An internal combustion engine has a plurality of cylinders and transmission arranged adjoining the engine. If designating an average height of a combustion chamber in a region inside from a virtual cylindrical surface passing through center of a valve body of an intake valve and extending in a circumferential direction of each cylinder when a piston is at top dead center, as center height, and designating average of a height of the combustion chamber in a region outside from the virtual cylindrical surface when the piston is at top dead center, as peripheral height, the combustion chambers form a center height of a transmission side cylinder positioned most to the transmission side among the plurality of cylinders is higher than center heights of usual cylinders including one cylinder other than the transmission side cylinder and a peripheral height at the transmission side cylinder lower than peripheral heights of usual cylinders.

A traction drive system for a vehicle includes a housing, a high-speed motor, a motor controller, a transmission, a cooling system, and a lubricating oil system. The housing defines a motor cavity, an electronics cavity, an oil cavity, and a cooling fluid cavity. The cooling fluid cavity is thermally coupled to each of the motor, electronics, and oil cavities. The high-speed motor is substantially within the motor cavity and coupled to a lubricating oil system fluidically coupled to the oil cavity. The motor controller includes electronics within the electronics cavity. The transmission is mechanically coupled to the high-speed motor and coupled to the lubricating oil system fluidically coupled to the oil cavity. The cooling system is fluidically coupled to the cooling fluid cavity and configured to cool the high-speed motor, the motor controller, and the lubricating oil system.

A two-wheeled vehicle is provided including a frame, front and rear ground-engaging members each supporting the frame, a straddle-type seat, a handlebar for steering the vehicle, at least one light device configured to operate in a hazard mode, an engine supported by the frame and operably coupled to the ground-engaging members, a tilt sensor, and a vehicle control unit in communication with the tilt sensor. The vehicle control unit is operative to detect a tilt angle of the vehicle based on output from the tilt sensor. The vehicle control unit is operative to determine a tip-over condition of the vehicle based on the detected tilt angle exceeding a threshold tilt angle. The vehicle control unit activates the hazard mode of the at least one light in response to the determination of the tip-over condition.

The disclosure provides rotary machines that include, in one embodiment, a shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first gearbox disposed thereon defining one or more cavities therein. At least one contour is slidably received into an arcuate cavity in an exterior surface of the gearbox. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume. A gearbox mechanism consisting of gears, crankshafts, bearings and connecting rod creates an oscillatory motion 2 times per revolution such that the contour can navigate about the arcuate cavity without contacting the cavity at a high rate of rotating speed. Thus, said working volume can expand and compresses twice per rotatable shaft revolution.

A vehicle power unit is disclosed which prevents a transmission apparatus from becoming large in size and promotes reduction in size by reducing the number of parts. A transmission shift drum has a driven gear mounted on a shift drum rotary shaft portion on one end of the shift drum. An extended support wall is formed to extend to outside in a vehicle width direction in parallel with a first case side wall of a crankcase. The case side wall supports the first drum rotary shaft portion on which the driven gear is mounted. The extended support wall and the first case side wall support thereon gears of a reduction gear train between a drive gear of a shift motor mounted on the extended support wall and the driven gear.

A traction drive system for a vehicle includes a housing, a high-speed motor, a motor controller, a transmission, a cooling system, and a lubricating oil system. The housing defines a motor cavity, an electronics cavity, an oil cavity, and a cooling fluid cavity. The cooling fluid cavity is thermally coupled to each of the motor, electronics, and oil cavities. The high-speed motor is substantially within the motor cavity and coupled to a lubricating oil system fluidically coupled to the oil cavity. The motor controller includes electronics within the electronics cavity. The transmission is mechanically coupled to the high-speed motor and coupled to the lubricating oil system fluidically coupled to the oil cavity. The cooling system is fluidically coupled to the cooling fluid cavity and configured to cool the high-speed motor, the motor controller, and the lubricating oil system.

A vehicle includes three pairs of wheels, each pair being spaced apart in a right-left direction, three differential gears, respectively corresponding to the three pairs of wheels, and an engine that generates a rotation to be transmitted to the three pairs of wheels through the three differential gears. The engine is located rearward of a front differential gear that is any one of the three differential gears and is fixed to the front differential gear.

A combination of an engine, a gearbox clutch housing and a mounting system for mounting the combination to the structural load-bearing components of a vehicle, comprising an engine having a first contact surface; a gearbox clutch housing having a second contact surface, the first contact surface of the engine and the second contact surface of the gearbox clutch housing each being joined to the other by mechanical fastening means; and a first hanger, where the latter comprises a rigid plate positioned between the first contact surface of the engine and the second contact surface of the gearbox clutch housing, with the first hanger being securely fastened between the engine and the gearbox clutch housing. The first hanger has first and second opposed load-transferring surfaces of closed perimeter, with the first of the load-transferring surfaces being in pressing contact with the first contact surface of the engine and the second of the load-transferring surfaces being in pressing contact with the second contact surface of the gearbox clutch housing. The first hanger includes one or more load-supporting members extending beyond the perimeter of the opposed load-transferring surfaces; and the one or more load-supporting members include plural spaced-apart fastening elements adapted for coupling to one or more select structural load-bearing components of a vehicle.

A transmission case 210 supports a shift shaft 222 that constitutes a part of a speed change operation mechanism 220, and which receives an operating input and transmits a speed change motion of a transmission 201. A part of a transmission holder 162M in which part the shift shaft 222 is disposed includes a shaft insertion opening portion 162g that the shift shaft 222 is disposed so as to pass through.

A drive unit for a straddled vehicle includes an engine main body unit, a transmission unit, and a shared lubrication oil supply mechanism. The shared lubrication oil supply mechanism includes a first booster pump which pressurizes the shared lubrication oil lubricating both the engine main body unit and the transmission unit and a second booster pump which pressurizes at least part of the shared lubrication oil which has been pressurized by the first booster pump and which is in a positive pressure condition.