NOx Sensor Failure Prediction via Start-up Noise Analysis
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Solution Overview
Problem
Existing NOx sensor diagnostics fail to provide early warnings of impending failure, leading to inconvenient and unexpected breakdowns, as they only detect severe noise levels after a total breakdown has occurred.
Innovation Solution
A method that estimates the noise level of NOx sensor output signals during start-up and operating intervals, predicting failure by comparing noise levels with predefined thresholds, allowing for timely replacement and informing drivers of impending issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise level detection is performed continuously, then detection precision is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic noise level detection during specific start-up time intervals (e.g., 5-30 seconds after sensor start) rather than continuous monitoring. This periodic approach during critical periods achieves reliable failure prediction while significantly reducing energy consumption compared to continuous monitoring.
2Reliability
If noise level threshold is set low, then reliability is improved, but false alarms increase
Solution Approach 1:
The patent applies different noise level thresholds for different time intervals within the start-up period. Lower thresholds are applied during early start-up phases when higher noise is normal, while stricter thresholds are applied later when the sensor should be stabilizing. This localized quality approach improves reliability without generating excessive false alarms.
Solution Approach 2:
The patent uses dynamic threshold adjustment based on the sensor's start-up phase and operating conditions. The threshold is not fixed but adapts to the expected noise characteristics at different moments during start-up, allowing reliable detection while accommodating normal variations and preventing false alarms.
3Measurement precision
If monitoring time interval is extended, then detection precision is improved, but loss of time increases
Solution Approach 1:
The patent performs noise level monitoring during the start-up phase (first 30-60 seconds) to predict upcoming failures before they occur during normal operation. This preliminary detection during a naturally occurring interval provides early warning with sufficient lead time for maintenance planning, achieving both precision and timely notification.
Data Source
AI summary
The present disclosure relates to predicting and detecting an upcoming failure of a NOx sensor. In particular, the disclosure relates to a method for predicting an upcoming failure of a NOx sensor. The disclosure also relates to corresponding control arrangement and computer program, and to a vehicle comprising the control arrangement. The disclosure proposes a method for predicting an upcoming failure of a NOx sensor arranged. The method comprises estimating a noise level of an output signal of the NOx sensor. The estimation is performed after at least one sensor start and during at least one start-up time interval when an output signal level of the NOx sensor is settling towards a valid value. The method further comprises predicting an upcoming failure of the NOx sensor based on the estimated noise level exceeding a certain noise level during the at least one start-up time interval.