Abstract: An engine having a first and second bank of cylinders is disclosed. The engine may have improved fuel economy and emission as compared to other similar engines. In one example, engine cylinders may be deactivated.

Abstract: A system comprising an engine having a first and second bank of cylinders, said first bank having a first and second group of cylinders, said second bank having a third and fourth group of cylinders; a first emission control device coupled to said first and second group for treating gasses from said first and second group separately; a second emission control device coupled to said third and fourth group for treating gasses from said third and fourth group separately; and a controller for operating said first and third group about stoichiometry and said second and fourth group to pump air without injected fuel.

Abstract: Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.

Abstract: Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.