Effect of piston bowl geometry on diesel engine performance operated with dairy scum biodiesel

Abstract

ABSTRACT A sincere effort towards conversion and utilisation of any locally available bio-waste as alternative fuels for the internal combustion engine is most required nowadays. However, diesel engine parameters are more attuned with diesel fuel operation. In this regard, optimisation of piston bowl geometry is highly distinct to improve the substandard performance of the biodiesel operated diesel engine. In the present study, existing diesel engine hemispherical piston bowl geometry (HPBG) is modified into toroidal piston bowl geometry (TPBG) to evaluate the diesel engine performance operated with 20% dairy scum biodiesel (B20). The TPBG-ME operation has shown 6.50% of increased brake thermal efficiency, 17.24% of increased heat release rate, 1.97% of increased cylinder pressure, 3.92% of increased pressure rise rate 8.75% of reduced brake-specific fuel consumption, 15% of lowered HC emission, 8.33% of reduced ignition delay and 11.36% of decreased combustion duration when compared with the standard engine with piston HPBG run with B20 fuel blend (DSOME-B20-SE). Abbreviations: BSFC: Brake-specific fuel consumption (kg/KW h); bTDC: Before top dead centre (°CA); BTE: Brake thermal efficiency (%); CC: Combustion chamber; CHRR: Cumulative heat release rate (J/°CA); CO: Carbon monoxide (%); CO2: Carbon dioxide (%); CR: Compression ratio; deg.: Degrees; Diesel-SE: Diesel operated standard engine; DSOME: Dairy scum oil methyl ester; DSOME-B20: 20% dairy scum biodiesel + 80% Diesel (B20); DSOME-B20-SE: 20% dairy biodiesel operated standard engine (B20-SE); EGR: Exhaust gas recirculation; HC: Hydrocarbons; HPBG: Hemispherical piston bowl geometry; HPBG-ME: Modified engine with HPBG piston; HRR: Heat release rate; HS: High speed; IDP: Ignition delay period; IOP: Injector opening pressure; IT: Injection timing; KOH: Potassium hydroxide; kW: Kilo watt; ME: Modified engine; NH: Nozzle hole; NOx: Oxides of nitrogen; SE: Standard engine; TKE: Turbulent kinetic energy; TPBG: Toroidal piston bowl geometry; TPBG-ME: Modified engine with TPBG piston; TRCC: Toroidal combustion chamber; ULSD: Ultra low sulphur diesel