Vehicle EPB system and control method thereof

Abstract

The invention provides a vehicle EPB system and a control method thereof. The vehicle EPB system comprises an EPB solenoid valve, a signal acquisition module, a processing unit and an execution protection module, and the EPB solenoid valve is used for controlling clamping or releasing of a brake; the signal acquisition module is used for acquiring a temperature signal and a wheel speed signal; the processing unit is used for calculating the rotating speed difference of the two coaxial wheels, judging whether the rotating speed difference exceeds a first threshold value or not when the vehicle is in a straight driving state, monitoring whether the temperature of the brake exceeds a second threshold value or not, and judging that the EPB system is in a dragging state when the rotating speed difference is larger than the first threshold value and the temperature exceeds the second threshold value; the execution protection module comprises an active release sub-module and a limited power request sub-module, and in the dragging state, the active release sub-module drives an EPB electromagnetic valve to release a brake and sends a limited power request signal to a vehicle engine through the limited power request sub-module. According to the invention, the problem of lack of effective monitoring means for EPB dragging wear faults is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile electronic control and safety technology, and in particular to a vehicle EPB system and a control method thereof. BACKGROUND

[0002] In the field of commercial vehicles, truck, bus and other vehicle models generally use a pneumatic electronic parking brake system (EPB) to ensure driving safety and parking stability. The system precisely controls the electromagnetic valve through electric control signals to drive the pneumatic circuit to achieve flexible clamping and release of the brake, thereby playing a key role in improving brake efficiency and automation level.

[0003] However, commercial vehicles operate in complex and harsh environments, often facing high load, long distance driving, and frequent start-stop conditions, which poses a serious challenge to the EPB system. In actual use, the valve body is prone to jamming due to dust and impurities entering or frequent operation; the return spring is prone to fatigue and fracture under long-term alternating stress; and the air circuit may leak or be blocked due to aging of the sealing element, pipe damage or foreign matter blockage. These problems can easily cause the brake to fail to completely release the braking state after executing the "release" instruction, i.e., a "dragging" fault.

[0004] The dragging fault is serious and has many aspects. The high temperature generated by the long-time friction between the brake pad and the brake disc / drum can easily ignite the tire or surrounding flammable components, causing a vehicle fire accident, which seriously threatens the safety of the driver and passengers and the safety of goods and property. At the same time, the continuous driving resistance can greatly increase the power consumption and fuel consumption of the vehicle, increase the operating cost, reduce the range, and affect the transportation efficiency. In addition, it can also accelerate the wear of the parts of the braking system, shorten its service life, cause the braking system to fail early, increase the maintenance cost and vehicle downtime.

[0005] Currently, there is a lack of effective and real-time monitoring means for EPB dragging faults in the industry, which mainly relies on the subjective feelings of the driver or daily maintenance inspection, making it difficult to detect and handle the fault at an early stage, often causing serious damage or hidden safety hazards. Therefore, it is urgent to develop a system that can automatically and real-time diagnose the dragging fault and actively take protective measures. SUMMARY

[0006] The purpose of the present application is to provide a vehicle EPB system and a control method thereof to solve the technical problem of lack of effective and real-time monitoring means for pneumatic electronic parking brake system (EPB) dragging faults in the prior art.

[0007] In order to achieve the above-mentioned purpose of the present application, an embodiment of the present application provides a vehicle EPB system, the vehicle comprising a plurality of wheels and brakes, each brake corresponding to a wheel, wherein it comprises: EPB solenoid valve for converting electric control signal into pneumatic action to control brake clamping or releasing; signal acquisition module for acquiring temperature signals of each brake and wheel speed signals of each wheel; processing unit for calculating speed difference of two coaxial wheels based on wheel speed signals, and determining whether the speed difference exceeds a first threshold value when the vehicle is in straight driving state, and monitoring whether the brake temperature exceeds a second threshold value based on temperature signals, and determining that the EPB system is in drag state when the speed difference is greater than the first threshold value and the temperature exceeds the second threshold value; active release sub-module and power limiting request sub-module, in the drag state, the active release sub-module drives the EPB solenoid valve to release the brake, and the power limiting request sub-module sends a power limiting request signal to the engine of the vehicle to reduce the output torque.

[0008] As a further improvement of an embodiment of the application, the power limiting request sub-module sends the power limiting request signal to the engine through the vehicle CAN bus.

[0009] As a further improvement of an embodiment of the application, the active release sub-module directly drives the EPB solenoid valve to release the brake by generating a forced release instruction.

[0010] As a further improvement of an embodiment of the application, the signal acquisition module includes a plurality of temperature sensing units, each temperature sensing unit is arranged corresponding to one brake to obtain the temperature signal of the brake.

[0011] As a further improvement of an embodiment of the application, the signal acquisition module includes a plurality of wheel speed sensing units, each wheel speed sensing unit is arranged corresponding to one wheel and is used to obtain the wheel speed signal of the wheel.

[0012] As a further improvement of an embodiment of the application, the vehicle EPB system further includes an alarm prompt module, the alarm prompt module includes a first warning unit, the signal acquisition module includes a current sensing unit for acquiring a driving current waveform of the EPB solenoid valve, and the processing unit is used to determine whether the amplitude of the driving current waveform is greater than the amplitude of a predetermined standard release current waveform for a set time period, and the first warning unit is triggered for early warning when the speed difference is greater than a third threshold value or the amplitude of the driving current waveform is greater than the amplitude of the predetermined standard release current waveform for a set time period, wherein the third threshold value is less than the first threshold value.

[0013] As a further improvement of the embodiment of the present application, the alarm prompting module further comprises a second warning unit, and the processing unit triggers the second warning unit to give a warning when the EPB system is in the drag state.

[0014] As a further improvement of the embodiment of the present application, the execution protection module further comprises a remote reporting sub-module, and the remote reporting sub-module is configured to send the drag state information through wireless transmission when the EPB system is in the drag state.

[0015] The embodiment of the present application further provides a vehicle EPB system control method, which comprises the following steps: obtaining brake temperature signals and wheel speed signals of two coaxial wheels; calculating a rotational speed difference of the two coaxial wheels based on the wheel speed signals, and determining whether the rotational speed difference exceeds a first threshold value when the vehicle is in a straight driving state, and monitoring whether the brake temperature exceeds a second threshold value based on the temperature signals; generating a forced release instruction to directly drive an EPB electromagnetic valve to release the brake, and sending a power limiting request signal to an engine when the rotational speed difference is greater than the first threshold value and the temperature exceeds the second threshold value.

[0016] As a further improvement of the embodiment of the present application, the sending of the power limiting request signal to the engine comprises: sending the power limiting request signal to an engine ECU through a vehicle CAN bus; and after sending the power limiting request signal, reporting the drag state information to a remote management platform through wireless transmission.

[0017] As a further improvement of the embodiment of the present application, after the determination of whether the rotational speed difference exceeds the first threshold value when the vehicle is in the straight driving state and the monitoring of whether the brake temperature exceeds the second threshold value based on the temperature signals, the method further comprises: collecting an EPB electromagnetic valve driving current waveform, and determining whether an amplitude of the driving current waveform is greater than an amplitude of a predetermined standard release current waveform for more than a set time length; triggering a first warning unit to give a warning when the rotational speed difference is greater than a third threshold value or the amplitude of the driving current waveform is greater than the amplitude of the predetermined standard release current waveform for more than the set time length, wherein the third threshold value is less than the first threshold value. The determination that the rotational speed difference is greater than the first threshold value and the temperature exceeds the second threshold value further comprises triggering a second warning unit to give an alarm.

[0018] Compared with the prior art, the present application has the following beneficial effects: Through the complete safety closed loop from "warning" to "alarm" to "active intervention", especially the protection mechanism of the forced release and the power limiting linkage, the source of failure can be fundamentally removed and the accident consequences can be controlled, so that the safety is higher. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The overall framework diagram of the vehicle EPB system provided by an embodiment of the present application is shown in the figure. Figure 2 The work flow diagram of the vehicle EPB system control method provided by an embodiment of the present application is shown in the figure. Figure 3 The work flow diagram of a preferred embodiment of the vehicle EPB system control method provided by an embodiment of the present application is shown in the figure.

[0020] The above brief description of drawings includes the following reference signs: 1, EPB electromagnetic valve 2, signal acquisition module 3, processing unit 4, execution protection module 41, active release sub-module 42, power limit request sub-module 43, remote reporting sub-module 5, alarm prompt module DETAILED DESCRIPTION

[0021] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0022] It should be noted that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0023] In the present application, unless otherwise specified, the orientation words such as “up, down, top, bottom” are generally directed to the directions shown in the drawings, or are directed to the vertical, perpendicular or gravity directions of the components themselves; similarly, for the convenience of understanding and description, “inner, outer” refers to the inner and outer relative to the contour of each component itself, but the above orientation words are not used to limit the present application.

[0024] In order to solve the technical problem that the prior art lacks effective and real-time monitoring means for the drag grinding fault of the pneumatic electronic parking brake system (EPB), the present application provides a vehicle EPB system and a control method thereof.

[0025] The present application will be further described in detail below in combination with the accompanying drawings and specific embodiments.

[0026] Embodiment 1

[0027] As Figure 1As shown, an embodiment of the present application provides a vehicle EPB system, the vehicle in the embodiment includes a plurality of wheels and brakes, each brake corresponding to a wheel.

[0028] The vehicle EPB system includes an EPB electromagnetic valve 1, a signal acquisition module 2, a processing unit 3, an execution protection module 4, etc.

[0029] The EPB electromagnetic valve 1 is used to convert an electric control signal into a pneumatic action to control the brake clamping or release; The signal acquisition module 2 is used to acquire temperature signals of each brake and wheel speed signals of each wheel; The processing unit 3 is used to calculate the speed difference of two coaxial wheels based on the wheel speed signals, and determine whether the speed difference exceeds a first threshold value when the vehicle is in a straight driving state, and monitor whether the brake temperature exceeds a second threshold value based on the temperature signals, and determine that the EPB system is in a drag state when the speed difference is greater than the first threshold value and the temperature exceeds the second threshold value; the execution protection module 4 includes an active release submodule 41 and a power limiting request submodule 42, in the drag state, the active release submodule 41 drives the EPB electromagnetic valve 1 to release the brake, and sends a power limiting request signal to the engine of the vehicle through the power limiting request submodule 42 to reduce the output torque.

[0030] As the above technical solution, by acquiring temperature / wheel speed signals, then calculating the speed difference of two coaxial wheels, and determining whether the speed difference exceeds a first threshold value when the vehicle is in a straight driving state, and monitoring whether the brake temperature exceeds a second threshold value based on the temperature signals, and determining that the EPB system is in a drag state when the speed difference is greater than the first threshold value and the temperature exceeds the second threshold value. In the drag state, the active release submodule 41 drives the EPB electromagnetic valve 1 to release the brake, and sends a power limiting request signal to the engine of the vehicle through the power limiting request submodule 42 to reduce the output torque.

[0031] Further, in the embodiment, the power limiting request submodule 42 sends a power limiting request signal to the engine through the vehicle CAN bus.

[0032] Specifically, the SAE J1939 protocol can be used to encapsulate a data frame (identifier 0x0CF00400) containing a torque limit value and a fault flag, and directly transmitted to the CAN interface of the engine ECU. This design is compatible with diesel, natural gas and electric commercial vehicle power systems.

[0033] In other embodiments, optional ways include: transmitting digital signals through FlexRay or vehicle Ethernet, or connecting through 0-5V analog voltage signals through hardwires to achieve the same function. Further, the active release sub-module 41 in the embodiment generates a forced release instruction to directly drive the EPB electromagnetic valve 1 to release the brake.

[0034] Specifically, a relay circuit can be connected in parallel at the output end of the controller, and when the instruction is triggered, the battery voltage (12V / 24V) is directly connected to the electromagnetic valve coil to drive the valve core to open the exhaust passage. The current pulse intensity is ≥5A, and the duration is ≥200ms to ensure complete release.

[0035] Alternatively, other implementations can also be used, such as: building an H-bridge circuit with MOSFET (new energy vehicles), optical coupling isolation + Darlington tube amplification (compatible with old systems), or electromagnetic mechanical unlocking (no electricity in emergency). This hardware-level intervention can forcibly release the brake when the controller fails, with a response delay of <100ms.

[0036] Further, in the embodiment, the signal acquisition module 2 includes a plurality of temperature sensing units, each unit independently corresponding to one brake installation to obtain temperature signals in real time.

[0037] As a preferred embodiment, a non-contact infrared sensor can be used in the embodiment, which is installed 5-10mm away from the side of the brake caliper to detect the radiant heat of the brake disc friction surface (0-5V corresponding to 0-500℃), with a sampling frequency of 10Hz. The sensor shell is connected to the brake caliper body through an aluminum alloy heat conduction sheet.

[0038] Alternatively, other implementations can use, for example: a contact type K-type thermocouple embedded in the back of the brake shoe (suitable for drum brakes); an indirect calculation model based on hydraulic temperature and brake frequency (space-limited scenarios); or a single sensor combined with a light pipe to collect multiple brakes in time (low-cost solution). The temperature signal is transmitted through a shielded wire, and 100Hz RC filtering is used to suppress interference. When a fault occurs, the adjacent data interpolation compensation is started.

[0039] The signal acquisition module 2 also includes a plurality of wheel speed sensing units, each unit independently corresponding to one wheel installation for obtaining wheel speed signals in real time.

[0040] Preferably, a magneto-electric sensor (such as an ABS wheel speed sensor) can be used, which is installed near the wheel hub to generate a pulse signal (frequency proportional to speed) by detecting the rotation of the wheel teeth or magnetic ring, which is transmitted to the processing unit 3 through a shielded cable with a sampling frequency of 100Hz. The installation position should avoid the mud splashing area and vibration source to maintain accuracy.

[0041] Optionally, other embodiments can include: Hall sensor monitoring wheel hub magnetic field changes (ring gear design applicable); reading J1939 protocol wheel speed data from vehicle CAN bus (reducing hardware); or using optical encoders to detect spoke movement. Sensor mounts are adjustable, compatible with different wheelbase for drum and disc brake systems. Signal independence is ensured by one-to-one correspondence settings, signal processing uses 50Hz RC filtering to suppress interference, and redundant algorithms (such as adjacent wheel speed interpolation compensation) can be enabled in case of failure, improving diagnostic reliability.

[0042] Further, as a preferred embodiment, in the present embodiment the vehicle EPB system further comprises an alarm prompt module 5, which includes a first warning unit for providing early warning in case of early potential failure.

[0043] The signal acquisition module 2 integrates a current sensing unit (such as a Hall current sensor or a shunt resistor) in series in the drive circuit of the EPB solenoid valve 1 to acquire real-time drive current waveform. The standard implementation of the current sensing unit uses a non-invasive design installed on the solenoid valve power supply line, with a sampling frequency of 1 kHz to capture current amplitude changes (typical range 0-10A). The processing unit 3 processes the acquired waveform, which specifically includes: comparing the real-time current waveform with the pre-stored standard release current waveform (obtained through calibration tests, representing the reference waveform under normal release conditions); determining whether the real-time current amplitude is continuously greater than the standard waveform amplitude and exceeds a set time length (e.g. 500ms). This set time length is used to exclude transient interference (such as power fluctuations) to ensure diagnostic reliability. If the rotational speed difference is greater than a third threshold value (the third threshold value is set to 70% of the first threshold value, e.g. the first threshold value is 100rpm, the third threshold value is 70rpm) or the current waveform amplitude continuously exceeds the set time length, the processing unit 3 triggers the first warning unit to output a warning signal. The first warning unit is usually implemented as a yellow indicator light on the instrument panel, which is turned on through CAN bus commands.

[0044] In other embodiments, the current sensing unit can use different technical solutions: for example, using a Rogowski coil to implement high-frequency current detection, suitable for high electromagnetic interference environments; or using a digital current sensor to output digital signals through an I²C interface, simplifying data processing. The warning logic can also be extended: for example, dynamically adjusting the set time length through software algorithms (based on vehicle speed or ambient temperature), or indirectly obtaining current data from the vehicle bus when there is no dedicated sensor (such as analyzing ECU communication messages). The overall design ensures timely warning of early failures (such as slight sticking of the solenoid valve) to avoid failure escalation, while the third threshold value is set in stages to reduce false alarm rate and improve system robustness.

[0045] Further, the alarm prompt module 5 further comprises a second warning unit which is triggered by the processing unit 3 to alarm when the drag state is diagnosed.

[0046] In this embodiment, the second warning unit is a combination of a dashboard red warning light and a buzzer: the warning light is always on or flashing (frequency 2 Hz), and the buzzer outputs an 85 dB intermittent beep (0.5 s on / 0.5 s off).

[0047] In other embodiments, the second warning unit can be selected, for example: a pop-up warning on the central control screen (including fault wheel position code), a HUD projection of a dangerous icon (displayed on the windshield), or an external warning light (red flashing on the roof). The alarm signal is transmitted through a hard-wire or CAN bus (protocol SAE J1939 PGN 65265) to ensure that the driver can timely perceive the serious fault state.

[0048] Further, in this embodiment, the execution protection module 4 also includes a remote reporting sub-module 43 that sends fault information through wireless transmission when in the drag state.

[0049] Preferably, a vehicle-mounted 4G / 5G module (such as Yiyuan EC20) can be used to upload encrypted data packets (JSON format) to a cloud platform, including fault wheel position code, temperature value, and timestamp.

[0050] Optionally, a LoRa module can be used to transmit to a handheld terminal within 500m (in a closed mine scene); a satellite communication module (Iridium) covers signal-free areas; or through a Bluetooth gateway to a mobile phone APP. Data encryption uses the AES-256 algorithm, and supports FOTA remote diagnosis protocol updates.

[0051] Embodiment 2

[0052] In this embodiment, compared to Embodiment 1, the vehicle EPB system is taken as an example of handling the drag fault of the left rear wheel.

[0053] In this embodiment, the monitoring components are deployed as follows: 1. Temperature sensing unit installation An infrared sensor (model: TI TMP006) with a working temperature range of -40℃~500℃ is selected and installed inside the mud-proof baffle of the brake caliper shell, with the sensor detection surface facing the friction surface of the brake disc, and the vertical distance being kept at 8mm. This position can effectively isolate mud splashing while ensuring the accuracy of thermal radiation detection.

[0054] 2. Wheel speed signal acquisition configuration A magneto-electric wheel speed sensor (model: Bosch 0265001029) is fixed to the hub bearing seat with a 0.7mm±0.1mm gap adjustment with the tooth ring. The signal line is connected to the control unit using a twisted shielded cable to suppress electromagnetic interference.

[0055] Real-time diagnosis process The control unit (based on NXP S32K144 chip) performs multi-level fault diagnosis: 1) Wheel speed difference dynamic monitoring Based on the wheel speed signal, the left rear wheel speed n 左后 and the speed difference of the right rear wheel speed n 右后 is calculated in real time: Δn=∣n 左后 -n 右后 ∣ When the vehicle is driving straight (steering wheel angle < 5°) and Δn>10%* n 基准 for 5 seconds, it is determined that the wheel speed is abnormal.

[0056] Note: n 基准 Take the average speed of the coaxial two wheels 2) Temperature threshold determination Dynamic setting of temperature threshold: Tthreshold=Tenvironment+100℃ If the left rear wheel temperature exceeds the threshold for 3 seconds, the temperature abnormality flag is triggered.

[0057] 3) Current auxiliary diagnosis Through the serial Hall sensor (ACS712), the electromagnetic valve driving current waveform is collected, and when the current amplitude continuously exceeds the standard release waveform for 500ms, a first warning signal is generated.

[0058] Protection mechanism execution When the speed difference and temperature abnormalities are triggered at the same time, the system starts three-level protection: 1) Braking force release The control unit drives the high-power relay (Omron G5V-1) to attract, and its normally open contact is connected in parallel to the EPB controller output. This hardware bypass design ensures that the 12V voltage directly drives the electromagnetic valve, completely releasing the brake clamping force.

[0059] 2) Power limit control Send J1939 protocol data frame through CAN bus: PGN: 0x00F00400 Data field: torque limit value 50% + fault code 0xE1 The engine ECU executes torque output limit within 50ms.

[0060] 3) Remote state reporting 4G communication module (Quectel EC21) uploads encrypted fault data packet to cloud management platform, data format example: json json {"wheel position": "RL", "temperature": 287, "timestamp": "2023-08-28T14:22:05Z"} 4) Human-machine interaction feedback The system implements a progressive alarm strategy (as shown in Table 1): Table 1 provides a progressive alarm strategy

[0061] Example verification data After 3000 kilometers of real vehicle testing verification: 1. Diagnosis accuracy Straight-line working condition fault recognition rate: 99.2% Turn working condition false alarm rate: 0% 2. Response timeliness Average delay in action stage: 2.8s for fault diagnosis, 120ms for brake release, and 50ms for engine torque reduction 3. Safety redundancy When the control unit fails, the hardware comparator can independently trigger the buzzer alarm During network interruption, fault data is automatically stored on the SD card (retransmitted after recovery) Example 3

[0062] As Figure 2 shown, an embodiment of the present application also provides a vehicle EPB system control method, which includes the following steps: S1, obtain each brake temperature signal and the wheel speed signal of the two coaxial wheels; S2, calculate the speed difference of the two coaxial wheels based on the wheel speed signal, and determine whether the speed difference exceeds a first threshold value when the vehicle is in a straight-line driving state, and monitor whether the brake temperature exceeds a second threshold value based on the temperature signal; S3, when the speed difference is greater than the first threshold value and the temperature exceeds the second threshold value, generate a forced release instruction to directly drive the EPB electromagnetic valve 1 to release the brake, and send a power limiting request signal to the engine.

[0063] Example 4 As Figure 3 shown, compared with example 3, the engine power limiting request signal is sent through the vehicle CAN bus, and the specific execution is as follows: Protocol packaging: SAE J1939 standard protocol (PGN 0x00F00400) is used, the data field contains torque limit value (range 0-100%, accuracy ±2%) and fault priority identifier (such as 0xE1 represents emergency torque limiting); Transmission mechanism: signals are sent by the control unit CAN transceiver (such as NXP TJA1145), transmission rate 500kbps, repeated every 100ms until receiving ECU response; ECU interaction: engine ECU receives instructions based on ID filtering, executes torque limitation (such as limiting to 50% output) within 50ms, and feedbacks execution status through ACK frame.

[0064] In this embodiment, after sending the power limit request signal, the wireless transmission module starts to report fault information: Transmission method: use 4G / 5G module (such as Quectel EC25) or satellite communication terminal (Iridium 9602), push encrypted data packet to remote management platform through MQTT protocol; Data content: JSON format encapsulates stall state information, including: json { "Wheel position": "RL", / / Fault wheel position code "Temperature": 215, / / Brake peak temperature (℃) "Torque limit value": 50, / / Executed torque limit percentage "Timestamp": "2023-08-28T14:22:05Z" } Security mechanism: AES-256 encrypted transmission, data is cached to SD card (capacity 32GB) when network is disconnected, and data is automatically supplemented when network is restored.

[0065] In this embodiment, the acquisition of the EPB electromagnetic valve 1 drive current waveform can be achieved by a Hall current sensor (such as ACS712), which is installed in series with the positive electrode of the electromagnetic valve power supply line.

[0066] Technical points include: Signal sampling: 1kHz sampling rate to capture current waveform, 100Hz low-pass filter to eliminate high-frequency interference; Standard waveform comparison: prestore standard release current waveform (amplitude 2.5A±0.2A, duration 300ms), real-time detect current amplitude whether > standard value for more than 500ms set time; Fault determination: mark abnormal when current exceeds 500ms.

[0067] In this embodiment, when the vehicle is in straight driving state, it is judged whether the speed difference exceeds the first threshold value, and based on the temperature signal, it is also judged whether the brake temperature exceeds the second threshold value: Collecting the EPB solenoid 1 drive current waveform, judging whether the amplitude is continuously greater than the amplitude of the predetermined standard release current waveform for more than a set time length; when the rotational speed difference is greater than a third threshold value or the current amplitude continuously exceeds the standard, triggering the first warning unit to give a warning; wherein the third threshold value is less than the first threshold value.

[0068] In this example, the alarm is given in a hierarchical alarm manner, and the hierarchical alarm triggering logic is as follows: First-level warning trigger: When any of the following conditions is met, the dashboard yellow indicator light flashes (2Hz): The coaxial wheel speed difference is continuously greater than the third threshold value (the third threshold value is set to be 70% of the first threshold value, such as 70rpm); The current amplitude continuously exceeds the standard for 500ms.

[0069] Second-level alarm trigger: Only when the processing unit 3 confirms the drag state (wheel speed difference > first threshold value and temperature > second threshold value), the red indicator light is constantly on + the buzzer 85dB intermittently sounds, and the central control screen synchronously displays the fault wheel position code.

[0070] In summary, the embodiments of the present application achieve the following technical effects: First, accurate monitoring with low false alarm rate: using temperature and wheel speed difference fusion judgment as the core, overcoming the limitations of single sensor monitoring (such as normal temperature rise on a slope and normal wheel speed difference on a curve), greatly improving the accuracy and reliability of diagnosis.

[0071] Second, active safety and hierarchical protection: changing the traditional passive waiting discovery mode, providing a complete safety closed loop from "warning" to "alarm" to "active intervention". Especially the protection mechanism of forced release and power limiting linkage can fundamentally remove the fault source and control the consequences of accidents, which is safer.

[0072] Third, function integration and low cost: making full use of existing vehicle sensors (such as ABS wheel speed sensor and CAN bus network), the main cost of new hardware is the temperature sensor and the processing unit 3, which is easy to industrialize and promote.

[0073] Fourth, high degree of intelligence: with functions such as fault data recording and adaptive learning, providing data support for vehicle maintenance and fault analysis.

[0074] Obviously, the above-described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0075] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of the exemplary embodiments of this application is limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Also, unless otherwise indicated herein, the materials described herein can be used in a variety of applications.

[0076] It should be noted that the terms "first", "second", and the like, as used herein, are intended to modify any one of the identified objects, but do not imply a specific order or sequence, unless otherwise specifically indicated. It is to be understood that the use of the term "about" in describing the embodiments of this application is intended to convey that the description is an approximation, and that the embodiments of this application are not limited to the precise values, ranges, or parameters described, unless otherwise specifically indicated.

[0077] The preferred embodiments of the application are described above in detail. The application is not limited to the embodiments described above, but can vary and be modified, as can occur to those skilled in the art. Any equivalent realizations, modifications, and improvements made without departing from the spirit and principles of the application shall fall within the scope of protection of the application.

Claims

1. A vehicle EPB system, the vehicle comprising a plurality of wheels and brakes, each brake corresponding to one wheel, characterized in that, include: EPB solenoid valve is used to convert electrical control signals into pneumatic actions to control the clamping or releasing of the brake. The signal acquisition module is used to acquire the temperature signals of each brake and the wheel speed signals of each wheel; The processing unit is used to calculate the speed difference between two wheels on the same axle based on the wheel speed signal, and to determine whether the speed difference exceeds a first threshold when the vehicle is in a straight-line driving state, and to monitor whether the brake temperature exceeds a second threshold based on the temperature signal. When the speed difference is greater than the first threshold and the temperature exceeds the second threshold, the EPB system is determined to be in a drag state. The protection module includes an active release submodule and a power limit request submodule. In the dragged state, the active release submodule drives the EPB solenoid valve to release the brake, and sends a power limit request signal to the vehicle's engine through the power limit request submodule to reduce the output torque.

2. The vehicle EPB system according to claim 1, characterized in that, The power limit request submodule sends a power limit request signal to the engine via the vehicle CAN bus.

3. The vehicle EPB system according to claim 1, characterized in that, The active release submodule generates a forced release command to directly drive the EPB solenoid valve to release the brake.

4. The vehicle EPB system according to claim 1, characterized in that, The signal acquisition module includes multiple temperature sensing units, each temperature sensing unit corresponding to a brake to acquire the temperature signal of the brake.

5. The vehicle EPB system according to claim 1, characterized in that, The signal acquisition module includes multiple wheel speed sensing units, each of which is set up for a wheel and used to acquire the wheel speed signal.

6. The vehicle EPB system according to claim 1, characterized in that, Also includes: An alarm notification module is provided, comprising a first warning unit and a signal acquisition module comprising a current sensing unit for acquiring the drive current waveform of the EPB solenoid valve. A processing unit is used to determine whether the amplitude of the drive current waveform is continuously greater than the amplitude of a predetermined standard release current waveform for a set duration. If the speed difference is greater than a third threshold or the amplitude of the drive current waveform is continuously greater than the amplitude of the predetermined standard release current waveform for a set duration, the first warning unit is triggered to issue a warning, wherein the third threshold is less than the first threshold.

7. The vehicle EPB system according to claim 6, characterized in that, The alarm notification module also includes a second warning unit. When the EPB system is in a sluggish state, the processing unit triggers the second warning unit to issue a warning.

8. The vehicle EPB system according to claim 1, characterized in that, The execution protection module also includes a remote reporting submodule, which is used to send the lag status information wirelessly when the EPB system is in a sluggish state.

9. A vehicle EPB system control method, characterized in that, Includes the following steps: Acquire the temperature signals of each brake and the wheel speed signals of the two wheels on the same axle; The speed difference between two wheels on the same axle is calculated based on the wheel speed signal, and it is determined whether the speed difference exceeds the first threshold when the vehicle is in a straight driving state. At the same time, the brake temperature is monitored based on the temperature signal to see if it exceeds the second threshold. When the speed difference is greater than the first threshold and the temperature exceeds the second threshold, a forced release command is generated to directly drive the EPB solenoid valve to release the brake and send a power limit request signal to the engine.

10. The vehicle EPB system control method according to claim 9, characterized in that, Sending a power limit request signal to the engine includes: sending the power limit request signal to the engine ECU via the vehicle CAN bus; and after sending the power limit request signal, reporting the drag status information to the remote management platform via wireless transmission.

11. The vehicle EPB system control method according to claim 9, characterized in that, The phrase "determining whether the speed difference exceeds a first threshold when the vehicle is traveling in a straight line, and simultaneously monitoring whether the brake temperature exceeds a second threshold based on a temperature signal" is followed by: Collect the drive current waveform of the EPB solenoid valve and determine whether its amplitude is continuously greater than the amplitude of the predetermined standard release current waveform for a set duration. When the speed difference is greater than the third threshold or the amplitude is continuously greater than the amplitude of the predetermined standard release current waveform for a set duration, the first warning unit is triggered to issue a warning; wherein, the third threshold is less than the first threshold; The phrase "when the speed difference is greater than the first threshold and the temperature exceeds the second threshold" also includes: triggering the second warning unit alarm.

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