Internal Combustion Engine Misfire Detection and Ignition Timing Control
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Solution Overview
Problem
Conventional misfire determination apparatuses for internal combustion engines cannot identify the specific cylinder experiencing a misfire, leading to inadequate control over misfire suppression and combustion stability, which degrades exhaust gas characteristics and idle stability.
Innovation Solution
A control apparatus that includes a rotational speed parameter detection unit, single misfire detection unit, misfire counter, misfire determination unit, and ignition timing correction unit to accurately detect misfires in each cylinder and correct ignition timing to prevent misfires, thereby stabilizing combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comprehensive misfire determination is performed without cylinder identification, then misfire detection coverage is improved, but misfire localization capability deteriorates
Solution Approach 1:
The patent divides the engine's cylinders into individually monitorable units by associating misfire determination results with specific cylinder identifiers. The ECU processes rotational speed parameters separately for each cylinder and stores misfire determination results with cylinder identification information, enabling both comprehensive monitoring and precise localization of misfires.
2Productivity
If ignition timing is corrected without identifying the misfiring cylinder, then overall combustion control is improved, but targeted misfire suppression deteriorates
Solution Approach 1:
The patent applies local quality by correcting ignition timing specifically for the identified misfiring cylinder rather than uniformly adjusting all cylinders. The ECU determines which cylinder is misfiring based on rotational speed parameter analysis and applies ignition timing correction only to that specific cylinder, enabling targeted suppression while maintaining optimal combustion in other cylinders.
3Device complexity
If misfire determination is performed in comprehensive manner without cylinder identification, then system complexity is reduced, but combustion stability control deteriorates
Solution Approach 1:
The patent segments the misfire determination process into cylinder-specific analyses while using a unified ECU control system. The ECU calculates rotational speed parameters for each cylinder individually, associates results with cylinder identifiers, and maintains separate misfire determination results for each cylinder, achieving precise combustion stability control without requiring separate physical determination systems for each cylinder.
Data Source
AI summary
A control apparatus, for an internal combustion engine, detects a rotational speed parameter (time parameter) that represents a rotational speed of the internal combustion engine including a plurality of cylinders, detects a single misfire that is a misfire for every ignition for each of the plurality of cylinders, based on the rotational speed parameter that has been detected in each combustion stroke of the plurality of cylinders (steps 2 to 7 and 9), counts, as a misfire counter value, the number of times that the single misfire has been detected for each of the plurality of cylinders (steps 8 and 10), determines whether the misfire is occurring in the cylinder, based on the misfire counter value (steps 11 to 12), and corrects an ignition timing of the cylinder that has been determined that the misfire is occurring to an advance angle side (steps 25, 26, and 34).