Methods and systems are provided for implementing fluid injection through a cylinder valve seat. The engine system may include a cylinder valve with a valve head mating with a valve seat when the valve is closed. The valve seat includes an injection orifice blocked by the valve head when the cylinder valve is closed and unblocked when the cylinder valve is opened.

An engine with a reduced cooling loss, may include a cylinder block, a piston and a cylinder head, wherein the engine displacement chamber is 300cc-700cc and an entire combustion chamber volume including a first volume of the cylinder block and a second volume of the cylinder head is defined between an inner surface of the cylinder head, a distal end of an intake valve mounted in the cylinder head when the intake valve is closed, and an upper surface of the piston positioned at a top-dead center of the engine in the cylinder block, wherein a compression ratio between an engine displacement chamber and the entire combustion chamber is 10.0 or more:1, and wherein the second volume of the cylinder head is 40%-70% of the entire combustion chamber volume.

An internal combustion engine includes: intake and exhaust ports; an intake valve including an intake valve shaft and an intake valve head; and an exhaust valve including an exhaust valve shaft and an exhaust valve head. The surface of the intake valve includes an intake-valve-head front surface exposed in a combustion chamber when the intake valve is closed and an intake-valve-head back surface exposed in the intake port when the intake valve is closed. The surface of the exhaust valve includes an exhaust-valve-head front surface exposed in the combustion chamber when the exhaust valve is closed and an exhaust-valve-head back surface exposed in the exhaust port when the exhaust valve is closed. The arithmetic mean roughness of the whole exhaust-valve-head back surface is greater than the arithmetic mean roughness of each of the whole intake-valve-head front surface, the whole intake-valve-head back surface and the whole exhaust-valve-head front surface.

Methods and systems are provided for implementing fluid injection through a cylinder valve seat. The engine system may include a cylinder valve with a valve head mating with a valve seat when the valve is closed. The valve seat includes an injection orifice blocked by the valve head when the cylinder valve is closed and unblocked when the cylinder valve is opened.

A head assembly for an internal combustion engine includes an electromagnetic valve actuation system. The head has an intake or exhaust passage defined therein. A valve is disposed in the passage and is operable to selectively open and close the passage. The head has a cooling passage defined therein for passage of a cooling fluid. An electromagnetic actuator has a piston in mechanical communication with the valve and a coil in fluid communication with the cooling passage. The electromagnetic actuator is operable to move the valve between a closed and an open position.

An engine includes: a cylinder head; a cam housing fastened to the cylinder head; a camshaft rotatably supported by the cam housing and supplied with lubricating oil; and a head cover fastened to the cam housing, wherein the cam housing includes a side wall extending along the camshaft, and an inner side surface of the side wall includes a recessed region recessed downward in a gravity direction.

The invention relates to a cylinder head (1) for an internal combustion engine having at least one cylinder, having at least one valve seat ring (3) for a lifting valve, wherein the valve seat ring (3) is surrounded by an annular cooling channel (4) for a coolant which is formed at least partially into the cylinder head (1), wherein the cooling channel (4) surrounds the valve seat ring at least partially and extends between at least one inlet (5, 15, 25) and at least one outlet (6). In order to reduce the valve wear, it is provided that, as viewed in a section perpendicularly with respect to the axis (3a) of the valve seat ring (3), the cooling channel (4) has at least one preferably substantially crescent-shaped bulge (10) in the region of the inlet (5, 55, 25) and/or the outlet (6).

An engine with a reduced cooling loss, may include a cylinder block and a cylinder head, wherein an entire combustion chamber volume of the cylinder block and the cylinder head is 300 cc-700 cc, a compression ratio is 10.0 or more, and the volume of the cylinder head is 40%-70% of the entire combustion chamber volume.

The invention relates to a cooled inlet or outlet valve (4) for internal combustion engines, comprising a valve disc (6), a valve stem (8), and a hollow space (10) inside the valve stem (8) and the valve disc (6). A coolant (12) is arranged in the hollow space (10). The valve is designed comprising at least two parts and has on a valve disc surface (22) an opening (18) which is closed by a cover (20), wherein the cover (20) is additionally provided with at least one relief groove (34) which relieves a joint (32) between the opening (18) in the valve disc surface (22) and the cover (20).

A hydraulic supply device for a valve stopping mechanism includes: a specific hydraulic oil supply passage which constantly supplies hydraulic oil, a valve stopping mechanism incorporated in a cylinder head, and configured to stop at least one of an intake valve and an exhaust valve, a valve stopping oil passage which supplies hydraulic oil to the valve stopping mechanism, a control valve which controls the supply of hydraulic oil to the valve stopping oil passage, and a communication oil passage which communicates between the valve stopping oil passage and the specific hydraulic oil supply passage, and provided with a restrictor therebetween. The specific hydraulic oil supply passage is connected to an oil supply portion for a portion to be lubricated or for a portion to be cooled in the engine at a position downstream of a connection position with respect to the communication oil passage in an oil supply direction.