Patent attributes
Disclosed is a vehicle engine in which a crankcase is reduced in length in a crankshaft direction and in which the number of parts for an ignition signal detecting device is reduced, whereas rigidity and function of a one-way clutch for a starter mechanism is maintained. The one-way clutch is mounted on one end of a crankshaft, and a sensor of the ignition signal detecting device is positioned radially outside a cylindrical outer wall of a clutch outer component of the one-way clutch. The cylindrical outer wall of the clutch outer component includes a plurality of concave and convex parts as a signal output part in its circumferential direction, where each of the concave and convex parts extends in the crankshaft direction. The cylindrical outer wall includes an annular reinforced part having a thickness which is greater than that of a bottom wall forming the concave part.