Particulate Filter Failure Detection Using Outflow PM Monitoring
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Solution Overview
Problem
Detecting filter breakdown or failure immediately after regeneration is challenging due to low particulate matter deposition, making differential pressure-based methods ineffective, and requiring pressure sensors on both sides of the filter.
Innovation Solution
Monitoring the outflow particulate matter amount after regeneration and judging filter failure based on a predetermined reference amount and time, comparing outflow amounts at identical engine operation states to improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If differential pressure-based detection is used to detect filter failure, then detection capability is improved when PM deposition is sufficient, but detection becomes ineffective immediately after regeneration when PM deposition is extremely small
Solution Approach 1:
The patent changes the detection parameter from differential pressure to outflow PM amount. This parameter change enables effective detection immediately after regeneration because outflow PM amount remains detectable even when PM deposition is extremely small, whereas differential pressure becomes ineffective under the same conditions.
2Measurement precision
If pressure sensors are installed on both upstream and downstream sides of the filter to measure differential pressure, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the detection function from the differential pressure measurement system and relocates it to the outflow PM amount measurement system. This eliminates the need for two pressure sensors, reducing device complexity while maintaining detection functionality through the PM sensor already present in the exhaust gas passage.
3Reliability
If filter regeneration is performed to remove deposited PM, then filter performance is restored, but detection capability is temporarily lost due to insufficient PM for differential pressure measurement
Solution Approach 1:
The patent prepares the detection system by switching to outflow PM amount measurement before regeneration occurs. This preliminary action ensures that detection capability is already in place and can immediately function after regeneration when PM deposition is minimal, avoiding the detection gap that occurs with differential pressure-based methods.
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
Enables immediate and accurate detection of filter failures post-regeneration, enhancing the reliability of failure detection and reducing the need for multiple pressure sensors.
Implementation Method 1
a regeneration process executing section which executes a filter regeneration process for oxidizing and removing PM deposited in the particulate filter
Implementation Method 2
a particulate amount detection sensor that detects an amount of PM contained in an exhaust gas
Data Source
AI summary
An object of the present invention is to detect any breakdown or failure of a particulate filter more appropriately. A failure detecting apparatus for detecting failure of a particulate filter according to the present invention comprises an acquiring section which acquires an amount of PM contained in an exhaust gas allowed to outflow from the particulate filter; a regeneration process executing section which executes a filter regeneration process for oxidizing and removing PM deposited in the particulate filter; and a failure judging section which judges that the particulate filter is in the failure state if a decreased amount of the amount of PM contained in the exhaust gas acquired by the acquiring section, during a predetermined period of time as started from a point in time at which the execution of the filter regeneration process performed by the regeneration process executing section is completed, is not equal to or larger than a predetermined reference amount.