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

## TL;DR

This study investigates how adding methanol and a cetane enhancer to diesel-biodiesel blends can reduce smoke emissions in diesel engines while maintaining fuel efficiency and lower NOx emissions.

## Contribution

The novel approach of using methanol and a cetane enhancer in pilot injection mode to reduce smoke emissions in diesel engines is introduced.

## Key findings

- A1 blend with 10% PIR and -30° PIT improved fuel consumption and thermal efficiency by 8.77% and 13.77% respectively.
- CO, NOx, and HC emissions were reduced by 66.66%, 6.43%, and 8.11% respectively with only a 2.65% increase in smoke emissions.

## 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%.

The work represented in the manuscript is based on resolving the major issue of increased smoke emissions under pilot injection mode while maintaining the core benfits of it, that is, lower nitrogen oxides (NOx) emissions and improved fuel economy. This was achieved by inclusion of methanol and cetane enhancer (CE) in the base fuel.