A fuel injection valve is caused to inject fuel in a latter half of a compression stroke in such a manner that a fuel concentration immediately before start of combustion is higher in a middle portion of a combustion chamber than in an outer peripheral portion thereof in a low load range where the engine load is lower than a predetermined set reference load. An intake valve driving device is controlled in such a manner that an intake valve closing timing in the low load range is advanced on a retard side with respect to an intake bottom dead center in a case where the engine speed is high, as compared with a case where the engine speed is low, and intake air within a cylinder is blown back toward an intake port at least in a range where the engine speed is low.

A cylinder head for an internal combustion engine, wherein the cylinder head (1) comprises at least one first component part (12) and at least one second component part (13) joined to the at least one first component part (12), wherein the at least one first component part (12) is manufactured with the use of at least one of the group consisting of primary shaping, forming and cutting, wherein the at least one second component part (13) is manufactured with the use of an additive manufacturing method.

Some embodiments are directed to a valve assembly for use with a combustion engine. The valve assembly can include a valve stem having a plunger end, and a valve head having a stem portion disposed along a central axis and connected to the plunger end of the valve stem. The valve head can have a hollow interior portion defining interior floor and ceiling surfaces, and include ribs that extend between the interior floor and ceiling surfaces. The ribs can also extend radially around the central axis of the valve head from the stem portion to an outer circumference of the hollow interior portion. Additionally, the ribs can be configured such that a majority of an upper surface of each rib contacts the ceiling surface.

Some embodiments are directed to a valve assembly for use with a combustion engine. The valve assembly can include a valve stem having a plunger end, and a valve head having a stem portion disposed along a central axis and connected to the plunger end of the valve stem. The valve head can have a hollow interior portion defining interior floor and ceiling surfaces, and include ribs that extend between the interior floor and ceiling surfaces. The ribs can also extend radially around the central axis of the valve head from the stem portion to an outer circumference of the hollow interior portion. Additionally, the ribs can be configured such that a majority of an upper surface of each rib contacts the ceiling surface.

An internal combustion engine includes a cylinder head including an intake port, an exhaust port, a water jacket, an intake valve, an exhaust valve, an intake valve seat, and an exhaust valve seat. The water jacket is positioned between the intake port and the exhaust port. The intake valve includes an intake valve head, and the exhaust valve includes an exhaust valve head. The intake valve contacts an intake valve seat surface of the intake valve seat. The exhaust valve head contacts an exhaust valve seat surface of the exhaust valve seat. The shortest distance between the water jacket and the intake valve seat surface is shorter than the shortest distance between the water jacket and the exhaust valve seat surface.

An internal combustion engine includes a cylinder head including an intake port, an exhaust port, a water jacket, an intake valve, an exhaust valve, an intake valve seat, and an exhaust valve seat. The water jacket is positioned between the intake port and the exhaust port. The intake valve includes an intake valve head, and the exhaust valve includes an exhaust valve head. The intake valve contacts an intake valve seat surface of the intake valve seat. The exhaust valve head contacts an exhaust valve seat surface of the exhaust valve seat. The shortest distance between the water jacket and the intake valve seat surface is shorter than the shortest distance between the water jacket and the exhaust valve seat surface.

An intake valve for an engine supplies an intake gas to a combustion chamber of the engine, and an adiabatic coating layer including a polyamideimide resin and an aerogel dispersed in the polyamideimide resin and having thermal conductivity of 0.60 W/m or less may be formed on a surface portion that comes into contact with a flame during operation of the engine.

A fuel injection valve is caused to inject fuel in a latter half of a compression stroke in such a manner that a fuel concentration immediately before start of combustion is higher in a middle portion of a combustion chamber than in an outer peripheral portion thereof in a low load range where the engine load is lower than a predetermined set reference load. An intake valve driving device is controlled in such a manner that an intake valve closing timing in the low load range is advanced on a retard side with respect to an intake bottom dead center in a case where the engine speed is high, as compared with a case where the engine speed is low, and intake air within a cylinder is blown back toward an intake port at least in a range where the engine speed is low.

A system for lubricating a valve assembly of an engine. The system includes a valve bridge having a base portion is disposed on a guide rod. The guide rod is received within a hole defined in the base portion of the valve bridge to define a chamber and to receive lubricant in the chamber. The valve bridge includes an arm that is engaged with a valve stem. The valve bridge includes a passage in fluidly communicating with the chamber and an end of the arm. The system includes a valve disposed around the valve stem and valve stem guide. The valve seal includes a lip member that abuts an outer surface of the valve stem to control a flow of the lubricant from the passage to a gap defined between the valve stem and the valve stem guide.

A system for lubricating a valve assembly of an engine. The system includes a valve bridge having a base portion is disposed on a guide rod. The guide rod is received within a hole defined in the base portion of the valve bridge to define a chamber and to receive lubricant in the chamber. The valve bridge includes an arm that is engaged with a valve stem. The valve bridge includes a passage in fluidly communicating with the chamber and an end of the arm. The system includes a valve disposed around the valve stem and valve stem guide. The valve seal includes a lip member that abuts an outer surface of the valve stem to control a flow of the lubricant from the passage to a gap defined between the valve stem and the valve stem guide.