A pivoting piston machine includes a housing, a first piston and a second piston arranged in the housing, the first and second pistons being pivotable away from one another and toward one another about a pivot axis. The machine has a working chamber arranged between first and second piston. The working chamber increases and decreases in size in alternating fashion during pivoting of the first piston and of the second piston. The machine also has a inlet mouth for admission and discharge of the working medium. A closing element for closing and opening the inlet or the outlet has a valve disk interacting with a valve seat. Either the inlet mouth or the outlet mouth is arranged within the working chamber between the first end surface and the second end surface, and the valve seat and the valve disk are arranged at either the inlet mouth or the outlet mouth.

A rocker arm can comprise a first outer arm and a second outer arm joined by a pivot body. An actuatable latch mechanism is within the pivot body. An inner arm assembly comprises a latch arm. A first spring prop is on the inner arm assembly distal from the latch arm. An axle joins the inner arm assembly to pivot between the first outer arm and the second outer arm. A spring is biased against the first outer arm and against the first spring prop. The first spring prop can comprise a hooked end. Or, the first spring prop can extend laterally out from the rocker arm and parallel to the axle. The spring can comprise a one-piece spring comprising first and second coil springs connected by a lateral connector. Or, two separate torsion springs can comprising tangential spring ends extending at approximately 90 degrees.

A rocker arm can comprise a first outer arm and a second outer arm joined by a pivot body. An actuatable latch mechanism is within the pivot body. An inner arm assembly comprises a latch arm. A first spring prop is on the inner arm assembly distal from the latch arm. An axle joins the inner arm assembly to pivot between the first outer arm and the second outer arm. A spring is biased against the first outer arm and against the first spring prop. The first spring prop can comprise a hooked end. Or, the first spring prop can extend laterally out from the rocker arm and parallel to the axle. The spring can comprise a one-piece spring comprising first and second coil springs connected by a lateral connector. Or, two separate torsion springs can comprising tangential spring ends extending at approximately 90 degrees.

A valve assembly for an engine includes a gas exchange valve, a valve guide, and a seal. The gas exchange valve includes a valve stem. The valve guide includes an outer surface having a stem seal retention surface disposed at a seal end thereof. The valve stem extends through the valve guide such that the valve is reciprocally movable over a range of travel along the longitudinal axis with respect thereto. The seal is mounted to the stem seal retention surface of the valve guide such that the seal is in running, sealing engagement with the valve stem. The stem seal retention surface includes a shoulder surface to help retain the seal.

A moment-cancelling, four-stroke engine is disclosed. The engine includes a first cylinder having a first piston and a second cylinder having a second piston, a first crankshaft operably connected to the first piston and a second crankshaft operably connected to the second piston. The first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction that is opposite the first direction to cancel the moments applied to the engine and reduce engine vibration.

One exemplary embodiment of the present disclosure relates to an engine intake port structure. According to the engine intake port structure of the exemplary embodiment of the present disclosure, a chamfer is formed to be offset to either side from an end corner of an intake port. Accordingly, the inflow of a fuel gas is concentrated on a side in which an opening width of the chamfer is wide at the beginning of an opening stage when the intake port is opened/closed by a valve unit, and after the intake port is opened, the opening width is formed to be similar at four sides of the valve unit such that swirls formed in the fuel gas is weakened. That is, complete combustion of the fuel can be anticipated since the length of time during which the fuel gas remains in a combustion chamber is extended.

A method for manufacturing a metallic component including the steps of providing a capsule, which defines at least a portion of the shape of the metallic component, arranging metallic material in the capsule, sealing the capsule, subjecting the capsule to Hot Isostatic Pressing for a predetermined time, at a predetermined pressure and at a predetermined temperature, and optionally, removing the capsule. The metallic material is at least one pre-manufactured coherent body, which pre-manufactured coherent body being made of metallic powder, wherein at least a portion of the metallic powder is consolidated such that the metallic powder is held together into a pre-manufactured coherent body. At least one portion of the pre-manufactured coherent body is manufactured by Additive Manufacturing by subsequently arranging superimposed layers of metallic powder.

A method for manufacturing a metallic component including the steps of providing a capsule, which defines at least a portion of the shape of the metallic component, arranging metallic material in the capsule, sealing the capsule, subjecting the capsule to Hot Isostatic Pressing for a predetermined time, at a predetermined pressure and at a predetermined temperature, and optionally, removing the capsule. The metallic material is at least one pre-manufactured coherent body, which pre-manufactured coherent body being made of metallic powder, wherein at least a portion of the metallic powder is consolidated such that the metallic powder is held together into a pre-manufactured coherent body. At least one portion of the pre-manufactured coherent body is manufactured by Additive Manufacturing by subsequently arranging superimposed layers of metallic powder.

A method for manufacturing an internally cooled valve (2), includes providing a valve body (4) having a valve stem (6) that ends in a valve head (8). The valve body (4) has a cavity (10) that is open toward the valve head (8) and with a valve base element (12) by friction welding the valve base element (12) to the valve head (8). The valve bottom element (12) is preferably a sintered component.

A method for manufacturing a poppet valve or mushroom valve includes providing a mixture of metal powder and a binder, filling and pressing said mixture in a mold, to obtain a green product, removing the binder from the green product, and thermally sintering the green product to a poppet valve blank, by hot isostatic pressing. A poppet valve is also provided that is manufactured with this method.