Vehicle Brake Control Circuit Sensor Abnormality Detection
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Solution Overview
Problem
The existing brake control systems for vehicles face reliability issues due to the shared use of a single hydraulic-pressure sensor for controlling both master-cylinder and wheel-cylinder pressures, making it difficult to ensure accurate and reliable control, especially when sensor abnormalities occur.
Innovation Solution
A vehicle control apparatus with separate control circuits that communicate through a signal line to detect sensor abnormalities, where the second control circuit determines sensor issues based on a predetermined criterion and the first control circuit verifies these determinations using a different criterion, ensuring timely and accurate detection of sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single hydraulic-pressure sensor is shared between the first control circuit and the second control circuit, then the number of sensors is reduced, but the reliability of control is compromised when sensor abnormalities occur
Solution Approach 1:
The patent divides the control system into two independent control circuits (first control circuit for master-cylinder pressure control and second control circuit for wheel-cylinder pressure control), each capable of independently detecting sensor abnormalities using different criteria. This segmentation allows the system to maintain reliability even when one control circuit detects an abnormality, as the other circuit can continue normal operation with a different detection threshold.
2Device complexity
If the first control circuit uses the detection signal for both master-cylinder pressure control and wheel-cylinder pressure control, then device complexity is reduced, but the ability to ensure control reliability deteriorates
Solution Approach 1:
The patent employs different abnormality determination criteria (different threshold values or determination rules) in the first control circuit and the second control circuit. When the hydraulic-pressure sensor provides a detection signal, each control circuit evaluates it against its own specific criteria. This parameter differentiation enables independent abnormality detection, allowing the system to identify sensor failures more reliably without increasing overall device complexity.
Data Source
AI summary
A second ECU determines whether or not there is an abnormality in a hydraulic-pressure sensor in a first cycle based on a detection value of the hydraulic-pressure sensor, and outputs a signal indicating a determination of an occurrence of the abnormality to a first ECU via a signal line when determining the occurrence of the abnormality in the hydraulic-pressure sensor. The first ECU receives the detection value of the hydraulic-pressure sensor through communication from the second ECU via the signal line to determine whether or not there is the abnormality in the hydraulic-pressure sensor in a second cycle that is shorter than the first cycle. When determining that the hydraulic-pressure sensor is abnormal, the first ECU controls driving of an electric actuator based on a braking command from an operation-amount detection sensor without using the detection value of the hydraulic-pressure sensor determined to be abnormal.