Method for detecting residual air in a hydraulic braking system of a vehicle and vehicle

Abstract

The application discloses a kind of detection method of residual air in automobile hydraulic brake system and vehicle, detection method includes: setting test pressure value and first standard liquid quantity value;Control open valve route distribution module and close oil inlet valve, first infusion deviation value is obtained, whether there is air in valve route distribution module according to first infusion deviation value;Control open valve route distribution module and one of oil inlet valve, and control close other oil inlet valve, second infusion deviation value is obtained, whether there is air in brake caliper connected to the opened oil inlet valve according to second infusion deviation value;Whether there is air in brake caliper connected to the remaining oil inlet valve is detected repeatedly.The opening and closing of valve route distribution module and single oil inlet valve are controlled, valve route distribution module and four brake calipers are independently detected respectively, and then the position of air residue in the system is quickly and accurately positioned, the time cost and manpower cost are reduced, and the detection efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, in particular to a detection method for residual air in a hydraulic brake system of a vehicle. BACKGROUND

[0002] The hydraulic brake system on the market at present mainly adopts a "one box" brake-by-wire system (i.e. a brake-by-wire system with only one brake unit) with high integration, short braking time, convenient assembly and high energy recovery rate. The hydraulic brake system transmits the braking pressure of brake fluid to four brake calipers at the wheel end through a brake unit driven by a motor and a valve distribution module composed of multiple valves, to generate braking torque and vehicle deceleration, and then stop the vehicle. If there is air in the hydraulic brake system, the braking pressure transmitted to the brake caliper at the wheel end will be insufficient, which will result in insufficient braking torque and vehicle deceleration, and thus the vehicle will lose control and cannot be stopped, which will cause danger. In addition, if it is a non-decoupling brake system, the driver's foot feeling will also change, the brake pedal will be soft, the pedal stroke will be long, and the driver will feel uneasy. When the vehicle is assembled on the production line, the brake fluid will be filled through a vacuum filling device to ensure that the system has as little air as possible. When the brake parts are replaced and repaired at the 4S store, the hydraulic system will be exposed to air, which will cause air intake risk. If the operation is not proper during assembly or repair, air will be left in the hydraulic system, and the driving safety problem mentioned above will occur. Once the problem occurs, it needs to be repaired in the store, but the technician of the 4S store usually cannot quickly locate and troubleshoot the problem area where there is air in the hydraulic brake system, and can only re-evacuate the entire system, which is time-consuming and labor-intensive, and it is difficult to ensure that there is no air left in the system after a lot of work. SUMMARY

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a detection method for residual air in a hydraulic brake system of a vehicle, which can quickly and accurately locate the part where air is left in the system, reduce time and labor costs, and improve detection efficiency.

[0004] The detection method for residual air in a hydraulic brake system of a vehicle according to the first aspect of the present application, the hydraulic brake system comprises a valve distribution module, a brake pressure source module and four brake calipers, each brake caliper is connected with an oil inlet valve, the brake pressure source module controls the brake calipers to work or reset through the valve distribution module and the oil inlet valve, the brake pressure source module is connected with a displacement sensor, and the detection method comprises:

[0005] setting a test pressure value and a first standard required fluid volume value;

[0006] controlling to open the valve path distribution module and close the oil inlet valve, starting the brake pressure source module according to the test pressure value, obtaining first displacement data through the displacement sensor, calculating a first liquid delivery deviation value according to the first displacement data and the first standard liquid demand value, and judging whether there is air in the valve path distribution module according to the first liquid delivery deviation value;

[0007] If there is no air in the valve path distribution module, controlling to reset the valve path distribution module and the brake pressure source module.

[0008] controlling to open the valve path distribution module and one of the oil inlet valves and to close the other oil inlet valves, starting the brake pressure source module according to the test pressure value, obtaining second displacement data through the displacement sensor, calculating a second liquid delivery deviation value according to the second displacement data and the first displacement data, and judging whether there is air in the brake caliper connected to the opened oil inlet valve according to the second liquid delivery deviation value.

[0009] If there is no air in the brake caliper connected to the opened oil inlet valve, repeating the detection of whether there is air in the brake calipers connected to the remaining oil inlet valves until the detection of all four brake calipers is completed.

[0010] The method for detecting residual air in the automobile hydraulic brake system according to the first aspect of the present application has at least the following beneficial effects: by controlling the opening and closing of the valve path distribution module and the single oil inlet valve, different brake hydraulic pressure output conditions are created, the valve path distribution module and the four brake calipers are independently detected, and the position of the residual air in the system is quickly and accurately located, which facilitates the subsequent air check of the maintenance personnel, reduces the time cost and labor cost, and improves the detection efficiency.

[0011] According to some embodiments of the present application, the brake pressure source module includes a motor and a piston cylinder, the output end of the motor is in transmission connection with the piston of the piston cylinder, the output end of the piston cylinder is connected with the valve path distribution module, the displacement sensor is connected with the motor, and the first liquid delivery deviation value is calculated according to the first displacement data and the first standard liquid demand value, including: a first piston stroke value is obtained according to the first displacement data; a first actual liquid delivery value is calculated according to the piston diameter of the piston cylinder and the first piston stroke value; and the first liquid delivery deviation value is calculated according to the first actual liquid delivery value and the first standard liquid demand value.

[0012] According to some embodiments of the present application, the judging whether there is air in the valve path distribution module according to the first infusion deviation value comprises: setting a limit deviation value according to the test pressure value; comparing the first infusion deviation value with the limit deviation value; if the first infusion deviation value is greater than the limit deviation value, it is determined that there is air in the valve path distribution module, otherwise, it is determined that there is no air in the valve path distribution module.

[0013] According to some embodiments of the present application, after the determining that there is air in the valve path distribution module, the method further comprises: calculating the air volume in the valve path distribution module according to the first infusion deviation value and the test pressure value.

[0014] According to some embodiments of the present application, the calculating the air volume in the valve path distribution module according to the first infusion deviation value and the test pressure value comprises: calculating the air volume in the valve path distribution module by using the following formula: V1=P×(ΔV Z / (P-0.1)), wherein the first infusion deviation value is ΔV Z , the test pressure value is P, and the air volume in the valve path distribution module under the standard atmospheric pressure is V1.

[0015] According to some embodiments of the present application, before the controlling opening the valve path distribution module and one of the oil inlet valves, the method further comprises: selecting a wheel corresponding to the brake caliper connected with the oil inlet valve to be opened; and controlling rotating the wheel to form a gap between the wheel and the brake caliper for the brake caliper to move.

[0016] According to some embodiments of the present application, the calculating a second infusion deviation value according to the second displacement data and the first displacement data comprises: setting a second standard required liquid volume value; converting the first displacement data to obtain a first piston stroke value, and converting the second displacement data to obtain a second piston stroke value; calculating a second actual liquid volume value according to the first piston stroke value, the second piston stroke value and a piston diameter of the piston cylinder; and calculating the second infusion deviation value according to the second actual liquid volume value and the second standard required liquid volume value.

[0017] According to some embodiments of the present application, the detection method further comprises: if there is air in the brake caliper connected with the opened oil inlet valve, calculating an air volume in the brake caliper according to the second infusion deviation value and a test pressure value.

[0018] According to some embodiments of the present application, the brake pressure source module further comprises a master cylinder, the valve path distribution module comprises two first isolation valves connected with the master cylinder respectively, two second isolation valves connected with the piston cylinder respectively and a simulator valve connected with the master cylinder, the first isolation valves, the second isolation valves and the two oil inlet valves are correspondingly arranged, and the control of opening the valve path distribution module comprises: controlling the opening of the two first isolation valves and the two second isolation valves, and controlling the opening of the simulator valve.

[0019] According to some embodiments of the present application, the automobile hydraulic brake system further comprises an oil can, the oil can is connected with the master cylinder through a leak detection valve, and after the control of resetting the valve path distribution module and the brake pressure source module, the control comprises: controlling the closing of the leak detection valve.

[0020] The vehicle according to the second aspect of the embodiments of the present application comprises a memory, a processor and a program stored in the memory and executable on the processor, and when the program is executed by the processor, the steps of the method for detecting residual air in the automobile hydraulic brake system according to the first aspect of the present application are implemented.

[0021] The vehicle according to the second aspect of the embodiments of the present application has at least the following beneficial effects: different brake hydraulic pressure output conditions are created by controlling the opening and closing of the valve path distribution module and the single oil inlet valve, the valve path distribution module and the four brake calipers are independently detected respectively, the position of residual air in the system is quickly and accurately located, the subsequent air exhaust inspection of maintenance personnel is facilitated, the time cost and labor cost are reduced, and the detection efficiency is improved.

[0022] The computer readable storage medium according to the third aspect of the embodiments of the present application stores computer executable instructions, and the computer executable instructions are used to make the computer execute the steps of the method for detecting residual air in the automobile hydraulic brake system according to the first aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a step flow chart of the embodiment of the method for detecting residual air in the automobile hydraulic brake system of the present application;

[0024] Figure 2 is Figure 1 is a step flow chart of calculating the first infusion deviation value in the method;

[0025] Figure 3 is Figure 1 is a step flow chart of judging whether there is air in the valve path distribution module in the method;

[0026] Figure 4 is Figure 1The flow chart of the steps of controlling opening of the valve path distribution module and one of the oil inlet valves;

[0027] Figure 5 is Figure 1 The flow chart of the steps of calculating the second infusion deviation value. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application.

[0029] In the description of the present application, the meaning of one or more is one or more, the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0030] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0031] The method for detecting residual air in the hydraulic brake system of an automobile in one embodiment of the present application, the hydraulic brake system of the automobile includes an oil tank, a valve path distribution module, a brake pressure source module, and four brake calipers. Each brake caliper is respectively connected with an oil inlet valve (IV valve). The brake pressure source module controls the working or resetting of the brake calipers through the valve path distribution module and the oil inlet valve. The brake pressure source module is connected with a displacement sensor.

[0032] Specifically, the brake pressure source module includes a motor, a piston cylinder, and a master cylinder. The output end of the motor is drivingly connected with the piston of the piston cylinder through a rack and pinion structure. The displacement sensor is configured as an angular displacement sensor, and the angular displacement sensor is connected with the output end of the motor to detect the rotation angle of the motor. The master cylinder is connected with the brake pedal of the automobile and connected with the oil tank through a leak detection valve (TSV valve).

[0033] It should be noted that the leak detection valve is usually set as a normally open overflow valve. The leak detection valve can limit the pressure in the hydraulic brake system of the automobile to prevent system overload and damage. Installing the leak detection valve between the oil tank and the master cylinder can ensure that the system works below the rated pressure, thereby protecting the hydraulic elements from damage and being able to supplement brake oil to the master pump in time.

[0034] The valve path distribution module includes two normally open first isolation valves (CSV valves), two normally closed second isolation valves (PSV valves), and a normally closed simulator valve (SSV valve), the two first isolation valves are connected with the master cylinder respectively, the two second isolation valves are connected with the piston cylinder respectively, wherein the first isolation valve, the second isolation valve and the two oil inlet valves are connected correspondingly, the simulator valve is connected with the master cylinder, and the simulator valve is connected with a pedal simulator.

[0035] The automobile hydraulic brake system usually has two brake modes. In a normal case, the automobile hydraulic brake system is in a decoupling brake mode. When driving brake, the driver steps on the pedal, and a controller assembly (ECU) in the vehicle controls to close the two first isolation valves and controls to open the two second isolation valves and the simulator valve. The pedal transmits the driver's braking intention to the controller assembly through a pressure sensor, and the driver's pressure is input into the master cylinder after being amplified by the pedal. The brake oil in the master cylinder is transmitted to the pedal simulator through the simulator valve to simulate the parking brake pedal feeling and provide braking feedback to the driver.

[0036] The controller assembly signals the driver's intention through the internal stroke sensor and pressure sensor according to the rate and stroke of the driver stepping on the pedal. After internal operation, the controller assembly controls the operating speed of the motor in the brake pressure source adjustment module, converts the rotary motion of the motor into the linear motion of the piston through the rack and pinion structure, drives the piston to advance, and the piston cylinder delivers brake oil to the oil inlet valve through the second isolation valve and generates brake pressure. The brake pressure is transmitted to the brake caliper circuit through the oil inlet valve, thereby generating brake force to brake the wheels. Obviously, the actual vehicle deceleration of the decoupling brake is controlled by the controller assembly detecting the pedal displacement, controlling the motor speed, and then controlling the piston cylinder output pressure to control the vehicle braking force.

[0037] When any one or more of the motor, piston cylinder, second isolation valve and simulator valve fails, the decoupling brake is difficult to operate normally, and the automobile hydraulic brake system automatically switches to a backup brake mode. When driving brake, the driver steps on the pedal, and the controller assembly controls to open the two first isolation valves and controls to close the two second isolation valves and the simulator valve. The driver's foot force is input into the master cylinder after being amplified by the pedal; the pressure generated in the input master cylinder is directly transmitted to the oil inlet valve through the first isolation valve, and then further transmitted to the brake caliper circuit, thereby generating brake force to brake the wheels.

[0038] Referring to Figure 1 The method for detecting residual air in the automobile hydraulic brake system includes:

[0039] In step S100, a test pressure value P and a first standard liquid demand value V0 are set.

[0040] Step S200, control to open the valve path distribution module and close the oil inlet valve, start the brake pressure source module according to the test pressure value P, obtain the first displacement data through the displacement sensor, and calculate the first infusion deviation value ΔV according to the first displacement data and the first standard liquid demand value V0 Z , whether there is air in the valve path distribution module according to the first infusion deviation value ΔV Z

[0041] Step S300, if there is no air in the valve path distribution module, control the valve path distribution module and the brake pressure source module to reset;

[0042] Step S400, control to open the valve path distribution module and one of the oil inlet valves, and control to close the other oil inlet valves, start the brake pressure source module according to the test pressure value P, obtain the second displacement data through the displacement sensor, calculate the second infusion deviation value according to the second displacement data and the first displacement data, and determine whether there is air in the brake caliper connected to the opened oil inlet valve according to the second infusion deviation value;

[0043] Step S500, if there is no air in the brake caliper connected to the opened oil inlet valve, repeat the detection of whether there is air in the brake calipers connected to the remaining oil inlet valves until all four brake calipers are detected.

[0044] It should be noted that before the vehicle is detected, the tire needs to be lifted off the ground by a lifting machine; then prepare the after-sales diagnostic instrument, design the after-sales diagnostic instrument diagnosis ID, and send relevant instructions to the controller assembly through the diagnostic instrument diagnosis ID, which is convenient for subsequent maintenance personnel to control the opening or closing of the leak detection valve, valve path distribution module and oil inlet valve, and control the motor to build pressure.

[0045] It can be understood that in step S200, the step of controlling to open the valve path distribution module and close the oil inlet valve includes:

[0046] Control to open two first isolation valves and two second isolation valves, and control to open the simulator valve.

[0047] It can be understood that during testing, the maintenance personnel will not actually step on the pedal to control the brake caliper brake through the decoupling brake mode or backup brake mode, but can set the detection pressure using the after-sales diagnostic instrument before opening the valve path distribution module. After the controller assembly receives the signal of setting the test pressure sent by the after-sales diagnostic instrument, the test pressure value P is automatically set and the first standard liquid demand value V0 is set according to the test pressure value P. Then the controller assembly controls to open the valve path distribution module and close the oil inlet valves connected to the four brake calipers, and at the same time, the motor of the brake pressure source module is started according to the test pressure value P. At this time, the simulator valve between the master pump and the simulator, the first isolation valve between the master pump and the oil inlet valve, and the second isolation valve between the piston pump and the oil inlet valve are all opened.​

[0048] After the motor starts, it drives the piston of the piston pump through the rack and worm gear structure. The displacement sensor acquires the first displacement data and sends it to the controller assembly. The controller assembly can calculate the first infusion deviation value ΔV based on the first displacement data and the first standard liquid demand value V0. Z First infusion deviation value ΔV Z That is, the braking force output by the piston pump reaches the first actual liquid output value V when the test pressure value P is reached. Z The controller assembly can determine the difference between the theoretically required fluid volume V0 and the first standard fluid delivery deviation value ΔV when the braking force output by the piston pump reaches the test pressure value P. Z Determine if there is air inside the valve distribution module.

[0049] It is understandable that in step S300, the control valve distribution module and the brake pressure source module are reset, that is, the simulator valve, the four oil inlet valves, and the first isolation valve, the two second isolation valves, the simulator valve, etc. in the valve distribution module are restored to their normal open or normally closed states, and the motor and piston cylinder are reset to their initial non-moving state. The specific opening and closing states of each valve can be referred to the previous description, and will not be repeated here.

[0050] By resetting the control valve distribution module and the brake pressure source module, the automotive hydraulic braking system can simulate real driving conditions, improving the realism of the test and avoiding cumulative errors caused by the failure of the control valve distribution module and the brake pressure source module to be reset in multiple testing steps.

[0051] It is understandable that after step S300, the following steps are included:

[0052] The controller assembly controls the shut-off of the leak detection valve.

[0053] In addition to resetting the valve distribution module and the brake pressure source module, step S300 also resets the leak detection valve to the normally open state. Therefore, after controlling the valve distribution module and the brake pressure source module to reset, and before controlling the opening of the valve distribution module and one of the oil inlet valves, the controller assembly will also control the closing of the leak detection valve to prevent the normally open leak detection valve from affecting the sealing of the valve distribution module during subsequent testing, thereby affecting the test results and ensuring the completeness of the testing steps.

[0054] By controlling the opening and closing of the valve distribution module and a single inlet valve, different brake fluid pressure output conditions are created. The valve distribution module and the four brake calipers are then tested independently in sequence, thereby quickly and accurately locating the location of residual air in the system. This allows for accurate and rapid determination of whether air exists in the valve distribution module, a single brake caliper, or multiple brake calipers, facilitating subsequent air bleed inspections by maintenance personnel, reducing time and labor costs, and improving testing efficiency.

[0055] Specifically, referring to Figure 2 It can be understood that in step S200, the first infusion deviation value ΔV Z is calculated according to the first displacement data and the first standard required liquid volume value V0

[0056] Step S210, the first piston stroke value L0

[0057] Step S220, the first actual liquid volume value V Z is calculated according to the piston diameter of the piston cylinder and the first piston stroke value L0

[0058] Step S230, the first infusion deviation value ΔV Z is calculated according to the first actual liquid volume value V Z and the first standard required liquid volume value V0

[0059] Wherein, the first displacement data obtained by the displacement sensor, that is, the first rotation angle of the output shaft of the motor detected by the angular displacement sensor when the motor is working, the first rotation angle and the fixed parameters such as pitch and transmission ratio of the rack and pinion structure are simply calculated, and the first rotation angle can be converted into the first piston stroke value L0

[0060] The piston advances to push the brake oil in the piston cylinder into the valve path distribution module, and the first actual liquid volume value V Z is obtained by multiplying the piston diameter of the piston cylinder and the first piston stroke value L0

[0061] The difference between the first actual liquid volume value V Z and the first standard required liquid volume value V0 Z , the first infusion deviation value ΔV Z is obtained, that is, the difference between the actual required brake oil volume and the theoretical required brake oil volume when the pressure of the brake oil in the valve path distribution module reaches the test pressure value P.

[0062] When there is air in the valve path distribution module, compared with the case where there is no air in the valve path distribution module, the pressure in the valve path distribution module with air will decrease when the piston cylinder outputs the same amount of brake oil, and the motor needs to continue to run to make the piston of the piston cylinder continue to travel a certain distance, and a certain amount of brake oil is supplemented, so as to reach the pressure generated by the brake oil in the valve path distribution module without air.

[0063] By converting the first piston stroke value L0 ZThe method can help maintenance personnel to quickly and accurately determine whether there is air in the valve path distribution module, facilitate subsequent calculation of the air volume, and effectively improve the accuracy of the detection result.

[0064] Referring to Figure 3 Fig. 2, it can be understood that in step S200, according to the first infusion deviation value ΔV Z The step of determining whether there is air in the valve path distribution module includes:

[0065] In step S240, a limit deviation value ΔV M is set according to the test pressure value P.

[0066] In step S250, the first infusion deviation value ΔV Z and the limit deviation value ΔV M are compared.

[0067] In step S260, if the first infusion deviation value ΔV Z is greater than the limit deviation value ΔV M , it is determined that there is air in the valve path distribution module, otherwise, it is determined that there is no air in the valve path distribution module.

[0068] Specifically, considering the influence of brake oil loss, environmental temperature, atmospheric pressure, detection error and other factors, the actual liquid output of the piston cylinder reaching the test pressure value P is usually not equal to the theoretical liquid demand, that is, there is a certain system deviation between the first actual liquid output value V Z and the first standard liquid demand value V0. Under the premise of reasonable detection environment standard and detection step, the maximum value allowed by the system deviation is the limit deviation value ΔV M .

[0069] It should be noted that the limit deviation value ΔV M usually corresponds to the test pressure value P. The user can set the corresponding limit deviation value ΔV M after setting the test pressure value P according to experience, or can input the test pressure value P and the limit deviation value ΔV M corresponding table in advance in the after-sales diagnostic instrument, but after the user sets the test pressure value P, the after-sales diagnostic instrument can automatically set the limit deviation value ΔV M according to the corresponding table.

[0070] When the controller assembly determines whether there is air in the valve path distribution system, the limit deviation value ΔV M is used as the reference for whether there is air, and when the error between the first actual liquid output value V Z and the first standard liquid demand value V0 (i.e., the first infusion deviation value ΔV Z ) is greater than the limit deviation value ΔV M, i.e. excluding the interference of brake oil loss, ambient temperature, atmospheric pressure, detection error and other factors, the first actual liquid output value V Z is still much larger than the first standard liquid demand value V0 actually required by the valve path distribution system, it is determined that there is air in the valve path distribution system; on the contrary, when the error between the first actual liquid output value V Z and the first standard liquid demand value V0 is less than or equal to the limit deviation value ΔV M , it indicates that the first actual liquid output value is within the normal error range, and it can be determined that there is no air or a small amount of air that does not affect normal use in the valve path distribution system.

[0071] By setting the limit deviation value ΔV M , the detection result can be prevented from being interfered by brake oil loss, ambient temperature, atmospheric pressure, detection error and other factors, and the accuracy of the detection result is further improved.

[0072] Referring to FIG. 1, Figure 1 it can be understood that after it is determined that there is air in the valve path distribution system, it further includes:

[0073] The air volume V1 in the valve path distribution system is calculated according to the first liquid delivery deviation value ΔV Z calculated and the preset test pressure value P, so as to facilitate subsequent problem troubleshooting or air exhausting operation.

[0074] Specifically, the air in the valve path distribution system can be approximately regarded as an ideal gas, so as to calculate the air volume V1 in the valve path distribution module by using the ideal gas state equation. According to the ideal gas state equation PV = nRT, wherein n is the amount of substance (unit: mol) of the gas, R is the molar gas constant (unit: J / (mol·K)), and T is the temperature (unit: K). It can be known that the air satisfies 0.1×V1 = nRT at the standard atmospheric pressure, and the air satisfies P×(V1-△V z ) = nRT in the valve path distribution module, and △Vz is the first actual liquid output value V Z In order to supplement the brake oil content required by the pressure, (V1-△V z ) is the air volume compressed in the valve path distribution module after the valve path distribution system reaches the test pressure by supplementing the brake oil. Obviously, 0.1×V1 = P×(V1-△V z ), and the formula is changed to obtain V1 = P×(ΔV Z / (P-0.1)), the first liquid delivery deviation value ΔV Z and the test pressure value P are substituted, and the air volume V1 in the valve path distribution system can be calculated.

[0075] By accurately calculating the air volume V1 in the valve path distribution system, the maintenance personnel can perform data analysis and accurately perform the exhaust operation. In addition, when the maintenance personnel excludes the air in the valve path distribution system, the detection will not stop, but continue to perform subsequent steps S300, steps S400, steps S500, etc., to ensure comprehensive and accurate detection of each module in the automobile hydraulic brake system.

[0076] Referring to Figure 4 It can be understood that, in step S400, before the step of controlling the opening of the valve path distribution module and one of the oil inlet valves, the method further comprises:

[0077] Step S410, selecting a wheel corresponding to the brake caliper connected to the oil inlet valve to be opened;

[0078] Step S420, controlling the rotation of the wheel to form a gap between the wheel and the brake caliper for the movement of the brake caliper.

[0079] The brake caliper mainly converts the pressure of the brake oil into mechanical force to clamp the brake disc, thereby achieving the braking of the vehicle. Before opening one of the oil inlet valves, the wheel corresponding to the brake caliper connected to the oil inlet valve to be opened is fully rotated, so that the brake caliper corresponding to the oil inlet valve is separated from the wheel, and a gap is formed between the wheel and the brake caliper for the movement of the brake caliper, thereby avoiding the problem that when the valve path distribution module transmits pressure to the brake caliper, the brake caliper disperses stress due to the obstruction of the wheel, resulting in a second liquid deviation value and other problems, and improving the accuracy of the detection result of whether the brake caliper contains air.

[0080] Referring to Figure 5 It can be understood that, in step S400, the step of calculating the second liquid deviation value according to the second displacement data and the first displacement data comprises:

[0081] Step S430, setting a second standard liquid demand value;

[0082] Step S440, converting the first displacement data to obtain a first piston stroke value L0, and converting the second displacement data to obtain a second piston stroke value L1;

[0083] Step S450, calculating a second actual liquid output value according to the first piston stroke value L0, the second piston stroke value L1, and the piston diameter of the piston cylinder;

[0084] Step S460, calculating a second liquid deviation value according to the second actual liquid output value and the second standard liquid demand value.

[0085] Step S400 is to detect whether there is air in the single brake caliper, therefore, compared with step S200, step S400 opens an oil inlet valve connected with the brake caliper to be detected, at this time, the piston pump needs to transmit a certain amount of brake oil to the opened oil inlet valve to ensure that the pressure delivered by the oil inlet valve to the brake caliper reaches the test pressure value P, in other words, compared with step S200, the oil outlet amount of the piston cylinder increases, and the theoretically increased oil outlet amount of the piston cylinder is the second standard liquid demand value, and the actually increased oil outlet amount of the piston cylinder is the second actual liquid amount value.

[0086] The increase of the oil outlet amount of the piston cylinder, i.e. the increase of the rotation angle of the motor and the stroke of the piston, the angular displacement sensor detects the second rotation angle of the output shaft of the motor when the motor is working, and the second rotation angle and the fixed parameters such as the pitch of the rack and pinion structure and the transmission ratio are simply calculated to convert the second rotation angle into the second piston stroke value L1 of the piston. The difference between the second piston stroke value L1 and the first piston stroke value L0 is multiplied by the piston diameter of the piston cylinder to obtain the second actual liquid amount value required for the brake caliper corresponding to the left front wheel to reach the test pressure value P.

[0087] The difference between the second actual liquid amount value and the second standard liquid demand value is the second liquid delivery deviation value, which is the difference between the actual required brake oil amount and the theoretically required brake oil amount when the brake oil pressure in the brake caliper corresponding to the left front wheel reaches the test pressure value P (excluding the brake oil in the valve distribution system). For example, opening the oil inlet valve connected with the brake caliper corresponding to the left front wheel, the difference between the actual required brake oil amount and the theoretically required brake oil amount of the piston cylinder is the second liquid delivery deviation value of the left front end (FL end), denoted as ΔV FL (the second liquid delivery deviation value of the right front end brake caliper reaching the test pressure is ΔV FR , the second liquid delivery deviation value of the right rear end brake caliper reaching the test pressure is ΔV RR , and the second liquid delivery deviation value of the left rear end brake caliper reaching the test pressure is ΔV RL ), hereinafter, the brake caliper corresponding to the left front wheel and the oil inlet valve are taken as examples for description, and it is particularly pointed out that the following will not be described again.

[0088] By converting the second piston stroke value L1 actually traveled by the piston, and further calculating the second liquid delivery deviation value ΔV FL , the maintenance personnel can quickly and accurately judge whether there is air in the brake caliper, and at the same time, it is convenient for subsequent calculation of the air volume, and effectively improves the accuracy of the detection result.

[0089] It can be understood that since the test pressure value P of the brake caliper and the valve distribution system is equal, the brake caliper can also be compared with the second liquid delivery deviation value and the limit deviation value ΔVM The size of the air in the brake caliper.

[0090] Specifically, the controller assembly determines whether air is present in the brake caliper when the second actual liquid output value is greater than the second standard liquid requirement value by a limit deviation value ΔV M As a reference for the presence of air, when the error between the second actual liquid output value and the second standard liquid requirement value (i.e., the second infusion deviation value ΔV FL ) is greater than the limit deviation value ΔV M , i.e., excluding the influence of brake oil loss, environmental temperature, atmospheric pressure, detection error, etc., the second actual liquid output value is still much greater than the second standard liquid requirement value actually required by the brake caliper, and it is determined that air is present in the brake caliper; conversely, when the error between the second actual liquid output value and the second standard liquid requirement value is less than or equal to the limit deviation value ΔV M , it means that the second actual liquid output value is within a normal error range, and it can be determined that there is no air or a small amount of air that does not affect normal use in the brake caliper.

[0091] It can be understood that in step S500, when it is determined that no air is present in the detected brake caliper, the controller assembly repeats steps S300 and S400, i.e., the valve path distribution module and the brake pressure source module are reset, and the closing of the leak detection valve, the opening of the valve path distribution module, and one of the oil inlet valves that has not been detected are controlled again until all four brake calipers are detected.

[0092] Referring to FIG. 7, it can be understood that when it is determined that air is present in the detected brake caliper, it further includes: Figure 1

[0093] According to the calculated second infusion deviation value ΔV FL and the preset test pressure value P, the air volume V2 in the brake caliper is calculated. Thus, subsequent problem troubleshooting or air exhaust operations are facilitated.

[0094] Specifically, the air in the brake caliper can be approximated as an ideal gas, and thus the air volume V2 in the valve path distribution module is calculated using the ideal gas state equation. The specific principles and calculation process are described above with respect to the calculation process of the air volume V1 in the valve path module, and thus will not be described again.

[0095] Obviously, 0.1×V2=P×(V2-△V FL ), and V2=P×(ΔV FL / (P-0.1)) can be obtained by changing the above formula. The second infusion deviation value and the test pressure value P are substituted to calculate the air volume V2 in the brake caliper.

[0096] ​By accurately calculating the air volume V2 in the brake caliper, the maintenance personnel can help analyze the data and accurately perform the exhaust operation. In addition, when the maintenance personnel exhausts the air in the brake caliper, the detection will not stop, but will continue to repeatedly perform subsequent steps S300, steps S400, steps S500, etc., to ensure comprehensive and accurate detection of each module in the automobile hydraulic brake system.

[0097] Some embodiments of the present application propose a vehicle comprising a processor, a memory, and a computer program stored on the memory and capable of running on the processor, which, when executed by the processor, implements each process of the above-mentioned embodiment of the method for detecting residual air in an automobile hydraulic brake system and achieves the same technical effects. To avoid repetition, this will not be repeated here.

[0098] Some embodiments of the present application propose a computer-readable storage medium comprising: a computer program stored on the computer-readable storage medium, which, when executed by the processor, implements each process of the above-mentioned embodiment of the method for detecting residual air in an automobile hydraulic brake system and achieves the same technical effects. To avoid repetition, this will not be repeated here.

[0099] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0100] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, device, or computer program product. Therefore, the embodiments of the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0101] The embodiments of the present application are described with reference to flowcharts and / or block diagrams according to the method, terminal device (system), and computer program product of the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to produce a machine, so that the instructions executed by the computer or other programmable data processing terminal device produce a device that implements the functions specified in the flowchart and / or block diagram. Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks

[0102] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow Figure 1 flow or flows and / or blocks Figure 1 of the flow or flows and / or blocks.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 flow or flows and / or blocks ​ of the flow or flows and / or blocks.

[0104] Although preferred embodiments of the present application have been described, those skilled in the art will be able to make additional modifications and variations to the described embodiments without departing from the inventive concepts disclosed in the application. Accordingly, the appended claims are intended to cover all such modifications and variations as falling within the scope of the present application.

[0105] Finally, it should be noted that the terms "first", "second", and the like, herein do not necessarily denote any ordinal, chronological or other relationship, and are merely used to distinguish one entity or action from another but do not necessarily denote any such actual relationship or order. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0106] The above embodiments of the present application have been described in detail, finally it should be noted that: the above embodiments are only used to explain the technical solutions of the present application, not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting residual air in a hydraulic brake system of a vehicle, the hydraulic brake system comprising a valve path distribution module, a brake pressure source module and four brake calipers, each of the brake calipers being connected with an oil inlet valve, the brake pressure source module controlling the brake calipers to work or reset through the valve path distribution module and the oil inlet valve, the brake pressure source module being connected with a displacement sensor, characterized in that, The method comprises: setting a test pressure value and a first standard liquid demand value; controlling to open the valve path distribution module and close the oil inlet valve, starting the brake pressure source module according to the test pressure value, and obtaining first displacement data through the displacement sensor, then calculating a first liquid delivery deviation value according to the first displacement data and the first standard liquid demand value, and judging whether there is air in the valve path distribution module according to the first liquid delivery deviation value; if there is no air in the valve path distribution module, controlling to reset the valve path distribution module and the brake pressure source module; controlling to open the valve path distribution module and one of the oil inlet valves, and controlling to close the other oil inlet valves, starting the brake pressure source module according to the test pressure value, and obtaining second displacement data through the displacement sensor, then calculating a second liquid delivery deviation value according to the second displacement data and the first displacement data, and judging whether there is air in the brake caliper connected with the opened oil inlet valve according to the second liquid delivery deviation value; if there is no air in the brake caliper connected with the opened oil inlet valve, repeating the detection of whether there is air in the brake calipers connected with the remaining oil inlet valves until the detection of all four brake calipers is completed.

2. The method of claim 1, wherein the brake pressure source module comprises a motor and a piston cylinder, an output of the motor is drivingly connected to a piston of the piston cylinder, an output of the piston cylinder is connected to the valve path distribution module, and the displacement sensor is connected to the motor. The method comprises: calculating a first piston stroke value according to the first displacement data; calculating a first actual liquid delivery value according to the piston diameter of the piston cylinder and the first piston stroke value; calculating the first liquid delivery deviation value according to the first actual liquid delivery value and the first standard liquid demand value.

3. The method of detecting residual air in an automotive hydraulic brake system according to claim 2, wherein The method comprises: setting a limit deviation value according to the test pressure value; comparing the first liquid delivery deviation value with the limit deviation value; if the first liquid delivery deviation value is greater than the limit deviation value, it is determined that there is air in the valve path distribution module, otherwise, it is determined that there is no air in the valve path distribution module.

4. The method of detecting residual air in an automotive hydraulic brake system according to claim 3, characterized by, After it is determined that there is air in the valve path distribution module, the method comprises: calculating the air volume in the valve path distribution module according to the first liquid delivery deviation value and the test pressure value.

5. The method of detecting residual air in an automotive hydraulic brake system according to claim 4, wherein The method comprises: calculating the air volume in the valve path distribution module by using the following formula: V1 = P x (ΔV Z / (P - 0.1)), wherein the first infusion deviation value is ΔV Z , the test pressure value is P, and the air volume in the valve path distribution module under standard atmospheric pressure is V1.

6. The method of detecting residual air in an automotive hydraulic brake system according to claim 2, wherein Before the control to open the valve path distribution module and one of the oil inlet valves, the method comprises: selecting a wheel corresponding to the brake caliper connected with the oil inlet valve to be opened; controlling to rotate the wheel to form a gap between the wheel and the brake caliper for the movement of the brake caliper.

7. The method of detecting residual air in an automotive hydraulic brake system according to claim 2 or 6, characterized in that, The method comprises: setting a second standard liquid demand value; calculating a first piston stroke value according to the first displacement data, and calculating a second piston stroke value according to the second displacement data; calculating a second actual liquid delivery value according to the first piston stroke value, the second piston stroke value and a piston diameter of the piston cylinder; calculating the second infusion deviation value according to the second actual liquid delivery value and the second standard liquid demand value.

8. The method of detecting residual air in an automotive hydraulic brake system according to claim 7, wherein The detection method further comprises: if there is air in the brake caliper connected with the opened oil inlet valve, calculating an air volume in the brake caliper according to the second infusion deviation value and a test pressure value.

9. The method of claim 2, wherein the brake pressure source module further comprises a master cylinder, the valve path distribution module comprises two first isolation valves connected to the master cylinder respectively, two second isolation valves connected to the piston cylinder respectively, and an emulator valve connected to the master cylinder, and the first isolation valves, the second isolation valves and the two inlet valves are correspondingly arranged. The control of opening the valve path distribution module comprises: controlling to open two first isolation valves and two second isolation valves, and controlling to open the simulator valve.

10. The method of claim 9, wherein the hydraulic brake system of an automobile further comprises an oil reservoir connected to the master cylinder through a leak detection valve, and wherein The control of resetting the valve path distribution module and the brake pressure source module comprises: controlling to close the leak detection valve.

11. A vehicle characterized by comprising: The program is stored in the memory and executable on the processor, and when the program is executed by the processor, the steps of the detection method of residual air in the automotive hydraulic brake system according to any one of claims 1 to 10 are implemented.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer executable instructions for causing a computer to execute the steps of the detection method of residual air in the automotive hydraulic brake system according to any one of claims 1 to 10.

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