Pre-ignition Control via Enrichment Continuity
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Solution Overview
Problem
Existing engine control strategies for mitigating pre-ignition events are incomplete when a tip-out occurs during enrichment, leading to recurring pre-ignition issues at lower engine loads, which degrades engine performance and reduces engine life.
Innovation Solution
A method where the engine is enriched until a subsequent tip-out, and if the number of enrichment cycles between tip-in and tip-out is lower than a threshold, the enrichment is continued during subsequent tip-ins to complete the enrichment profile, even if no pre-ignition is detected, to maintain combustion chamber cooling and prevent thermal overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If enrichment is deactivated in response to a tip-out leading to incomplete pre-ignition mitigating enrichment, then engine response speed is improved, but pre-ignition events recur at lower engine loads degrading engine performance and life
Solution Approach 1:
The controller performs preliminary enrichment action by continuing enrichment cycles after a tip-out event even when no pre-ignition is currently detected. This preliminary action prevents future pre-ignition events by maintaining cooled combustion chambers, thereby resolving the contradiction between rapid response and preventing recurring pre-ignition that degrades engine life.
Solution Approach 2:
The enrichment action is made continuous by implementing a minimum number of enrichment cycles that must be completed regardless of tip-out events. This ensures the cooling effect is maintained continuously to prevent thermal overloading and recurring pre-ignition, while still allowing the system to respond quickly to driver demand.
2Object-affected harmful factors
If enrichment is applied to mitigate pre-ignition during tip-in events, then pre-ignition events are reduced, but engine performance degrades due to incomplete enrichment cycles when tip-out occurs
Solution Approach 1:
The system performs preliminary cooling through enrichment cycles before each tip-in event to prevent pre-ignition. By establishing this preliminary action, the engine maintains protected combustion chambers without requiring continuous enrichment, thus preventing pre-ignition while minimizing impact on engine performance and productivity.
Solution Approach 2:
The controller dynamically changes the enrichment parameter based on operating conditions, applying enrichment only when necessary (during tip-in events that may cause pre-ignition) and adjusting the minimum cycle count based on the specific operating context. This allows pre-ignition prevention while maintaining engine performance.
3Device complexity
If the enrichment strategy is abandoned after a tip-out event, then control system complexity is reduced, but thermal overloading occurs during subsequent tip-in events at lower loads
Solution Approach 1:
The controller implements a simplified preliminary action by automatically continuing a predetermined minimum number of enrichment cycles after a tip-out event. This simple rule prevents thermal overloading during subsequent tip-in events at lower loads without requiring complex real-time thermal management calculations, thus maintaining combustion chamber temperature control while avoiding excessive control system complexity.
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 approach effectively reduces pre-ignition events by ensuring complete enrichment cycles are completed, preemptively addressing incipient pre-ignition and reducing the likelihood of further events, thereby enhancing engine performance and extending engine life.
Implementation Method 1
By completing the enrichment over one or more subsequent tip-in events, including tip-in events at lower loads than those that typically trigger pre-ignition, sufficient combustion chamber cooling can be provided
Implementation Method 2
enrichment initiated responsive to pre-ignition induced during a tip-in may be completed and further pre-ignition may be mitigated
Data Source
AI summary
Methods and systems are provided for pre-ignition control. A pre-ignition mitigating enrichment is deactivated in response to a tip-out but reactivated in response to a subsequent tip-in. By preemptively enriching the engine, repeated pre-ignition due at subsequent tip-ins is reduced.