Patent ID: 6928988

Claim:
An engine comprising an engine body having multiple cylinders, an engine management system at least controlling enablement of the cylinders, the engine management system including a controller configured to group the cylinders into at least a first group of cylinders and a second group of cylinders and to operate the first group of cylinders while disabling the second group of cylinders, the controller further configured to subsequently disable the first group of cylinders and operate the second group of cylinders, and an exhaust system having a plurality of exhaust passages, each exhaust passage communicating with one of the cylinders, the exhaust passages communicating with the first group of cylinders merging together, and the exhaust passages communicating with the second group of cylinders merging together, and at least one catalyst being disposed downstream of where the corresponding exhaust passages merge together, wherein the first group of cylinders comprises cylinders disposed in both banks of cylinders, and the second group of cylinders comprises cylinders disposed in both banks of cylinders.