Gm Global Technolgoy Operations, Inc.

Ryu Hariyoshi

Shouxian Ren

Ping Ge

A method is provided for generating rapid light-off for a diesel oxidation catalyst (DOC) close-coupled to a compression-ignition engine. The engine includes an intake passage in fluid communication with a combustion chamber, a throttle for controlling a flow of intake air through the intake passage, and an exhaust passage configured to channel an exhaust gas from the combustion chamber to the DOC. The method includes starting the engine to commence a warm-up thereof and regulating the throttle to restrict supply of the intake airflow to the combustion chamber. The method additionally includes injecting a predetermined amount of fuel into the combustion chamber during the engine's exhaust cycle such that the injected fuel is carried by the exhaust gas and burned in the exhaust passage. Regulating the throttle and injecting fuel during the warm-up of the engine together increase temperature of the exhaust gas for rapid light-off of the close-coupled DOC.

Increased exhaust temperature warm-up for a rapid light-off of a close-coupled diesel oxidation catalyst

An exhaust system includes a selective catalytic reduction (SCR) unit and a NOabsorber that may include a lean NOtrap (LNT). The NOabsorber absorbs NOand releases the NOabsorbed in the NOabsorber into the SCR unit. The SCR unit converts NOof exhaust gas into nitrogen and water.

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Auburn Hills, MI, United States of America

Ryu Hariyoshi