An oil pan disposed underneath an engine of a motorcycle and configured to reserve engine oil includes a shallow bottom portion and a deep bottom portion formed to extend in a front-rear direction of the motorcycle substantially at a center in a left-right direction of the motorcycle of the shallow bottom portion, and to become deeper than the shallow bottom portion, and in which a space defined in the left-right direction of the motorcycle between both side wall portions of the deep bottom portion that face each other in the left-right direction of the motorcycle is formed to increase as the deep bottom portion extends from a front toward a rear thereof with respect to the motorcycle.

A small internal combustion engine includes a housing and an internal combustion engine body arranged in the housing. The internal combustion engine body includes a cylinder, a crankcase, a piston arranged in the cylinder, a crankshaft arranged in the crankcase and driving the piston, and an oil pan arranged at a bottom of the crankcase. The oil pan has an oil pan inlet, and the housing has a housing oil inlet. A hose connected to the oil pan inlet and the housing oil inlet forms a fluid passage for lubricating oil to flow from the housing oil inlet to the oil pan. A related garden tool includes a power source assembly that drives a working assembly to operate via a power transmission assembly.

To minimize the risk of damaging an internal oil passage for conducting oil, the lower structure of an internal combustion engine includes a bottom wall (6), a side wall (7) provided along a peripheral edge of the bottom wall to define the oil chamber in cooperation with the bottom wall, a device mounting seat (52) provided on the side wall and configure to have a prescribed device (51) attached thereto; and an oil passage portion (57) formed in the side wall to define the oil passage (56), wherein the oil passage opens at the device mounting seat, and a part of the side wall adjacent to the oil passage portion is provided with a load absorbing portion (61) configured to be more readily deformable than the oil passage portion.

An internal combustion engine unit including an internal combustion engine body, a balancer device attached to a lower portion of the internal combustion engine body, and an oil pan attached to the lower portion of the internal combustion engine body so as to surround the balancer device. The balancer device is disposed facing an outlet of an oil outflow hole, and the oil outflow hole is formed in the internal combustion engine body so as to return a lubricating oil in the internal combustion engine body to the oil pan.

An oil pan may include a pan body forming a dual chamber including a primary chamber and a secondary chamber, and a mesh. The primary chamber and the secondary chamber each contains a different amount of oil, and the mesh allows a different amount of oil permeation discharged from the secondary chamber to the primary chamber based on temperature of the oil.

A small internal combustion engine includes a housing and an internal combustion engine body arranged in the housing. The internal combustion engine body includes a cylinder, a crankcase, a piston arranged in the cylinder, a crankshaft arranged in the crankcase and driving the piston, and an oil pan arranged at a bottom of the crankcase. The oil pan has an oil pan inlet, and the housing has a housing oil inlet. A hose connected to the oil pan inlet and the housing oil inlet forms a fluid passage for lubricating oil to flow from the housing oil inlet to the oil pan. A related garden tool includes a power source assembly that drives a working assembly to operate via a power transmission assembly.

An engine includes a crankcase in which a crank chamber that houses a crankshaft is formed, a cylinder block that is attached to the crankcase, and a cylinder that is formed with a sliding surface with respect to a piston. The crankcase includes a partition wall that forms the crank chamber. A lower end of the cylinder protrudes into the crank chamber from a lower end of the cylinder block, and a communicating hole that connects inside and outside of the cylinder is formed on a side surface of the cylinder as viewed in an axial direction of the crankshaft. The partition wall is formed with an opening that is communicated with the communicating hole.

A lubricating oil discharge and filling structure of an oil pan including a cylindrical lubricating oil amount adjustment wall vertically provided from a bottom surface of the oil pan, and having a lubricating oil amount adjustment passage communicating with an outside of the oil pan, formed on an inner periphery. The lubricating oil amount adjustment wall has a lubricating oil discharge hole formed in a lower part, to the lubricating oil amount adjustment passage, a cylindrical lubricating oil amount adjustment plug in which a communication hole that communicates with the lubricating oil amount adjustment passage is formed is assembled movably along the lubricating oil amount adjustment passage. The lubricating oil amount adjustment plug includes a screw portion that screws into a screw groove formed in the lubricating oil amount adjustment passage, and a sealing wall that seals discharge of the lubricating oil from the lubricating oil discharge hole.

A lubricating device for lubricating an internal combustion engine irrespective of orientation, which device comprises a housing that forms a housing part of the internal combustion engine, is, in order to make it possible to reliably lubricate an internal combustion engine, irrespective of orientation, by means of simple constructive means, designed and developed such that a first working chamber for storing lubricant and a second working chamber that is separate from the first working chamber are arranged in the housing, such that a passage is formed from the first working chamber to the second working chamber, such that the second working chamber comprises an opening to a crankshaft receiving area of the housing, and such that the first working chamber comprises a lubricant channel to the crankshaft receiving area, the opening and the lubricant channel being spaced apart from each other in a height direction such that lubricant can be supplied to the crankshaft receiving area, irrespective of orientation, at least via the opening or the lubricant channel.

An oil pan disposed underneath an engine of a motorcycle and configured to reserve engine oil includes a shallow bottom portion and a deep bottom portion formed to extend in a front-rear direction of the motorcycle substantially at a center in a left-right direction of the motorcycle of the shallow bottom portion, and to become deeper than the shallow bottom portion, and in which a space defined in the left-right direction of the motorcycle between both side wall portions of the deep bottom portion that face each other in the left-right direction of the motorcycle is formed to increase as the deep bottom portion extends from a front toward a rear thereof with respect to the motorcycle.