Methods and systems are provided for a 2-port integrated exhaust manifold for an inline-3, inline-6, V-6, and/or V-12 engine. In one example, a system may include an exhaust manifold integrated within a cylinder head of an engine block. The integrated exhaust manifold may include a first set of two runners from a first outer cylinder coupled to a first manifold exhaust port, a second set of two runners of a second outer cylinder coupled to a second manifold exhaust port, and one runner of an inner cylinder coupled to the first manifold exhaust port and another runner of the inner cylinder coupled to the second manifold exhaust port.

Methods and systems are provided for thermally insulating an integrated exhaust manifold for a cylinder head of an applied-ignition, liquid-cooled internal combustion engine. In one example, a method may include regional insulation at a collection point where individual exhaust lines and/or partial exhaust lines merge to form an overall exhaust line within the cylinder head. The regional insulation may be formed integrally with a seal and coupled to an outlet flange of the cylinder head and may include a series of tongue-like projections that extend from the cylinder head outlet flange toward the cylinder exhaust lines.

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 internal combustion engine includes: a cylinder block including multiple cylinders; a cylinder head; and a turbocharger including an inlet port connected to an exhaust outlet of the cylinder head. The inlet port includes a first wall portion located between one cylinder out of the two outermost cylinders and the central axis of the inlet port in the cylinder array direction, and a second wall portion located on the opposite side of the central axis of the inlet port from the first wall portion. The first wall portion includes a thick-walled portion that is greater in thickness than the second wall portion, and a thin-walled portion that is smaller in thickness than the thick-walled portion and is located upstream of the thick-walled portion in the direction of exhaust gas flow.

Marine engine includes a cylinder block having first and second banks of cylinders that are disposed along a longitudinal axis and extend transversely with respect to each other in a V-shape so as to define a valley therebetween. A catalyst receptacle is disposed at least partially in the valley and contains at least one catalyst that treats exhaust gas from the marine engine. A conduit conveys the exhaust gas from the marine engine to the catalyst receptacle. The conduit receives the exhaust gas from the first and second banks of cylinders and conveys the exhaust gas to the catalyst receptacle. The conduit reverses direction only once with respect to the longitudinal axis.

Systems and methods for operating a turbocharged engine are described. In one example, a turbocharger system, comprising: a bearing housing including a turbine and at least one compressor coupled to the turbine via a shaft; and wherein the turbine comprises a stator stage and a rotor stage mounted to the cylinder head by the bearing housing and positioned in an exhaust passage of a cylinder head. In this way, a more compact design is achieved which eliminates the cost and complexity of a turbine housing and improves turbine efficiency by positioning the turbine closer to the exhaust pulses.

A cooling structure for a cylinder head, wherein the cylinder head has formed therein an exhaust manifold having branch sections and also having a collecting section to which the branch sections connect; a first water jacket and a second water jacket, which cover the exhaust manifold; connection passages which supply cooling water in the second water jacket to the first water jacket; and a cooling water outlet which connects the first water jacket to the outside. The connection passages include the first connection passage which is closest to the collecting section, and the second connection passage which is located at the downstream end of each of the water jackets. The flow passage cross-sectional area of the second connection passage is set to be less than the flow passage cross-sectional area of the first connection passage.

An internal combustion engine has a cooling jacket at least partially integrated in the cylinder head. The engine has two groups of cylinders: inside cylinders and outside cylinders. Each cylinder has at least one exhaust port, each leading to an individual duct. Individual ducts of outside cylinders converge to form an outside combined duct. In a four-cylinder engine or cylinder head, individual ducts of inside cylinders converge to form an inside combined duct with the inside combined duct remaining separated from the outside combined duct by the cooling jacket. The inside combined duct is farther away from the mounting surface of the cylinder head to the cylinder block than the outside combined duct. The cooling jacket includes upper, middle, and lower cooling jackets and connectors between the upper and lower cooling jackets.