In-cylinder pressure based real-time combustion control for reduction of combustion dispersions in light-duty diesel engines

This paper proposes an in-cylinder pressure based real-time combustion control algorithm to reduce combustion dispersions from diesel engines. The proposed algorithm manipulates main injection quantity and timing as well as pilot injection quantity to control the Indicated Mean Effective Pressure (IMEP), crank angle location where 50% of Mass Fraction Burned (MFB50) and maximum value of Rate of Heat Release (ROHRmax). This control algorithm reduces the combustion dispersions by controlling the heat release curve for each operating condition. The proposed real-time combustion control structure mitigates combustion dispersions caused by operating condition changes, un-calibrated fuel injectors, and environmental condition variations, and it is validated with various experiments. In these experiments, various engine control variables were changed to validate the reduction in combustion dispersion when operating conditions change unintendedly. Changes in coolant temperature verified the compensation effect of the proposed algorithm under different external environments. It is validated with these experiments that there are 30% reduction in torque imbalances, a 10% emission dispersions reduction for NOx emissions, and a 65% reduction for PM emissions. (C) 2016 Elsevier Ltd. All rights reserved.