Patent ID: 8627659

Claim:
An engine assembly comprising: an engine structure defining a first cylinder and first and second exhaust ports in communication with the first cylinder; a first exhaust gas conduit in fluid communication with the first exhaust port, the first exhaust gas conduit and the first exhaust port defining a first exhaust gas flow path; a second exhaust gas conduit in fluid communication with the second exhaust port, the second exhaust gas conduit and the second exhaust port defining a second exhaust gas flow path; a turbine in fluid communication with the first exhaust gas flow path and including a turbine wheel rotationally driven by exhaust gas from the first cylinder provided by the first exhaust gas conduit; a first exhaust valve located within the first exhaust port and a second exhaust valve located in the second exhaust port and a piston located within the first cylinder, a flow control mechanism engaged with the second exhaust valve and maintaining the second exhaust valve in a closed position during an exhaust stroke of the piston; and a first valve lift mechanism engaged with the first exhaust valve, a second valve lift mechanism engaged with the second exhaust valve and forming the flow control mechanism, and a camshaft supported for rotation on the engine structure and defining a first cam lobe engaged with the first valve lift mechanism and a second cam lobe engaged with the second valve lift mechanism, the first valve lift mechanism and the second valve lift mechanism operable in first and second modes and located in the second exhaust gas flow path, the first mode including the first exhaust valve being displaced to an open position when the first valve lift mechanism is engaged by a peak of the first cam lobe and the second exhaust valve remaining in a closed position when the second valve lift mechanism is engaged by a peak of the second cam lobe thereby preventing the exhaust gas from the first cylinder from flowing through the second exhaust gas flow path and forcing all of the exhaust gas from the first cylinder through the first exhaust gas flow path during the first mode and wherein the second mode includes the first exhaust valve being displaced to an open position when the first valve lift mechanism is engaged by the peak of the first cam lobe and the second exhaust valve being displaced to an open position when the second valve lift mechanism is engaged by the peak of the second cam lobe thereby allowing the exhaust gas from the first cylinder to flow through both the first and second exhaust gas flow paths during the second mode.