An intake system is arranged in a side portion of one side of an engine body in a left-right direction, and the exhaust passage and the air pump are arranged in a side portion of the other side of the cylinder block and the cylinder head of the engine body in the left-right direction.

A linear reciprocating engine may include an engine block, a cylinder having combustion chambers at opposing ends, cylinder heads located at an end of the respective combustion chambers, respectively, and a double-faced piston. The engine may further include piston rod portions extending from both faces of the piston through the combustion chambers. The engine may further include an exhaust outlet in a peripheral cylinder wall and elongated channels in the piston rod portions being configured to serve as an intake inlet for gas from a location external to the cylinder. When the piston is in a combustion stage in a first combustion chamber, the piston blocks the exhaust outlet from communicating with the first chamber with the first channel access opening outside the first chamber, while simultaneously the exhaust outlet is in communication with a second combustion chamber with the second channel access opening within the second chamber.

An internal combustion engine may include an engine block, a cylinder within the engine block, and a piston within the cylinder. The piston may have an outer peripheral wall, and a groove in the outer peripheral wall of the piston may have a first edge and a second edge spaced from the first edge. The piston may have a piston ring in the groove, and the piston ring may have a shape that meanders within the groove, such that the shape of the piston ring differs from a shape of the groove and such that the piston ring does not substantially fill the groove. The piston ring may be constructed of a material that when subjected to heat causes a shape of the meanderings to change, thereby enabling the piston ring to expand in an axial direction of the piston, between the edges of the groove.

A linear reciprocating engine may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The engine may further include a first piston rod portion extending from a first face of the double-faced piston through the first combustion chamber, and a second piston rod portion extending from a second face of the piston through the second combustion chamber. Passageways in the piston rod portions may be configured to communicate gases between the combustion chamber and a location outside the cylinder and configured to prevent gases from being exchanged between the cylinder and a location outside the cylinder via a path that crosses both face of the piston.

An outboard marine engine comprises a vertically aligned bank of piston-cylinders; a camshaft that operates a plurality of valves for controlling flow of air with respect to the vertically aligned bank of piston-cylinders, the camshaft vertically extending between a lower camshaft end and an upper camshaft end; and a cam lobe at the upper camshaft end. Rotation of the camshaft causes the cam lobe to cam open an uppermost valve in the plurality of valves. A lubricant circuit extends through the camshaft and has a lubricant outlet located at the upper camshaft end. The lubricant outlet is configured to disperse lubricant onto the uppermost valve, which is located above an uppermost cam bearing bulkhead for the upper camshaft end.

Car having: a first axle having two first drive wheels; a second axle having two second drive wheels; an internal combustion engine, which is provided with a plurality of cylinders, where respective pistons slide on the inside, and with a drive shaft connected to the pistons and oriented longitudinally; a transmission shaft, which is oriented longitudinally and is configured to transmit the motion from the internal combustion engine to the first wheels; a gearbox provided with at least one primary shaft, which receives the motion from the drive shaft, and with at least one secondary shaft; a first epicyclic differential, which receives the motion from the secondary shaft of the gearbox and transmits the motion to the first wheels through the transmission shaft and to the second wheels; and a second epicyclic differential, which is coaxial to the two second wheels, is interposed between the first epicyclic differential and the second wheels, receives the motion from the first epicyclic differential and transmits the motion to the second wheels. The two differentials are arranged coaxial to each other.

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.

A linear reciprocating engine may include a cylinder having first and second combustion chambers at opposing ends, first and second cylinder heads at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The engine may further include an exhaust port located in a peripheral cylinder wall and at least one combustion gas inlet in a location other than the peripheral cylinder wall. The combustion gas inlet and the exhaust port may be configured to cooperate such that combustion gases introduced through the inlet are evacuated from the cylinder through the exhaust port. The double-faced piston may have an axial length from one face to an opposite face of the piston less than or equal to of a distance from at least one of the first cylinder head and the second cylinder head to the exhaust port.

An internal combustion engine for a vehicle includes: an oil tank defining an oil reservoir; a pump to pump oil from the oil reservoir to lubricate parts of the engine; and a cyclonic separator disposed within the oil tank and configured to separate gas from oil received therein, the cyclonic separator defining an internal separator chamber for circulation of oil therein, the cyclonic separator comprising: a vortex forming portion configured to cause oil flowing therethrough within the internal separator chamber to define a spiral path in order to separate at least part of a gas content therefrom; an oil inlet for receiving oil into the internal separator chamber, the oil inlet being fluidly connected to the pump; an oil outlet for discharging oil from the internal separator chamber and into the oil reservoir of the oil tank; and a gas outlet for discharging gas from the internal separator chamber.

A method of operating a fan for an air-cooled internal combustion engine includes starting the air-cooled internal combustion engine, operating the fan in a first operating mode in which the fan rotates in a first direction, and operating the fan in a second operating mode in which the fan rotates in a second direction.