Phi-T map analysis on RCCI engine fueled by methanol and biodiesel

Abstract

In this work, a 3-dimensional numerical platform coupled with skeletal chemical reaction mechanism is employed to investigate the impact of various operating conditions on the performance and emissions of a RCCI engine fueled with biodiesel and methanol. Especially, a φ-T map was employed to investigate the methanol percentage on the performance of the engine. The results indicated that the groups of cells distributed at high ER (above 2.0) decrease as methanol percentage increases. When the engine is operating at full load conditions, compared to pure biodiesel, the IMEP of the RCCI engine with 60% methanol increases by 10.2%, soot emissions significantly drops by 75%, but the NOx emissions increases by 12.3%. This is because the increase of methanol percentage creates a better mixing between the fuel and air and resulting in a faster and more homogeneous combustion process. However, when the engine is operating at 10% load conditions, with the increase of methanol percentage, the combustion will be deteriorated. For extreme case, when methanol percentage increases to 80%, misfire takes place in the engine due to its significant higher latent heat and specific heat of the methanol.