Control system for an infinitely variable transmission with an electromagnetic powder clutch

摘要

A control system for a belt-drive infinitely variable transmission. The transmission is connected to a crankshaft of an engine through an electromagnetic clutch. The control system is provided with an engine speed signal producing circuit, a vehicle speed producing circuit and an arithmetic circuit for controlling the clutch current flowing through the coil of the clutch in dependency on the engine speed signal and vehicle speed signal. The arithmetic circuit is so arranged as to cut off the clutch current when the engine speed decreases to a predetermined value which is slightly higher than an engine speed at which the engine stalls during shiftdown operation of the transmission.