Electropneumatic Brake Controller Bistability via Three 2/2-Way Valves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electropneumatic brake control systems for heavy commercial vehicles face challenges in implementing bistable behavior for parking brakes efficiently and cost-effectively, with previous solutions requiring expensive solenoid valves and complex configurations prone to failure.
Innovation Solution
The system employs three 2/2-way solenoid valves to achieve bistability, using two solenoid valves in a blocking position when de-energized and a third solenoid valve for feedback, allowing for a simpler, cost-effective design that reduces part count and susceptibility to failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive bistable solenoid valves are used to ensure stable parking brake operation, then reliability is improved, but cost increases and device complexity increases
Solution Approach 1:
The patent divides the single complex bistable solenoid valve function into multiple simpler 2/2-way solenoid valves (first, second, and third solenoid valves) that work together in a segmented manner. Each valve handles a specific aspect of the bistable control, reducing individual valve complexity while maintaining overall system reliability through their coordinated operation.
Solution Approach 2:
The relay valve serves multiple functions: it acts as a feedback element that detects the actual brake cylinder pressure state and uses this feedback to maintain bistability. The relay valve simultaneously controls pressure supply and venting based on feedback from the brake cylinder, making it a multi-functional component that reduces the need for separate dedicated valves for each function.
2Reliability
If redundant systems are implemented to prevent valve failure, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism where the relay valve continuously monitors the actual pressure state in the brake cylinder and uses this information to maintain the desired bistable state. This feedback loop allows the system to detect and correct deviations automatically, providing inherent fault tolerance without requiring separate redundant valve systems.
Solution Approach 2:
The system design anticipates potential failures by incorporating the relay valve feedback mechanism that can detect and compensate for pressure deviations before they lead to complete system failure. The feedback system prepares the system to handle unexpected states by automatically adjusting valve positions to maintain bistability, cushioning against potential failure modes.
3Reliability
If 3/2 solenoid valves are used for feedback control, then bistability is achieved, but cost increases and the system cannot adjust to intermediate pressure values
Solution Approach 1:
The patent transitions from static 3/2-way valves to dynamic 2/2-way valves that can be rapidly switched between open and closed states. This dynamic switching capability, controlled by the electronic control unit based on relay valve feedback, allows the system to achieve bistability while maintaining the flexibility to adjust pressure levels dynamically, including intermediate values during transition phases.
Solution Approach 2:
The patent replaces the purely mechanical 3/2-way valve feedback system with an electronically controlled 2/2-way valve system. This substitution allows for more precise control and adaptability, as the electronic control unit can process relay valve feedback signals and adjust valve actuation accordingly, enabling both bistable operation and intermediate pressure adjustment capabilities.
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 configuration provides a robust, cost-effective, and reliable electropneumatic brake control system with improved bistability, reducing the need for redundant systems and minimizing the risk of failure under high accelerations.
Implementation Method 1
The first solenoid valve device (8) is formed by three 2/2-way solenoid valves (10, 12, 30)... each solenoid valve being switchable between an open position and a blocked position
Implementation Method 2
a relay valve (18), the pneumatic control input (20) of which is connected on the one hand to the first solenoid valve device (8) and on the other hand to the connection (40) for the at least one spring-actuated brake cylinder
Implementation Method 3
spring-loaded brake cylinders which, in the released position, apply compressed air to a spring compression chamber and thus keep the spring tensioned, while the spring compression chamber is vented for braking
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an electropneumatic brake controller (1) for controlling a parking brake which includes at least one spring brake cylinder, comprising a connection (40) for the at least one spring brake cylinder; a first solenoid valve device (8) which can be controlled by means of an electronic controller (14); a relay valve (18), the pneumatic control inlet (20) of which is connected to the first solenoid valve device (8) and to the connection (40) for the at least one spring brake cylinder and the working outlet (28) of which is connected to the connection (40) for the at least one spring brake cylinder; an electric parking brake signal connection (32) which is connected to the electronic controller (14) for an electric parking brake signal generator (36) and via which parking brake signals can be transmitted into the controller (14); and a supply connection (2) which is secured by a non-return valve (4) for at least one compressed air supply, said supply connection being connected to the first solenoid valve device (8) and to a supply inlet (16) of the relay valve (18). According to the invention, the first solenoid valve device (8) is made of three 2/2 way solenoid valves (10, 12, 30), each of which has a blocking position and a passage position. A first 2/2 way solenoid valve (10), in the form of an inlet valve, is connected between the control inlet (20) of the relay valve (18) and the supply connection (2), a second 2/2 way solenoid valve (12) is connected between the control inlet (20) of the relay valve (18) and a pressure sink (24), and a third 2/2 way solenoid valve (30) is arranged between the working outlet (28) and the control inlet (20) of the relay valve (18).