Parking Brake Valve Bypass for Emergency Spring Brake Actuation
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Solution Overview
Problem
Existing electropneumatic parking brake systems face challenges in emergency application, particularly when the parking brake valve unit or control unit fails, as the non-return valve prevents compressed air from flowing back to the reservoir, making it difficult to engage the spring-loaded accumulator brake cylinders.
Innovation Solution
The introduction of a bypass valve that can be switched independently of the parking brake valve unit allows for the supply of air to and exhaustion from the spring-loaded accumulator port, enabling emergency engagement of the brake cylinders even if the primary system fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-return valve is arranged between the parking brake valve unit and the parking brake reservoir to prevent compressed air from flowing back, then the reliability of the parking brake system is improved, but the ease of operation for emergency application deteriorates
Solution Approach 1:
A bypass valve is introduced as an intermediary component between the parking brake valve unit and the parking brake reservoir. This bypass valve provides an alternative flow path that allows compressed air to flow back to the reservoir during emergency situations, overriding the non-return valve's blocking function. The bypass valve acts as a mediator that resolves the conflict between maintaining normal operational reliability (through the non-return valve) and enabling emergency application (by allowing reverse flow when needed).
2Reliability
If a bypass valve is added to allow air supply and exhaust in emergency situations, then the reliability of emergency application is improved, but the device complexity increases
Solution Approach 1:
The bypass valve is designed with multi-functionality to reduce overall system complexity. It serves multiple purposes: (1) allowing reverse flow during emergency application, (2) providing a fallback path if the main parking brake valve unit fails, and (3) enabling manual override capabilities. By consolidating these functions into a single component, the patent avoids the need for separate emergency valves, complex control systems, or additional actuators, thereby limiting the increase in device complexity while achieving improved emergency reliability.
3Adaptability or versatility
If the bypass valve is controlled independently of the parking brake valve unit, then the adaptability for fault tolerance is improved, but the device complexity increases
Solution Approach 1:
The bypass valve is designed to operate with a degree of independence from the main parking brake valve unit, providing self-service capabilities for fault tolerance. The bypass valve can be actuated by separate control signals or manual input, allowing it to function autonomously when the primary control system fails. This independent operation enhances adaptability to faults without requiring complex interlocking mechanisms or centralized control logic, as the bypass valve serves itself as a standalone safety component.
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
The bypass valve ensures that the spring-loaded accumulator brake cylinders can be engaged or released in emergency situations, enhancing the safety and reliability of the electropneumatic parking brake system by providing a redundant mechanism for air supply and exhaust.
Implementation Method 1
a non-return valve arranged between the parking brake valve unit and the parking brake reservoir in order to prevent compressed air from flowing back from the parking brake valve unit to the parking brake reservoir
Implementation Method 2
a bypass valve which can be switched to supply air to and exhaust it from the spring-loaded accumulator port
Implementation Method 3
spring-loaded accumulator brake cylinders which are applied by virtue of a spring force and are opened when air is supplied to them
Data Source
AI summary
An electropneumatic parking brake device is for supplying air to and exhausting air from spring-loaded accumulator brake cylinders of an electronically controllable pneumatic braking system for a vehicle and includes a parking brake valve unit with a reservoir port for receiving reservoir pressure from a parking brake reservoir. The parking brake valve unit sets a parking brake pressure at a spring-loaded accumulator port depending on a parking brake signal. A non-return valve is arranged between the parking brake valve unit and the parking brake reservoir to prevent compressed air from flowing back from the parking brake valve unit to the reservoir. A bypass valve is provided which can be switched to supply air to and exhaust it from the spring-loaded accumulator port. The bypass valve is activated and switched independently of the parking brake valve unit.