Review on the combustion progress and engine application of tailor-made fuels from biomass

The Tailor-made Fuels from Biomass (TMFB) project aims to develop renewable and environmentally friendly fuels suitable for internal combustion engines (ICEs). The TMFB fuels can be produced from lignocellulose, helping to avoid land competition with edible food for production. After years of research, 2-butanone, 2-methylfuran (2-MF), 2-methyltetrahydrofuran (2-MTHF), n-octanol, and di-n-butyl ether (DnBE), have been identified as the promising TMFB fuels that are suitable for ICEs. This paper first discusses the physicochemical properties of the above five fuels. It then reviews the experimentally measured fundamental combustion characteristics, including ignition delay and flame speed. In addition, progress in detailed chemical kinetic modeling of the TMFB fuels is also presented individually. These models are validated against measured experimental ignition delay or flame speed data. The reaction pathway analysis for the five fuels can be performed based on these validated kinetic models. Next, the effects of the above five TMFB fuels on the combustion and emission characteristics of ICEs are summarized. 2-Butanone and 2-MF can be used as gasoline replacement fuels for spark ignition engines. 2-MF and 2-MTHF can be used in compression ignition engines by blending with highly reactive fuels. N-octanol and DnBE are isomers and can be used either alone or as blended fuels for compression ignition engines. Both the advantages and disadvantages of the above-mentioned fuels used in ICEs have been discussed in this paper. Finally, the remaining research gaps in fundamental combustion characteristics and engine applications are discussed to guide future research directions.