Hybrid vehicle hydraulic system and control method thereof

Abstract

The invention relates to a hybrid vehicle hydraulic system and a control method thereof.The hybrid vehicle hydraulic system comprises an oil supply main pipeline, an oil supply pump, a hydraulic motor and a regulation and control motor, and the oil supply main pipeline is connected with an oil storage unit and a cooling and lubricating system of a hybrid vehicle; the oil supply pump is arranged on the upstream of the oil supply main pipeline, the power input end of the oil supply pump is connected with an engine of the hybrid vehicle, the engine drives the oil supply pump to start when running, and oil is pumped to the cooling and lubricating system from the oil storage unit; the hydraulic motor is arranged at the downstream of the oil supply main pipeline; an output shaft of the regulation and control motor is connected with a connecting shaft of the hydraulic motor; wherein the regulation and control motor is used for executing a corresponding control mode according to whether the engine runs or not. By adopting the scheme of the invention, the problem of resource waste in the prior art can be improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a hybrid vehicle hydraulic system and a control method thereof. Background Art

[0002] Hybrid vehicles utilize both an engine and an electric motor, achieving efficient energy utilization through oil-electric synergy. Hybrid vehicles utilize a fuel pump as the fuel source, which supplies excess oil after clutch actuation to the cooling and lubrication system. The pump is powered by the engine to which it is connected. An additional line to the cooling and lubrication system is also required, along with an electronic pump to provide high-pressure oil to the system when the engine is stopped.

[0003] In the related art, the electronic pump only provides the oil supply function when the engine is stopped, which is not fully utilized and there is a problem of resource waste. Summary of the Invention

[0004] Based on this, a hybrid vehicle hydraulic system and a control method thereof are provided to improve the problem of resource waste in the prior art.

[0005] In one aspect, a hybrid vehicle hydraulic system is provided, comprising:

[0006] an oil supply main line connecting the oil storage unit and a cooling and lubrication system of the hybrid vehicle;

[0007] an oil supply pump, disposed upstream of the oil supply main line, wherein a power input end of the oil supply pump is connected to the engine of the hybrid vehicle, and when the engine is running, the oil supply pump is driven to start and pump oil from the oil storage unit to the cooling and lubrication system;

[0008] a hydraulic motor, disposed downstream of the main oil supply line;

[0009] A regulating motor, wherein the output shaft of the regulating motor is connected to the connecting shaft of the hydraulic motor;

[0010] The regulating motor is used to execute a corresponding control mode according to whether the engine is running. The corresponding control mode includes a power generation control mode and / or a flow monitoring mode when the engine is running, and an oil pumping control mode when the engine is stopped.

[0011] In one embodiment, it further includes:

[0012] a system pressure control valve, the system pressure control valve being arranged on the oil supply main line between the hydraulic motor and the oil supply pump;

[0013] a bypass line connecting the oil storage unit and an inlet of the hydraulic motor;

[0014] A motor oil suction reversing valve is provided on the bypass pipeline.

[0015] In one embodiment, the system pressure control valve and the motor oil suction reversing valve are both provided with a hydraulic sensing chamber and a pressure balancing chamber, a sliding valve core is provided between the hydraulic sensing chamber and the pressure balancing chamber, the hydraulic sensing chambers of the system pressure control valve and the motor oil suction reversing valve are both connected to the outlet of the oil supply pump, and a force balancing element is provided in the pressure balancing chamber; when the thrust of the hydraulic sensing chamber is greater than the thrust of the pressure balancing chamber, the sliding valve core slides to open the system pressure control valve and close the motor oil suction reversing valve.

[0016] In one embodiment, it further includes:

[0017] A clutch pressure switching valve, wherein the outlet of the clutch pressure switching valve is connected to the hydraulic clutch and the inlet is connected to the outlet of the oil supply pump. The hydraulic clutch is a clutch between the engine and the wheel end;

[0018] The outlet of the clutch pressure switching valve is also connected to the pressure balance chamber of the system pressure control valve.

[0019] In one embodiment, it further includes:

[0020] a pressure sensor, the pressure sensor being arranged at the inlet of the hydraulic motor;

[0021] a motor controller connected to the regulating motor and the pressure sensor, and configured to control the regulating motor to execute a corresponding control mode according to whether the engine is running;

[0022] A vehicle controller is connected to the motor controller and is used to determine whether the engine of the hybrid vehicle is running.

[0023] In one embodiment, the oil supply pump is a variable displacement pump.

[0024] In another aspect, a control method for a hybrid vehicle hydraulic system is provided, which is applied to the hybrid vehicle hydraulic system, comprising:

[0025] Obtain the engine status of the hybrid vehicle and determine whether the engine is running;

[0026] Depending on whether the engine is running, the control motor is controlled to execute a corresponding control mode, including controlling the control motor to operate in a power generation control mode and / or a flow monitoring mode when the engine is running, or controlling the control motor to operate in an oil pumping control mode when the engine is stopped.

[0027] In one embodiment, controlling the regulating motor to operate in a power generation control mode and / or a flow monitoring mode includes:

[0028] In the power generation control mode, obtaining the inlet pressure of the hydraulic motor;

[0029] According to the deviation between the inlet pressure and the target pressure, the generating torque of the regulating motor is controlled so that the inlet pressure is consistent with the target pressure, wherein the target pressure is determined according to a preset system pressure and a preset pressure drop of the oil supply main line.

[0030] In one embodiment, controlling the regulating motor to operate in a power generation control mode and / or a flow monitoring mode includes:

[0031] In the flow monitoring mode, obtaining the rotational speed of the control motor;

[0032] The actual flow rate flowing through the hydraulic motor is obtained according to the rotation speed of the control motor and the displacement of the hydraulic motor.

[0033] In one embodiment, the fuel supply pump is a variable displacement pump, and after determining whether the engine is running, the method further includes:

[0034] When the engine is running, obtaining an actual flow rate flowing through the hydraulic motor, wherein the actual flow rate is obtained according to the rotation speed of the control motor and the displacement of the hydraulic motor;

[0035] According to the deviation between the actual flow rate and the target flow rate, the displacement of the oil supply pump is controlled to make the actual flow rate consistent with the target flow rate, wherein the target flow rate is determined according to the required flow rate of the cooling and lubrication system.

[0036] The above-mentioned hybrid vehicle hydraulic system and control method thereof connect the oil storage unit and the cooling and lubrication system of the hybrid vehicle through an oil supply main line, and an oil supply pump is arranged upstream of the oil supply main line. The oil supply pump is powered by the engine and starts and stops synchronously with the engine. When the engine is running, it can pump oil to the cooling and lubrication system. In addition, a hydraulic motor is arranged downstream of the oil supply main line, and a control motor is arranged to be connected to the hydraulic motor. When the engine is running, the oil supply pump serves as the oil supply source, and the hydraulic motor can rotate under the action of the oil, and the control motor executes the power generation mode or the flow monitoring mode, thereby playing a role during the operation of the engine; in addition, when the engine is stopped, the control motor can execute the oil pumping control mode, driving the hydraulic motor to perform the oil pumping function, giving full play to the role of the motor and the hydraulic motor, reducing the idleness of components, and effectively utilizing resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of power transmission in the engine direct drive mode;

[0038] Figure 2 This is a schematic diagram of power transmission in extended range mode;

[0039] Figure 3 This is a schematic diagram of power transmission in pure electric mode;

[0040] Figure 4 Schematic diagram of the structure of the hydraulic system of a hybrid vehicle;

[0041] Figure 5 A schematic diagram of the hybrid vehicle hydraulic system in engine direct drive mode;

[0042] Figure 6 A schematic diagram of the hybrid vehicle hydraulic system in range-extended mode;

[0043] Figure 7 A schematic diagram of the hybrid vehicle hydraulic system in pure electric mode;

[0044] Figure 8 The figure is a schematic diagram of the control flow of a hybrid vehicle hydraulic system according to an embodiment.

[0045] Reference numerals:

[0046] Oil supply main line 1, oil supply pump 2, hydraulic motor 3, control motor 4, system pressure control valve 5, bypass line 6, motor oil suction reversing valve 7, clutch pressure switching valve 8, hydraulic clutch 9, pressure sensor 10, motor controller 11, vehicle controller 12. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] Hybrid vehicles typically combine an engine (gasoline / diesel) and an electric motor, working together through an intelligent control system to improve efficiency and reduce emissions. Based on the powertrain structure, they can be categorized as series hybrid, parallel hybrid, and hybrid-parallel hybrid. In a series hybrid, the engine only drives the generator to generate electricity, which is then fed into the electric motor to drive the wheels, without directly participating in mechanical drive. In a parallel hybrid, both the engine and the electric motor can drive the wheels independently or together, with power coupling achieved through a gearbox. A hybrid-parallel hybrid combines series and parallel structures, distributing power through planetary gear sets or clutches, allowing for flexible switching between modes.

[0049] Hybrid vehicle operating modes can be summarized as engine direct drive mode, extended range mode, or pure electric mode, depending on the power source. In engine direct drive mode, the engine directly drives the wheels; in extended range mode, the engine drives the generator to generate electricity, which is then supplied to the electric motor to drive the wheels; in pure electric mode, the engine is turned off, and the electric motor uses the electricity stored in the battery and other energy storage components to drive the vehicle.

[0050] For example, Figures 1 to 3 The hybrid structure shown illustrates the working process of a hybrid vehicle.

[0051] The P1 motor acts as a generator, and the P3 motor acts as an electric motor. The P1 motor and the engine are coupled via a gear train. The P3 motor is connected to the wheel ends, and the wheel ends and the engine are connected via a clutch to transmit or isolate power. The clutch is typically a hydraulic clutch, and the clutch's oil chamber is selectively filled with oil via a control valve to achieve power coupling. The engine is also connected to an oil pump via a gear train. The oil pump is typically a mechanical pump. The oil pump pressurizes the cooling and lubricating oil, and then pumps the oil through the various pipes and valves of the hydraulic system to the hydraulic clutch and the cooling and lubrication system.

[0052] Figure 1 The figure shows the power transmission process in the engine direct drive mode, in which the engine acts as a power source, driving the oil supply pump to operate, pressurizing the oil, and then filling the clutch and cooling lubrication system through the valve. The clutch engages, the engine power is transmitted to the wheel end, and the P1 motor and P3 motor are shut down.

[0053] Figure 2 The figure shows the power transmission process in the extended-range mode, in which the engine runs, driving the oil pump and the P1 motor to run. The oil pump pressurizes the oil and pumps it to the cooling and lubrication system to help cool and lubricate the engine and various components. The clutch remains isolated, the P1 motor generates electricity, and the P3 motor consumes electricity to drive the vehicle.

[0054] Figure 3 The figure shows the power transmission process in pure electric mode, in which the engine is stopped and the P3 motor works to drive the vehicle. In this mode, the cooling of the P3 motor and the cooling and lubrication of various components require the pumping of oil by an additional electronic pump.

[0055] During the above process, the fuel supply pump can serve as the power source of the hydraulic system to pump the oil when the engine is started. However, the engine does not start under some working conditions and requires an additional electronic pump as a power source. The electronic pump will be idle when the fuel supply pump is running, and the components are not fully utilized, resulting in a waste of resources.

[0056] The present application provides a hybrid vehicle hydraulic system that can effectively utilize components in the hydraulic system and improve the problem of resource waste.

[0057] In one embodiment, the hybrid vehicle hydraulic system is Figure 4 As shown, it includes an oil supply main line 1, an oil supply pump 2, a hydraulic motor 3 and a control motor 4.

[0058] The oil supply main line 1 connects the oil storage unit and the cooling and lubrication system of the hybrid vehicle. The oil storage unit is such as an oil tank, an oil pan, etc. An oil suction filter is provided at the outlet of the oil storage unit. The oil suction filter is used to protect the oil supply pump 2 and other hydraulic components to avoid the inhalation of contaminated impurities and effectively control the pollution of the hydraulic system.

[0059] The cooling and lubrication system is based on oil cooling technology. Oil channels are formed on components that need cooling or lubrication (such as engines, motors, generators, and various controllers). The oil pumped into the cooling and lubrication system circulates to remove heat or act as a lubricant. Its specific structure will not be described here.

[0060] The oil supply pump 2 is arranged upstream of the oil supply main line 1, that is, at one end close to the oil storage unit, and is used to suck oil from the oil storage unit. The oil supply pump 2 can be a mechanical pump with a fixed displacement. In some methods, a variable displacement pump is used, and the displacement can be adjusted based on actual conditions, which will be explained later.

[0061] The power input end of the oil supply pump 2 is connected to the engine of the hybrid vehicle. When the engine is running, the oil supply pump 2 is started to pump oil from the oil storage unit to the cooling and lubrication system.

[0062] The hydraulic motor 3 is arranged downstream of the oil supply main line 1 , that is, the inlet of the hydraulic motor 3 is connected to the outlet of the oil supply pump 2 , and the outlet of the hydraulic motor 3 is connected to the cooling and lubricating system.

[0063] The hydraulic motor 3 is a type such as a gear motor or a vane motor. When high-pressure oil enters the hydraulic motor 3, it pushes the internal moving parts (such as gears or blades), generates torque, and drives the connecting shaft to rotate; or when low-pressure oil enters the hydraulic motor 3, the low-pressure oil is pressurized under the drive of the control motor 4.

[0064] The output shaft of the regulating motor 4 is connected to the connecting shaft of the hydraulic motor 3, thereby performing power transmission.

[0065] Among them, the regulating motor 4 is used to execute the corresponding control mode according to whether the engine is running. The corresponding control mode includes the power generation control mode and / or flow monitoring mode when the engine is running, and the oil pumping control mode when the engine is stopped.

[0066] In the power generation control mode, high-pressure oil enters the hydraulic motor 3, and under the push of the oil, the connecting shaft drives the output shaft of the control motor 4 to rotate. At this time, the control motor 4 is controlled as a generator, applying electromotive force and generating torque in the opposite direction to achieve power generation.

[0067] In the flow monitoring mode, the actual flow rate flowing through the hydraulic motor 3 is monitored. Specifically, the displacement of the hydraulic motor 3 per rotation is a fixed value. The actual flow rate can be calculated by monitoring and controlling the rotation speed of the motor 4. The calculated actual flow rate can be used for system control. Compared with obtaining the flow rate by sensor induction, the setting of sensors can be reduced in this mode.

[0068] In the oil pump control mode, the regulating motor 4 and the hydraulic motor 3 form an electronic pump. The regulating motor 4 actively outputs power to drive the hydraulic motor 3 to operate, pressurize the oil, and pump it to the cooling and lubrication system.

[0069] The operation process of the above embodiment is described below:

[0070] When the engine is started (e.g. in direct drive mode, such as Figure 5 As shown), the engine drives the oil pump 2 to operate, draws oil from the oil storage unit, and pumps it to the cooling and lubrication system. The characteristic of hybrid vehicles is that the speed of the oil pump 2 is coupled with the engine or vehicle speed, and the engine operates based on the driving needs of the vehicle. In this case, the higher the engine speed / the higher the vehicle speed, the higher the speed of the oil pump 2. The displacement of the oil pump 2 is fixed, and the higher the speed of the oil pump 2, the more oil is discharged, and the greater the power consumption. While meeting the cooling and lubrication needs, it also generates more power waste. At this time, the control motor 4 plays the role of generating electricity. The control motor 4 applies the electromotive force and generating torque in the opposite direction to recover energy. The control motor 4 is correspondingly connected to the battery to store the recovered electrical energy.

[0071] In the engine direct drive mode, the flow monitoring mode can also be implemented synchronously. By monitoring and controlling the speed of the motor 4, the actual flow through the hydraulic motor 3 can be obtained according to the speed of the motor 4 and the displacement of the hydraulic motor 3.

[0072] In another case, when the engine is started (e.g. in range-extending mode, e.g. Figure 6 As shown), the flow monitoring mode can be implemented separately. In the extended-range mode, the engine runs based on the power generation demand and the engine speed is relatively stable. In order to avoid introducing additional loads and increasing system losses, the motor 4 is regulated not to enter the power generation control mode and only flow monitoring is performed.

[0073] When the engine is stopped (e.g. in pure electric mode, such as Figure 7As shown), the oil supply pump 2 also enters a stopped state. At this time, the regulating motor 4 enters the oil pump control mode. The regulating motor 4 actively outputs power to drive the hydraulic motor 3 to rotate, suck oil from the oil storage unit, and pump it into the cooling and lubrication system.

[0074] In the above embodiment, by improving the system structure, the working characteristics of the oil supply pump 2 and the control motor 4 are effectively combined, so that the combination of the control motor 4 and the hydraulic motor 3 can play the role of energy recovery or flow monitoring when the engine is started, and play the role of pumping oil when the engine and the oil supply pump 2 are stopped, thereby reducing the idleness of components in the hydraulic system and reducing resource waste.

[0075] On the other hand, reducing resource waste is also reflected in energy recovery. Through system structure improvements, when the engine is started, especially in the engine direct drive mode, the oil is pressurized by the oil supply pump 2 and enters the hydraulic motor 3, driving the hydraulic motor 3 to rotate, and further driving the control motor 4 to generate electricity. In this process, part of the energy consumed by the engine is recovered to avoid energy waste.

[0076] In some embodiments, the selected oil supply pump 2 still has an unobstructed flow channel inside when it is stopped, such as a plunger pump, so that the hydraulic motor 3 can absorb oil from the oil storage unit.

[0077] In other embodiments, a bypass line 6 is provided. When the control motor 4 operates in the pumping control mode, the hydraulic motor 3 draws oil from the bypass line 6, reducing pipeline resistance. For example, the bypass line 6 connects the oil storage unit and the inlet of the hydraulic motor 3, and a motor suction reversing valve 7 is provided on the bypass line 6. A system pressure control valve 5 is provided on the main oil supply line 1 between the hydraulic motor 3 and the oil supply pump 2.

[0078] Motor oil suction reversing valve 7 closes when the engine is running and opens when the engine is stopped. System pressure control valve 5 opens when the engine is running and closes when the engine is stopped. Therefore, in engine direct drive mode or range-extended mode, when the engine drives oil pump 2 to pump oil, oil supply main line 1 remains unobstructed, and oil enters hydraulic motor 3 from oil supply main line 1. In pure electric mode, the engine and oil pump 2 are stopped, bypass line 6 remains unobstructed, and oil is sucked from bypass line 6 to hydraulic motor 3.

[0079] Possibly, the system pressure control valve 5 and the motor oil suction reversing valve 7 are electrically controlled valves, and execute corresponding switching instructions according to whether the engine is running.

[0080] One feasible way is that the system pressure control valve 5 and the motor oil suction reversing valve 7 realize switching based on the hydraulic pressure provided by the oil supply pump 2. For example, the system pressure control valve 5 and the motor oil suction reversing valve 7 are both provided with a hydraulic sensing chamber and a pressure balancing chamber, and a sliding valve core is provided between the hydraulic sensing chamber and the pressure balancing chamber. The hydraulic sensing chambers of the system pressure control valve 5 and the motor oil suction reversing valve 7 are both connected to the outlet of the oil supply pump 2, and a force balancing element is provided in the pressure balancing chamber; when the thrust of the hydraulic sensing chamber is greater than the thrust of the pressure balancing chamber, the sliding valve core slides through the system pressure control valve 5 and closes the motor oil suction reversing valve 7.

[0081] FIG4 shows a simplified schematic structure of a sliding valve core. When the arrow portion of the sliding valve core is connected to a pipeline, it indicates that the pipeline is connected.

[0082] The force-balancing element in the pressure-balancing chamber uses hydraulic pressure, pneumatic pressure, or a balancing spring to provide balancing thrust. For example, the motor oil intake reversing valve 7 has a hydraulic sensing chamber on the left side of the sliding spool and a pressure-balancing chamber on the right side, with a balancing spring installed in each of the pressure-balancing chambers. The system pressure control valve 5 has a hydraulic sensing chamber on the right side of the sliding spool and a pressure-balancing chamber on the left side, with a balancing spring installed in each of the pressure-balancing chambers.

[0083] The switching process of motor oil suction reversing valve 7: When oil supply pump 2 is operating, high-pressure oil enters the hydraulic sensing chamber. As the hydraulic pressure increases, the oil pushes the sliding valve core to the right, until the flow path inside motor oil suction reversing valve 7 is closed. When oil supply pump 2 stops, the sliding valve core moves to the left under the action of the balance spring, opening the internal flow path.

[0084] The opening and closing process of system pressure control valve 5: When oil supply pump 2 is operating, high-pressure oil enters the hydraulic sensing chamber. As the hydraulic pressure increases, the oil pushes the sliding valve core to the left, until the flow path inside system pressure control valve 5 is opened. When oil supply pump 2 stops, the sliding valve core moves to the left under the action of the balance spring, closing the internal flow path.

[0085] The oil supply pump 2 is also used to provide high-pressure oil to the hydraulic clutch 9 connecting the engine and the wheel end. Specifically, the hybrid vehicle hydraulic system also includes a clutch pressure switching valve 8. The outlet of the clutch pressure switching valve 8 is connected to the hydraulic clutch 9, and the inlet is connected to the outlet of the oil supply pump 2. The outlet of the clutch pressure switching valve 8 is also connected to the pressure balance chamber of the system pressure control valve 5.

[0086] The clutch pressure switch valve 8 adopts a solenoid valve, which is controlled to open in the engine direct drive mode. When the oil pump 2 is working, the oil is pumped into the hydraulic clutch 9, and the power output by the engine is transmitted to the wheel end.

[0087] Define the pressure at the outlet of oil pump 2 as the system pressure P s(or called pressure, that is, the pressure per unit area), system pressure P s Generate thrust F at the right end of system pressure control valve 5 s .

[0088] Define the target oil filling pressure P of the hydraulic clutch 9 c , which generates a balancing thrust F at the left end of the system pressure control valve 5 c And, generally, the target oil filling pressure P c Less than system pressure P s .

[0089] The balance spring is defined as pre-loaded to generate a balance thrust F. k .

[0090] It can be understood that the opening condition of the system pressure control valve 5 in the engine direct drive mode meets F s =F c +F k .

[0091] In the range-extending mode, the clutch pressure switch valve 8 is closed, and the thrust generated by the oil at the left end of the system pressure control valve 5 disappears. Therefore, the opening condition of the system pressure control valve 5 in the range-extending mode meets F s =F k .

[0092] Therefore, compared with the extended-range mode, the opening pressure of the system pressure control valve 5 is higher in the engine direct-drive mode, and the oil pump 2 outputs oil at a higher pressure and consumes more system energy, which is conducive to the stable engagement of the hydraulic clutch 9. However, excess high-pressure oil overflows from the system pressure control valve 5. If the energy carried by the overflowing high-pressure oil is not utilized, energy waste will be caused. In this application, when the oil passes through the hydraulic motor 3, the hydraulic motor 3 drives the control motor 4 to generate electricity, thereby realizing effective energy recovery.

[0093] In the range-extending mode, the lower oil pressure can open the system pressure control valve 5. In order to avoid wasting engine energy, the motor 4 is regulated not to generate electricity, and no reverse electromotive force and generating torque are applied to avoid hydraulic blockage and energy waste.

[0094] In some embodiments, the hybrid vehicle hydraulic system also includes a motor controller 11 and a vehicle controller 12. The motor controller 11 is connected to the control motor 4 and is used to implement specific control logic on the control motor 4. The vehicle controller 12 is connected to the motor controller 11. The vehicle controller 12 is used to determine whether the engine of the hybrid vehicle is running and send a signal indicating whether the engine is running to the motor controller 11. The motor controller 11 can control the control motor 4 to execute a corresponding control mode according to whether the engine is running.

[0095] In power generation control mode, motor controller 11 controls the inlet pressure at the inlet of hydraulic motor 3 based on the inlet pressure. By adjusting the reverse electromotive force and power generation torque, the inlet pressure is maintained within a reasonable range to avoid excessive resistance and increased system energy consumption. For this purpose, a pressure sensor 10 is provided at the inlet of hydraulic motor 3 to sense the hydraulic pressure.

[0096] In some embodiments, the oil supply pump 2 is a variable displacement pump that can adaptively adjust the displacement of the oil supply pump 2 based on the required flow rate of the cooling and lubrication system. For example, the oil supply pump 2 is connected to the vehicle controller 12 and adjusts its displacement in response to signals from the vehicle controller 12. The required flow rate of the cooling and lubrication system is used as the target flow rate. In flow monitoring mode, the actual flow rate is calculated based on the speed of the control motor 4 and the displacement of the hydraulic motor 3. When the actual flow rate is less than the target flow rate, the displacement of the oil supply pump 2 is increased, and the oil supply pump 2 provides more oil when the engine speed remains unchanged. When the actual flow rate is greater than the target flow rate, the displacement of the oil supply pump 2 is reduced, thereby reducing oil pumping while maintaining stable engine operation, thereby reducing system energy consumption.

[0097] In one embodiment, a control method for a hybrid vehicle hydraulic system is provided, which is applied to the hybrid vehicle hydraulic systems provided in the aforementioned embodiments.

[0098] like Figure 8 As shown, the control method exemplarily includes the following steps:

[0099] Step 110 , obtaining the engine status of the hybrid vehicle and determining whether the engine is running.

[0100] In a hybrid vehicle, engine-related operating signals, such as engine speed and engine start signal, can be collected based on the vehicle controller 12. When the engine speed is greater than zero, the engine is considered to be in a running state, otherwise it is in a stopped state.

[0101] Step 120 : Control the motor 4 to execute a corresponding control mode according to whether the engine is running.

[0102] As mentioned above, when the engine is running, the control motor 4 is controlled to operate in the power generation control mode and / or the flow monitoring mode. For example, in the engine direct drive mode, the power generation control mode and the flow monitoring mode are implemented to control the control motor 4 to generate electricity, and monitor the speed of the control motor 4 while generating electricity. The actual flow through the hydraulic motor 3 is obtained according to the speed of the control motor 4 and the displacement of the hydraulic motor 3.

[0103] For example, in the extended-range mode, the flow monitoring mode is implemented to provide flow parameters for system control.

[0104] When the engine is stopped, for example, in pure electric mode, the control motor 4 is controlled to execute the oil pump control mode. The control motor 4 consumes electrical energy to output power, drives the hydraulic motor 3 to pressurize the oil, draws oil from the oil storage unit and pumps it to the cooling and lubrication system.

[0105] It is understandable that in the oil pump control mode, the control motor 4 can also monitor the flow rate. At this time, the speed of the control motor 4 is adjusted based on the actual flow rate obtained by monitoring, so that the actual flow rate meets the required flow rate of the cooling and lubrication system.

[0106] By adopting the above control method, on the one hand, the hardware resources of the hydraulic system are effectively utilized so that the role of the hardware resources can be fully exerted; on the other hand, energy is effectively recovered to reduce energy waste.

[0107] As mentioned above, the hybrid vehicle hydraulic system also includes a system pressure control valve 5, a bypass line 6 and a motor oil suction reversing valve 7. The system pressure control valve 5 is arranged on the oil supply main line 1 between the hydraulic motor 3 and the oil supply pump 2; the bypass line 6 connects the oil storage unit and the inlet of the hydraulic motor 3; the motor oil suction reversing valve 7 is arranged on the bypass line 6.

[0108] In some embodiments, when the system pressure control valve 5 and the motor oil suction reversing valve 7 are electrically controlled valves, the control method further includes turning on the system pressure control valve 5 when the engine is running; and turning on the motor oil suction reversing valve 7 when the engine is stopped.

[0109] In some other possible implementations, the system pressure control valve 5 and the motor oil suction reversing valve 7 are opened or closed based on the hydraulic pressure provided by the oil supply pump 2 .

[0110] The following describes the control mode:

[0111] 1. In the power generation control mode, the inlet pressure of the hydraulic motor 3 is obtained; based on the deviation between the inlet pressure and the target pressure, the power generation torque of the motor 4 is controlled to keep the inlet pressure consistent with the target pressure, wherein the target pressure is determined based on the preset system pressure and preset pressure drop of the oil supply main line 1.

[0112] For example, define the inlet pressure as P m .

[0113] The preset system pressure is calibrated based on the condition that the hydraulic system can normally supply oil to the hydraulic clutch 9 and the cooling lubrication system. For example, in the engine direct drive mode, according to the system pressure control valve 5 opening condition F s =F c +F k , determine the preset system pressure is the system pressure P at the outlet of the oil pump 2 when the system pressure control valve 5 is opened s .

[0114] The preset pressure drop ΔP is determined by calibration. The calibration process takes into account the normal oil pressure drop when the engine is running, the effect of the resistance caused by the power generation torque on the oil pressure in the hydraulic system, etc.

[0115] When the engine is running, the oil supply pump 2 pumps the oil to the hydraulic motor 3. Due to the change of the engine speed, the oil pressure provided by the oil supply pump 2 is unstable. The inlet pressure of the hydraulic motor 3 is monitored. When the inlet pressure is too high, the power generation torque is reduced, the oil resistance is reduced, and it is easier to flow through the hydraulic motor 3, thereby reducing the inlet pressure, limiting the energy recovery power, and avoiding increasing the energy consumption of the system; when the inlet pressure is too low, the power generation torque is increased, the energy of the overflowing oil is reasonably and effectively recovered, and the inlet pressure is maintained stable. The stable inlet pressure of the hydraulic motor 3 is further conducive to the stability of the system pressure.

[0116] 2. In the flow monitoring mode, the speed of the control motor 4 is obtained; based on the speed of the control motor 4 and the displacement of the hydraulic motor 3, the actual flow through the hydraulic motor 3 is obtained.

[0117] The flow monitoring mode can be applied in the engine direct drive mode, range extension mode or pure electric mode of the hybrid vehicle.

[0118] The displacement of the hydraulic motor 3 is the amount of oil that passes through the rotor of the hydraulic motor 3 during one rotation. The rotational speed of the hydraulic motor 3 corresponds to the rotational speed of the control motor 4. For example, a one-to-one conversion can be performed. The actual flow rate flowing through the hydraulic motor 3 per unit time can be determined by multiplying the displacement of the hydraulic motor 3 by the rotational speed of the control motor 4.

[0119] 3. Oil pump control mode. This mode is used in the pure electric mode of hybrid vehicles. In this mode, the output power of motor 4 is regulated, and hydraulic motor 3 draws oil from the oil storage unit and pumps the oil to the cooling and lubrication system. In this mode, the speed of motor 4 can be determined based on the required flow of the cooling and lubrication system.

[0120] In some embodiments, the oil supply pump 2 is a variable displacement pump, and the control method may further include controlling the displacement of the oil supply pump 2. For example, when the engine is running, the actual flow rate flowing through the hydraulic motor 3 is obtained. As mentioned above, the actual flow rate is obtained based on the speed of the control motor 4 and the displacement of the hydraulic motor 3; based on the deviation between the actual flow rate and the target flow rate, the displacement of the oil supply pump 2 is controlled, wherein the target flow rate is determined based on the required flow rate of the cooling and lubrication system.

[0121] The following describes the control process of the hydraulic system according to the different power sources of the hybrid vehicle.

[0122] 1. Engine direct drive mode, such as Figure 5 shown.

[0123] 1.1. Energy recovery working conditions:

[0124] The engine and the wheel end are connected through the hydraulic clutch 9, which directly drives the vehicle forward. The engine starts, driving the oil pump 2 to work, sucking the oil with a flow rate of Q from the oil suction filter and discharging it into the oil supply main line 1. The clutch pressure switch valve 8 is energized and starts working, and the oil chamber of the hydraulic clutch 9 is filled with oil. The target oil filling pressure is P c At the same time, the oil in the hydraulic clutch 9 oil chamber enters the left end of the system pressure control valve 5, generating thrust F c The preload of the balance spring on the left end of the system pressure control valve 5 is F k , the system pressure acting on the right end of the system pressure control valve 5 is the system pressure P s The thrust generated is F s , so the system pressure P s Satisfy F s =F c +F k , so that the system pressure control valve 5 opens to overflow.

[0125] At this time, the system power loss W=P s *Q.

[0126] After the oil flow Q pumped out by the oil supply pump 2 meets the pressure maintenance requirement, most of it overflows through the system pressure control valve 5, goes to the hydraulic motor 3, and then goes to the cooling and lubrication system. At the same time, the system pressure acts on the left end of the motor oil suction reversing valve 7, causing it to overcome the balance spring and be in a closed state, preventing the oil overflowing from the system pressure control valve 5 from returning to the oil pool through the motor oil suction reversing valve 7 and affecting the cooling and lubrication.

[0127] 1.2. Hydraulic system energy recovery function:

[0128] The oil overflowing from the system pressure control valve 5 enters the hydraulic motor 3, driving the hydraulic motor 3 to rotate, thereby driving the control motor 4 to rotate. The motor controller 11 applies an electromotive force and generating torque in the opposite direction to the rotating control motor 4, realizing motor power generation and storing it in the battery.

[0129] 1.3. Hydraulic system energy recovery power:

[0130] During the rotation of the hydraulic motor 3, a certain negative torque will be generated due to the energy recovery of the motor, which will hinder the rotation of the hydraulic motor 3, causing the oil entering the hydraulic motor 3 to generate an inlet pressure P m The power of the hydraulic motor 3 driving the motor 4 is P m *Q, the efficiency of converting motor rotational energy into electrical energy is η (η<1, there must be loss in the energy conversion process), and the energy recovery power is P m *Q*η.

[0131] 1.4. Energy recovery power limit:

[0132] In order to avoid extra energy waste in the hydraulic system, it is necessary to ensure that the power consumption of the engine-driven oil pump 2 is not greater than the actual demand. Therefore, a pressure sensor 10 is provided to monitor the inlet pressure P of the hydraulic motor 3. m To ensure P m <P s When the power generation torque is too large during motor energy recovery, the motor controller 11 recognizes the signal and reduces the power generation torque.

[0133] 1.5. During direct drive, the flow rate is monitored and adaptively adjusted while energy recovery is being performed:

[0134] Since the displacement of the hydraulic motor 3 is fixed, the amount of oil passing through it during one rotation is fixed at q. Therefore, by regulating the speed n of the motor 4, the actual flow Ql entering the cooling and lubrication system can be known. When Ql is less than the target flow (the target flow is obtained by calibration testing), the motor controller 11 transmits a signal to the variable-displacement oil supply pump 2 to increase the displacement, so that more oil flow Q can be provided at the same engine speed to meet the cooling and lubrication requirements; when Ql is greater than the target flow, the motor controller 11 transmits a signal to the oil supply pump 2 to reduce the displacement, so that a smaller cooling and lubrication flow Q can be provided at the same engine speed to reduce system energy consumption.

[0135] Second, the extended range mode, such as Figure 6 shown.

[0136] In extended range mode, cooling and lubrication flow is adaptively adjusted:

[0137] During extended-range driving, the engine operates to drive motor P1 for power generation, while motor P3 drives the wheels. The engine is disconnected from the wheel ends, hydraulic clutch 9 is deactivated, and clutch pressure switch valve 8 is deenergized. The engine then drives fuel pump 2 to provide cooling and lubrication flow to the motor and gear bearings. The clutch pressure switch valve 8 deenergization signal and the engine start signal are transmitted via vehicle controller 12 to motor controller 11. Motor controller 11 recognizes this extended-range mode and, to avoid introducing additional load and increasing system losses, disables energy recovery in motor 4 and instead monitors flow. When Q1 falls below the target flow rate, motor controller 11 signals fuel pump 2 to increase the displacement of variable-displacement fuel pump 2, providing more cooling and lubrication flow at the same engine speed. When Q1 exceeds the target flow rate, motor controller 11 signals fuel pump 2 to reduce its displacement, providing less cooling and lubrication flow at the same engine speed, thereby reducing system energy consumption.

[0138] 3. Pure electric mode, such as Figure 7 As shown:

[0139] When the vehicle is operating in pure electric mode, the P3 motor drives the wheels, the engine is not started, the oil pump 2 is not operating, there is no oil pressure on the left side of the motor oil suction reversing valve 7, and the inlet of the hydraulic motor 3 is connected to the outlet of the oil suction filter. At this time, the engine inoperative signal and the P3 motor operating signal are transmitted to the motor controller 11 via the vehicle controller 12. At this time, the motor controller 11 recognizes that the vehicle has entered pure electric mode and activates the oil pumping function of the hydraulic motor 3. The drive control motor 4 drives the hydraulic motor 3 to rotate, sucking oil from the oil storage unit through the oil suction filter into the inlet of the hydraulic motor 3 and discharging it into the cooling and lubrication system to ensure the cooling and lubrication of the hybrid box, motor, and gear bearing system.

[0140] It should be understood that although Figure 8 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 8 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0141] For the specific definition of the control method, please refer to the definition of the hybrid vehicle hydraulic system above, which will not be repeated here.

[0142] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A hybrid vehicle hydraulic system, characterized in that: include: An oil supply main line (1), the oil supply main line (1) connecting the oil storage unit and the cooling and lubrication system of the hybrid vehicle; An oil supply pump (2) is arranged upstream of the oil supply main line (1), and a power input end of the oil supply pump (2) is connected to the engine of the hybrid vehicle. When the engine is running, the oil supply pump (2) is driven to start and pump oil from the oil storage unit to the cooling and lubrication system; A hydraulic motor (3) is arranged downstream of the oil supply main line (1); a regulating motor (4), wherein an output shaft of the regulating motor (4) is connected to a connecting shaft of the hydraulic motor (3); The regulating motor (4) is used to execute a corresponding control mode according to whether the engine is running, and the corresponding control mode includes a power generation control mode and / or a flow monitoring mode when the engine is running, and an oil pumping control mode when the engine is stopped.

2. The hybrid vehicle hydraulic system according to claim 1, characterized in that: Also includes: a system pressure control valve (5), the system pressure control valve (5) being arranged on the oil supply main line (1) between the hydraulic motor (3) and the oil supply pump (2); a bypass line (6), the bypass line (6) connecting the oil storage unit and the inlet of the hydraulic motor (3); A motor oil suction reversing valve (7) is provided on the bypass pipeline (6).

3. The hybrid vehicle hydraulic system according to claim 2, characterized in that: The system pressure control valve (5) and the motor oil suction reversing valve (7) are both provided with a hydraulic sensing chamber and a pressure balancing chamber, a sliding valve core is provided between the hydraulic sensing chamber and the pressure balancing chamber, the hydraulic sensing chambers of the system pressure control valve (5) and the motor oil suction reversing valve (7) are both connected to the outlet of the oil supply pump (2), and a force balancing element is provided in the pressure balancing chamber; when the thrust of the hydraulic sensing chamber is greater than the thrust of the pressure balancing chamber, the sliding valve core slides to conduct the system pressure control valve (5) and close the motor oil suction reversing valve (7).

4. The hybrid vehicle hydraulic system according to claim 3, characterized in that: Also includes: a clutch pressure switch valve (8), wherein the outlet of the clutch pressure switch valve (8) is connected to the hydraulic clutch (9), and the inlet is connected to the outlet of the oil supply pump (2); the hydraulic clutch (9) is a clutch between the engine and the wheel end; The outlet of the clutch pressure switching valve (8) is also connected to the pressure balance chamber of the system pressure control valve (5).

5. The hybrid vehicle hydraulic system according to claim 1, characterized in that: Also includes: a pressure sensor (10), the pressure sensor (10) being arranged at the inlet of the hydraulic motor (3); a motor controller (11), the motor controller (11) being connected to the regulating motor (4) and the pressure sensor (10), and being used to control the regulating motor (4) to execute a corresponding control mode according to whether the engine is running, and to control the generating torque of the regulating motor (4) based on the inlet pressure sensed by the pressure sensor (10) in a generating control mode; A vehicle controller (12) is connected to the motor controller (11) and is used to determine whether the engine of the hybrid vehicle is running.

6. The hybrid vehicle hydraulic system according to claim 1, characterized in that: The oil supply pump (2) is a variable displacement pump.

7. A method for controlling a hybrid vehicle hydraulic system, characterized in that: A hybrid vehicle hydraulic system according to any one of claims 1 to 6, comprising: Obtain the engine status of the hybrid vehicle and determine whether the engine is running; According to whether the engine is running, the control motor (4) is controlled to execute a corresponding control mode, including controlling the control motor (4) to operate in a power generation control mode and / or a flow monitoring mode when the engine is running, or controlling the control motor (4) to operate in an oil pumping control mode when the engine is stopped.

8. The control method of the hybrid vehicle hydraulic system according to claim 7, characterized in that: The controlling the regulating motor (4) to operate in a power generation control mode and / or a flow monitoring mode includes: In the power generation control mode, obtaining the inlet pressure of the hydraulic motor (3); According to the deviation between the inlet pressure and the target pressure, the generating torque of the regulating motor (4) is controlled so that the inlet pressure is kept consistent with the target pressure, wherein the target pressure is determined according to a preset system pressure and a preset pressure drop of the oil supply main line (1).

9. The control method of the hybrid vehicle hydraulic system according to claim 7, characterized in that: The controlling the regulating motor (4) to operate in a power generation control mode and / or a flow monitoring mode includes: In the flow monitoring mode, obtaining the rotational speed of the control motor (4); The actual flow rate flowing through the hydraulic motor (3) is obtained according to the rotation speed of the control motor (4) and the displacement of the hydraulic motor (3).

10. The control method of the hybrid vehicle hydraulic system according to claim 7, characterized in that: The fuel supply pump (2) is a variable displacement pump, and after determining whether the engine is running, it also includes: When the engine is running, obtaining an actual flow rate flowing through the hydraulic motor (3), wherein the actual flow rate is obtained according to the rotation speed of the control motor (4) and the displacement of the hydraulic motor (3); According to the deviation between the actual flow rate and the target flow rate, the displacement of the oil supply pump (2) is controlled to make the actual flow rate consistent with the target flow rate, wherein the target flow rate is determined according to the required flow rate of the cooling and lubricating system.

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