Engine Control Device Retards Ignition Timing After Refueling
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Solution Overview
Problem
Internal combustion engines using blended fuels of gasoline and alcohol face knocking issues after refueling without a sensor to detect the alcohol mixing ratio, as existing control systems rely on such sensors for optimal ignition timing and air-fuel ratio adjustments.
Innovation Solution
A control device for internal combustion engines that includes refueling detection, mixing ratio estimation based on engine operation, and ignition timing adjustment to a retarded setting until the estimation is complete, allowing for stable operation without a sensor to detect the alcohol mixing ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor that detects the mixing ratio of alcohol is provided, then the ignition timing and air-fuel ratio can be controlled based on the detection value, but the device complexity increases
Solution Approach 1:
The system uses the engine's own operational parameters (intake air amount, fuel injection amount, engine speed) to estimate the alcohol mixing ratio, eliminating the need for external sensors. The control unit performs self-diagnosis by comparing expected versus actual engine behavior to infer fuel composition.
Solution Approach 2:
The patent replaces the physical alcohol mixing ratio sensor with a computational estimation system that uses mathematical models and operational data processing. The control unit calculates the mixing ratio based on measured engine parameters rather than direct physical detection.
2Reliability
If the ignition timing is rapidly changed in response to a change in alcohol mixing ratio, then knocking can be prevented, but the control stability deteriorates during the transition period
Solution Approach 1:
The system detects refueling events in advance and proactively switches to a safe ignition timing strategy (most retarded value) before the alcohol mixing ratio estimation is complete. This preliminary action prevents knocking that would occur during the transition period while the system adapts to new fuel conditions.
Solution Approach 2:
The ignition timing control dynamically adjusts based on the estimation completion status. During the transition period after refueling, the system uses the most retarded ignition timing, and once estimation is complete, it transitions to optimal ignition timing based on the estimated mixing ratio, creating a smooth adaptive control strategy.
3Reliability
If the most retarded ignition timing is used until sensor output is corrected after refueling, then knocking can be inhibited, but the productivity decreases due to suboptimal combustion
Solution Approach 1:
The system quickly estimates the alcohol mixing ratio using engine operational data, enabling a rapid transition from conservative ignition timing to optimized ignition timing. This self-service estimation approach minimizes the duration of suboptimal combustion by independently determining fuel composition without waiting for sensor correction.
Solution Approach 2:
The system rushes through the transition period by using refueling detection and operational parameter analysis to quickly establish the new alcohol mixing ratio. This allows the system to skip the prolonged period of using most retarded ignition timing, thereby minimizing productivity loss while still preventing knocking.
Data Source
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AI summary
A control device for an internal combustion engine includes refueling detection means (S105) for detecting refueling, mixing ratio estimating means (S112) for estimating a mixing ratio of alcohol contained in fuel, estimation completion determining means (S113) for determining whether estimation is completed by the mixing ratio estimating means (S112), and ignition control means (S107) for igniting an igniter at an ignition timing that is retarded from an optimum ignition timing based on an actual mixing ratio, during a predetermined period until the estimation completion determining means (S113) determines that the estimation is completed after detection of refueling.