Internal Combustion Engine Fuel Injection Control for Mixed Fuel Stability
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Solution Overview
Problem
Dual-injection internal combustion engines face instability in fuel concentration due to changes in the mixing ratio of mixed fuels during refueling, leading to increased emissions and deteriorated drivability as the engine struggles to control fuel injection and ignition timing accurately when switching between pre- and post-refueling fuels.
Innovation Solution
A control device that dynamically adjusts the injection ratio between in-cylinder and port injection valves to ensure simultaneous fuel injection from both valves during changes in fuel mixing ratios, using a special mode that excludes 0:1 and 1:0 ratios to consume residual fuel and stabilize the fuel concentration, with threshold conditions for ending this mode based on integrated fuel amounts and air-fuel ratio sensor outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fuel injection amount is increased to compensate for lower heating value in high alcohol concentration fuel, then the drivability is improved, but emissions increase
Solution Approach 1:
The system dynamically adjusts the fuel injection amount parameter based on detected alcohol concentration changes. When refueling is detected and alcohol concentration changes, the control device modifies the injection amount to maintain optimal combustion, balancing drivability and emissions across varying fuel compositions.
Solution Approach 2:
The system uses feedback from alcohol concentration detection (via feedback correction amount of air-fuel ratio feedback control) to continuously adjust fuel injection amount. This closed-loop control ensures that injection amount is optimized for current fuel composition, preventing both excessive injection (increased emissions) and insufficient injection (deteriorated drivability).
2Object-generated harmful factors
If the ignition timing is retarded to increase exhaust gas temperature and reduce emissions, then emissions are reduced, but drivability deteriorates
Solution Approach 1:
The system dynamically adjusts the ignition timing parameter based on detected alcohol concentration. When refueling causes alcohol concentration changes, the control device modifies ignition timing to maintain optimal exhaust gas temperature and combustion efficiency, preventing both excessive emissions and drivability deterioration.
Solution Approach 2:
The system uses feedback from air-fuel ratio control and alcohol concentration detection to continuously optimize ignition timing. This ensures that ignition timing is adjusted according to actual fuel composition, maintaining the balance between emissions reduction and drivability across different alcohol concentrations.
3Adaptability or versatility
If the alcohol concentration of fuel is changed by refueling, then fuel flexibility is improved, but fuel concentration stability deteriorates during transition
Solution Approach 1:
The system performs preliminary detection of refueling events and proactively switches to a special control mode before the fuel transition is complete. By detecting refueling (through residual fuel amount sensor or other means) and anticipating alcohol concentration changes, the system prepares appropriate control strategies in advance, stabilizing fuel concentration management during the transition period.
Solution Approach 2:
The system dynamically switches between normal control mode and special control mode based on detected refueling events. During the transition period when fuel concentration is unstable, the special mode applies different control strategies (such as adjusted injection ratios between port and in-cylinder injection valves) to maintain stability, then returns to normal mode when transition is complete.
Data Source
AI summary
An object of this invention is, in an internal combustion engine having of in-cylinder direct injection and port injection, to enable the early elimination of a difference between fuel concentrations of fuel injected from different injection valves that can arise when a mixing ratio of different kinds of fuel contained in the fuel that is used changes significantly. To achieve this, the control device of this invention normally controls a fuel injection amount of each injection valve in accordance with the operating state of the internal combustion engine, while a change arose in the mixing ratio of different kinds of fuel contained in the fuel that is used or while there is a possibility for such a change, the control device controls a fuel injection amount of each injection valve so that fuel is temporarily injected from both the in-cylinder injection valve and the port injection valve.