An internal combustion engine has a cylinder head having an integrated exhaust manifold which has multiple exhaust ducts; and a secondary air system for supplying ambient air that is additionally supplied through an inlet as secondary air into the exhaust manifold into the exhaust gas flow downstream from the exhaust valves of the internal combustion engine during the cold-start phase. For fresh air supply, the secondary air system has a plurality of supply ducts that connect a distributor block of the secondary air system to an exhaust duct and are arranged in the integrated exhaust manifold and each provided with a valve assembly. Each valve assembly has a blocking means in the form of a closure flap that is pivotable about a pivot axis at a distance from the center of mass of the blocking means. According to the installation position of the internal combustion engine in a motor vehicle, and owing to this eccentric arrangement of the pivot axis, the blocking means assumes a defined closed position under the influence of gravity when there is no pressure difference between the exhaust manifold and the secondary air system and opens automatically under the influence of a relative overpressure in the gas pressure on the side of the secondary air system in relation to the gas pressure on the side of the exhaust manifold.

Exhaust systems are described. In examples, an exhaust flow path couples exhaust ports with one or more turbochargers of an engine. The exhaust flow path may have a portion flowing through a cylinder head (e.g., couplable to the exhaust ports) and a portion flowing through an exhaust manifold (couplable to the cylinder head and the turbocharger(s)). The flow paths may be shaped to reduce the sharpness of turns between the exhaust ports and the turbocharger(s). For example, curves along the flow path may be less than 90 degrees or have a minimum curve radius, which may vary along the flow path. Additionally, at least two, independent flow paths may exist between the exhaust ports and the turbocharger(s). The cross-sectional shape of any part of the flow path may be elliptical, including at inlets and outlets.

An engine system includes a cylinder block, and a cylinder head attached to the cylinder block and including exhaust ports. Exhaust collection passages are formed in the cylinder head and each fluidly connect to one of the exhaust ports. An unburned hydrocarbon (UHC) emissions mitigation conduit fluidly connects to the exhaust ports to route UHC to an oxidation catalyst or for recirculation.

Exhaust systems are described. In examples, an exhaust flow path couples exhaust ports with one or more turbochargers of an engine. The exhaust flow path may have a portion flowing through a cylinder head (e.g., couplable to the exhaust ports) and a portion flowing through an exhaust manifold (couplable to the cylinder head and the turbocharger(s)). The flow paths may be shaped to reduce the sharpness of turns between the exhaust ports and the turbocharger(s). For example, curves along the flow path may be less than 90 degrees or have a minimum curve radius, which may vary along the flow path. Additionally, at least two, independent flow paths may exist between the exhaust ports and the turbocharger(s). The cross-sectional shape of any part of the flow path may be elliptical, including at inlets and outlets.

Methods, assemblies and apparatuses are for forming a cooling jacket in a cast part of a marine engine, for example in a cylinder head for the marine engine. A cooling jacket core comprises a longitudinally elongated first portion that forms a first flow path for conveying cooling fluid through the cast part in a first direction and a longitudinally elongated second portion that forms an opposite, second flow path for conveying cooling fluid through the cast part in an opposite, second direction. At least one bridge integrally supports the first and second portions with respect to each other during casting. At least one plug is configured to fit in the cast part where the bridge was located so as to separate the first and second flow paths from each other while sealing the first and second flow paths from an opposite side of the cast part.

An assembly for controlling a flow of exhaust gas from an engine includes a blowdown manifold and a scavenge manifold adapted to be coupled to the engine for receiving the exhaust gas. The assembly also includes a valve system including a blowdown pipe coupled to the blowdown manifold, a scavenge pipe coupled to the scavenge manifold, a scavenge valve member coupled to the scavenge pipe and disposed within the scavenge passage, and at least one actuator operably coupled to the scavenge valve member. The assembly further includes a turbocharger coupled to the blowdown pipe, with the turbocharger including a turbine housing defining a turbine housing interior. The scavenge valve member of the valve system is disposed outside of the turbine housing interior.

The application relates to internal combustion engines, cylinder heads, exhaust passages, and shapes and configurations of the exhaust passages. The exhaust passage may have cross-sectional shapes formed by two limbs. The cross-sectional shape of the exhaust passage may change as the passage extends. The exhaust passage may also merge with other exhaust passage. The exhaust passage may be part of a cylinder head or an exhaust manifold.

A multi-cylinder engine includes an engine body having first and second cylinder groups, first and second exhaust passage groups each having a plurality of independent exhaust passage parts and a collective exhaust passage part, and an exhaust gas recirculation (EGR) passage. In a plan view in cylinder axis directions, the passage groups are disposed adjacent to each other, and, in the first exhaust passage group, a first independent exhaust part of the plurality of independent exhaust passage parts is connected to the EGR passage and a second independent exhaust passage part is connected to the collective exhaust passage part so as to be directed to a connection of the first independent exhaust passage part to the collective exhaust passage part, and in the second exhaust passage group, an opening of the collective exhaust passage part is offset toward the first exhaust passage group in a lineup direction.

An internal combustion engine having an exhaust log structure onto which a plurality of turbochargers is connected, each turbocharger having a turbine connected to the exhaust log structure and having an inlet fluidly connectable to a respective one of the plurality of outlet ports, an exhaust valve disposed at a turbine outlet such that the flow of exhaust gas out of the turbine is fluidly blocked, and an actuator associated with the exhaust valve and operating to move the exhaust valve from a closed position to an open position and vice versa. An electronic controller provides a command to the actuator to move the exhaust valve between the open and closed positions and is programmed to selectively open two one or more exhaust valves based on an operating condition of the engine.

A multi-cylinder engine having an engine body with a cylinder head is provided. The engine includes first and second cylinder groups, each having a plurality of independent exhaust passage parts provided to the cylinder head and connected to cylinders of the first and second cylinder groups, respectively, and first and second collective exhaust passage parts collecting the first and second pluralities of independent exhaust passage parts at a location downstream in an exhaust gas flow direction, and having an opening formed in the side surface part of the cylinder head, first and second exhaust-pipe parts each connected to the openings of the first and second collective exhaust passage parts, respectively, an exhaust gas recirculation (EGR) passage connected at one end to the first exhaust passage group and connected at the other end to an intake passage, and an exhaust gas temperature sensor provided to the first exhaust-pipe part.