Provided is an engine with a starter valve arranged in a compact space and with a cylinder head having a cooling water passage and a starter valve feeding compressed air to a combustion chamber. The starter valve is arranged parallel in the axial direction to a cylinder while fitted into a sleeve, and a portion of the cooling water passage is formed by the outer surface of the sleeve fitted into a starter valve insertion hole formed in the cylinder head. A starting air passage orthogonal to the axial direction of the starter valve insertion hole is formed in the cylinder head, and a portion of the wall surface of the starting air passage is formed by the end surface on one side of the sleeve.

A single-cylinder internal combustion engine includes a knock sensor mounted thereto to suppress a temperature increase of the knock sensor and at the same time detect knocking with high accuracy. The engine includes a cylinder block having a cylinder provided therein, and a cylinder head connected to the cylinder block. On a surface of the cylinder block and the cylinder head, one or more fins protruding from the surface are provided. On the surface of the cylinder block, a sensor mounting boss protruding from the surface and being continuous with a portion of the one or more fins is provided. A knock sensor arranged to detect knocking is mounted to the sensor mounting boss.

A single-cylinder internal combustion engine includes a knock sensor mounted thereto to suppress a temperature increase of the knock sensor and at the same time detect knocking with high accuracy. The engine includes a cylinder block having a cylinder provided therein, and a cylinder head connected to the cylinder block. On a surface of the cylinder block and the cylinder head, one or more fins protruding from the surface are provided. On the surface of the cylinder block, a sensor mounting boss protruding from the surface and being continuous with a portion of the one or more fins is provided. A knock sensor arranged to detect knocking is mounted to the sensor mounting boss.

A cylinder head includes an exhaust port through which exhaust gas discharged out of a combustion chamber of an internal combustion engine passes. The cylinder head includes a first fin and a second fin projecting from an inner wall of the exhaust port and extending in a flow direction of the exhaust gas. The cylinder head includes a first projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the first fin. The cylinder head also includes a second projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the second fin.

A cylinder head includes an exhaust port through which exhaust gas discharged out of a combustion chamber of an internal combustion engine passes. The cylinder head includes a first fin and a second fin projecting from an inner wall of the exhaust port and extending in a flow direction of the exhaust gas. The cylinder head includes a first projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the first fin. The cylinder head also includes a second projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the second fin.

An exhaust port liner, which may include a superalloy and may be manufactured by an additive manufacturing process, includes a monolithic structure including an outlet disposed an angle relative to an inlet, and a sidewall defining a cavity to provide enhanced thermal performance in reciprocating internal combustion engines. A cylinder head of an internal combustion engine may include a cylinder head frame, and the exhaust port liner may be disposed proximate the frame inner mounting surface, with an outer surface of the exhaust port liner conforming to an inner mounting surface of the cylinder head frame.

An exhaust port liner, which may include a superalloy and may be manufactured by an additive manufacturing process, includes a monolithic structure including an outlet disposed an angle relative to an inlet, and a sidewall defining a cavity to provide enhanced thermal performance in reciprocating internal combustion engines. A cylinder head of an internal combustion engine may include a cylinder head frame, and the exhaust port liner may be disposed proximate the frame inner mounting surface, with an outer surface of the exhaust port liner conforming to an inner mounting surface of the cylinder head frame.

A cylinder head includes an exhaust port through which exhaust gas discharged out of a combustion chamber of an internal combustion engine passes. The cylinder head includes a first fin and a second fin projecting from an inner wall of the exhaust port and extending in a flow direction of the exhaust gas. The cylinder head includes a first projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the first fin. The cylinder head also includes a second projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the second fin.

A cylinder head includes an exhaust port through which exhaust gas discharged out of a combustion chamber of an internal combustion engine passes. The cylinder head includes a first fin and a second fin projecting from an inner wall of the exhaust port and extending in a flow direction of the exhaust gas. The cylinder head includes a first projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the first fin. The cylinder head also includes a second projection projecting from the inner wall of the exhaust port and extending in a direction intersecting the second fin.

An exhaust port liner, which may include a superalloy and may be manufactured by an additive manufacturing process, includes a monolithic structure including an outlet disposed an angle relative to an inlet, and a sidewall defining a cavity to provide enhanced thermal performance in reciprocating internal combustion engines. A cylinder head of an internal combustion engine may include a cylinder head frame, and the exhaust port liner may be disposed proximate the frame inner mounting surface, with an outer surface of the exhaust port liner conforming to an inner mounting surface of the cylinder head frame.