Feasibility Study of an Online Gasoline Fractionating System for use in Spark-Ignition Engines

A fuel fractionating system is designed and commissioned to separate standard gasoline fuel into two components by evaporation. The system is installed on a Ricardo E6 single cylinder research engine for testing purposes.

Laboratory tests are carried out to determine the Research Octane Number (RON) and Motoring Octane Number (MON) of both fuel fractions. Further tests are carried out to characterize Spark-Ignition (SI) and Controlled Auto-Ignition (CAI) combustion under borderline knock conditions, and these are related to results from some primary reference fuels.

SI results indicate that an increase in compression ratio of up to 1.0 may be achieved, along with better charge ignitability if this system is used with a stratified charge combustion regime. CAI results show that the two fuels exhibit similar knock-resistances over a range of operating conditions.