Patent GB-1514371-A (GB)
Title: Clutch actuating apparatus
IPC: B60W30/18
Filed: 1976-03-03
Abstract: 1514371 Clutch control NISSAN MOTOR CO Ltd 3 March 1976 08574/76 Heading F2L A clutch control for a motor vehicle comprises a valve 64 which on closure of a touch-sensitive gear shift lever switch 88 and a switch 90 which is closed when an accelerator pedal 24 is released connects a clutch disengaging servomotor 138 to a vacuum chamber 38 for clutch disengagement and on opening one of the switches 88, 90 connects the servomotor 138 to atmosphere through valves 92, 94 which control the rate of clutch re-engagement in response to vehicle speed and accelerator pedal position. The valve 92 is biased by a spring 114 to an open position and is closed by a solenoid operated plunger 112 when vehicle speed and accelerator pedal position switches 118, 120 are closed. The switch 118 is closed when the vehicle speed is below a predetermined value and the switch 120 is closed when the accelerator pedal depression is less than a predetermined value. A tapered needle 124 of the valve 94 is biased by a spring 130 to close the valve 94 and is progressively moved to open the valve on depression of the accelerator pedal 24 which acts on the tapered needle 24 through a cable 132. An additional solenoid operated air inlet valve 168 may be provided to effect rapid take-up of free movement in the clutch control linkage during clutch re-engagement. The valve 168 is normally biased by a spring 170 to a closed position and is opened by a solenoid operated plnuger 178 when a switch 182 is closed. The switch 182 is closed when the servomotor diaphragm 140 approaches the clutch fully disengaged position. Operation.-With the accelerator pedal 24 released and the switch 90 closed actuation of the gear shift lever 22 closes the switch 88 to energize a solenoid 76 which moves a plunger 80 left to change over the valve 64 and connect the servomotor 138 to the vacuum chamber 38 for clutch disengagement. When the clutch approaches full disengagement the switch 182 is closed to energize a solenoid 174 which moves the plunger 178 down to open the air valve 168. When the gear shift is completed the solenoid 76 is de-energized and the valve 64 changes back to the position shown whereupon air is supplied through the valve 168 to the servomotor 138 to effect rapid take-up of free movement in the clutch linkage. Thereafter the switch 182 opens to de-energize the solenoid 174 and close the valve 168. Further clutch engaging movement being controlled by the valves 92, 94. If the vehicle speed is below the predetermined value and the accelerator pedal 24 released both valves 92, 94 are closed to prevent further clutch engaging movement. As the accelerator pedal 24 is depressed the valve 94 is opened to provide a progressively increasing air supply to the servomotor 138 for controlled engagement. If the accelerator pedal 24 is depressed beyond the predetermined amount the switch 120 opens to de-energize the solenoid 106 and open the valve 92 in addition for increased rate of clutch engagement. If, after the take-up of free movement in the clutch linkage, the vehicle speed is above the predetermined value the valve 92 is open and clutch re-engagement progresses at a predetermined rate. Depression of the accelerator pedal 24 opens the valve 94 in addition to increase the rate of clutch engagement. If, during ratio shift, the accelerator pedal 24 is depressed the switch 90 opens to effect clutch re-engagement and thus prevent overspeed of the engine. In Fig. 1 (not shown) the additional air valve 168 and the switch 182 are omitted.