Impact of fuel injection pressure on the engine characteristics of CRDI engine powered by pine oil biodiesel blend

Abstract

Optimization of fuel injection strategies can maximize the utilization of biodiesel by addressing the issues concern with fuel consumption, engine performance, and exhaust gas emission. In the midst of the pervasiveness of plant-based biofuel, this paper focused on maximizing the pine oil biodiesel usage in a diesel engine having common rail direct injection (CRDI) system without any engine modifications. Pine oil derived from pine tree resins, has shown impressive fuel properties such as lower viscosity, flash point, boiling point and comparable calorific value to diesel. In this study, the impact of high fuel injection pressure on the engine characteristics of a diesel engine fueled by 30% pine oil biodiesel blend (P30) was analyzed. At standard 200 bar fuel injection pressure, the brake thermal efficiency (BTE) of P30 biodiesel blend was decreased compared to sole diesel. To improve the utilization and performance of the P30 blend, fuel injection pressure increased from 200 bar to 350 bar at a step of 50 bar. The results show that BTE and combustion characteristics are improved with an increase in injection pressure. The P30 fuel exhibits maximum BTE of 26.1% at 350 bar which is 6.9% higher the BTE of diesel at 200 bar. Exhaust emissions (CO, HC & Smoke) decreased gradually with increase in fuel injection pressure due to high atomization of fuel, faster evaporation, and formation of the better air fuel mixture. At 100% load condition, the P30 blend shows a maximum decrease in CO and HC emission at 300 bar, which is 16.6% and 13.1% less respectively compared to sole diesel at 200 bar injection pressure. The NOx is increased by about 9.4% for P30 blend at 350 bar when compared to that of Diesel at 200 bar. Thus, the blending ratio of pine oil biodiesel in the diesel can be extended by increasing the fuel injection pressure.