Gm Global Technolgoy Operations, Inc.

Thompson M Sloane

Paul M Najt

Kevin L Perry

Jong H Lee

Wei Ping Li

Michael B Viola

Tang-Wei Kuo

Steven Jeffrey Schmieg

David J Cleary

Kushal Narayanaswamy

Shi-Wai S Cheng

Norman Dale Brinkman

David L Hilden

Patricia A Mulawa

Jun-Mo Kang

Chang H Kim

Barry L Brown

David R Monroe

Ping-Ho Tsai

James Donald Smith

Hardo Barths

A powertrain includes an internal combustion engine having a combustion chamber and an aftertreatment system. A method for reducing NOx emissions in the powertrain includes monitoring an actual exhaust gas feedstream ratio of NOto NO, monitoring a desired exhaust gas feedstream ratio of NOto NO, comparing the actual and the desired exhaust gas feedstream ratios of NOto NO, and selectively initiating a NOgeneration cycle based upon the comparison of the actual and the desired exhaust gas feedstream ratios of NOto NO comprising injecting fuel mass into the combustion chamber after a primary combustion event.

Methods for engine exhaust NOx control using no oxidation in the engine

A method for monitoring a hydrocarbon-selective catalytic reactor device of an exhaust aftertreatment system of an internal combustion engine operating lean of stoichiometry includes injecting a reductant into an exhaust gas feedstream upstream of the hydrocarbon-selective catalytic reactor device at a predetermined mass flowrate of the reductant, and determining a space velocity associated with a predetermined forward portion of the hydrocarbon-selective catalytic reactor device. When the space velocity exceeds a predetermined threshold space velocity, a temperature differential across the predetermined forward portion of the hydrocarbon-selective catalytic reactor device is determined, and a threshold temperature as a function of the space velocity and the mass flowrate of the reductant is determined. If the temperature differential across the predetermined forward portion of the hydrocarbon-selective catalytic reactor device is below the threshold temperature, operation of the engine is controlled to regenerate the hydrocarbon-selective catalytic reactor device.

Method and apparatus for monitoring a hydrocarbon-selective catalytic reduction device

Exhaust emissions from a spark-ignition direct-injection engine connected to an oxidation catalytic device and a selective catalyst reduction device having a capacity to store ammonia reductant are controlled. The engine operates in a first combustion mode to generate ammonia reductant, stored on the second aftertreatment device. The engine operates lean of stoichiometry and nitrides of oxygen in the exhaust gas feedstream are reduced on the second aftertreatment device.

Method and apparatus for controlling exhaust emissions in a spark-ignition direct-injection engine

A method for supplying reductant into an exhaust gas feedstream for an internal combustion engine includes storing a fuel/reductant blend in the fuel storage and delivery system, separating the reductant from the fuel/reductant blend, storing the reductant in a reductant storage tank, and injecting the reductant into the exhaust gas feedstream upstream of the aftertreatment device.

Method for supplying reductant to an aftertreatment system

A method for initiating a regeneration mode in selective catalytic reduction device utilizing hydrocarbons as a reductant includes monitoring a temperature within the aftertreatment system, monitoring a fuel dosing rate to the selective catalytic reduction device, monitoring an initial conversion efficiency, selecting a determined equation to estimate changes in a conversion efficiency of the selective catalytic reduction device based upon the monitored temperature and the monitored fuel dosing rate, estimating changes in the conversion efficiency based upon the determined equation and the initial conversion efficiency, and initiating a regeneration mode for the selective catalytic reduction device based upon the estimated changes in conversion efficiency.

Method to monitor HC-SCR catalyst NOx reduction performance for lean exhaust applications

A method for controlling hydrocarbon delivery to a hydrocarbon selective catalytic reduction device configured to receive an exhaust gas flow from an internal combustion engine includes monitoring measurable variable terms including factors affecting a conversion efficiency in the hydrocarbon selective catalytic reduction device, determining classifications of the measurable variable terms based upon measurable variable ranges, determining a desired hydrocarbon delivery value range based upon the classifications; and utilizing the desired hydrocarbon delivery value range to control the hydrocarbon delivery to the hydrocarbon selective catalytic reduction device.

Hydrocarbon selective catalytic reduction for NOx control with gasoline-fueled spark ignition engines using engine-out hydrocarbons

A method for controlling a powertrain includes selectively initiating an ammonia generation cycle, including injecting fuel into a combustion chamber of an engine before a primary combustion event to a calibrated air fuel ratio in a range lean of stoichiometry based upon generation of NOx within the combustion chamber, injecting fuel into the combustion chamber after the primary combustion event based upon an overall air fuel ratio in a range rich of stoichiometry and resulting generation of molecular hydrogen, and utilizing a catalyst device between the engine and a selective catalytic reduction device to produce ammonia.

Technique for production of ammonia on demand in a three way catalyst for a passive selective catalytic reduction system

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.

Method and apparatus for generating a reductant in an exhaust gas of a compression-ignition engine

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.

Method and apparatus for controlling ignition timing in a compression-ignition engine operating in an auto-ignition mode

There is provided a method and apparatus for exhaust gas purifying, especially NOreduction. 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&#xb0; C.

Method and apparatus for exhaust gas purifying using hydrocarbon-selective catalytic reduction

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.

Method and apparatus to control operation of a homogeneous charge compression-ignition engine

Part load operating point for a controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through negative valve overlap control operative to retain and compress combusted gases within the combustion chamber into which fuel is introduced. Combustion chamber pressures and temperatures are increased as engine load decreases. Various split-injection fuel controls are implemented during low and intermediate part load operation whereas a single-injection fuel control is implemented during high part load operation. Split-injections are characterized by lean fuel/air ratios and single-injections are characterized by either lean or stoichiometric fuel/air ratios. Controlled autoignition is thereby enabled through an extended range of engine loads while maintaining acceptable combustion stability and emissions.

Valve and fueling strategy for operating a controlled auto-ignition four-stroke internal combustion engine

A method for operating a homogeneous-charge-compression-ignition (HCCI) engine at low speed includes the steps of monitoring the operating speed and load of the HCCI engine in a stable combustion condition. When the engine cylinder load drops below a predetermined value equal to the lowest allowed load at its current engine speed, at least one cylinder is deactivated to maintain the stable combustion in the remaining activated cylinders. When the cylinder load exceeds another predetermined value at its current engine operating speed, the cylinder is reactivated.

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Oxford, MI, United States of America

Thompson M Sloane