An experimental study was conducted on Rapid Compression and Expansion Machine (RCEM) that have similar characteristic with Compression Ignition (CI) engine for gasoline-biodiesel (GB) blend 10% and 20% by volume with varying fuel injection pressure 800-1400bar. Particularly, the aim was to study the combustion phenomena of Gasoline Compression Ignition (GCI) engine. For the various fuel injection pressure and chosen GB blends fuel. The engine compression ratio was set at 16, 1000 μs of injection duration and 12.5oBTDC Before top dead center. The results show that GB 20 have shorter ignition delay than GB 10, and by increasing the injection pressure make the auto ignition occur faster. Injection pressure also effect on thermal efficiency. Increase injection pressure from 800-1000bar increase the thermal efficiency drastically. But increase injection pressure above 1000bar make thermal efficiency decrease due the constant air capacity.
Keywords rapid compression expansion machine, gasoline compression ignition