Gm Global Technolgoy Operations, Inc.

James Donald Smith

Paul M Najt

Wei Ping Li

David J Cleary

Kushal Narayanaswamy

Kevin L Perry

Chang H Kim

Thompson M Sloane

An internal combustion engine includes a piston reciprocable within a cylinder, a phase controllable valvetrain configured to alter the effective compression ratio of the engine, and a knock sensor. A method for controlling the engine includes controlling the valvetrain to a first effective compression ratio whereat knock is detectable by the knock sensor and thereafter controlling the valvetrain to reduce the effective compression ratio to a point whereat knock is no longer detectable.

Active compression ratio modulation through intake valve phasing and knock sensor feedback

Operation of a spark ignition, direct injection engine having an aftertreatment system including an oxidation catalyst and a selective catalyst reduction device is described. The method includes controlling to a stoichiometric air/fuel ratio and retarding spark ignition timing. Engine fueling is then controlled to a lean air/fuel ratio and spark is retarded. The engine is then operated to generate ammonia reductant. Engine operation then comprises operating at a preferred air/fuel ratio and controlling spark ignition timing to a preferred timing.

Method and apparatus for controlling operation of a spark-ignition direct-injection engine

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

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Ann Arbor, MI, United States of America

James Donald Smith