A cylinder structure of an internal combustion engine contains: a body, two lids, and multiple positioning elements. The body has a combustion chamber, an air inlet, an air outlet, and two scavenging units. A respective scavenging unit has a first scavenging orifice, a second scavenging orifice, a first fringe, a second fringe, a first engagement portion, and a first fixing orifice. The two lids are configured to close the first scavenging orifice and the second scavenging orifice, an air conduit is defined between a respective lid and an external fence of the body, and the respective lid has multiple second fixing orifices. A respective positioning element has a stem and at least one hook, the stem extends into the first engagement portion, and the stem is rotated so that the at least one hook contacts with the respective lid, and the respective lid is connected with the body.

An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.

An assembly method is provided by orienting a cylinder-head at a first orientation. A first plurality of spring caps and a first plurality of retainer keys are installed into the cylinder-head in the first orientation by a first robot. A first plurality of valves is installed into the cylinder-head in the first orientation by a second robot, into engagement with the first plurality of retainer keys. An end effector is provided with an actuator supported upon an adapter plate. A shaft extends from the actuator with a mating surface to engage a spring cap. Porting is provided through the shaft to convey pressurized air upon a plurality of retainer keys within the spring cap. A plurality of gripper fingers extend from the distal end of the shaft to grip a valve spring while retaining a spring cap between the valve spring and the mating surface of the shaft.

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.

An internal combustion engine comprising at least a crank case, which houses a cylinder, and a cylinder head, which is adapted to be coupled to the crank case, and a liquid cooling circuit, wherein the liquid cooling circuit comprises at least one inlet aperture and at least one outlet aperture, a lower cooling chamber housed in said cylinder head in a position adjacent to a flame deck of said cylinder head; an upper cooling chamber housed in said cylinder head above said lower chamber, so that said lower chamber is sandwiched between said upper chamber and said flame deck; wherein said inlet aperture is provided in said upper or lower chamber and said outlet aperture is provided in said lower or upper chamber, on a same side of the internal combustion engine, so that the cooling liquid runs in a substantially U-shaped path moving between said upper chamber and said lower chamber, transversely relative to a crankshaft of said engine.

The cylinder head includes an intake port communicating with a cylinder of a cylinder block, a cylinder head main body having an exhaust port communicating with the cylinder, and a rocker housing integrally formed on the cylinder head main body and an inner side of which is defined as a valve-system accommodating space. The rocker housing includes a lateral wall having a lateral wall main body and a base end portion which extends along a lower end of the lateral wall main body, connects the lateral wall main body to the cylinder head main body, and has a thickness thicker than that of the lateral wall body. A flow path which extends in an extending direction of the base end portion and through which a fluid flow is formed in the base end portion.

An internal combustion engine with a turbocharger according to an embodiment includes a cylinder block internally including a plurality of cylinders, a cylinder head disposed on top of the cylinder block, and internally including a plurality of exhaust flow passages through which exhaust air discharged from each of the plurality of cylinders flows, and the turbocharger including a rotational shaft, a turbine wheel, and a compressor wheel, the turbine wheel being disposed at one end of the rotational shaft, the compressor wheel being disposed at the other end of the rotational shaft. At least the turbine wheel of the turbocharger is arranged inside the cylinder head. The cylinder head internally includes a plurality of scroll passages for introducing the exhaust air flowing through the plurality of exhaust flow passages to the turbine wheel, the plurality of scroll passages including a first scroll passage for introducing the exhaust air from a first range in a circumferential direction of the turbine wheel to the turbine wheel, and a second scroll passage for introducing the exhaust air from a second range, which is different from the first range in the circumferential direction of the turbine wheel, to the turbine wheel.

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.

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 internal combustion engine comprising at least a crank case, which houses a cylinder, and a cylinder head, which is adapted to be coupled to the crank case, and a liquid cooling circuit, wherein the liquid cooling circuit comprises at least one inlet aperture and at least one outlet aperture, a lower cooling chamber housed in said cylinder head in a position adjacent to a flame deck of said cylinder head; an upper cooling chamber housed in said cylinder head above said lower chamber, so that said lower chamber is sandwiched between said upper chamber and said flame deck; wherein said inlet aperture is provided in said upper or lower chamber and said outlet aperture is provided in said lower or upper chamber, on a same side of the internal combustion engine, so that the cooling liquid runs in a substantially U-shaped path moving between said upper chamber and said lower chamber, transversely relative to a crankshaft of said engine.