Patent ID: 7703446

Claim:
Engine management system for operation of a direct injection spark ignition gasoline engine comprising: a gasoline engine; a source of gasoline; a source of anti-knock agent; a first low pressure pump for pumping gasoline for the source of gasoline; a second low pressure pump for pumping anti-knock agent from the source of anti-knock agent; a high pressure pump; a proportioning valve for receiving gasoline and anti-knock agent from the first and second low pressure pumps and delivering a selected mixture of gasoline/anti-knock agent to the high pressure pump; at least one injector for receiving the selected mixture from the high pressure pump and directly delivering the liquid mixture into a cylinder of the engine where the ratio of the anti-knock agent to gasoline is sufficient to prevent knock as the torque is increased and where the volume between the high pressure pump and the fuel injectors is minimized to improve transient performance; and wherein when demand exists for direct injection of the antiknock agent, the direct injector first injects mainly the anti-knock agent from a fuel rail/injector that has been primed from the source of anti-knock agent and, over a longer period of time, co-injects gasoline so as to minimize anti-knock agent use, while also providing a fast response in the injection of the anti-knock agent.