Effect of biodiesel-dimethyl carbonate blends on engine performance, combustion and emission characteristics

Present study investigates the effect of palm biodiesel blends with and without oxygenated alcohol dimethyl carbonate (DMC) on compression ignition engine. H2SO4 was used to treat the crude palm oil. Furthermore, acid treated palm oil was converted into palm biodiesel via ultrasound-assisted transesterification process at operating conditions of catalyst (KOH) concentration of 0.75 wt%, methanol to oil ratio of 60 V/V %, reaction time of 38 min, reaction temperature of 60 °C and 59% duty cycle. The antioxidant used in biodiesel blends was dimethyl carbonate. These samples were prepared by adding DMC 10% by volume into biodiesel blends at stirring speed of 2000 rpm for 30 min in order to make a homogenous blend. The key fuel properties of the six fuel samples before being engine tested were measured including kinematic viscosity, dynamic viscosity, density, flash point, acid value and calorific value. Engine performance, emission and combustion characteristics were investigated by operating engine at full load condition and varying engine speeds from 1100 rpm to 2100 rpm. Major findings were average increase of 1.70%, 1.22% and 0.95% in BP; average decrease of 1.31%, 2.93% and 1.08% in BSFC; average increase of 4.30%, 4.77% and 4.90% in BTE; average decrease of 2.63%, 2.80% and 4.54% in EGT; significant reduction of 19.04%, 25% and 26.47% in CO emissions; average reduction of 12.76%, 19.35% and 33.33% in HC emissions observed for B10 + DMC, B20 + DMC and B30 + DMC as compared to biodiesel blends without antioxidant.