Patent ID: 7370609

Claim:
An internal combustion engine system which can switch back and forth between spark ignition combustion and homogeneous charge compression ignition combustion, comprising: a fuel tank that accommodates a blended fuel having a research octane number of 80 to 100, which has been prepared by blending gasoline having the research octane number of 30 to 85 and ethanol into a weight ratio between 9:1 and 6:4; a separating means for adding water to the blended fuel to separate the blended fuel into the gasoline and an ethanol-water mixture liquid; a reforming means for extracting one part of the ethanol-water mixture liquid, and reforming ethanol contained in the ethanol-water mixture liquid into diethyl ether to produce a mixture liquid of diethyl ether and water; and respective fuel injectors which independently inject the gasoline, the ethanol-water mixture liquid and the mixture liquid of diethyl ether and water.