An electric vehicle includes a frame, a wheel coupled to the frame, and a battery assembly including a housing supported by the frame. The housing includes a top side and a bottom side opposite the top side. A drive assembly of the electric vehicle is at least partially enclosed within a drive housing unit. The drive assembly includes a motor configured to receive power from the battery assembly and a gear assembly configured to transmit torque from the motor to the wheel. The drive housing unit is positioned below the bottom side of the housing.

An electric vehicle includes a frame, a wheel coupled to the frame, and a battery assembly including a housing supported by the frame. The housing includes a top side and a bottom side opposite the top side. A drive assembly of the electric vehicle is at least partially enclosed within a drive housing unit. The drive assembly includes a motor configured to receive power from the battery assembly and a gear assembly configured to transmit torque from the motor to the wheel. The drive housing unit is positioned below the bottom side of the housing.

A bike includes a frame elongated in a longitudinal direction, a front fork rotatably engaged with a front wheel at a front end of the bike, a rear fork rotatably engaged with a rear wheel at a rear end of the bike, a handlebar supported for rotation at the front end of the frame for steering the bike, and a drive module configured to drive the rear wheel of the bike when operated selectively with power. The frame includes a down tube extending downward and rearward from the front end of the bike and a drive module enclosure formed at a second end of the down tube. The drive module enclosure defines a drive module receptacle that is open along the longitudinal direction of the bike. The drive module receptacle is sized to receive the drive module along the longitudinal direction of the bike.

A bike includes a frame elongated in a longitudinal direction, a front fork rotatably engaged with a front wheel at a front end of the bike, a rear fork rotatably engaged with a rear wheel at a rear end of the bike, a handlebar supported for rotation at the front end of the frame for steering the bike, and a drive module configured to drive the rear wheel of the bike when operated selectively with power. The frame includes a down tube extending downward and rearward from the front end of the bike and a drive module enclosure formed at a second end of the down tube. The drive module enclosure defines a drive module receptacle that is open along the longitudinal direction of the bike. The drive module receptacle is sized to receive the drive module along the longitudinal direction of the bike.

A saddle riding vehicle includes: a motor which is a driving power source; a battery which powers the motor; a duct which supplies incoming wind to the battery; and a rear fender which is disposed above a rear wheel and houses the battery. The rear fender includes, behind the battery, a discharge hole which discharges the incoming wind supplied by the duct.

A saddle riding vehicle includes: a motor which is a driving power source; a battery which powers the motor; a duct which supplies incoming wind to the battery; and a rear fender which is disposed above a rear wheel and houses the battery. The rear fender includes, behind the battery, a discharge hole which discharges the incoming wind supplied by the duct.

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit and a misfire determination unit. The misfire determination unit includes first to third determination units. The first determination unit determines whether or not the crankshaft rotation speed fluctuation physical quantity acquired by the crankshaft rotation speed fluctuation physical quantity acquisition unit is greater than a set physical quantity determination reference. The second determination unit determines whether or not a fluctuation pattern constituted by a physical quantity and the crankshaft rotation speed fluctuation physical quantity acquired at least before or after the physical quantity falls within a set misfire pattern range. The third determination unit determines whether a misfire determination is to be set as effective or not, based on results of determination by the first and second determination units.

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit and a misfire determination unit. The misfire determination unit includes first to third determination units. The first determination unit determines whether or not the crankshaft rotation speed fluctuation physical quantity acquired by the crankshaft rotation speed fluctuation physical quantity acquisition unit is greater than a set physical quantity determination reference. The second determination unit determines whether or not a fluctuation pattern constituted by a physical quantity and the crankshaft rotation speed fluctuation physical quantity acquired at least before or after the physical quantity falls within a set misfire pattern range. The third determination unit determines whether a misfire determination is to be set as effective or not, based on results of determination by the first and second determination units.

In an internal combustion engine, a gasket is disposed between joining surfaces of a cylinder block and a cylinder head, and a heat radiation rib that extends in a cylinder axis direction is formed on the cylinder block or the cylinder head. In such an internal combustion engine, the gasket includes: a portion to be sandwiched that is sandwiched between the joining surfaces; and an extending portion that protrudes toward an outside from the portion to be sandwiched as viewed in a cylinder axis direction.

In an internal combustion engine, a gasket is disposed between joining surfaces of a cylinder block and a cylinder head, and a heat radiation rib that extends in a cylinder axis direction is formed on the cylinder block or the cylinder head. In such an internal combustion engine, the gasket includes: a portion to be sandwiched that is sandwiched between the joining surfaces; and an extending portion that protrudes toward an outside from the portion to be sandwiched as viewed in a cylinder axis direction.