GB1427039A - Automatic clutch mechanism - Google Patents

Abstract

1427039 Clutch control AUTOMOBILES M BERLIET 14 Feb 1973 [18 Feb 1972] 7184/73 Heading F2L A clutch control system for the control of a motor vehicle friction clutch II through hydraulic means 24 (or alternatively pneumatic means 25) to close the clutch 11 at a rate proportional to the rate of rotation of the engine, and also dependent on the rate of acceleration of the engine and speed of the vehicle comprises sensors 1, 2 and 3 which detect as electrical frequencies the engine speed, gear-box III input speed and transmission IV speed, respectively. These frequencies are converted to voltages by circuits 4, 5, and 6, respectively. A further circuit 7 evaluates the change in engine I speed, dN/dt where N is engine speed, which is a measure of the intentions of the operator, it being dependent on accelerator VII position and a circuit 11 computes #N, a voltage dependent on the difference in speed between the input and output members of clutch II, which is the difference in the outputs of circuits 4 and 5. The closing of the clutch II for starting the vehicle is by a signal where N 0 is the lowest operational speed of the engine and (Vv), evaluated by circuit 8, is a value computed from that detected by sensor 3, which is proportional to vehicle speed, and is zero for very low speeds but increases above a threshold value of speed to hasten the closing of the clutch II as the vehicle gains speed. The value E, which controls the rate of closing of the clutch, is computed by a circuit 9 and controls the clutch via a correction circuit 10 and a summation circuit 19 which in turn controls an electrovalve 22 or 23 to close the clutch. The signal #N controls a servomotor via electrovalves 12 and 13 to inhibit the action of the driver of the vehicle to reduce #N, and so clutch slip. When the vehicle has attained a speed of V 3 , at which point the starting function is not required, i.e. (Vv)> V 3 as detected by a circuit 15, a switch 16 in circuit 10 moves to remove the control of circuit 9 over the clutch and the clutch is now opened when a gear-change is made, which change causes an inverting device 18 to be switched over to allow a capacitor 26 to be charged by the voltage #N and to supply a signal to the circuit 10 to open the clutch. On completion of the gear-change, the device 18 switches back and the charge on capacitor 26 controls, in conjunction with the vehicle speed Vv, the rate of clutch closure, the latter increasing this rate through a circuit 17 which increases the rate of capacitor discharge, and the former decreasing the rate of closure in proportion to the clutch slip. The value #N also inhibits the action of the vehicle operator via the means 20 during the gear-change.