WO2025020797A1 - Brake system leakage monitoring method - Google Patents

Abstract

Disclosed in the present invention is a brake system leakage monitoring method. In the method, an electronic booster (Ebooster) controller in an Ebooster is used to monitor brake fluid pressures at different positions in a brake system and wheel speeds, a set determination rule and process is used to identify whether the brake system has a leakage risk, and a specific brake fluid leakage position is found when the brake system has a leakage risk.

Description

A method for monitoring leakage of a brake system

CROSS-REFERENCE TO RELATED APPLICATIONS

The embodiments of this application are based on Chinese patent application with application number 202310907267.8 and application date July 21, 2023, and claim the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into the embodiments of this application as a reference.

Technical Field

The present invention relates to the technical field of brake system monitoring, and in particular to a brake system leakage monitoring method.

Background Art

This patent is mainly aimed at vehicles with electric drive systems, including hybrid and pure electric vehicles; it involves a method for active monitoring and alarm of brake fluid leakage in the braking system.

In recent years, with the vigorous development of automobiles towards electrification, intelligence, and networking; on the one hand, the proportion of electronic automobile parts continues to increase, and the brake system, as a key subsystem of the automobile, has also been gradually replaced by the electronic power-assisted braking solution from the traditional vacuum power-assisted solution. The electronic brake booster Ebooster, unlike the vacuum booster, integrates signals such as the brake pedal stroke and power-assisted current, providing greater possibilities for creating new functions. On the other hand, due to the intelligence of vehicles, higher requirements are also placed on the safety of automobiles. The current mainstream braking system uses hydraulic transmission to push the caliper piston; after a long period of use, or the pipeline is damaged by collision, the brake fluid leaks, and the basic braking system gradually loses its braking force; for this kind of fault condition, the current automobile system can only rely on the liquid level sensor in the brake reservoir to monitor and alarm when the brake fluid leaks very seriously, and ordinary drivers cannot predict it in advance, which poses a serious safety hazard.

Prior art 1 discloses a solution that places a liquid level sensor in the brake fluid reservoir and connects it to the controller through a hard wire; when the sensor detects that the liquid level is very low, it will automatically alarm. The disadvantage of this solution is that it will only alarm when the leakage is very serious and the liquid level is lower than the minimum threshold, and it cannot provide In addition, this solution can only monitor the brake fluid level in the reservoir, but cannot determine the specific leakage location.

Prior art 2 discloses a solution, which is mainly to place a liquid level closing switch and other sensors, such as temperature and water detectors, in the brake fluid reservoir; when the brake fluid in the reservoir is abnormal, an alarm will be triggered. The disadvantage of this solution is that the main purpose is only to monitor the amount of brake fluid in the reservoir, and it cannot directly monitor the leakage of brake fluid, so slow leakage cannot be effectively monitored, and the cost is high due to the coordination of monitoring with multiple sensors.

Summary of the invention

The object of the present invention is to provide a brake system leakage monitoring method to achieve timely and accurate identification of the leakage position in the brake system.

In order to solve the above technical problems, the present invention provides a technical solution: a brake system leakage monitoring method, which is applicable to the brake system of an EBbooster electronic booster, in which a brake master cylinder is connected to a first pipeline and a second pipeline is connected to a brake hydraulic control unit, the pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit, and the pipeline between the brake hydraulic control unit and the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder constitutes a secondary brake circuit;

The method includes:

Collect the brake fluid pressure of the master cylinder, the first pipeline, and the second pipeline in real time; and determine whether to perform the subsequent brake fluid leakage position determination process according to the brake fluid pressure of the master cylinder, the first pipeline, the second pipeline, and the pedal stroke;

According to the brake fluid pressures of the brake master cylinder, the first pipeline, the second pipeline, and the pedal stroke, it is determined that the brake fluid leakage position is located in the primary brake circuit or the secondary brake circuit;

When it is determined that the brake fluid leakage position is located in the primary brake circuit, the brake fluid leakage position is determined to be located in the brake master cylinder, the first pipeline, the second pipeline, and the brake hydraulic pressure and pedal stroke according to the brake master cylinder, the first pipeline, the second pipeline, and the brake hydraulic pressure and pedal stroke. cylinder or the first pipeline or the second pipeline; when it is determined that the brake fluid leakage location is the secondary brake circuit and the current driving road surface is a homogeneous road surface, the brake fluid leakage location is determined to be the left front wheel caliper wheel cylinder or the right front wheel caliper wheel cylinder or the left rear wheel caliper wheel cylinder or the right rear wheel caliper wheel cylinder according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed.

As a second aspect, the present invention further provides a brake system with a leakage monitoring function for implementing the above-mentioned brake system leakage monitoring method, comprising a brake pedal, an EBbooster electronic booster, a brake master cylinder, a brake hydraulic control unit, a left front wheel caliper wheel cylinder, a right front wheel caliper wheel cylinder, a left rear wheel caliper wheel cylinder, a right rear wheel caliper wheel cylinder, a first brake pressure sensor, a second brake pressure sensor, a third brake pressure sensor, and wheel speed sensors arranged on four wheels;

The EBbooster electronic booster includes an input push rod, a travel sensor, an EBbooster controller and a boost motor; the brake pedal is transmission-connected to the input push rod, the travel sensor is arranged on the input push rod and is electrically connected to the EBbooster controller, and the boost motor is electrically connected to the EBbooster controller;

The power-assisting motor is connected to the piston of the brake master cylinder through a first pipeline and a second pipeline, and the brake hydraulic control unit is connected to the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder through pipelines, respectively; wherein, the pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit, and the pipeline between the brake hydraulic control unit and the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder constitutes a secondary brake circuit;

The first brake pressure sensor is arranged in the brake master cylinder, the second brake pressure sensor is arranged in the first pipeline, and the third brake pressure sensor is arranged in the second pipeline; the first, second and third brake pressure sensors are all electrically connected to the EBbooster electronic booster;

The wheel speed sensor is electrically connected to the EBbooster electronic booster;

The first brake pressure sensor, the second brake pressure sensor, and the third brake pressure sensor are used to collect brake hydraulic pressures PS ₁ , PS ₂ , and PS ₃ of the brake master cylinder, the first pipeline, and the second pipeline, respectively;

The wheel speed sensor is used to collect the left front wheel speed ω _FL , the right front wheel speed ω _FR , the left rear wheel speed ω _RL , and the right rear wheel speed ω _RR ;

The EBbooster controller obtains the target brake fluid pressure PS _tar through the pedal stroke signal of the stroke sensor, and determines whether there is a brake fluid leakage and the specific brake fluid leakage location in combination with PS ₁ , PS ₂ , PS ₃ , ω _FL , ω _FR , ω _RL , ω _RR .

As a third aspect, the present invention further provides a computer, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned brake system leakage monitoring method when executing the computer program.

As a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the brake system leakage monitoring method described above.

As a fifth aspect, the present invention also provides a vehicle having the braking system with leakage monitoring function as described above.

The beneficial effects of the present invention are: by monitoring the brake fluid pressure and wheel speed at different positions in the brake system, it is possible to determine whether the vehicle has a risk of brake fluid leakage and the specific location of the brake fluid leakage. Compared with the prior art, the judgment of brake fluid leakage is more timely and accurate, and can help the owner or maintenance personnel quickly confirm the fault location. The sensors required by the method are all sensors owned by the vehicle, and the calculation control is realized through the EBbooster controller, without adding additional hardware costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a brake system with a leakage monitoring function according to an embodiment of the present invention;

FIG. 2 is a diagram showing a corresponding relationship between a pedal travel signal and a target brake hydraulic pressure according to an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the described The embodiments of the present disclosure and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present disclosure.

A brake system leakage monitoring method, the method is implemented based on a brake system using an EBbooster electronic booster, in which a brake master cylinder is connected to a first pipeline and a second pipeline is connected to a brake hydraulic control unit, the pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit, and the pipelines between the brake hydraulic control unit and a left front wheel caliper wheel cylinder, a right front wheel caliper wheel cylinder, a left rear wheel caliper wheel cylinder, and a right rear wheel caliper wheel cylinder constitute a secondary brake circuit;

The method comprises the following steps:

S1, real-time acquisition of brake hydraulic pressure PS ₁ , PS ₂ , PS ₃ of the brake master cylinder, the first pipeline, and the second pipeline;

S2. During braking, the EBbooster controller in the EBbooster electronic booster obtains the target brake hydraulic pressure PS _tar by looking up the table according to the pedal travel signal; and obtains the average of PS ₁ , PS ₂ , and PS ₃ and calculate the PS _tar with The difference ΔPS;

When ΔPS ≥ 0, the subsequent brake fluid leakage position determination process is enabled; otherwise, the process returns to S1;

S3. If ΔPS≤MAX{1bar,1%×PS _tra }, it is determined that the primary brake circuit is normal and S5 is executed. Otherwise, it is determined that there is leakage in the primary brake circuit and S4 is executed.

S4, respectively obtain the differences ΔPS ₁ , ΔPS ₂ , ΔPS ₃ between PS _tra and PS ₁ , PS ₂ , PS ₃ ;

If ΔPS ₁ >MAX{1bar,1%×PS _tra } is satisfied at the same time
ΔPS ₂ >MAX{1bar,1%× _PStra }
ΔPS ₃ >MAX{1bar,1%× _PStra }

Then the leakage location is judged to be the brake master cylinder;

If ΔPS ₁ <MAX{1bar,1%×PS _tra } is satisfied at the same time
ΔPS ₂ >MAX{1bar,1%× _PStra }
ΔPS ₃ <MAX{1bar,1%×PS _tra }

Then it is determined that the leakage location is the first pipeline;

If ΔPS ₁ <MAX{1bar,1%×PS _tra } is satisfied at the same time
ΔPS ₂ <MAX{1bar,1%×PS _tra }
ΔPS ₃ >MAX{1bar,1%× _PStra }

Then it is determined that the leakage location is the second pipeline;

S5. If the current braking condition is a normal braking condition (and the vehicle's stability control function ABS or AYC is in a non-triggered state, and the braking condition is obtained by the EBbooster controller through the electronic power assist mode in its program), and the current driving road surface is a homogeneous road surface, then proceed to the subsequent steps; the current driving road surface judgment is specifically:

Collect the left front wheel speed ω _FL , the right front wheel speed ω _FR , the left rear wheel speed ω _RL , and the right rear wheel speed ω _RR , and calculate the left front wheel deceleration Right front wheel deceleration Left rear wheel deceleration Right rear wheel deceleration Get the average of the two front wheel decelerations and the average of the two rear wheel decelerations

If both are satisfied,

It is judged that the current driving road surface is a homogeneous road surface;

S6. Select three braking actions with target brake fluid pressure in the range of (25 bar, 50 bar) under normal braking conditions and driving on homogeneous road conditions, and take the average of the four-wheel deceleration corresponding to the three selected braking actions according to the left front wheel, right front wheel, left rear wheel, and right rear wheel, and obtain Then there is,

If both meet

The leak position is determined to be the left front wheel caliper wheel cylinder;

If both meet

The leak location is determined to be the right front wheel caliper wheel cylinder;

If both meet

The leak location is determined to be the left rear wheel caliper wheel cylinder;

If both meet

The leakage location is determined to be the right rear wheel caliper wheel cylinder.

Referring to FIG1 , a brake system with a leakage monitoring function for implementing the above-mentioned brake system leakage monitoring method includes a brake pedal, an EBbooster electronic booster, a brake master cylinder, a brake hydraulic control unit, a left front wheel caliper wheel cylinder, a right front wheel caliper wheel cylinder, a left rear wheel caliper wheel cylinder, a right rear wheel caliper wheel cylinder, a first brake pressure sensor, a second brake pressure sensor, a third brake pressure sensor, and wheel speed sensors arranged on four wheels;

The EBbooster electronic booster includes an input push rod, a travel sensor, an EBbooster controller and a boost motor; the brake pedal is transmission-connected to the input push rod, the travel sensor is arranged on the input push rod and is electrically connected to the EBbooster controller, and the boost motor is electrically connected to the EBbooster controller;

The power-assisting motor is connected to the piston of the brake master cylinder through a first pipeline and a second pipeline, and the brake hydraulic control unit is connected to the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder through pipelines, respectively; wherein, the pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit, and the pipeline between the brake hydraulic control unit and the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder constitutes a secondary brake circuit;

The first brake pressure sensor is arranged in the brake master cylinder, the second brake pressure sensor is arranged in the first pipeline, and the third brake pressure sensor is arranged in the second pipeline; the first, second and third brake pressure sensors are all electrically connected to the EBbooster electronic booster;

The wheel speed sensor is electrically connected to the EBbooster electronic booster;

The first brake pressure sensor, the second brake pressure sensor, and the third brake pressure sensor are used to collect brake hydraulic pressures PS ₁ , PS ₂ , and PS ₃ of the brake master cylinder, the first pipeline, and the second pipeline, respectively;

The wheel speed sensor is used to collect the left front wheel speed ω _FL , the right front wheel speed ω _FR , the left rear wheel speed ω _RL , and the right rear wheel speed ω _RR ;

The EBbooster controller obtains the target brake fluid pressure PS _tra through the pedal stroke signal of the stroke sensor, and determines whether there is a brake fluid leakage and the specific brake fluid leakage location in combination with PS ₁ , PS ₂ , PS ₃ , ω _FL , ω _FR , ω _RL , ω _RR .

A computer comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned braking system leakage monitoring method when executing the computer program.

A computer-readable storage medium stores a computer program, which implements the steps of the above-mentioned brake system leakage monitoring method when executed by a processor.

A car has the above-mentioned brake system with leakage monitoring function.

The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (10)

A brake system leakage monitoring method, characterized in that: the method is applicable to a brake system of an EBbooster electronic booster, in which a brake master cylinder is connected to a first pipeline and a second pipeline is connected to a brake hydraulic control unit, the pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit, and the pipelines between the brake hydraulic control unit and a left front wheel caliper wheel cylinder, a right front wheel caliper wheel cylinder, a left rear wheel caliper wheel cylinder, and a right rear wheel caliper wheel cylinder constitute a secondary brake circuit; The method includes: Collect the brake fluid pressure of the master cylinder, the first pipeline, and the second pipeline in real time; and determine whether to perform the subsequent brake fluid leakage position determination process according to the brake fluid pressure of the master cylinder, the first pipeline, the second pipeline, and the pedal stroke; According to the brake fluid pressures of the brake master cylinder, the first pipeline, the second pipeline, and the pedal stroke, it is determined that the brake fluid leakage position is located in the primary brake circuit or the secondary brake circuit; When it is determined that the brake fluid leakage location is located in the primary brake circuit, the brake fluid leakage location is determined to be in the brake master cylinder, the first pipeline, the second pipeline, and the pedal stroke; when it is determined that the brake fluid leakage location is the secondary brake circuit and the current driving road surface is a homogeneous road surface, the brake fluid leakage location is determined to be in the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, or the right rear wheel caliper wheel cylinder according to the left front wheel speed, the right front wheel speed, the left rear wheel speed, and the right rear wheel speed. The brake system leakage monitoring method according to claim 1 is characterized in that: the process of determining whether to perform a subsequent brake fluid leakage position determination process according to the brake fluid pressure of the brake master cylinder, the first pipeline, the second pipeline, and the pedal stroke is as follows: During braking, the EBbooster controller in the EBbooster electronic booster obtains the target brake hydraulic pressure PS _tar according to the pedal travel signal by looking up the table; the brake hydraulic pressures of the master cylinder, the first pipeline, and the second pipeline are PS ₁ , PS ₂ , and PS ₃ respectively, and the average of PS ₁ , PS ₂ , and PS ₃ is obtained and calculate the PS _tar with The difference ΔPS; When ΔPS ≥ 0, the subsequent brake fluid leakage position determination process is enabled, otherwise the brake fluid pressures of the brake master cylinder, the first pipeline, and the second pipeline are continuously collected and ΔPS is calculated. The brake system leakage monitoring method according to claim 2 is characterized in that: the preliminary judgment process of the brake fluid leakage position is as follows: If ΔPS≤MAX{αbar,β％×PS _tar }, the brake fluid leakage position is determined to be located in the secondary brake circuit, otherwise the brake fluid leakage position is determined to be located in the primary brake circuit; wherein α is a preset pressure value, and β is a preset percentage value. The brake system leakage monitoring method according to claim 3 is characterized in that: when it is determined that the brake fluid leakage position is located in the primary brake circuit, the specific judgment process of the brake fluid leakage position is as follows: Calculate the differences ΔPS ₁ , ΔPS ₂ , and ΔPS ₃ between PS _tar and PS ₁ , PS ₂ , and PS _{3 ,} respectively; If ΔPS ₁ >MAX{αbar,β％×PS _tar }
ΔPS ₂ >MAX{αbar,β%×PS _tar }
ΔPS ₃ >MAX{αbar,β%×PS _tar } Then the leakage location is judged to be the brake master cylinder; If ΔPS ₁ < MAX{αbar,β%×PS _tar }
ΔPS ₂ >MAX{αbar,β%×PS _tar }
ΔPS ₃ <MAX{αbar,β%×PS _tar } Then it is determined that the leakage location is the first pipeline; If ΔPS ₁ < MAX{αbar,β%×PS _tar }
ΔPS ₂ <MAX{αbar,β%×PS _tar }
ΔPS ₃ >MAX{αbar,β%×PS _tar } It is determined that the leakage location is the second pipeline. The brake system leakage monitoring method according to claim 3 is characterized in that: the mean road surface judgment method is specifically: When it is determined that the brake fluid leakage position is located in the second-level brake circuit, the specific judgment process of the brake fluid leakage position is as follows: Collect the left front wheel speed ω _FL , the right front wheel speed ω _FR , the left rear wheel speed ω _RL , and the right rear wheel speed ω _RR , and calculate the left front wheel deceleration Right front wheel deceleration Left rear wheel deceleration Right rear wheel deceleration Get the average of the two front wheel decelerations and the average of the two rear wheel decelerations If both are satisfied,



The current driving road surface is judged to be a homogeneous road surface; wherein γ is a preset percentage value. The brake system leakage monitoring method according to claim 3 is characterized in that: when it is determined that the brake fluid leakage position is located in the secondary brake circuit and the current driving road surface is a homogeneous road surface, the specific judgment process of the brake fluid leakage position is as follows: Select several braking actions with target brake fluid pressure within a certain threshold under normal braking conditions and driving on homogeneous road conditions, and take the average of the four-wheel deceleration corresponding to the selected several braking actions according to the left front wheel, right front wheel, left rear wheel, and right rear wheel, and get Then there is,

If both meet



The leak position is determined to be the left front wheel caliper wheel cylinder; If both meet



The leak location is determined to be the right front wheel caliper wheel cylinder; If both meet



The leak location is determined to be the left rear wheel caliper wheel cylinder; If both meet



The leak location is determined to be the right rear wheel caliper wheel cylinder; Where ε and μ are preset percentage values. A brake system with a leakage monitoring function for implementing the brake system leakage monitoring method according to any one of claims 1 to 6, characterized in that it comprises a brake pedal, an EBbooster electronic booster, a brake master cylinder, a brake hydraulic control unit, a left front wheel caliper wheel cylinder, a right front wheel caliper wheel cylinder, a left rear wheel caliper wheel cylinder, a right rear wheel caliper wheel cylinder, a first brake pressure sensor, a second brake pressure sensor, a third brake pressure sensor, and wheel speed sensors arranged on four wheels; The EBbooster electronic booster includes an input push rod, a travel sensor, an EBbooster controller and a boost motor; the brake pedal is transmission-connected to the input push rod, the travel sensor is arranged on the input push rod and is electrically connected to the EBbooster controller, and the boost motor is electrically connected to the EBbooster controller; The booster motor is connected to the piston of the brake master cylinder through a first pipeline and a second pipeline, and the brake hydraulic control unit is connected to the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder through pipelines. The pipeline between the brake master cylinder and the brake hydraulic control unit constitutes a primary brake circuit. The brake hydraulic control unit is connected to the left front wheel caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder through pipelines. The pipelines between the caliper wheel cylinder, the right front wheel caliper wheel cylinder, the left rear wheel caliper wheel cylinder, and the right rear wheel caliper wheel cylinder constitute a secondary brake circuit; The first brake pressure sensor is arranged in the brake master cylinder, the second brake pressure sensor is arranged in the first pipeline, and the third brake pressure sensor is arranged in the second pipeline; the first, second and third brake pressure sensors are all electrically connected to the EBbooster electronic booster; The wheel speed sensor is electrically connected to the EBbooster electronic booster; The first brake pressure sensor, the second brake pressure sensor, and the third brake pressure sensor are used to collect brake hydraulic pressures PS ₁ , PS ₂ , and PS ₃ of the brake master cylinder, the first pipeline, and the second pipeline, respectively; The wheel speed sensor is used to collect the left front wheel speed ω _FL , the right front wheel speed ω _FR , the left rear wheel speed ω _RL , and the right rear wheel speed ω _RR ; The EBbooster controller obtains the target brake fluid pressure PS _tar through the pedal stroke signal of the stroke sensor, and determines whether there is a brake fluid leakage and the specific brake fluid leakage location in combination with PS ₁ , PS ₂ , PS ₃ , ω _FL , ω _FR , ω _RL , ω _RR . A computer comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the brake system leakage monitoring method according to any one of claims 1 to 6 when executing the computer program. A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of the brake system leakage monitoring method according to any one of claims 1 to 6 are implemented. A car, characterized in that it has the brake system with leakage monitoring function as claimed in claim 7.