Misfire Detection Device for Internal Combustion Engine Regeneration
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Solution Overview
Problem
The accuracy of misfire detection in internal combustion engines is compromised when regeneration processes overlap with torque fluctuations, leading to decreased determination accuracy of returning to a normal state due to periodic torque miss and rotational fluctuations.
Innovation Solution
A misfire detection device that temporarily determines misfire occurrence based on crankshaft rotational fluctuations, regularly confirms misfires based on predetermined proportions, and determines engine normalcy without incorporating temporary determination results during regeneration processes, using designation variables to store and apply determination results for accurate state assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regeneration process is performed by stopping combustion control in some cylinders, then exhaust gas regeneration is achieved, but misfire detection accuracy deteriorates due to overlapping torque fluctuations
Solution Approach 1:
The patent segments the determination period into multiple sub-periods based on the regeneration process state. The control device identifies whether the engine is in a regeneration process and divides the monitoring period accordingly, allowing separate evaluation of misfire likelihood in regeneration periods versus non-regeneration periods. This segmentation enables accurate misfire detection by preventing false positives during planned torque fluctuations from regeneration.
2Speed
If temporary determination of misfire is performed continuously, then misfire detection responsiveness is improved, but false determination increases during regeneration process
Solution Approach 1:
The patent implements dynamic adjustment of the determination logic based on the regeneration process state. The control device continuously monitors regeneration status and dynamically modifies how temporary determination results are evaluated - during regeneration, the system recognizes expected torque fluctuations and adjusts the threshold or weighting for misfire determination. This dynamic adaptation maintains high responsiveness while preventing false determinations during planned operational changes.
3Use of energy by moving object
If combustion control is stopped in some cylinders for regeneration, then fuel economy is improved, but rotational fluctuation magnitude decreases making misfire harder to detect
Solution Approach 1:
The patent introduces the regeneration process state as an intermediary variable that mediates between the combustion control stopping and misfire detection. By monitoring this intermediary state, the control device can distinguish between rotational fluctuations caused by intentional combustion control changes versus those caused by actual misfires. This intermediary information allows the system to maintain fuel-efficient regeneration operations while preserving accurate misfire detection capability through contextual interpretation of rotational data.
Data Source
AI summary
A CPU stops combustion control of Cylinder #1 in order to perform a regeneration process of a GPF and performs a regeneration process of causing an air-fuel ratio of an air-fuel mixture in Cylinders #2 to #4 to be richer. When it is determined that a misfire has occurred because a misfire rate when the regeneration process is not being performed is equal to or greater than a predetermined value, the CPU determines that an internal combustion engine has returned to a normal state based on the premise that the misfire rate when the regeneration process is not being performed decreases.