Abstract: A number of systems and methods are disclosed which increase the replenishment interval for anti-knock fluid. This is especially important during activities which require a large amount of anti-knock fluid, such as towing. In some embodiments, the systems and methods are used to reduce anti-knock fluid consumption. For example, changes to engine operation, such as rich operation, spark retarding, upspeeding, and variable valve timing, all serve to reduce the amount of anti-knock fluid required to eliminate knocking. In other embodiments, the composition of the anti-knock fluid is modified, such as by using a higher octane fluid, or through the addition of water to the anti-knock fluid. In other embodiments, the replenishment interval is increased through a larger anti-knock fluid storage capacity. In one embodiment, a three tank system is used where the third tank can be used to store gasoline or anti-knock fluid, depending on the driving conditions.

Abstract: Engine management system for operation of a direct injection spark ignition gasoline engine. The system includes a gasoline engine, a source of gasoline and a source of an anti-knock agent. Gasoline and anti-knock agent are introduced into a proportioning valve that delivers a selected mixture of gasoline/anti-knock agent to a high pressure pump. At least one injector receives the selected mixture from the high pressure pump and delivers the mixture into a cylinder of the engine. The engine management system provides a rapidly variable mixture of directly injected anti-knock agent and gasoline which prevents knock as the engine torque increases.

Abstract: Fuel tank system for a direct ethanol injection octane boosted gasoline engine. The system includes a gasoline engine and a main fuel tank that contains a mix of gasoline and gasoline E85. A smaller secondary tank is provided to contain ethanol or E85. An injector directly injects in a separately controlled fashion ethanol or E85 into a cylinder of the engine to boost octane. A control module controls the relative amounts of gasoline and ethanol used and structure is provided for fueling the main and secondary fuel tanks.

Abstract: Engine management system for operation of a direct injection spark ignition gasoline engine. The system includes a gasoline engine, a source of gasoline and a source of an anti-knock agent. Gasoline and anti-knock agent are introduced into a proportioning valve that delivers a selected mixture of gasoline/anti-knock agent to a high pressure pump. At least one injector receives the selected mixture from the high pressure pump and delivers the mixture into a cylinder of the engine. The engine management system provides a rapidly variable mixture of directly injected anti-knock agent and gasoline which prevents knock as the engine torque increases.

Abstract: As one embodiment, a method of operating an engine of a vehicle is provided wherein the engine has a variable engine output. The method comprises during a first engine output, delivering a first fuel to at least a cylinder of the engine via a first injector and directly injecting a second fuel directly into said cylinder via a second injector; and during a second engine output lower than said first engine output, delivering said first fuel to said at least a cylinder of the engine via said first injector and directly injecting at least a purging substance via said second injector based on an idle period since a previous injection by said second injector.

Abstract: Fuel management system for operation of a spark ignition engine. The system includes a source of gasoline and a source of anti-knock fuel. A proportioning valve receives the gasoline and the anti-knock fuel to discharge a mixture having a controlled gasoline/anti-knock fuel ratio. A single high pressure pump receives the mixture and delivers the mixture to an injector. A fuel management control system controls the proportioning valve and the injector for injection of the mixture into a cylinder of the engine to control knock. A preferred anti-knock fuel is ethanol.

Abstract: Fuel management system for operation of a spark ignition gasoline engine. The system includes a gasoline engine powering the vehicle and a source of gasoline for introduction into the engine. A source of an anti-knock fuel such as ethanol is provided. An injector directly injects the anti-knock fuel into a cylinder of the engine and the control system shuts down the engine by stopping gasoline and anti-knock agent flow into the engine during vehicle deceleration and idling and restarts the engine upon driver demand. Direct ethanol injection and engine shutdown results in efficiencies similar to those of full hybrid vehicles.