Engine and straddle-type vehicles

Abstract

This invention provides an engine and a straddle-type vehicle that can reduce the power supply and precisely stop the crankshaft near the position of maximum intake reaction force. The engine of this invention includes a crankshaft, a motor generator, a power supply source, a control device, an exhaust valve, an exhaust valve spring, an intake valve, and an intake valve spring. The control device ensures that the power supplied in the latter half of the region between the position of maximum exhaust reaction force (where the reaction force of the intake valve spring acts in the opposite direction of rotation) is less than the power supplied in the first half of the region. This causes the forward-rotating crankshaft to stop near the position of maximum intake reaction force after passing the position of maximum exhaust reaction force, due to the reaction force of the intake valve spring in the opposite direction of rotation.

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