EFFECT OF FUEL INJECTION PRESSURE ON COMBUSTION CHARACTERISTICS OF GASOLINE-BIODIESEL MIXTURES IN A RAPID COMPRESSION AND EXPANSION MACHINE

Abstract

In this research, experimental investigations were conducted to determine the characteristic of two Gasoline-Biodiesel mixtures (G90B10 and G80B20) on rapid compression and expansion machine (RCEM) that have similar characteristics with Compression Ignition (CI) engines. Different fuel injection pressures between 800-1400 bar were applied. The result shows that G90B10 has higher fuel injection rates than G80B20 at fuel injection pressure from 800-1400 bar. The G80B20 has a shorter ignition delay than the G90B10 at the same fuel injection pressure between 800-1400 bar. G90B10 has a lower burn or combustion duration than G80B20 due to a higher calorific value of the former. The fuel blend G90B10 displays its best enhancement of brake thermal efficiency (BTE) when the start of combustion (SOC) occurred near the top dead center (TDC): 32.40% at 1000 bar while G80B20 shows its best enhancement of BTE when the SOC occurs near the top dead center 56.3 % at 800 bar.