Pneumatic Park Brake Backup Valve Isolation for ECU Failure
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Solution Overview
Problem
Existing electronically controlled pneumatic parking brake systems in vehicles fail to ensure proper functioning of the parking brake when the electronic control unit (ECU) is defective or when a safety function is triggered, particularly in driverless and remotely driven vehicles.
Innovation Solution
The system incorporates a backup pneumatic park brake valve controlled by a third solenoid valve piloted by a second ECU, along with a fourth solenoid valve that isolates the control line from the backup valve when the primary ECU is operational, ensuring the parking brake can be actuated even if the primary ECU fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an electronic control unit (ECU) is used to control the parking brake system, then the parking brake function can be automated and controlled electronically, but the system becomes vulnerable to ECU failure or electrical power supply failure
Solution Approach 1:
The control system is divided into two independent ECUs (first ECU and second ECU) that can independently control the parking brake system. This segmentation ensures that if one ECU fails, the other can still operate the parking brake, thereby maintaining system reliability while preserving electronic automation.
Solution Approach 2:
The system incorporates a backup pneumatic park brake valve that is activated in advance preparation for potential ECU failure. This backup component is designed to automatically engage if the primary electronic control fails, providing a safety cushion that prevents complete system failure and ensures the parking brake function remains reliable.
2Reliability
If a backup pneumatic park brake valve is added to the system, then the system reliability is improved in case of ECU failure, but the device complexity increases
Solution Approach 1:
A fourth solenoid valve is introduced as an intermediary component that selectively connects or isolates the control line from the backup pneumatic park brake valve based on the operational status of the first ECU. This intermediary valve manages the interaction between the primary and backup systems, enabling reliable parking brake function while minimizing the complexity impact through intelligent connection management.
3Productivity
If the fourth solenoid valve isolates the control line from the backup valve when the first ECU is operational, then the system operates efficiently using the primary control, but the backup system remains active and could potentially interfere
Solution Approach 1:
The fourth solenoid valve extracts or removes the backup pneumatic park brake valve from the active control path when the first ECU is operational. By isolating the backup valve through this extraction mechanism, the system ensures that only the primary control system actively manages the parking brake, eliminating potential interference while maintaining the backup system's availability for emergency use.
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 ensures the parking brake system remains operational even if the primary ECU is defective, enhancing safety and reliability, especially in driverless and remotely driven vehicles.
Implementation Method 1
The electronically controlled pneumatic parking brake system comprises a first electronic control unit, a second electronic control unit, an electronic park brake device controlled by the first electronic control unit and comprising at least one bi-stable relay valve configured for selectively feeding the at least one park brake actuator with air under pressure
Implementation Method 2
at least one bi-stable relay valve configured for selectively feeding the at least one park brake actuator with air under pressure; a source of air under pressure for feeding air under pressure to each bi-stable relay valve, via a respective supply line
Data Source
AI summary
An electronically controlled pneumatic parking brake system comprises a park brake actuator, first and second electronic control units and an electronic park brake device comprising a bi-stable relay valve selectively feeding the park brake actuator, solenoid valves for controlling the relay valve via a control line and at least one backup pneumatic park brake valve configured to take first and second configurations. The parking brake system also comprises a third solenoid valve, controlling the backup park brake valve, and a fourth solenoid valve selectively connecting the control line to the backup park brake valve. The first electronic control unit pilots the fourth solenoid valve to isolate the control line from the backup park brake valve if the third solenoid valve controls the backup park brake valve to take a second configuration when the first electronic control unit is operational.