An engine intake system includes: a port partition disposed to divide an intake port of a cylinder head into an upper portion and a lower portion; a first intake manifold configured to supply air, which flows from an air cleaner through a charger and an intercooler, to one of the upper portion and the lower portion of the port partition; a second intake manifold configured to supply the air, which flows from the air cleaner while bypassing the charger and the intercooler, to the other of the upper portion and the lower portion of the port partition; and a bypass valve disposed and configured to pass and block the air flowing into the second intake manifold from the air cleaner.

A method of forming a thermally isolated exhaust port, the method comprising placing a chill device around an exhaust port core in a mold for an engine cylinder head, forming the engine cylinder head with an exhaust port using a casting process, generating, in the cylinder head with the exhaust port during the casting process, nodular graphite iron proximate the chill device around the exhaust port core, and forming the thermally isolated exhaust port containing nodular graphite iron in the cylinder head.

An engine includes at least one cylinder, a first intake valve and a second intake valve associated with the cylinder, to control a flow of intake air from a first intake duct and a second intake duct, respectively. The two intake ducts communicate with a common intake manifold, so as to receive air at the same pressure. During the intake stage, in each cylinder operating cycle, initially an opening and closing movement of only the first intake valve is activated, while the second intake valve remains closed and, subsequently, an opening and closing movement of only said second intake valve is activated, while the first intake valve remains closed. In this way, the two air flows at the same pressure entering the cylinder give rise to a high turbulent kinetic energy, to the advantage of combustion efficiency and reduction of harmful exhaust emissions.

A combustion chamber structure in which an installation hole of the injector is improved to realize a rapid combustion and to reduce an unburned hydrocarbon. In the combustion chamber, a leading end of an injector is withdrawn from an upper end of an opening of an installation hole, and an additionally expanded surface area is formed on an upper inner surface of the installation hole from a portion to which the leading end of the injector is situated. to an opening end of the installation hole. An angle between the additionally expanded surface area and a joint surface of a cylinder head is narrower than an angle between a center axis of the installation hole and the joint surface.

A shut-off member for a turbocharger for an internal combustion engine includes a first channel, a second channel, and a wall that separates the first channel from the second channel. A shut-off member opening is formed in the wall that connects the first channel and the second channel. The shut-off member opening is selectively openable and closable by a shut-off member body. A cooling channel is disposed in the wall and at least partially surrounds the shut-off member opening.

A cylinder head includes: an exhaust port configured to lead out exhaust gas from combustion chamber; an intake port configured to introduce fresh air into the combustion chamber; and an EGR gas passage in which EGR gas flows, wherein exhaust outlets of the exhaust port and an EGR gas inlet of the second EGR pipe are located on a first side of the cylinder head and, and a fresh air inlet communicated to the intake port and an EGR gas outlet of the EGR gas passage are located on a second side which is opposite from the first side.

A cylinder head includes: an exhaust port configured to lead out exhaust gas from combustion chamber; an intake port configured to introduce fresh air into the combustion chamber; and an EGR gas passage in which EGR gas flows, wherein exhaust outlets of the exhaust port and an EGR gas inlet of the second EGR pipe are located on a first side of the cylinder head and, and a fresh air inlet communicated to the intake port and an EGR gas outlet of the EGR gas passage are located on a second side which is opposite from the first side.

A method of forming a thermally isolated exhaust port, the method comprising applying an endothermic material to an exhaust port core in a mold for an engine cylinder head, forming the engine cylinder head with an exhaust port using a casting process, generating, in the cylinder head with the exhaust port during the casting process, nodular graphite iron proximate the endothermic material around the exhaust port core, and forming the thermally isolated exhaust port containing nodular graphite iron in the cylinder head.

A combustion system is provided for an internal combustion engine including a cylinder head and a piston. In one example, a combustion system may include a cylinder head with a second cylinder surface angled relative to a first cylinder surface, an intake port coupled to the first cylinder surface, an exhaust port coupled to the second cylinder surface, and a piston with a first piston surface parallel to the first cylinder surface and a second piston surface parallel to the second cylinder surface.

A first coolant flow passage is provided to extend in a longitudinal direction of a cylinder head. In at least one of cross sections perpendicular to the longitudinal direction, the first coolant flow passage is located between a flat plane including central axes of a plurality of combustion chambers and parallel to the longitudinal direction and a central line plane including central lines of a plurality of intake ports. In at least one of cross sections perpendicular to the longitudinal direction, at least a portion of a second coolant flow passage is located between the combustion chamber and the first coolant flow passage. A coolant at a temperature lower than that of a coolant flowing in the second coolant flow passage flows in the first coolant flow passage.