Patent ID: 7685996

Claim:
An internal combustion engine system, comprising: an engine cylinder; a direct injector coupled to said cylinder; a port injector coupled to an engine intake, said engine intake communicating with said cylinder via an intake valve; and an electronic control unit electronically coupled to the engine, said port injector, and said direct injector, said electronic control unit determining whether pre-ignition is occurring and in response to occurrence of pre-ignition adjusting injection timing of said direct injector toward a time when a piston in said cylinder is nearest said injector to cause fuel from said direct injector to impact a top of said piston wherein said direct injector supplies fuel with greater than 75% alcohol content and said port injector supplies fuel with less than 15% alcohol content and said electronic control unit increasing an amount of fuel supplied by said port injector and decreasing an amount of fuel supplied by said direct injector in response to pre-ignition in said cylinder.