Experimental investigation of butanol isomers as fuel in a dual fuel diesel engine

Fossil-based fuels used in internal combustion engines are not only at risk of depletion but also controversial due to their high pollutant emissions. Diesel engines, in particular, produce hazardous emissions, limiting their usage. Researchers are actively investigating alternative fuels and combustion strategies to address these issues. This thesis explores the combustion characteristics and pollutant emissions in a diesel engine using alternative fuels and a dual-fuel strategy. Experiments were conducted on a single-cylinder, air-cooled diesel engine equipped with a common rail fuel injection system, operating at a constant speed of 2400 RPM and a fixed load of 50%. The alternative fuels chosen were the butanol isomers: n-butanol, iso-butanol, sec-butanol, and tert-butanol, with the aim of conducting a comprehensive study on butanol, a promising alternative fuel in recent years. In the dual-fuel combustion strategy, diesel fuel was directly injected into the cylinder, while the secondary fuel (butanol) was introduced at the beginning of the intake stroke using port injection. Tests were repeated for mixture ratios of 15%, 30%, and 45% of the butanol isomers. The results of utilizing butanol isomers in a diesel engine with a dual-fuel strategy are presented in detail. The combustion characteristics and pollutant emissions are discussed based on the study parameters. It was observed that the dual-fuel strategy using butanol isomers did not significantly compromise engine performance, significantly reduced smoke opacity, and concurrently decreased NOx emissions at lower mixture ratios.