Performance and Emission Analysis of a CI Engine Fueled with Preheated Neem Straight Vegetable Oil-Diesel Blend at Various Compression Ratios

Abstract

The twin crisis, fast depletion of limited conventional fuel and environment degradation due to these fuels created a dire need to search for clean, green and sustainable alternatives to conventional fuels. Neem vegetable oil may be an alternative of conventional petroleum fuels due to its abundant availability in India and comparable physical and chemical properties. In the present study, performance and emission characteristics of VCR diesel Engine were observed using preheated and blended straight Neem oil. Initially experimentation was carried out to optimize the neem oil blend at engine optimize conditions which was given by manufacturer but this part is not considered in this research paper. Optimize Neem oil blend B30 (30% Neem oil and 70% Diesel) was used as fuel in the current study. Heat exchanger was design and developed to preheat the blended Neem oil up to 90 to 100 °C using engine exhaust gases. This temperature is sufficient to bring viscosity of blended Neem oil about viscosity of diesel. Performance emission characteristics of diesel engine were evaluated at compression ratios 18, 19, 20, 21 and 22. It was observed that at compression ratio 22, brake thermal efficiency of the engine was found optimum 34.99% using preheated optimum blend B30 which was higher than other compression ratios, diesel (1.64%) and unheated optimized same blend (5.07%). Less emission was observed for pre heated optimized blend B-30 as compared to other compression ratios, diesel and optimized same blend. Smoke opacity, CO, HC, NOx emissions at CR 22 for preheated NOB30 observed lowest 33%, 0.15%, 20 PPM and 340 PPM at full load condition.