Engine Misfire Detection via Unburned Fuel Concentration
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Solution Overview
Problem
Existing misfire detection systems in engines often stop the engine unnecessarily, even when there is no risk of unburned fuel combustion in the exhaust gas duct, leading to operational problems and potential power outages.
Innovation Solution
A misfire detection device and method that includes a misfire detection part, an effective misfire determination part, and an engine stop processing control part. The effective misfire determination part assesses the risk of unburned fuel combustion in the exhaust gas duct based on an unburned parameter, and the engine stop processing control part only stops the engine when an effective misfire is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If misfire detection control is applied to stop the engine when misfire occurs, then safety is ensured by preventing unburned fuel combustion in exhaust gas duct, but operational continuity deteriorates due to unnecessary engine stoppages during transient states
Solution Approach 1:
The invention changes the parameter used for misfire evaluation from a simple binary detection to a quantitative assessment based on unburned fuel concentration in the exhaust gas. By measuring the actual concentration of unburned fuel and comparing it against threshold values, the system adapts its response based on the severity of the misfire condition, allowing it to distinguish between hazardous and non-hazardous situations.
Solution Approach 2:
The invention introduces an intermediary assessment layer between misfire detection and engine stoppage. The unburned fuel concentration measurement acts as an intermediary parameter that mediates between the detection of misfire and the decision to stop the engine, providing a nuanced evaluation that prevents unnecessary stoppages while ensuring safety when truly needed.
2Object-affected harmful factors
If engine stop processing is performed for all misfire cases, then harmful effects are eliminated by preventing potential combustion, but loss of time occurs due to unnecessary stoppages during transient load changes
Solution Approach 1:
The invention changes the parameter for determining engine stoppage from a binary misfire flag to a continuous measurement of unburned fuel concentration. This allows the system to evaluate the actual hazard level and make informed decisions about whether engine stoppage is necessary, thereby reducing unnecessary time loss while maintaining safety.
Solution Approach 2:
The invention applies partial action by selectively stopping the engine only when the unburned fuel concentration exceeds hazardous thresholds, rather than stopping for all misfire conditions. This partial application of the stoppage action eliminates the excessive time loss associated with stopping during non-hazardous transient states while still providing full protection when needed.
3Measurement precision
If misfire detection sensitivity is increased to detect all potential misfires, then measurement precision improves, but false detection increases during transient states with reduced fuel supply
Solution Approach 1:
The invention introduces unburned fuel concentration measurement as an intermediary verification step between misfire detection and false positive elimination. This intermediary measurement provides objective evidence to distinguish between actual hazardous misfires and transient conditions that mimic misfire symptoms, thereby eliminating false detections while maintaining high detection sensitivity.
Solution Approach 2:
The system uses feedback from unburned fuel concentration measurements to validate misfire detections. When a misfire is detected, the system checks the unburned fuel concentration to confirm whether the detection represents a true hazard or a false positive due to transient conditions, creating a feedback loop that improves detection accuracy.
Data Source
AI summary
A misfire detection device for an engine, includes: a misfire detection part for detecting a misfire state in at least one cylinder of the engine; an effective misfire determination part for determining, on the basis of an unburned parameter that is an indicator of an unburned fuel concentration in an exhaust gas duct, a risk of unburned fuel in the exhaust gas duct burning, when the misfire detection part detects the misfire state; and an engine stop processing control part for performing stop processing of the engine on the basis of a determination result in the effective misfire determination part.