Brake Solenoid Valve Failure Detection by Hydraulic Pressure Feedback
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Solution Overview
Problem
Existing brake systems fail to detect mechanical failures in solenoid valves that control the opening and closing of critical flow paths, leading to issues such as incomplete braking due to stuck valves, which can compromise safety.
Innovation Solution
A method and device for determining solenoid valve failure by systematically operating backup and mixing valves to specific positions and using pressure sensors to detect mechanical failures, including close-stuck and open-stuck states, ensuring hydraulic pressure is correctly applied to wheel cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backup valve is mechanically closed and stuck due to failure, then the valve remains in a closed state, but the backup pressure cannot be transmitted
Solution Approach 1:
The system performs preliminary diagnostic actions by systematically operating valves to specific positions before normal braking operations. The control unit moves the piston to predetermined positions and operates valves in specific sequences to proactively detect potential failures of the backup valve and mixing valve, preventing undetected failure states from compromising safety.
Solution Approach 2:
The pressure sensor provides continuous feedback on hydraulic pressure conditions during valve operations. By monitoring pressure changes during systematic valve operations, the control unit receives feedback that indicates whether valves are functioning correctly or have become stuck, enabling real-time failure detection and alerting the driver through the warning device.
2Reliability
If the mixing valve is mechanically open and stuck due to failure, then the valve remains open, but the entire amount of brake oil is exhausted in a circuit leak situation
Solution Approach 1:
The brake system is segmented into distinct hydraulic circuits (front wheel circuit and rear wheel circuit) with the mixing valve controlling the connection between them. The diagnostic method segments the valve operation into specific test positions and sequences, allowing independent evaluation of each valve's functionality without requiring complete system disassembly or complex instrumentation.
Solution Approach 2:
The control unit performs preliminary diagnostic operations by systematically closing the mixing valve and operating other valves in a predetermined sequence before normal braking. This preliminary action detects potential open-stuck failures of the mixing valve by observing pressure changes during the diagnostic cycle, preventing catastrophic brake oil exhaustion.
3Reliability
If no failure detection system is implemented, then the system structure remains simple, but solenoid valve failures go undetected compromising safety
Solution Approach 1:
The brake system performs self-diagnosis by using its own existing components (control unit, pressure sensor, warning device) to detect valve failures. The control unit systematically operates the valves and monitors pressure changes using the already-present pressure sensor, eliminating the need for external diagnostic equipment or complex additional sensing systems while maintaining high safety standards.
Solution Approach 2:
The control unit serves multiple functions: it controls normal braking operations, systematically operates valves for diagnostics, interprets pressure sensor data during diagnostics, and activates the warning device. This multi-functionality allows the system to implement comprehensive failure detection without adding separate dedicated diagnostic hardware, thereby limiting the increase in device complexity.
4Measurement precision
If pressure sensors are used to detect valve failures, then failure detection precision is improved, but the device complexity increases
Solution Approach 1:
The system uses the existing pressure sensor readings as a proxy or copy of valve functionality. Instead of directly measuring valve position or mechanical state, the system infers valve health from pressure changes during systematic operations, creating a functional copy of valve status information from pressure data. This approach maintains high detection precision while avoiding the need for additional direct valve sensors.
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
Enables reliable detection of solenoid valve failures, ensuring proper brake function and driver safety by identifying and alerting the driver to potential valve malfunctions.
Implementation Method 1
determining whether the backup valve is in a failure state using a pressure sensor
Implementation Method 2
a master cylinder connected to the pedal cylinder and including a piston moving forward and backward by driving of the motor, the master cylinder generating a braking hydraulic pressure using the piston
Implementation Method 3
a motor driven by an electrical signal output corresponding to or indicative of displacement of the brake pedal
Data Source
AI summary
According to at least one embodiment, the present disclosure provides a method for determining failure of a solenoid valve in a brake system, the method comprising: a first valve operation process of opening a backup valve that controls opening and closing of a flow path disposed between a master cylinder and a pedal cylinder and opening and closing a plurality of valves other than the backup valve in a preset manner; a first determination process of moving a piston disposed in a master cylinder to a preset first position and determining whether the backup valve is in a failure state using a pressure sensor; a second valve operation process of closing a mixing valve that controls opening and closing of a flow path disposed between a front wheel circuit and a rear wheel circuit, and opening and closing the plurality of valves other than the mixing valve in a preset manner; and a second determination process of moving the piston disposed in the master cylinder to a preset second position and determining whether the mixing valve is in a failure state using a pressure sensor.