Patent GB-1051741-A (GB)
IPC: F16H63/30
Abstract: 1,051,741. Change-speed and clutch control. REGIE NATIONALE DES USINES RENAULT. Feb. 4, 1964 [Feb. 6. 1963], No. 4747/64. Headings F2D and F2L. [Also in Division H3]  Two solenoids 26, 27 in parallel control a relay switch 25 in the energizing circuit of the main clutch 107 of a motor vehicle preceding the usual change-speed gear, and are actuated by an output-speed responsive governor 7 in such a way as to discriminate between the upshifts and downshifts effected so as to adjust the rapidity of clutch reengagement following a ratio shift. The governor 7 has a contact 5 fast with a spindle 37 turned through an angle dependent on engine speed, and carries a resiliently mounted contact 4. The spindle 37 is connected to the negative side of a battery 101. The remote ends of the two solenoids 26, 27 are connected through the usual ignition switch 102 to the positive side of the battery 101. The solenoid 26 is a pull-in coil and the solenoid 27, arranged in series with a resistor 29, is a holding coil. The relay switch 25 comprises a contact 31 connecting a tap-off coil 133 either to a contact 31, a resistor 148, a relay switch 21 and earth, or when the solenoids 26, 27 are energized, to a contact 33, a resistor 35, a switch 3C and then to earth. Alternatively. the resistors 35, 148 may act in parallel. The coil 133 controls the amplitude of current pulses charging a tank condenser 151, connected across the secondary winding 124 of a transformer 125 having its primary winding 126 in series with the usual induction coil 127 and make-and-break 128 of the vehicle engine, by transmitting current therefrom to earth. The tapping 131 from the condenser 151 to the coil 133 is also connected through a coil 132 to earth. The current pulses applied from the transformer secondary 124 charge the tank condenser 151, and its potential is applied to the base of a transistor 114 which, when it is rendered non-conducting, renders a transistor 105 conducting. The transistor 105 passes current through a relay switch 9 which, when energized, connects the transistor to the coil of the main clutch 107. In the de-energized condition of the relay 9, shown, its switches 11, 14 connect the clutch 107 for direct reverse flow of current from the battery 10, for clutch disengagement. The energizing coil 8 of the relay switch 9 is fed through series-arranged switches 1B, 2B, 3B, each associated with electromagnets or relay controlled electric motors 1A-3A operative to establish three ratios in the controlled gearing, one or other of the switches 1B &c. being opened during a ratio shift by the ratio establishing mechanism. to disengage the main clutch 107. When contacts 18. 19 are opened and contacts 19, 20 are instead closed, the tank condenser 151 is inoperative and a condenser121 is instead fed with current pulses, the condenser 121 discharging rapidly to earth through a rheostat 149. The potential developed across the condenser 121 causes the transistor 114 to go momentarily non-conducting, so that the transistor 105 conducts and supplies a pulse of current to the clutch coil 107. The current fed to the clutch coil 107 is accordingly now dependent upon engine speed up to the engine speed at which the transistor 105 conducts continuously. To put the stationary vehicle into motion. a hand-switch 36 is closed for establishment of first gear. Contacts 5, 6; 1, 4 are closed as shown, so that the solenoids 26, 27 are energized to close the switch 32, 33, and the solenoid 22 closes the contacts 19, 20. The condenser 121 charges and discharges, so that the transistor 105 feeds pulses of current at a speed depending upon engine speed to the clutch coil 107. Increasing engine speed engages the clutch 107. The switch 3C is open, to prevent current passing from the tap-off coil 133 through the closed contacts 32, 33 to earth, so that clutch engagement is relatively fierce. As the vehicle moves off, increasing speed causes the governor 7 to move the contact 5 away from the contact 6, the contacts 1, 4 at first staying closed so that the hold-on relay solenoid 27 keeps the contacts 32, 33 closed. However, the solenoid 22 is de-energized, so that the contacts 18, 19 are closed. The tank condenser 151 now operates and the clutch 107 is maintained engaged. With further increase in vehicle speed, the contact4 of the governor 7 moves away from the contact 1 on to the contact 2; the switch 2B.is opened by the second ratio establishing mechanism 2A, thus de-energizing the relay switch 9 and disengaging the clutch 107. The relay switch 21 is re-energized through its coil 23 and the clutch circuit, rendering the tank condenser 151 again effective, while the relay 25 is is de-energized. The second ratio is accordingly established, and closure of the switch 2B reenergizes the relay 9 for clutch re-engagement. The relay 21 is once more de-energized, since the clutch circuit is no longer connected to the solenoid 23. During re-engagement of the clutch 107, the contacts 31, 32; 18, 19 are closed, so that the coil 133 bleeds-off current from the pulses supplied to the condenser 151, causing the speed-responsive re-engagement of the main clutch to be slower and smoother than when starting. Further increase in speed produces an upshift to third ratio, when the governor contact 5 moves on to the contact 3. Re-engagement of the main clutch 107 is now effected with the switches 31, 33; 3C closed and, since a resistor 35 in this circuit is of higher value than the resistor 148, the clutch reengagement following the 2-3 upshift is more rapid than the engagement following the 1-2 upshift. With decreasing vehicle speed, a 3-2 downshift is effected and the resistor 148 is re-inserted in the clutch circuit, for a cushioned re-engagement of the main clutch. Still further decrease in vehicle speed enforces a 2-1 downshift when the governor contact 4 engages the contact 1. Since the now energized hold-on relay solenoid 27 .alone cannot actuate the switch 31, 32, the two resistors 34, 148 are connected in parallel between the tap-off coil 133 and earth, for a very gradual and smooth re-engagement of the clutch 107. At an even slower speed, the contacts 5, 6 close and the initial conditions re-obtain. As modifications, the resistors 34, 35, 148 may be replaced by condensers &c. to obtain the desired speed of clutch control under varying circumstances, and the relay 25 may act through an electromagnet upon the vehicle engine throttle during ratio shifts.