Experimental Analysis of Combustion and Emission Characteristics of a Diesel Engine Using Diesel‐Biodiesel‐Methanol Blends With Cetane Enhancer Additive Under Pilot Injection Mode

ABSTRACT The presented work explores diesel pilot injection (PI) mode with a prime objective of resolving the inherent problem of increased smoke emissions associated with it. The problem of greater smoke emissions under PI mode was addressed by using methanol and a cetane enhancer (CE) with the base fuel. PI mode was investigated by varying pilot injection timing (PIT) as well as pilot injection ratio (PIR) using B30 (30% Biodiesel + 70% Diesel) as a base fuel and single injection (SI) mode with the base fuel served as a reference condition. The biodiesel for the presented study was derived from the waste cooking oil using standard transesterfication process. Methanol was added by 10% volume into B30 to prepare M10 blend and A1 blend was prepared by adding 0.5% volume of di‐tert‐butyl peroxide (DTBP) which is a CE into M10 blend. Experiments were performed using an automotive diesel engine which was operated at rated torque speed (1600 rpm) and 90% of full load conditions. The results demonstrated that A1 blend with 10% PIR and −30° after top dead center PIT improved fuel consumption and thermal efficiency by 8.77% and 13.77% respectively compared to reference condition along with offering reduction in carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC) emissions by 66.66%, 6.43%, and 8.11% respectively while increasing smoke emissions just by 2.65%.