Brake Stroke Sensor Abnormality Detection via Master Cylinder Pressure
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Solution Overview
Problem
Existing brake control systems face challenges in accurately determining stroke sensor abnormalities, which can lead to inaccurate braking control and a poor brake feeling due to issues like abrasion powder affecting the relationship between brake pedal stroke and detected electric signals.
Innovation Solution
A stroke sensor abnormality determining apparatus that calculates a total target value for vehicle deceleration using both stroke sensor and master cylinder pressure signals, and only outputs an abnormality signal if the change in the total target value exceeds a predetermined threshold, thereby minimizing unnecessary braking control changes and improving brake feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stroke sensor abnormality determining apparatus performs abnormality detection based on stroke sensor signals, then the reliability of braking control is improved, but the brake feeling deteriorates due to unnecessary control mode changes
Solution Approach 1:
The patent introduces a master cylinder pressure sensor as an intermediary element to verify stroke sensor abnormalities. Instead of relying solely on stroke sensor data, the system uses pressure sensor readings as a mediator to confirm whether detected abnormalities are genuine. This dual-verification approach prevents false abnormality detections caused by abrasion powder interference, thereby maintaining reliable braking control while avoiding unnecessary control mode changes that would degrade brake feeling.
2Measurement precision
If the stroke sensor abnormality determination is performed continuously, then the measurement precision of sensor abnormality is improved, but the frequency of unnecessary abnormality signals increases due to abrasion powder interference
Solution Approach 1:
The patent implements a feedback mechanism where the abnormality determining unit continuously monitors both stroke sensor and master cylinder pressure sensor signals, compares their consistency, and adjusts abnormality determination accordingly. When the pressure sensor data confirms normal operation despite stroke sensor anomalies, the system feedback-prevents false abnormality signals. This feedback-based verification reduces unnecessary abnormality detections while maintaining precise detection of genuine sensor failures.
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 approach reduces the frequency of braking control mode changes and enhances brake feeling by accurately determining when a stroke sensor abnormality is significant enough to affect braking control, ensuring precise and smooth braking operations.
Implementation Method 1
a stroke sensor configured to detect a stroke of a brake pedal by detecting an electric signal that varies in response to the stroke of the brake pedal
Data Source
AI summary
A stroke sensor abnormality determining apparatus includes a stroke sensor for detecting a stroke of a brake pedal by detecting an electric signal that varies in response to the stroke of the brake pedal, a deceleration calculating unit for calculating a total target value, which is correlated with a target deceleration of a vehicle, based on at least the stroke, and an abnormality determining unit for determining whether or not an abnormality of the stroke sensor occurs, based on the electric signal detected by the stroke sensor, the abnormality determining unit being configured so that a signal indicating the abnormality of the stroke sensor can be outputted when the abnormality is determined to have occurred in the stroke sensor.