Internal combustion engines having multi-stage telescoping poppet valves in lieu of conventional poppet valves are disclosed. The engines may have pistons with a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston heads may include one or more depressions and may be domed to facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

An internal combustion engine that includes an oil baffle in the oil sump. The internal combustion engine may include a crankcase comprising an oil sump containing an oil reservoir, a crankshaft, and an oil baffle positioned within the oil sump. The crankshaft may be a vertical crankshaft and a first balance shaft may extend upward from the oil baffle. The crankshaft may be positioned within the oil baffle and a drivetrain may, also optionally, be positioned in the oil baffle. The internal combustion engine may be configured such that the oil reservoir has a first oil level when the internal combustion engine is off and a second oil level when the internal combustion engine is running at normal operating conditions. The first oil level is above a floor of the oil baffle. The second oil level may, also, be above the floor of the oil baffle.

Aspects of the disclosure are directed to a shaft configured with a first hole, a bearing race coupled to the shaft and configured with a second hole and a third hole, and an oil scoop configured to receive oil and provide the oil to the shaft, where the first and second holes are oriented axially with respect to the shaft, and where the third hole is oriented radially with respect to the shaft. In some embodiments, a second oil scoop is configured to receive oil and provide the oil to the shall. The oil scoop and the second oil scoop may be concentric with respect to one another.

Aspects of the disclosure are directed to a shaft configured with a first hole, a bearing race coupled to the shaft and configured with a second hole and a third hole, and an oil scoop configured to receive oil and provide the oil to the shaft, where the first and second holes are oriented axially with respect to the shaft, and where the third hole is oriented radially with respect to the shaft. In some embodiments, a second oil scoop is configured to receive oil and provide the oil to the shall. The oil scoop and the second oil scoop may be concentric with respect to one another.

A power system includes: a rotating body; a housing that accommodates the rotating body; and a storage portion that is provided in a bottom of the housing to store a liquid medium. The rotating body is partially located in the storage portion, and an inner surface of the housing includes a protrusion that extends above the rotating body to intersect with a rotation direction of the rotating body.

A power system includes: a rotating body; a housing that accommodates the rotating body; and a storage portion that is provided in a bottom of the housing to store a liquid medium. The rotating body is partially located in the storage portion, and an inner surface of the housing includes a protrusion that extends above the rotating body to intersect with a rotation direction of the rotating body.

An internal combustion engine having an internal space including a crankcase chamber includes an oil tank, a first passage communicating a lower part of the internal space with a gas phase part of the oil tank, a first check valve provided in the first passage to permit a flow from the internal space to the oil tank, a second passage communicating the gas phase part with the internal space, a second check valve provided in the second passage to permit a flow from the second passage to the internal space, a third passage communicating a liquid phase part of the oil tank with the second passage, a third check valve provided in the third passage to permit a flow from the oil tank to the second passage, and a flow regulator valve provided in the third passage for regulating a flow of lubricating oil flowing through the third passage.

An internal combustion engine having an internal space including a crankcase chamber includes an oil tank, a first passage communicating a lower part of the internal space with a gas phase part of the oil tank, a first check valve provided in the first passage to permit a flow from the internal space to the oil tank, a second passage communicating the gas phase part with the internal space, a second check valve provided in the second passage to permit a flow from the second passage to the internal space, a third passage communicating a liquid phase part of the oil tank with the second passage, a third check valve provided in the third passage to permit a flow from the oil tank to the second passage, and a flow regulator valve provided in the third passage for regulating a flow of lubricating oil flowing through the third passage.

An internal combustion engine that includes an oil baffle in the oil sump. The internal combustion engine may include a crankcase comprising an oil sump containing an oil reservoir, a crankshaft, and an oil baffle positioned within the oil sump. The crankshaft may be a vertical crankshaft and a first balance shaft may extend upward from the oil baffle. The crankshaft may be positioned within the oil baffle and a drivetrain may, also optionally, be positioned in the oil baffle. The internal combustion engine may be configured such that the oil reservoir has a first oil level when the internal combustion engine is off and a second oil level when the internal combustion engine is running at normal operating conditions. The first oil level is above a floor of the oil baffle. The second oil level may, also, be above the floor of the oil baffle.

The present utility model discloses a portable four-stroke engine, comprising: an engine body, a flywheel and an oil storage tank, wherein an air valve distribution chamber and a crank shaft chamber are arranged in the engine; a crank shaft is arranged in the crank shaft chamber, and is connected to the flywheel; the oil storage tank is arranged on the engine body, located above the flywheel, and configured to store lubricating oil; a cam and a rocker arm mechanism are arranged in the air valve distribution chamber; and the cam is configured to drive the rocker arm mechanism. The portable four-stroke engine provided by the present utility model has a small volume and therefore has better operation performance.