An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

A cylinder head assembly includes a cast cylinder head and a turbocharger housing integrally cast with the cylinder head. The integrated cylinder head and turbocharger housing includes: (i) a compact low wetted area to provide an uninterrupted flow path pointed directly at a catalyst face to facilitate achieving cold start emissions targets, (ii) a casting core assembly with specific core geometry and steps for assembly to enable core assembly while meeting all cylinder head and integrated turbine housing functional requirements, (iii) an oxygen sensor disposed pre-turbine in an integrated exhaust manifold, and (iv) a fully integrated PCV make-up air system.

An engine is provided, which includes an engine body including a plurality of cylinders, each of the cylinders being provided with an intake port, an exhaust port, an intake valve, and an exhaust valve, an intake passage and an exhaust passage connected to the engine body, and a turbocharger including a turbine provided to the exhaust passage and a compressor provided to the intake passage. A geometric compression ratio of the cylinder is 11:1 or higher. An open period of the intake valve is a range of 270° or larger by a crank angle. The exhaust passage includes a plurality of independent exhaust passages, each communicating with the exhaust port of one cylinder or with the exhaust ports of two or more cylinders of which timings of exhaust strokes are discontinuous from each other, and connecting the engine body to the turbine.

A method of forming a thermally isolated exhaust port, the method comprising placing a chill device around an exhaust port core in a mold for an engine cylinder head, forming the engine cylinder head with an exhaust port using a casting process, generating, in the cylinder head with the exhaust port during the casting process, nodular graphite iron proximate the chill device around the exhaust port core, and forming the thermally isolated exhaust port containing nodular graphite iron in the cylinder head.

A shut-off member for a turbocharger for an internal combustion engine includes a first channel, a second channel, and a wall that separates the first channel from the second channel. A shut-off member opening is formed in the wall that connects the first channel and the second channel. The shut-off member opening is selectively openable and closable by a shut-off member body. A cooling channel is disposed in the wall and at least partially surrounds the shut-off member opening.

A method of forming a thermally isolated exhaust port, the method comprising applying an endothermic material to an exhaust port core in a mold for an engine cylinder head, forming the engine cylinder head with an exhaust port using a casting process, generating, in the cylinder head with the exhaust port during the casting process, nodular graphite iron proximate the endothermic material around the exhaust port core, and forming the thermally isolated exhaust port containing nodular graphite iron in the cylinder head.

A first coolant flow passage is provided to extend in a longitudinal direction of a cylinder head. In at least one of cross sections perpendicular to the longitudinal direction, the first coolant flow passage is located between a flat plane including central axes of a plurality of combustion chambers and parallel to the longitudinal direction and a central line plane including central lines of a plurality of intake ports. In at least one of cross sections perpendicular to the longitudinal direction, at least a portion of a second coolant flow passage is located between the combustion chamber and the first coolant flow passage. A coolant at a temperature lower than that of a coolant flowing in the second coolant flow passage flows in the first coolant flow passage.

A shut-off member for a turbocharger for an internal combustion engine includes a first channel, a second channel, and a wall that separates the first channel from the second channel. A shut-off member opening is formed in the wall that connects the first channel and the second channel. The shut-off member opening is selectively openable and closable by a shut-off member body. A cooling channel is disposed in the wall and at least partially surrounds the shut-off member opening.

In inline four cylinder internal combustion engine (1), exhaust ports for a #2 cylinder and a #3 cylinder merge inside cylinder head (3) and form an opening serving as a single collective exhaust port. Exhaust manifold (5) has individual exhaust pipes (6, 7) for #1 and #4 cylinders and collective exhaust pipe (8), and the leading ends of these three exhaust pipes (6, 7, 8) are connected to catalytic converter (11). Exhaust gas introduction angle (θ2) of each of individual exhaust pipes (6, 7) is larger by 30-60 degrees than exhaust gas introduction angle (θ1) of collective exhaust pipe (8). Consequently, flow velocity distribution and temperature distribution in a catalyst carrier become uniform.

Systems are provided for an integrated exhaust manifold that may be used in a variety of engine systems. In one example, an integrated exhaust manifold may include a central axis running from an inlet end to an outlet end of the integrated exhaust manifold and two exhaust outlets arranged at the outlet end and coupled to a common collecting line, the two exhaust outlets symmetrically positioned across the central axis and having a same diameter, where each exhaust outlet of the two exhaust outlets has a passage axis arranged parallel to the central axis. A first exhaust outlet of the two exhaust outlets may be permanently blocked and a second exhaust outlet of the two exhaust outlets may be coupled to an exhaust system of an engine system.