Brake Pressure Sensor Diagnosis Using Upstream-Downstream Comparison
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake control systems with only one pressure sensor on the downstream side of shut-off valves face reduced detectability for abnormalities when employing similar detection methods.
Innovation Solution
A brake control apparatus that determines abnormalities in pressure sensors by comparing detection values from a sensor on the upstream side with a sensor on the downstream side after actuating the shut-off valve and hydraulic pressure source, improving detectability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one pressure sensor is provided on the downstream side of the shut-off valves, then the device complexity is reduced, but the detectability for abnormality in the pressure sensor deteriorates
Solution Approach 1:
The system performs preliminary abnormality detection by comparing pressure sensor readings before the shut-off valve operates, establishing a baseline relationship. This allows the system to detect sensor abnormalities in advance by identifying deviations from the expected pressure relationship, maintaining reliability without adding multiple downstream sensors.
Solution Approach 2:
The upstream pressure sensor serves as an intermediary reference point. By comparing the downstream pressure sensor reading with the upstream pressure sensor reading (which reflects the same hydraulic system state), the system can detect abnormalities in the downstream sensor without requiring multiple downstream sensors, thus reducing complexity while maintaining detectability.
2Reliability
If multiple pressure sensors are provided on the downstream side of the shut-off valves, then the detectability for abnormality in the pressure sensor is improved, but the device complexity increases
Solution Approach 1:
The system uses the upstream pressure sensor to establish a preliminary reference pressure value before valve operation. This preliminary measurement enables abnormality detection in downstream sensors by comparing against the expected pressure relationship, achieving high detectability without requiring multiple downstream sensors.
Solution Approach 2:
The upstream pressure sensor acts as an intermediary that provides a reference measurement for detecting downstream sensor abnormalities. By using this intermediary reference, the system achieves reliable abnormality detection with fewer sensors, avoiding the complexity of installing multiple downstream sensors.
3Reliability
If the shut-off valve portion is actuated to improve abnormality detection, then the detectability for pressure sensor abnormality is improved, but the response time increases
Solution Approach 1:
The system performs preliminary abnormality detection by comparing pressure readings before the shut-off valve actuates. By establishing the baseline pressure relationship in advance, the system can detect sensor abnormalities immediately without waiting for valve operation, thus improving response time while maintaining detectability.
Data Source
AI summary
An ECU determines an abnormality in a master cylinder pressure sensor or a discharge pressure sensor based on a detection value of the master cylinder pressure sensor and a detection value of the discharge pressure sensor after actuating a shut-off valve in a valve-opening direction and actuating a pump.