Given that the issue related to the high cost of butanol would beavoided if ABE could be directly used for clean combustion, the interest in ABE as an alternative fuel has recently increased. Chang et al. [19] investigated a series of water-containing ABE–diesel blends in an engine. It was found that a diesel mixed with 20 vol. % ABE and 0.5 vol.% water enhanced the BTE by 3.26–8.56%. In addition, the emissions of particular matter, polycyclic aromatic hydrocarbons and NOx could be simultaneously reduced compared to diesel.