Misfire Detection Using Dual-Angle Rotation Fluctuation
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Solution Overview
Problem
Existing misfire detection devices for internal combustion engines face challenges in accurately determining misfires, especially when the deactivating process is executed, due to tolerance errors in crankshaft rotation fluctuation measurements, leading to erroneous determinations.
Innovation Solution
The proposed misfire detection device calculates two rotation fluctuation amounts using different specific angles and determines misfires based on their relative magnitudes or absolute values, employing a second determining process that uses a larger angle to minimize tolerance influence, especially during the deactivating process, thereby enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rotation fluctuation amount is used for misfire detection, then the detection process is simple, but tolerance errors in crankshaft rotation measurements lead to erroneous misfire determinations
Solution Approach 1:
The patent divides the rotation fluctuation measurement into multiple segments by calculating rotation fluctuation amounts at different specific angles (first specific angle and second specific angle). This segmentation allows the system to compare multiple measurement points, thereby reducing the impact of tolerance errors in any single measurement while maintaining a manageable detection process.
2Productivity
If the deactivating process is executed to regenerate the aftertreatment device, then the aftertreatment device can be regenerated, but the misfire detection becomes inaccurate due to tolerance errors in rotation fluctuation measurements
Solution Approach 1:
The patent performs preliminary comparison of rotation fluctuation amounts calculated at different specific angles before making a misfire determination. By预先 comparing the first rotation fluctuation amount (at first specific angle) with the second rotation fluctuation amount (at second specific angle), the system can identify and compensate for tolerance errors that occur during the deactivating process, ensuring accurate misfire detection even when regeneration is occurring.
3Measurement precision
If a larger angle interval is used for rotation fluctuation measurement, then tolerance influence is reduced, but the measurement interval increases
Solution Approach 1:
The patent addresses the angular interval issue by introducing a temporal dimension to the measurement. Instead of using a single large angular interval, the system calculates rotation fluctuation amounts at multiple smaller angular intervals (first specific angle and second specific angle) and compares them over time. This allows the system to reduce tolerance influence through multiple measurements while keeping each individual measurement interval manageable.
Data Source
AI summary
A misfire detection device and method for an internal combustion engine are provided. A deactivating process deactivates combustion control for air-fuel mixture in a deactivated cylinder. An instantaneous speed variable indicates a speed in a case where a crankshaft rotates by a specific angle. The specific angle of the first instantaneous speed variable is a first angle. The specific angle of the second instantaneous speed variable is a second angle greater than the first angle. A second determining process determines whether a misfire has occurred from a magnitude of a rotation fluctuation amount of a subject of determination, instead of a relative magnitude of the rotation fluctuation amount of the subject of the determination relative to a reference rotation fluctuation amount, when the reference rotation fluctuation amount is a rotation fluctuation amount of the deactivated cylinder during the execution of the deactivating process.