Vehicle Temperature Sensor Diagnosis Using Cooling Rate Comparison
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Solution Overview
Problem
Existing sensor diagnostic methods for temperature sensors in vehicles require a long soak time to determine sensor abnormalities, making it difficult to early detect such issues.
Innovation Solution
A sensor diagnostic device using a control system with a processor and memory to calculate temperature differences and decrease speeds between two temperature sensors, allowing for early detection of abnormalities without waiting for the soak time by comparing the absolute values of these differences against predefined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long soak time is used to determine sensor abnormalities, then the reliability of temperature sensor operation is improved, but the time required for diagnosis increases
Solution Approach 1:
The system performs preliminary calculations of decrease speeds during the soak period, and uses these pre-calculated values to enable early determination of sensor abnormalities before the full soak time elapses. This allows the diagnosis to start earlier while maintaining reliability.
Solution Approach 2:
The system continuously monitors temperature differences and decrease speeds, providing feedback that enables dynamic determination of sensor status. By comparing real-time decrease speed differences against thresholds, the system can reliably detect abnormalities without waiting for the complete soak period.
2Productivity
If early detection of sensor abnormalities is implemented, then the productivity of vehicle control systems is improved, but the measurement precision of temperature differences may be compromised
Solution Approach 1:
The system changes the parameter used for diagnosis from absolute temperature difference to decrease speed difference. This allows early detection by monitoring the rate of temperature change, which can be reliably measured even when absolute temperature differences are still developing, thus maintaining precision while enabling earlier detection.
3Device complexity
If the diagnosis is performed based on temperature difference alone, then the device complexity is reduced, but the reliability of abnormality detection decreases
Solution Approach 1:
The system pre-calculates and stores decrease speed values during the soak period, making these preliminary calculations available for immediate comparison. This maintains a relatively simple device structure while improving reliability by having pre-processed data ready for early abnormality detection.
Data Source
AI summary
A sensor diagnostic device for use in a vehicle including a first temperature sensor and a second temperature sensor includes a control system. The control system includes a processor and a memory communicably coupled to each other. The control system determines a sensor abnormality based on a detected temperature difference between a first detected temperature detected by the first temperature sensor and a second detected temperature detected by the second temperature sensor. After the vehicle is stopped, the control system calculates a decrease speed of the first detected temperature based on the first detected temperature, and calculate a decrease speed of the second detected temperature based on the second detected temperature, and if an absolute value of a decrease speed difference between the first and second detected temperatures is smaller than a threshold, determines whether the sensor abnormality has occurred, based on the detected temperature difference.