A comparative study of engine performance and emission characteristics of biodiesels produced from the waste seeds of papaya and stone fruit

This paper investigates the engine performance and emission characteristics of the biodiesels synthesised from papaya seed oil (PSO), stone fruit kernel oil (SFO) blends using a diesel engine. All experiments were carried out at full load condition with different engine speeds ranging from 1200 rpm to 2400 rpm at an interval of 200 rpm. Diesel (100%) and its four blends such as 10% biodiesel with 90% diesel (PSO10, SFO10), and 20% biodiesel with 80% diesel (PSO20, SFO20) were considered for comparative analysis. Engine performance results showed that the SFO biodiesel blends differed marginally (0.6% triangle Brake Power (BP), 0.3% triangle torque, 3% triangle Brake thermal efficiency (BTE) and 2.3% (sic)Brake specific fuel consumption (BSFC) from PSO biodiesel blends. However, SFO biodiesel blends produced higher exhaust emissions than PSO biodiesel blends, in the order of 2.1% triangle NOx, 3% triangle PM, 10.1% triangle HC, 5.4% triangle CO2, and 13.3% triangle CO. Both biodiesel blends produced considerably reduced emissions of PM (max. 34%), HC (max. 33%), and CO (max. 31%) as compared to diesel, while a slight in NOx (max. 6.8%) and CO2 (max. 8.7%) was observed. These results demonstrate that both SFO and PSO could be effectively used in a diesel engine without any modifications.