A hydro-pneumatic suspension system and method for improving vehicle body pitch angle and vehicle body roll angle

Abstract

The present invention discloses a gas-oil suspension system and method for improving the pitch angle and roll angle of a vehicle body. A dual accumulator solution is adopted for highway and off-road driving to effectively reduce the suspension stiffness and improve the suspension comfort for highway and off-road driving. According to the value of the air pressure sensor behind the foot valve and the signal of the vehicle speed sensor and the angle sensor, the controller controls the switch of the suspension solenoid valve, switches the number of connected accumulators of the suspension during braking and turning, and then controls the suspension stiffness to suppress the pitch angle and roll angle of the whole vehicle. The gas-oil suspension system and method for improving the pitch angle and roll angle of a vehicle body provided by the present invention have a dual-mode independent suspension system, adapt to different road surfaces, and provide better comfort. Redundant design is adopted, and multi-point controllability is achieved to ensure that the stiffness of the suspension is controllable, and the pitch of the vehicle body is effectively improved. Locking is achieved to effectively suppress the forward tilt during braking and ensure driving safety. The turning angle is detected to improve the roll angle of the whole vehicle when the vehicle turns.

Description

Technical Field

[0001] The invention relates to an oil-gas suspension system and a method for improving the pitch angle and roll angle of a vehicle body, belonging to the technical field of suspension systems for engineering vehicles. Background Art

[0002] Most construction machinery wheeled vehicle suspensions use oil-gas suspensions, which can effectively improve the comfort and safety of vehicle driving due to their superior nonlinear elasticity, damping characteristics, and adjustable suspension height.

[0003] For off-road vehicles, the suspension performance directly affects the vehicle's driving safety, comfort and maneuverability due to the large ups and downs of the road surface. The road surface on which wheeled vehicles travel is bad, and ordinary oil-gas suspension alone cannot meet the performance requirements of the vehicle. For example, in the case of rapid start, sudden braking, and sharp turns, the center of gravity of the vehicle will change. If the vehicle leans back during rapid start, nods during braking, and tilts when turning, the ride comfort will be reduced.

[0004] The existing suspension system technical solutions have the following deficiencies:

[0005] (1) The response time of the brake pedal and the air circuit time affect the oil-gas suspension control time.

[0006] (2) The layout is complex. If it is a multi-axle vehicle, the pipeline layout will be more complicated.

[0007] (3) There are too many pipelines and the reliability is poor.

[0008] (4) Low vibration isolation rate and poor smoothness.

[0009] (5) There is no locking function and the amount of forward tilt during braking cannot be effectively suppressed.

[0010] (6) Unable to control the vehicle's roll when turning.

[0011] Therefore, designing a reliable and applicable suspension system is of great significance to improving the driving comfort and safety of the vehicle. Summary of the invention

[0012] Purpose: In order to overcome the deficiencies in the prior art, the present invention provides an oil-gas suspension system and method for improving the pitch angle and roll angle of a vehicle body.

[0013] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is:

[0014] In the first aspect, a hydro-pneumatic suspension system for improving the pitch angle and roll angle of a vehicle body includes: a rear axle gas tank, a front axle gas tank and a suspension cylinder, the rear axle gas tank and the front axle gas tank are respectively connected to the A1 port and the A2 port of a foot valve, and the B1 port and the B2 port of the foot valve are respectively connected to the first brake air chamber and the second brake air chamber.

[0015] The rodless chamber oil port of the suspension cylinder is port A, and the rod chamber oil port is port B. The A port of the suspension cylinder is connected to the first connecting pipeline connecting the oil outlet A port of the fifth solenoid valve, the oil outlet A port of the sixth solenoid valve, the oil inlet of the third solenoid valve and the oil inlet of the fourth solenoid valve through a pipeline.

[0016] The oil inlet of the fifth solenoid valve is connected to the oil outlet P of the pump.

[0017] The B port of the suspension oil cylinder is connected to the oil outlet A port of the second solenoid valve and the oil inlet of the first solenoid valve through pipelines. The oil inlet of the second solenoid valve is connected to the second connecting pipeline connecting the oil inlet of the sixth solenoid valve and the outlet of the small accumulator through a pipeline. The oil outlet of the first solenoid valve is connected to the third connecting pipeline connecting the oil outlet A port of the third solenoid valve and the outlet of the large accumulator through a pipeline.

[0018] The oil outlet A of the fourth solenoid valve is connected to the oil outlet pipeline T.

[0019] The first air pressure sensor is used to measure the air pressure at port B1 of the foot valve.

[0020] The second air pressure sensor is used to measure the air pressure at port B2 of the foot valve.

[0021] The port A of the controller is connected to the first air pressure sensor and the second air pressure sensor.

[0022] The B port of the controller is connected to the control port C of the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve respectively, and is used to control the opening and closing of the oil outlet A port and the oil inlet port of the solenoid valve.

[0023] The C port of the controller is connected to the rotation angle sensor.

[0024] The D port of the controller is connected to the vehicle speed sensor.

[0025] As a preferred solution, the hydraulic suspension pressure sensor is used to measure the hydraulic pressure of the first communication pipeline, and the B port of the controller is connected to the hydraulic suspension pressure sensor.

[0026] As a preferred solution, the number of the air pressure sensors is set to 2

[0027] As a preferred solution, the number of the rotation angle sensors is set to 2.

[0028] As a preferred solution, the number of the vehicle speed sensors is set to 4.

[0029] In a second aspect, a control method of a hydro-pneumatic suspension system for improving a vehicle body pitch angle and a vehicle body roll angle comprises the following steps:

[0030] (1) When driving on a road or off-road, the vehicle enters a non-braking and non-turning condition:

[0031] When the vehicle is on a highway or off-road road and is not braking or turning, the vehicle speed signal of the speed sensor and the driver's visual observation are collected, and the vehicle speed is calculated by the controller to obtain control signals of all solenoid valves, or the control signals of all solenoid valves are manually issued according to the driver's visual observation to control the first solenoid valve, the second solenoid valve, and the sixth solenoid valve to be in the open position; the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are controlled to be in the closed state, so as to connect the A port and the B port of the suspension cylinder with the small accumulator and the large accumulator.

[0032] (2) When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters the braking state:

[0033] When the driver steps on the brake foot valve, the gas in the front axle gas tank and the rear axle gas tank enters the B1 and B2 ports through the A1 and A2 ports of the foot valve, and then enters the first brake air chamber and the second brake air chamber through the B1 and B2 ports of the foot valve. The first brake air chamber and the second brake air chamber control the braking of the entire vehicle.

[0034] The controller detects and collects the vehicle speed signal of the vehicle speed sensor and the pressure signals of the first air pressure sensor and the second air pressure sensor, and performs calculations through the controller. When the vehicle speed of the vehicle speed sensor and any value of the pressure of the first air pressure sensor and the second air pressure sensor exceeds a certain threshold, control signals of all solenoid valves are obtained, and the first solenoid valve is controlled to be in a closed state, the second solenoid valve is controlled to be in an open state, and the sixth solenoid valve is controlled to be in an open state; the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are controlled to be in a closed state, so as to realize the connection between the small accumulator and the A port and the B port of the suspension cylinder.

[0035] (3) When the vehicle speed exceeds the speed limit threshold, the vehicle enters the braking state:

[0036] When the vehicle speed sensor detects that the vehicle speed is higher than the speed limit threshold, the gas in the front axle gas tank and the rear axle gas tank enters the B1 and B2 ports through the A1 and A2 ports of the foot valve, and enters the first brake air chamber and the second brake air chamber through the B1 and B2 ports of the foot valve. The first brake air chamber and the second brake air chamber control the braking of the entire vehicle.

[0037] The controller detects and collects the pressure signals of the first air pressure sensor and the second air pressure sensor, and performs calculations through the controller. When any pressure value of the first air pressure sensor and the second air pressure sensor exceeds a certain threshold, control signals of all solenoid valves are obtained, and the first solenoid valve is controlled to be in a closed state, the second solenoid valve is in a closed state, the sixth solenoid valve is in a closed state, the third solenoid valve is in a closed state, the fourth solenoid valve, and the fifth solenoid valve are in a closed state, so as to disconnect the A port and the B port of the small accumulator, the large accumulator and the suspension cylinder, and realize the rigid locking of the suspension cylinder.

[0038] (4) When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters the turning condition:

[0039] When the vehicle speed is less than the speed limit threshold, the driver makes an emergency turn, collects the vehicle speed signal from the vehicle speed sensor and the angle of the steering angle sensor, and calculates them through the controller to obtain control signals of all solenoid valves, controls the first solenoid valve to be in a closed state, the second solenoid valve to be in an open state, and the sixth solenoid valve to be in an open state; controls the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve to be in a closed state, so as to connect the small accumulator to the A port and the B port of the suspension cylinder.

[0040] (5) When the vehicle speed exceeds the speed limit threshold, the vehicle enters a turning condition:

[0041] When the vehicle speed is greater than the speed limit threshold, the driver makes an emergency turn and collects the angle of the steering angle sensor and the pressure signals of the first and second air pressure sensors, and performs calculations through the controller. When any value of the angle and the pressure exceeds a certain threshold, control signals of all solenoid valves are obtained to control the first solenoid valve to be in a closed state, the second solenoid valve to be in a closed state, and the sixth solenoid valve to be in a closed state; the third solenoid valve to be in a closed state, the fourth solenoid valve to be in a closed state, and the sixth solenoid valve to be in a closed state, so as to disconnect the A port and the B port of the small accumulator, the large accumulator and the suspension cylinder.

[0042] Beneficial effects: The oil-gas suspension system and method for improving the pitch angle and roll angle of the vehicle body provided by the present invention have high vibration isolation rate, good smoothness and comfortable ride. It has a dual-mode independent suspension system, which can adapt to different road surfaces and provide better comfort. It adopts redundant design and multi-point controllability to ensure the controllable stiffness of the suspension and effectively improve the pitch of the vehicle body. It realizes locking, effectively suppresses the forward tilt of the brake and ensures driving safety. It detects the turning angle and improves the roll angle of the whole vehicle when the vehicle turns. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of the oil-gas suspension system of the present invention.

[0044] Explanation of the symbols in the diagram: rear axle air tank 1, front axle air tank 2, foot valve 3, first air pressure sensor 4, first brake air chamber 5, small accumulator 6, suspension cylinder 7, large accumulator 8, first solenoid valve 9, second solenoid valve 10, hydraulic suspension pressure sensor 11, third solenoid valve 12, fourth solenoid valve 13, pump 14, fifth solenoid valve 15, sixth solenoid valve 16, vehicle speed sensor 17, controller 18, steering angle sensor 19, second air pressure sensor 20, second brake air chamber 21. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with specific embodiments.

[0046] like Figure 1 As shown, the first embodiment is an oil-gas suspension system for improving the pitch angle and roll angle of the vehicle body, comprising: a rear axle air tank 1, a front axle air tank 2 and a suspension cylinder 7, the rear axle air tank 1 and the front axle air tank 2 are respectively connected to the A1 port and the A2 port of the foot valve 3, and the B1 port and the B2 port of the foot valve 3 are respectively connected to the first brake air chamber 5 and the second brake air chamber 21.

[0047] The rodless chamber oil port of the suspension cylinder 7 is port A, and the rod chamber oil port is port B. The A port of the suspension cylinder 7 is connected to the first connecting pipeline connecting the oil outlet A port of the fifth solenoid valve 15, the oil outlet A port of the sixth solenoid valve 16, the oil inlet of the third solenoid valve 12 and the oil inlet of the fourth solenoid valve 13 through a pipeline.

[0048] The oil inlet of the fifth solenoid valve 15 is connected to the oil outlet P of the pump 14 .

[0049] The port B of the suspension oil cylinder 7 is connected to the oil outlet port A of the second solenoid valve 10 and the oil inlet port of the first solenoid valve 9 through pipelines. The oil inlet port of the second solenoid valve 10 is connected to the second connecting pipeline connecting the oil inlet port of the sixth solenoid valve 16 and the outlet of the small accumulator 6 through a pipeline. The oil outlet port A of the first solenoid valve 9 is connected to the third connecting pipeline connecting the oil outlet port A of the third solenoid valve 12 and the outlet of the large accumulator 8 through a pipeline.

[0050] The oil outlet A of the fourth solenoid valve 13 is connected to the oil outlet pipeline T.

[0051] The first air pressure sensor 4 is used to measure the air pressure at port B1 of the foot valve 3 .

[0052] The second air pressure sensor 20 is used to measure the air pressure at port B2 of the foot valve 3 .

[0053] The hydraulic suspension pressure sensor 11 is used to measure the hydraulic pressure of the first communication pipeline.

[0054] Port A of the controller 18 is connected to the first air pressure sensor 4 and the second air pressure sensor 20 .

[0055] Port B of the controller 18 is connected to the hydraulic suspension pressure sensor 11, and is also connected to the control ports C of the first solenoid valve 9, the second solenoid valve 10, the third solenoid valve 12, the fourth solenoid valve 13, the fifth solenoid valve 15 and the sixth solenoid valve 16, respectively, for controlling the opening and closing of the oil outlet A and the oil inlet of the solenoid valve.

[0056] The C port of the controller 18 is connected to the rotation angle sensor 19 .

[0057] The D port of the controller 18 is connected to the vehicle speed sensor 17 .

[0058] When the vehicle speed sensor 17 detects that the vehicle speed is higher than the threshold, the gas in the rear axle gas tank 1 and the front axle gas tank 2 enters the B1 and B2 ports through the A1 and A2 ports of the foot valve 3, and enters the first brake air chamber 5 and the second brake air chamber 21 through the B1 and B2 ports of the foot valve 3, thereby controlling the braking of the entire vehicle. At this time, the controller 18 detects and collects the vehicle speed of the vehicle speed sensor 17 and the pressure of the first air pressure sensor 4 and the second air pressure sensor 20. When the vehicle speed detected by the vehicle speed sensor 17 and the pressure of the first air pressure sensor 4 and the second air pressure sensor 20 exceed a certain threshold, the controller 18 performs calculations to control the first electromagnetic valve 9, the second electromagnetic valve 10, and the sixth electromagnetic valve 16 to close, thereby realizing the rigid switching and locking of the suspension oil cylinder 7, which has high rigidity and effectively suppresses the pitching of the entire vehicle.

[0059] By adopting an oil-gas suspension system, the suspension cylinder 7 is connected to the small accumulator 6, the large accumulator 8 and the pump 14 through the third solenoid valve 12, the fourth solenoid valve 13, the fifth solenoid valve 15, the sixth solenoid valve 16, the small accumulator 6, the large accumulator 8 and the pump 14, so as to realize the up and down displacement adjustment of the whole vehicle, and also realize the free switching of the suspension elasticity and rigidity according to the working conditions.

[0060] The braking system of the whole vehicle adopts pneumatic foot valve braking, which can realize the pneumatic braking of the whole vehicle and meet the braking distance requirements of the whole vehicle. When the brake foot valve is working, when the working condition that requires braking occurs, the foot valve is manually stepped on, and the first air pressure sensor 4 and the second air pressure sensor 20 will display the air pressure value, the brake light switch is closed, and the brake light is on, which is convenient for reminding the following vehicle.

[0061] The whole vehicle adopts dual accumulators. Different accumulators are connected to the suspension cylinder to achieve different suspension stiffness. When dual accumulators are used, the driving smoothness of the whole machine can be improved. When braking or turning conditions are required, switching to a single accumulator can increase the suspension stiffness of the whole vehicle and improve the driving stability of the whole machine.

[0062] The specific principle of improving the vehicle body pitch angle and vehicle body tilt angle is that the front axle air tank 2 and the rear axle air tank 1 provide air source for the braking system to ensure sufficient air source required for braking. When encountering working conditions requiring braking, the system automatically collects the vehicle speed sensor 17 and the first air pressure sensor 4 and the second air pressure sensor 20 signals through the controller 18 by manually stepping on the foot valve 3. Through different vehicle speed signals and air pressure sensor signals, the opening of different valve groups of the solenoid valve is controlled to control the stiffness of the suspension, which has adapted to the braking working conditions of the whole vehicle, reduced braking pitch, and improved the comfort of the whole vehicle.

[0063] By collecting the signals of the vehicle speed sensor 17 and the steering angle sensor 19, a reasonable suspension stiffness is matched to meet the turning working condition requirements of the whole vehicle, the stiffness of the suspension is controlled, the turning roll is reduced, and the comfort of the whole vehicle is improved.

[0064] A second embodiment of a method for controlling a hydro-pneumatic suspension system for improving a vehicle body pitch angle and a vehicle body roll angle comprises the following steps:

[0065] (1) When driving on a road or off-road, the vehicle enters a non-braking and non-turning condition:

[0066] When the vehicle is on a highway or off-road road and is not braking or turning, the vehicle speed signal of the speed sensor 17 and the driver's visual observation are collected, and the vehicle speed is calculated by the controller 18 to obtain the control signals of all the solenoid valves, or the control signals of all the solenoid valves are manually issued according to the driver's visual observation, so as to control the first solenoid valve 9, the second solenoid valve 10, and the sixth solenoid valve 16 to be in the open position; and control the third solenoid valve 12, the fourth solenoid valve 13, and the fifth solenoid valve 15 to be in the closed state, so as to realize the connection between the A port and the B port of the suspension cylinder 7 and the small accumulator 6 and the large accumulator 8.

[0067] At this time, the stiffness of the suspension is small, which in turn improves the smoothness of the entire vehicle and makes the driver feel more comfortable riding.

[0068] (2) When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters the braking state:

[0069] When the driver steps on the brake foot valve 3, the gas in the front axle gas tank 2 and the rear axle gas tank 1 enters the B1 and B2 ports through the A1 and A2 ports of the foot valve 3, and enters the first brake air chamber 5 and the second brake air chamber 21 through the B1 and B2 ports of the foot valve 3. The first brake air chamber 5 and the second brake air chamber 21 control the braking of the entire vehicle.

[0070] The controller 18 detects and collects the vehicle speed signal of the vehicle speed sensor 17 and the pressure signals of the first air pressure sensor 4 and the second air pressure sensor 20, and performs calculations through the controller 18. When the vehicle speed of the vehicle speed sensor 17 and any value of the pressure of the first air pressure sensor 4 and the second air pressure sensor 20 exceeds a certain threshold value, control signals of all solenoid valves are obtained, and the first solenoid valve 9 is controlled to be in a closed state, the second solenoid valve 10 is controlled to be in an open state, and the sixth solenoid valve 16 is controlled to be in an open state; the third solenoid valve 12, the fourth solenoid valve 13, and the fifth solenoid valve 15 are controlled to be in a closed state, so that the small accumulator 6 and the A port and the B port of the suspension cylinder 7 are connected.

[0071] At this time, the stiffness of the controlled suspension is increased to effectively suppress the pitch angle of the vehicle.

[0072] (3) When the vehicle speed exceeds the speed limit threshold, the vehicle enters the braking state:

[0073] When the vehicle speed sensor 17 detects that the vehicle speed is higher than the speed limit threshold, the gas in the front axle gas tank 2 and the rear axle gas tank 1 enters the B1 and B2 ports through the A1 and A2 ports of the foot valve 3, and enters the first brake air chamber 5 and the second brake air chamber 21 through the B1 and B2 ports of the foot valve 3. The first brake air chamber 5 and the second brake air chamber 21 control the braking of the entire vehicle.

[0074] The controller 18 detects and collects the pressure signals of the first air pressure sensor 4 and the second air pressure sensor 20, and performs calculations through the controller 18. When any pressure value of the first air pressure sensor 4 and the second air pressure sensor 20 exceeds a certain threshold value, control signals of all solenoid valves are obtained, and the first solenoid valve 9 is controlled to be in a closed state, the second solenoid valve 10 is in a closed state, the sixth solenoid valve 16 is in a closed state, the third solenoid valve 12 is in a closed state, the fourth solenoid valve 13, and the fifth solenoid valve 15 are in a closed state, so as to disconnect the A port and the B port of the small accumulator, the large accumulator and the suspension cylinder, and realize the rigid locking of the suspension cylinder.

[0075] At this time, the stiffness of the controlled suspension is further increased, effectively suppressing the pitch angle of the vehicle and improving the driving comfort of the vehicle.

[0076] (4) When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters the turning condition:

[0077] When the vehicle speed is less than the speed limit threshold, the driver makes an emergency turn, collects the vehicle speed signal from the vehicle speed sensor 17 and the angle of the steering angle sensor 19, and calculates them through the controller 18 to obtain control signals of all solenoid valves, controls the first solenoid valve 9 to be in a closed state, the second solenoid valve 10 to be in an open state, and the sixth solenoid valve 16 to be in an open state; controls the third solenoid valve 12, the fourth solenoid valve 13, and the fifth solenoid valve 15 to be in a closed state, so as to connect the small accumulator 6 to the A port and the B port of the suspension cylinder 7.

[0078] At this time, the stiffness of the control suspension is increased to effectively suppress the roll of the vehicle.

[0079] (5) When the vehicle speed exceeds the speed limit threshold, the vehicle enters a turning condition:

[0080] When the vehicle speed is greater than the speed limit threshold, the driver makes an emergency turn and collects the angle of the steering angle sensor 19 and the pressure signals of the first air pressure sensor 4 and the second air pressure sensor 20, and performs calculations through the controller 18. When any value of the angle and the pressure exceeds a certain threshold, control signals of all solenoid valves are obtained to control the first solenoid valve 9 to be in a closed state, the second solenoid valve 10 to be in a closed state, and the sixth solenoid valve 16 to be in a closed state; the third solenoid valve 12 to be in a closed state, the fourth solenoid valve 13 to be in a closed state, and the sixth solenoid valve 15 to be in a closed state, so as to disconnect the A port and the B port of the small accumulator 6, the large accumulator 8 and the suspension cylinder 7, and realize the rigid locking of the suspension cylinder.

[0081] At this time, the rigidity of the suspension cylinder 7 is locked, thereby increasing the rigidity of the suspension and effectively suppressing the roll of the entire vehicle.

[0082] The present invention provides an oil-gas suspension system and control method for improving the pitch angle and roll angle of the vehicle body. A dual accumulator solution is used when driving on the road and off-road, which effectively reduces the suspension stiffness and improves the suspension comfort when driving on the road and off-road. According to the value of the air pressure sensor behind the foot valve and the signal of the vehicle speed sensor and the angle sensor, the controller controls the switch of the suspension solenoid valve, switches the number of connected accumulators of the suspension when braking and turning, and then controls the suspension stiffness to suppress the pitch angle and roll angle of the whole vehicle. The specific advantages are as follows:

[0083] (1) It can adapt to the high smoothness and comfort of different road surfaces, meet the requirements of highway and off-road roads, and ensure the high smoothness and comfort of the whole vehicle.

[0084] (2) Redundant design, safer and more reliable. By detecting the pressure of the air pressure sensor, the angle of the angle sensor and the design of the vehicle speed sensor, there are 2 air pressure sensors, 2 angle sensors and 4 vehicle speed sensors. The redundant design can control the oil and gas suspension and locking, with high safety and reliability.

[0085] (3) Realize the adjustment and locking of stiffness, effectively improve the pitch angle and roll angle of the vehicle body, and ensure driving safety and comfort.

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hydro-pneumatic suspension system with improved vehicle body pitch angle and vehicle body roll angle, comprising: The rear axle gas tank, the front axle gas tank and the suspension oil cylinder are characterized in that the rear axle gas tank and the front axle gas tank are connected to the A1 port and the A2 port of the foot valve respectively, and the B1 port and the B2 port of the foot valve are connected to the first brake air chamber and the second brake air chamber respectively; The rodless chamber oil port of the suspension oil cylinder is port A, and the rod chamber oil port is port B. The port A of the suspension oil cylinder is connected to the first connecting pipeline connecting the oil outlet port A of the fifth solenoid valve, the oil outlet port A of the sixth solenoid valve, the oil inlet port of the third solenoid valve, and the oil inlet port of the fourth solenoid valve through a pipeline; The oil inlet of the fifth solenoid valve is connected to the oil outlet P of the pump; The B port of the suspension oil cylinder is connected to the oil outlet A port of the second solenoid valve and the oil inlet of the first solenoid valve through pipelines respectively; the oil inlet of the second solenoid valve is connected to the second connecting pipeline connecting the oil inlet of the sixth solenoid valve and the outlet of the small accumulator through a pipeline; the oil outlet of the first solenoid valve is connected to the third connecting pipeline connecting the oil outlet A port of the third solenoid valve and the outlet of the large accumulator through a pipeline; The oil outlet A of the fourth solenoid valve is connected to the oil outlet pipeline T; The first air pressure sensor is used to measure the air pressure at port B1 of the foot valve; The second air pressure sensor is used to measure the air pressure at port B2 of the foot valve; Port A of the controller is connected to the first air pressure sensor and the second air pressure sensor; The B port of the controller is connected to the control port C of the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve respectively, and is used to control the opening and closing of the oil outlet A port and the oil inlet port of the solenoid valve; The C port of the controller is connected to the rotation angle sensor; The D port of the controller is connected to the vehicle speed sensor.

2. The oil-gas suspension system for improving the vehicle body pitch angle and vehicle body roll angle according to claim 1, characterized in that: It also includes a hydraulic suspension pressure sensor, which is connected to the first communication pipeline, and the B port of the controller is also connected to the hydraulic suspension pressure sensor.

3. The oil-gas suspension system for improving the vehicle body pitch angle and vehicle body roll angle according to claim 1, characterized in that: The number of air pressure sensors is set to 2.

4. The oil-gas suspension system for improving the vehicle body pitch angle and vehicle body roll angle according to claim 1, characterized in that: The number of the rotation angle sensors is set to 2.

5. The oil-gas suspension system for improving the vehicle body pitch angle and vehicle body roll angle according to claim 1, characterized in that: The number of the vehicle speed sensors is set to 4.

6. The control method of the oil-gas suspension system according to any one of claims 1 to 5, characterized in that: The steps include: When driving on a highway or off-road surface, the vehicle enters a non-braking and non-turning condition, collects the vehicle speed signal from the vehicle speed sensor, calculates the vehicle speed through the controller to obtain control signals of all solenoid valves, controls the first solenoid valve, the second solenoid valve, and the sixth solenoid valve to be in the open position; controls the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve to be in the closed state, and realizes the connection between the A port and the B port of the suspension cylinder and the small accumulator and the large accumulator.

7. The control method according to claim 6, characterized in that: Also includes: When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters the braking condition. When the brake foot valve is pressed, the gas in the front axle gas tank and the rear axle gas tank enters the B1 and B2 ports through the A1 and A2 ports of the foot valve, and enters the first brake air chamber and the second brake air chamber through the B1 and B2 ports of the foot valve. The first brake air chamber and the second brake air chamber control the braking of the entire vehicle. The controller detects and collects the vehicle speed signal of the vehicle speed sensor and the pressure signals of the first air pressure sensor and the second air pressure sensor, and performs calculations through the controller. When the vehicle speed of the vehicle speed sensor and any value of the pressure of the first air pressure sensor and the second air pressure sensor exceeds a certain threshold, control signals of all solenoid valves are obtained, and the first solenoid valve is controlled to be in a closed state, the second solenoid valve is controlled to be in an open state, and the sixth solenoid valve is controlled to be in an open state; the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are controlled to be in a closed state, so as to realize the connection between the small accumulator and the A port and the B port of the suspension cylinder.

8. The control method according to claim 7, characterized in that: Also includes: When the vehicle speed is greater than the speed limit threshold, the vehicle enters the braking condition. When the brake foot valve is pressed, the gas in the front axle gas tank and the rear axle gas tank enters the B1 and B2 ports through the A1 and A2 ports of the foot valve, and enters the first brake air chamber and the second brake air chamber through the B1 and B2 ports of the foot valve. The first brake air chamber and the second brake air chamber control the braking of the entire vehicle. The controller detects and collects the pressure signals of the first air pressure sensor and the second air pressure sensor, and performs calculations through the controller. When any pressure value of the first air pressure sensor and the second air pressure sensor exceeds a certain threshold, control signals of all solenoid valves are obtained, and the first solenoid valve is controlled to be in a closed state, the second solenoid valve is in a closed state, the sixth solenoid valve is in a closed state, the third solenoid valve is in a closed state, the fourth solenoid valve, and the fifth solenoid valve are in a closed state, so as to disconnect the A port and the B port of the small accumulator, the large accumulator and the suspension cylinder, and realize the rigid locking of the suspension cylinder.

9. The control method according to claim 8, characterized in that: Also includes: When the vehicle speed is less than or equal to the speed limit threshold, the vehicle enters a turning condition, collects the vehicle speed signal of the speed sensor and the angle of the steering angle sensor, and calculates through the controller to obtain control signals of all solenoid valves, controls the first solenoid valve to be in a closed state, the second solenoid valve to be in an open state, and the sixth solenoid valve to be in an open state; controls the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve to be in a closed state, so as to connect the small accumulator to the A port and the B port of the suspension cylinder.

10. The control method according to claim 9, characterized in that: Also includes: When the vehicle speed is greater than the speed limit threshold, the vehicle enters a turning condition, collects the angle of the steering angle sensor and the pressure signals of the first and second air pressure sensors, and performs calculations through the controller. When any value of the angle and the pressure exceeds a certain threshold, control signals of all solenoid valves are obtained to control the first solenoid valve to be in a closed state, the second solenoid valve to be in a closed state, and the sixth solenoid valve to be in a closed state; the third solenoid valve to be in a closed state, the fourth solenoid valve to be in a closed state, and the sixth solenoid valve to be in a closed state, so as to disconnect the A and B ports of the small accumulator, the large accumulator and the suspension cylinder.

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