Effect of exhaust gas recirculation on the performance and emission characteristics of a DI‐CI engine fueled with butanol/diesel blends

Abstract

AbstractThe rapid consumption of fossil fuels, ever rising energy demand, and rigorous emission norms have been attracting the attention of researchers toward clean renewable fuels such as alcohol‐based fuels. Higher chain alcohol fuels are attractive alternative fuels for use in diesel engine. A higher chain alcohol (butanol, pentanol, etc.,) has better blending properties, higher calorific value, and higher cetane number than the lower chain alcohol. Alcohol fuels can be produced from the biomass. Therefore, it is important to examine the fuel, as well as its blends with diesel fuel in diesel engine for the engine characteristics. The present paper aims at studying the performance characteristics of a DI‐CI engine using butanol/diesel (B/D) blends with and without exhaust gas recirculation (EGR). Experiments were performed on a single cylinder CI engine with two different B/D blends (20% and 40% by volume of butanol in the mixture—denoted as a Bu20 and Bu40), with different EGR rates (0%–30% in steps of 10%). The experimental results showed that the brake thermal efficiency (BTE) improved by 1.1% and 1.25% for Bu20 and Bu40 blends in comparison with Bu00. Nitrogen oxides (NOx) emissions reduced by 7.9%, 12.9% for Bu20 and Bu40 blends compared Bu00 respectively. Similarly, the soot emission decreased by 18% and 40.9% for Bu20 and Bu40 compared to Bu00. With the use of EGR, the NOx emissions significantly decreased. At 30% of EGR rate, the NOx emission reduced by 53.9%, 60.2%, and 67% for Bu00, Bu20, and Bu40, respectively. The soot emissions increased slightly at lower EGR rates of 0% to 20%. However, the soot emissions increased drastically at higher EGR rates for all the B/D blends. It is concluded that a combination of higher fraction of B/D blends along with a small EGR rate, can achieve lower emissions (soot and NOx) with a small penalty on the engine performance.