Filter Abnormality Detection via Exhaust Flow Rate Adjustment
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Solution Overview
Problem
The existing PM sensor systems in internal combustion engines face challenges in accurately detecting particulate matter (PM) due to variations in exhaust gas flow rates, leading to improper introduction of exhaust gas and subsequent degradation in detection accuracy, which complicates the determination of filter abnormality.
Innovation Solution
A filter abnormality determination system that adjusts the timing of abnormality determination based on the variation of exhaust gas flow rate, ensuring accurate PM detection by correlating the sensor output with the accumulated PM on the sensor element, and includes a determination timing unit to estimate and adjust the performing timing to avoid errors caused by flow rate disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the exhaust gas flow rate varies (e.g., when engine load increases), then the engine can operate under different load conditions, but the exhaust gas flow in the vicinity of the PM sensor is disturbed and the exhaust gas to be detected is not appropriately introduced into the body of the PM sensor, degrading detection accuracy
Solution Approach 1:
The control unit preliminarily determines a non-detection time period based on the detected variation of exhaust gas flow rate before the actual PM detection occurs. This advance preparation allows the system to anticipate and avoid performing detection during periods when exhaust gas flow disturbance is expected, thereby preventing inaccurate measurements while maintaining engine load adaptability.
2Reliability
If the PM sensor output is used to determine filter abnormality, then the filter status can be monitored, but when exhaust gas flow rate varies, the detection accuracy degrades leading to erroneous normality determinations
Solution Approach 1:
The control unit continuously monitors the exhaust gas flow rate and uses this feedback information to dynamically adjust the filter abnormality determination process. By detecting variations in exhaust gas flow rate and corresponding changes in PM sensor output, the system can identify when detection should be suspended due to flow disturbance, thereby maintaining reliability of filter status monitoring while adapting to varying engine conditions.
3Productivity
If abnormality determination is performed continuously, then real-time monitoring is maintained, but during exhaust gas flow variation periods, erroneous normality determinations are made
Solution Approach 1:
The control unit implements periodic monitoring of exhaust gas flow rate and uses this information to periodically suspend or resume filter abnormality determination. By alternating between active determination periods and suspension periods based on detected flow rate variations, the system maintains monitoring continuity through structured periodic action while preventing erroneous determinations during flow disturbance periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system enhances the accuracy of filter abnormality determination by ensuring proper PM accumulation on the sensor element, reducing erroneous normality determinations and improving detection reliability even under varying exhaust gas flow conditions.
Implementation Method 1
a PM sensor configured to introduce a part of exhaust gas flowing in the exhaust gas passage downstream of the filter into a sensor body and to correlate a sensor output with an amount of particulate matter accumulated on a sensor element in the sensor body
Data Source
AI summary
A filter abnormality determination system includes: a PM sensor configured to introduce a part of exhaust gas flowing in the exhaust gas passage on the downstream side of a filter into a sensor body and to correlate a sensor output with an amount of particulate matter accumulated on a sensor element in the sensor body; an abnormality determining unit configured to perform filter abnormality determination on the basis of the output of the PM sensor; a determination timing determining unit configured to determine a timing at which the abnormality determining unit performs the abnormality determination on the basis of an estimated amount of particulate matter accumulated on the sensor element; and a determination performing adjusting unit configured to adjust the performing timing determined by the determination timing determining unit depending on a variation of an exhaust gas flow rate per unit time in the exhaust gas passage in which the PM sensor is disposed.