A NUMERICAL STUDY ON A LIGHT-DUTY DIESEL ENGINE FUELED WITH BLENDS OF GASOLINE AND DIESEL

This study aims to numerically investigate the performance, combustion, and emission characteristics of a light-duty Diesel engine fueled with blends of gasoline and Diesel under various premixed combustion ratio (PCR). Simulations were performed using multidimensional computational fluid dynamics (CFD) software FIRE, which has physical submodels for multicomponent spray evaporation and multicomponent combustion implemented. The computational model was validated against the experimental results obtained using BG0 and BG20 fuel. Simulation results showed that at a low PCR condition, the difference between Diesel and gasoline in terms of ignitability and volatility properties gave insignificant influences to the performance, combustion, and emission characteristics of the engine. However, at high PCR condition, significant influences of the difference in ignitability and volatility properties between Diesel and gasoline on the performance, combustion, and emission characteristics were observed. As a result of increasing blended gasoline ratio, the longer ignition delay and the improved air-fuel mixing process led to the reduced soot emissions, and the CO emissions were also reduced due to the higher combustion temperature. The drawback of the combustion produced with higher blended gasoline ratio was that it led to a slight increase in NOx emissions. In addition, it can be considered that fueling with blends of gasoline and Diesel will inhibit the rapid combustion process in a certain extent, reduce the peak heat release rate, and depress the combustion noise compared to the conditions fueled with pure Diesel under high PCR.