Wheel Speed Sensor Rationalization Using Longitudinal Acceleration
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Solution Overview
Problem
Existing vehicle wheel speed sensors often fail to provide a non-zero output, leading to inaccurate vehicle speed and acceleration measurements, which existing verification methods struggle to detect without falsely indicating functional sensors as malfunctioning.
Innovation Solution
A method utilizing a longitudinal accelerometer to verify the operational status of wheel speed sensors by checking for non-zero output during acceleration events, setting thresholds to distinguish valid signals from noise, and incrementing error counters for consistent failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel speed sensor output is continuously monitored to detect sensor failures, then sensor reliability is improved, but false diagnostics occur due to noise and low-level interference
Solution Approach 1:
The patent changes the parameter being monitored from continuous wheel speed sensor output to wheel acceleration (derivative of wheel speed). This parameter transformation allows the system to detect sensor failures by comparing expected acceleration during braking events with actual sensor readings, thereby improving reliability while avoiding false diagnostics caused by noise in continuous speed monitoring.
Solution Approach 2:
The patent introduces an intermediary calculation step by computing wheel acceleration from wheel speed data and using this derived parameter as the basis for failure detection. This intermediary approach filters out low-level interference and noise present in raw wheel speed signals, enabling more accurate failure detection without false positives.
2Measurement precision
If acceleration thresholds are set to distinguish valid signals from noise, then false diagnostics are reduced, but detection sensitivity may decrease
Solution Approach 1:
The patent performs preliminary action by calculating wheel acceleration from wheel speed data before conducting failure detection. This pre-processing step transforms the raw sensor data into a form where failure patterns are more distinct and easier to detect with thresholds, thereby maintaining high detection sensitivity while reducing false diagnostics.
Solution Approach 2:
The patent applies dynamic thresholds for wheel acceleration that adapt based on vehicle operating conditions. Rather than using fixed thresholds, the system adjusts acceleration thresholds according to the magnitude of wheel acceleration and braking events, maintaining high detection sensitivity across varying operating conditions while still effectively distinguishing valid signals from noise.
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
Effectively identifies common wheel speed sensor failures by ensuring non-zero output during acceleration, reducing false diagnostics and enhancing sensor reliability in vehicle systems.
Implementation Method 1
A longitudinal accelerometer is utilized to verify the operational status of wheel speed sensors
Implementation Method 2
a wheel speed sensor to sense a wheel speed and to provide an output signal indicative of the magnitude of wheel speed
Data Source
AI summary
A method of rationalizing operation of a vehicle wheel speed sensor is provided. The method includes the steps of receiving an output signal from a longitudinal accelerometer, receiving an output signal from a wheel speed sensor, determining whether an acceleration event exists based on the output signal from the longitudinal accelerometer, evaluating the wheel speed sensor output signal during the acceleration event, and determining whether the wheel speed sensor signal exceeds a set threshold value during the acceleration event.