Vehicle height actively adjustable shock absorber system and vehicle height control strategy

Abstract

The application relates to the field of vehicle damping, and discloses a vehicle height actively adjustable damper system and a vehicle height control strategy. The damper system comprises a piston working structure, a cap shell structure and a bellows body. The piston working structure comprises a working cylinder and a large piston rod. The cap shell structure contains a low-pressure oil cavity. The top of the cap shell structure is fixed with a small piston rod, and the small piston rod is inserted into a sleeve in the large piston rod. The low-pressure oil cavity is connected with a small hollow cavity through a low-pressure flow channel. The bellows body is wrapped around the lower section of the working cylinder and forms a high-pressure oil cavity. The damper system is further provided with multiple valves. When a vehicle ECU receives a vehicle height increasing or decreasing instruction, the vehicle ECU controls the oil flow direction through the multiple valves, and changes the vehicle height by changing the oil pressure difference between the high-pressure oil cavity and the low-pressure oil cavity. The damper system and the vehicle height control strategy can actively adjust the vehicle height while damping through the multiple valves, so that the vehicle height and posture can be adjusted in real time according to the road conditions, and the comfort and driving stability of the vehicle are improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle vibration reduction, specifically to a vehicle height-adjustable vibration damper system and a vehicle height control strategy. Background Technology

[0002] Currently, to improve the smoothness of vehicle ride, most cars are equipped with shock absorbers in their suspension systems. Shock absorbers connect the vehicle frame and the axle. Most shock absorbers currently on the market are hydraulic shock absorbers. Their working principle is that when the vehicle frame and axle vibrate and experience relative motion, the piston inside the shock absorber moves up and down. The friction between the inner wall of the shock absorber and the hydraulic oil, as well as the internal friction between the hydraulic oil molecules, creates a damping force on the vibration, converting the vehicle's vibration energy into hydraulic heat energy, which is then absorbed by the shock absorber and dissipated into the atmosphere.

[0003] In the earliest automotive suspension systems, the height and performance of the shock absorbers were not adjustable. Its main drawback was that the damping force provided by the shock absorbers was only ideal for a specific operating condition; it failed to achieve the desired damping effect for conditions far removed from the specified operating conditions.

[0004] However, under different driving conditions, the vehicle height may be too high or too low, which can cause safety issues. For example, if the vehicle height is too high, it may cause the vehicle to tilt and roll over. If the vehicle height is too low, the suspension travel may be too short, resulting in poor passability. If ground obstacles hit the vehicle body, it may cause damage or breakdown. Summary of the Invention

[0005] This application provides a vehicle height-adjustable shock absorber system and a vehicle height control strategy, which can actively adjust the vehicle height while damping through multiple valves, so that the vehicle height and attitude can be adjusted in real time according to road conditions, thereby improving vehicle comfort and driving stability.

[0006] This application provides a vehicle height-actively adjustable shock absorber system, comprising:

[0007] The piston working structure includes a working cylinder and a large piston rod. The large piston rod has a large hollow cavity and a piston at its top. A sleeve containing an inner cavity is installed inside the large hollow cavity, and there is a certain backflow gap between the sleeve and the inner wall of the large piston rod.

[0008] A cap housing structure covering the upper section of the working cylinder contains a low-pressure oil chamber; a small piston rod with a small hollow cavity is fixedly installed at the top center of the cap housing structure, the lower end of the small piston rod passes through the piston and can be slidably inserted into the sleeve inside the large piston rod; the low-pressure oil chamber is connected to the small hollow cavity of the small piston rod through a low-pressure flow channel;

[0009] The bellows body, fixed to the bottom surface of the cap housing structure, is sealed and wrapped around the lower section of the working cylinder, forming a high-pressure oil chamber;

[0010] The shock absorber system is also equipped with multiple valves. When the vehicle ECU receives a command to raise or lower the vehicle height, the vehicle ECU controls the flow of oil through multiple valves and changes the vehicle height by changing the oil pressure difference between the high-pressure oil chamber and the low-pressure oil chamber.

[0011] Based on the above technical solution, the plurality of valves include:

[0012] The bypass solenoid valve, when open, connects the small hollow chamber and the working cylinder;

[0013] A one-way pressure relief valve, when opened, allows oil to flow from the working cylinder to the low-pressure oil chamber;

[0014] A one-way inlet valve that allows oil to flow from the small hollow cavity to the inner cavity of the pipe is fixed to the bottom end of the small piston rod;

[0015] A flow valve used to connect the high-pressure oil chamber and the working cylinder;

[0016] A one-way output valve located at the bottom of the casing allows oil to flow from the inner cavity of the casing to the lower rod cavity;

[0017] The one-way input valve, flow valve, and one-way output valve are normally open. When the vehicle ECU receives a vehicle height increase command, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to close. When the vehicle ECU receives a vehicle height decrease command, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to open. When the vehicle ECU receives a vehicle height maintenance command, the vehicle ECU controls the bypass solenoid valve to open and the one-way pressure relief valve to close.

[0018] Based on the above technical solution, when the vehicle ECU receives a command to raise the vehicle height, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to close.

[0019] During the stretching cycle, the small piston rod moves upward relative to the large piston rod, increasing the space of the inner cavity of the tube and decreasing the internal pressure; the oil in the low-pressure oil chamber is drawn into the small hollow cavity through the low-pressure flow channel and flows into the inner cavity of the tube through the one-way input valve;

[0020] During the compression cycle, the small piston rod moves downward relative to the large piston rod, reducing the space of the cavity inside the tube and increasing the internal pressure; the oil in the sleeve flows to the lower rod chamber through the one-way output valve; the oil in the lower rod chamber returns to the working cylinder through the return gap, and then flows to the high-pressure oil chamber through the flow valve, causing the oil pressure in the high-pressure oil chamber to rise;

[0021] The oil pressure in the high-pressure oil chamber continuously rises while the oil pressure in the low-pressure oil chamber continuously decreases, and the high-pressure oil chamber pushes the cap housing structure to rise along the working cylinder.

[0022] Based on the above technical solution, when the vehicle ECU receives the command to maintain vehicle height, the vehicle ECU controls the bypass solenoid valve to open and the one-way pressure relief valve to close; the working cylinder is directly connected to the small hollow cavity;

[0023] During the stretching cycle, the small piston rod moves upward relative to the large piston rod, and the space of the tube cavity increases. Since the oil pressure in the working cylinder is greater than that in the low-pressure oil chamber, the oil in the working cylinder is drawn into the small hollow cavity and enters the tube cavity through the one-way input valve.

[0024] During the compression cycle, the oil is forced from the inner cavity of the pipe into the lower rod cavity through the one-way output valve, and then returns to the working cylinder through the reflux gap;

[0025] After circulating from the working cylinder, the oil returns to the working cylinder. The oil pressure inside the high-pressure oil chamber and the low-pressure oil chamber remains unchanged, and there is no relative movement between the cap housing structure and the working cylinder.

[0026] Based on the above technical solution, when the vehicle ECU receives a command to lower the vehicle height, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to open; the low-pressure oil chamber, the working cylinder, and the high-pressure oil chamber are connected.

[0027] During the compression cycle, as the large piston rod and piston move upward relative to the working cylinder, they occupy an increasingly larger volume in the working cylinder, increasing the oil pressure in the working cylinder. The oil in the working cylinder flows into the low-pressure oil chamber through the one-way pressure relief valve, and the oil in the high-pressure oil chamber is replenished into the working cylinder through the flow valve.

[0028] During the stretching cycle, the small piston rod moves upward relative to the large piston rod, and the space of the inner cavity of the tube increases. Since the oil pressure in the working cylinder is greater than that in the low-pressure oil chamber, the oil in the working cylinder flows into the small hollow cavity through the bypass solenoid valve, and then passes through the one-way input valve, the inner cavity of the tube, the one-way output valve, the lower rod chamber and the return gap in sequence, and then returns to the working cylinder.

[0029] The oil pressure in the high-pressure oil chamber decreases while the oil pressure in the low-pressure oil chamber increases, and the cap housing structure slides downward along the working cylinder.

[0030] This application also discloses a vehicle height control strategy based on the above-mentioned shock absorber system, wherein the shock absorber system includes a wheel center displacement sensor disposed on the wheel assembly, a roll angle sensor disposed on the body sheet metal, a steering angle sensor disposed on the steering wheel mechanism, and two pressure sensors disposed on the low-pressure oil chamber and the high-pressure oil chamber respectively.

[0031] The vehicle height control strategy includes a manual vehicle height mode and an automatic vehicle height mode;

[0032] In manual height mode, the direct target height is input to the vehicle ECU. The vehicle ECU controls the flow of oil through multiple valves, changes the oil pressure difference between the high-pressure oil chamber and the low-pressure oil chamber, so that the cap housing structure rises or falls relative to the working cylinder to the direct target height and is maintained at the direct target height.

[0033] In automatic vehicle height mode, the vehicle ECU selects a safe target height based on the signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor. The vehicle ECU controls multiple valves to change the direction of oil flow based on the safe target height, so that the cap housing structure rises or falls relative to the working cylinder to the safe target height and is maintained at the safe target height.

[0034] Based on the above technical solution, the plurality of valves include:

[0035] The bypass solenoid valve, when open, connects the small hollow chamber and the working cylinder;

[0036] A one-way pressure relief valve, when opened, allows oil to flow from the working cylinder to the low-pressure oil chamber;

[0037] A one-way inlet valve that allows oil to flow from the small hollow cavity to the inner cavity of the pipe is fixed to the bottom end of the small piston rod;

[0038] A flow valve used to connect the high-pressure oil chamber and the working cylinder;

[0039] A one-way output valve located at the bottom of the casing allows oil to flow from the inner cavity of the casing to the lower rod cavity;

[0040] The one-way input valve, flow valve, and one-way output valve are normally open.

[0041] When the vehicle ECU receives the direct target height or the safety target height, if the vehicle height needs to be increased, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to be closed; if the vehicle height needs to be decreased, the vehicle ECU controls both the bypass solenoid valve and the one-way pressure relief valve to be opened; if the vehicle height needs to remain unchanged, the vehicle ECU controls the bypass solenoid valve to be opened and the one-way pressure relief valve to be closed.

[0042] Based on the above technical solution, the vehicle ECU selects a safe target height according to the signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor, including:

[0043] calculate,

[0044]

[0045]

[0046] Where K represents the vertical movement range of the vehicle, F represents the steering and roll degree of the vehicle; A and B are coefficients determined through design and testing; s is the measurement data of the wheel center displacement sensor, θ is the measurement data of the roll angle sensor, and α is the measurement data of the steering angle sensor.

[0047] The vehicle ECU compares K and F with their respective thresholds and selects a safe target height based on the comparison results.

[0048] Based on the above technical solution, an upper threshold M and a lower threshold N for the vertical jump amplitude of the vehicle are set for K, and a threshold P for the vehicle tilting and turning tendency is set for F.

[0049] The vehicle ECU compares K and F with their respective thresholds, and selects a safe target height based on the comparison results, including:

[0050] When K > M and F > P, the vehicle ECU selects the safe target height H4;

[0051] When K > M and F < P, the vehicle ECU selects the safe target height H5;

[0052] When M > K > N and F > P, the vehicle ECU selects the safe target height H3;

[0053] When M > K > N and K < P, the vehicle ECU selects the safe target height H4;

[0054] When N > K and F > P, the vehicle ECU selects the safe target height H1;

[0055] When N > K and F < P, the vehicle ECU selects the safe target height H2.

[0056] Based on the above technical solution, when the vehicle ECU receives the direct target height or selects the safe target height and the vehicle height needs to be increased, the vehicle ECU controls the bypass solenoid valve and the one-way pressure relief valve to close; the oil pressure in the high-pressure oil chamber continuously rises while the oil pressure in the low-pressure oil chamber continuously decreases, and the high-pressure oil chamber pushes the cap housing structure to rise along the working cylinder;

[0057] When the vehicle height needs to remain constant, the on-board ECU controls the bypass solenoid valve to open and the one-way pressure relief valve to close; the oil pressure inside the high-pressure oil chamber and the low-pressure oil chamber remains constant, and the cap housing structure and the working cylinder do not move relative to each other.

[0058] When the vehicle height needs to be lowered, the on-board ECU controls both the bypass solenoid valve and the one-way pressure relief valve to open; the oil pressure in the high-pressure oil chamber decreases and the oil pressure in the low-pressure oil chamber increases, and the cap housing structure slides downward along the working cylinder.

[0059] The beneficial effects of the technical solutions provided in this application include at least the following:

[0060] 1. The shock absorber system of this application adjusts the shock absorber height and vehicle height in real time by controlling the opening and closing of multiple valves, thereby improving vehicle comfort and driving stability. The shock absorber system of this application is ingeniously designed, using five valves to control the flow of hydraulic fluid, allowing the shock absorber to extend, remain constant, or shorten. While damping vibrations, it actively changes the vehicle height, enabling the vehicle's posture to be adjusted in real time according to road conditions, thus improving vehicle comfort and driving stability.

[0061] The shock absorber system of this application, after the vehicle ECU receives the vehicle height control command, controls the valve to switch states and change the direction of oil flow, so as to control the cap housing structure to slide upward, remain stationary, or slide downward relative to the working cylinder, thereby achieving the purpose of active vehicle height control and greatly improving driving safety and comfort.

[0062] 2. The vehicle height control strategy of this application has two vehicle height control modes: manual mode and automatic mode. It automatically adjusts the vehicle height based on a direct target height or a safe target height, greatly improving driving safety and comfort. Users can choose between automatic or manual adjustment mode, significantly enhancing convenience and providing users with more diverse options. Ultimately, this improves user experience and satisfaction.

[0063] 3. The shock absorber system of this application features an automatic vehicle height mode. The onboard ECU uses K and F to reflect actual road conditions and compares them with M, N, and P to classify six scenarios, selecting a safe target height to achieve automatic vehicle height adjustment. After selecting the safe target height, the system raises or lowers the vehicle as needed, controlling five valves to direct the flow of hydraulic fluid, adjusting the height of the shock absorber, and thus changing the vehicle height to actively adjust the vehicle height according to actual road conditions. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This is a schematic diagram of the structure of the vibration damper system provided in the embodiments of this application;

[0066] Figure 2 for Figure 1 Enlarged view of A in the middle;

[0067] Figure 3 A flowchart illustrating the vehicle height control strategy provided in this application embodiment;

[0068] Figure 4 A flowchart illustrating the automatic vehicle height mode provided in this application embodiment;

[0069] In the diagram: 100, cap housing structure; 1, low-pressure oil chamber; 2, working cylinder; 3, small piston rod; 31, small hollow cavity; 4, low-pressure flow channel; 5, bypass solenoid valve; 6, one-way pressure relief valve; 7, piston; 8, working cylinder wall; 9, high-pressure oil chamber; 10, bellows body; 11, one-way input valve; 12, large piston rod; 121, inner cavity of the pipe; 122, lower rod cavity; 13, flow valve; 14, one-way output valve; 20, sleeve; 21, return gap. Detailed Implementation

[0070] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0071] This application provides a vehicle height-adjustable shock absorber system and vehicle height control strategy. Through the cooperation of multiple valves, the vehicle height can be actively adjusted while damping, so that the vehicle height and attitude can be adjusted in real time according to road conditions, thereby improving vehicle comfort and driving stability.

[0072] like Figure 1 and Figure 2 As shown, this application discloses a vehicle height-adjustable shock absorber system, which includes a piston working structure, a cap housing structure 100, and a bellows body 10.

[0073] The piston working structure includes a working cylinder 2 and a large piston rod 12. The large piston rod 12 has a large hollow cavity, and a piston 7 is installed at the top of the large piston rod 12. A sleeve 20 is installed inside the large hollow cavity. The sleeve 20 contains an inner cavity 121. There is a certain backflow gap 21 between the sleeve 20 and the inner wall of the large piston rod 12 (see...). Figure 2 Specifically, the sleeve 20 is fixed to the inner wall of the large piston rod 12 by two or more small claw structures on its outer wall. The small claw structures meet the fixing requirements but do not hinder the flow of oil. The return gap 21 allows the oil in the lower rod cavity 122 to flow to the working cylinder 2.

[0074] The cap housing structure 100 covers the upper section of the working cylinder 2 and can slide up and down relative to the working cylinder 2. The cap housing structure 100 contains a low-pressure oil chamber 1, which is annular. A small piston rod 3 is fixedly installed at the center of the top of the cap housing structure 100, extending downwards and containing a small hollow cavity 31. The small piston rod 3 passes through the piston 7 and can be slidably inserted into the sleeve 20 inside the large piston rod 12. Furthermore, the low-pressure oil chamber 1 is connected to the small hollow cavity 31 of the small piston rod 3 via a low-pressure flow channel 4. Specifically, one end of the low-pressure flow channel 4 extends to the bottom of the low-pressure oil chamber 1, and the other end passes through the top of the cap housing structure 100 and connects to the small hollow cavity 31.

[0075] Specifically, the large piston rod 12, the small piston rod 3, the working cylinder 2, and the piston 7 are all arranged coaxially and vertically.

[0076] The top edge of the bellows body 10 is fixed to the bottom surface of the cap housing structure 100, and the bellows body 10 is sealed and wrapped around the lower section of the working cylinder 2 to form a high-pressure oil chamber 9. Specifically, the bottom edge of the bellows body 10 is fixed to the bottom surface of the working cylinder 2.

[0077] The shock absorber system is also equipped with multiple valves located in the piston working structure and the cap housing structure 100. These valves work together to influence the flow direction of the hydraulic fluid. When the vehicle ECU receives a command to raise or lower the vehicle height, it controls the flow direction of the hydraulic fluid through these valves, changing the vehicle height by altering the pressure difference between the high-pressure oil chamber 9 and the low-pressure oil chamber 1.

[0078] Specifically, the amount of oil inside the shock absorber system is constant. Multiple valves control the oil flow. If the oil volume in the high-pressure oil chamber 9 increases while the oil volume in the low-pressure oil chamber 1 decreases, the high-pressure oil chamber 9 will push up the cap housing structure 100, meaning the cap housing structure 100 will slide upwards relative to the upper section of the working cylinder 2. Conversely, if the oil volume in the high-pressure oil chamber 9 decreases while the oil volume in the low-pressure oil chamber 1 increases, the cap housing structure 100 will fall back down, meaning the cap housing structure 100 will slide downwards relative to the upper section of the working cylinder 2.

[0079] Specifically, during the process of changing the vehicle height, piston 7 moves in working cylinder 2 to provide damping force to the system.

[0080] The shock absorber system of this application adjusts the shock absorber height and vehicle height in real time by controlling the opening and closing of multiple valves, thereby improving the vehicle's comfort and driving stability.

[0081] Furthermore, the multiple valves include a bypass solenoid valve 5, a one-way pressure relief valve 6, a one-way input valve 11, a flow valve 13, and a one-way output valve 14. Specifically, the one-way input valve 11, the flow valve 13, and the one-way output valve 14 are normally open, while the bypass solenoid valve 5 and the one-way pressure relief valve 6 can be controlled to open and close.

[0082] A bypass solenoid valve 5 is located on the side wall of the small piston rod 3 and, when open, connects the small hollow cavity 31 of the small piston rod 3 and the working cylinder 2. A one-way pressure relief valve 6 is installed through the side wall of the cap housing structure 100 and, when open, connects the working cylinder 2 and the low-pressure oil chamber 1, allowing only oil to flow from the working cylinder 2 to the low-pressure oil chamber 1.

[0083] Specifically, to ensure the one-way pressure relief valve 6 functions correctly at all heights of the shock absorber, and at different positions of the cap housing structure 100 relative to the working cylinder 2, the one-way pressure relief valve 6 is installed through the side wall of the cap housing structure 100, while a vertical strip-shaped hole is provided in the cylinder wall 8 of the working cylinder at the corresponding position. Regardless of the relative position of the cap housing structure 100 and the working cylinder 2, the one-way pressure relief valve 6 will function normally.

[0084] One-way input valve 11 is fixed to the bottom end of small piston rod 3 and is located inside sleeve 20. One-way input valve 11 allows oil to flow from small hollow cavity 31 to inner cavity 121.

[0085] The flow valve 13 is located on the side wall of the working cylinder 2, connecting the high-pressure oil chamber 9 and the working cylinder 2.

[0086] The one-way output valve 14, located at the bottom of the casing 20, allows oil to flow from the inner cavity 121 to the lower rod cavity 122. Specifically, the space below the one-way output valve 14 of the large piston rod 12 is the lower rod cavity 122.

[0087] When the vehicle ECU receives a command to raise the vehicle height, it closes both the bypass solenoid valve 5 and the one-way pressure relief valve 6. At this time, the five valves cause the oil pressure in the high-pressure oil chamber 9 to increase and the oil pressure in the low-pressure oil chamber 1 to decrease during oil circulation, resulting in a larger pressure difference. When the vehicle ECU receives a command to lower the vehicle height, it opens both the bypass solenoid valve 5 and the one-way pressure relief valve 6. At this time, the five valves cause the oil pressure in the high-pressure oil chamber 9 to decrease and the oil pressure in the low-pressure oil chamber 1 to increase during oil circulation, resulting in a smaller pressure difference. When the vehicle ECU receives a command to maintain the vehicle height, it opens the bypass solenoid valve 5 and closes the one-way pressure relief valve 6. At this time, the five valves ensure that the oil pressure in both the high-pressure oil chamber 9 and the low-pressure oil chamber 1 remains constant during oil circulation.

[0088] The shock absorber system of this application is ingeniously designed. It controls the flow of oil through five valves, which can make the shock absorber extend, remain unchanged, or shorten. While reducing vibration, it can actively change the vehicle height, so that the vehicle height and posture can be adjusted in real time according to the road conditions, thereby improving the vehicle's comfort and driving stability.

[0089] In one embodiment, when the vehicle ECU receives a command to raise the vehicle height, the vehicle ECU controls both the bypass solenoid valve 5 and the one-way pressure relief valve 6 to close.

[0090] During the stretching cycle, the small piston rod 3 moves upward relative to the large piston rod 12, increasing the space of the inner cavity 121 and decreasing the internal pressure. The oil in the low-pressure oil chamber 1 is drawn into the small hollow cavity 31 through the low-pressure flow channel 4 and flows into the inner cavity 121 through the one-way input valve 11. At this time, the valve status will cause both the oil and oil pressure in the low-pressure oil chamber 1 to continuously decrease during the stretching cycle.

[0091] During the compression cycle, the small piston rod 3 moves downward relative to the large piston rod 12, reducing the space in the cavity 121 and increasing the internal pressure. The oil in the sleeve 20 flows to the lower rod cavity 122 through the one-way output valve 14. The oil in the lower rod cavity 122 returns to the working cylinder 2 through the return gap 21. Simultaneously, the large piston rod 12 and piston 7 occupy the volume of the working cylinder 2, causing the pressure in the working cylinder 2 to exceed that of the high-pressure oil cavity 9. The oil then flows to the high-pressure oil cavity 9 through the flow valve 13, causing the oil pressure in the high-pressure oil cavity 9 to rise. The valve status at this time causes both the oil volume and oil pressure in the high-pressure oil cavity 9 to continuously rise during the compression cycle.

[0092] The oil pressure in the high-pressure oil chamber 9 continuously increases while the oil pressure in the low-pressure oil chamber 1 continuously decreases. The high-pressure oil chamber 9 pushes the cap housing structure 100 to rise along the working cylinder 2, causing the entire shock absorber to extend.

[0093] In one embodiment, when the shock absorber height reaches the preset target height, the vehicle ECU receives a command to maintain vehicle height, and the vehicle ECU controls the bypass solenoid valve 5 to open and the one-way pressure relief valve 6 to close. The working cylinder 2 is directly connected to the small hollow cavity 31.

[0094] During the stretching cycle, the small piston rod 3 moves upward relative to the large piston rod 12, increasing the space of the inner cavity 121. Since the oil pressure in the working cylinder 2 is greater than that in the low-pressure oil chamber 1, the oil in the working cylinder 2 is preferentially drawn into the small hollow cavity 31 and enters the inner cavity 121 through the one-way input valve 11.

[0095] During the compression cycle, the oil is forced from the inner cavity 121 through the one-way output valve 14 into the lower rod cavity 122, and then returns to the working cylinder 2 through the return gap 21.

[0096] At this time, the valve state will cause the oil to circulate from the working cylinder 2 and return to the working cylinder 2 during the stretching and compression cycles. The oil pressure inside the high-pressure oil chamber 9 and the low-pressure oil chamber 1 remains unchanged. The cap housing structure 100 and the working cylinder 2 do not move relative to each other, and the entire shock absorber maintains its current height.

[0097] In one embodiment, when the vehicle ECU receives a vehicle height reduction command, the vehicle ECU controls both the bypass solenoid valve 5 and the one-way pressure relief valve 6 to open; the low-pressure oil chamber 1, the working cylinder 2, and the high-pressure oil chamber 9 are connected. The one-way pressure relief valve 6 ensures that oil can only flow into the low-pressure oil chamber 1 from the working cylinder 2 in one direction.

[0098] During the compression cycle, as the large piston rod 12 and piston 7 move upward relative to the working cylinder 2, they occupy an increasingly larger volume in the working cylinder 2, increasing the oil pressure. The oil in the working cylinder 2 flows into the low-pressure oil chamber 1 through the one-way pressure relief valve 6, while the oil in the high-pressure oil chamber 9 is replenished into the working cylinder 2 through the flow valve 13. This valve status causes the oil and oil pressure in the high-pressure oil chamber 9 to continuously decrease during the compression cycle, while the oil and oil pressure in the low-pressure oil chamber 1 continuously increase.

[0099] During the stretching cycle, the small piston rod 3 moves upward relative to the large piston rod 12, increasing the space of the cavity 121 inside the tube. Since the oil pressure in the working cylinder 2 is greater than that in the low-pressure oil chamber 1, the oil in the working cylinder 2 preferably flows into the small hollow cavity 31 through the bypass solenoid valve 5, and then sequentially passes through the one-way input valve 11, the cavity 121 inside the tube, the one-way output valve 14, the lower rod chamber 122, and the return gap 21, before returning to the working cylinder 2. The valve state at this time ensures that during the stretching cycle, the oil circulates within the working cylinder 2, and the oil level and pressure in both the high-pressure oil chamber 9 and the low-pressure oil chamber 1 remain unchanged.

[0100] In summary, the oil and oil pressure in the high-pressure oil chamber 9 continuously decrease, while the oil and oil pressure in the low-pressure oil chamber 1 continuously increase. The cap housing structure 100 slides downward along the working cylinder 2, and the entire shock absorber shortens as a whole.

[0101] The shock absorber system of this application, after the vehicle ECU receives the vehicle height control command, controls the valve to switch states and change the oil flow direction, so as to control the cap housing structure 100 to slide upward, remain stationary, and slide downward relative to the working cylinder 2, thereby achieving the purpose of active vehicle height control and greatly improving driving safety and comfort.

[0102] like Figure 3 and Figure 4As shown, this application also discloses a vehicle height control strategy based on the above-mentioned shock absorber system. The shock absorber system includes a wheel center displacement sensor installed on the wheel assembly, a roll angle sensor installed on the body sheet metal, a steering angle sensor installed on the steering wheel mechanism, and two pressure sensors respectively installed in the low-pressure oil chamber 1 and the high-pressure oil chamber 9.

[0103] Specifically, the data measured by the wheel center displacement sensor, roll angle sensor, and steering angle sensor can characterize the road surface conditions.

[0104] During the development of a new vehicle, the pressures of the low-pressure oil chamber 1 and the high-pressure oil chamber 9 in the initial state are known. When the vehicle height is maintained, the relationship between the target vehicle height and the pressure difference between the two oil chambers is calibrated in advance.

[0105] The vehicle height control strategy includes a manual vehicle height mode and an automatic vehicle height mode;

[0106] In manual height mode, the direct target height command is input to the vehicle ECU. The ECU controls the flow of hydraulic fluid through multiple valves, changing the pressure difference between the high-pressure oil chamber 9 and the low-pressure oil chamber 1. This causes the cap housing structure 100 to rise or fall relative to the working cylinder 2 to the direct target height and maintain that height. Specifically, after rising or falling to the direct target height, the states of multiple valves are switched again, and then the height is maintained at the direct target height. The direct target height command can be input to the vehicle ECU from the operator display screen in the driver's cab.

[0107] In automatic vehicle height mode, a safe target height is selected based on signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor. The onboard ECU controls multiple valves to change the oil flow direction based on this target height, thereby altering the oil pressure difference between the high-pressure oil chamber 9 and the low-pressure oil chamber 1. This causes the cap housing structure 100 to rise or fall relative to the working cylinder 2 to the safe target height and maintain that height. Similarly, after rising or falling to the direct target height, the states of multiple valves are switched again, and then the height is maintained at the direct target height.

[0108] The vehicle height control strategy of this application features two control modes: manual and automatic. It automatically adjusts the vehicle height based on a direct target height or a safe target height, significantly improving driving safety and comfort. Users can choose between automatic or manual adjustment, greatly enhancing convenience and providing more diverse options. Ultimately, this improves user experience and satisfaction.

[0109] Regarding the vehicle height control strategy, in one embodiment...

[0110] Furthermore, the multiple valves include a bypass solenoid valve 5, a one-way pressure relief valve 6, a one-way input valve 11, a flow valve 13, and a one-way output valve 14. Specifically, the one-way input valve 11, the flow valve 13, and the one-way output valve 14 are normally open, while the bypass solenoid valve 5 and the one-way pressure relief valve 6 can be controlled to open and close.

[0111] A bypass solenoid valve 5 is located on the side wall of the small piston rod 3 and, when open, connects the small hollow cavity 31 of the small piston rod 3 and the working cylinder 2. A one-way pressure relief valve 6 is installed through the side wall of the cap housing structure 100 and, when open, connects the working cylinder 2 and the low-pressure oil chamber 1, allowing only oil to flow from the working cylinder 2 to the low-pressure oil chamber 1.

[0112] Specifically, to ensure the one-way pressure relief valve 6 functions correctly at all heights of the shock absorber, and at different positions of the cap housing structure 100 relative to the working cylinder 2, the one-way pressure relief valve 6 is installed through the side wall of the cap housing structure 100, while a vertical strip-shaped hole is provided in the cylinder wall 8 of the working cylinder at the corresponding position. Regardless of the relative position of the cap housing structure 100 and the working cylinder 2, the one-way pressure relief valve 6 will function normally.

[0113] One-way input valve 11 is fixed to the bottom end of small piston rod 3 and is located inside sleeve 20. One-way input valve 11 allows oil to flow from small hollow cavity 31 to inner cavity 121.

[0114] The flow valve 13 is located on the side wall of the working cylinder 2, connecting the high-pressure oil chamber 9 and the working cylinder 2.

[0115] The one-way output valve 14, located at the bottom of the casing 20, allows oil to flow from the inner cavity 121 to the lower rod cavity 122. Specifically, the space below the one-way output valve 14 of the large piston rod 12 is the lower rod cavity 122.

[0116] When the vehicle ECU receives a direct target height or a safety target height, and the vehicle height needs to be increased, the vehicle ECU controls the bypass solenoid valve 5 and the one-way pressure relief valve 6 to both close. At this time, during the oil circulation process, the oil pressure in the high-pressure oil chamber 9 increases, and the oil pressure in the low-pressure oil chamber 1 decreases, resulting in a larger oil pressure difference. When the vehicle ECU receives a direct target height or a safety target height, and the vehicle height needs to be decreased, the vehicle ECU controls the bypass solenoid valve 5 and the one-way pressure relief valve 6 to both open. At this time, during the oil circulation process, the oil pressure in the high-pressure oil chamber 9 decreases, and the oil pressure in the low-pressure oil chamber 1 increases, resulting in a smaller oil pressure difference. When the vehicle ECU receives a direct target height or a safety target height, and the vehicle height needs to remain unchanged, the vehicle ECU controls the bypass solenoid valve 5 to open and the one-way pressure relief valve 6 to close. At this time, during the oil circulation process, the oil pressure in both the high-pressure oil chamber 9 and the low-pressure oil chamber 1 remains constant.

[0117] The shock absorber system of this application is ingeniously designed. It controls the flow of oil through five valves, which can make the shock absorber extend, remain unchanged, or shorten. While reducing vibration, it can actively change the vehicle height, so that the vehicle height and posture can be adjusted in real time according to the road conditions, thereby improving the vehicle's comfort and driving stability.

[0118] Regarding the shock absorber system, in one embodiment, the on-board ECU selects a safe target height based on signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor, including:

[0119] calculate,

[0120]

[0121]

[0122] Where K represents the vertical movement range of the vehicle, F represents the steering range and roll degree of the vehicle; A and B are coefficients determined through design and testing. s is the measurement data from the wheel center displacement sensor, θ is the measurement data from the roll angle sensor, and α is the measurement data from the steering angle sensor.

[0123] K and F are compared with their respective thresholds, and the vehicle ECU selects the safe target height based on the comparison results.

[0124] Specifically, s, θ, and α represent the road conditions on which the vehicle travels.

[0125] Furthermore, for K, an upper threshold M and a lower threshold N for the vertical jump amplitude of the vehicle are set, and for F, a threshold P for the vehicle's side tilt and turning tendency is set.

[0126] The vehicle ECU compares K and F with their respective thresholds, and selects a safe target height based on the comparison results, including:

[0127] When K > M and F > P, it means that the vehicle's vertical jump is large and the vehicle's side tilt and turning is large. At this time, both indicators are very dangerous, and the chassis height needs to be lowered quickly to prevent rollover. The vehicle ECU selects the safe target height H4.

[0128] When K > M and F < P, it means that the vehicle's vertical jump is large, but the vehicle's side tilt and turning are stable, and the vehicle ECU selects the safe target height H5; specifically, H4 < H5.

[0129] When M > K > N and F > P, it means that the vehicle's vertical jump is moderate and has not reached its limit, but the vehicle's lateral tilt is large and there is a risk of tilting. The vehicle ECU selects the safe target height H3.

[0130] When M > K > N and K < P, it means that the vehicle's vertical movement is moderate and the vehicle's side tilting and turning are stable, and the vehicle's ECU selects the safe target height H4.

[0131] When N > K and F > P, it means that the vehicle's vertical jump is very small, the vehicle's lateral tilt is large, and the vehicle ECU selects the safe target height H1.

[0132] When N > K and F < P, it means that the vehicle's vertical movement is very small, the vehicle is stable when tilting and turning, and the on-board ECU selects the safe target height H2.

[0133] The shock absorber system of this application features an automatic vehicle height mode. The onboard ECU uses K and F to reflect actual road conditions and compares them with M, N, and P to classify six scenarios, selecting a safe target height to achieve automatic vehicle height adjustment. After selecting the safe target height, the system raises or lowers the vehicle as needed by controlling five valves to direct the flow of hydraulic fluid, adjusting the height of the shock absorber and thus changing the vehicle height to actively adjust the vehicle height according to actual road conditions.

[0134] Regarding the vehicle height control strategy, in one embodiment, when the vehicle ECU receives the direct target height or selects a safe target height H1, H2, H3, H4 or H5, and the vehicle height needs to be increased, the vehicle ECU controls the bypass solenoid valve 5 and the one-way pressure relief valve 6 to close; the oil pressure in the high-pressure oil chamber 9 continuously rises while the oil pressure in the low-pressure oil chamber 1 continuously decreases, and the high-pressure oil chamber 9 pushes the cap housing structure 100 to rise along the working cylinder 2.

[0135] When the vehicle height needs to remain unchanged, the vehicle ECU controls the bypass solenoid valve 5 to open and the one-way pressure relief valve 6 to close; the oil pressure inside the high-pressure oil chamber 9 and the low-pressure oil chamber 1 remains unchanged, and the cap housing structure 100 and the working cylinder 2 do not move relative to each other.

[0136] When the vehicle height needs to be lowered, the vehicle ECU controls the bypass solenoid valve 5 and the one-way pressure relief valve 6 to open; the oil pressure in the high-pressure oil chamber 9 decreases and the oil pressure in the low-pressure oil chamber 1 increases, and the cap housing structure 100 slides downward along the working cylinder 2.

[0137] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0138] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0139] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A vehicle height-actively adjustable shock absorber system, characterized in that, Include: The piston working structure includes a working cylinder (2) and a large piston rod (12). The large piston rod (12) has a large hollow cavity and a piston (7) is provided at the top. The large hollow cavity is provided with a sleeve (20) containing a tube cavity (121), and there is a certain backflow gap (21) between the sleeve (20) and the inner wall of the large piston rod (12). A cap shell structure (100) is installed on the upper part of the working cylinder (2), which contains a low-pressure oil chamber (1); a small piston rod (3) with a small hollow cavity (31) is fixedly installed at the center of the top of the cap shell structure (100), and the lower end of the small piston rod (3) passes through the piston (7) and can be slidably inserted into the sleeve (20) inside the large piston rod (12); the low-pressure oil chamber (1) is connected to the small hollow cavity (31) of the small piston rod (3) through the low-pressure flow channel (4); The bellows body (10) fixed to the bottom surface of the cap housing structure (100) is sealed and wrapped around the lower section of the working cylinder (2) to form a high-pressure oil chamber (9). The shock absorber system is also equipped with multiple valves. When the vehicle ECU receives a command to raise or lower the vehicle height, the vehicle ECU controls the flow of oil through multiple valves and changes the vehicle height by changing the oil pressure difference between the high-pressure oil chamber (9) and the low-pressure oil chamber (1). The plurality of valves includes: The bypass solenoid valve (5) is used to connect the small hollow cavity (31) and the working cylinder (2) when it is open. One-way pressure relief valve (6) allows oil to flow from working cylinder (2) to low-pressure oil chamber (1) when it is open; A one-way inlet valve (11) that allows oil to flow from the small hollow cavity (31) to the inner cavity (121) of the pipe is fixed to the bottom end of the small piston rod (3); A flow valve (13) for connecting the high-pressure oil chamber (9) and the working cylinder (2); A one-way output valve (14) located at the bottom of the casing (20) allows oil to flow from the inner cavity (121) of the pipe to the lower rod cavity (122). The one-way input valve (11), flow valve (13) and one-way output valve (14) are normally open. When the vehicle ECU receives a vehicle height increase command, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to close. When the vehicle ECU receives a vehicle height decrease command, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to open. When the vehicle ECU receives a vehicle height maintenance command, the vehicle ECU controls the bypass solenoid valve (5) to open and the one-way pressure relief valve (6) to close.

2. The vehicle height-actively adjustable shock absorber system as described in claim 1, characterized in that, When the vehicle ECU receives a command to raise the vehicle height, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to close. During the stretching cycle, the small piston rod (3) moves upward relative to the large piston rod (12), the space of the inner cavity (121) increases and the internal pressure decreases; the oil in the low-pressure oil chamber (1) is drawn into the small hollow cavity (31) through the low-pressure flow channel (4) and flows into the inner cavity (121) through the one-way input valve (11); During the compression cycle, the small piston rod (3) moves downward relative to the large piston rod (12), reducing the space of the cavity (121) and increasing the internal pressure; the oil in the sleeve (20) flows to the lower rod chamber (122) through the one-way output valve (14); the oil in the lower rod chamber (122) returns to the working cylinder (2) through the return gap (21), and then flows to the high-pressure oil chamber (9) through the flow valve (13), causing the oil pressure in the high-pressure oil chamber (9) to rise; The oil pressure in the high-pressure oil chamber (9) continuously rises while the oil pressure in the low-pressure oil chamber (1) continuously decreases. The high-pressure oil chamber (9) pushes the cap housing structure (100) to rise along the working cylinder (2).

3. The vehicle height-actively adjustable shock absorber system as described in claim 1, characterized in that, When the vehicle ECU receives the command to maintain vehicle height, the vehicle ECU controls the bypass solenoid valve (5) to open and the one-way pressure relief valve (6) to close; the working cylinder (2) is directly connected to the small hollow cavity (31); During the stretching cycle, the small piston rod (3) moves upward relative to the large piston rod (12), and the space of the tube cavity (121) increases. Since the oil pressure of the working cylinder (2) is greater than that of the low-pressure oil chamber (1), the oil in the working cylinder (2) is sucked into the small hollow cavity (31) and enters the tube cavity (121) through the one-way input valve (11). During the compression cycle, the oil is pushed from the inner cavity (121) through the one-way output valve (14) into the lower rod cavity (122), and then returns to the working cylinder (2) through the return gap (21). After the oil circulates from the working cylinder (2), it returns to the working cylinder (2). The oil pressure inside the high-pressure oil chamber (9) and the low-pressure oil chamber (1) remains unchanged, and the cap housing structure (100) and the working cylinder (2) do not move relative to each other.

4. The vehicle height-actively adjustable shock absorber system as described in claim 1, characterized in that, When the vehicle ECU receives a command to lower the vehicle height, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to open; the low-pressure oil chamber (1), the working cylinder (2) and the high-pressure oil chamber (9) are connected; During the compression cycle, when the large piston rod (12) and piston (7) move upward relative to the working cylinder (2), they occupy more and more volume in the working cylinder (2), the oil pressure in the working cylinder (2) increases, and the oil in the working cylinder (2) flows into the low-pressure oil chamber (1) through the one-way pressure relief valve (6), and the oil in the high-pressure oil chamber (9) is replenished into the working cylinder (2) through the flow valve (13). During the stretching cycle, the small piston rod (3) moves upward relative to the large piston rod (12), and the space of the tube cavity (121) increases. Since the oil pressure of the working cylinder (2) is greater than that of the low-pressure oil chamber (1), the oil in the working cylinder (2) flows into the small hollow cavity (31) through the bypass solenoid valve (5), and then passes through the one-way input valve (11), the tube cavity (121), the one-way output valve (14), the lower rod cavity (122), and the return gap (21) in sequence, and then returns to the working cylinder (2). The oil pressure in the high-pressure oil chamber (9) decreases and the oil pressure in the low-pressure oil chamber (1) increases, and the cap housing structure (100) slides downward along the working cylinder (2).

5. A vehicle height control strategy based on the shock absorber system of claim 1, characterized in that: The shock absorber system includes a wheel center displacement sensor installed on the wheel assembly, a roll angle sensor installed on the body sheet metal, a steering angle sensor installed on the steering wheel mechanism, and two pressure sensors installed in the low-pressure oil chamber (1) and the high-pressure oil chamber (9), respectively. The vehicle height control strategy includes a manual vehicle height mode and an automatic vehicle height mode; In manual mode, the direct target height command is input to the vehicle ECU. The vehicle ECU controls the flow of oil through multiple valves, changes the oil pressure difference between the high-pressure oil chamber (9) and the low-pressure oil chamber (1), so that the cap housing structure (100) rises or falls relative to the working cylinder (2) to the direct target height and is maintained at the direct target height. In automatic vehicle height mode, the vehicle ECU selects a safe target height based on the signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor; the vehicle ECU controls multiple valves to change the oil flow direction based on the safe target height, so that the cap housing structure (100) rises or falls relative to the working cylinder (2) to the safe target height and is maintained at the safe target height; The plurality of valves includes: The bypass solenoid valve (5) is used to connect the small hollow cavity (31) and the working cylinder (2) when it is open. One-way pressure relief valve (6) allows oil to flow from working cylinder (2) to low-pressure oil chamber (1) when it is open; A one-way inlet valve (11) that allows oil to flow from the small hollow cavity (31) to the inner cavity (121) of the pipe is fixed to the bottom end of the small piston rod (3); A flow valve (13) for connecting the high-pressure oil chamber (9) and the working cylinder (2); A one-way output valve (14) located at the bottom of the casing (20) allows oil to flow from the inner cavity (121) of the pipe to the lower rod cavity (122). The one-way input valve (11), flow valve (13) and one-way output valve (14) are in the normally open state; When the vehicle ECU receives the direct target height or the safety target height, if the vehicle height needs to be increased, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to be closed; if the vehicle height needs to be decreased, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to be opened; if the vehicle height needs to remain unchanged, the vehicle ECU controls the bypass solenoid valve (5) to be opened and the one-way pressure relief valve (6) to be closed.

6. The vehicle height control strategy as described in claim 5, characterized in that, The vehicle ECU selects a safe target height based on signals received from the wheel center displacement sensor, roll angle sensor, and steering angle sensor, including: calculate, ； ； Where K represents the vertical movement range of the vehicle, F represents the steering and roll degree of the vehicle; A and B are coefficients determined through design and testing; s is the measurement data of the wheel center displacement sensor, θ is the measurement data of the roll angle sensor, and α is the measurement data of the steering angle sensor. The vehicle ECU compares K and F with their respective thresholds and selects a safe target height based on the comparison results.

7. The vehicle height control strategy as described in claim 6, characterized in that, For K, set an upper threshold M and a lower threshold N for the vertical jump amplitude of the vehicle; for F, set a threshold P for the vehicle's side tilt and turning tendency. The vehicle ECU compares K and F with their respective thresholds, and selects a safe target height based on the comparison results, including: When K > M and F > P, the vehicle ECU selects the safe target height H4; When K > M and F < P, the vehicle ECU selects the safe target height H5; When M > K > N and F > P, the vehicle ECU selects the safe target height H3; When M > K > N and K < P, the vehicle ECU selects the safe target height H4; When N > K and F > P, the vehicle ECU selects the safe target height H1; When N > K and F < P, the vehicle ECU selects the safe target height H2.

8. The vehicle height control strategy as described in claim 7, characterized in that: When the vehicle ECU receives the direct target height or selects the safe target height, and the vehicle height needs to be increased, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to close. The oil pressure in the high-pressure oil chamber (9) continuously rises while the oil pressure in the low-pressure oil chamber (1) continuously decreases. The high-pressure oil chamber (9) pushes the cap housing structure (100) to rise along the working cylinder (2). When the vehicle height needs to remain unchanged, the vehicle ECU controls the bypass solenoid valve (5) to open and the one-way pressure relief valve (6) to close; the oil pressure inside the high-pressure oil chamber (9) and the low-pressure oil chamber (1) remains unchanged, and the cap housing structure (100) and the working cylinder (2) do not move relative to each other; When the vehicle height needs to be lowered, the vehicle ECU controls the bypass solenoid valve (5) and the one-way pressure relief valve (6) to open; the oil pressure in the high-pressure oil chamber (9) decreases and the oil pressure in the low-pressure oil chamber (1) increases, and the cap housing structure (100) slides downward along the working cylinder (2).

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