Closed air supply unit rack for simulating vehicle air suspension and simulation method thereof

Abstract

The invention discloses a closed air supply unit rack for simulating a vehicle air suspension, which comprises an air storage tank A, an air storage tank B and an air storage tank C. The air storage tank A is used for simulating an air spring; the gas storage tank B is used for simulating the volume of a vehicle gas storage tank An air spring interface of the closed air supply unit is connected with the output end of the air storage tank A; the output port of the closed gas supply unit is connected with one input end of a gas storage tank B; the input port of the gas storage tank A is connected with the output end of a high-pressure gas source through an electromagnetic valve A; and the other output port of the gas storage tank A is connected with one input port of the gas storage tank C through the electromagnetic valve B. After the design of the air suspension system is completed, the working condition of the whole vehicle can be simulated, parameters of an air spring and parameters of an air storage tank in the air suspension system are matched, closed air supply unit software is debugged, the lifting rate of the air suspension is evaluated, and the development period and development cost of the air suspension system are reduced.

Description

Technical Field

[0001] The invention relates to a simulation device, in particular to a closed air supply unit stand for simulating vehicle air suspension and a simulation method thereof. Background Art

[0002] At present, the ground bench of the air suspension closed air supply unit is quite different from the actual application of the vehicle. When conducting the bench durability test, it is far away from the actual application of the vehicle, and it is impossible to evaluate the durability of the air supply unit in actual application. In addition, when carrying out the evaluation of different air suspension lifting rates, the definition of the vehicle air tank volume, and the software debugging of the closed air supply unit, all work must be carried out after the vehicle trial production is completed, which affects the development progress of the air supply system and the development cost is high. Summary of the invention

[0003] The object of the present invention is to provide a closed air supply unit stand for simulating vehicle air suspension and a simulation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A closed air supply unit bench for simulating vehicle air suspension, comprising an air tank A, an air tank B and an air tank C, wherein the air tank A is used to simulate an air spring; the air tank B is used to simulate the volume of a vehicle air tank;

[0006] The output end of the air storage tank A is used to connect with the air spring interface of the closed air supply unit;

[0007] An input end of the gas storage tank B is used to connect to an output port of the closed gas supply unit;

[0008] The input port of the gas storage tank A is connected to the output end of the high-pressure gas source through the solenoid valve A; the other output port of the gas storage tank A is connected to an input port of the gas storage tank C through the solenoid valve B; the gas storage tank A is also equipped with a pressure sensor A;

[0009] The output port of the gas storage tank B is connected to the input end of the gas storage tank C through the solenoid valve D; the other input port of the gas storage tank B is connected to the output end of the high-pressure gas source through the solenoid valve C; the gas storage tank B is also equipped with a pressure sensor B;

[0010] The gas storage tank C is also provided with another input port for replenishing gas, or an input port for replenishing gas is provided between the gas storage tank C and the compressor; the output port of the gas storage tank C is connected to the input end of the high-pressure gas source through the compressor; the gas storage tank C is also equipped with a pressure sensor C.

[0011] As a further solution of the present invention: a temperature sensor A is connected between the closed air supply unit and the air storage tank A, and a temperature sensor B and a flow sensor are connected between the closed air supply unit and the air storage tank B.

[0012] As a further solution of the present invention: a pressure protection valve B is installed between the gas storage tank B and the solenoid valve C, and a pressure protection valve A is installed between the solenoid valve A and the gas storage tank A.

[0013] As a further solution of the present invention: the solenoid valve A, solenoid valve B, pressure sensor A, temperature sensor A, closed air supply unit, temperature sensor B, flow sensor, pressure sensor B, solenoid valve C, solenoid valve D, compressor and pressure sensor C are all electrically connected to the controller ECU.

[0014] The simulation method of the closed air supply unit bench simulating the vehicle air suspension includes simulating the exhaust in the air spring, simulating the inflation in the air spring, simulating the closed air supply unit to replenish the air tank from the outside, simulating the closed air supply unit to replenish the air spring from the outside and simulating the closed air supply unit to self-check the pressure in the air spring and the air tank, as follows:

[0015] Simulate exhaust in the air spring: the controller ECU controls the compressed air pressure in the air tank B through the solenoid valve C and the solenoid valve D, and controls the compressed air pressure in the air tank A according to the load and height of the air spring; the closed air supply unit inhales the compressed air in the air tank A, which is discharged after being processed by the closed air supply unit and flows into the air tank B through the flow sensor; the controller ECU detects the amount of compressed air in the air tank A flowing through the closed air supply unit through the flow sensor, converts it to the height of the air spring, and further controls the pressure in the air tank A through the solenoid valve A and the solenoid valve B; until the air spring reaches the target load and height;

[0016] Simulate the inflation in the air spring: the controller ECU controls the compressed air pressure in the air tank B through the solenoid valve C and the solenoid valve D, and controls the compressed air pressure in the air tank A according to the load and height of the air spring; the closed air supply unit inhales the compressed air in the air tank B that flows through the flow sensor, and discharges it into the air tank A after being processed by the closed air supply unit; the controller ECU detects / converts the amount of compressed air in the air tank A that flows through the closed air supply unit through the flow sensor / pressure sensor B, converts it to the height of the air spring, and further controls the pressure in the air tank A through the solenoid valve A and the solenoid valve B; until the air spring reaches the target load and height;

[0017] The closed air supply unit is simulated to replenish air to the air tank from the outside: the controller ECU controls the volume and pressure in the air tank B through the solenoid valve D and the solenoid valve C according to the set volume and initial pressure of the air tank B; the closed air supply unit is running, and the outside air is sucked into the closed air supply unit through the filter A, and is discharged after being processed by the closed air supply unit and enters the air tank B through the flow sensor; the controller ECU detects the pressure change in the air tank B through the pressure sensor B until the replenishment pressure is reached;

[0018] The closed air supply unit is simulated to supply air to the air spring from the outside: the controller ECU controls the pressure in the air tank B through the solenoid valve D and the solenoid valve C according to the set initial state of the air spring; when the closed air supply unit is running, the outside air is sucked into the closed air supply unit through the filter AF, and is discharged after being processed by the closed air supply unit and enters the air tank B through the flow sensor; the controller ECU detects the amount of air flowing through the air tank B through the flow sensor, converts it to the height of the air spring, and further controls the pressure in the air tank B through the solenoid valve D and the solenoid valve C; until the air spring reaches the target load and height;

[0019] Simulate the closed air supply unit to self-check the pressure in the air spring and air tank: the closed air supply unit detects the pressure of air tank A and air tank B to achieve self-check; choose to compare and verify the pressure detected by the closed air supply unit with the test results of pressure sensor A and pressure sensor B.

[0020] As a further solution of the present invention: when simulating the exhaust of multiple air springs, after one air spring or air spring group completes the exhaust simulation, the controller ECU controls the solenoid valve A and the solenoid valve B to make the pressure in the air tank A reach the initial state of the next air spring or air spring group, and performs the above steps until the exhaust simulation of all air springs is completed.

[0021] As a further solution of the present invention: when simulating the inflation of multiple air springs, after one air spring or air spring group completes the inflation simulation, the controller ECU controls the solenoid valve A and the solenoid valve B to make the pressure in the air tank A reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring inflation simulations are completed.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] By performing closed-loop control on the pressure in the air tank A through the solenoid valve A, the solenoid valve B and the pressure sensor A, the pressure in the air tank A can be adjusted according to the change in the height of the air spring;

[0024] The pressure in the gas tank B is controlled in a closed loop through the solenoid valve C, the solenoid valve D and the pressure sensor B, and the pressure in the gas tank B is adjusted according to demand;

[0025] The air volume transferred by the closed air supply unit is detected by the flow sensor FS. Combined with the air spring height, volume and pressure input into the controller ECU, the transferred air volume can be converted into air spring height, which can intuitively reflect the adjustment time of different air spring heights.

[0026] The pressure of gas tank A and gas tank B is increased by opening the solenoid valve A and solenoid valve C connected to the gas source respectively, so that the gas source can quickly increase the pressure of them.

[0027] The pressure of gas tank A and gas tank B is reduced, and the solenoid valve B and solenoid valve D connected to gas tank C are opened respectively, so that the compressed air inside them is quickly discharged into gas tank C.

[0028] The compressed air in the air tank C is pumped into the air source through the compressor, keeping the air tank C at a lower pressure and ensuring the pressure reduction rate of the air tanks A and C. This solution does not need to discharge the compressed air into the atmosphere, has no exhaust noise, and reduces the waste of compressed air energy.

[0029] The present invention can simulate the working condition of the whole vehicle after the design of the air suspension system is completed, match the air spring parameters and the air tank parameters in the air suspension system, debug the closed air supply unit software, evaluate the air suspension lifting rate, and reduce the development cycle and development cost of the air suspension system.

[0030] The present invention can simulate the working conditions of a whole vehicle to carry out a durability bench test of a closed air supply unit, which is in line with the working conditions of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the closed air supply unit test bench for simulating vehicle air suspension.

[0032] Figure 2 Schematic diagram of the control module in the closed air supply unit test bench for simulating vehicle air suspension.

[0033] In the figure: solenoid valve A1, solenoid valve B2, pressure protection valve A3, air tank A4, pressure sensor A5, temperature sensor A6, filter A7, closed air supply unit 8, temperature sensor B9, flow sensor 10, pressure sensor B11, pressure protection valve B12, air tank B13, solenoid valve C14, solenoid valve D15, filter B16, check valve 17, high-pressure air source 18, compressor 19, air tank C20, pressure sensor C21. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figures 1-2 In an embodiment of the present invention, a closed air supply unit stand for simulating vehicle air suspension includes an air tank A4, an air tank B13 and an air tank C20, wherein the air tank A4 is used to simulate an air spring; the air tank B13 is used to simulate the capacity of a vehicle air tank.

[0036] The air spring interface (P3 in the figure) of the closed air supply unit 8 is connected to the output end of the air storage tank A4, and a temperature sensor A6 is connected between the closed air supply unit 8 and the air storage tank A4;

[0037] The output port (P4 in the figure) of the closed air supply unit 8 is connected to an input end of the air storage tank B13, and a temperature sensor B9 and a flow sensor 10 are connected between the closed air supply unit 8 and the air storage tank B13;

[0038] The air supply port of the closed air supply unit 8 is connected to the output end of the filter A7, and the air supply port is used for the compressor in the closed air supply unit 8 to inhale and compress air from the outside.

[0039] The input port of the gas storage tank A4 is connected to the output end (P1 in the figure) of the high-pressure gas source 18 through the solenoid valve A1, and a pressure protection valve A3 is installed between the solenoid valve A1 and the gas storage tank A4; the other output port of the gas storage tank A4 is connected to an input port of the gas storage tank C20 through the solenoid valve B2; the gas storage tank A4 is also equipped with a pressure sensor A5;

[0040] The output port of the gas tank B13 is connected to the input end of the gas tank C20 through the solenoid valve D15 (specifically, the solenoid valve B2, the solenoid valve D15 and the gas tank C20 are connected through a three-way pipe, and the specific connection method is common knowledge of technicians in this field); the other input port of the gas tank B13 is connected to the output end of the high-pressure gas source 18 through the solenoid valve C14, and a pressure protection valve B12 is installed between the gas tank B13 and the solenoid valve C14; the gas tank B13 is also equipped with a pressure sensor B11;

[0041] Another input port of the gas tank C20 is connected to the output end of the filter B16 through a one-way valve 17, and the one-way valve 17 is used to ensure that external gas can enter the gas tank C20 in one direction; (Variant: a one-way valve 17 is set between the gas tank C20 and the compressor 19 to connect the output end of the filter B16, and the one-way valve 17 is used to ensure that external gas can enter the compressor 19 in one direction) The output port of the gas tank C20 is connected to the input end of the high-pressure gas source 18 (P2 in the figure) through the compressor 19, that is, the compressor 19 is used to replenish gas into the high-pressure gas source 18 to ensure the pressure of the gas output by the high-pressure gas source 18; a pressure sensor C21 is also installed on the gas tank C20.

[0042] The solenoid valve A1, solenoid valve B2, pressure sensor A5, temperature sensor A6, closed air supply unit 8, temperature sensor B9, flow sensor 10, pressure sensor B11, solenoid valve C14, solenoid valve D15, compressor 19 and pressure sensor C21 are all electrically connected to the controller ECU.

[0043] The solenoid valve may be a two-position two-way directional control valve.

[0044] During actual use, the pressures corresponding to different loads and heights of the air spring and the volumes corresponding to different heights are input into the controller ECU according to the simulation requirements; the controller ECU calculates the pressure in the air tank A4 (air spring tank AS) according to the height position and load of the air spring, and adjusts the pressure in the air tank A4 by controlling the on and off of the solenoid valve A1 and the solenoid valve B2, while the pressure sensor A5 on the air tank A4 detects the internal pressure and feeds back to the controller ECU for closed-loop control; at the same time, the controller ECU can also detect the amount of air transferred through the closed air supply unit 8 through the flow sensor 10, convert it into the height of the air spring, and then dynamically control the pressure in the air tank A4.

[0045] During actual use, the volume of the gas tank B13 can also be input so that the controller ECU controls the volume of the gas tank B13 to change to the target volume (variation: replace the gas tank B13 to adjust its volume to the target volume); or the pressure in the gas tank B13 can be input, and the controller ECU controls the on and off of the solenoid valve C14 and the solenoid valve D15 according to the feedback from the pressure sensor B11, so that the pressure in the gas tank B13 reaches the target pressure.

[0046] During actual use, the controller ECU detects the pressure in the gas tank C20 through the pressure sensor C21. When the gas tank A4 exhausts air to the gas tank C20 by controlling the solenoid valve B2 or the gas tank B13 exhausts air to the gas tank C20 through the solenoid valve D15, when the pressure in the gas tank C20 is greater than the set pressure PH (maximum pressure), the compressor 19 runs to suck in and discharge the compressed air in the gas tank C20 into the high-pressure gas source 18. The compressor 19 adjusts the operating speed of the compressor 19 in real time according to the pressure change in the gas tank C20 to ensure that PL (minimum pressure) is less than the pressure in the gas tank C20 ≤ PH; when the solenoid valve B2 and the solenoid valve D15 are disconnected after power failure, the compressor runs until the pressure in the gas tank C20 is ≤ PL.

[0047] The initial pressure PAT1 of the air tank B13, the volume corresponding to different heights of the input air spring and the pressure corresponding to different heights and loads, the initial height of the input air spring, the load of the input air spring, the controller ECU controls the pressure in the air tank A4 and the air tank B13 to reach the initial state according to the input conditions, and the closed air supply unit 8 operates according to the control of the controller ECU.

[0048] The simulation method of the closed air supply unit bench simulating the vehicle air suspension is as follows:

[0049] Simulate the exhaust in the air spring: the controller ECU controls the compressed air pressure in the air tank B13 through the solenoid valve C14 and the solenoid valve D15, and controls the compressed air pressure in the air tank A4 according to the load and height of the air spring; the closed air supply unit 8 inhales the compressed air in the air tank A4, which is discharged after being processed by the closed air supply unit 8 and flows into the air tank B13 through the flow sensor 10; the controller ECU detects the amount of compressed air in the air tank A4 flowing through the closed air supply unit 8 through the flow sensor 10, converts it to the height of the air spring, and further controls the pressure in the air tank A4 through the solenoid valve A1 and the solenoid valve B2; until the air spring reaches the target load and height. When simulating the exhaust of multiple air springs, after one air spring or air spring group completes the exhaust simulation, the controller ECU controls the solenoid valve A1 and the solenoid valve B2 to make the pressure in the air tank A4 reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring exhaust simulations are completed.

[0050] Simulate the inflation of the air spring: the controller ECU controls the compressed air pressure in the air tank B13 through the solenoid valve C14 and the solenoid valve D15, and controls the compressed air pressure in the air tank A4 according to the load and height of the air spring; the closed air supply unit 8 inhales the compressed air in the air tank B13 that flows through the flow sensor 10, and discharges it into the air tank A4 after being processed by the closed air supply unit 8; the controller ECU detects / converts the amount of compressed air in the air tank A4 that flows through the closed air supply unit 8 through the flow sensor 10 / pressure sensor B11, converts it to the height of the air spring, and further controls the pressure in the air tank A4 through the solenoid valve A1 and the solenoid valve B2; until the air spring reaches the target load and height. When simulating the inflation of multiple air springs, after one air spring or air spring group completes the inflation simulation, the controller ECU controls the solenoid valve A1 and the solenoid valve B2 to make the pressure in the air tank A4 reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring inflation simulations are completed.

[0051] The closed air supply unit 8 is simulated to replenish air to the air tank from the outside: the controller ECU controls the volume and pressure in the air tank B13 through the solenoid valve D15 and the solenoid valve C14 according to the set volume and initial pressure of the air tank B13; the closed air supply unit 8 is running, and the outside air is sucked into the closed air supply unit 8 through the filter A7, and is discharged after being processed by the closed air supply unit 8 and enters the air tank B13 through the flow sensor 10; the controller ECU detects the pressure change in the air tank B13 through the pressure sensor B11 until the replenishment pressure is reached;

[0052] Simulate the closed air supply unit 8 to replenish air to the air spring from the outside: the controller ECU controls the pressure in the air tank B13 through the solenoid valve D15 and the solenoid valve C14 according to the set initial state of the air spring; the closed air supply unit 8 is running, and the outside air is sucked into the closed air supply unit 8 through the filter AF1, and is discharged after being processed by the closed air supply unit 8 and enters the air tank B13 through the flow sensor 10; the controller ECU detects the amount of air flowing through the air tank B13 through the flow sensor 10, converts it to the height of the air spring, and further controls the pressure in the air tank B13 through the solenoid valve D15 and the solenoid valve C14; until the air spring reaches the target load and height. When simulating the inflation of multiple air springs, after one air spring or air spring group completes the inflation simulation, the controller ECU controls the solenoid valve D15 and the solenoid valve C14 to make the pressure in the air tank B13 reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring inflation simulations are completed.

[0053] Simulate the closed air supply unit 8 to self-check the pressure in the air spring and the air tank: the closed air supply unit 8 detects the pressure of the air tank A4 and the air tank B13 to achieve self-check; choose to compare and verify the pressure detected by the closed air supply unit 8 with the test results of the pressure sensor A5 and the pressure sensor B11.

[0054] The temperature sensor A6 and the temperature sensor B9 are used to detect the gas temperature of the compressed air sucked in / exhausted by the closed air supply unit 8 and are optional components.

[0055] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A closed air supply unit stand for simulating vehicle air suspension, comprising an air tank A (4), an air tank B (13) and an air tank C (20), wherein the air tank A (4) is used to simulate an air spring; the air tank B (13) is used to simulate the volume of a vehicle air tank; The output end of the air storage tank A (4) is used to connect to the air spring interface of the closed air supply unit (8); An input end of the gas storage tank B (13) is used to connect to an output port of the closed gas supply unit (8); The input port of the gas storage tank A (4) is connected to the output end of the high-pressure gas source (18) through the solenoid valve A (1); the other output port of the gas storage tank A (4) is connected to an input port of the gas storage tank C (20) through the solenoid valve B (2); the gas storage tank A (4) is also equipped with a pressure sensor A (5); The output port of the gas storage tank B (13) is connected to the input port of the gas storage tank C (20) via a solenoid valve D (15); the other input port of the gas storage tank B (13) is connected to the output port of the high-pressure gas source (18) via a solenoid valve C (14); a pressure sensor B (11) is also installed on the gas storage tank B (13); The gas storage tank C (20) is also provided with another input port for replenishing gas; the output port of the gas storage tank C (20) is connected to the input end of the high-pressure gas source (18) through the compressor (19); and the gas storage tank C (20) is also equipped with a pressure sensor C (21).

2. The closed air supply unit stand for simulating vehicle air suspension according to claim 1, characterized in that: A pressure protection valve B (12) is installed between the gas storage tank B (13) and the solenoid valve C (14), and a pressure protection valve A (3) is installed between the solenoid valve A (1) and the gas storage tank A (4).

3. The closed air supply unit stand for simulating vehicle air suspension according to claim 1 or 2, characterized in that: A temperature sensor A (6) is connected between the closed air supply unit (8) and the air storage tank A (4), and a temperature sensor B (9) and a flow sensor (10) are connected between the closed air supply unit (8) and the air storage tank B (13).

4. The closed air supply unit stand for simulating vehicle air suspension according to claim 3, characterized in that: Another input port of the gas storage tank C (20) is connected to the output end of the filter B (16) via a one-way valve (17); or the gas storage tank C (20) and the compressor (19) are connected to the output end of the filter B (16) via a one-way valve (17).

5. The closed air supply unit stand for simulating vehicle air suspension according to claim 4, characterized in that: The solenoid valve A (1), the solenoid valve B (2), the pressure sensor A (5), the temperature sensor A (6), the closed air supply unit (8), the temperature sensor B (9), the flow sensor (10), the pressure sensor B (11), the solenoid valve C (14), the solenoid valve D (15), the compressor (19) and the pressure sensor C (21) are all electrically connected to a controller ECU.

6. A method for simulating a closed air supply unit bench for simulating vehicle air suspension as claimed in claim 5, characterized in that: The method includes simulating exhaust in the air spring, simulating inflation in the air spring, simulating the closed air supply unit (8) replenishing air to the air storage tank from the outside, simulating the closed air supply unit (8) replenishing air to the air spring from the outside, and simulating the closed air supply unit (8) self-checking the pressure in the air spring and the air storage tank, as follows: Simulate exhaust in the air spring: the controller ECU controls the compressed air pressure in the air tank B (13) through the solenoid valve C (14) and the solenoid valve D (15), and controls the compressed air pressure in the air tank A (4) according to the load and height of the air spring; the closed air supply unit (8) inhales the compressed air in the air tank A (4), which is discharged after being processed by the closed air supply unit (8) and flows into the air tank B (13) through the flow sensor (10); the controller ECU detects the amount of compressed air in the air tank A (4) flowing through the closed air supply unit (8) through the flow sensor (10), converts it to the height of the air spring, and further controls the pressure in the air tank A (4) through the solenoid valve A (1) and the solenoid valve B (2); until the air spring reaches the target load and height; Simulate the inflation of the air spring: the controller ECU controls the compressed air pressure in the air tank B (13) through the solenoid valve C (14) and the solenoid valve D (15), and controls the compressed air pressure in the air tank A (4) according to the load and height of the air spring; the closed air supply unit (8) inhales the compressed air in the air tank B (13) that flows through the flow sensor (10), and discharges it into the air tank A (4) after being processed by the closed air supply unit (8); the controller ECU detects / converts the amount of compressed air in the air tank A (4) that flows through the closed air supply unit (8) through the flow sensor (10) / pressure sensor B (11), converts it to the height of the air spring, and further controls the pressure in the air tank A (4) through the solenoid valve A (1) and the solenoid valve B (2); until the air spring reaches the target load and height; The closed air supply unit (8) is simulated to replenish air to the air tank from the outside: the controller ECU controls the volume and pressure in the air tank B (13) through the solenoid valve D (15) and the solenoid valve C (14) according to the set volume and initial pressure of the air tank B (13); the closed air supply unit (8) is running, and the outside air is sucked into the closed air supply unit (8) through the filter A (7), and is discharged after being processed by the closed air supply unit (8) and enters the air tank B (13) through the flow sensor (10); the controller ECU detects the pressure change in the air tank B (13) through the pressure sensor B (11) until the replenishing pressure is reached; The closed air supply unit (8) is simulated to supply air to the air spring from the outside: the controller ECU controls the pressure in the air tank B (13) through the solenoid valve D (15) and the solenoid valve C (14) according to the set initial state of the air spring; the closed air supply unit (8) is in operation, and the outside air is sucked into the closed air supply unit (8) through the filter AF (1), and is discharged after being processed by the closed air supply unit (8) and enters the air tank B (13) through the flow sensor (10); the controller ECU detects the amount of air flowing through the air tank B (13) through the flow sensor (10), converts it to the height of the air spring, and further controls the pressure in the air tank B (13) through the solenoid valve D (15) and the solenoid valve C (14); until the air spring reaches the target load and height; The closed air supply unit (8) is simulated to perform self-inspection on the pressure in the air spring and the air tank: the closed air supply unit (8) detects the pressure of the air tank A (4) and the air tank B (13) to achieve self-inspection; the pressure detected by the closed air supply unit (8) is selected to be compared and checked with the test results of the pressure sensor A (5) and the pressure sensor B (11).

7. The closed air supply unit stand for simulating vehicle air suspension according to claim 6, characterized in that: When simulating the exhaust of multiple air springs, after one air spring or air spring group completes the exhaust simulation, the controller ECU controls the solenoid valve A (1) and the solenoid valve B (2) to make the pressure in the air tank A (4) reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring exhaust simulations are completed.

8. The closed air supply unit stand for simulating vehicle air suspension according to claim 6, characterized in that: When simulating the inflation of multiple air springs, after one air spring or air spring group completes the inflation simulation, the controller ECU controls the solenoid valve A (1) and the solenoid valve B (2) to make the pressure in the air tank A (4) reach the initial state of the next air spring or air spring group, and performs the above steps until all air spring inflation simulations are completed.

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