A moment-cancelling, four-stroke engine is disclosed. The engine includes a first cylinder having a first piston and a second cylinder having a second piston, a first crankshaft operably connected to the first piston and a second crankshaft operably connected to the second piston. The first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction that is opposite the first direction to cancel the moments applied to the engine and reduce engine vibration.

Systems and methods for operating an engine that includes cylinders that may be deactivated are presented. In one example, intake and exhaust valves of a cylinder may be operated according to valve operation for a conventional four stroke cycle. The same valves may be operated differently during a four stroke cycle to provide air charge and exhaust charge to active cylinders during a different four stroke cycle.

A moment-cancelling, four-stroke engine is disclosed. The engine includes a first cylinder having a first piston and a second cylinder having a second piston, a first crankshaft operably connected to the first piston and a second crankshaft operably connected to the second piston. The first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction that is opposite the first direction to cancel the moments applied to the engine and reduce engine vibration.

Systems and methods for operating an engine that includes cylinders that may be deactivated are presented. In one example, intake and exhaust valves of a cylinder may be operated according to valve operation for a conventional four stroke cycle. The same valves may be operated differently during a four stroke cycle to provide air charge and exhaust charge to active cylinders during a different four stroke cycle.