Patent ID: 8082735

Claim:
An engine system comprising: a spark ignition engine; at least one of turbocharger and supercharger for compressing air into said spark ignition engine; a first source of an ethanol-gasoline mixture; a means for directly injecting a liquid ethanol-gasoline mixture from the first source into at least one cylinder of the spark ignition engine; a second source of gasoline; a means for independently controlling fueling the engine with the gasoline from the second source; wherein an energy fraction in the cylinder provided by the directly injected ethanol is at least 20%; and further comprising: wherein under driving conditions, a manifold pressure is greater than 2 bar; wherein during at least part of an operating time under said driving conditions, the engine is operated at a substantially stoichiometric fuel/air ratio; and wherein at a start-up condition, the engine is operated with only the gasoline from the second source.