A simulation platform for a hydraulic system of a hybrid vehicle and its implementation method

Abstract

The present invention belongs to the technical field of hydraulic systems for hybrid vehicles. A simulation platform for a hydraulic system of a hybrid vehicle includes a hydraulic system, a hydraulic simulation model, and a controller; the hydraulic system includes an oil inlet device, an oil return device, an oil sump, and a test workpiece, the oil inlet device is connected to the oil sump through an oil inlet pipeline, and the oil sump is connected to the test workpiece; the oil sump is connected to the oil return device through an oil return pipeline; the hydraulic system and the hydraulic simulation model are respectively connected to the controller; the controller is used to send control instructions to the hydraulic system and the hydraulic simulation model. The present invention effectively couples the hydraulic simulation model and the physical model of the hydraulic system to construct a simulation platform for the hydraulic system of a hybrid vehicle, which can simulate the actual operating conditions of the system to the greatest extent, improve the efficiency of the hydraulic system, and realize the determination of the shifting and clutch driving control performance of the electric drive transmission of new energy vehicles.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic systems for hybrid electric vehicles, and particularly relates to a simulation platform for a hydraulic system of a hybrid electric vehicle and a method for realizing the same. Background Art

[0002] Under the requirements of the increasingly scarce supply of oil resources and the sustainable development of environmental protection, finding new energy to replace traditional fuels has become an international issue. New energy technologies mainly based on electricity are actively applied to automobile production. In order to make up for the deficiencies of pure electric vehicles such as insufficient power and short driving range, hybrid electric vehicles that integrate motors and internal combustion engines have emerged as the times require. In order to meet the needs of hybrid vehicle models, the research technology of the hydraulic system of hybrid electric vehicles has also become an urgent matter at present. The hydraulic system of a hybrid electric vehicle is used for the shift and clutch drive control of the electric drive transmission of the hybrid electric vehicle. The hydraulic system is a complete set of devices that uses oil as the working medium, utilizes the pressure energy of the oil, and operates the hydraulic actuator through accessories such as control valves. The main reasons for the performance of the hydraulic system to be affected are that the output flow and output pressure of the hydraulic pump cannot match the flow and pressure required by the load, or pressure losses occur in the hydraulic pump and valve components. And there is a lack of effective verification means for optimizing the performance of the hydraulic system of a hybrid electric vehicle. If research is carried out through pure mathematical simulation, the simulation parameter settings are fixed, and the output results of the simulation model are relatively fixed, which cannot objectively reflect the actual situation, and there is a large difference between the simulation results and the actual situation; if experimental research is carried out through a pure physical model, it takes a long time for research and development, and the flexibility and controllability of the system are poor, and the real-time adjustment of the physical system cannot be realized. The semi-physical simulation technology that organically combines the simulation model and the physical model can reflect the actual operation optimization status of the hydraulic system to the greatest extent, and at the same time retain part of the flexibility and controllability of the simulation verification. Summary of the Invention

[0003] The invention overcomes the above-mentioned technical problems, and provides a simulation platform for a hydraulic system of a hybrid electric vehicle and a method for realizing the same, effectively couples the hydraulic simulation model and the physical model of the hydraulic system, constructs a hydraulic system of a hybrid electric vehicle based on semi-physical simulation, simulates the actual operating conditions of the system to the greatest extent, makes the hydraulic pump match the load, ensures high flexibility and controllability of the system equipment, improves the efficiency of the hydraulic system, and realizes the determination of the shift and clutch drive control performance of the electric drive transmission of new energy vehicles.

[0004] In order to achieve the above object, the invention adopts the following technical solutions:

[0005] A simulation platform for a hydraulic system of a hybrid vehicle, comprising a hydraulic system, a hydraulic simulation model and a controller; the hydraulic system includes an oil inlet device, an oil return device, an oil sump and a test workpiece, the oil inlet device is connected to the oil sump through an oil inlet pipeline, and the oil sump is connected to the test workpiece; the oil sump is connected to the oil return device through an oil return pipeline; the hydraulic simulation model is used to simulate the real hydraulic system of a hybrid vehicle; the hydraulic system and the hydraulic simulation model are respectively connected to the controller; the controller is used to send control instructions to the hydraulic system and the hydraulic simulation model.

[0006] As a further improvement of the present invention, the oil inlet device includes a clean oil tank, an oil pump motor, an oil inlet pump, a throttle valve, a check valve and a first filter, the clean oil tank is connected to the input end of the oil inlet pump; the oil pump motor is connected to the oil inlet pump to drive the oil inlet pump to work, the output end of the oil inlet pump is connected to the throttle valve; a check valve is provided at the input end of the oil sump; a first filter is provided in the oil inlet pipeline; the first filter is located between the throttle valve and the check valve;

[0007] The oil return device includes an oil return tank, an oil return pump, a relief valve and a second filter; the output end of the oil sump is connected to the input end of the oil return pump, the output end of the oil return pump is connected to the input end of the oil return tank; the relief valve is provided in the oil return pipeline; the second filter is provided in the oil return pipeline.

[0008] As a further improvement of the present invention, liquid level sensors are provided in both the clean oil tank and the oil return tank.

[0009] As a further improvement of the present invention, a cleanliness sensor is provided in the clean oil tank.

[0010] As a further improvement of the present invention, a temperature sensor, a heater and a cooler are also provided in the clean oil tank.

[0011] As a further improvement of the present invention, pressure gauges are respectively provided on the oil inlet pipeline and the oil return pipeline.

[0012] The present invention also provides a method for implementing a simulation platform for a hydraulic system of a hybrid vehicle, the method comprising the following steps:

[0013] Step 1: Build a physical model of the hydraulic system in AMESim software according to the principle structure of the hydraulic system;

[0014] Step 2: After performing graphical modeling based on the physical model of the hydraulic system, use Matlab / Simulink simulation software to establish a hydraulic simulation model, build each hydraulic component according to the physical model of the system, and then connect the models of each component according to the power flow of the system;

[0015] Step 3: Set parameters for the simulation models of each component in the hydraulic simulation model on the Simulink platform and perform simulations.

[0016] Step 4: Couple the physical model of the hydraulic system and the hydraulic simulation model for co-simulation, control the hydraulic system and the hydraulic simulation model using a controller, and construct a mechatronic hybrid vehicle hydraulic system simulation platform.

[0017] As a further improvement of the present invention, the hydraulic simulation model in Step 2 includes: the mathematical model of a hydraulic pump, the mathematical model of a check valve, the mathematical model of a throttle valve, and the mathematical model of a relief valve.

[0018] The hydraulic pump serves as the power source of the hydraulic system, and its specific mathematical model is:

[0019]

[0020] where q1 is the actual flow rate of the hydraulic pump; q0 is the theoretical flow rate of the hydraulic pump; G0 is the liquid conductance of the hydraulic pump; the inlet oil pressure is P0; the pressure at the oil outlet is P1; V1 is the outlet volume of the hydraulic pump; K is the bulk modulus of elasticity of the oil.

[0021] The check valve serves as a liquid resistance element in the hydraulic system, and its mathematical model is:

[0022]

[0023] where q1 is the flow rate through the check valve; R1 is the liquid resistance of the check valve, R1 = 128μl / πd 4 = 3.125×10 7 m 3 .Pa.S; P2 is the inlet pressure of the check valve; P3 is the outlet pressure of the check valve.

[0024] The throttle valve can stabilize the oil circuit of the hydraulic system, and its specific mathematical model is as follows:

[0025]

[0026] where q3 is the flow rate through the throttle valve; R2 is the liquid resistance of the throttle valve; G1 is the liquid conductance of the throttle valve, G1 = 3.09×10 -7 m 3 .Pa -1 .S -1 ; P5 is the inlet pressure of the throttle valve, p4 is the outlet pressure of the throttle valve.

[0027] The relief valve can maintain the oil circuit pressure of the hydraulic system at a constant value, and its specific mathematical model is as follows:

[0028] q4 = C(p6 - p7);

[0029] Wherein, q4 is the flow rate through the overflow valve; C is the comprehensive flow coefficient of the overflow valve, C = 0.964Re -0.05 , Re is the Reynolds number of the liquid. Here, the pipe Reynolds number is taken as 1500, so C = 0.669; p6 is the inlet pressure of the overflow valve; p7 is the outlet pressure of the overflow valve.

[0030] As a further improvement of the present invention, the hydraulic pump includes an inlet oil pump and a return oil pump.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The simulation platform of the hydraulic system of the hybrid vehicle of the present invention establishes the hydraulic system, hydraulic simulation model and controller of the simulation platform according to the equipment parameters. By improving the hydraulic system, it is beneficial to make the hydraulic pump match the load and improve the efficiency of the hydraulic system. The controller sends control instructions to the hydraulic system. After receiving the control instructions sent by the controller, the hydraulic system drives the components in the hydraulic simulation model to work, so as to realize the simulation of the dynamic characteristics of the hydraulic pressure. The joint simulation of the hydraulic system, hydraulic simulation model and controller effectively shortens the system modeling time of the equipment and improves the accuracy of the simulation model.

[0033] The implementation method of the simulation platform of the hydraulic system of the hybrid vehicle of the present invention, on the basis of traditional pure mathematical simulation, comprehensively considers the test focus, safety, flexibility and experimental conditions of the system, combines the hydraulic simulation model with the physical model of the hydraulic system to achieve an optimized performance test closer to the actual operating conditions of the system, while retaining the flexible controllability of the simulation verification. By modeling the mathematical models of the hydraulic pump, check valve, throttle valve and overflow valve, the main factors affecting the performance in the hydraulic system are explored, so as to master the energy consumption of the hydraulic system and improve the system efficiency. Description of the Drawings

[0034] Figure 1 is the structural block diagram of a simulation platform of a hydraulic system of a hybrid vehicle of the present invention;

[0035] Figure 2 is the simplified block diagram A of the hydraulic system of the present invention;

[0036] Figure 3 is the simplified block diagram B of the hydraulic system of the present invention;

[0037] Figure 4 is the hydraulic schematic diagram of the hydraulic system of the present invention;

[0038] Figure 5It is the Simulink simulation diagram of the hydraulic simulation model of the present invention;

[0039] Figure 6 It is the flow simulation diagram of the present invention's embodiment flowing through the inlet oil pump group;

[0040] Figure 7 It is the flow simulation diagram of the present invention's embodiment flowing through the valve body;

[0041] Figure 8 It is the flow simulation diagram of the present invention's embodiment flowing through the return oil pump group.

[0042] Among them, the labels in the attached drawings are: 1, hydraulic system; 2, hydraulic simulation model; 3, controller; 4, inlet oil device; 5, return oil device; 6, oil sump; 7, test workpiece; 8, cleaning fuel tank; 9, oil pump motor; 10, inlet oil pump; 11, throttle valve; 12, check valve; 13, first filter; 14, return oil fuel tank; 15, return oil pump; 16, overflow valve; 17, second filter; 18, liquid level sensor; 19, cleanliness sensor; 20, heater; 21, cooler; 22, temperature sensor; 23, pressure gauge; 24, liquid level switch; 25, third filter; Specific embodiments

[0043] The present invention will be further described below in conjunction with the attached drawings and embodiments. It should be noted that the specific embodiments of the present invention are only for more clearly describing the technical solution and cannot be used as a limitation on the protection scope of the present invention.

[0044] Please refer to Figures 1-7 , a simulation platform for a hydraulic system of a hybrid vehicle, including a hydraulic system 1, a hydraulic simulation model 2, and a controller 3; the hydraulic system 1 includes an inlet oil device 4, a return oil device 5, an oil sump 6, and a test workpiece 7. The inlet oil device 4 is connected to the oil sump 6 through an inlet oil pipeline, and the oil sump 6 is connected to the test workpiece 7; the oil sump 6 is connected to the return oil device 5 through a return oil pipeline; the hydraulic simulation model 2 is used to simulate a real hydraulic system of a hybrid vehicle; the hydraulic system 1 and the hydraulic simulation model 2 are respectively connected to the controller; the controller is used to send control instructions to the hydraulic system 1 and the hydraulic simulation model 2.

[0045] As a further improvement of the present invention, the oil inlet device 4 includes a cleaning fuel tank 8, an oil pump motor 9, an oil inlet pump 10, a throttle valve 11, a check valve 12, and a first filter 13. The cleaning fuel tank 8 is connected to the input end of the oil inlet pump 10; the oil pump motor 9 is connected to the oil inlet pump 10 to drive the oil inlet pump 10 to work, and the output end of the oil inlet pump 10 is connected to the throttle valve 11; a check valve 12 is provided at the input end of the oil sump 6; a first filter 13 is provided in the oil inlet pipeline; the first filter 13 is located between the throttle valve 11 and the check valve 12;

[0046] The oil return device 5 includes an oil return fuel tank 14, an oil return pump 15, a relief valve 16, and a second filter 17; the fuel tank of the hydraulic system 1 includes a cleaning fuel tank 8 and an oil return fuel tank 14, which are separated by a partition. The output end of the oil sump 6 is connected to the input end of the oil return pump 15, and the output end of the oil return pump 15 is connected to the input end of the oil return fuel tank 14; a relief valve 16 is provided in the oil return pipeline, and the excess oil in the system flows back into the oil return fuel tank 14 through the relief valve 16 to control the actual liquid level of the oil return pipeline; a second filter 17 is provided in the oil return pipeline. For the first filter 13 in the oil inlet pipeline, a filter with a filtration accuracy of 3μm is selected, and the second filter 17 in the oil return pipeline adopts two-stage filtration, with a maximum filtration accuracy of 10μm; a third filter 25 is also provided in the cleaning fuel tank 8 and the oil return fuel tank 14, and the third filter 25 is an air filter; the types of the oil inlet pump 10 and the oil return pump 15 both adopt vane pumps. Vane pumps have uniform oil delivery volume, small pressure pulsation, and high volumetric efficiency, but they have a relatively complex structure and are more sensitive to oil pollution. The upper computer communicates with the controller 3 through a CAN communication card and controls the oil pump motor 9 and each valve body according to the detection process. The parameters of the valve body and pipeline are calculated theoretically, including the model selection of various components. Then, according to the schematic diagram of the hydraulic system 1, a dynamic simulation model of the hydraulic system 1 is established in the simulation software environment, and the hydraulic system 1, the hydraulic simulation model 2, and the controller 3 are jointly simulated to verify the correctness of the theoretical calculation through simulation and perform dynamic analysis on each system. Thus, the shift and clutch drive control performance of the electric drive transmission of new energy vehicles can be determined.

[0047] As a further improvement of the present invention, a liquid level sensor 18 and a liquid level switch 24 are provided in both the cleaning fuel tank 8 and the oil return fuel tank 14; a cleanliness sensor 19, a heater 20, and a cooler 21 are provided in the cleaning fuel tank 8. The cleanliness sensor 19 is used to test the cleanliness of the oil product and monitor the pollution degree of the hydraulic oil in real time.

[0048] As a further improvement of the present invention, a temperature sensor 22 is provided in the oil sump 6. A pressure gauge 23 and a relief valve 16 are respectively provided on the oil inlet pipeline and the oil return pipeline to detect the pressure of the hydraulic oil in the oil circuit and dredge it in time.

[0049] The simulation platform of the hydraulic system of the hybrid electric vehicle of the present invention establishes the hydraulic system 1, the hydraulic simulation model 2 and the controller 3 of the simulation platform according to the equipment parameters. By improving the hydraulic system 1, it is beneficial to make the hydraulic pump match the load and improve the efficiency of the hydraulic system 1. The controller sends control instructions to the hydraulic system 1. After receiving the control instructions sent by the controller, the hydraulic system 1 drives the components in the hydraulic simulation model 2 to work, so as to realize the simulation of the dynamic characteristics of the hydraulic pressure. The combined simulation of the hydraulic system 1, the hydraulic simulation model 2 and the controller 3 effectively shortens the system modeling time of the equipment and improves the accuracy of the simulation model.

[0050] The present invention also provides a method for realizing a simulation platform of a hydraulic system of a hybrid electric vehicle, and the method includes the following steps:

[0051] Step 1: Build a physical model of the hydraulic system 1 in the AMESim software according to the principle structure of the hydraulic system 1;

[0052] Step 2: After graphical modeling based on the physical model of the hydraulic system 1, use the Matlab / Simulink simulation software to establish a hydraulic simulation model 2, and the hydraulic simulation model 2 is used to simulate the real hydraulic system of the hybrid electric vehicle; build each hydraulic component according to the physical model of the system, and then connect the models of each component according to the power flow of the system;

[0053] Step 3: Set parameters for the simulation models of each component in the hydraulic simulation model 2 in the Simulink platform and perform simulation;

[0054] Step 4: Couple the physical model of the hydraulic system 1 and the hydraulic simulation model 2 for combined simulation, control the hydraulic system 1 and the hydraulic simulation model 2 with a controller, and build an electromechanical integrated simulation platform for the hydraulic system of the hybrid electric vehicle.

[0055] As a further improvement of the present invention, the hydraulic simulation model 2 in Step 2 includes: the mathematical model of the hydraulic pump, the mathematical model of the check valve 1212, the mathematical model of the throttle valve 1111, and the mathematical model of the relief valve 1616; wherein, the hydraulic pump includes an oil inlet pump 10 and an oil return pump 15.

[0056] The hydraulic pump is the power source of the hydraulic system, and the specific mathematical model is:

[0057]

[0058] Among them, q1 is the actual flow rate of the hydraulic pump; q0 is the theoretical flow rate of the hydraulic pump; G0 is the hydraulic conductance of the hydraulic pump; the inlet oil pressure is P0; the pressure at the oil outlet is P1; V1 is the outlet volume of the hydraulic pump; K is the bulk modulus of elasticity of the oil.

[0059] The one-way valve 12, as a liquid resistance element in the hydraulic system, has the following mathematical model:

[0060]

[0061] Among them, q1 is the flow rate through the one-way valve 12; R1 is the liquid resistance of the one-way valve 12, and R1 = 128μl / πd 4 = 3.125×10 7 m 3 .Pa.S; P2 is the inlet pressure of the one-way valve 12; P3 is the outlet pressure of the one-way valve 12; then the flow equation of the one-way valve 12 is:

[0062]

[0063] The throttle valve 11 can stabilize the oil circuit of the hydraulic system, and its specific mathematical model is as follows:

[0064]

[0065] Among them, q3 is the flow rate through the throttle valve 11; R2 is the liquid resistance of the throttle valve 11; G1 is the hydraulic conductance of the throttle valve 11, and G1 = 3.09×10 -7 m 3 .Pa -1 .S -1 ; P5 is the inlet pressure of the throttle valve 11, and p4 is the outlet pressure of the throttle valve 11; then the mathematical model of the throttle valve 11 can be written as:

[0066] q2 = 3.09×10 -7 (p5 - p4);

[0067] The overflow valve 16 can maintain the oil circuit pressure of the hydraulic system constant. In the large hydraulic system, if the influence of fluid force, Coulomb friction, viscous damping, and spool gravity is ignored, the flow equation of the overflow valve 16 can be simplified to obtain its specific mathematical model as follows:

[0068] q4 = C(p6 - p7);

[0069] Among them, q4 is the flow rate through the overflow valve 16; C is the comprehensive flow coefficient of the overflow valve 16, and C = 0.964Re -0.05, where Re is the Reynolds number of the liquid. Here, the pipe Reynolds number is taken as 1500, so C = 0.669; p6 is the inlet pressure of the overflow valve 16; p7 is the outlet pressure of the overflow valve 16. Then the mathematical model of the overflow valve 16 can be written as:

[0070] q4 = 0.669(p6 - p7);

[0071] Combined with the simplified diagram of the hydraulic system and the obtained mathematical models of the hydraulic pump and each valve, simulation is carried out in the Simulink environment.

[0072] The simulation platform of the present invention mainly conducts dynamic simulation on the pump group and various valve bodies in the hydraulic system 1. By calculating various mathematical models, preparations before simulation are made. In this embodiment, the rated speed of the hydraulic pump involved is 1500 rpm, and the displacement is 9.8 ml / r. The whole simulation process includes input, intermediate transmission, and output response. Taking the displacement of the hydraulic pump in the hydraulic system 1 as the input signal and the output pressure as the output signal, the changes of the pressure of the pump and various valve bodies in the system with the working time of the system are obtained through simulation respectively. Among them, various valve bodies include the check valve 12, the throttle valve 11 or the overflow valve 16.

[0073] See Figure 3 and Figure 6 , the oil pump motor 9 pumps the test oil out of the clean oil tank 8. As the speed of the oil pump motor 9 tends to be stable, the oil flow rate flowing through the inlet oil pump 10 will also tend to be stable. Overall, the change trend of the amount of test oil flowing through the inlet oil pump 10 with time shows a linear relationship. During the simulation process, the displacement of the inlet oil pump 10 is used as the input signal, and the simulation display graph is as Figure 6 , and the displayed result is the change trend of the pressure with time, which is basically in line.

[0074] See Figure 7 , after the test oil is pumped out by the hydraulic pump, it enters the oil pool 6 through the throttle valve 11 and the check valve 12, and then flows out from the oil outlet. Due to certain pressure limitations in the system. Therefore, both the throttle valve 11 and the check valve 12 are to ensure the stability of the oil pressure in the system pipeline. It can be seen from the models of the throttle valve 11 and the check valve 12 that the oil pressure and the flow rate show a linear relationship. The oil pressure in the pipeline after passing through the throttle valve 11 and the check valve 12 is also linear with time, and it can be seen from the simulation results that it is generally in line with the actual situation.

[0075] See Figure 8 , the pump group in the whole hydraulic system 1 uses the same model. So when the speed of the return oil pump 15 group reaches the rated speed, theoretically the flowing oil gradually tends to be stable and shows a linear relationship with time. The oil pressure after passing through the return oil pump 15 group should also be linear with time, which is basically in line with the simulation diagram.

[0076] The present invention combines the hydraulic simulation model 2 with the physical model of the hydraulic system 1 to achieve an optimized performance test closer to the actual operating conditions of the system, while retaining the flexible controllability of simulation verification. By modeling the mathematical models of the hydraulic pump, check valve 12, throttle valve 11, and relief valve 16, the main factors affecting the performance in the hydraulic system 1 are explored to master the energy consumption of the hydraulic system 1 and improve the system efficiency.

[0077] The above description is a detailed description of the preferred feasible embodiment of the present invention, but the embodiment is not intended to limit the patent application scope of the present invention. Any equivalent changes or modifications made under the technical spirit disclosed by the present invention shall fall within the patent scope covered by the present invention.

Claims

1. A simulation platform for a hydraulic system of a hybrid vehicle, characterized in that, It includes a hydraulic system (1), a hydraulic simulation model (2), and a controller (3); the hydraulic system (1) includes an oil inlet device (4), an oil return device (5), an oil sump (6), and a test workpiece (7). The oil inlet device (4) is connected to the oil sump (6) through an oil inlet pipeline, and the oil sump (6) is connected to the test workpiece (7); the oil sump (6) is connected to the oil return device (5) through an oil return pipeline; the hydraulic simulation model (2) is used to simulate the hydraulic system of a real hybrid vehicle; the hydraulic system (1) and the hydraulic simulation model (2) are respectively connected to the controller; the controller is used to send control instructions to the hydraulic system (1) and the hydraulic simulation model (2). The oil inlet device (4) includes a clean oil tank (8), an oil pump motor (9), an oil inlet pump (10), a throttle valve (11), a check valve (12), and a first filter (13). The clean oil tank (8) is connected to the input end of the oil inlet pump (10); the oil pump motor (9) is connected to the oil inlet pump (10) to drive the oil inlet pump (10) to work, and the output end of the oil inlet pump (10) is connected to the throttle valve (11); a check valve (12) is provided at the input end of the oil sump (6); a first filter (13) is provided in the oil inlet pipeline; the first filter (13) is located between the throttle valve (11) and the check valve (12). The oil return device (5) includes an oil return tank (14), an oil return pump (15), a relief valve (16), and a second filter (17); the output end of the oil sump (6) is connected to the input end of the oil return pump (15), and the output end of the oil return pump (15) is connected to the input end of the oil return tank (14); a relief valve (16) is provided in the oil return pipeline; a second filter (17) is provided in the oil return pipeline. The implementation method of the simulation platform includes the following steps: Step 1: Build a physical model of the hydraulic system (1) in AMESim software according to the principle structure of the hydraulic system (1). Step 2: After performing graphical modeling based on the physical model of the hydraulic system 1, use Matlab / Simulink simulation software to establish a hydraulic simulation model (2). Build each hydraulic component according to the physical model of the system, and then connect the models of each component according to the power flow of the system. Step 3: Set parameters for the simulation models of each component in the hydraulic simulation model (2) in the Simulink platform and perform simulation. Step 4: Couple the physical model of the hydraulic system (1) and the hydraulic simulation model (2) for co-simulation, use the controller (3) to control the hydraulic system (1) and the hydraulic simulation model (2), and construct an electromechanical integrated hydraulic system simulation platform for hybrid vehicles. The hydraulic simulation model (2) in the second step includes: the mathematical model of the hydraulic pump, the mathematical model of the check valve (12), the mathematical model of the throttle valve (11), and the mathematical model of the relief valve (16). The hydraulic pump is the power source of the hydraulic system (1), and the specific mathematical model is: Among them, q1 is the actual flow rate of the hydraulic pump ; q0 is the theoretical flow rate of the hydraulic pump; G0 is the hydraulic conductance of the hydraulic pump; the inlet oil pressure is P0; the pressure at the oil outlet is P1; V1 is the outlet volume of the hydraulic pump; K is the bulk modulus of elasticity of the oil; The check valve (12), as a fluid resistance element in the hydraulic system (1), has the following mathematical model: Among them, q1 is the flow rate through the one-way valve (12); R1 is the liquid resistance of the one-way valve (12), and R1 = 128 μl / πd 4 = 3.125×10 7 m 3 .Pa.S; P2 is the inlet pressure of the one-way valve (12); P3 is the outlet pressure of the one-way valve (12); The throttle valve (11) can stabilize the oil circuit of the hydraulic system (1), and its specific mathematical model is as follows: Among them, q3 is the flow rate through the throttle valve (11); R2 is the liquid resistance of the throttle valve (11); G1 is the liquid conductance of the throttle valve (11), and G1 = 3.09×10 -7 m 3 .Pa -1 .S -1 ; P5 is the inlet pressure of the throttle valve (11), and p4 is the outlet pressure of the throttle valve (11); The relief valve (16) can maintain the oil circuit pressure of the hydraulic system (1) at a constant value, and its specific mathematical model is as follows: q4 = C(p6 - p7); Among them, q4 is the flow rate through the overflow valve (16); C is the comprehensive flow coefficient of the overflow valve (16), C = 0.964Re -0.05 , Re is the Reynolds number of the liquid. Here, the pipe Reynolds number is taken as 1500, so C = 0.669; p6 is the inlet pressure of the overflow valve (16); p7 is the outlet pressure of the overflow valve (16).

2. The simulation platform of a hydraulic system for a hybrid vehicle according to claim 1, characterized in that: Level sensors (18) are provided in both the cleaning oil tank (8) and the return oil tank (14).

3. The simulation platform of a hydraulic system for a hybrid vehicle according to claim 1, characterized in that: A cleanliness sensor (19) is provided in the cleaning oil tank (8).

4. The simulation platform of a hydraulic system for a hybrid vehicle according to claim 1, characterized in that: A temperature sensor (22), a heater (20) and a cooler (21) are also provided in the cleaning oil tank (8).

5. The simulation platform of a hydraulic system for a hybrid vehicle according to claim 1, characterized in that: Pressure gauges (23) are respectively provided on the oil inlet pipeline and the oil return pipeline.

6. The simulation platform of a hydraulic system for a hybrid vehicle according to claim 1, characterized in that, The hydraulic pump includes an oil inlet pump (10) and an oil return pump (15).

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