Nov 3, 2015 - Biofuels, also referred to as renewable fuels, have the potential to be the sustainable energy source for mobi- lity via the internal combustion ...
Special Issue Editorial International J of Engine Research 2015, Vol. 16(5) 609 Ó IMechE 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1468087415597824 jer.sagepub.com
Editorial: Biofuels in internal combustion engines
Biofuels, also referred to as renewable fuels, have the potential to be the sustainable energy source for mobility via the internal combustion (IC) engines. The premise is that the fuel is made from plants, for which the carbon content is derived from the CO2 in the atmosphere so that the fuel carbon does not contribute to net CO2 emission. Bio-ethanol, bio-diesel, bio-gas, and others are produced from different renewable energy crops or waste biomass, with different fuel properties. Biofuels are increasingly applied worldwide in IC engines as alternative, non-petroleum-based fuels, in neat form, or as blends with conventional fuels. The drive to biofuels is due to the gradual reduction of petroleum reserves, to increasing fuel prices, and to environmental concerns about global warming. More than 50 countries worldwide have biofuel mandates in place. Several forecasts are available about the global growth of biofuel production, in the range of 1%–3.5% depending on the country. Currently, the majority of the biofuels comprises ethanol and biodiesels from crops. Intense developments are being conducted on making the second-generation biofuels from non-crop plants. Each biofuel has unique physical and chemical properties which render new opportunities in engine applications. The resulting combustion behaviors in spark ignition (SI), compression ignition, and dual-fuel engines, and in engines implementing innovative combustion modes, are extremely important, in terms of energy conversion efficiencies and emissions. Intensive research and development work is currently under progress, by means of both experimental and numerical techniques, to investigate and optimize in-cylinder processes such as injection, mixture formation, and combustion and to enhance the existing after-treatment technologies for biofuel application. To address the importance of biofuels, this Special Issue includes seven articles that cover several topics related to biofuel application in IC engines. The physical properties of the biofuel impact the mixture preparation process and thus the combustion. The first article by Keller et al. addresses the topic of differential evaporation of biofuels to determine the
effects of different component volatility on the species evaporation history and the resulting spray pattern. Different biofuel formulations offer opportunities to optimize the fuel characteristics for injection and combustion. The second article, by Heuser et al., investigates the combustion and emission behaviors of linear C8-oxygenates derived from (hemi-)cellulose by selective catalytic conversion. The next four articles address the impact of biofuels on different engine configurations. A dual-fuel engine is investigated in the article by Han et al. with intake port injection for ethanol and with the ignition source provided by directly injected diesel fuel. The role of piston bowl geometry in diesel engines fueled with biodiesel is studied by Kim et al. via injection visualization experiments and three-dimensional (3D) computational fluid dynamics (CFD) simulation. The use of waste cooking oil bio-diesel fuel in a common rail direct injection engine has been investigated by Hwang et al. with attention to the nature of the particulate matter. Di Iorio et al. report on a comprehensive study of the effects of ethanol/gasoline blends in port fuel injection and direct injection SI engines and of different biodiesels in compression ignition engines. Finally, in their article, Farshad et al. discuss the results of an exergetic and economic analysis of a diesel engine fueled with castor oil bio-diesel using a second law analysis of the engine data and considering emissions, fuel cost, fuel consumption, and engine power loss. The editors of this Special Issue are grateful to the authors for their excellent articles, to the reviewers for their timely effort and useful suggestions, fundamental to achieve the high quality of the articles, and to the International Journal of Engine Research (IJER) editorial and production staff. Wai K Cheng Massachusetts Institute of Technology, USA
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Angelo Onorati Politecnico di Milano, Italy
