Parking Brake Valve Diagnostics Using Dual-Pressure Comparison
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Solution Overview
Problem
Conventional methods for testing secondary controllers in electronic braking systems are unreliable, particularly for autonomous vehicles, as they rely on audible signals or limited electrical measurements, and are not suitable for vehicles with simple solenoid valves.
Innovation Solution
A brake control system with a fluid circuit that includes a parking brake valve module, double check valves, and pressure sensors, allowing the secondary controller to test the parking brake function by comparing fluid pressures and generating alerts when conditions are not met, without relying on audible signals or additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional testing methods using audible signals are employed, then the testing can be performed with existing components, but the reliability of the test is poor due to dependence on human hearing ability and ambient noise
Solution Approach 1:
The patent replaces the acoustic testing method with an electrical measurement system. Instead of listening to audible signals, the system uses electrical sensors and control circuits to detect and evaluate the test signals, transforming the testing from a mechanical/acoustic process to an electrical one that is more reliable and suitable for autonomous vehicles
Solution Approach 2:
The patent introduces an intermediary electrical signal measurement system between the test signal generation and the evaluation process. Rather than directly observing audible signals, the system uses electrical measurements as an intermediary to indirectly assess the functionality of the secondary controller and fluid circuit components
2Reliability
If additional components are added to capture and evaluate test signals, then the testing reliability improves, but the device complexity and cost increase
Solution Approach 1:
The patent makes the existing electrical components of the electronic braking system serve dual functions: their primary function during normal operation and their secondary function for testing. The electrical control signals and measurement circuits used for normal brake control are also utilized for testing the secondary controller, eliminating the need for separate dedicated test components
Solution Approach 2:
The system uses its own existing electrical infrastructure to perform self-testing. The electronic braking system's inherent electrical components and control circuits are employed to generate, detect, and evaluate test signals, allowing the system to test itself without requiring external or additional specialized testing equipment
3Speed
If electrical control signals are used instead of pneumatic signals, then the response time and control accuracy improve, but the system complexity increases
Solution Approach 1:
The patent combines the testing function with the existing electrical control system. Rather than adding a separate testing mechanism, the electrical control signals already present in the electronic braking system are utilized for both normal operation and testing purposes, merging multiple functions into the existing electrical infrastructure
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 system provides reliable testing of secondary controllers and components, ensuring functionality in the event of primary controller failure, without requiring additional components or modifications, and is applicable to autonomous vehicles.
Implementation Method 1
a pressure sensor that generates a pressure signal in response to the fluid pressure
Implementation Method 2
a first solenoid valve having a supply port in communication with the first fluid source, a delivery port in fluid communication with the parking brake valve module, and an exhaust port. The first solenoid valve is biased to a first state
Data Source
AI summary
A brake control system for a vehicle includes primary and secondary controllers that control components of a fluid circuit. The fluid circuit includes a parking brake valve module and two solenoid valves controlling fluid flow to the module from two fluid sources. A double check valve in the module passes the greater fluid pressure which is measured by a pressure sensor. The secondary controller performs, prior to any failure of the primary controller, a diagnostic test. The secondary controller receives signals indicative of fluid pressure in each fluid source and the module. When the fluid pressures of the fluid sources differ, the secondary controller blocks the valve coupled to the higher pressure fluid source, compares the measured fluid pressures in the module and one of the fluid sources and, depending on the results of the comparison, generates an alert regarding the valve coupled to the lower pressure fluid source.