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 efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency of the engine.

Abstract: Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

Abstract: A hydrogen enhanced engine system using high compression ratio is optimized to minimize NOx emissions, exhaust aftertreatment catalyst requirements, hydrogen requirements, engine efficiency and cost. In one mode of operation the engine is operated very lean (equivalence ratio ?=0.4 to 0.7) at lower levels of power. Very lean operation reduces NOx to very low levels. A control system is used to increase equivalence ratio at increased torque or power requirements while avoiding the knock that would be produced by high compression ratio operation. The increased equivalence ratio reduces the amount of hydrogen required to extend the lean limit in order to avoid misfire and increases torque and power. The engine may be naturally aspirated, turbocharged, or supercharged.

Abstract: High compression ratio, homogeneous charge compression ignition engines. In one aspect the engine is dual mode utilizing spark ignition at high load levels including the addition of hydrogen or a hydrogen/carbon monoxide mixture. In another aspect, the engine operates on a high cetane fuel with the addition of hydrogen or a hydrogen/carbon monoxide mixture at low-to-mid-load levels.

Abstract: A hydrogen enhanced engine system using high compression ratio is optimized to minimize NOx emissions, exhaust aftertreatment catalyst requirements, hydrogen requirements, engine efficiency and cost. In one mode of operation the engine is operated very lean (equivalence ratio ø=0.4 to 0.7) at lower levels of power. Very lean operation reduces NOx to very low levels. A control system is used to increase equivalence ratio at increased torque or power requirements while avoiding the knock that would be produced by high compression ratio operation. The increased equivalence ratio reduces the amount of hydrogen required to extend the lean limit in order to avoid misfire and increases torque and power. The engine may be naturally aspirated, turbocharged, or supercharged.

Abstract: A method for reducing required octane number and a spark ignition gasoline engine system with hydrogen-enhanced knock resistance. The method for reducing required octane number of gasoline needed to prevent knock includes the addition of hydrogen or hydrogen-rich gas containing carbon monoxide to gasoline. Octane number can be improved by 5 or more for a hydrogen energy fraction of 10%. The spark ignition gasoline engine system includes a spark ignition gasoline engine and a source of gasoline and hydrogen or hydrogen-rich gas. Apparatus is provided to supply the gasoline and the hydrogen or hydrogen-rich gas to the engine at a varying hydrogen or hydrogen-rich gas to gasoline ratio selected both to prevent knock and to ensure a desired level of combustion stability throughout a full range of engine operation. The engine system may be normally aspirated or boosted; the compression ratio may be high such as greater than 11 or below 11, and EGR may be added.

Abstract: A hydrogen enhanced gasoline engine system using high compression ratio is optimized to minimize NOx emissions, exhaust aftertreatment catalyst requirements, hydrogen requirements, engine efficiency and cost. In one mode of operation the engine is operated very lean (equivalence ratio ø=0.4 to 0.7) at lower levels of power. Very lean operation reduces NOx to very low levels. A control system is used to increase equivalence ratio at increased torque or power requirements while avoiding the knock that would be produced by high compression ratio operation. The increased equivalence ratio reduces the amount of hydrogen required to extend the lean limit in order to avoid misfire and increases torque and power. The engine may be naturally aspirated, turbocharged, or supercharged.

Abstract: A hydrogen enhanced gasoline engine system using high compression ratio is optimized to minimize NOx emissions, exhaust aftertreatment catalyst requirements, hydrogen requirements, engine efficiency and cost. In one mode of operation the engine is operated very lean (equivalence ratio ø=0.4 to 0.7) at lower levels of power. Very lean operation reduces NOx to very low levels. A control system is used to increase equivalence ratio at increased torque or power requirements while avoiding the knock that would be produced by high compression ratio operation. The increased equivalence ratio reduces the amount of hydrogen required to extend the lean limit in order to avoid misfire and increases torque and power. Reduced hydrogen requirements at high power can significantly reduce the cost and size of onboard hydrogen generator technology. Increased in-cylinder turbulence and stratified hydrogen injection can be used to minimize hydrogen requirements for operation at a given equivalence ratio value.