Spark Ignition Engine Cylinder Stability Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ignition control systems for spark ignition engines fail to account for variations in Exhaust Gas Recirculation (EGR) amounts among cylinders, leading to degraded combustion performance and stability, and are unable to specifically identify cylinders causing these variations to effectively mitigate the issue.
Innovation Solution
The system detects cylinders with excessive EGR amounts using air-fuel ratio sensors and adjusts ignition timing or energy to maintain stability, by advancing the ignition timing or increasing ignition energy for cylinders with rich air-fuel ratios and lagging or increasing fuel injection for others, thereby correcting the combustion stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If EGR means is used to recirculate exhaust to combustion chamber, then combustion efficiency is improved, but combustion stability is degraded due to variation in EGR amount among cylinders
Solution Approach 1:
The control device applies different ignition timing corrections to different cylinders based on their individual air-fuel ratios. The ignition timing of the rich cylinder (excessive EGR) is advanced, while other cylinders maintain standard timing, creating localized quality differences to compensate for EGR distribution variations and restore combustion stability.
Solution Approach 2:
The system changes the ignition timing parameter dynamically based on detected air-fuel ratio variations. When a cylinder is detected to have excessive EGR (rich air-fuel ratio), its ignition timing is advanced by a predetermined angle, while other cylinders maintain standard timing, thereby adjusting the combustion parameters to compensate for EGR-induced instability.
2Device complexity
If uniform ignition timing is applied to all cylinders, then control simplicity is maintained, but combustion stability is degraded when EGR amount varies among cylinders
Solution Approach 1:
Instead of uniform ignition timing across all cylinders, the system implements localized quality control by detecting which specific cylinder has excessive EGR and applying ignition timing correction only to that cylinder. This maintains simplicity in the overall control logic while achieving stability through targeted local adjustments.
Solution Approach 2:
The control device uses the air-fuel ratio detection system to automatically identify cylinders with excessive EGR and self-corrects by adjusting ignition timing for those specific cylinders. The system serves itself by using its own detection capabilities to trigger appropriate control actions without external intervention.
3Stability of the object's composition
If air-fuel ratio detection is implemented for each cylinder, then combustion stability can be maintained, but device complexity increases
Solution Approach 1:
The air-fuel ratio sensor in the exhaust manifold serves as an intermediary device that indirectly detects the air-fuel ratio of each cylinder by analyzing the periodic variations in exhaust gas composition. This mediator approach allows individual cylinder detection without requiring direct sensors in each cylinder, thereby maintaining combustion stability while limiting the increase in device complexity.
Solution Approach 2:
The system creates a temporal copy of the air-fuel ratio information for each cylinder through periodic sampling of the exhaust gas composition. By analyzing the periodic variations in the exhaust manifold, the system reconstructs individual cylinder air-fuel ratio data without requiring physical duplication of sensors in each cylinder, thus achieving individual cylinder monitoring with limited additional complexity.
Data Source
AI summary
The present invention suppresses the worsening of stability due to a variation in EGR amounts between cylinders in a spark ignition engine. An engine control device for controlling a spark ignition engine equipped with an EGR means for recirculating exhaust gas in a combustion chamber and an air-fuel-ratio detection means for detecting the air-fuel ratio in each cylinder, the engine control device being characterized by being equipped with a means for changing the parameters for ignition control of a rich cylinder, when the air-fuel ratio of cylinders varies and there are richer cylinders and leaner cylinders relative to a prescribed air-fuel ratio during the execution of exhaust gas recirculation by the EGR means.