An internal combustion engine includes a hollow cylinder, a piston within the hollow cylinder, and a cylinder head. A base valve assembly at a base of the hollow cylinder permits or restricts fluid flow from an intake manifold into a sub-chamber below the piston. The piston includes at least one intake port connecting a combustion chamber above the piston with the sub-chamber, and a transfer valve that opens and closes the at least one intake port. When the transfer valve opens the at least one intake port, fluid is permitted to flow from the sub-chamber to the combustion chamber. The internal combustion engine operates according to a four-stroke piston cycle, wherein multiple intake stages are provided. The intake stages may include intake of air into the sub-chamber during a compression stroke, transfer of air from the sub-chamber to the combustion chamber during a power stroke, intake of air-fuel mixture into the sub-chamber during an exhaust stroke, and transfer of air-fuel mixture from the sub-chamber to the combustion chamber during an intake stroke.

An engine includes a cylinder head, an ignition plug disposed in the cylinder head, a head partition wall disposed on the cylinder head to surround a periphery of the ignition plug, an injector disposed in the cylinder head and having an injection hole exposed outside the head partition wall, a cylinder block coupled to the cylinder head, a cylinder formed in the cylinder block, a piston disposed in the cylinder, and a piston partition wall disposed on a crown surface of the piston to face the head partition wall in a sliding direction of the piston. The height of the piston partition wall from the crown surface on the side closer to the injector is less than the height of the piston partition wall from the crown surface on the side farther from the injector.

A cylinder having at least one intake port and at least one exhaust port, wherein the at least one intake port includes an upper surface and a lower surface, the upper surface of the intake port having an entrance portion and an outlet portion, the upper surface arced from the entrance portion to the outlet portion.

A method for manufacturing a cylinder head includes: preparing a cylinder head casting having an intake passage, an exhaust passage, and a combustion chamber by casting using a mold and a plurality of cores; machining an intake port, an intake valve seat, an intake valve guide bore, an exhaust port, an exhaust valve seat, and an exhaust valve guide bore in the cylinder head casting by a first cylindrical tool; and forming a tapered surface on a portion of edge of the intake port by a second cylindrical tool. In particular, the second cylindrical tool moves along a predetermined trajectory at the edge portion of the intake port and rotates around an axis simultaneously to machine the tapered surface.

A structure of a combustion chamber for an engine includes a crown surface of a piston, a cylinder wall surface, a combustion chamber ceiling surface, and an ignition plug which includes an ignition portion. The crown surface of the piston includes: a cavity recessed in the cylinder axis direction; a parallel surface portion which is in parallel to a corresponding region on the combustion chamber ceiling surface at a position above the cylinder axis direction with a gap, when the piston is at a compression top dead center; and an inclined surface portion formed to continue to the parallel surface portion in such a way as to be directed to the ignition plug, when the piston is at a compression top dead center. The parallel surface portion and the corresponding region, in combination, constitute a squish flow generation portion generating a squish flow when the piston is lifted.

An internal combustion engine includes an auxiliary chamber bulkhead, the auxiliary chamber bulkhead including: a peripheral wall portion that is inserted in a vertical hole extending from a combustion chamber along a reference axis and that is in contact with an inner wall of the vertical hole about the reference axis; and a bottom wall portion that is continuous from the peripheral wall portion and that bulges from the vertical hole toward the combustion chamber, the peripheral wall portion and the bottom wall portion defining an auxiliary chamber that communicates with the combustion chamber. An ignition plug is disposed above the peripheral wall portion along the reference axis. A fuel injection valve is disposed in a position inclined with respect to the reference axis toward an opening formed in an inner surface of the peripheral wall portion.

An internal combustion engine 5 includes an intake valve spring 60 including a closely-wound section 62 and a sparsely-wound section 63. The closely-wound section 62 is provided so that elemental wire portions thereof are closely in contact with each other in the direction of the coil axial line L1 while an intake valve closes an intake port. The sparsely-wound section 63 is provided so that elemental wire portions thereof are spaced apart from each other in the direction of the coil axial line L1 while the intake valve closes the intake port. The coil outer diameter D62 of at least a part of the closely-wound section 62 is smaller than the coil outer diameter D63 of at least a part of the sparsely-wound section 63.

A hydraulic lash adjuster for use in diesel engines including a cylinder head having a first valve, a second valve, and a valve bridge extending between and in contact with both the first valve and the second valve. Where the diesel engine includes a first rocker arm, and where at least one of the first valve and the second valve undergo an oil can valve deflection rate. The hydraulic lash is configured to selectively transmit force between the first rocker arm and the valve bridge, and where the hydraulic lash adjuster is normally in the open configuration, and where the hydraulic lash adjuster changes from the open configuration to a closed configuration at a critical velocity that is greater than the oil can valve deflection rate.

There is provided a water cooled engine including a cylinder head with minimized thermal strain.

A head water jacket includes an inter-exhaust-port-wall water channel between a first exhaust entrance port wall and a second exhaust entrance port wall. A cylinder head includes a cooling water injection passage provided at a bottom wall of the cylinder head. The cooling water injection passage is positioned on the exhaust end side, and includes a passage entrance provided on the exhaust end side, and a passage exit directed toward the inter-exhaust-port-wall water channel. An exhaust port wall includes a heat dissipation fin extending from a first exhaust entrance port wall toward an exhaust end. The space between the heat dissipation fin and a second exhaust entrance port wall forms a water channel entrance of the inter-exhaust-port-wall water channel.

An engine line is described herein that includes a first engine including a front end accessory drive system and a second engine including a greater number of cylinders than the first engine and a front end accessory drive system. The engine line further includes a generator, in different manufacturing arrangements, mounting to each of the front engine accessory drive systems in the first and second engines in a common location.