Electromagnetic balanced vehicle hydraulic suspension system and control method thereof

Abstract

The invention discloses an electromagnetic balanced vehicle hydraulic suspension system and a control method thereof. The control method comprises the following steps: when the vehicle starts, firstly, the vehicle speed signal is judged. When the vehicle speed signal is zero, the vehicle body posture information and oil pressure information, such as the signal of the vehicle body tilt angle sensor and the signal of the oil pressure sensor, are judged. If the left and right tilt angles are within the set range, and / or the oil pressure difference is within the set range, it indicates that the vehicle is parked on a horizontal road surface; when it is judged that the vehicle is parked on a horizontal road surface, a signal is sent from a central processing unit to an electromagnetic switch valve, which is automatically closed after being kept open for n seconds, and the electromagnetic switch valve is used to realize the rapid connection and isolation of the oil in the hydraulic circuits on the left and right sides of the hydraulic suspension. The opening and closing of the electromagnetic valve is controlled to realize the interconnection of the two hydraulic circuits, solve the pressure difference problem of the set working pressure of the two oil circuits caused by wear and leakage, and ensure that the hydraulic interconnection suspension system is in the best performance.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle hydraulic suspension, and in particular to an electromagnetically balanced vehicle hydraulic suspension system and a control method thereof. Background Art

[0002] With the continuous development of the automobile industry, the safety, handling stability and comfort of automobiles are receiving more and more attention from customers. The existing mainstream traditional suspension forms are mostly elastic elements matched with lateral stabilizer bars. The elastic elements include leaf springs, coil springs or airbag springs. The lateral stabilizer bar can only provide linear stiffness. If a certain handling stability is to be met, the lateral stabilizer bar needs to be made thicker, which will have a significant negative impact on the smoothness of the vehicle. Therefore, vehicles that use leaf springs or coil springs as elastic elements generally have the problem of poor smoothness; vehicles that use airbags as elastic elements, especially in vehicles, sacrifice some handling stability in order to meet smoothness.

[0003] At the same time, the requirements for the rollover safety of various types of vehicles, that is, the lateral stability of the vehicle itself, are gradually increasing. In order to improve the roll stability of the vehicle, the stiffness of the suspension is generally increased or a lateral stabilizer bar is installed. However, when the suspension stiffness is increased or the lateral stabilizer bar is thickened, while the suspension roll stiffness is increased, it will have a negative impact on the vehicle's ride comfort, that is, the lateral stability of the vehicle is improved but the ride comfort of the vehicle is reduced. Therefore, there is a compromise between lateral stability and ride comfort in traditional suspension design, and it is impossible to achieve the best of both at the same time. At the same time, once the model and size parameters of the lateral stabilizer bar are determined, it can only provide a fixed linear stiffness, and cannot adaptively provide different stiffness values ​​according to changes in the vehicle's driving conditions. This defect further limits the improvement of vehicle comfort.

[0004] Based on the above problems, hydraulic suspension systems are currently mostly used for improvement. The system can improve the handling stability of the vehicle without affecting the smoothness of the vehicle; such as a passive hydraulic interconnected suspension system disclosed in Chinese Patent 201420153588.X; the system is composed of components such as hydraulic cylinders, hydraulic pipelines, accumulators and damping valves; the hydraulic cylinders are arranged between the four wheels and the vehicle body, one end is fixed to the vehicle body, and the other end is fixed to the wheel, and the four hydraulic cylinders are interconnected in a certain way to form two closed hydraulic circuits, each closed circuit is equipped with at least one accumulator, and at least one device for providing damping is set or not set.

[0005] However, in actual engineering applications, as the hydraulic components of the above-mentioned passive hydraulic interconnected suspension system work for a long time, especially the seals used in the hydraulic components, they will wear out, resulting in reduced sealing performance, which will cause oil leakage in the hydraulic components. If the wear conditions of the hydraulic components in the two hydraulic circuits are different, the oil leakage in the two circuits may be different, which will cause a pressure difference between the two circuits; this pressure difference will affect the performance of the hydraulic interconnected suspension system; and due to changes in factors such as temperature, the oil volume in the system will change, which will further increase the pressure difference between the two circuits, thereby causing changes in the body posture. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides an electromagnetically balanced vehicle hydraulic suspension system and a control method thereof, which can effectively solve the pressure difference problem of setting working pressures of different oil circuits caused by wear and leakage, etc., and ensure that the hydraulic interconnected suspension system is at optimal performance.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] An electromagnetically balanced vehicle hydraulic suspension system, comprising:

[0009] The front left hydraulic cylinder, front right hydraulic cylinder, rear left hydraulic cylinder and rear right hydraulic cylinder of the suspension, the rodless chamber of the front left hydraulic cylinder, the rod chamber of the front right hydraulic cylinder, the rodless chamber of the rear left hydraulic cylinder and the rod chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P1; the rod chamber of the front left hydraulic cylinder, the rodless chamber of the front right hydraulic cylinder, the rod chamber of the rear left hydraulic cylinder and the rodless chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P2;

[0010] Accumulator, hydraulic circuit P1 and hydraulic circuit P2 are both connected with accumulators;

[0011] The electromagnetic switch valve is used to realize the interconnection of the two hydraulic circuits. The electromagnetic switch valve is arranged between the hydraulic circuit P1 and the hydraulic circuit P2;

[0012] The central processing unit is used to control the operation of the electromagnetic switch valve, and the central processing unit is connected to the electromagnetic switch valve.

[0013] It also includes a vehicle body posture sensor, which is connected to the central processing unit.

[0014] Each hydraulic circuit is provided with an oil pressure sensor, and the oil pressure sensor is connected to the central processing unit.

[0015] A damping valve structure is provided at the port corresponding to each hydraulic cylinder and between the accumulator and the corresponding hydraulic circuit. The damping valve structure is a fixed-resistance damping valve or an adjustable damping valve. If it is an adjustable damping valve, the adjustable damping valve is connected to the central processing unit.

[0016] The electromagnetic switch valve is an on-off electromagnetic valve, and the electromagnetic switch valve is an electromagnetic needle valve, an electromagnetic slide valve, or an electromagnetic rotary valve.

[0017] The hydraulic cylinder is located between the wheel and the body of the vehicle, and an elastic element is provided corresponding to the hydraulic cylinder. The hydraulic cylinder and the elastic element work in parallel to support the body.

[0018] The electromagnetic switch valve is a normally closed valve.

[0019] There are more than two body posture sensors, which are respectively arranged on both sides of the vehicle.

[0020] The vehicle body posture sensor is a displacement sensor, a height sensor, or a vehicle body inclination sensor.

[0021] A control method for an electromagnetically balanced vehicle hydraulic suspension system comprises the following steps:.

[0022] S1: When the vehicle starts, the vehicle speed signal is first determined. When the vehicle speed signal is zero, the vehicle body posture information and oil pressure information are determined, such as the signal of the vehicle body inclination sensor and the signal of the oil pressure sensor. If the left and right inclination angles are within the set range, and / or the oil pressure difference is within the set range, it indicates that the vehicle is parked on a horizontal road surface;

[0023] S2: If the vehicle is judged to be parked on a horizontal road, the central processing unit sends a signal to the electromagnetic switch valve, which remains open for n seconds and then closes automatically. The electromagnetic switch valve is used to quickly connect and disconnect the oil in the hydraulic circuits on the left and right sides of the hydraulic suspension.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The electromagnetic balanced vehicle hydraulic suspension system and its control method are reasonably designed. A switch-type solenoid valve is set between the hydraulic suspension circuits on both sides. A vehicle body posture sensor and a central processor are added at the same time. The opening and closing of the solenoid valve can be controlled according to the vehicle body posture signal under specific working conditions, so as to realize the interconnection of the two hydraulic circuits, solve the pressure difference problem of the set working pressure of the two oil circuits caused by wear and leakage, and ensure that the hydraulic interconnected suspension system is in optimal performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following is a brief description of the contents and symbols in the drawings of this specification:

[0027] Figure 1 A schematic diagram of an embodiment of the present invention.

[0028] Figure 2 It is a schematic diagram of another embodiment of the present invention.

[0029] Figure 3 This is the logic diagram of the opening and closing control of the solenoid valve of the present invention.

[0030] Figure 4 for Figure 2 Control logic diagram of the adjustable damping valve in the embodiment.

[0031] In the figure:

[0032] C1: Front left hydraulic cylinder

[0033] C2: Front right hydraulic cylinder

[0034] C3: Rear left hydraulic cylinder

[0035] C4: Rear right hydraulic cylinder

[0036] D11, D12: front left hydraulic cylinder upper chamber damping valve, front left hydraulic cylinder lower chamber damping valve

[0037] D21, D22: front right hydraulic cylinder upper chamber damping valve, front right hydraulic cylinder lower chamber damping valve

[0038] D31, D32: Damping valve of the upper chamber of the rear left hydraulic cylinder, damping valve of the lower chamber of the rear left hydraulic cylinder

[0039] D41, D42: Damping valve of the upper chamber of the rear right hydraulic cylinder, damping valve of the lower chamber of the rear right hydraulic cylinder

[0040] Da1, Da2: left accumulator damping valve, right accumulator damping valve

[0041] A1, A2: left accumulator, right accumulator

[0042] p1, p2: left hydraulic circuit, right hydraulic circuit

[0043] S1, S2: left circuit oil pressure sensor, right circuit oil pressure sensor

[0044] V: Solenoid switch valve

[0045] E: CPU

[0046] S: Body posture sensor

[0047] d11, d12: Adjustable damping valves in the upper and lower chambers of the front left hydraulic cylinder

[0048] d21, d22: Adjustable damping valves in the upper and lower chambers of the front right hydraulic cylinder

[0049] d31, d32: Adjustable damping valves in the upper and lower chambers of the rear left hydraulic cylinder

[0050] d41, d42: Adjustable damping valves in the upper and lower chambers of the rear right hydraulic cylinder

[0051] da1, da2: left accumulator adjustable damping valve, right accumulator adjustable damping valve. DETAILED DESCRIPTION

[0052] The specific implementation modes of the present invention will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0053] like Figures 1 to 4 As shown, the electromagnetic balanced vehicle hydraulic suspension system includes a front left hydraulic cylinder, a front right hydraulic cylinder, a rear left hydraulic cylinder, a rear right hydraulic cylinder, an accumulator, an electromagnetic switch valve, a vehicle body posture sensor and a central processing unit.

[0054] The rodless chamber of the front left hydraulic cylinder, the rod chamber of the front right hydraulic cylinder, the rodless chamber of the rear left hydraulic cylinder and the rod chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P1; the rod chamber of the front left hydraulic cylinder, the rodless chamber of the front right hydraulic cylinder, the rod chamber of the rear left hydraulic cylinder and the rodless chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P2; both the hydraulic circuit P1 and the hydraulic circuit P2 are connected to accumulators.

[0055] The electromagnetic switch valve is used to realize the interconnection of the two hydraulic circuits. The electromagnetic switch valve is set between the hydraulic circuit P1 and the hydraulic circuit P2. The central processor is used to control the operation of the electromagnetic switch valve. The central processor is connected to the electromagnetic switch valve. The body posture sensor is used to detect the vehicle posture. The body posture sensor is connected to the central processor. Each hydraulic circuit is equipped with an oil pressure sensor, which is connected to the central processor.

[0056] In the present invention, a switch-type solenoid valve is arranged between the hydraulic suspension circuits on both sides, and a vehicle body posture sensor and a central processing unit are added at the same time, so that the opening and closing of the solenoid valve can be controlled according to the vehicle body posture signal under specific working conditions, thereby realizing the interconnection of the two hydraulic circuits, solving the pressure difference problem of the set working pressure of the two oil circuits caused by wear and leakage, and ensuring that the hydraulic interconnected suspension system is in optimal performance.

[0057] The hydraulic cylinder is the actuating element in this scheme, which includes two upper and lower connecting parts, at least two oil ports, a cylinder barrel, and a piston rod. The hydraulic cylinder is located between the wheel and the body, with one connecting part fixed to the body and the other connecting part fixed to the wheel. The hydraulic cylinder can partially bear the load of the body. At this time, the hydraulic cylinder works in parallel with the elastic element; the hydraulic cylinder can also bear all the load of the body. At this time, the hydraulic cylinder and the hydraulic circuit system containing the accumulator replace the elastic element, and elastic elements such as leaf springs, coil springs or airbags are no longer needed. However, in this case, the load-bearing capacity of the hydraulic cylinder is required to be higher. This case takes the hydraulic cylinder and the elastic element working in parallel as an example. When matching with the vehicle, the number of hydraulic cylinders is matched according to the vehicle suspension structure and performance requirements. This case takes the common two-axle vehicle with two front and two rear hydraulic cylinders as an example to illustrate. For the system of multi-axle vehicles, the same can be applied.

[0058] The upper and lower connecting parts of the hydraulic cylinder can be in the form of lifting ears, forks or struts. The hydraulic cylinder contains at least two oil ports, which are connected to the upper and lower chambers of the hydraulic cylinder respectively. The cylinder barrel of the hydraulic cylinder is fixed to the upper end connection part, and the fixing form can be welding, threaded connection or other connection forms. The upper part of the piston rod is equipped with a piston, which is located inside the cylinder barrel, and the cylinder barrel is divided into two cavities: a rodless chamber and a rod chamber. According to the examples shown in this case, they can be called upper chamber and lower chamber. The middle part is sealed with the cylinder barrel by a seal, and the seal slides along the inner wall of the cylinder barrel. The lower part of the piston rod is fixed to the lower end connection part.

[0059] The damping valve is set at a single oil port or multiple oil ports of the hydraulic cylinder to provide the damping force of vertical shock absorption required by the system. As needed, the damping valve can also be set at the outlet of the accumulator to provide damping force in the pipeline before the accumulator, and the size of the roll damping force can be adjusted. The damping valve can be a lamella valve or a small hole valve with a fixed damping force, or an adjustable damping valve with adjustable flow; if it is an adjustable damping valve, each of its adjustable damping valves is connected to the central processing unit. The adjustable damping valve can be an independent valve to achieve flow control, or it can be a valve system combination, such as a combination of a lamella valve and a small hole valve with controllable flow, or a combination of a small hole valve with a fixed flow and a small hole valve with controllable flow.

[0060] The accumulators are divided into two circuits. The accumulators can be diaphragm type, bladder type, piston type, metal bellows type or other forms. As long as they can store gas at one end and liquid at the other end, they are within the scope of this case. The gas in the accumulator is an inert gas, such as nitrogen. As needed, there can be one or more accumulators in each circuit. This case is explained by taking one accumulator in each circuit as an example.

[0061] Hydraulic pipes and hydraulic pipe joints provide oil circulation channels and need to ensure a certain pressure bearing capacity and the ability to seal oil. The connection between hydraulic pipes and hydraulic pipe joints, as well as hydraulic cylinders, accumulators and damping valves can be threaded, flanged or welded. As long as there is no oil leakage after connection, it is within the scope of protection of this case. The sealing method can be a general form of O-ring sealing, gasket sealing or combined gasket sealing. As long as it can achieve a sealing effect, it is within the scope of protection of this case.

[0062] The electromagnetic switch valve can be a needle valve, a slide valve or a rotary valve, etc. As long as it can realize the connection and disconnection of the connection circuit, it is within the protection scope of this case. The electromagnetic switch valve is controlled by the central processor and powered on. The electromagnetic switch valve is a normally closed valve. It is always closed during the vehicle driving, and the two hydraulic circuits are disconnected at this time. It will only be triggered to open when the vehicle is stationary and parked on a long horizontal straight road. At this time, the two hydraulic circuits are connected, and according to the settings in the control logic, it will automatically close after a certain period of connection.

[0063] The central processing unit integrates the control strategy of the electromagnetic switch valve and the control strategy of the adjustable damping valve. By receiving the signal transmitted by the vehicle sensor, according to the control strategy, it sends instructions to the electromagnetic switch valve and the adjustable damping valve to realize the opening and closing of the electromagnetic switch valve, or the adjustment of the damping aperture size of the adjustable damping valve.

[0064] The body posture sensor can be a displacement sensor, a height sensor, or a body inclination sensor. As long as it can obtain the position change signal of the left and right or front and back of the body relative to the initial horizontal position, it is within the protection scope of this case. Generally, vehicles are equipped with various sensors. In this case, it is only necessary to export the required body posture signal from the CAN bus to the central processing. If the vehicle does not contain such sensors, such sensors can be installed on the vehicle to obtain the required signals. This type of sensor technology is mature, low-priced, and easy to use. This case uses the inclination sensor as an example to illustrate.

[0065] Oil pressure sensors are respectively arranged in two hydraulic system circuits to monitor the real-time pressure levels of the two hydraulic system circuits.

[0066] like Figure 1 The figure shows the connection diagram of the electromagnetic switch type hydraulic suspension system matched with the vehicle. The upper chamber of the left hydraulic cylinder of the front axle is connected to the lower chamber of the right hydraulic cylinder of the front axle, and the lower chamber of the left hydraulic cylinder of the front axle is connected to the upper chamber of the right hydraulic cylinder of the front axle; the upper chamber of the left hydraulic cylinder of the rear axle is connected to the lower chamber of the right hydraulic cylinder of the rear axle, and the lower chamber of the left hydraulic cylinder of the rear axle is connected to the upper chamber of the right hydraulic cylinder of the rear axle; the upper chamber of the hydraulic cylinder of the front axle and the rear axle are connected to the upper chamber, and the lower chamber is connected to the lower chamber. Thus, two hydraulic circuits are formed.

[0067] In order to meet the requirements of vehicle smoothness and handling stability, after installing the hydraulic suspension system in this case, the stiffness of the leaf spring or airbag working in parallel with the hydraulic cylinder can be appropriately reduced, and the lateral stabilizer bar can be removed. At this time, the hydraulic suspension system can be relied on to provide part of the vertical stiffness required by the whole vehicle, as well as the roll stiffness that plays a major role. At the same time, since the hydraulic suspension system in this case has its oil pressure change in real time with the vehicle body posture and road conditions, it can achieve real-time changes in vertical stiffness and roll stiffness.

[0068] When the vehicle is traveling on a flat road, the piston rod of the hydraulic cylinder is in a high-frequency, small-amplitude fluctuation state, and the oil flows through the damping valve, with a small amount entering and exiting the accumulator. At this time, the roll stiffness provided by the system is small, and it mainly provides part of the vertical stiffness. Relying on the damping valve and the bushing at the connection between the hydraulic cylinder and the vehicle body, the vertical vibration can be quickly absorbed to ensure that the vehicle's body posture is stable and smooth.

[0069] When the vehicle turns or changes lanes quickly, the piston rod of the hydraulic cylinder on one side is compressed, and the piston rod of the hydraulic cylinder on the other side is stretched. The piston rod is in a low-frequency and large-amplitude motion state, and a large amount of oil flows through the damping valve and enters and exits the accumulator. The accumulator gas in the hydraulic circuit on the side where the piston rod is compressed is compressed, the pressure increases, and the oil pressure in the circuit increases, generating a force to suppress the compression of the piston rod; the accumulator in the hydraulic circuit on the side where the piston rod is stretched expands, the pressure decreases, and the oil pressure in the circuit decreases, generating a force to suppress the stretching of the piston rod. The forces on both sides form a torque to resist the roll of the vehicle body, which is dedicated to reducing the roll angle of the vehicle body and keeping the body posture stable. The greater the turning range of the vehicle, the greater the force generated on one side, and the greater the torque to resist the lateral roll. That is, the hydraulic system provides the required roll torque in real time according to the vehicle condition to achieve adaptive adjustment.

[0070] The control method of this system is:

[0071] During the above driving process, the electromagnetic switch valve is in a normally closed state, and the two hydraulic circuits are disconnected. When the vehicle starts, the vehicle speed signal is first judged. When the vehicle speed signal is zero, the vehicle body posture information and oil pressure information are judged, such as the signal of the vehicle body tilt sensor and the signal of the oil pressure sensor. If the left and right tilt angles are within the set range, and / or the oil pressure difference is within the set range, indicating that the vehicle is parked on a horizontal road, the central processor sends a signal to the electromagnetic switch valve, which remains open for n seconds and then automatically closes. That is, the rapid connection and disconnection of the oil in the two hydraulic circuits is achieved.

[0072] Preferred specific examples are:

[0073] Figure 1 A preferred embodiment of the present invention is as follows:

[0074] The hydraulic suspension system of the present invention comprises a front left hydraulic cylinder C1, a front right hydraulic cylinder C2, a rear left hydraulic cylinder C3, a rear right hydraulic cylinder C4, a left accumulator A1, a right accumulator A2, damping valves D11, D12, D21, D22, D31, D32, D41 and D42 in the pipeline, damping valves Da1 and Da2 in front of the accumulator, oil pressure sensors S1 and S2 in the system circuit, an electromagnetic switch valve V, a central processor E and a sensor S. A left hydraulic circuit p1 and a right hydraulic circuit p2.

[0075] When the vehicle is stationary and on a flat road, the oil in the two hydraulic circuits of the hydraulic suspension system is quickly switched on and off to eliminate the oil pressure difference in the two hydraulic circuits. The specific control logic is: when the vehicle starts, the start signal is transmitted to the central processor, and then the vehicle speed is judged. When the vehicle speed is not zero, the solenoid valve remains closed, and the central processor does not issue a command at this time. When the speed is zero, the body inclination angle and the oil pressure sensor signal in the system are judged. If the left and right inclination angles of the body are greater than the set value α, or the pressure difference of the oil pressure sensors on both sides is greater than the set value β, the solenoid valve remains closed, and the central processor does not issue a command at this time. When the body inclination angle is less than or equal to the set value α, and the oil pressure difference on both sides is less than or equal to the set value β, the central processor sends a command to open the solenoid valve. Then the time counting starts. When the opening time increases from 0 and does not reach the set value m, and the vehicle speed remains zero, the solenoid valve remains open, and the central processor does not issue a command. If the timing time does not reach the set value m and the vehicle speed is not zero, the central processor issues a command and the solenoid valve closes. When the timing reaches the set value m, the central processing unit sends an instruction to close the solenoid valve.

[0076] When the vehicle is not stationary and / or not on a straight road, the solenoid valve is in a normally closed state and the two circuits of the hydraulic suspension system are disconnected. At this time, under the external road excitation, the hydraulic suspension system will produce corresponding stiffness and damping to meet the requirements of handling stability and comfort.

[0077] At this time, taking the vehicle turning right as an example, due to the influence of centrifugal force and vehicle inertia, the vehicle body will tilt to the left. At this time, the relative distance between the left side of the vehicle and the wheel decreases, and the relative distance between the right side of the vehicle and the wheel increases, that is, the elastic element and hydraulic cylinder on the left are compressed, and the elastic element and hydraulic cylinder on the right are stretched. The piston rod of the left hydraulic cylinder moves upward, the volume of the upper chamber decreases, and the oil flows out of the upper chamber, through the hydraulic circuit, and flows into the left circuit accumulator; at the same time, the piston rod of the right hydraulic cylinder moves downward, the volume of the lower chamber decreases, and the oil flows out of the lower chamber, through the hydraulic circuit, and flows into the left circuit accumulator. The volume of oil in the left circuit accumulator increases, the gas is compressed, and the air pressure increases, resulting in an increase in the oil pressure of the left circuit. Correspondingly, the pressure of the upper chamber of the left hydraulic cylinder and the lower chamber of the right hydraulic cylinder connected to the left circuit increases, generating a force to resist the continued movement of the piston rod.

[0078] At the same time, as the piston rod of the left hydraulic cylinder moves upward and the piston rod of the right hydraulic cylinder moves downward, the volume of the lower chamber of the left hydraulic cylinder and the upper chamber of the right hydraulic cylinder increases, causing the oil in the right circuit to flow out from the right circuit accumulator to replenish the lower chamber of the left hydraulic cylinder and the upper chamber of the right hydraulic cylinder, increasing their pressure and generating a force to resist the continued movement of the piston rod.

[0079] The force generated by the two circuits forms a torque, which acts on the vehicle body through the hydraulic cylinder, reducing the roll angle of the vehicle body and keeping the vehicle body posture stable.

[0080] In addition, when the vehicle is traveling on a flat random road, the piston rod of the hydraulic cylinder is in a high-frequency, small-amplitude fluctuation state, and the oil flows through the damping valve, and the amount of oil entering and exiting the accumulator is small. At this time, the roll stiffness provided by the system is small, and it mainly provides part of the vertical stiffness. Relying on the damping valve and the bushing at the connection between the hydraulic cylinder and the body, the vertical vibration can be quickly absorbed to ensure that the body posture of the bus is stable and the smoothness is good.

[0081] Figure 2 Another preferred embodiment of the present invention is as follows:

[0082] and Figure 1 The difference is that the damping valve in this embodiment is an adjustable damping valve. Figure 4 The execution strategy of the adjustable damping valve. The adjustable damping valve is controlled by the central processor. According to different driving conditions, the sensor receives the signal and transmits it to the central processor. After analysis, the central processor selects the execution strategy and transmits it to the adjustable damping valve of the hydraulic suspension system to adjust the flow in the pipeline system, thereby achieving damping adjustment.

[0083] The sensor signal can be obtained from the vehicle CAN bus, or an additional sensor can be installed. The present invention uses an adjustable damping valve to ensure further improvement of riding comfort, while optimizing the vehicle's rear followability, passability, etc.

[0084] The above is only an explanation of the preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0085] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A control method for an electromagnetically balanced vehicle hydraulic suspension system, characterized in that: The electromagnetic balanced vehicle hydraulic suspension system comprises: The front left hydraulic cylinder, front right hydraulic cylinder, rear left hydraulic cylinder and rear right hydraulic cylinder of the suspension, the rodless chamber of the front left hydraulic cylinder, the rod chamber of the front right hydraulic cylinder, the rodless chamber of the rear left hydraulic cylinder and the rod chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P1; the rod chamber of the front left hydraulic cylinder, the rodless chamber of the front right hydraulic cylinder, the rod chamber of the rear left hydraulic cylinder and the rodless chamber of the rear right hydraulic cylinder are connected to form a hydraulic circuit P2; Accumulator, hydraulic circuit P1 and hydraulic circuit P2 are both connected with accumulators; The electromagnetic switch valve is used to realize the interconnection of the two hydraulic circuits. The electromagnetic switch valve is arranged between the hydraulic circuit P1 and the hydraulic circuit P2; A central processing unit is used to control the operation of the electromagnetic switch valve, and the central processing unit is connected to the electromagnetic switch valve; It also includes a body posture sensor, which is connected to the central processing unit; each hydraulic circuit is provided with an oil pressure sensor, which is connected to the central processing unit; There are more than two body posture sensors, which are respectively arranged on both sides of the vehicle; the body posture sensors are displacement sensors, height sensors or body inclination sensors; When the vehicle is stationary and on a flat road, the oil in the two hydraulic circuits of the hydraulic suspension system is quickly switched on and off to eliminate the oil pressure difference in the two hydraulic circuits; when the vehicle is not stationary, or / and not on a flat road, the solenoid valve is in a normally closed state, and the two circuits of the hydraulic suspension system are disconnected; The control method comprises the following steps: S1: When the vehicle starts, the vehicle speed signal is first determined. When the vehicle speed signal is zero, the vehicle body posture information and oil pressure information are determined, such as the signal of the vehicle body inclination sensor and the signal of the oil pressure sensor. If the left and right inclination angles are within the set range, and / or the oil pressure difference is within the set range, it indicates that the vehicle is parked on a horizontal road surface; S2: If the vehicle is judged to be parked on a horizontal road, the central processing unit sends a signal to the electromagnetic switch valve, which remains open for n seconds and then closes automatically. The electromagnetic switch valve is used to quickly connect and disconnect the oil in the hydraulic circuits on the left and right sides of the hydraulic suspension.

2. The control method according to claim 1, characterized in that: A damping valve structure is provided corresponding to the port of each hydraulic cylinder and between the accumulator and the corresponding hydraulic circuit. The damping valve structure is a fixed-resistance damping valve or an adjustable damping valve. If it is an adjustable damping valve, the adjustable damping valve is connected to the central processing unit.

3. The control method according to claim 1, characterized in that: The electromagnetic switch valve is an on-off electromagnetic valve, and the electromagnetic switch valve is an electromagnetic needle valve, an electromagnetic slide valve, or an electromagnetic rotary valve.

4. The control method according to claim 1, characterized in that: The hydraulic cylinder is located between the wheel and the body of the vehicle, and an elastic element is provided corresponding to the hydraulic cylinder. The hydraulic cylinder and the elastic element work in parallel to support the body.

5. The control method according to claim 1, characterized in that: The electromagnetic switch valve is a normally closed valve.

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