Patent ID: 7503166

Claim:
An internal combustion engine, comprising: a gasoline fuel injection system; multiple combustion cylinders coupled with the gasoline fuel injection system and configured to receive gasoline from the gasoline fuel injection system, where the combustion cylinders are each further configured to operate selectively in one of a spark ignition mode and a compression ignition mode in which spark ignition is not employed; an electronic engine controller configured to allocate the combustion cylinders into a first group which is operated in the spark ignition mode, and a second group which is operated in the compression ignition mode, and where such allocation is dynamic such that the number of cylinders operating in each ignition mode is variable and changeable over time during operation of the internal combustion engine, and such that the internal combustion engine includes a plurality of engine operation modes at steady state, including at least an all spark mode where all cylinders are operating in the spark ignition mode, an all compression mode where all cylinders are operating in the compression ignition mode, and a mixed spark and compression mode where some of the cylinders are operating in the spark ignition mode and some of the cylinders are operating in the compression ignition mode; and a spark ignition aftertreatment system and a separate compression ignition aftertreatment system.