Humidity Sensor Self-Diagnosis via Gas Flow Comparison
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Solution Overview
Problem
Existing humidity sensor diagnostics in engine systems rely on multiple sensors for accurate degradation assessment, which is not always feasible, and the accuracy of one sensor depends on the proper functioning of others, leading to potential inaccuracies in determining sensor degradation.
Innovation Solution
A method that adjusts engine operating parameters based on humidity measurements from a single humidity sensor and indicates degradation by comparing its output with a second gas flow of known or different humidity, allowing for degradation detection even without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple humidity sensors are used for degradation assessment, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The humidity sensor performs self-diagnosis by comparing its own measurements taken under different operating conditions (different gas flows with different humidities). The sensor uses its own output signals to detect degradation, eliminating the need for additional reference sensors. This self-service approach resolves the contradiction by maintaining measurement precision through internal comparison while avoiding the device complexity of multiple sensors.
2Reliability
If multiple humidity sensors are used for degradation assessment, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The single humidity sensor performs multiple functions: it measures humidity for engine control and simultaneously performs self-diagnosis for degradation detection. By making the sensor multi-functional, the system achieves reliable degradation detection without requiring additional sensors, thereby improving ease of manufacture while maintaining reliability.
3Measurement precision
If the accuracy of one sensor depends on other sensors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The humidity sensor determines its own accuracy by comparing measurements under different operating conditions rather than relying on other sensors. This self-validation approach eliminates sensor interdependence while maintaining measurement precision, resolving the contradiction between accuracy and device complexity.
Data Source
AI summary
Embodiments for diagnosing a humidity sensor are provided. One example method comprises adjusting an engine operating parameter based on humidity of a first gas flow measured by a humidity sensor, and indicating degradation of the humidity sensor if a humidity of a second gas flow measured by the humidity sensor is different than an expected humidity. In this way, degradation of the humidity sensor may be indicated if the humidity of the second gas flow measured by the humidity sensor is different than expected.