Performance Assessment of a Single-Cylinder Diesel Engine with Diesel and Waste Cooking Oil Blends Preheated by Engine Exhaust Gas

Abstract

The present work explains the engine performance using waste cooking oil (WCO) blended with diesel. The viscosity of WCO can be reduced to be comparable with diesel by preheating at 90°C and thus improves the engine combustion efficiency. For the purpose of preheating, a shell and tube heat exchanger were designed. The optimized tube and shell diameters of the heat exchanger were estimated as 17 and 460 mm, respectively. Pressure drops in tube and shell sides changed from 28.40 - 27.40 Pa and 0.025 - 0.1 Pa respectively. Flue gas energy contents varied from 4000 W to 16000 W at the mass flow rate of 0.03-0.08 kg/s. Useful energy gained by the heat exchanger for waste cooking oil preheating varied from 1200-5500 W at 1200-3000 rpm. Kinematic viscosity for WCO was 51.85 cSt and it changed to 7.55 - 17.5 cSt for blends of 10 - 30% with diesel at 40°C. As the blending % of WCO with diesel increased, there was a minor drop in brake power because of lower calorific value of the mixture. There was a minor increment of torque because of preheating. Preheated fuel blends injection into the cylinder facilitated better fuel efficiency. Minimum and maximum values of exhaust gas temperature were 345°C and 385°C at 1200 and 3000 rpm of engine speeds respectively.