Abstract: An engine system includes an engine having first and second exhaust manifolds each having outlet ports and a bypass runner. A first turbocharger is in fluid communication with the outlet port of the first manifold, and a second turbocharger in fluid communication with the outlet port of the second manifold. An exhaust aftertreatment device is in fluid communication with the first and second turbochargers. A turbocharger bypass circuit includes a valve assembly having an inlet side connected in fluid communication with the bypass runners of the first and second manifolds, an outlet side in fluid communication with the aftertreatment device, and a valve having an open position in which the inlet and outlet sides are in fluid communication and a closed position in which the inlet and outlet sides are not in fluid communication.

Abstract: An engine system includes an engine having first and second exhaust manifolds each having outlet ports and a bypass runner. A first turbocharger is in fluid communication with the outlet port of the first manifold, and a second turbocharger in fluid communication with the outlet port of the second manifold. An exhaust aftertreatment device is in fluid communication with the first and second turbochargers. A turbocharger bypass circuit includes a valve assembly having an inlet side connected in fluid communication with the bypass runners of the first and second manifolds, an outlet side in fluid communication with the aftertreatment device, and a valve having an open position in which the inlet and outlet sides are in fluid communication and a closed position in which the inlet and outlet sides are not in fluid communication.

Abstract: An engine having cylinders capable of combusting gaseous fuel includes at least one spark plug per cylinder, a gaseous fuel injector extending into each cylinder and having at least one nozzle cluster containing a one or more nozzles positioned to direct gaseous fuel only toward a spark gap of an associated spark plug, and a control system operating each spark plug and each injector to deliver gaseous fuel directly to the cylinder and initiate combustion. A method for controlling an engine capable of operating with gaseous fuel includes injecting the gaseous fuel directly into each cylinder through a centrally located injector having a plurality of clusters of nozzles, each cluster associated with one of at least two spark plugs positioned closer to a cylinder wall than to the injector, each cluster directing the gaseous fuel toward an associated spark plug gap.

Abstract: A system and method for controlling a pressure responsive device in an engine is provided. The device can vary a compression ratio in an engine cylinder. The method includes supplying fluid pressure to the pressure responsive device to change a compression ratio in the cylinder. The method further includes indicating when the device has deteriorated response. Finally, the method includes increasing the fluid pressure to the device to change the compression ratio in the cylinder in response to the indication.

Abstract: A system and method for controlling an engine is provided. The engine includes first and second pressure responsive devices varying compression ratios in first and second engine cylinders, respectively. The method includes commanding the first and second devices to decrease compression ratios in the first and second cylinders, respectively. The method further includes indicating when the first device has not decreased a compression ratio in the first cylinder. Finally, the method includes commanding the second device to increase a compression ratio in the second cylinder to reduce engine torque fluctuations.

Abstract: A strategy and control system for a variable displacement engine in which cylinder deactivation is obtained by intake cam phasing and exhaust valve deactivation. Fuel control for the engine and spark deactivation are sequenced with valve deactivation to avoid transferring engine exhaust gases to the intake manifold of the engine during a transition between full cylinder operation and partial cylinder operation. Excess air flow through the exhaust system for the engine is avoided during a transition from partial cylinder operation to full cylinder operation. These features achieve stable engine performance during the transition.

Abstract: A system and method for controlling an engine is provided. The engine includes first and second pressure responsive devices varying compression ratios in first and second engine cylinders, respectively. The method includes commanding the first and second devices to decrease compression ratios in the first and second cylinders, respectively. The method further includes indicating when the first device has not decreased a compression ratio in the first cylinder. Finally, the method includes commanding the second device to increase a compression ratio in the second cylinder to reduce engine torque fluctuations.

Abstract: A system and method for controlling a pressure responsive device in an engine is provided. The device can vary a compression ratio in an engine cylinder. The method includes supplying fluid pressure to the pressure responsive device to change a compression ratio in the cylinder. The method further includes indicating when the device has deteriorated response. Finally, the method includes increasing the fluid pressure to the device to change the compression ratio in the cylinder in response to the indication.

Abstract: A strategy and control system for a variable displacement engine in which cylinder deactivation is obtained by intake cam phasing and exhaust valve deactivation. Fuel control for the engine and spark deactivation are sequenced with valve deactivation to avoid transferring engine exhaust gases to the intake manifold of the engine during a transition between full cylinder operation and partial cylinder operation. Excess air flow through the exhaust system for the engine is avoided during a transition from partial cylinder operation to full cylinder operation. These features achieve stable engine performance during the transition.

Abstract: A variable displacement internal combustion engine having an intake manifold for providing ambient air and a boost manifold is provided. Either designated cylinders or selected cylinders may be operated in a non-firing mode wherein air may be compressed in a non-firing cylinder and ported to the boost manifold to provide boosted air pressure to firing cylinders. Each cylinder has an intake valve, an intake/compressed air valve, and an exhaust valve. The intake valves are controlled by electromagnetic actuators. The exhaust valve may be controlled by an electromagnetic valve actuator or a conventional valve actuator, if desired. Intake/compressed air valves of cylinders operating in the non-firing, compressor mode are ported to the boost manifold and selectively timed to provide compressed air to the boosted manifold when additional torque is desired provided that some of the cylinders are operating in the compressor mode.