Automated Parking Brake Hydraulic Pressure Locking
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Solution Overview
Problem
Existing methods for operating an automated parking brake in vehicles face challenges in minimizing energy consumption and preventing brake pedal sagging due to the superposition of hydraulic and electromechanical force components, which leads to increased energy consumption and undesirable feedback for the user.
Innovation Solution
The method involves setting and locking defined hydraulic pressure levels using a valve during parking brake operations, allowing the combination of hydraulic and electromechanical force components to produce a total clamping force, with the hydraulic pressure being maintained by self-locking mechanisms, and decoupling the front and rear axle hydraulic circuits to reduce unnecessary activation and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pressure is built up first and then brake is applied electromechanically, then the total clamping force is achieved, but it cannot be ensured that the measured brake pressure is actually effective at the rear axle
Solution Approach 1:
A pressure sensor is installed at the rear axle to directly measure the hydraulic pressure at the point of application. This intermediary measurement point provides reliable feedback on whether the hydraulic pressure is actually effective where needed, resolving the uncertainty about pressure transmission from the master cylinder to the rear brake calipers.
2Force
If superposition of hydraulic and electromechanical force components is performed during clamping process, then the required total clamping force is achieved, but the energy consumption of the hydraulic actuating unit increases
Solution Approach 1:
The hydraulic actuator builds up the required pressure in advance before the electromechanical actuator engages. This preliminary hydraulic pressure buildup reduces the workload on the electromechanical actuator during the actual clamping phase, thereby reducing overall energy consumption while still achieving the required total clamping force through superposition.
Solution Approach 2:
The system alternates between hydraulic and electromechanical actuation in periodic phases. The hydraulic actuator operates in discrete pressure buildup phases followed by holding phases where the electromechanical actuator takes over, reducing continuous hydraulic energy consumption while maintaining the required clamping force through coordinated superposition.
3Force
If large volume is displaced during clamping force buildup, then the required clamping force is achieved, but severe sagging of the brake pedal occurs
Solution Approach 1:
The hydraulic actuator performs preliminary pressure buildup in controlled increments before full clamping force is required. This staged approach allows the system to achieve the necessary pressure without requiring a single large-volume displacement that would cause severe pedal sagging, improving ease of operation while maintaining force effectiveness.
Solution Approach 2:
The clamping force buildup is performed in periodic cycles with alternating hydraulic and electromechanical phases. This periodic action divides the total volume displacement into smaller incremental steps, preventing severe brake pedal sagging while still achieving the required total clamping force through cumulative superposition of both actuation methods.
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 approach reduces the total energy consumption of the brake application process and minimizes brake pedal sagging, providing a more efficient and comfortable user experience while maintaining safety and compliance with legal requirements.
Implementation Method 1
a hydraulic actuator for producing a hydraulic force component
Implementation Method 2
an electromechanical actuator for producing an electromechanical force component
Implementation Method 3
the defined hydraulic pressure level is locked in by means of a valve when said pressure level is reached
Implementation Method 4
the total clamping force is maintained by self locking of the parking brake
Data Source
AI summary
A method for operating an automated parking brake in a motor vehicle, having a hydraulic actuator for producing a hydraulic force component and an electromechanical actuator for producing an electromechanical force component, includes superimposing the hydraulic force component and the electromechanical force component to obtain a total clamping force for a parking brake operation, and maintaining the total clamping force by self-locking of the parking brake. The method further comprises during the parking brake operation, setting at least one defined hydraulic pressure level using the hydraulic actuator, and locking-in a defined hydraulic pressure level with a valve when the at least one defined hydraulic pressure level is reached.