Electro-Hydraulic Parking Brake Pre-Charging for Fast Release
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Solution Overview
Problem
Current electro-hydraulic parking brake systems experience a time delay between the release demand and actual release, causing confusion for drivers, particularly when using driver assistance systems.
Innovation Solution
A method that determines a vehicle status to generate a hydraulic pre-charging pressure, allowing for immediate release of the parking brake by directing pre-charging pressure to the brake upon demand, utilizing existing vehicle systems like ABS and ESP for pressure generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the pressure generating unit is activated only upon release demand, then the system remains simple and energy-efficient, but the release time is delayed causing driver confusion
Solution Approach 1:
The patent applies preliminary action by pre-charging the hydraulic system with a first hydraulic pressure before the release demand occurs. The control device determines vehicle status (such as gear position, brake application state, and driver presence) and activates the pressure generating unit in advance to build up hydraulic pressure in the first hydraulic circuit. This pre-built pressure is then immediately available when release is demanded, eliminating the delay without requiring continuous high-pressure generation, thus balancing fast response with energy efficiency.
2Loss of time
If hydraulic pressure is continuously maintained, then release is immediate, but energy consumption increases
Solution Approach 1:
The system performs preliminary action by building up hydraulic pressure only when vehicle status indicators suggest release is imminent (such as gear shift to drive position, brake application detected, or driver presence confirmed). The control device monitors these parameters and pre-charges the system conditionally, rather than maintaining continuous pressure. This selective pre-charging approach ensures fast release when needed while avoiding unnecessary energy consumption during normal parking brake engagement states.
Solution Approach 2:
The patent implements dynamics by making the hydraulic pressure state adaptive based on real-time vehicle status. The control device continuously monitors parameters such as gear position, brake application state, and driver presence to dynamically adjust whether to maintain pre-charged pressure or allow pressure to dissipate. This dynamic adjustment optimizes the balance between release speed and energy consumption according to actual operating conditions.
3Reliability
If the system uses additional components for hydraulic pressure generation, then release performance improves, but installation space and costs increase
Solution Approach 1:
The patent applies universality by making the existing brake controller's pressure generating unit perform multiple functions. The same pump and hydraulic circuit that serve the service brake system are also used to generate hydraulic pressure for parking brake release. The control device intelligently directs hydraulic fluid to either the service brakes or the parking brake release circuit based on operational demands. This multi-functional approach improves release performance without adding dedicated pressure generation components, thereby avoiding increased system complexity, installation space requirements, and costs.
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
Ensures rapid and user-friendly release of the parking brake by ensuring hydraulic pressure is immediately available upon demand, reducing the time offset and enhancing driver confidence.
Implementation Method 1
hydraulic fluid under pressure is admitted to the housing, whereby friction linings on the piston press against the brake disc
Implementation Method 2
the necessary hydraulic pressure is generated by a pump assembly
Data Source
AI summary
The disclosure relates to a method for releasing an electro-hydraulic parking brake of a motor vehicle, wherein a vehicle status is determined, in dependence on the vehicle status, a pre-charging pressure demand is determined by a control device, in the event of a pre-charging pressure demand, a hydraulic pre-charging pressure is generated by a pressure generating unit, and in the event of a parking brake release demand, the pre-charging pressure is directed to the electro-hydraulic parking brake.