Methods and systems are provided for a cooling arrangement. In one example, a plurality of engine oil passages extend through a cylinder head coolant jacket. The plurality of engine oil passages is fluidly separated from the cylinder head coolant jacket.

A cylinder head arrangement for an internal combustion engine is provided. The cylinder head includes an integrated exhaust manifold having first and second exhaust passages to collect exhaust gas from respective cylinders to direct the exhaust gas to respective outlets of the cylinder head. The cylinder head includes a flange where the first and second outlets exit the cylinder head for connection with a turbocharger.

The disclosure provides a multi-cylinder internal combustion engine having a cylinder head that includes an exhaust port capable of cooling exhaust gas more effectively. The cylinder head includes: a first ceiling surface that closes a first cylinder having a cylinder axis separated from an exhaust opening by a first distance; a second ceiling surface that closes a second cylinder having a cylinder axis separated from the exhaust opening by a second distance shorter than the first distance; and an exhaust port that extends toward the exhaust opening from two port openings which are open to a combustion chamber for each individual cylinder. The exhaust port individually extends from each of the port openings and merges with each cylinder outside a joining surface of the cylinder head for a cylinder block in a plan view.

A four stroke internal combustion engine is disclosed comprising at least one cylinder arrangement, an exhaust conduit, and at least one turbine. The cylinder arrangement comprises an exhaust port arrangement configured to open and close an exhaust flow area, A.sub.CYL. The cylinder arrangement has a maximum volume, V.sub.MAX. The exhaust conduit extends between the exhaust flow area, A.sub.CYL, and a turbine wheel inlet area, A.sub.TIN, of the turbine and has an exhaust conduit volume, V.sub.EXH that is ≤0.5 times the maximum volume, V.sub.MAX. The exhaust port arrangement is configured to expose the exhaust flow area, A.sub.CYL, at a size of at least 0.22 times the maximum volume, V.sub.MAX, when a piston of the cylinder arrangement is at the bottom dead centre, BDC.

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.

Methods and systems are provided for a cooling arrangement. In one example, a plurality of engine oil passages extend through a cylinder head coolant jacket. The plurality of engine oil passages is fluidly separated from the cylinder head coolant jacket.

In a spark-ignition internal combustion engine in which a protrusion including an intake-side inclined surface and an exhaust-side inclined surface is formed on a top surface of a piston, and a cavity is formed in the protrusion at a position associated with a spark plug, the intake-side inclined surface and the exhaust-side inclined surface are formed in such a way that a ratio of a length of the exhaust-side inclined surface with respect to a length of the intake-side inclined surface is 1.25 or larger in a cross section passing through a center axis of the piston and orthogonal to an axis direction of a crankshaft.

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.

A cylinder head with integrated exhaust manifold includes a cylinder head housing, an exhaust manifold, and first, second and third water jackets. The cylinder head housing has a combustion chamber formed in a bottom surface thereof and an internal receiving space. The exhaust manifold is received in the space of the cylinder head housing and is connected to exhaust ports of the cylinder head housing. The first water jacket is received in the space of the cylinder head housing and disposed adjacent to the combustion chamber. The second water jacket is received in the space of the cylinder head housing and disposed to contact a bottom of the exhaust manifold. The third water jacket is received in the space of the cylinder head housing and disposed to contact a top of the exhaust manifold.

A two-stroke internal combustion engine has an engine block having a cylinder block and a cylinder head. The cylinder block defines a cylinder, an exhaust passage, and an exhaust valve passage. The engine also has a piston, an exhaust valve actuator operatively connected to at least one of the cylinder block and the cylinder head, and a reciprocating exhaust valve disposed at least in part in the exhaust valve passage. The exhaust valve has a shaft operatively connected to a valve actuator, and a blade connected to the shaft. A channel is defined along a face of the blade. The channel and a wall of the exhaust valve passage together define at least in part a valve passage. The valve passage permits flow of exhaust gas along the face of the blade. A width of the valve passage is at least a third of a width of the blade.