Effects of dilute gas on combustion and emission characteristics of a common-rail diesel engine fueled with isopropanol-butanol-ethanol and diesel blends

Abstract

Isopropanol-butanol-ethanol (IBE) can be used in engines as an alternative fuel to eliminate the high recovery and separation costs in the production of butanol and also to avoid the corrosivity and low flash point of acetone in acetone-butanol-ethanol (ABE). In this respect, this study is aimed to investigate the performance, combustion and emissions of a single-cylinder, common-rail diesel engine fueled with IBE and diesel blends. Two blends of butanol and diesel fuel, denoted as IBE15 (15% IBE and 85% diesel in volume) and IBE30 (30% IBE and 70% diesel in volume) were tested. Additionally, the experiments in this study were conducted at different diluted gas ratios to achieve low NOx emission. The experimental results show that when the intake charger is gradually diluted, the start of combustion and combustion center for all the tested fuels are remarkably delayed. Compared with pure diesel, the brake thermal efficiency (BTE) for IBE15 is always higher. Butt for IBE30, the BTE is lower than that of pure diesel when the flow rate of the dilute gas is less than 30 L/min. For all the tested fuels, NOx emission reduces while CO and HC emissions increase with the increase of dilute gas. Soot emission for pure diesel and IBE15 drastically increases as the dilute gas increases. However, the increase of dilute gas does not cause the soot emission of IBE30 to significant increase. That is to say, IBE30 coupled with a proper EGR ratio has the potential to reduce NOx and soot emissions simultaneously.