Dual Throttle Position Sensor Diagnostic System for Engine Stalling Prevention
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Solution Overview
Problem
Engine control systems with multiple throttle position sensors often experience out of correlation (OOC) and out of range (OOR) errors, leading to engine stalling and incorrect fault diagnostics due to differences between sensor readings, which conventional systems struggle to accurately detect and manage.
Innovation Solution
A diagnostic system that includes an OOC detection module, an OOR detection module, and counters to differentiate and manage OOC and OOR errors, allowing the control module to adjust throttle positions and disable airflow diagnostics to prevent false error detection and engine stalling, enabling the engine to operate in a 'limp home' mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the higher of the two TPS sensors is selected during OOC error, then the system can continue operating, but the engine may stall due to incorrect throttle positioning
Solution Approach 1:
The patent segments the error detection into two distinct parts: OOC (out of correlation) detection between the two TPS sensors, and OOR (out of range) detection for each individual sensor. This segmentation allows the system to identify whether the issue is a discrepancy between sensors or an actual sensor failure, preventing incorrect throttle positioning and engine stalling by applying appropriate handling for each error type
Solution Approach 2:
The patent introduces counter mechanisms as intermediaries that track the frequency and duration of OOC and OOR conditions. These counters act as mediators between the raw sensor signals and the control decisions, allowing the system to distinguish between transient noise and genuine faults, thereby preventing premature engine shutdown or stalling
2Reliability
If the system uses multiple TPS sensors for redundancy, then fault detection capability is improved, but complexity of error differentiation and management increases
Solution Approach 1:
The patent divides the diagnostic logic into separate modules: one for detecting OOC errors (comparing the two TPS readings) and another for detecting OOR errors (checking each TPS against its valid range). This segmentation simplifies the overall complexity by handling each error type independently with dedicated logic, rather than attempting to manage all possibilities in a single complex algorithm
Solution Approach 2:
The patent performs preliminary classification of sensor errors by first checking for OOC conditions and then for OOR conditions. This preliminary action establishes a clear decision hierarchy that simplifies subsequent control actions, preventing the need for complex real-time analysis of multiple simultaneous error conditions
3Measurement precision
If OOR count threshold is set lower than OOC count threshold, then OOR errors are detected earlier, but false error detection may increase
Solution Approach 1:
The patent applies different threshold criteria locally to different error types: a lower threshold for OOR errors (which represent actual sensor failures) and a higher threshold for OOC errors (which represent sensor discrepancies). This local differentiation of detection sensitivity allows early detection of genuine sensor failures while maintaining higher confidence requirements for correlation errors, reducing false positives
Data Source
AI summary
A system includes an out of correlation (OOC) detection module that detects an OOC error between a first throttle position sensor (TPS) and a second TPS. An out of range (OOR) detection module that detects first and second OOR errors for the first and second TPS, respectively. An OOC counter sets an OOC error when an OOC count is greater than or equal to a first OOC value. An OOR counter sets first and second OOR errors when first and second OOR counts, respectively, are greater than or equal to a second OOR value that is less than the first OOC value. A control module increments the counters when the respective errors occur and sets at least one of the first and second OOR counts equal to the OOC count when at least one of the first and second OOR errors occur after the OOC error.