the oil outlet of the second oil pump 130 and the oil outlet of the pressure control spool valve 140, for cooling the oil from the oil outlet of the second oil pump 130 and the oil outlet of the pressure control spool valve 140. The cooling module may include a pressure filter, an oil cooler, and a bypass differential pressure valve. The oil inlet of the oil cooler is in communication with the oil outlet of the second oil pump 130 via the pressure filter, and the oil outlet of the oil cooler is in communication with the electric motor 300. The bypass differential pressure valve's oil inlet is connected to the oil cooler's oil inlet via a pressure filter, while its oil outlet is connected to the oil cooler's oil outlet. The bypass differential pressure valve is designed to open when the pressure differential between the upstream and downstream sides of the oil cooler exceeds a set threshold. Upon opening, a portion of the oil is directed through the bypass differential pressure valve into the motor 300 (instead of passing through the oil cooler). However, the oil flow through the oil cooler is not reduced, nor is the oil cooler's heat dissipation efficiency compromised, thereby maintaining the maximum heat dissipation efficiency of the cooling lubricating oil circuit. In other embodiments, the bypass differential pressure valve's oil inlet may be directly connected to the oil cooler's oil inlet, opening when the pressure differential between the oil cooler's oil inlet and oil cooler's oil outlet exceeds a set threshold. In some embodiments, the cooling module may comprise only the oil cooler and the bypass differential pressure valve. The oil inlet of the relief valve 180 is connected to the cooling module's oil inlet; that is, the cooling module's oil inlet is connected to the feedback port of the relief valve 180.

[0078] When the vehicle is in series or parallel mode and in extremely cold conditions, the oil output from the first oil pump 120 passes through the pressure control valve 140 and enters the cooling and lubricating oil circuit between the feedback port of the relief valve 180, the oil inlet of the relief valve 180, the oil outlet of the second oil pump 130, the oil outlet of the pressure control valve 140, and the motor 300. At this point, the oil temperature in the cooling and lubricating oil circuit is extremely low, the oil viscosity is high, the pressure at the feedback port is high, and the opening of the relief valve 180 is wide. As a result, the majority of the oil output from the first oil pump 120 preferentially flows through the relief valve 180 back to the inlet of the first oil pump 120, rapidly circulating the oil in the fuel tank 110 and rapidly increasing its temperature. When the oil temperature rises to a certain value (e.g., above 30°C), the pressure at the feedback port decreases significantly, and the opening of the relief valve 180 automatically returns to its neutral position, allowing more oil to be distributed to the motor 300 for cooling and lubrication.

[0079] When the vehicle is in pure electric mode, motor 300 drives the wheels, requiring high cooling for motor 300. The engine is not operating, clutch 200 does not need to be engaged, first oil pump 120 is not operating, and second oil pump 130 is operating. The control port is essentially pressure-free, and the feedback port automatically feeds back the corresponding pressure to relief valve 180 based on the oil temperature. At low temperatures (e.g., below 30°C), the pressure at the feedback port is high, and relief valve 180 opens to a neutral position, diverting some unnecessary cooling flow to the inlet of second oil pump 130, allowing the oil to circulate rapidly and heat up. At high temperatures (e.g., above 30°C), the pressure at the feedback port is low, and relief valve 180 is closed or minimally opened, allowing all or nearly all of the cooling and lubricating oil flow to enter motor 300 for cooling and lubrication.

[0080] When the vehicle is in engine direct drive mode or parallel mode, the motor 300 is not operating or has low power, and the clutch 200 needs to engage. A larger current can be supplied to the proportional solenoid valve 170, causing it to open wider and the pressure in the control oil circuit to be higher. Consequently, the system oil pressure at the oil inlet of the control pressure control spool valve 140 is kept relatively high, and the control relief spool valve 180 is also kept at a relatively high opening. Consequently, the pressure in the pressure oil circuit is relatively high (with a relatively high upper pressure limit). Controlling the clutch control valve 150 ensures that the clutch 200 engages effectively without overpressure. Furthermore, the relief spool valve 180 can overflow a portion of the excess flow from the first and second oil pumps 120, 130, saving hydraulic energy.

[0081] When the vehicle is in parking power generation mode, the motor 300 is inoperative and requires no cooling, the clutch 200 does not need to be engaged, the first oil pump 120 is in operation, and the second oil pump 130 is inoperative. At this time, a high current can be supplied to the proportional solenoid valve 170, thereby controlling the overflow valve 180 to be fully opened. The overflow valve 180 overflows a portion of the excess flow from the first oil pump 120, saving hydraulic energy.

[0082] In other words, the overflow spool valve 180 in the hydraulic system 100' of this embodiment can achieve two-stage overflow. The first-stage overflow occurs primarily in low-temperature conditions, when the cooling flow demand of the vehicle's various systems is low. High engine speeds and high engine flow rates passively increase system flow resistance, reaching the overflow pressure point and opening the overflow valve, thereby reducing system pressure and energy consumption. The second-stage overflow occurs in parallel or direct-drive mode, when the cooling flow demand of the vehicle's various systems is lower than in series operation. The proportional solenoid valve 170 can be used to increase the opening of the two-stage overflow valves, thereby increasing the overflow flow of the overflow spool valve 180 and reducing system energy consumption. According to the hydraulic system 100' of this embodiment, a single proportional solenoid valve 170 simultaneously controls both the pressure control spool valve 140 and the overflow spool valve 180 in the hydraulic system 100' without adding additional solenoid valves, achieving regulation of the pressure circuit pressure limit and overflow flow. This simplifies control and reduces costs, resulting in low energy consumption for the hydraulic system 100'.

[0083] In some other embodiments, the vehicle may only have any one or more operating modes among pure electric mode, series mode, parallel mode, engine direct drive mode and parking power generation mode.

[0084] 3 , a hydraulic system 100 ″ of a vehicle according to the third embodiment of the present application is exemplarily described. The vehicle may be a hybrid vehicle. The hydraulic system 100 ″ includes an oil tank 110 , an oil pump unit, a pressure control slide valve 140 , a switch control slide valve 190 , a clutch control valve 150 and a proportional solenoid valve 170 .

[0085] The oil pump unit includes a first oil pump 120 and a second oil pump 130. The oil inlet of the first oil pump 120 is connected to the fuel tank 110, and the oil outlet of the first oil pump 120 is connected to the oil inlet of the pressure control spool valve 140, the oil inlet of the on / off control spool valve 190, and the oil inlet of the proportional solenoid valve 170. The oil inlet of the second oil pump 130 is connected to the fuel tank 110, and the oil outlet of the second oil pump 130 is connected to the oil outlet of the pressure control spool valve 140 and the vehicle's electric motor 300. The oil inlets of the first and second oil pumps 120, 130 can be connected to the fuel tank 110 via a suction filter, which filters the oil to reduce the risk of subsequent control valve sticking. In this embodiment, both the first oil pump 120 and the second oil pump 130 can be mechanical oil pumps. The first oil pump 120 is connected to the vehicle's engine at a specific speed ratio, while the second oil pump 130 is connected to the vehicle's wheel ends (e.g., the vehicle's differential) at a specific speed ratio. The oil pump unit also includes a one-way valve, the first end of which is connected to the oil inlet of the second oil pump 130, and the second end of which is connected to the oil outlet of the second oil pump 130. The flow direction of the one-way valve is from the first end to the second end of the one-way valve. When the vehicle is moving forward, the second oil pump 130 rotates forward to pump oil from the fuel tank 110 to the motor flow control spool valve 160. During this time, the one-way valve is closed. When the vehicle is reversing, the second oil pump 130 rotates backward. At this time, the one-way valve is opened, and the oil circulates through the second oil pump 130 and the one-way valve, reducing the resistance to reverse rotation of the second oil pump 130 and preventing backflow. In some other embodiments, the first oil pump 120 may be a mechanical oil pump, and the second oil pump 130 may be an electronic oil pump.

[0086] The oil inlet of the pressure control slide valve 140 is connected to the oil inlet of the clutch control valve 150, and the oil outlet of the pressure control slide valve 140 is connected to the electric motor 300. The pressure control slide valve 140 is used to control the pressure of the oil at its oil inlet, that is, to control the pressure of the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, the oil inlet of the switch control slide valve 190 and the oil inlet of the proportional solenoid valve 170.

[0087] The oil inlet of on-off control spool valve 190 communicates with the oil inlet of pressure control spool valve 140, while the oil outlet of on-off control spool valve 190 communicates with the oil inlet of clutch control valve 150. On-off control spool valve 190 can be opened and closed in a controlled manner. When on-off control spool valve 190 is open, oil from the pressure oil circuit can enter clutch control valve 150 and, subsequently, clutch 200. When on-off control spool valve 190 is closed, oil from the pressure oil circuit cannot enter clutch control valve 150 and, subsequently, clutch 200.

[0088] The oil inlet of clutch control valve 150 communicates with the oil inlet of pressure control spool valve 140, and the oil outlet of clutch control valve 150 communicates with the vehicle's clutch 200. Clutch control valve 150 is used to control the engagement and disengagement of clutch 200. In this embodiment, clutch control valve 150 may be a solenoid valve. The vehicle's VCU is connected to clutch control valve 150, and the engagement and disengagement of clutch 200 are controlled through clutch control valve 150. In some embodiments, clutch control valve 150 may also be a pneumatic control valve or other suitable type of control valve.

[0089] The oil inlet of proportional solenoid valve 170 is connected to the oil outlet of first oil pump 120, and the oil outlet of proportional solenoid valve 170 is connected to the control port of pressure control spool valve 140 and the control port of on-off control spool valve 190. Proportional solenoid valve 170 is used to control the system oil pressure at the oil inlet of pressure control spool valve 140 and the opening and closing of on-off control spool valve 190. In this embodiment, the vehicle's VCU is connected to proportional solenoid valve 170. By adjusting the current supplied to proportional solenoid valve 170, the pressure at the oil outlet of proportional solenoid valve 170 is controlled. In other words, the pressure in the control oil circuit between the oil outlet of proportional solenoid valve 170, the control port of pressure control spool valve 140, and the control port of on-off control spool valve 190 is controlled, thereby simultaneously controlling the system oil pressure at the oil inlet of pressure control spool valve 140 and the opening and closing of motor flow control spool valve 160. The greater the current supplied to proportional solenoid valve 170, the greater the pressure at the oil outlet of proportional solenoid valve 170, the greater the pressure in the control oil circuit, the greater the system oil pressure at the oil inlet of pressure control spool valve 140, and the greater the pressure in the pressure oil circuit. On-off control spool valve 190 opens when the pressure in the control oil circuit exceeds a certain threshold (and closes when the pressure is below the threshold). That is, when the pressure in the pressure oil circuit is low, on-off control spool valve 190 closes, and when the pressure in the pressure oil circuit is high, on-off control spool valve 190 opens. Proportional solenoid valve 170 can be a pilot proportional solenoid valve 170 or another type of proportional solenoid valve 170, and those skilled in the art can select the appropriate type as needed.

[0090] Currently, conventional hydraulic systems do not include a switch control slide valve 190. The clutch control valve 150 is connected to the pressure oil circuit (i.e., the oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, and the oil inlet of the clutch control valve 150). The wheel's VCU obtains the pressure of the pressure oil circuit through a pressure sensor and controls the clutch control valve 150 accordingly. The opening condition of the clutch control valve 150 is that the pressure value of the pressure oil circuit measured by the pressure sensor reaches a corresponding threshold. When the pressure of the pressure oil circuit is low, it can be considered that the clutch 200 does not need to engage at this time. However, if the pressure sensor fails and detects incorrectly at this time, the clutch control valve 150 will mistakenly believe that the opening condition has been met and control the clutch control valve 150 to open. This will cause some logical errors and pose a risk to driving safety.

[0091] In the hydraulic system 100 of this embodiment, the proportional solenoid valve 170 simultaneously controls the system oil pressure at the oil inlet of the pressure control spool valve 140 and the opening and closing of the on-off control spool valve 190. When the opening of the pressure control spool valve 140 is small and the pressure in the pressure oil circuit is low, the on-off control spool valve 190 is closed, and oil cannot enter the clutch control valve 150 through the on-off control spool valve 190. As a result, the clutch control valve 150 cannot control the engagement of the clutch 200. This effectively prevents erroneous engagement of the clutch 200 when a pressure sensor malfunctions. When the system oil pressure at the oil inlet of the pressure control spool valve 140 and the pressure in the pressure oil circuit are high, the on-off control spool valve 190 opens, allowing oil to enter the clutch control valve 150 through the on-off control spool valve 190. In this case, the clutch control valve 150 can normally control the engagement and disengagement of the clutch 200.

[0092] When the vehicle is in pure electric mode, electric motor 300 drives the wheels, requiring high cooling for electric motor 300. The engine is not operating, clutch 200 is not required to engage, first oil pump 120 is not operating, and second oil pump 130 is operating. In this situation, current is not supplied to proportional solenoid valve 170, maintaining a low pressure in the control oil circuit. Consequently, pressure control spool valve 140 is fully closed, and the system oil pressure at the oil inlet of pressure control spool valve 140 is at the first oil pressure. Simultaneously, switch control spool valve 190 is closed, preventing oil from the pressure oil circuit from entering clutch control valve 150, effectively preventing accidental engagement of clutch 200 when no engagement is required.

[0093] When the vehicle is in series mode, motor 300 drives the wheels, requiring high cooling for motor 300. The engine is operating, clutch 200 is not engaged, and both first and second oil pumps 120 and 130 are operating. In this situation, a low current can be supplied to proportional solenoid valve 170, causing it to open to its first position and the pressure in the control oil circuit to remain low. Consequently, pressure control spool valve 140 is controlled to be closed or open, and the system oil pressure at the oil inlet of pressure control spool valve 140 is controlled to be at a second pressure, which is greater than or equal to the first pressure. Simultaneously, on-off control spool valve 190 is controlled to be closed, preventing oil from the pressure oil circuit from entering clutch control valve 150, effectively preventing accidental engagement of clutch 200 when no engagement is required.

[0094] When the vehicle is in parallel mode, motor 300 and the engine jointly drive the wheels. Motor 300 requires less cooling, clutch 200 needs to be engaged, and both first and second oil pumps 120 and 130 are operating. In this situation, a higher current can be supplied to proportional solenoid valve 170, causing it to reach a second opening, which is greater than the first opening. This results in a higher pressure in the control oil circuit, exceeding the pressure threshold for opening on / off control spool valve 190. Consequently, pressure control spool valve 140 is open, and the system oil pressure at the oil inlet of pressure control spool valve 140 reaches a third pressure, which is greater than the second pressure. Simultaneously, on / off control spool valve 190 is also open. At this time, the pressure of the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, the oil inlet of the clutch control valve 150 and the oil inlet of the proportional solenoid valve 170 is relatively high (with a higher pressure upper limit), and then by controlling the clutch control valve 150, it can be ensured that the clutch 200 is effectively engaged and there is no overpressure.

[0095] When the vehicle is in engine direct drive mode, electric motor 300 is inoperative and requires little or no cooling. The engine drives the wheels, clutch 200 is engaged, and both first and second oil pumps 120 and 130 are in operation. In this situation, a high current can be supplied to proportional solenoid valve 170, causing it to reach a third opening degree (greater than the second opening degree). This results in a high pressure in the control oil circuit, exceeding the pressure threshold for opening on / off control spool valve 190. Consequently, pressure control spool valve 140 is open, and the system oil pressure at the oil inlet of pressure control spool valve 140 reaches a fourth pressure (greater than the third pressure). Simultaneously, on / off control spool valve 190 is also open. At this time, the pressure of the pressure oil circuit between the oil outlet of the first oil pump 120, the oil inlet of the pressure control slide valve 140, the oil inlet of the clutch control valve 150 and the oil inlet of the proportional solenoid valve 170 is relatively high (with a higher pressure upper limit), and then by controlling the clutch control valve 150, it can be ensured that the clutch 200 is effectively engaged and there is no overpressure.

[0096] When the vehicle is in parking power generation mode, the engine operates to drive the generator to generate electricity, while the motor 300 is inoperative and does not require cooling. The clutch 200 does not need to be engaged, the first oil pump 120 operates, and the second oil pump 130 does not operate. At this time, a large current can be supplied to the proportional solenoid valve 170, causing it to be in the fourth opening degree (which is greater than the third opening degree). The pressure in the control pressure oil circuit is at a high level, exceeding the pressure threshold for opening the on / off control spool 190. Consequently, the system oil pressure at the oil inlet of the control pressure control spool 140 is at the fifth oil pressure, which is greater than the fourth oil pressure. Simultaneously, the on / off control spool 190 is controlled to be in the open state.

[0097] The hydraulic system 100" of this embodiment, without adding more solenoid valves, simultaneously controls the pressure control slide valve 140 and the switch control slide valve 190 in the hydraulic system 100" through a single proportional solenoid valve 170, thereby achieving the adjustment of the upper pressure limit of the pressure oil circuit and the adjustment of the oil entering the clutch control valve 150, which can effectively prevent the clutch 200 from being engaged incorrectly when there is no engagement demand, avoiding the system safety problems caused by this.

[0098] In some other embodiments, the vehicle may only have any one or more operating modes among the pure electric mode, series mode, parallel mode, engine direct drive mode and parking power generation mode.

[0099] With reference to FIG4 , the hydraulic system of a vehicle according to the fourth embodiment of the present application is exemplarily described. The vehicle may be a hybrid vehicle. The hydraulic system includes an oil tank 35 , an oil pump unit, a pressure control slide valve 4 , a switch control slide valve 7 , a clutch control valve 11 , a motor flow control slide valve 24 , an overflow slide valve 21 and a proportional solenoid valve 3 .

[0100] The oil pump unit includes a first oil pump 1 and a second oil pump 18. The oil inlet of the first oil pump 1 is connected to the oil tank 35 through a suction filter 36. The oil outlet of the first oil pump 1 is connected to the oil inlet P2 of the pressure control slide valve 4, the oil inlet P3 of the on / off control slide valve 7, and the oil inlet P1 of the proportional solenoid valve 3 via a pressure oil circuit L1. A pressure filter 2 is provided on pressure oil circuit L1. The oil inlet of the pressure filter 2 is connected to the oil outlet of the first oil pump 1, and the oil outlet of the pressure filter 2 is connected to the oil inlet P2 of the pressure control slide valve 4, the oil inlet P3 of the on / off control slide valve 7, and the oil inlet P1 of the proportional solenoid valve 3. The pressure filter 2 is used to improve filtration accuracy and reduce the risk of subsequent slide valves and solenoid valves sticking. The oil inlet of the second oil pump 18 is connected to the oil tank 35 through a suction filter 36. The oil outlet of the second oil pump 18 is connected to the oil outlet A2 of the pressure control slide valve 4 and the oil inlet P9 of the flow control valve via a cooling and lubricating oil line L2. Both the first oil pump 1 and the second oil pump 18 are mechanical oil pumps. The first oil pump 1 is connected to the vehicle's engine 29 at a specific speed ratio, while the second oil pump 18 is connected to the vehicle's wheel end (e.g., the vehicle's differential) at a specific speed ratio. The oil pump unit also includes a one-way valve, the first end of which is connected to the oil inlet of the second oil pump 18 and the second end of which is connected to the oil outlet of the second oil pump 18. The oil flow direction of the one-way valve is from the first end to the second end of the one-way valve. When the vehicle is moving forward, the second oil pump 18 rotates forward to pump oil from the oil tank 15 to the motor flow control slide valve 24. At this time, the one-way valve is closed. When the vehicle is reversing, the second oil pump 18 rotates backward. At this time, the one-way valve is opened, and the oil circulates through the second oil pump 18 and the one-way valve, reducing the reverse resistance of the second oil pump 18 and preventing backflow. In other embodiments, the first oil pump 1 can be a mechanical oil pump, and the second oil pump 18 can be an electronic oil pump.

[0101] The oil outlet A4 of the on-off control valve communicates with the oil inlet P4 of the clutch control valve 11, while the oil outlet A7 of the clutch control valve 11 communicates with the clutch. The oil outlet A11 of the motor flow control spool 24 communicates with the vehicle's electric motor 31. The oil inlet P6 of the relief spool 21 communicates with the oil outlet of the second oil pump 18. The oil outlet A8 of the relief spool 21 communicates with the oil inlets of the first oil pump 1 and the second oil pump 18. The feedback port C8 of the relief spool 21 communicates with the oil inlet P6 of the relief spool 21. The oil outlet A1 of the proportional solenoid valve 3 communicates with the control port C1 of the pressure control spool 4, the control port C3 of the on-off control spool 7, the control port C9 of the motor flow control spool 24, and the control port C7 of the relief spool 21 via a control oil passage L3. The proportional solenoid valve 3 is used to simultaneously control the system oil pressure at the oil inlet of the pressure control spool 4, the opening and closing of the on-off control spool 7, the opening of the motor flow control spool 24, and the opening of the relief spool 21. The greater the current supplied to the proportional solenoid valve 3, the greater the pressure in the control oil circuit L3. Accordingly, the greater the system oil pressure at the oil inlet of the pressure control spool 4, the smaller the opening of the motor flow control spool 24, and the larger the opening of the relief spool 21. The on-off control spool 7 closes when the pressure in the control oil circuit L3 is less than a set threshold and opens when the pressure in the control oil circuit L3 is greater than or equal to the set threshold. The specific methods for controlling the pressure control spool 4, the on-off control spool 7, the motor flow control spool 24, and the relief spool 21 via the proportional solenoid valve 3 can be found in the first to third embodiments described above and will not be repeated here.

[0102] In this embodiment, the hydraulic system also includes a shift solenoid valve 10. Its oil inlet P5 is connected to the oil outlet A4 of the on / off control spool valve 7. Its working oil port is also connected to the vehicle's shift unit, and the shift solenoid valve 10 is used to control the shift unit's shifting. Specifically, the shift unit includes a first-gear piston 15 and a second-gear piston 16. The shift solenoid valve 10's working oil port A6 is connected to the first-gear piston 15, while the shift solenoid valve 10's working oil port A5 is connected to the second-gear piston 16. The shift solenoid valve 10 can controllably change the direction of oil flow in ports A6 and A5. When oil flows out of port A6 and flows into port A5, the oil pushes the first piston toward the second piston. When oil flows into port A6 and flows out of port A5, the oil pushes the second piston toward the first piston, thereby controlling the speed reducer 32 to shift gears. The shift unit also includes a gear position sensor 17, which is used to monitor the gear position signal. The vehicle's VCU can be connected to the gear position sensor 17 and the shift solenoid valve 10 to obtain the gear position signal from the gear position sensor 17 and control the shift solenoid valve 10 to drive the first gear piston 15 and the second gear piston 16 to shift gears.

[0103] In this embodiment, the oil return port T1 of the switch control solenoid valve, the oil return port T2 of the clutch control valve 11, and the oil return port T3 of the shift solenoid valve 10 are connected to the oil inlet of the first oil pump 1 via a return oil line L4. The pressure oil line L1 is connected to the return oil line L4 via a safety valve 6, with the flow of oil from the pressure oil line L1 to the return oil line L4. The safety valve 6 opens when the pressure in the pressure oil line L1 exceeds a set threshold (it closes otherwise), causing overflow oil to flow back through the return oil line L4 to the oil inlets of the first and second oil pumps 18. In this embodiment, a pressure sensor 5 is installed in the pressure oil line L1 to monitor the pressure in the pressure oil line L1. The vehicle's VCU is connected to the pressure sensor 5 and the clutch control valve 11. The pressure in the pressure oil line L1 is detected by the pressure sensor 5 and the clutch control valve 11 is controlled based on the pressure in the pressure oil line L1 to engage or disengage the clutch 30.

[0104] In this embodiment, a buffer 14, a damping orifice 40, and a damping orifice 41 are provided in the oil circuit between the oil outlet A7 of the clutch control valve 11 and the clutch 30. These buffers 14, damping orifice 40, and damping orifice 41 are used to reduce pressure fluctuations. The hydraulic system also includes a one-way valve 12. The first end of the one-way valve 12 is connected to the oil outlet A7 of the clutch control valve 11, and the second end is connected to the oil inlet P4 of the clutch control valve 11. The flow direction of the one-way valve 12 is from the first end to the second end. The function of the one-way valve 12 is functional safety, preventing the clutch control valve 11 from sticking, which could result in the clutch 30 not being able to properly release pressure. A pressure sensor 13 is provided in the oil circuit between the first end of the one-way valve 12 and the oil outlet A7 of the clutch control valve 11. This pressure sensor 13 is used to detect clutch control pressure. The vehicle's VCU is connected to the pressure sensor 13 to obtain the clutch control pressure.

[0105] In this embodiment, the vehicle's clutch 30, bearing 27, and generator 28 are all connected to the cooling lubricating oil circuit L2. Oil from the cooling lubricating oil circuit L2 can enter the clutch 30, bearing 27, and generator 28 to lubricate and cool them. The hydraulic system also includes a cooling module. The cooling module's oil inlet is connected to the oil outlet of the second oil pump 18 and the oil outlet A2 of the pressure control slide valve 4. The cooling module's oil outlet is connected to the motor 31, clutch 30, bearing 27, and generator 28. The cooling module is used to cool the oil. The cooling module includes a pressure filter 19, an oil cooler 20 and a bypass pressure differential valve 22 located on the cooling lubricating oil circuit L2. The oil inlet of the oil cooler 20 is connected to the oil outlet of the second oil pump 18 through the pressure filter 19. The oil outlet of the oil cooler 20 is connected to the oil inlet P9 of the motor flow control slide valve 24, the clutch 30, the generator 28 and the vehicle's bearing 27. The oil cooler 20 is used to cool the oil input to the motor 31, the clutch 30, the bearing 27 and the generator 28 to improve the cooling effect of the oil. The bypass pressure differential valve 22's oil inlet P7 is connected to the oil inlet of the oil cooler 20 through the pressure filter 19, and its oil outlet A9 is connected to the oil outlet of the oil cooler 20. The bypass pressure differential valve 22 is designed to open when the pressure differential between the upstream and downstream sides of the oil cooler 20 exceeds a set threshold. Once opened, a portion of the oil is transferred through the bypass pressure differential valve 22 to the motor 31, clutch 30, bearing 27, and generator 28 (rather than through the oil cooler). However, the flow rate of the oil through the oil cooler is not reduced, nor is the heat dissipation efficiency of the oil cooler reduced. Thus, the heat dissipation efficiency of the cooling lubricating oil circuit can be maintained at a maximum. In other embodiments, the bypass pressure differential valve 22's oil inlet P7 can be directly connected to the oil cooler's oil inlet, so that it opens when the pressure differential between the oil inlet and oil outlet of the oil cooler 20 exceeds a set threshold. In other embodiments, the cooling module may only include the oil cooler 20 and the bypass pressure differential valve 22.

[0106] In this embodiment, the hydraulic system also includes a clutch flow control valve 26 and a differential pressure check valve 25 located in the cooling lubricating oil circuit. The clutch flow control valve 26's oil inlet is connected to the oil outlet of the oil cooler 20, while its oil outlet is connected to the clutch. The inlet P8 of the differential pressure check valve 25 is connected to the clutch flow control valve 26's oil inlet, while the outlet A10 of the differential pressure check valve 25 is connected to the clutch flow control valve 26's oil outlet. The differential pressure check valve 25 is used to maintain a constant differential pressure between the clutch flow control valve 26's oil inlet and outlet, i.e., to a specific value or a very small range of variation. According to the following formula: Q = C*A*√(Δp / 2ρ) (where Q is the flow rate, C is the coefficient, A is the flow channel cross-sectional area, Δp is the pressure difference, and ρ is the oil density), when the pressure difference is constant, the flow rate Q is directly linearly related to the flow channel cross-sectional area A, and therefore linearly related to the opening of the control valve in the flow channel. Thus, the setting of the pressure differential one-way valve 25 can keep the pressure difference between the inlet and outlet of the clutch flow control valve 26 constant. As long as the opening of the clutch flow control valve 26 is adjusted, the cooling flow entering the clutch 30 can be linearly adjusted. The VCU of the vehicle. At present, the cooling flow entering the clutch in conventional hydraulic systems is usually not adjustable. Under low temperature conditions and when the vehicle is in parking power generation mode, the cooling flow demand of the clutch is very low or there is no demand. A lot of unnecessary flow passes through the clutch, causing energy loss of the hydraulic system and also causing large oil stirring loss to the clutch. The hydraulic system of the present application can linearly adjust the flow entering the clutch 30 according to the cooling flow demand of the clutch 30, which can effectively reduce the energy loss of the hydraulic system and reduce the oil stirring loss.

[0107] In this embodiment, the hydraulic system also includes a buffer 8, which is connected to the oil outlet A1 of the proportional solenoid valve 3. A damping orifice 49 is provided in the oil path between the buffer 8 and the oil outlet A1 of the proportional solenoid valve 3. Damping orifices 38, 39, 45, and 44 are provided on the control oil circuit L3 near the control port C1 of the pressure control spool valve 4, the control port C3 of the on-off control spool valve 7, the control port C9 of the motor flow control spool valve 24, and the control port C7 of the relief spool valve 21, respectively. The buffer 8, damping orifice 49, 38, 39, 45, and 44 are used to reduce pressure fluctuations in the control oil circuit L3. A damping orifice 37 is provided on the pressure oil circuit L1 near the oil inlet P1 of the proportional solenoid valve 3 to reduce pressure fluctuations in the pressure oil circuit L1. Damping holes 46, 47, 43 and 48 are respectively provided on the cooling and lubricating oil circuit L2 near the motor 31, the clutch 30, the bearing 27 and the generator 28. A damping hole 42 is also provided on the cooling and lubricating oil circuit L2. The damping holes 46, 47, 43, 48 and 42 are used to reduce the pressure fluctuations of the cooling and lubricating oil circuit L2. The cooling lubricating oil circuit L2 is also equipped with a check valve 9 and a check valve 23. The first end of the check valve 9 is connected to the oil outlet A2 of the pressure control slide valve 4, and the second end of the check valve 9 is connected to the oil outlet of the second oil pump 18. The flow direction of the check valve 9 is from its first end to its second end. The first end of the check valve 23 is connected to the oil outlet of the oil cooler 20, and the second end of the check valve 23 is connected to the oil inlet P9 of the flow control valve, the oil inlet of the clutch flow control valve 26, the bearing 27, and the generator 28. The flow direction of the check valve 23 is from its first end to its second end. The check valves 9 and 23 are used to prevent oil backflow.

[0108] In some other embodiments, one of the switch control slide valve 7, the motor flow control slide valve 24, and the overflow slide valve 21 can be replaced by a solenoid valve, which is directly controlled by the vehicle's VCU. The proportional solenoid valve 3 jointly controls the remaining two of the switch control slide valve 7, the motor flow control slide valve 24, the overflow slide valve 21 and the pressure control slide valve 4. The specific control method can refer to the first to third embodiments mentioned above, and will not be repeated here.

[0109] The present application also provides a vehicle comprising the hydraulic system of the above embodiment. The vehicle may be a hybrid vehicle capable of switching between a pure electric mode, a series mode, a parallel mode, an engine direct drive mode, and a parking power generation mode.

[0110] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0111] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0112] Similarly, it should be understood that in order to streamline the present application and aid in understanding one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this approach of the present application should not be interpreted as reflecting the intention that the application claimed for protection requires more features than those explicitly recited in each claim. More precisely, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with fewer features than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present application.

[0113] Those skilled in the art will understand that, except where mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus disclosed herein may be combined in any combination. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0114] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

[0115] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims.

Claims

1. A hydraulic system for a vehicle, characterized in that: The hydraulic system (100) comprises: Proportional solenoid valve (170); a pressure control spool valve (140); and Target mechanical valve group; Wherein, the pressure control slide valve (140) is a mechanical valve, and the target mechanical valve group comprises: at least one mechanical valve; The hydraulic system (100) is configured to control the pressure control spool valve (140) and the target mechanical valve group by controlling the proportional solenoid valve (170).

2. The hydraulic system according to claim 1, characterized in that: The target mechanical valve group includes at least one of a motor flow control slide valve (160), a relief slide valve (180) and a switch control slide valve (190), wherein the motor flow control slide valve (160), the relief slide valve (180) and the switch control slide valve (190) are all mechanical valves.

3. The hydraulic system according to claim 2, characterized in that: The pressure of the oil outlet of the proportional solenoid valve (170) and the system oil pressure of the oil inlet of the pressure control slide valve (140) cooperate to regulate the opening of the pressure control slide valve (140); The pressure at the oil outlet of the proportional solenoid valve (170) and the oil pressure at the oil inlet of the motor flow control slide valve (160) regulate the opening of the motor flow control slide valve (160); The pressure of the oil outlet of the proportional solenoid valve (170) and the pressure of the feedback end of the overflow slide valve (180) cooperate to regulate the overflow opening of the overflow slide valve (180); The opening and closing of the switch control slide valve (190) is related to the pressure of the oil outlet of the proportional solenoid valve (170), wherein the switch control slide valve (190) is configured to open when the pressure of the oil outlet of the proportional solenoid valve (170) is greater than or equal to a set threshold, and to close when the pressure of the oil outlet of the proportional solenoid valve (170) is less than the set threshold.

4. The hydraulic system according to any one of claims 2 or 3, characterized in that: The vehicle comprises a fuel tank (110) and a first fuel pump (120); The oil outlet of the first oil pump (120) is respectively connected to the oil inlet of the proportional solenoid valve (170) and the oil inlet of the pressure control slide valve (140); The oil inlet of the motor flow control slide valve (160) is in communication with the oil outlet of the pressure control slide valve (140), the oil outlet of the motor flow control slide valve (160) is in communication with the motor of the vehicle, and the control port of the motor flow control slide valve (160) is in communication with the proportional solenoid valve (170). The oil outlet is connected; The oil inlet of the overflow slide valve (180) is communicated with the oil outlet of the pressure control slide valve (140), the oil outlet of the overflow slide valve (180) is communicated with the oil inlet of the first oil pump (120), the control port of the overflow slide valve (180) is communicated with the oil outlet of the proportional solenoid valve (170), and the feedback end of the overflow slide valve (180) is communicated with the oil inlet of the overflow slide valve (180); The oil inlet of the switch control slide valve (190) is communicated with the oil inlet of the pressure control slide valve (140), the oil outlet of the switch control slide valve (190) is communicated with the oil inlet of the clutch control valve (150) of the vehicle, and the control port of the switch control slide valve (190) is communicated with the oil outlet of the proportional solenoid valve (170).

5. The hydraulic system according to claim 4, characterized in that: The hydraulic system (100) further includes a second oil pump and a cooling module; The oil inlet of the second oil pump is in communication with the oil tank (110), and the oil outlet of the second oil pump and the oil outlet of the pressure control slide valve (140) are both in communication with the oil inlet of the cooling module; The oil outlet of the cooling module is in communication with the oil inlet of the motor flow control slide valve (160).

6. The hydraulic system according to claim 5, characterized in that: The first oil pump (120) and the second oil pump are both mechanical oil pumps, the first oil pump (120) is connected to the engine of the vehicle, and the second oil pump is connected to the wheel end of the vehicle; The vehicle also includes a one-way valve, a first end of the one-way valve is connected to the oil inlet of the second oil pump, a second end of the one-way valve is connected to the oil outlet of the second oil pump, and a flow direction of the one-way valve is from the first end of the one-way valve to the second end of the one-way valve.

7. The hydraulic system according to any one of claims 5 or 6, characterized in that: When the vehicle is in the first working mode, the first oil pump (120) does not work, and the second oil pump works, and the proportional solenoid valve (170) is controlled to be in a closed state, so as to control the system oil pressure of the oil inlet of the pressure control slide valve (140) to be in a first oil pressure, control the motor flow control slide valve (160) to be in a fully open state, and control the switch control slide valve (190) to be in a closed state, wherein the control port of the overflow slide valve (180) has no pressure, and the overflow slide valve (180) is opened or closed according to the pressure of the feedback end; and / or, When the vehicle is in the second working mode, the first oil pump (120) is in operation, the second oil pump is in operation, and the proportional solenoid valve (170) is controlled to be in a first opening degree, so as to control the system oil pressure of the oil inlet of the pressure control slide valve (140) to be in a second oil pressure, control the motor flow control slide valve (160) to be in a first opening state, and control the overflow slide valve (180) to be in an open state. and controlling the switch control slide valve (190) to be in a closed state; and / or, When the vehicle is in the third working mode, the first oil pump (120) is working, the second oil pump is working, and the proportional solenoid valve (170) is controlled to be in the second opening degree, so as to control the system oil pressure of the oil inlet of the pressure control slide valve (140) to be in the third oil pressure, control the motor flow control slide valve (160) to be in the second opening state, control the overflow slide valve (180) to be in the open state, and control the switch control slide valve (190) to be in the open state; and / or, When the vehicle is in the fourth working mode, the first oil pump (120) is working, the second oil pump is working, and the proportional solenoid valve (170) is controlled to be in a third opening degree, so as to control the system oil pressure of the oil inlet of the pressure control slide valve (140) to be in a fourth oil pressure, control the motor flow control slide valve (160) to be in a third open state or a closed state, control the overflow slide valve (180) to be in an open state, and control the switch control slide valve (190) to be in an open state; and / or, When the vehicle is in the fifth working mode, the first oil pump (120) is working, the second oil pump is not working, and the proportional solenoid valve (170) is controlled to be in a fourth opening, so as to control the system oil pressure of the oil inlet of the pressure control slide valve (140) to be in a fifth oil pressure, control the motor flow control slide valve (160) to be in a closed state, control the overflow slide valve (180) to be in an open state, and control the switch control slide valve (190) to be in an open state.

8. The hydraulic system according to claim 7, characterized in that: The first opening is smaller than the second opening, the second opening is smaller than the third opening, and the third opening is smaller than the fourth opening; The first oil pressure is less than or equal to the second oil pressure, the second oil pressure is less than the third oil pressure, the third oil pressure is less than the fourth oil pressure, and the fourth oil pressure is less than the fifth oil pressure; The opening degree in the first open state is less than or equal to the opening degree in the fully open state, the opening degree in the second open state is less than the opening degree in the first open state, and the opening degree in the third open state is less than the opening degree in the second open state.

9. The hydraulic system according to any one of claims 7 or 8, characterized in that: The first working mode is a pure electric mode, the second working mode is a series mode, the third working mode is a parallel mode, the fourth working mode is an engine direct drive mode, and the fifth working mode is a parking power generation mode.

10. The hydraulic system according to any one of claims 5 to 9, characterized in that: The feedback end of the overflow slide valve (180) is in communication with the oil inlet of the cooling module, and the pressure of the feedback end is positively correlated with the oil viscosity characteristic of the oil at the oil inlet of the cooling module.

11. The hydraulic system according to any one of claims 5 to 10, characterized in that: The oil viscosity characteristic of the oil at the oil inlet of the cooling module is negatively correlated with the temperature of the oil.

12. The hydraulic system according to any one of claims 6 to 11, characterized in that: The hydraulic system (100) further comprises a shift solenoid valve; The oil inlet of the shift solenoid valve is communicated with the oil outlet of the switch control slide valve (190), the working oil port of the shift solenoid valve is communicated with the shift unit of the vehicle, and the shift solenoid valve is used to control the shift unit to shift gears.

13. The hydraulic system according to any one of claims 6 to 11, characterized in that: The cooling module includes an oil cooler and a bypass pressure differential valve; The oil inlet of the oil cooler is in communication with the oil outlet of the second oil pump, and the oil outlet of the oil cooler is in communication with the oil inlet of the motor flow control slide valve (160); The oil inlet of the bypass pressure differential valve is connected to the oil inlet of the oil cooler, and the oil outlet of the bypass pressure differential valve is connected to the oil outlet of the oil cooler. The bypass pressure differential valve is used to open when the pressure difference between the oil inlet of the oil cooler and the oil outlet of the oil cooler exceeds a set threshold.

14. The hydraulic system according to any one of claims 6 to 11, characterized in that: The hydraulic system (100) further comprises a clutch flow control valve and a differential pressure check valve; The oil inlet of the clutch flow control valve is communicated with the oil outlet of the cooling module, and the oil outlet of the clutch flow control valve is communicated with the clutch (200); The inlet of the pressure differential one-way valve is connected to the oil inlet of the clutch flow control valve, and the outlet of the pressure differential one-way valve is connected to the oil outlet of the clutch flow control valve. The pressure differential one-way valve is used to keep the pressure difference between the oil inlet of the clutch flow control valve and the oil outlet of the clutch flow control valve constant.

15. A vehicle, characterized in that: Comprising the hydraulic system (100) according to any one of claims 1-14.

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