Furans such as 2-Methylfuran (2-MF) and 2,5-Dimethyulfuran (DMF) are not popular fuels so far. But they can be derived from biomass via sugars and have preferable fuel properties for spark ignition engines. In this work, the effect of furans on knock suppression was investigated. Firstly, auto-ignition delay of 2-MF blend fuel was compared with other biofuel blends such as ethanol and toluene blend known as high octane number fuel by using a rapid compression expansion machine. 2-MF suppressed cool flame reaction most effectively among tested fuels. As the result, auto-ignition delay of 2-MF blend fuel was quite longer than ethanol or toluene blend in spite of the fact that pure 2-MF had lower octane number and higher ignitability. Secondly, the impact of knock suppression was confirmed using a single cylinder research engine. The lower the RON of base fuel was, the higher the blending octane number was, when the base fuel was paraffin mixture.
