A method and system for testing components of an electronically controlled air suspension system

Abstract

The present application discloses a method and system for testing components of an electronically controlled air suspension system, and relates to the technical field of suspension system performance testing, which includes an air spring testing step, which includes: selecting a plurality of air pressure values ​​in sequence as a set of loads for the air spring according to the working air pressure range of the air spring; applying a corresponding constant force to the air spring at the initial state corresponding to each load of the air spring, respectively, to perform air spring inflation and deflation tests, and then obtaining the inflation flow and height of the air spring at each sampling moment, as well as the deflation flow and height of the air spring, and thereby constructing a corresponding load-flow-height inflation model and a load-flow-height deflation model. The testing method and system of the present application can not only obtain the relationship between the inflation and deflation volume and the change in the height of the air spring under different loads, but also present the test results using a mathematical model.

Description

Technical Field

[0001] The present application relates to the technical field of suspension system performance testing, and in particular to a method and system for testing components of an electronically controlled air suspension system. Background Art

[0002] At present, with the rapid development of vehicle electronic control technology, low-cost and high-performance automotive electronic control devices have become popular, and the air suspension system has also ushered in the era of electronic control. Among them, the ECAS (Electronic Control Air Suspension) system has gradually been recognized by the market for its superior stiffness control, comfort, driving smoothness and operational stability. The ECAS system has been widely used in the fields of high-end buses and tourist coaches, as well as commercial vehicles.

[0003] In the related technology, the solenoid valve and the air spring are the key components of the ECAS system, which play a decisive role in the performance of the entire electronically controlled air suspension system. However, there is currently no method or test bench system for the solenoid valve and the air spring of the ECAS system. Summary of the invention

[0004] In view of one of the defects existing in the prior art, the purpose of the present application is to provide a method and system for testing components of an electronically controlled air suspension system, so as to solve the problem in the related art of lacking a method and a test bench system for reasonably testing the air springs of the ECAS system.

[0005] A first aspect of the present application provides a method for testing components of an electronically controlled air suspension system, which includes an air spring testing step, wherein the air spring testing step includes:

[0006] According to the working air pressure range of the air spring, multiple air pressure values ​​are selected in sequence as a set of loads of the air spring;

[0007] At the initial state corresponding to each load of the air spring, a corresponding constant force is applied to the air spring, and the air spring is deflated through the solenoid valve to make it drop to the lowest height, and then the air spring is inflated to make it rise from the lowest height to the highest height, and the inflation flow and height of the air spring at each sampling moment are obtained, and then the corresponding load-flow-height inflation model is constructed;

[0008] In the initial state corresponding to each load of the air spring, a corresponding constant force is applied to the air spring. The air spring is inflated through the solenoid valve to make it rise to the maximum height. Then, the air spring is deflated to make it drop from the maximum height to the minimum height. The deflation flow and height of the air spring at each sampling moment are obtained, and then the corresponding load-flow-height deflation model is constructed.

[0009] In some embodiments, after selecting a plurality of air pressure values ​​as a set of loads of the air spring in sequence according to the working air pressure range of the air spring, the method further includes determining the filling duty ratio of the solenoid valve under each load; determining the filling duty ratio of the solenoid valve under any load includes:

[0010] Determine the inflation drive cycle of the solenoid valve, and apply a corresponding constant force to the air spring under the initial state corresponding to the load, deflate the air spring to make it drop to the lowest height, and then inflate the air spring at different duty ratios to make the air spring rise from the lowest height to the highest height, and record the rising time corresponding to each duty ratio;

[0011] The duty cycle of the rise time within the first preset time range is selected as the charging duty cycle of the solenoid valve under the load.

[0012] In some embodiments, after selecting a plurality of air pressure values ​​as a set of loads of the air spring in sequence according to the working air pressure range of the air spring, the process further includes determining the deflation duty ratio of the solenoid valve under each load; determining the deflation duty ratio of the solenoid valve under any load includes:

[0013] Determine the deflation drive cycle of the solenoid valve, and apply a corresponding constant force to the air spring under the initial state corresponding to the load, inflate the air spring to make it rise to the highest height, and then deflate the air spring at different duty ratios to make the air spring drop from the highest height to the lowest height, and record the drop time corresponding to each duty ratio;

[0014] The duty cycle of the falling time within the second preset time range is selected as the degassing duty cycle of the solenoid valve under the load.

[0015] In some embodiments, the initial state of the air spring corresponding to any load is: the air spring is at a preset height, and the air pressure inside the air spring is the air pressure value corresponding to the load.

[0016] In some embodiments, the constant force applied to the air spring is applied by a hydraulic cylinder;

[0017] In the initial state corresponding to any load of the air spring, a corresponding constant force is applied to the air spring, specifically including:

[0018] Adjust the hydraulic cylinder until the air spring is in the initial state, and use the hydraulic pressure of the hydraulic press at this time as the constant force.

[0019] In some embodiments, when the air spring rises or falls, a preset stabilization time is provided between two adjacent solenoid valve driving cycles.

[0020] In some embodiments, before the air spring testing step, a solenoid valve testing step is also included, and the solenoid valve testing step includes:

[0021] The solenoid valve is tested for operating frequency, opening condition, response time and flow rate respectively, and the test results are used as parameters to characterize the characteristics of the solenoid valve.

[0022] In some embodiments, the operating frequency test includes: obtaining outlet flow values ​​corresponding to different duty cycles of the solenoid valve at different operating frequencies;

[0023] The above-mentioned opening condition test includes: gradually increasing the duty cycle at different inlet air pressures of the solenoid valve to obtain the outlet air pressure values ​​at different duty cycles, and obtaining the minimum duty cycle when the outlet air pressure value suddenly changes at each inlet air pressure; the outlet air pressure value suddenly changes when the above-mentioned outlet air pressure value is greater than 10% of the inlet air pressure for the first time; the minimum inlet air pressure when the outlet air pressure value suddenly changes at the maximum duty cycle is the solenoid valve opening pressure;

[0024] The above response time test includes: obtaining the response time of the solenoid valve under different inlet air pressures;

[0025] The flow test includes: obtaining the outlet flow values ​​corresponding to different duty cycles of the solenoid valve under different gas source pressures.

[0026] The second aspect of the present application provides an electronically controlled air suspension system component testing system for implementing the above method, comprising:

[0027] A controllable air source, which is connected to the inlet of the solenoid valve and is used to provide a stable air source for the solenoid valve;

[0028] An electronic control unit ECU, which is electrically connected to the solenoid valve;

[0029] When testing air springs, the above system also includes:

[0030] A flow meter group, comprising a first flow meter and a second flow meter for respectively collecting flows at two outlets of the solenoid valve;

[0031] A hydraulic cylinder for applying a constant load to the air spring;

[0032] The two outlets of the electromagnetic valve are connected to two air springs through a first flow meter and a second flow meter respectively, and a height sensor is provided on each air spring;

[0033] The ECU is respectively connected to the first flow meter, the second flow meter and the height sensor signal through the signal collector; the ECU is used to send a control signal to the solenoid valve to be tested so as to inflate or deflate the air spring.

[0034] In some embodiments, the test method further includes a solenoid valve test step before performing the air spring test step, and the solenoid valve test step includes: when it is determined that the solenoid valve has no fault, performing an operating frequency test, an opening condition test, a response time test, and a flow test on the solenoid valve respectively;

[0035] When performing solenoid valve testing, the above system also includes:

[0036] An air pressure sensor group, comprising a first air pressure sensor for collecting air pressure at the inlet of the solenoid valve, and a second air pressure sensor and a third air pressure sensor for collecting air pressure at two outlets of the solenoid valve respectively; the above-mentioned ECU is connected to the air pressure sensor group through a signal collector;

[0037] When performing the working frequency test and flow test of the solenoid valve, the system further includes a first flow meter and a second flow meter for respectively collecting the flow at the two outlets of the solenoid valve, and the ECU is respectively connected to the first flow meter and the second flow meter signals through the signal collector.

[0038] The beneficial effects of the technical solution provided by this application include:

[0039] The electronically controlled air suspension system component testing method and system of the present application can select multiple air pressure values ​​in turn as a set of loads for the air spring according to the working air pressure range of the air spring, and then apply a corresponding constant force to the air spring in the initial state corresponding to each load of the air spring to perform air spring inflation and deflation tests, thereby obtaining the inflation flow and height of the air spring at each sampling moment, as well as the deflation flow and height of the air spring, and thereby constructing the corresponding load-flow-height inflation model and load-flow-height deflation model; therefore, not only can the relationship between the inflation and deflation volume and the change in the height of the air spring under different loads be obtained, but also the test results can be presented using a mathematical model. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a flow chart of a method for testing components of an electronically controlled air suspension system in this embodiment;

[0042] Figure 2 is a contour diagram of the inflation characteristics of the air spring in this embodiment;

[0043] Figure 3is a load-flow-height inflation model of the inflation characteristics of the air spring in this embodiment;

[0044] Figure 4 is a load-flow-height deflation model of the deflation characteristics of the air spring in this embodiment;

[0045] Figure 5 is a first schematic diagram of the electronically controlled air suspension system component testing system in this embodiment;

[0046] Figure 6 is a second schematic diagram of the electronically controlled air suspension system component testing system in this embodiment;

[0047] Figure 7 is a third schematic diagram of the electronically controlled air suspension system component testing system in this embodiment;

[0048] Figure 8 This is the fourth principle diagram of the electronically controlled air suspension system component testing system in this embodiment. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present application clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] like Figure 1 As shown, the embodiment of the present application provides a method for testing components of an electronically controlled air suspension system, which is used for testing the characteristics of components of an electronically controlled air suspension system of a commercial vehicle. The testing method includes an air spring testing step, which includes:

[0051] S1. According to the working air pressure range of the air spring, multiple air pressure values ​​are selected in sequence as a set of loads of the air spring, wherein each load of the air spring corresponds to each initial state pressure of the air spring.

[0052] S2. Apply a corresponding constant force to the air spring at the initial state corresponding to each load of the air spring, deflate the air spring through the solenoid valve to make it drop to the minimum height, then inflate the air spring to make it rise from the minimum height to the maximum height, and obtain the inflation flow and height of the air spring at each sampling moment, and then construct a load-flow-height inflation model corresponding to the air spring inflation.

[0053] S3. Apply a corresponding constant force to the air spring at the initial state corresponding to each load of the air spring, inflate the air spring through the solenoid valve to make it rise to the maximum height, then deflate the air spring to make it drop from the maximum height to the minimum height, and obtain the deflation flow and height of the air spring at each sampling moment, and then construct a load-flow-height deflation model corresponding to the deflation of the air spring.

[0054] Among them, each sampling moment can be set according to actual needs.

[0055] The electronically controlled air suspension system component testing method of the present embodiment can select multiple air pressure values ​​in turn as a set of loads for the air spring according to the working air pressure range of the air spring, and then apply corresponding constant forces to the air spring in the initial state corresponding to each load of the air spring to perform air spring inflation and deflation tests, thereby obtaining the inflation flow and height of the air spring at each sampling moment, as well as the deflation flow and height of the air spring, and thereby constructing corresponding load-flow-height inflation model and load-flow-height deflation model; therefore, not only the relationship between the inflation and deflation volume and the change in the height of the air spring under different loads, that is, the characteristics of the air spring, can be obtained, but also the test results can be presented using a mathematical model, that is, the relationship between the load, expansion and contraction amount, and inflation and deflation flow of the air spring can be characterized.

[0056] Optionally, the above test results can also be used for a vehicle height control model based on the air spring height change and the solenoid valve flow model.

[0057] Based on the above embodiments, in this embodiment, after selecting multiple air pressure values ​​in turn as a set of loads of the air spring according to the working air pressure range of the air spring, it also includes determining the inflation duty cycle of the solenoid valve under each load and the deflation duty cycle of the solenoid valve under each load.

[0058] Specifically, determining the charging duty cycle of the solenoid valve under any load specifically includes the following steps:

[0059] First, determine the inflation drive cycle of the solenoid valve, and apply a corresponding constant force to the air spring in the initial state corresponding to the load of the air spring. Deflate the air spring through the solenoid valve to make it drop to the minimum height, and then inflate the air spring at different duty ratios to make the air spring rise from the minimum height to the maximum height. Record the rising time corresponding to each duty ratio under the load, that is, the time taken for the air spring to rise from the minimum height to the maximum height under the load.

[0060] Then, the duty cycle of the rise time within the first preset time range is selected as the inflation duty cycle of the solenoid valve under the load. In this embodiment, the first preset time range is 20-30 times the inflation drive cycle.

[0061] Further, determining the deflation duty ratio of the solenoid valve under any load specifically includes the following steps:

[0062] First, determine the deflation drive cycle of the solenoid valve, and apply the corresponding constant force to the air spring in the initial state corresponding to the load of the air spring. Inflate the air spring through the solenoid valve to make it rise to the maximum height, and then deflate the air spring at different duty ratios to make the air spring drop from the maximum height to the minimum height. Record the descent time corresponding to each duty ratio under the load, that is, the time taken for the air spring to drop from the maximum height to the minimum height under the load.

[0063] Then, the duty cycle of the falling time within the second preset time range is selected as the deflation duty cycle of the electromagnetic valve under the load. In this embodiment, the second preset time range is 20-30 times of the deflation drive cycle.

[0064] On the basis of the above-mentioned embodiment, in this embodiment, the initial state corresponding to any load of the above-mentioned air spring is: the air spring is at a preset height, and the internal air pressure thereof is the air pressure value corresponding to the load.

[0065] Furthermore, the constant force on the air spring is applied by a hydraulic cylinder. In the initial state corresponding to any load of the air spring, the corresponding constant force is applied to the air spring, specifically including:

[0066] Adjust the hydraulic cylinder to the initial state of the air spring corresponding to the load, and use the hydraulic pressure of the hydraulic press at this time as the constant force corresponding to the load. The hydraulic press can then move up and down as the air spring is inflated and deflated, while keeping the hydraulic pressure constant.

[0067] On the basis of the above-mentioned embodiment, when the above-mentioned air spring rises or falls, a preset stabilization time is provided between two adjacent solenoid valve driving cycles, so as to obtain a more realistic inflation flow and height change.

[0068] Optionally, the stabilization time between two adjacent inflation drive cycles and the stabilization time between two adjacent deflation drive cycles are both 15 seconds.

[0069] Optionally, the inflation drive cycle is the same as the deflation drive cycle. In this embodiment, the inflation drive cycle and the deflation drive cycle are both 300ms to meet the technical requirements of this test: ① the vehicle height switching is completed within 3s; ② the adjustment process is smooth without convex changes.

[0070] In this embodiment, a 6×2 vehicle with 9 air springs is taken as an example, and the working air pressure range of the air spring is 0.5-8.5 bar. A series of initial states of the air springs are selected according to the air pressure range, that is, a set of loads is selected: increasing from 0.5 to 8.5 bar at a step length of 0.5 bar.

[0071] During the inflation test, a corresponding constant force is applied to the air spring in the initial state corresponding to each load (the preset height is 295mm). Select the fixed cycle of the solenoid valve of 300ms (fixed cycle and duty cycle, it is necessary to ensure that the inflation speed is moderate), deflate the air spring to make it drop to the minimum height, and then inflate the air spring with the inflation duty cycle of the solenoid valve under the load, so that it rises from the minimum height (230mm) to the maximum height (390mm), and record the inflation flow and height of the air spring in each solenoid valve inflation drive cycle in turn.

[0072] During the deflation test, a corresponding constant force is applied to the air spring in the initial state corresponding to each load (the preset height is 295mm). The fixed cycle of the solenoid valve is selected to be 300ms, and the air spring is inflated to make it rise to the highest height. Then, the air spring is inflated with the deflation duty cycle of the solenoid valve under the load to make it drop from the highest height to the lowest height. The deflation flow and height of the air spring in each solenoid valve deflation drive cycle are recorded in turn.

[0073] This embodiment can obtain the amount of gas required for each 1 mm change in the air spring height under different loads, as well as the change in the equivalent cross-sectional area of ​​the air spring with height and air pressure, which can be used to establish an air spring simulation model.

[0074] The contour diagram of the inflation characteristics of the air spring is as follows: Figure 2 As shown, the load-flow-height inflation model of the air spring inflation characteristics is as follows Figure 3 As shown in Figure 2, the load-flow-height deflation model of the air spring deflation characteristics is as follows: Figure 4 Through these two mathematical models, the amount of gas required for inflation and deflation for each 1mm change in the air spring height under any state can be obtained.

[0075] In addition, under the same air intake volume, the height change of the air spring is different, which indicates that as the height of the air spring changes, the equivalent cross-sectional area of ​​the air spring is constantly changing, and the greater the height of the air spring, the smaller its equivalent cross-sectional area.

[0076] When the air spring is compressed and pulled to a large extent, the height of the air spring changes slowly, that is, when the same gas is filled, the height change of the air spring is small, which is called the insensitive area of ​​the air spring height change. In this embodiment, when the air spring height is in the range of 260-300mm, the air spring height changes more slowly, which is the insensitive area of ​​the air spring height change.

[0077] In this embodiment, in the three gear adjustment ranges of the whole vehicle, that is, the airbag height is within the range of 265-325mm, the air spring height change is approximately linearly related to the inflation amount, which is beneficial for the height control of the whole vehicle. In addition, since the 9 air spring model is equipped with a small air spring, the three vehicle height control targets are 265mm, 295mm, and 325mm, respectively, which intersect with the insensitive area of ​​the small air spring height change.

[0078] On the basis of the above embodiment, in this embodiment, before the air spring testing step, a solenoid valve testing step is also included.

[0079] Preferably, the test step can be used for a single-channel solenoid valve or a dual-channel solenoid valve. Both the single-channel solenoid valve and the dual-channel solenoid valve include one inlet and two outlets. The single-channel solenoid valve and the dual-channel solenoid valve have the same appearance. The difference between the two is that the single-channel solenoid valve can simultaneously realize the charging and deflating of two outlet channels by sending one control signal, while the dual-channel solenoid valve needs to send two control signals to control the charging and deflating of the two outlet channels respectively. Therefore, the test methods of the two are the same.

[0080] In this embodiment, the solenoid valve testing steps include:

[0081] The solenoid valve is tested for operating frequency, opening condition, response time and flow rate respectively, and the test results are used as parameters to characterize the characteristics of the solenoid valve. During each test, one outlet channel of the solenoid valve is tested and the other outlet channel is closed.

[0082] The solenoid valve test of this embodiment can obtain parameters that can characterize the characteristics of the solenoid valve, and then use them to build a solenoid valve simulation model.

[0083] Specifically, the solenoid valve operating frequency test is intended to test the performance of the solenoid valve at different operating frequencies and determine the solenoid valve operating frequency that meets system requirements. The reciprocal of the solenoid valve operating frequency is the solenoid valve drive cycle. Since the solenoid valve is controlled by PWM wave, the opening time of a single drive cycle of the solenoid valve is the product of the drive cycle and the duty cycle.

[0084] The operating frequency test includes: obtaining the outlet flow values ​​corresponding to different duty cycles of the solenoid valve at different operating frequencies, recording the data and analyzing the operating frequency of the solenoid valve, so as to determine the minimum opening time of the solenoid valve.

[0085] Among them, the duty cycle of the solenoid valve can be set to 50% in advance, and its operating frequency increases continuously from low to high, and the changes in the outlet flow are recorded and observed. If the flow at the outlet is 0, it means that the solenoid valve frequency is too high or the solenoid valve opening time is too short, and the valve cannot respond in time, resulting in the solenoid valve unable to open normally.

[0086] Then, at each operating frequency, the duty cycle was increased from 20% to 80% in steps of 10% to obtain different outlet flow rates.

[0087] In the test of this embodiment, taking the dual-channel solenoid valve as an example, when the fixed duty cycle of the dual-channel solenoid valve is set to 50%, when the driving cycle is reduced to 100ms, the solenoid valve cannot be opened normally, and when the cycle is given to 110ms, the solenoid valve can just open, and the minimum opening time of the solenoid valve can be determined to be 55ms. In addition, if the solenoid valve driving cycle is small, the duty cycle adjustable range is too small, and the solenoid valve opens and closes too frequently; if the solenoid valve driving cycle is large, such as 1000ms, when meeting the same flow demand, the adjustable duty cycle of the solenoid valve is small, and the adjustment time is too long, or the adjustment cycle is too small, and the system jitter is obvious.

[0088] Among them, when the solenoid valve has a cycle of 300ms, the flow value within the adjustable duty cycle range can meet the filling and deflation flow requirements of the air spring. The duty cycle can be adjusted in a wide range and meets the requirements of various control strategies.

[0089] The above-mentioned solenoid valve opening condition test is aimed at studying the minimum values ​​of the solenoid valve inlet air pressure and opening time that can meet its normal operation. That is, when the ECU sends a solenoid valve opening signal, it tests whether there will be a sudden change in the air pressure at the solenoid valve outlet under different solenoid valve inlet air pressures, that is, whether the solenoid valve is opened, so as to obtain the air pressure and duty cycle (fixed cycle) requirements for the opening of the solenoid valve, that is, to determine the normal operating range of the solenoid valve, so as to facilitate the construction of the solenoid valve simulation model and the design of the control strategy.

[0090] The opening condition test includes: gradually increasing the duty cycle at different inlet pressures of the solenoid valve to obtain the outlet pressure values ​​at different duty cycles, and obtaining the minimum duty cycle when the outlet pressure value suddenly changes at each inlet pressure (when the cycle is fixed, it can be equivalent to the minimum opening time of the solenoid valve). The outlet pressure value suddenly changes when the outlet pressure value is greater than 10% of the inlet pressure for the first time.

[0091] Optionally, the inlet air pressure of the solenoid valve may be increased from 1 bar to 12.5 bar at a step length of 0.5 KPa; the duty cycle may be increased from 20% to 80% at a step length of 10%.

[0092] The test process can also obtain the minimum inlet pressure when the outlet pressure value suddenly changes under the maximum duty cycle as the solenoid valve opening pressure. Optionally, the maximum duty cycle can be 100%, or the maximum value of 80% of the duty cycle set during the opening condition test.

[0093] In the test of this embodiment, for the same solenoid valve channel, the greater the inlet air pressure and the greater the duty cycle, the easier it is for the valve to open; in addition, since the air source pressure in the vehicle ECAS system is 10-12.5 bar, the solenoid valve duty cycle signal can be controlled to be greater than 25% (fixed period 300ms) to avoid the influence of the solenoid valve opening condition.

[0094] Furthermore, the response time test of the solenoid valve can obtain the response time of the solenoid valve under different inlet air pressures, so as to facilitate the construction of the solenoid valve simulation model and the design of the control strategy.

[0095] Among them, the response time test of the solenoid valve includes:

[0096] Test the response time of the solenoid valve under different inlet air pressures, that is, the time required from the ECU sending a solenoid valve opening command to the solenoid valve opening.

[0097] In this embodiment, the ECU sends a signal to the solenoid valve, and after a certain period of time, the air pressure at the outlet of the solenoid valve changes suddenly until it stabilizes, and the outlet air pressure curve is obtained at the same time.

[0098] Among them, based on the outlet air pressure curve that changes with time, the time point when the ECU issues the solenoid valve opening command is taken as the reference time t0, and the time point when the outlet air pressure is 10% of the outlet stable air pressure (a sudden change in outlet air pressure) is taken as the response end time. The time difference between the response end time and the reference time is the solenoid valve response time.

[0099] In the test of this embodiment, the greater the inlet pressure of the solenoid valve, the faster the valve response speed, and there is a difference in the response time of the two outlet channels of the same solenoid valve. Among them, the difference is larger in the dual-channel solenoid valve, and smaller in the single-channel solenoid valve. Since the air source pressure of the whole vehicle is generally 10-12.5bar, the response time difference of the two outlet channels of the solenoid valve is 10ms at this time. Therefore, the difference in the single-channel solenoid valve has limited impact on the control of the whole vehicle, and no roll phenomenon occurred in the early actual vehicle debugging, which can be ignored.

[0100] The flow test of the above-mentioned solenoid valve is intended to obtain the gas flow data of the two outlet channels of the dual-channel solenoid valve and the single-channel solenoid valve during the filling and deflation processes at different duty cycles and different pressure differences, so as to be used for the simulation of the electronically controlled air suspension system and the vehicle height control based on the air spring height change and the solenoid valve flow model.

[0101] The flow test of the solenoid valve includes: obtaining the outlet flow values ​​of the solenoid valve corresponding to different duty cycles under different gas source pressures.

[0102] Specifically, the flow test includes an inflation flow test and a deflation flow test. During the inflation flow test, the inlet channel of the solenoid valve is connected to the inflation gas source, and the two outlet channels are connected to the atmosphere through the air pressure sensor and the flow meter respectively. At this time, the inflation gas source supplies gas, enters through the inlet channel of the solenoid valve, and exhausts from the outlet channel of the solenoid valve to be tested.

[0103] During the deflation flow test, the inlet channel of the solenoid valve is disconnected from the inflation gas source, and the two outlet channels are connected to the deflation gas source through the air pressure sensor and the flow meter respectively. The two flow meters can monitor the flow changes over time at the two outlets respectively. At this time, the deflation gas source supplies gas, enters through the outlet channel of the solenoid valve, and exhausts from the exhaust port of the solenoid valve itself. Each gas source is connected to an inflation pump, and the gas source pressure can be stabilized by the inflation pump.

[0104] In this embodiment, the air source pressure, i.e., the air inlet pressure of the solenoid valve, can be increased from 1 bar to 8.5 bar at a step length of 0.5 bar; the duty cycle can be increased from 20% to 100% at a step length of 5%. For each set of data, the corresponding flow rate is the average flow rate in the stable flow stage.

[0105] In the test of this embodiment, during the inflation process, as the air pressure and duty cycle increase, the flow rate of the solenoid valve single-cycle injection gradually increases (unit: L-standard conditions), and for the same solenoid valve, the flow rate of outlet channel 1 is larger than that of outlet channel 2 under the same working conditions, but the flow difference between the two channels of the solenoid valve has limited effect on the control of the entire vehicle.

[0106] During the deflation process, the flow rate of a single-cycle injection of the solenoid valve is significantly affected by the change in duty cycle. For the outlet channel 1 of the dual-channel solenoid valve, there is a critical air pressure value (approximately 6.5 bar) in the area above a duty cycle of 40% during the deflation process. When the inlet air pressure exceeds 6.5 bar, the deflation flow rate will increase rapidly. This characteristic did not appear in the deflation test of outlet channel 2. In addition, the operating air pressure range of the vehicle air spring is 0.5-8.5 bar. When the internal air pressure of the air spring is greater than 6.5 bar, the deflation rates of outlet channel 1 and outlet channel 2 of the solenoid valve are quite different.

[0107] like Figure 5 As shown, an embodiment of the present application also provides an electronically controlled air suspension system component testing system for implementing the above method, and the testing system can be used for solenoid valve testing and air spring testing.

[0108] In this embodiment, the test system includes a controllable gas source and an electronic control unit ECU.

[0109] The controllable air source is connected to the inlet of the solenoid valve to provide a stable air source for the solenoid valve. The ECU is electrically connected to the solenoid valve. The solenoid valve is provided with an inlet channel 0, an outlet channel 1 and an outlet channel 2.

[0110] Optionally, the controllable air source is a stable pressure controllable air source. A stop valve may be provided between the controllable air source and the electromagnetic valve. The stop valve may connect or cut off the passage between the controllable air source and the electromagnetic valve.

[0111] When the air spring is tested, the system further includes a flow meter group and a hydraulic cylinder. The flow meter group includes a first flow meter and a second flow meter for respectively collecting the flow at the two outlets of the solenoid valve. The hydraulic cylinder is used to apply a constant load to the air spring.

[0112] Optionally, the flow meter has a range of 30-3000 L / min.

[0113] The two outlets of the electromagnetic valve are connected to two air springs through a first flow meter and a second flow meter respectively, and a height sensor is arranged on each air spring.

[0114] In this embodiment, the two air springs are of the same model, and the solenoid valve is preferably a single-channel solenoid valve.

[0115] The ECU is connected to the first flow meter, the second flow meter and the height sensor signals respectively through a signal collector; optionally, the signal collector has a collection frequency of 10 Hz. The ECU is used to send a control signal to the solenoid valve to be tested to inflate or deflate the air spring. The ECU is also used to obtain the inflation flow and height of the air spring at each sampling moment, as well as the deflation flow and height of the air spring at each sampling moment.

[0116] Optionally, when performing an air spring test, the above system may also include an air pressure sensor group connected to the signal collector, the air pressure sensor group including a first air pressure sensor P1 for collecting the air pressure at the inlet of the solenoid valve, and a second air pressure sensor P2 and a third air pressure sensor P3 for respectively collecting the air pressures at the two outlets of the solenoid valve.

[0117] Furthermore, the above-mentioned testing method also includes a solenoid valve testing step before performing the air spring testing step. The above-mentioned solenoid valve testing step includes: when it is determined that the solenoid valve has no faults, performing an operating frequency test, an opening condition test, a response time test and a flow test on the above-mentioned solenoid valve respectively.

[0118] like Figure 6 As shown, when the solenoid valve is tested, the system further includes an air pressure sensor group. The air pressure sensor group includes a first air pressure sensor P1 for collecting air pressure at the inlet of the solenoid valve, and a second air pressure sensor P2 and a third air pressure sensor P3 for collecting air pressure at two outlets of the solenoid valve respectively; the ECU is connected to the air pressure sensor group through a signal collector.

[0119] Therefore, when performing the solenoid valve operating frequency test, opening condition test, response time test and flow test, an air pressure sensor group is required.

[0120] In this embodiment, when the opening condition test and the response time test of the solenoid valve are performed, the two outlets of the solenoid valve need to be closed respectively, and there is no need to connect a flow meter.

[0121] like Figure 7 As shown, when the working frequency test of the solenoid valve and the inflation flow test in the flow test are performed, the system further includes a first flow meter and a second flow meter for respectively collecting the flow at the two outlets of the solenoid valve. At this time, the two outlets of the solenoid valve are connected to the atmosphere through the first flow meter and the second flow meter respectively. The ECU is also connected to the first flow meter and the second flow meter through the signal collector.

[0122] When the solenoid valve is tested, the ECU is used to send a test signal to the solenoid valve so as to perform an operating frequency test, an opening condition test, a response time test and a flow test on the solenoid valve.

[0123] like Figure 8 As shown, when the deflation flow test in the flow test is performed, the inlet channel 0 of the solenoid valve can be disconnected from the controllable air source (i.e., the inflation air source), and the two outlet channels 1 and 2 are connected to the deflation air source via the air pressure sensor and the flow meter respectively.

[0124] The electronically controlled air suspension system component testing system of the present embodiment is applicable to each of the above-mentioned electronically controlled air suspension system component testing methods. It can not only perform air spring characteristic tests to obtain the relationship between the inflation and deflation volume and the change in air spring height under different air spring loads for building an air spring mathematical model, but also perform solenoid valve characteristic tests to obtain parameters characterizing the solenoid valve characteristics for building a solenoid valve simulation model.

[0125] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0126] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0127] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for testing components of an electronically controlled air suspension system, characterized in that: It includes an air spring testing step, and the air spring testing step includes: According to the working air pressure range of the air spring, multiple air pressure values ​​are selected in sequence as a set of loads of the air spring; At the initial state corresponding to each load of the air spring, a corresponding constant force is applied to the air spring, and the air spring is deflated through the solenoid valve to make it drop to the lowest height, and then the air spring is inflated to make it rise from the lowest height to the highest height, and the inflation flow and height of the air spring at each sampling moment are obtained, and then the corresponding load-flow-height inflation model is constructed; In the initial state corresponding to each load of the air spring, a corresponding constant force is applied to the air spring. The air spring is inflated through the solenoid valve to make it rise to the maximum height. Then, the air spring is deflated to make it drop from the maximum height to the minimum height. The deflation flow and height of the air spring at each sampling moment are obtained, and then the corresponding load-flow-height deflation model is constructed.

2. The electronically controlled air suspension system component testing method according to claim 1, characterized in that: After selecting a plurality of air pressure values ​​as a set of loads of the air spring in sequence according to the working air pressure range of the air spring, the method further includes determining the filling duty ratio of the solenoid valve under each load; Determining the solenoid valve charging duty cycle at any load includes: Determine the inflation drive cycle of the solenoid valve, and apply a corresponding constant force to the air spring under the initial state corresponding to the load, deflate the air spring to make it drop to the lowest height, and then inflate the air spring at different duty ratios to make the air spring rise from the lowest height to the highest height, and record the rising time corresponding to each duty ratio; The duty cycle of the rise time within the first preset time range is selected as the charging duty cycle of the solenoid valve under the load.

3. The electronically controlled air suspension system component testing method according to claim 1, characterized in that: After selecting a plurality of air pressure values ​​as a set of loads of the air spring in sequence according to the working air pressure range of the air spring, the method further includes determining the degassing duty ratio of the solenoid valve under each load; Determining the bleed duty cycle of the solenoid valve at any load includes: Determine the deflation drive cycle of the solenoid valve, and apply a corresponding constant force to the air spring under the initial state corresponding to the load, inflate the air spring to make it rise to the highest height, and then deflate the air spring at different duty ratios to make the air spring drop from the highest height to the lowest height, and record the drop time corresponding to each duty ratio; The duty cycle of the falling time within the second preset time range is selected as the degassing duty cycle of the solenoid valve under the load.

4. The electronically controlled air suspension system component testing method according to claim 1, characterized in that: The initial state of the air spring corresponding to any load is: the air spring is at a preset height, and its internal air pressure is the air pressure value corresponding to the load.

5. The electronically controlled air suspension system component testing method according to claim 4, characterized in that: The constant force on the air spring is applied by a hydraulic cylinder; In the initial state corresponding to any load of the air spring, a corresponding constant force is applied to the air spring, specifically including: Adjust the hydraulic cylinder until the air spring is in the initial state, and use the hydraulic pressure of the hydraulic press at this time as the constant force.

6. The electronically controlled air suspension system component testing method according to claim 1, characterized in that: When the air spring rises or falls, a preset stabilization time is provided between two adjacent solenoid valve driving cycles.

7. The electronically controlled air suspension system component testing method according to claim 1, characterized in that: Before the air spring test step, a solenoid valve test step is also included, and the solenoid valve test step includes: The solenoid valve is respectively subjected to an operating frequency test, an opening condition test, a response time test and a flow rate test, and the test results obtained are used as parameters characterizing the characteristics of the solenoid valve.

8. The electronically controlled air suspension system component testing method according to claim 7, characterized in that: The working frequency test includes: obtaining the outlet flow values ​​corresponding to different duty cycles of the solenoid valve at different working frequencies; The opening condition test includes: gradually increasing the duty cycle at different inlet pressures of the solenoid valve to obtain outlet pressure values ​​at different duty cycles, and obtaining the minimum duty cycle when the outlet pressure value suddenly changes at each inlet pressure; the outlet pressure value suddenly changes when the outlet pressure value is greater than 10% of the inlet pressure for the first time; the minimum inlet pressure when the outlet pressure value suddenly changes at the maximum duty cycle is the solenoid valve opening pressure; The response time test includes: obtaining the response time of the solenoid valve under different inlet air pressures; The flow test includes: obtaining outlet flow values ​​corresponding to different duty cycles of the solenoid valve under different air source pressures.

9. An electronically controlled air suspension system component testing system for implementing the method of claim 1, characterized in that: It includes: A controllable air source, which is connected to the inlet of the solenoid valve and is used to provide a stable air source for the solenoid valve; An electronic control unit ECU, which is electrically connected to the solenoid valve; When performing an air spring test, the system further comprises: A flow meter group, comprising a first flow meter and a second flow meter for respectively collecting flows at two outlets of the solenoid valve; a hydraulic cylinder for applying a constant load to the air spring; The two outlets of the solenoid valve are connected to two air springs through a first flow meter and a second flow meter respectively, and a height sensor is provided on each air spring; The ECU is respectively connected to the first flow meter, the second flow meter and the height sensor signal through the signal collector; the ECU is used to send a control signal to the electromagnetic valve to be tested to inflate or deflate the air spring.

10. The electronically controlled air suspension system component testing system according to claim 9, characterized in that: The test method further includes a solenoid valve test step before performing the air spring test step, and the solenoid valve test step includes: when it is determined that the solenoid valve has no fault, performing a working frequency test, an opening condition test, a response time test and a flow test on the solenoid valve respectively; When performing a solenoid valve test, the system further comprises: An air pressure sensor group, comprising a first air pressure sensor for collecting air pressure at the inlet of the solenoid valve, and a second air pressure sensor and a third air pressure sensor for collecting air pressure at two outlets of the solenoid valve respectively; the ECU is connected to the air pressure sensor group through a signal collector; When performing the working frequency test and flow test of the solenoid valve, the system also includes a first flowmeter and a second flowmeter for respectively collecting flows at two outlets of the solenoid valve, and the ECU is respectively connected to the first flowmeter and the second flowmeter through a signal collector.

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