Abstract: A method for controlling timing of ignition of a fuel charge in a compression-ignition engine operating in a controlled auto-ignition mode wherein the engine includes controllable intake and exhaust valve actuation systems is described. The method comprises determining a preferred ignition timing for a cylinder charge and a mass of the fuel charge based upon operator torque request. A portion of the fuel charge is partially oxidized during a negative valve overlap period immediately prior to a compression stroke. Magnitude of the portion of the fuel charge is based upon the preferred ignition timing of the cylinder charge. A remainder of the fuel charge is injected into the cylinder during the compression stroke.

Abstract: A method and apparatus are provided for generating a reductant in an exhaust gas feedstream of a compression-ignition internal combustion engine upstream of a hydrocarbon-selective catalytic reduction catalyst. The method comprises injecting a quantity of fuel into the exhaust gas subsequent to a combustion event whereat a temperature of the exhaust gas is in a range of 670 K to 1100 K at a start of the injection. The generated reductant comprises an active species including an oxygenated fuel species.

Abstract: There is provided a method and apparatus for exhaust gas purifying, especially NOx reduction. The apparatus comprises an internal combustion engine adapted to operate primarily lean of stoichiometry. There is an aftertreatment system that is fluidly connected to and adapted to treat exhaust gas flowing from the internal combustion engine. The aftertreatment system comprises a hydrocarbon-selective catalytic reduction device. There is an injector device adapted to inject a blend of fuel and an ignition improver into the exhaust gas at a location upstream of the hydrocarbon-selective catalytic reduction device. A control module is adapted to control the injector device to inject the blended fuel and cetane-enhancer into the exhaust gas when temperature of the exhaust gas at the location of the injection is greater than about 280° C.

Abstract: The invention provides a method for operating a multi-cylinder, spark-ignition, direct-injection, four-stroke internal-combustion engine adapted to operate in a controlled auto-ignition mode selectively operative at stoichiometry and lean of stoichiometry. The method comprises adapting an engine valve actuation system to control engine valve opening and closing, and monitoring engine operating conditions and ambient barometric pressure. The engine is operated unthrottled and the engine valve actuation system is controlled to effect a negative valve overlap period when the engine operating conditions are within predetermined ranges. A mass of fuel is injected during the negative valve overlap period. The magnitude of the negative valve overlap period is decreased with decreasing ambient pressure and increased with increasing ambient pressure.

Abstract: The invention provides a method for operating a multi-cylinder, spark-ignition, direct-injection, four-stroke internal-combustion engine adapted to operate in a controlled auto-ignition mode selectively operative at stoichiometry and lean of stoichiometry. The method comprises adapting an engine valve actuation system to control engine valve opening and closing, and monitoring engine operating conditions and ambient barometric pressure. The engine is operated unthrottled and the engine valve actuation system is controlled to effect a negative valve overlap period when the engine operating conditions are within predetermined ranges. A mass of fuel is injected during the negative valve overlap period. The magnitude of the negative valve overlap period is decreased with decreasing ambient pressure and increased with increasing ambient pressure.

Abstract: A vehicle driven by a homogeneous-charge compression ignition (HCCI) engine includes a fuel supply that supplies a hydrocarbon fuel in a first amount and an acetylene supply that supplies an acetylene-based component in a second amount. A cylinder has a piston reciprocally driven therein. The cylinder receives a combustion mixture including a third amount of air, the first amount of hydrocarbon fuel and the second amount of the acetylene-based component. The piston compresses the combustion mixture to induce auto-ignition of the combustion mixture. The acetylene-based component includes one of acetylene, an acetylene-hydrogen mixture, and a mixture of acetylene, hydrogen and other products of the acetylene production process.