Apparatus for controlling actuating fluid pressure on vehicular friction clutch with compensation for decrease in friction coefficient at elevated temperature

摘要

A control apparatus provided with an electromagnetic valve assembly to selectively change the variation rate of a fluid pressure to actuate the clutch in dependence on the degree of opening of the throttle valve for the vehicular engine, a pulse-generating logic circuit governs the operational sequence of the electromagnetic valves, and a temperature sensor which includes a reed relay located close to the clutch, a permanent magnet attached to the flywheel of the clutch and a heat- sensitive element capable of varying the magnetic flux density passing through the reed relay when the temperature of the clutch disc exceeds a predetermined temperature. A monostable multivibrator of the control circuit has a variable resistance r-c circuit, and the resistance is varied by a signal from the temperature sensor so that a pulse for determining the duration of a relatively high increase rate of the actuating pressure at an early stage of the clutch engagement can be prolonged to compensate for a decrease in the friction coefficient of the clutch disc at elevated temperatures.