In a cylinder lubrication system for a two-stroke engine, a plurality of lubricating oil supply openings (78) open out in the inner circumferential surface of the cylinder (42) at a point lower than a top ring (22b) of a piston (22) located at a bottom dead center. The lubricating oil supply openings are configured to provide a larger amount of lubricating oil in the thrust side and anti-thrust side of the cylinder than in a remaining part of the cylinder. Thereby, the consumption of lubricating oil and the emission of undesired substances can be minimized while providing an optimum lubrication of the sliding part between the piston and the cylinder.

Disclosed is a lubricating apparatus including an oil supply pipe connected to a gearbox of a gearing device for transmitting turning force of a blowdown turbine in the turbo compound system to a crankshaft to supply oil into the gearbox, a first oil supply opening formed to be transpierced at the bearing housing of a first bearing rotatably supporting a shaft of an output gear for outputting turning force in the turbo compound system to supply oil supplied from the gearbox to the first bearing, a sub-supply pipe connected to a gear case in which the output gear is embedded to supply oil to the gear case, and a second oil supply opening formed to be transpierced at the bearing housing of a second bearing rotatably supporting the shaft of the output gear to supply oil supplied through the sub-supply pipe to the second bearing.

An engine block, an engine subassembly, and method for providing and manufacturing an engine block. The engine block includes a plurality of cylinder barrels positioned in the engine block, at least one oil jacket channel formed in the engine block, and an oil inlet port positioned in a peripheral wall of the engine block and connected to the at least one oil jacket channel. The at least one oil jacket channel includes a plurality of curved channel sections. Each curved channel section in the plurality of curved channel sections extends about at least a portion of a circumferential portion of a respective cylinder barrel in the plurality of cylinder barrels. The at least one oil jacket channel extends between adjacent cylinder barrels of the plurality of cylinder barrels in the engine block.

An object of the present invention is to simplify portions of an oil supply passage which portions are formed at a cylinder block. An oil supply device according to the present invention includes a cylinder block, an oil pan, an oil pump, and an oil filter. Wall portions of the oil pan are coupled to wall portions of the cylinder block. An oil filter is attached to the oil pan. An upstream oil supply passage through which the oil filtrated by the oil filter flows is formed at the oil pan. A downstream oil supply passage including a main gallery extending in a cylinder column direction is formed at the cylinder block. A first communication passage through which the main gallery and the upstream oil supply passage communicate with each other is formed at the wall portion of the cylinder block and the wall portion of the oil pan.

To provide a supercharger mounting structure for an engine that enables a supercharger to be easily fitted to or removed from an engine main body, the supercharger mounting structure for the engine includes a supercharger including a compressing unit for supplying an intake air under pressure to the engine, a speed increasing unit for increasing the rotational speed of an engine rotary shaft and then transmitting it to the compressing unit and a supercharger casing for accommodating the compressing unit and the speed increasing unit. The supercharger casing is removably fitted to a crankcase of the engine.

A reciprocating machine incitides a cylinder including an internal cylinder wail, a piston movable in the cylinder between a top position and a. bottom position, the piston, comprising an upper ring pack and a lower ring pack disposed around a circumference of the piston and spaced from each other by a first distance, and a circumferential collector groove in the cylinder wall in a position that is above the lower ring pack when the piston is in the top position and that is below the upper ring pack when the piston is in the bottom position, the collector groove including at least one hole eonneciabie to a conduit for comieciion to a sump. A helical groove can also be provided in the cylinder wall.

A combustion engine includes a supercharger which pressurizes intake air to be supplied to an engine body. A lubrication system for the combustion engine includes a main lubrication passage through which lubricating oil flows to lubricate the engine body, a supercharger lubrication passage through which lubricating oil flows to lubricate the supercharger, and an oil pump which supplies a shared lubricating oil to both of the main and supercharger lubrication passages.

An internal combustion engine includes a piston, a cylinder that has a sliding surface on which the piston slides, and a piston pin that connects the piston and a connecting rod. The sliding surface has a shape in which the inner diameter of a central portion in the axial direction is larger than the inner diameter of an upper end portion, and the center of the piston pin is located at the center of the piston.

A piston includes a piston head, a piston skirt and an oil flow path. The piston skirt is provided on a bottom side with respect to the piston head, and a pin hole is formed along an extending direction crossing an up-and-down direction in the piston skirt. The oil flow path extends through the piston head and the piston skirt, and has an opening portion opening to the bottom side in the piston skirt. a dimension of the opening portion along the extending direction of the piston hole is greater than a dimension of the opening portion along a width direction crossing both the up-and-down direction and the extending direction of the pin hole.

An air intake system having a turbocharger and an intercooler provides combustion air for an internal combustion engine of an all-terrain vehicle. The all-terrain vehicle includes a straddle seat, and the he intercooler is mounted above the internal combustion engine. The intercooler has a plurality of pressurized air crosspipes defining an intercooler plane. An intercooler attack angle of the intercooler plane relative to horizontal is greater than or equal to 80 and less than 90. The air intake system includes an intake pressure relief system with a pressure sensor and a pressure relief valve. When the pressure sensor senses an onset of an overpressure event, the pressure relief valve is opened. The turbocharger housing is integrally formed with the exhaust manifold, and the exhaust manifold has flange gaps between exhaust intake ports, which allow thermal expansion difference between the cylinder head and the exhaust manifold.