A standby generator includes an engine including an output shaft, an alternator, and an enclosure including a base and a number of walls extending from the base including a front wall, a rear wall, a first wall, and a second wall. The standby generator includes an intake opening configured to allow air to be drawn into the enclosure and an exhaust opening configured to allow heated air and exhaust gases to be expelled from the enclosure. The intake opening is provided on the rear wall proximate the first wall and the exhaust opening is provided on the front wall proximate the second wall. The air drawn into the enclosure at the first intake opening directly flows over the engine and is expelled through the exhaust opening.

An outboard motor includes an engine main body, and an intake device to supply air to the engine main body. The intake device includes a main intake pipe including a first intake pipe and a second intake pipe connected to a downstream end of the first intake pipe and extending at an angle with respect to an axial direction of the first intake pipe and through which the air supplied to the engine main body flows, and an extension pipe extending from a connection between the first intake pipe and the second intake pipe and including a resonance chamber therein. The extension pipe includes an extended peripheral wall and an end wall that closes the resonance chamber except for a portion adjacent to the main intake pipe.

In this air intake apparatus, a plurality of respective air intake ports include sealing surfaces that include inner wall surfaces with which valve bodies come into contact at the closed positions of the valve bodies, and the rotation angles of valve bodies located on a side relatively close to a drive source from their open positions to their closed positions are larger than the rotation angles of valve bodies located on a side relatively opposite to the drive source when a plurality of valve bodies are rotated from their open positions to their closed positions.

A standby generator includes an engine including an output shaft, an alternator, and an enclosure including a base and a number of walls extending from the base including a front wall, a rear wall, a left wall, and a right wall. The output shaft extends toward the alternator and the left wall. The standby generator includes an intake opening configured to allow air to be drawn into the enclosure and an exhaust opening configured to allow heated air and exhaust gases to be expelled from the enclosure. The intake opening is provided on the rear wall and the exhaust opening is provided on the front wall.

A front structure of a saddle ride type vehicle includes a headlight unit, a front cowl, and a middle cowl. At a position outside the headlight unit in the vehicle width direction, an air intake portion opening to the front side of the vehicle is formed between the front cowl and the middle cowl. The front cowl includes a partition wall configured to divide the air intake portion into an upper region and a lower region. The lower region forms an inlet of an air intake path of an air cleaner. The upper region forms a first wind guide path configured to discharge a traveling wind to the rear side of the front cowl.

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.

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.

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.