A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

In a vehicle power unit having an internal combustion engine, a pair of power transmission gears for transmitting rotation of a crank shaft to a balancer shaft is arranged between a crankcase and a crankcase cover, and a fluid pump is provided on a power transmission gear shaft supporting a power transmission gear, by which the backlash between the crank shaft and the balancer shaft is reduced and the friction and the noise of the gears are restrained while achieving downsizing of the gears of the crank shaft and the balancer, weight reduction and downsizing of the power unit.

An engine power unit for a vehicle has a crankcase made up of tow left and right crankcase members, and a lubricant feed pump disposed in one crankcase member in such a fashion that one side surface of pump rotors of the feed pump lies on the mating surface of the crankcase members. The feed pump is mounted on one end of the shaft of the feed pump while a drive gear for rotating the shaft is disposed on the opposite end of the shaft. A lubricant oil filter to which oil is delivered from the feed pump is disposed on the other crankcase member. Thus, the structure for supplying lubricating oil is simplified, and the power unit is reduced in size in its entirety.

An auxiliary machine drive device for an engine includes a fuel pump including first and second sprockets mounted on a rear end surface of an engine body; a starter disposed below the fuel pump; a drive sprocket and a crankshaft sprocket fixed to a crankshaft; an oil pump including an oil pump sprocket disposed below the drive sprocket; an intake camshaft including an intake camshaft sprocket, and disposed on the upper side of the engine body than the fuel pump; a balancer drive shaft including a balancer shaft sprocket disposed on the exhaust side than the crankshaft and below the crankshaft; a first chain wound between the crankshaft sprocket and a first sprocket; a second chain wound between the intake camshaft sprocket and a second sprocket: and a third chain wound between the drive sprocket, the oil pump sprocket, and the balancer shaft sprocket.

A delivery device for a motor vehicle for delivering oil from an oil sump to a lubricating oil circuit of internal combustion engine has, as an oil pump, a double-stroke vane-type pump with positive guidance of vanes. A direct drive of the vane-type pump by means of the internal combustion engine is configured for an operating point P2. An increased or reduced oil demand is compensated by means of an activatable electric drive. A compact oil pump of very small dimensions may thus be used.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

This drive system for a motor vehicle includes a top end and a bottom end that are coupled together, a kinematic drive chain, a compressor, a main lubrication system, that includes a main circuit and a main pump, which supplies at least the bottom end with a main lubricant via the main circuit, and a secondary lubrication system, that includes at least one secondary circuit separated from the main circuit and at least one secondary pump separate from the main pump, the secondary pump supplying the top end and/or the compressor with a secondary lubricant via the secondary circuit. The secondary lubrication system includes at least one secondary actuator mechanically separate from the kinematic drive chain and that drives the secondary pump to supply the top end and/or the compressor with the secondary lubricant.

A balance shaft module includes a balance shaft for receiving a driving force from a crankshaft of an engine by a driving gear and rotating inside a balance shaft housing, an oil pump gear being geared with the driving gear to rotate along with the driving gear, an oil pump shaft having the oil pump gear press-fitted therein and rotating as the oil pump gear rotates, and an oil pump assembly mounted in the oil pump shaft and pumping oil as the oil pump shaft rotates, wherein a pair of support rings is provided at both side surfaces of the oil pump gear to support both side portions of the oil pump gear in the oil pump shaft.

A rotary engine having a crankshaft, a housing provided with lobe accommodating portions arranged to surround the crankshaft, and combustion chambers communicating with the lobe accommodating portions, a rotor rotatable eccentrically with respect to the crankshaft and provided with lobes continuously accommodated in the lobe accommodating portions, a housing cover provided with a bearing portion through which the crankshaft is inserted so as to be rotatably supported, and a lubricating unit to supply oil to the bearing portion, wherein the lubricating unit includes an oil pan to accommodate oil therein, an oil pump to pump up oil filled in the oil pan, and an oil supply passage having both ends located in the oil pump and the bearing portion, respectively, is provided. This structure may allow direct and effective lubrication of the bearing portion, and can employ a journal bearing.

In an internal combustion engine for a saddle riding vehicle, in which a gear transmission and a shift drum of a shift change device is stored in a crankcase, the gear transmission having a plurality of transmission shafts parallel to a crankshaft extending in a vehicle width direction, a single pump shaft common to first and second oil pumps is rotatably supported by the crankcase. First oil pump rotors of the first oil pump are disposed at a mating face of a pair of left and right crankcase half bodies. A second oil pump rotor of the second oil pump is disposed between a pump gear and the first oil pump and at a side surface, on a side opposite to the mating face, of one crankcase half body out of the pair of left and right crankcase half bodies, the pump gear being arranged in the pump shaft.