Comparative behavior of gasolineediesel/butanolediesel blends and injection strategy management on performance and emissions of a light duty diesel engine Stefano E. Iannuzzi, Gerardo Valentino * Istituto Motori, CNR, Napoli, Italy article info Article history: Received 22 November 2013 Received in revised form 24 March 2014 Accepted 20 April 2014 Available online xxx Keywords: Diesel engine Injection strategy management Butanolediesel blend Gasolineediesel blend PPCI (partial premixed compression ignition) abstract 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 gasolineediesel, butanolediesel 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 man- agement 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 butanolediesel blend gave lower UHC (unburned hydrocarbons) emissions than the diesel and gasolineediesel blend because of the positive role played by the oxygen on the oxidation process. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction To meet the forthcoming severe legislation on emissions, research laboratories and manufacturers are focused on the development of advanced technological systems and innovative combustion mechanisms to reduce pollutant emissions from diesel engines without penalties on performance. Most manufacturers, especially European ones, have opted for the SCR (selective cata- lytic reduction system) and DPF (diesel particulate filter) to reduce NOx and soot, respectively. On the contrary, research institutions are conducting extensive research projects in the area of innovative combustion mechanisms such as HCCI (homogeneous charge compression ignition), LTC (low temperature combustion), SCCI (stratified charge compression ignition) and PPCI (partial premixed compression ignition). In fact, conventional diesel combustion has the unsolved problem of high nitric oxide and particulate matter emissions coming from the heterogeneous airefuel mixing and the complex physical and chemical processes involved during the auto- ignition and the combustion regimes. The conventional compres- sion ignition combustion may be defined as a premixed combustion followed by a mixing-controlled one. Premixed combustion refers to the ignition of the fuel amount injected during the ignition delay interval that mixes with air, evaporates and activates the ignition chemical reactions. This stage has a fast burning rate producing high in-cylinder temperature and pressure peaks with high local concentration of nitric oxides and combustion noise. The mixing- controlled combustion, instead, associated to the fuel injected in the flame front, is characterized by lower heat release peaks with the formation of high soot concentration [1]. Innovative combustion regimes could be the best candidates to solve the NOx (nitrogen oxides) -soot trade-off problem of compression ignition engines and improve efficiency. Until now, innovative combustion regimes (HCCI, SCCI) have suffered from uncontrollable ignition and combustion rates, narrow operating load ranges, high levels of CO (carbon monoxide)and HC (hydro- carbons) emissions, and difficulty in cold start operations. The main idea of these combustion regimes is that ignition and combustion * Corresponding author. E-mail address: g.valentino@im.cnr.it (G. Valentino). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2014.04.065 0360-5442/Ó 2014 Elsevier Ltd. All rights reserved. Energy xxx (2014) 1e11 Please cite this article in press as: Iannuzzi SE, Valentino G, Comparative behavior of gasolineediesel/butanolediesel blends and injection strategy management on performance and emissions of a light duty diesel engine, Energy (2014), http://dx.doi.org/10.1016/ j.energy.2014.04.065