Effect of pilot injection timing using crude palm oil biodiesel on combustion process on dual fuel engines with compressed natural gas as the main fuel

The availability of liquid fossil fuels is dwindling. Alternative fuels for CNG and CPO biodiesel that can be used in DF engines are the solution. However, the use of this fuel has reduced engine performance and increased CO and HC emissions. In addition, the use of CPO biodiesel as fuel for ignition in the DF engine is a parameter that has not been developed in previous studies so that it requires adjustment of engine parameter under standard conditions. Pilot injection timing (PIT) is critical in starting combustion in sequential combustion models of DF engine. This study aims to determine the effect of PIT using CPO biodiesel fuel on increasing engine performance and reducing emissions, so that this parameter becomes important. The PIT parameter was varied from 11° to 19° BTDC with 2° intervals at different engine loads on a DF engine. The results showed that CPO biodiesel is an effective pilot fuel in DF engine. PIT has a significant effect on increasing engine performance and reducing emissions. Increased thermal efficiency by 8.87% and HRR by 7.34%, while SFC emissions, CO emissions and HC emissions decreased by 43.85% and 25.33% respectively with a PIT of 15° BTDC at high load.