Filter Malfunction Detection Using Sensor Offset Correction
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Solution Overview
Problem
Existing filter malfunction determination apparatuses in engines can erroneously detect malfunctions due to particulate matter adhering to the exhaust pipe or filter device, leading to inefficient malfunction determination and potential false positives.
Innovation Solution
A filter malfunction determination apparatus that includes a malfunction determiner, a rapid increase determiner, a calculator, and an offset corrector to assess parameter values from a PM sensor, calculating correction values based on changes in particulate matter adhesion to accurately distinguish between actual malfunctions and erroneous readings caused by bulk particulate matter adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional filter malfunction determination apparatus uses a PM sensor to detect particulate matter accumulation, then malfunction detection capability is provided, but erroneous determination occurs when bulk particulate matter is deposited between the opposite electrodes
Solution Approach 1:
The system performs preliminary detection of rapid output increases in the PM sensor signal. When a rapid increase is detected, the system calculates the change amount and applies offset correction before the erroneous malfunction determination can occur. This preliminary action prevents the false positive that would result from bulk particulate matter deposition.
Solution Approach 2:
The system continuously monitors the PM sensor output and uses feedback control to detect rapid changes. When a rapid increase is detected, the system calculates the change amount, determines it is caused by bulk particulate matter, and applies offset correction to the malfunction determination threshold or parameter value. This feedback mechanism dynamically adjusts the determination criteria to maintain accuracy.
2Reliability
If heater regeneration is performed to eliminate bulk particulate matter from the PM sensor, then erroneous determination is prevented, but execution efficiency of malfunction determination significantly decreases
Solution Approach 1:
Instead of performing full heater regeneration every time bulk particulate matter is detected, the system applies only the necessary offset correction to the parameter value or malfunction determination threshold. This partial action (offset correction) is sufficient to prevent erroneous determination without the time-consuming heater regeneration process, thereby maintaining high execution efficiency.
Solution Approach 2:
The system changes the parameter value or malfunction determination threshold by applying an offset correction calculated from the rapid increase amount. This parameter change approach allows the system to adapt to bulk particulate matter deposition without physical cleaning, maintaining both accuracy and efficiency.
3Measurement precision
If the malfunction determination threshold is set to detect all particulate matter accumulation, then sensitivity is improved, but false positives increase due to bulk particulate matter deposition
Solution Approach 1:
The system dynamically adjusts the malfunction determination threshold or parameter value based on detected rapid increases. When bulk particulate matter is detected through rapid increase analysis, the system applies offset correction to raise the effective threshold, preventing false positives while maintaining high sensitivity for actual malfunction conditions.
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 solution reduces erroneous malfunction detections, enhances the efficiency of filter malfunction determination by correcting parameter values and thresholds, ensuring accurate assessment of filter device performance.
Implementation Method 1
The filter malfunction determination apparatus uses a reduction in the resistance across the opposite electrodes due to the amount of deposited particulate matter between the opposite electrodes
Implementation Method 2
a heater mounted to the PM sensor heats the PM sensor
Data Source
AI summary
A filter malfunction determination apparatus includes a calculator that calculates, upon determination that a rapid output increase has occurred, an amount of change of a parameter value output from a sensor before and after the rapid output increase. The calculator calculates, based on the calculated amount of change, a correction value for correcting at least one of the parameter value output from the sensor and a malfunction determination threshold. The filter malfunction determination apparatus includes an offset corrector configured to perform, based on the correction value, offset correction of at least one of the parameter value output from the sensor and the malfunction determination threshold after determination that the rapid output increase has occurred.