Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, a position of an engine air intake throttle is adjusted during cylinder deactivation to control intake manifold pressure for cylinder reactivation. Closing of the throttle may be timed based on an actual total number of cylinder induction events expected to provide a desired engine intake manifold pressure.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, valves of a cylinder are deactivated in a closed state in response to an indication of degradation of a valve of the cylinder. Further, fuel flow to the cylinder may be stopped via ceasing to inject fuel to the cylinder.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, valves of a cylinder are deactivated in a closed state in response to an indication of degradation of a valve of the cylinder. Further, fuel flow to the cylinder may be stopped via ceasing to inject fuel to the cylinder.

Systems and methods for detecting and controlling knock in an engine are presented. In one example, engine knock sensors are selected based on whether or not certain cylinders are activated and combusting air and fuel or deactivated and not combusting air and fuel. Output of selected knock sensors is the basis for adjusting engine spark timing.

Systems and methods for detecting and controlling knock in an engine are presented. In one example, engine knock sensors are selected based on whether or not certain cylinders are activated and combusting air and fuel or deactivated and not combusting air and fuel. Output of selected knock sensors is the basis for adjusting engine spark timing.

Systems and methods for operating an engine with deactivating and non-deactivating valves is presented. In one example, the engine may include non-deactivating intake valves, deactivating intake valves, and only non-deactivating exhaust valves. The non-deactivating exhaust valves may operate to open and close during an engine cycle while deactivating intake valves remain closed during the engine cycle to prevent air flow through selected engine cylinders.

Systems and methods for operating an engine with deactivating and non-deactivating valves is presented. In one example, the engine may include non-deactivating intake valves, deactivating intake valves, and only non-deactivating exhaust valves. The non-deactivating exhaust valves may operate to open and close during an engine cycle while deactivating intake valves remain closed during the engine cycle to prevent air flow through selected engine cylinders.

The invention relates to a control device for a multi-cylinder engine provided with an oil pump, a hydraulically operated valve characteristic control device which changes valve characteristics of at least one of an intake valve and an exhaust valve; and a hydraulically operated valve stop device which stops at least one of the intake valve and the exhaust valve when a reduced cylinder operation is performed. The control device for a multi-cylinder engine is provided with a valve control unit which operates the valve stop device after an operation of the valve characteristic control device is completed when the valve characteristic control device is operated at a time of request for the reduced cylinder operation.

The invention relates to a control device for a multi-cylinder engine provided with an oil pump, a hydraulically operated valve characteristic control device which changes valve characteristics of at least one of an intake valve and an exhaust valve; and a hydraulically operated valve stop device which stops at least one of the intake valve and the exhaust valve when a reduced cylinder operation is performed. The control device for a multi-cylinder engine is provided with a valve control unit which operates the valve stop device after an operation of the valve characteristic control device is completed when the valve characteristic control device is operated at a time of request for the reduced cylinder operation.

Methods and systems are provided for improving the performance of a variable displacement engine. Split injection and spark retard may be used in active cylinder during a VDE mode to heat an exhaust catalyst and extend the duration of VDE mode operation. Split injection and spark retard may also be used in reactivated cylinders at a time of cylinder reactivation to improve restart combustion stability.