A SPARK IGNITION ENGINE THAT USES INTAKE PORT INJECTION OF ALCOHOL TO EXTEND KNOCK LIMITS

摘要

Internal combustion engine system. The system includes a source of gasoline for direct injection into cylinders (20) of a spark ignition engine along with a source of an antiknock fuel for injection into the intake ports (14) of the engine as needed to prevent knock. A preferred antiknock fuel is ethanol or an ethanol / gasoline blend having an ethanol content of 20% by volume or more. Other suitable antiknock fuels are methanol, a combination of ethanol and methanol, and a blend of gasoline with either ethanol, methanol, or an ethanol / methanol mixture.