Gas detection method and device based on Onebox hydraulic braking system

Abstract

The invention provides a gas detection method and device based on an Onebox hydraulic brake system, and relates to the technical field of brake system detection. The method comprises the steps that in response to the fact that a target vehicle meets gas detection conditions, pressure building is conducted on an electric cylinder after exhaust is conducted on an electric cylinder loop, and a detection deviation value is obtained; after the electric cylinder loop is supplemented with liquid, the electric cylinder is subjected to pressure building, and the initial gas content is obtained; and determining the gas content of the electric cylinder loop according to the detection deviation value and the initial gas content. Based on the error of the indirect detection method, the piston is pushed to discharge the brake fluid gas out of the detection loop, the detection deviation value is calculated, then the gas content of the brake system is detected, the accuracy and reliability of gas content detection can be improved, and the vehicle safety can be improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of brake system detection, and particularly relates to a gas detection method and device based on a Onebox hydraulic brake system. BACKGROUND

[0002] In an automotive hydraulic brake system, air intrusion or gas generated by high temperature of brake fluid can increase brake pedal travel and weaken vehicle braking force, which poses a potential safety hazard to the vehicle. The gas detection method in the related art has certain limitations on vehicle detection conditions, and does not consider the error of the detection method, which can result in inaccurate detection of gas content.

[0003] In an automotive hydraulic brake system, air intrusion or gas generated by high temperature of brake fluid can significantly increase brake pedal travel and weaken braking force, which poses a serious safety hazard. The gas detection method in the related art relies on indirect measurement means to calculate the gas content by other parameters of the brake system. This indirect detection method has errors in the detection method itself, resulting in problems of insufficient accuracy and low reliability in detecting the gas content. SUMMARY

[0004] The present disclosure aims to at least partially solve one of the technical problems in the related art.

[0005] To this end, a first aspect of the present disclosure provides a gas detection method based on a Onebox hydraulic brake system. An electric cylinder unit in the Onebox hydraulic brake system is connected to a liquid inlet valve and a liquid return valve of a wheel through an electric cylinder isolation valve. The electric cylinder unit includes an electric cylinder, a motor, and a piston. A pressure increasing electromagnetic valve and a pressure reducing electromagnetic valve are arranged on the liquid inlet valve and the liquid return valve, respectively. The method includes the following steps: In response to a target vehicle meeting a gas detection condition, the electric cylinder circuit is exhausted. The electric cylinder circuit is a passage between the electric cylinder and the electric cylinder isolation valve. The electric cylinder is built up to a preset pressure for a first time. A first actual brake fluid volume pushed by the piston in the first time and a first calibration brake fluid volume are determined. A difference between the first actual brake fluid volume and the first calibration brake fluid volume is taken as a detection deviation value. The electric cylinder is supplemented with liquid. After the liquid is supplemented, the electric cylinder is built up to the preset pressure for a second time. A second actual brake fluid volume pushed by the piston in the second time and a second calibration brake fluid volume are determined. A difference between the second actual brake fluid volume and the second calibration brake fluid volume is taken as an initial gas content of the electric cylinder circuit. determining the gas content of the electric cylinder circuit according to the initial gas content and the detected deviation value.

[0006] In some embodiments of the present disclosure, the first actual brake fluid volume pushed by the piston in the first pressure building process is determined by: determining a first initial position of the piston; pushing the piston and stopping pushing when the pressure of the electric cylinder reaches the preset pressure, and determining a first stop position of the piston; determining the first actual brake fluid volume pushed by the piston according to the piston stroke difference between the first initial position and the first stop position and the piston area; and determining the first calibration brake fluid volume pushed by the piston according to the preset pressure and a preset P-V curve, the P-V curve being used to describe the mapping relationship between the cylinder pressure and the brake fluid volume.

[0007] In some embodiments of the present disclosure, the preset pressure is determined by: determining a minimum brake fluid discharge amount capable of discharging the gas in the electric cylinder circuit; determining a remaining brake fluid amount of the electric cylinder based on the minimum brake fluid discharge amount; determining a maximum pressure building pressure value of the remaining brake fluid amount; determining a minimum pressure value in a linear region of the P-V curve; and determining the preset pressure within the interval range of the maximum pressure building pressure value and the minimum pressure value.

[0008] In some embodiments of the present disclosure, the preset pressure is determined within the interval range of the maximum pressure building pressure value and the minimum pressure value by: taking the median value of the maximum pressure building pressure value and the minimum pressure value as the preset pressure.

[0009] In some embodiments of the present disclosure, the gas detection condition includes that the target vehicle is in a vehicle power-on self-checking state or a stable driving state; wherein the vehicle power-on self-checking state includes ignition cycle starting and no braking, and the vehicle is stationary; and the stable driving state includes that the speed of the target vehicle is within a preset threshold interval, and the speed variation rate is less than a preset variation threshold, and the pressure increasing electromagnetic valve and the pressure reducing electromagnetic valve are in a closed state.

[0010] In some embodiments of the present disclosure, the method further includes: comparing the gas content with a set gas content over-standard threshold value; and when the gas content is greater than or equal to the gas content over-standard threshold value, determining that the gas content of the Onebox hydraulic brake system is over-standard, and generating a gas content over-standard alarm information.

[0011] In some embodiments of the present disclosure, the method further includes: after determining the gas content of the electric cylinder circuit, controlling the electric cylinder to be depressurized and the piston to be returned.

[0012] The second aspect of the present disclosure provides a gas detection device based on a Onebox hydraulic braking system, wherein an electric cylinder unit in the Onebox hydraulic braking system is connected with a liquid storage tank and a wheel liquid inlet and return valve path through an electric cylinder isolation valve, the electric cylinder unit comprises an electric cylinder, a motor and a piston, and a pressure increasing electromagnetic valve and a pressure reducing electromagnetic valve are arranged on the liquid inlet and return valve path respectively; the device comprises: An exhaust module is configured to exhaust the electric cylinder circuit in response to a target vehicle meeting a gas detection condition, wherein the electric cylinder circuit is a passage between the electric cylinder and the electric cylinder isolation valve; A first pressure building module is configured to build pressure for the electric cylinder for the first time according to a preset pressure, to determine a first actual brake liquid volume pushed by the piston in the first pressure building process and a first calibrated brake liquid volume, and to take a difference between the first actual brake liquid volume and the first calibrated brake liquid volume as a detection deviation value; A liquid supplementing module is configured to supplement liquid for the electric cylinder; A second pressure building module is configured to build pressure for the electric cylinder for the second time according to the preset pressure after the liquid supplementing, to determine a second actual brake liquid volume pushed by the piston in the second pressure building process and a second calibrated brake liquid volume, and to take a difference between the second actual brake liquid volume and the second calibrated brake liquid volume as an initial gas content of the electric cylinder circuit; A detection module is configured to determine a gas content of the electric cylinder circuit according to the initial gas content and the detection deviation value.

[0013] The third aspect of the present disclosure provides an electronic device, comprising a processor and a memory connected with the processor in communication; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the method of the first aspect.

[0014] The fourth aspect of the present disclosure provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by a processor to implement the method of the first aspect.

[0015] The gas detection method based on the Onebox hydraulic braking system provided by the present disclosure considers the error of the indirect detection method itself, expels brake liquid gas from the detection circuit by pushing the piston, calculates the detection deviation value, and then detects the gas content of the braking system, which can improve the accuracy and reliability of the detection of the gas content and improve the safety of the vehicle.

[0016] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 A schematic flowchart of a gas detection method based on a Onebox hydraulic braking system provided in this embodiment of the present disclosure; Figure 2 A schematic diagram of a Onebox hydraulic braking system provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of a gas detection device based on a Onebox hydraulic braking system, provided as an embodiment of the present disclosure. Detailed Implementation

[0018] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0019] Specifically, the following describes a gas detection method and apparatus based on the Onebox hydraulic braking system according to embodiments of the present disclosure with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic flowchart illustrating a gas detection method based on a Onebox hydraulic braking system, provided in an embodiment of this disclosure. Figure 2 This is a schematic diagram of a Onebox hydraulic braking system provided in an embodiment of this disclosure.

[0021] like Figure 2 As shown, in some embodiments of this disclosure, the Onebox hydraulic braking system may include an electric cylinder unit 201, an electric cylinder isolation valve PSV 202, a reservoir 203, and inlet and return valve lines 204 for the wheels. The electric cylinder unit 201 includes an electric cylinder 205, a motor 206, and a piston 207. The inlet and return valve lines 204 are respectively equipped with a pressure boosting solenoid valve ISO 208 and a pressure reducing solenoid valve Dump 209. The electric cylinder unit 201 is connected to the reservoir 203 and the inlet and return valve lines 204 through the electric cylinder isolation valve PSV 202. Figure 2 Other components include: brake pedal 210, test valve TSV211, manual cylinder isolation valve CSV212, and simulation valve SSV.

[0022] like Figure 1As shown, the gas detection method based on the Onebox hydraulic braking system provided by the embodiments of the present disclosure can include the following steps: Step 101, in response to the target vehicle satisfying the gas detection condition, the electric cylinder circuit is vented.

[0023] The electric cylinder circuit is the passage between the electric cylinder and the electric cylinder isolation valve.

[0024] In some embodiments of the present disclosure, the gas detection condition can include that the target vehicle is in a vehicle power-on self-checking state or a stable driving state.

[0025] The vehicle power-on self-checking state includes starting the ignition cycle and no braking, and the vehicle is stationary. The stable driving state includes that the speed of the target vehicle is in a preset threshold interval, and the vehicle speed change rate is less than a preset change threshold, and the pressure increasing electromagnetic valve and the pressure reducing electromagnetic valve are in a closed state. That is, the stable driving state limits the vehicle speed and the vehicle speed change, avoiding the risk of insufficient braking force caused by stepping on the brake to build pressure due to the interruption of the current detection delay. When it is determined that the target vehicle is in a driving state, all pressure increasing electromagnetic valves and pressure reducing electromagnetic valves on the inlet and return valve paths need to be closed. That is, the gas detection method provided by the embodiments of the present disclosure can be detected not only in the stationary state of the vehicle, but also in the driving process of the vehicle, expanding the application scenario range of gas detection.

[0026] Venting the electric cylinder circuit can include: S1, opening the electric cylinder isolation valve PSV202; S2, pushing the piston forward to build pressure, and pushing the brake fluid to the test valve TSV211, the manual cylinder isolation valve CSV212, and the electric cylinder isolation valve PSV202 circuit, to vent the brake fluid gas originally in the electric cylinder circuit until the piston stops at a preset stroke; S3, closing the electric cylinder isolation valve PSV202, and retaining a small amount of brake fluid in the electric cylinder circuit.

[0027] Step 102, building pressure in the electric cylinder according to a preset pressure for the first time, determining a first actual brake fluid volume pushed by the piston in the first time building pressure process and a first calibrated brake fluid volume, and taking the difference between the first actual brake fluid volume and the first calibrated brake fluid volume as a detection deviation value.

[0028] In an implementation, in the first pressure building process, a first initial position of the piston can be determined; the piston is pushed, and when the pressure of the electric cylinder reaches a preset pressure, the pushing is stopped, a first stop position of the piston is determined; a first actual brake liquid volume pushed by the piston is determined according to a piston stroke difference between the first initial position and the first stop position and an area of the piston; a first calibration brake liquid volume pushed by the piston is obtained according to the preset pressure and a preset P-V curve. The P-V curve is used to describe a mapping relationship between the cylinder pressure and the pushed brake liquid volume.

[0029] A difference between the first actual brake liquid volume and the first calibration brake liquid volume is a current gas content volume of the brake system, and the gas content is taken as an error of the detection method itself, that is, a detection deviation value .

[0030] Optionally, the preset pressure can be determined by the following method: S1, determining a minimum brake liquid discharge amount capable of exhausting gas in the electric cylinder circuit; S2, determining a remaining brake liquid amount of the electric cylinder based on the minimum brake liquid discharge amount; S3, determining a maximum pressure building pressure value that can be achieved by the remaining brake liquid amount in the electric cylinder; S4, determining a minimum pressure value in a linear region of the P-V curve; The present example ensures the accuracy of measurement by using the linear region of the P-V curve.

[0031] S5, determining the preset pressure in an interval range of the maximum pressure building pressure value and the minimum pressure value.

[0032] Optionally, a median value of the maximum pressure building pressure value and the minimum pressure value can be taken as the preset pressure.

[0033] Step 103, supplementing the electric cylinder with liquid.

[0034] That is, the electric cylinder is depressurized, the piston is retracted, the supplementing of liquid is started, and the brake liquid (possibly with air) in the brake pipeline is sucked into the electric cylinder until the supplementing of liquid is completed.

[0035] Step 104, after the supplementing of liquid, the electric cylinder is subjected to a second pressure building according to the preset pressure, a second actual brake liquid volume pushed by the piston in the second pressure building process and a second calibration brake liquid volume are determined, and a difference between the second actual brake liquid volume and the second calibration brake liquid volume is taken as an initial gas content of the electric cylinder circuit.

[0036] It should be noted that the second pressure build-up process can refer to the first pressure build-up process in step 102, using the same method to obtain the second actual brake fluid volume and the second calibrated brake fluid volume. The only difference is that the first pressure build-up is performed after bleeding the electric cylinder circuit, while the second pressure build-up is performed after adding fluid to the electric cylinder. Therefore, the second pressure build-up process will not be described in detail here.

[0037] The difference between the second actual brake fluid volume and the second calibrated brake fluid volume during the second pressure build-up process is the current gas content volume of the braking system. This gas content is taken as the gas content containing error, i.e., the initial gas content. .

[0038] Step 105: Determine the gas content of the electric cylinder circuit based on the initial gas content and the detection deviation value.

[0039] In some embodiments of this disclosure, due to the initial gas content Since the gas content contains errors, the difference between the initial gas content and the detection deviation value can be calculated to obtain the gas content of the electric cylinder circuit. .

[0040] In some embodiments of this disclosure, the gas content may also be... The gas content is compared with the set threshold for exceeding the gas content limit; when the gas content is greater than or equal to the threshold for exceeding the gas content limit, it is determined that the gas content of the Onebox hydraulic braking system exceeds the limit, and a gas content exceeding the limit alarm message is generated.

[0041] In some embodiments of this disclosure, after determining the gas content in the electric cylinder circuit, the braking system can be reset to control the depressurization of the electric cylinder and the piston return to its original position. If the target vehicle is in a stable driving state, all booster solenoid valves and depressurizer solenoid valves on the inlet and return valve lines also need to be opened.

[0042] By implementing the embodiments of this disclosure, the inherent errors of the indirect detection method are taken into account. By pushing the piston to discharge brake fluid gas from the detection circuit, the detection deviation value is calculated, and the gas content of the braking system is detected. This improves the accuracy and reliability of gas content detection and enhances vehicle safety.

[0043] Figure 3 This is a schematic diagram of a gas detection device based on a Onebox hydraulic braking system, provided as an embodiment of this disclosure. Figure 3 As shown, the gas detection device based on the Onebox hydraulic braking system may include: an exhaust module 301, a first pressure building module 302, a fluid replenishment module 303, a second pressure building module 304, and a detection module 305.

[0044] The exhaust module 301 is used to exhaust the electric cylinder circuit in response to the target vehicle meeting the gas detection conditions. The electric cylinder circuit is the passage between the electric cylinder and the electric cylinder isolation valve.

[0045] Gas detection conditions include the target vehicle being in either a power-on self-test state or a stable driving state. The power-on self-test state includes ignition cycle starting, no braking, and the vehicle being stationary. The stable driving state includes the target vehicle's speed being within a preset threshold range, the rate of speed change being less than a preset threshold, and both the boost and depressurization solenoid valves being closed.

[0046] The first pressure-building module 302 is used to build up the pressure of the electric cylinder for the first time according to the preset pressure, determine the first actual brake fluid volume pushed by the piston and the first standard brake fluid volume during the first pressure-building process, and use the difference between the first actual brake fluid volume and the first standard brake fluid volume as the detection deviation value.

[0047] In some embodiments of this disclosure, the first pressure-building module 302 is specifically used for: determining the first initial position of the piston; pushing the piston and stopping pushing when the pressure of the electric cylinder reaches a preset pressure, and determining the first stop position of the piston; determining the first actual brake fluid volume pushed by the piston based on the piston stroke difference between the first initial position and the first stop position and the piston area; and obtaining the first standardized brake fluid volume pushed by the piston based on the preset pressure and the preset PV curve, wherein the PV curve is used to describe the mapping relationship between the cylinder pressure and the brake fluid volume.

[0048] The fluid replenishment module 303 is used to replenish fluid to the electric cylinder.

[0049] The second pressure-building module 304 is used to build up the pressure of the electric cylinder a second time according to the preset pressure after replenishment. It determines the second actual brake fluid volume pushed by the piston and the second standard brake fluid volume during the second pressure-building process, and uses the difference between the second actual brake fluid volume and the second standard brake fluid volume as the initial gas content of the electric cylinder circuit.

[0050] The detection module 305 is used to determine the gas content of the electric cylinder circuit based on the initial gas content and the detection deviation value.

[0051] In some embodiments of this disclosure, such as Figure 3 Based on the illustrated embodiment, the gas detection device based on the Onebox hydraulic braking system may further include a determination module. The determination module is used to: determine the minimum brake fluid discharge amount required to vent gas from the electric cylinder circuit; determine the remaining brake fluid volume in the electric cylinder based on the minimum brake fluid discharge amount; determine the maximum pressure build-up value of the remaining brake fluid volume; determine the minimum pressure value in the linear region of the PV curve; and determine a preset pressure within the range between the maximum pressure build-up value and the minimum pressure value.

[0052] In some embodiments of this disclosure, the median of the maximum pressure build-up and the minimum pressure is used as the preset pressure.

[0053] In some embodiments of this disclosure, such as Figure 3 Based on the illustrated embodiment, the gas detection device for the Onebox hydraulic braking system may further include an alarm module. The alarm module is used to: compare the gas content with a set gas content exceeding a threshold; when the gas content is greater than or equal to the gas content exceeding the threshold, determine that the gas content of the Onebox hydraulic braking system exceeds the limit, and generate a gas content exceeding alarm message.

[0054] In some embodiments of this disclosure, such as Figure 3 Based on the illustrated embodiment, the gas detection device based on the Onebox hydraulic braking system may further include a reset module. The reset module is used to: after determining the gas content in the electric cylinder circuit, control the electric cylinder to depressurize and return the piston to its original position.

[0055] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0056] To implement the above embodiments, this disclosure also proposes an electronic device, including: a processor and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0057] To implement the above embodiments, this disclosure also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0058] To implement the above embodiments, this disclosure also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0059] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0062] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0063] It should be understood that various parts of this disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0064] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments.

[0065] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0066] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A gas detection method based on a Onebox hydraulic braking system, wherein the electric cylinder unit in the Onebox hydraulic braking system is connected to the inlet and return valves of the reservoir and the wheel respectively via an electric cylinder isolation valve, the electric cylinder unit comprising an electric cylinder, a motor, and a piston, and a pressure boosting solenoid valve and a pressure reducing solenoid valve are respectively installed on the inlet and return valves; characterized in that, The method includes the following steps: In response to the target vehicle meeting the gas detection conditions, exhaust is performed on the electric cylinder circuit, which is the passage between the electric cylinder and the electric cylinder isolation valve; The electric cylinder is pressurized for the first time according to the preset pressure. The first actual brake fluid volume pushed by the piston and the first calibrated brake fluid volume are determined during the first pressurization process. The difference between the first actual brake fluid volume and the first calibrated brake fluid volume is used as the detection deviation value. The electric cylinder is replenished with fluid; After replenishing the fluid, the electric cylinder is pressurized a second time according to the preset pressure. The second actual brake fluid volume pushed by the piston and the second standard brake fluid volume are determined during the second pressurization process. The difference between the second actual brake fluid volume and the second standard brake fluid volume is used as the initial gas content of the electric cylinder circuit. The gas content of the electric cylinder circuit is determined based on the initial gas content and the detection deviation value.

2. The method according to claim 1, characterized in that, Determining the first actual brake fluid volume and the first calibrated brake fluid volume pushed by the piston during the first pressure build-up process includes: Determine the first initial position of the piston; The piston is pushed until the pressure of the electric cylinder reaches the preset pressure, at which point the pushing stops, and the first stop position of the piston is determined. The first actual brake fluid volume pushed by the piston is determined based on the piston stroke difference between the first initial position and the first stop position and the piston area; Based on the preset pressure and the preset PV curve, the first standard braking fluid volume driven by the piston is obtained. The PV curve is used to describe the mapping relationship between cylinder pressure and braking fluid volume.

3. The method according to claim 2, characterized in that, The preset pressure is determined in the following way: Determine the minimum amount of brake fluid that can vent the gas in the electric cylinder circuit; The remaining brake fluid volume of the electric cylinder is determined based on the minimum brake fluid discharge volume; Determine the maximum pressure build-up value for the remaining brake fluid volume; Determine the minimum pressure value in the linear region of the PV curve; The preset pressure is determined within the range between the maximum pressure build-up value and the minimum pressure value.

4. The method according to claim 3, characterized in that, Determining the preset pressure within the range of the maximum pressure build-up value and the minimum pressure value includes: The midpoint between the maximum pressure build-up value and the minimum pressure value is taken as the preset pressure.

5. The method according to claim 1, characterized in that, The gas detection conditions include the target vehicle being in a vehicle power-on self-test state or a stable driving state. The vehicle's power-on self-test status includes ignition cycle starting, no braking, and the vehicle being stationary. The stable driving state includes the target vehicle's speed being within a preset threshold range, the speed change rate being less than a preset change threshold, and the boost solenoid valve and the depressurization solenoid valve being in the closed state.

6. The method according to claim 1, characterized in that, The method further includes: The gas content is compared with a set threshold for exceeding the gas content limit; When the gas content is greater than or equal to the gas content exceeding the threshold, it is determined that the gas content of the Onebox hydraulic braking system exceeds the standard, and a gas content exceeding the standard alarm message is generated.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: After determining the gas content in the electric cylinder circuit, the electric cylinder is depressurized, and the piston returns to its original position.

8. A gas detection device based on a Onebox hydraulic braking system, wherein the electric cylinder unit in the Onebox hydraulic braking system is connected to the inlet and return valves of the reservoir and the wheel respectively via an electric cylinder isolation valve, the electric cylinder unit comprising an electric cylinder, a motor and a piston, and a pressure boosting solenoid valve and a pressure reducing solenoid valve respectively provided on the inlet and return valves; characterized in that, The device includes: An exhaust module is used to exhaust gas from the electric cylinder circuit in response to the target vehicle meeting the gas detection conditions. The electric cylinder circuit is the passage between the electric cylinder and the electric cylinder isolation valve. The first pressure building module is used to build up the pressure of the electric cylinder for the first time according to the preset pressure, determine the first actual brake fluid volume pushed by the piston and the first standard brake fluid volume during the first pressure building process, and use the difference between the first actual brake fluid volume and the first standard brake fluid volume as the detection deviation value. A fluid replenishment module is used to replenish fluid to the electric cylinder; The second pressure-building module is used to build up the pressure of the electric cylinder a second time according to the preset pressure after replenishment, determine the second actual brake fluid volume pushed by the piston and the second standard brake fluid volume during the second pressure-building process, and use the difference between the second actual brake fluid volume and the second standard brake fluid volume as the initial gas content of the electric cylinder circuit. The detection module is used to determine the gas content of the electric cylinder circuit based on the initial gas content and the detection deviation value.

9. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-7.

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