An air suspension system and its desiccant humidity control method
By using closed-loop control and PID algorithms, combined with humidity and pressure sensors, the humidity of the dryer can be adjusted in real time, solving the problem of inaccurate humidity control in the air suspension system, achieving energy consumption optimization and component protection, and improving the system's applicability and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG MEICHEN ADVANCED POLYMER MATERIALS TECH CO LTD
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
AI Technical Summary
In existing passenger vehicle air suspension systems, the humidity control of the desiccant cannot be precisely adjusted, leading to premature deactivation of the adsorbent or excessive moisture residue. Furthermore, it consumes a lot of energy and cannot adapt to humidity changes in different regions and seasons.
A closed-loop control method combined with a PID algorithm is adopted. The humidity of the drying tank is detected in real time by humidity and pressure sensors, the backflushing time is calculated, and the humidity of the drying tank is adjusted according to vehicle speed and ambient temperature to reduce energy consumption.
It achieves precise closed-loop control of the humidity in the drying tank, avoids adsorbent failure, reduces energy consumption, protects system components, adapts to different environmental conditions, and improves system reliability and service life.
Smart Images
Figure CN122308498A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automotive parts technology, specifically to an air suspension system and a method for controlling the humidity of its dryer canister. Background Technology
[0002] Currently, most passenger car chassis air suspension systems use an open air supply system. The air pump compresses the outside air, dries it in a dryer, and stores it in an air tank. When the vehicle is lifted, it supplies air to the air springs, and when it is lowered, it exhausts directly to the atmosphere. Excessive moisture in the system can corrode metal parts, and in low-temperature environments, it can easily cause the distribution valve body to freeze, leading to charging and exhaust failures or even valve body burnout.
[0003] Existing humidity control methods for drying tanks use open-loop fixed-cycle regeneration, which cannot adjust the backflushing time according to the actual humidity, easily leading to premature adsorbent failure or excessive moisture residue. Some solutions estimate the moisture content by the total intake air volume, without considering regional and seasonal humidity differences, resulting in low control accuracy and frequent exhaust increasing compressed air consumption and system energy consumption.
[0004] Therefore, there is an urgent need for an air suspension system that can precisely regulate the humidity of the drying tank, adapt to environmental changes, and reduce energy consumption, as well as a method for controlling the humidity of the drying tank. Summary of the Invention
[0005] To address the aforementioned issues, this invention aims to provide an air suspension system and a method for controlling the humidity of its dryer canister, thereby achieving precise closed-loop control of the dryer canister humidity, improving system reliability and service life, and reducing energy consumption.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: an air suspension system, comprising an air filter, a muffler, an air pump and a gas distribution valve connected in sequence, wherein the gas distribution valve is connected to the left front air spring, the right front air spring, the left rear air spring, the right rear air spring and an air tank respectively. The air pump includes a compressor and a dryer. The muffler is connected to the main gas distribution valve via the compressor, dryer, and dryer check valve. The pneumatic exhaust valve has two inlet ends. One of the inlet ends is connected to the main gas distribution valve via an electronically controlled exhaust valve. The other inlet end is connected to the pipeline between the compressor and the dryer. The dryer is connected to a humidity sensor. The single outlet end of the pneumatic exhaust valve is connected to the pipeline between the muffler and the compressor. The gas distribution valve includes multiple air spring solenoid valves and a gas tank solenoid valve. The main circuit of the gas distribution valve is connected to the left front air spring, right front air spring, left rear air spring and right rear air spring through each corresponding air spring solenoid valve. The main circuit of the gas distribution valve is connected to the gas tank through the gas tank solenoid valve.
[0007] Furthermore, the compressor is driven by a motor, and the motor is equipped with a temperature sensor.
[0008] Furthermore, the outlet of the electronically controlled exhaust valve is connected in one direction to the drying tank and the drying check valve via a backflush check valve.
[0009] Furthermore, the gas storage tank is also connected to a pressure sensor.
[0010] The present invention also relates to a method for controlling the humidity of the desiccant of the above-mentioned air suspension system, comprising the following steps: The air pump draws in outside air, pressurizes it, and dries it through a drying tank. The dried gas is then sent to a storage tank through a gas distribution valve. When the humidity in the drying tank becomes too high, the storage tank vents in reverse, carrying away the moisture from the drying tank and expelling it to the outside.
[0011] Furthermore, the specific steps include: Step 1: The humidity sensor detects the humidity of the drying can as A; Step 2: The pressure sensor detects the pressure P in the gas storage tank; Step 3: Set the humidity target for the drying tank to SP=30%RH; Step 4: Compare the difference between the target humidity and the current humidity. The drying process follows an exponential decay law, and logarithmic error is used to control the backflushing time. Logarithmic error When A≤SP, the humidity requirement is met, so let e=0, backflushing time t=0, and do not start the backflushing process; When A > SP, e is a positive number, which is substituted into the PID formula to calculate the backflush time; Step 5: Calculate the backflush time t using the PID control method, as shown in the following formula: ; Where K p For proportional gain, K i For integral gain, K d Let ∫edt be the differential gain, ∫edt be the cumulative integral of the error e over time, and de / dt be the rate of change of the derivative of the error e; K p The formula is related to the drying tank volume V1 and the average backflushing volumetric flow rate Q, and is as follows: ; V1 is the volume of the drying tank, C d , where A1 is the flow coefficient, ranging from 0.6 to 0.8, A1 is the cross-sectional area of the backflush pipe, in m², and P is the initial absolute pressure of the gas storage tank. atm The pressure is standard atmosphere, and ρ is the air density. K i =K p ×T i Ti The integral time constant; K d =K p ×T d T d The differential time constant; The integration time constant T i The value is taken as the system's dominant time constant τ, which is obtained by allowing the humidity inside the drying tank to naturally decrease from 80%RH to 30%RH, and recording the half-life t of the decrease process. 1 / 2 ,but Then let T i =τ,T d =0.2τ. If no experimental conditions are available, T can be preset. i =5s, T d =1s as the initial value, and then fine-tune it according to the on-site debugging. Step 6: The electronically controlled exhaust valve opens, and the compressed gas in the storage tank flows to the outside through the dryer, silencer, and air filter. It closes after time t.
[0012] Furthermore, during the process of releasing gas from the storage tank, the pressure sensor detects the pressure P of the storage tank. If P is less than 1.0 MPa, the gas release is stopped.
[0013] Furthermore, when the vehicle is stationary, the air tank is not replenished. When the vehicle is moving, wind noise and road noise will mask the sound of the air pump working. At this time, the air tank is replenished, based on the vehicle speed. When the vehicle speed is >30 km / h and the air tank pressure is less than 1.0 MPa, the air pump is started and works to fill the air tank. When the air tank pressure reaches 1.6 MPa, the air supply is stopped.
[0014] Furthermore, when the humidity A of the drying tank is greater than 80%RH, the system performs backflushing to dry the drying tank.
[0015] Furthermore, the backflushing control system also receives the ambient temperature signal from the vehicle via the CAN bus. When the ambient temperature is below zero degrees Celsius and the humidity A of the dryer can is greater than 70%RH, the system will perform backflushing.
[0016] With the above settings, the beneficial effects of the present invention are: 1. Closed-loop precise control: Based on real-time humidity, the backflushing time is calculated using logarithmic error + PID algorithm to adapt to different ambient humidity and avoid adsorbent failure and moisture residue; 2. Low-temperature protection: Low-temperature environments reduce the backflushing humidity threshold, preventing the valve block from freezing and being damaged; 3. Energy consumption optimization: Backflushing is triggered based on humidity threshold, and air replenishment is controlled by vehicle speed to reduce ineffective work and reduce compressed air loss; 4. Component protection: The air pump is equipped with temperature and operating time protection to extend the service life of the air pump and the dryer. 5. Enhanced applicability: Suitable for low-temperature and high-humidity areas, ensuring stable operation of the air suspension system. Attached Figure Description
[0017] The invention will now be further described with reference to the accompanying drawings.
[0018] Figure 1 Schematic diagram of the overall structure of the air suspension system in Embodiment 1 of the present invention; Figure 2 Schematic diagram of the air intake process of the air suspension system in Embodiment 1 of the present invention; Figure 3 Schematic diagram of the exhaust process of the air suspension system in Embodiment 1 of the present invention; Figure 4 Schematic diagram of the backflushing process of the drying tank in Embodiment 1 of the present invention; Figure 5 Flowchart of the humidity control method for the drying tank in Embodiment 2 of the present invention. Detailed Implementation Example 1
[0019] like Figure 1-4 As shown, an air suspension system includes an air filter 10, a muffler 20, an air pump 30, and a gas distribution valve 40 connected in sequence. The gas distribution valve 40 is connected to the left front air spring 50, the right front air spring 60, the left rear air spring 70, the right rear air spring 80, and an air tank 90. The air pump 30 includes a compressor 302 and a dryer 304. The muffler 20 is connected to the air supply via the compressor 302, the dryer 304, and the dryer check valve 306. The main circuit of the gas distribution valve 40 is connected, and the pneumatic exhaust valve 309 has two air inlets. One of the two air inlets of the pneumatic exhaust valve 309 is connected to the main circuit of the gas distribution valve 40 through the electronically controlled exhaust valve 308. The other air inlet of the pneumatic exhaust valve 309 is connected to the pipeline between the compressor 302 and the dryer 304. The dryer 304 is connected to the humidity sensor 305. The single air outlet of the pneumatic exhaust valve 309 is connected to the pipeline between the silencer 20 and the compressor 302. Specifically: The gas distribution valve 40 includes multiple (specifically four) air spring solenoid valves 401 and a gas storage tank solenoid valve 402. The main circuit of the gas distribution valve 40 is connected to the left front air spring 50, right front air spring 60, left rear air spring 70 and right rear air spring 80 through each corresponding air spring solenoid valve 401. The main circuit of the gas distribution valve 40 is connected to the gas storage tank 90 through the gas storage tank solenoid valve 402. The compressor 302 is driven by the motor 301, and the motor 301 is equipped with a temperature sensor 303. The outlet of the electrically controlled exhaust valve 308 is connected in one direction through the pipeline between the backflush check valve 307 and the dryer 304 and the dryer check valve 306. The gas storage tank 90 is also connected to a pressure sensor 403.
[0020] 1. Intake process ( Figure 2 ) Outside air is filtered for impurities by air filter 10 and reduced for noise by muffler 20 before entering compressor 302 for pressurization. After being dried by moisture adsorption in dryer 304, the pressurized gas passes through dryer check valve 306 and gas distribution valve 40, and then enters the corresponding air spring through air spring solenoid valve 401, and finally enters air storage tank 90 through air storage tank solenoid valve 402.
[0021] 2. Exhaust process ( Figure 3 ) The high-pressure gas inside the air spring is discharged to the outside through the gas distribution valve 40, the electronically controlled exhaust valve 308, the backflush check valve 307, the dryer 304, the pneumatic exhaust valve 309, the muffler 20, and the air filter 10, thereby reducing the vehicle height.
[0022] 3. Backflush process ( Figure 4 ) High-pressure gas in the gas storage tank 90 flows through the gas distribution valve 40, the electrically controlled exhaust valve 308, and the backflush check valve 307 through the drying tank 304, carrying out the water vapor in the drying tank. The gas is then discharged to the outside through the pneumatic exhaust valve 309, the silencer 20, and the air filter 10, thus completing the regeneration of the drying tank. Example 2
[0023] like Figure 5 As shown, the humidity control method for the dryer tank of the air suspension system in Example 1 includes the following steps: Air pump 30 draws in outside air, pressurizes it, and dries it through dryer 304. The dried gas is then sent to storage tank 90 through gas distribution valve 40. When the humidity in dryer 304 is too high, storage tank 90 exhausts air in reverse, carrying away the moisture in dryer 304 and discharging it to the outside.
[0024] Specifically, the following steps are included: Step 1: Humidity sensor 305 detects the humidity of drying tank 304 as A; Step 2: Pressure sensor 403 detects the pressure P in gas storage tank 90; Step 3: Set the humidity target SP of the drying tank 304 to 30%RH; Step 4: Compare the difference between the target humidity and the current humidity. The drying process follows an exponential decay law, and logarithmic error is used to control the backflushing time. Logarithmic error ; When A≤SP, the humidity requirement is met, so let e=0, backflushing time t=0, and do not start the backflushing process; When A > SP, e is a positive number, which is substituted into the PID formula to calculate the backflush time; Step 5: Calculate the backflush time t using the PID control method, as shown in the following formula: ; Where K p For proportional gain, K i For integral gain, K d Let ∫edt be the differential gain, ∫edt be the cumulative integral of the error e over time, and de / dt be the rate of change of the derivative of the error e; Kp is related to the drying tank volume V1 and the average backflushing volumetric flow rate Q, and the calculation formula is as follows: ; V1 is the volume of the drying tank, C d , where A1 is the flow coefficient, ranging from 0.6 to 0.8, A1 is the cross-sectional area of the backflush pipe, in m², and P is the initial absolute pressure of the gas storage tank. atm The pressure is standard atmosphere, and ρ is the air density. K i =K p ×T i Where Ti is the integration time constant; K d =K p ×T d T d The differential time constant; The integration time constant T i The value is taken as the system's dominant time constant τ, which is obtained by allowing the humidity inside the drying tank to naturally decrease from 80%RH to 30%RH, and recording the half-life t of the decrease process. 1 / 2 ,but Then let T i =τ,T d =0.2τ, if there are no experimental conditions, T can be preset. i =5s, T d =1s as the initial value, and then fine-tune it according to the on-site debugging. Step 6: The electronically controlled exhaust valve 308 opens, and the compressed gas in the gas storage tank 90 flows to the outside through the dryer 304, the silencer 20 and the air filter 10. After time t, the valve closes.
[0025] During the process of releasing gas from the gas storage tank 90, the pressure sensor 403 detects the pressure P of the gas storage tank 90. If P is less than 1.0 MPa, the gas release will stop.
[0026] In addition, auxiliary control logic (1) Pressure protection: If the pressure in the gas storage tank is <1.0MPa during backflushing, backflushing shall be stopped immediately; (2) Speed-based air replenishment: Start the air pump when the vehicle speed is >30 km / h and the air tank pressure is <1.0 MPa, and stop when the pressure reaches 1.6 MPa; (3) Humidity triggering: Backflush when A > 80%RH at room temperature, and backflush when A > 70%RH at low temperature (<0℃); (4) Air pump protection: If the machine body temperature is >110℃ or continuous operation is >120S, the air pump will be turned off.
[0027] Specifically: When the vehicle is stationary, the air tank 90 is not replenished. When the vehicle is moving, wind noise and road noise will mask the sound of the air pump 30 working. At this time, the air tank 90 is replenished. Based on the vehicle speed, when the vehicle speed is >30 km / h and the pressure of the air tank 90 is less than 1.0 MPa, the air pump 30 is started. The air pump 30 works to inflate the air tank 90. When the pressure of the air tank 90 reaches 1.6 MPa, the air supply is stopped. When the humidity A of the drying tank 304 is greater than 80%RH, the system performs backflushing to dry the drying tank 304; The backflush control system also receives the ambient temperature signal from the vehicle via the CAN bus. When the ambient temperature is below zero and the humidity A of the dryer 304 is greater than 70%RH, the system will perform backflush.
[0028] This method can control the humidity of the drying tank to below 80%RH at room temperature and below 70%RH at low temperature, thus precisely controlling humidity, reducing energy consumption, and extending system life.
[0029] The above description is merely an illustrative embodiment of the invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the invention should fall within the scope of protection of the invention.
Claims
1. An air suspension system, comprising an air filter (10), a muffler (20), an air pump (30), and a gas distribution valve (40) connected in sequence, wherein the gas distribution valve (40) is connected to a left front air spring (50), a right front air spring (60), a left rear air spring (70), a right rear air spring (80), and an air tank (90), characterized in that: The air pump (30) includes a compressor (302) and a dryer (304). The silencer (20) is connected to the main line of the gas distribution valve (40) in sequence through the compressor (302), the dryer (304), and the dryer check valve (306). The pneumatic exhaust valve (309) has two air inlets. One of the two air inlets of the pneumatic exhaust valve (309) is connected to the main line of the gas distribution valve (40) through the electronically controlled exhaust valve (308). The other air inlet of the pneumatic exhaust valve (309) is connected to the pipeline between the compressor (302) and the dryer (304). The dryer (304) is connected to a humidity sensor (305). The single air outlet of the pneumatic exhaust valve (309) is connected to the pipeline between the silencer (20) and the compressor (302). The gas distribution valve (40) includes multiple air spring solenoid valves (401) and a gas tank solenoid valve (402). The main circuit of the gas distribution valve (40) is connected to the left front air spring (50), right front air spring (60), left rear air spring (70) and right rear air spring (80) through each corresponding air spring solenoid valve (401). The main circuit of the gas distribution valve (40) is connected to the gas tank (90) through the gas tank solenoid valve (402).
2. The air suspension system according to claim 1, characterized in that: The compressor (302) is driven by a motor (301), and the motor (301) is equipped with a temperature sensor (303).
3. An air suspension system according to claim 2, characterized in that: The outlet of the electrically controlled exhaust valve (308) is connected in one direction to the drying tank (304) and the drying check valve (306) through the backflush check valve (307).
4. An air suspension system according to claim 3, characterized in that: The gas storage tank (90) is also connected to a pressure sensor (403).
5. The method for controlling the humidity of the dryer tank of an air suspension system according to claim 4, characterized in that, Includes the following steps: The air pump (30) absorbs outside air, pressurizes it, and dries it through the drying tank (304). The dried gas is then sent into the storage tank (90) through the gas distribution valve (40). When the humidity in the drying tank (304) is too high, the storage tank (90) exhausts air in reverse, carrying away the water vapor in the drying tank (304) and discharging it to the outside.
6. The method for controlling the humidity of the dryer tank of an air suspension system according to claim 5, characterized in that, Specifically, the following steps are included: Step 1: The humidity sensor (305) detects the humidity of the drying tank (304) as A; Step 2: Pressure sensor (403) detects the pressure P of gas storage tank (90); Step 3: Set the humidity target SP of the drying tank (304) to 30%RH; Step 4: Compare the difference between the target humidity and the current humidity. The drying process follows an exponential decay law, and logarithmic error is used to control the backflushing time. Logarithmic error ; When A≤SP, the humidity requirement is met, so let e=0, backflushing time t=0, and do not start the backflushing process; When A > SP, e is a positive number, which is substituted into the PID formula to calculate the backflush time; Step 5: Calculate the backflush time t using the PID control method, as shown in the following formula: ;where K p For proportional gain, K i For integral gain, K d Let ∫edt be the differential gain, ∫edt be the cumulative integral of the error e over time, and de / dt be the rate of change of the derivative of the error e; K p The formula is related to the drying tank volume V1 and the average backflushing volumetric flow rate Q, and is as follows: ; V1 is the volume of the drying tank, C d , where A1 is the flow coefficient, ranging from 0.6 to 0.8, A1 is the cross-sectional area of the backflush pipe, in m², and P is the initial absolute pressure of the gas storage tank. atm The pressure is standard atmosphere, and ρ is the air density. K i =K p ×T i Where Ti is the integration time constant; K d =K p ×T d T d The differential time constant; The integral time constant Ti is taken as the system's dominant time constant τ, which is obtained by allowing the humidity inside the drying tank to naturally decrease from 80%RH to 30%RH, and recording the half-life t of the decrease process. 1 / 2 ,but Then let T i =τ,T d =0.2τ, if no experimental conditions are available, the preset T is 0.2τ. i =5s, T d =1s as the initial value, and then fine-tune it according to the on-site debugging. Step 6: The electronically controlled exhaust valve (308) is opened, and the compressed gas in the gas storage tank (90) flows to the outside through the dryer (304), silencer (20) and air filter (10), and is closed after time t.
7. The method for controlling the humidity of the dryer tank of an air suspension system according to claim 5, characterized in that: During the process of releasing gas from the gas storage tank (90), the pressure sensor (403) detects the pressure P of the gas storage tank (90). If P is less than 1.0 MPa, the gas release is stopped.
8. The method for controlling the humidity of the dryer tank of an air suspension system according to claim 5, characterized in that: When the vehicle is stationary, the air tank (90) is not replenished. When the vehicle is moving, wind noise and road noise will cover the sound of the air pump (30) working. At this time, the air tank (90) is replenished. Based on the vehicle speed, when the vehicle speed is >30Km / h and the pressure of the air tank (90) is less than 1.0MPa, the air pump (30) is started. The air pump (30) works to fill the air tank (90) with air. When the pressure of the air tank (90) reaches 1.6MPa, the air supply is stopped.
9. A method for controlling the humidity of a dryer tank in an air suspension system according to claim 5, characterized in that: When the humidity A of the drying tank (304) is greater than 80%RH, the system performs backflushing to dry the drying tank (304).
10. A method for controlling the humidity of a dryer tank in an air suspension system according to claim 5, characterized in that: The backflush control system also receives the ambient temperature signal from the vehicle via the CAN bus. When the ambient temperature is below zero and the humidity A of the dryer (304) is greater than 70%RH, the system will perform backflush.