Fuel control strategy for robust low-load gasoline low temperature combustion

To achieve robust low-load LTC (Low Temperature combustion), precise metering of fuel is required since the combustion is very sensitive to the variation of the injected fuel quantity, which could range from 1 to 3 mg per injection pulse. Open-loop calibration of individual injectors is simply not a practical option and therefore a fuel control strategy has been developed to ensure robust low-load LTC combustion and validated through experiments on a 2.2 L 4-cylinder LTC engine at two different coolant temperatures. The results show that the fuel control strategy significantly improves low-load LTC combustion stability by reducing cylinder-to-cylinder variation in delivered fuel masses due to different injector characteristics even when engine operating conditions are changed.