Comparative behavior of gasoline-diesel/butanol-diesel blends and injection strategy management on performance and emissions of a light duty diesel engine

Biodiesel or oxygenated fuel from renewable sources set a challenge to the engine technology to design relevant systems for keeping high efficiency and low environmental impact. The objective of this paper was to investigate the influence on combustion and emissions in a Euro 5 light duty diesel engine fueled with gasoline-diesel, butanol-diesel and commercial diesel fuels. Engine tests were carried out 2500 rpm and 0.8 MPa of brake mean effective pressure. The investigation was focused on the management of injection strategy for different combustion phasing under two oxygen concentrations at intake. The main results showed that the longer ignition delay and better volatility provided by the gasoline and butanol blends activated a premixed combustion mechanism for the single injection strategy, which helped to enhance the air/fuel mixing with benefits on smoke and NOx (nitrogen oxides) emissions. For the butanol-diesel blend, favorable effects on soot were also strengthened by the presence of O-2 within the butanol molecule that plays a positive role on the reduction of local rich fuel regions and on soot formation and oxidation. The butanol-diesel blend gave lower UHC (unburned hydrocarbons) emissions than the diesel and gasoline-diesel blend because of the positive role played by the oxygen on the oxidation process. (C) 2014 Elsevier Ltd. All rights reserved.