Electric Parking Brake Hydraulic Boosting Control
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Solution Overview
Problem
Existing electric parking brake systems face challenges in ensuring safe vehicle parking, particularly under conditions of increased temperature and low operating voltage, where the desired switch-off current cannot be achieved, leading to potential safety issues and unnecessary hydraulic assistance, which compromises comfort.
Innovation Solution
A method that records the actual application force generated by the brake actuator and applies hydraulic support pressure only when the actual value is below a predetermined threshold, using a hydraulic pump controlled by the service brake function to provide low-energy hydraulic support, allowing the parking brake to be retensioned efficiently and reducing unnecessary hydraulic assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic support brake pressure is applied frequently to ensure safe parking, then parking safety is improved, but driver comfort deteriorates due to unnecessary hydraulic assistance
Solution Approach 1:
The control unit continuously monitors the actual application force of the brake actuator and compares it with the target application force. Based on this feedback, the system intelligently decides whether hydraulic support is necessary, avoiding unnecessary activation and improving driver comfort while ensuring safety when actually needed.
Solution Approach 2:
The system determines in advance whether the electric parking brake can achieve the required application force under current conditions (temperature, voltage). If the predicted application force would be insufficient, hydraulic support is pre-applied before the parking brake is activated, ensuring safety without unnecessary intervention in normal conditions.
2Force
If the electric motor is actuated to generate application force, then parking brake function is achieved, but the desired switch-off current cannot be reached under increased temperature and low operating voltage, compromising safety
Solution Approach 1:
The system monitors temperature and operating voltage parameters to predict whether the electric motor can achieve the required application force. When these parameters indicate insufficient motor performance, the system switches to hydraulic support mode, changing the actuation mechanism to ensure reliable parking brake application.
Solution Approach 2:
The hydraulic service brake acts as an intermediary to provide additional application force when the electric parking brake alone is insufficient. The hydraulic support brake pressure supplements the electric actuation, ensuring the total application force meets safety requirements under adverse conditions.
3Force
If hydraulic support brake pressure is applied before parking brake activation, then application force is ensured, but energy consumption increases due to unnecessary hydraulic pump operation
Solution Approach 1:
Instead of applying full hydraulic support pressure in all cases, the system applies hydraulic support only partially (when needed) and only to the extent necessary to supplement the electric parking brake. This avoids excessive energy consumption while ensuring sufficient application force when required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures hydraulic support is only provided when necessary, minimizing energy consumption and maintaining comfort by avoiding frequent unnecessary hydraulic assistance, while ensuring safe and efficient parking brake operation.
Implementation Method 1
a hydraulic support brake pressure corresponding to a setpoint support brake pressure which is smaller than a setpoint brake pressure is generated by means of the service brake function
Implementation Method 2
an application force generated electrically with the parking brake function changes with a force exerted on the brake actuator
Data Source
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AI summary
The invention relates to a method for hydraulically boosting an electric parking brake of a vehicle, said brake comprising at least one brake actuator (2c, 2d). Said vehicle has a hydraulic service brake function and an electric parking brake function for electrically and hydraulically actuating the at least one brake actuator (2c, 2d), wherein an application force (F) that is electrically generated by the parking brake function is superimposed on a boosting brake force that is generated by applying a hydraulic boosting brake pressure (Pu) provided by the service brake function to the brake actuator (2c, 2d). According to the invention, when the parking brake is actuated in order to generate a predetermined application force, the application force generated by the brake actuator (2c, 2d) is detected by means of a measured variable (I) representing the value of the application force as the actual value (Iist), if an actual value (Iist) of the measured value (I) is smaller than a first target value (I1, soll) representing a first target force value (F1,soll) of the application force, a hydraulic boosting brake pressure (Pu) corresponding to a predetermined target boosting brake pressure value (Pu,soll) is applied to the brake actuator (2c, 2d), and by means of the parking brake function a tension adjustment function for adjusting the tension of the brake actuator (2c, 2d) to which the hydraulic boosting brake pressure (Pu) is applied is carried out in order to achieve the predetermined application force.