US Patent 7188023 Misfire detection system for displacement on demand (DOD) engine

A cylinder misfire control system for a displacement on demand (DOD) engine that is operable in an activated mode and a deactivated mode includes a sensor that is responsive to rotation of a crankshaft of the engine and a first module that calculates a time derivative based on a first time period associated with a first deactivated cylinder and a second time period associated with a second deactivated cylinder. The first and second time periods are based on the rotation of the crankshaft. A second module detects a misfire occurrence in an activated cylinder based on the time period derivative.