Parking Brake Valve Redundancy for Jammed Hydraulic Release
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Solution Overview
Problem
Existing braking systems for motor vehicles lack redundancy in control valves, leading to potential unintentional activation of the parking brake due to mechanical or electrical failures, requiring additional mechanical interfaces for deactivation, and increasing hardware and software complexity.
Innovation Solution
A braking system with a first directional control valve, a second redundancy valve, and a third brake valve, where the control and redundancy valves are biased mechanically to a closed state, and the brake valve is biased open, allowing hydraulic fluid to build deactivation pressure in the brake cylinder. An electronic control unit controls these valves to ensure pressure release in case of defects, and an electronic locking unit operates the redundancy valve to maintain functionality even when the main control unit fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy is implemented using bistable valves and redundant control units, then safety in the event of electrical failures is improved, but hardware and software complexity increases
Solution Approach 1:
The patent inverts the traditional approach by using a single control unit instead of redundant control units. The control unit is designed to detect valve jamming conditions and automatically switch to an alternative control mode, achieving redundancy through intelligent control rather than duplicate hardware components.
Solution Approach 2:
The control unit is designed with multi-functionality to perform both normal control and emergency backup control. It can detect valve jamming, switch control modes, and manage the brake system under different failure scenarios, eliminating the need for separate redundant control units while maintaining safety.
2Reliability
If redundancy is implemented using bistable valves, then safety in the event of electrical failures is improved, but the parking lock cannot be deactivated if the valve is incorrectly applied
Solution Approach 1:
The patent employs dynamic control where the control unit can adaptively switch between different control modes based on the system state. The valve system is designed to be controllable in both normal and emergency modes, allowing the parking lock to be deactivated even when one valve is jammed, by dynamically adjusting which valve is actuated.
Solution Approach 2:
The control unit continuously monitors the state of the valves and brake system, providing feedback to detect jamming conditions. Based on this feedback, the control unit can identify when a valve is incorrectly applied and switch to an alternative control strategy to deactivate the parking lock, ensuring operational flexibility.
3Reliability
If a mechanical interface is added to release pressure from the spring brake cylinders, then redundancy is improved, but hardware complexity and cost increase
Solution Approach 1:
The patent replaces the need for a mechanical interface with an electronically controlled solution. The control unit manages the release of pressure from the spring brake cylinders through electronic control of the valves, eliminating the need for additional mechanical release interfaces while maintaining redundancy through intelligent control.
4Reliability
If redundant control units are used, then safety in the event of electrical failures is improved, but costs for a second control unit and software development increase
Solution Approach 1:
The control unit is designed with multi-functionality to perform both normal control and emergency backup control. It can detect valve jamming, switch control modes, and manage the brake system under different failure scenarios, eliminating the need for separate redundant control units while maintaining safety.
Solution Approach 2:
The control unit is designed to self-monitor and self-correct by detecting valve jamming conditions and automatically switching to an alternative control mode. This self-service capability eliminates the need for additional redundant control units and associated software development 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 safe and reliable operation of the parking brake without additional mechanical interfaces, reducing hardware and software complexity, and allowing the driver to activate the parking lock even in the event of electronic control unit failure.
Implementation Method 1
a first directional control valve (6) designed as a control valve, a second directional control valve (7) designed as a redundancy valve, and a third directional control valve (10) designed as a brake valve
Implementation Method 2
A valve spool (12) of the control valve (6) and of the redundancy valve (7) is mechanically preloaded by a spring element (34.1, 34.2) in a closed switching position
Implementation Method 3
The valve spools (12) of the control valve (6) and of the redundancy valve (7) can be moved from the closed switching position to an open switching position by energizing a first electromagnet (EM1)
Implementation Method 4
a deactivation pressure must be built up within the brake cylinder
Data Source
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AI summary
The invention relates to a braking system (1) for a motor vehicle. The braking system (1) comprises a control valve (6), a redundancy valve (7), a brake valve (10), a brake cylinder (14), a pressure medium source, an electronic control unit (16), a parking lock (24), and a pressureless tank (T). The control valve (6) and the redundancy valve (7) are mechanically biased in a closed state, whereas the brake valve (10) is mechanically biased in an open state.The electronic control unit (16) is configured to control the brake valve (10) in such a way that it enters a closed state, so that hydraulic fluid from the brake cylinder (14) flows directly into the unpressurized tank (T) via the brake valve (10) and no hydraulic fluid is directed into the brake cylinder (14) via the control valve (6) or the redundancy valve (7) and the brake valve (10) if the control valve (6) or the redundancy valve (7) remains in an open state due to a mechanical defect, although it should be in the closed state.