MEASUREMENT OF PERFORMANCE AND EMISSION CHARACTERISTICS OF A 611cc DIESEL ENGINE FUELLED WITH BIODIESEL-ETHANOL-DTBP BLENDS

Abstract

This experimental study target on to increase the use of Waste Cooking Oil (WCO) biodiesel in the engine replacing fossil diesel fuel. Effect of peroxy fuel additive DTBP (Di-tert butyl peroxide) in biodiesel (primary fuel) blended with different concentration 1.2 % to 2.4 % by volume are studied. Furthermore, ethanol up to 10 % in biodiesel-DTBP blends are also added. Biodiesel alone in 611cc single cylinder diesel engine without any modification produced higher NOx (nitrogen oxides) due to prolonged ignition delay. This prolonged ignition delay and higher peak heat release rate result of fuel properties like viscosity, density, chemical structure, cetane number. Due to higher molecular mass and improper mixing of biodiesel with air formed HC (hydrocarbon) and CO (carbon monoxide) emission similar to that of diesel emissions. To improve ignition quality, reduce NOx formation and enhance combustion efficiency DTBP added in the different proposition. An addition of 1.6 % DTBP with 98.4 % biodiesel by volume used in a diesel engine, up to 9.5 % decrease in NOx was measured. Reduction in HC, CO and smoke emission by 31 %, 33 %, and 31 % were measured too. This blend gives excess oxygen at exhaust compared to diesel and biodiesel alone in the engine. An addition of 5 % DTBP with 95 % biodiesel by volume used in a diesel engine, the atmospheric oxygen content in exhaust increase from 12% to 12.5 %. Excess oxygen in exhaust shows that the biodiesel uses additive’s oxygen in the early stage of combustion. Further investigation showed 5 % addition of ethanol in biodiesel with ignition promoter DTBP led to lowering the emissions. An addition of 5 % ethanol, 1.8 % DTBP with 93.2 % biodiesel by volume used in a diesel engine, up to 14 % decrease in NOx was measured. Fuel blending with ethanol also showed a reduction in HC, CO and smoke emission by 44 %, 44 %, and 39 % respectively. Engine performance also improved with the use of DTBP additive in biodiesel and ethanol blends.