Electronic Parking Brake Automatic Release via Clutch Torque Calculation
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Solution Overview
Problem
The existing electronic parking brake (EPB) systems for motor vehicles face challenges in determining the conditions for automatic release, leading to potential safety hazards such as slipping or engine flame-out, and require additional sensors like clutch and gear position sensors, increasing costs and reducing clutch lifespan.
Innovation Solution
An EPB system that uses engine rotate speed and effective torque signals without a clutch position sensor, employing a controller with a CAN interface module to determine conditions for brake release based on calculated torque, engine speed, clutch pedal, and wheel speed, allowing for automatic parking and starting without additional sensor installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors (clutch position sensor and gear position sensor) are added to determine brake release conditions, then the accuracy of judging driving intention is improved, but the system cost increases and the structural complexity increases
Solution Approach 1:
The existing engine control unit is made to perform multiple functions: not only engine control but also clutch torque calculation and brake release condition judgment. This eliminates the need for separate sensors and control units, reducing system complexity while maintaining measurement accuracy through multi-functional integration
Solution Approach 2:
The patent introduces a torque calculation unit that calculates clutch torque as an intermediary parameter. Instead of directly sensing clutch position, the system uses engine rotate speed and effective torque signals to compute clutch torque, which then serves as the basis for determining brake release conditions, avoiding the need for additional position sensors
2Reliability
If clutch position sensor is added to accurately detect clutch engagement, then the reliability of automatic brake release is improved, but the manufacturing cost increases
Solution Approach 1:
The system uses signals already available from the engine control unit (engine rotate speed and effective torque) to calculate clutch torque and determine brake release conditions. The existing sensors serve multiple purposes, and the system self-determines clutch engagement status without requiring additional dedicated sensors, thereby reducing manufacturing costs while maintaining reliability
Solution Approach 2:
Instead of measuring clutch position directly with a position sensor, the system changes the measurement parameter to clutch torque, which is calculated from engine rotate speed and effective torque. This parameter transformation allows the use of existing sensors for a new measurement purpose, avoiding additional sensor costs while improving reliability through torque-based detection
3Manufacturing precision
If the driver manually operates the parking brake pull rod during starting, then the control precision of brake release timing is improved, but the ease of operation deteriorates
Solution Approach 1:
The system continuously monitors engine rotate speed and effective torque signals, calculates clutch torque in real-time, and uses this feedback to automatically determine the optimal brake release moment. This closed-loop feedback mechanism replaces manual driver judgment with automated sensor-based detection, maintaining precision while improving ease of operation
Solution Approach 2:
The patent replaces the mechanical manual operation of the parking brake pull rod with an automated electronic control system. The electronic system uses sensor signals and torque calculation to automatically control brake release timing, substituting mechanical manual control with electronic automation, thereby improving ease of operation while maintaining control precision
Data Source
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AI summary
An electronic parking brake system and assistant starting method thereof for a motor vehicle are provided, wherein, the electronic parking brake system receives all sensor signals and detection signals of the motor vehicle; when any one of the following conditions is satisfied, the brake will be released to assist the driver in starting: condition (1): a torque Tc transmitted by a clutch is calculated, and the calculated torque Tc transmitted by the clutch is greater than a torque needed for starting the motor vehicle; condition (2): an engine rotate speed is greater than an engine idle speed, and an accelerator pedal and a clutch pedal are depressed simultaneously; condition (3): starting trend of the motor vehicle is detected; condition (4): the detected engine rotate speed is lower than a first predetermined threshold value calculated according to a throttle opening data; condition (5): a detected rotate speed or angle of driving wheel is greater than a predetermined threshold value of rotate speed or angle. In the application of the electronic parking brake system and assistant starting method thereof for a motor vehicle, there is no need to additionally a mount clutch position sensor and a gear position sensor; according to all the available sensor signals and detection signals on the motor vehicle, the system can accurately judge whether the brake can be automatically released, and there is no need to modify the existing motor vehicle, featuring low lost and accurate judgment.