Continuously variable transmission means for use in vehicles

Claim 1

A continuously variable transmission means for controlling a speed of an engine installed in a vehicle, comprising: a driving pulley including a fixed member and a movable member, said movable member being actuated by an hydraulic cylinder to form a V-shaped opening between the fixed and movable member; a driven pulley with another fixed member and another movable member, said another movable member being actuated by another hydraulic cylinder to form another V-shaped opening between said another fixed member and said another movable member; a flexible endless belt member spanning the pulleys such that the diameter of the pulleys can be varied relative to each other to result in different transmitting ratios; a throttle means for controlling an engine speed; a detecting means for detecting a basic frequency and a higher harmonic frequency of the engine in accordance with an operating condition of the engine; a storing means for storing a predetermined basic value; a comparison means for comparing the detected frequency with the stored predetermined basic value; and a control means for controlling the engine speed in response to said comparison means comparing the detected frequency with the stored basic value and thereafter changing the transmitting ratio between the driving and driven pulleys.