Clutch Pedal Sensor Diagnostic False Failure Reduction
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Solution Overview
Problem
Existing clutch pedal position sensor diagnostic systems often register false failures when a vehicle is driven manually without the clutch pedal or when the engine is revved in neutral, leading to inaccurate diagnostics.
Innovation Solution
A diagnostic method that records maximum and minimum clutch pedal position sensor voltages only during a vehicle launch event, comparing the voltage difference to a threshold to determine if the sensor is functioning correctly, thereby preventing false failures by ensuring the clutch pedal is engaged during acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clutch pedal position sensor diagnostics are performed continuously using engine RPM to vehicle speed ratios, then diagnostic coverage is improved, but false failure registrations increase when vehicle is driven manually without clutch or engine is revved in neutral
Solution Approach 1:
The diagnostic system performs preliminary verification by checking multiple conditions (clutch pedal position, vehicle speed, gear state, accelerator pedal position) before initiating the diagnostic test. This preliminary action ensures that the diagnostic is only performed when the clutch pedal is actually engaged, preventing false failures while maintaining diagnostic accuracy.
Solution Approach 2:
The system changes the diagnostic parameters from continuous monitoring to event-based monitoring. Instead of continuously checking RPM to speed ratios, the system monitors for specific launch events where multiple parameters (clutch position, vehicle speed, gear state) are simultaneously satisfied, thereby improving measurement precision by eliminating false positives.
2Difficulty of detecting and measuring
If clutch diagnostic systems monitor engine RPM to vehicle speed ratios, then diagnostic capability is improved, but false failures occur during manual driving without clutch engagement
Solution Approach 1:
The system introduces an intermediary verification step by using the clutch pedal position sensor as a mediator. Before performing the diagnostic based on RPM to speed ratios, the system first verifies that the clutch pedal position sensor indicates the pedal is engaged. This intermediary check ensures that the diagnostic is only performed when clutch engagement is actually occurring, eliminating false failures during manual driving without clutch.
3Productivity
If clutch pedal position sensor diagnostics are performed during all vehicle operations, then comprehensive monitoring is achieved, but false failures are registered during engine revving in neutral
Solution Approach 1:
The diagnostic system dynamically adjusts its operation based on real-time vehicle conditions. Instead of performing diagnostics during all vehicle operations, the system dynamically enables or disables the diagnostic based on whether a launch event is detected. This dynamic approach maintains comprehensive monitoring coverage while preventing false failures during engine revving in neutral by only activating diagnostics when appropriate conditions are met.
Data Source
AI summary
A system and method of diagnosing a clutch pedal position sensor of a vehicle includes determining if a speed of the vehicle speed is less than a first predetermined speed, recording a maximum clutch pedal voltage, determining if a vehicle launch event is in progress, recording a minimum clutch pedal voltage, determining a voltage difference between the maximum clutch pedal voltage and the minimum clutch pedal voltage, and declaring a clutch pedal position sensor fault based on a comparison between the voltage difference and a threshold voltage.