GB1053049A - - Google Patents

Abstract

1,053,049. Change speed control. REGIE NATIONALE DES USINES RENAULT. March 5, 1964 [March 7, 1963], No. 9445/64. Heading F2D. [Also in Division H3] In a change speed control for a motor vehicle wherein ratio shift is effected automatically by an output speed responsive control 24 which also disengages the main clutch 3 during shift, the engine speed is reduced during the shift interval by retarding the ignition. In Fig. 1 a contact breaker 8 is connected to the core 10 of an electromagnet 11 so that when the latter is energized the angular position of the contact breaker 8 is adjusted to retard ignition. During ratio shift the control 24 opens a switch 29 to deenergize a relay 13 whereupon contacts 14, 17 move to the position shown in which the clutch winding 4 is de-energized and the contacts 16, 17 complete the circuit to the ignition retarding electromagnet 11. Movement of the electromagnet 11 may be damped by a dashpot. In Fig. 2 (not shown), energization of the electromagnet 11 additionally closes an auxiliary throttle valve. Movement of the contact breaker may be effected by a fluid pressure or suction motor controlled by an electromagnetic valve. In Fig. 3 an auxiliary contact breaker 36 is provided and on de-energization of the relay 13 during gear shift contacts 14, 38 move to the position shown in which the former 14 deenergizes the clutch winding 4 whilst the latter 38 breaks the circuit to the main contact breaker 8 and completes the circuit to the auxiliary contact breaker 36 which retards the ignition. If the auxiliary contact breaker 36 opens before the main contact breaker 8 closes the line 47 may be permanently connected to the line 21 and the contact 40 omitted. In a transistorized ignition circuit, Fig. 6, the ignition timing is governed by an engine driven slotted disc 50 which moves past a magnetic core 48 to produce pulses in a coil 51. Each positive pulse acts through a condenser 52 to apply a negative pulse to the base 53 of a transistor 54 which together with a transistor 55 constitutes a monostable multivibrator. Negative pulses in the coil 51 are short circuited by a diode 56. Each pulse renders the transistor 54 conducting and thereby transmits a pulse through the condenser 64 to cut off the transistor 55 whereupon the voltage at its collector 59 rises. This voltage variation at the collector 59 is applied through a relay contact 38 and a differentiating condenser 73 to the control electrode 70 of a solid thyratron 69 which becomes conducting and permits a condenser 71 to discharge through the primary 7 of the ignition coil. The condenser 71 is recharged through a resistor 72. During a gear shift the relay coil 13 is de-energized to change contacts 17, 38, the former of which de-energizes the clutch winding 4 whilst the latter 38 disconnects the condenser 73 from the collector 59 of transistor 55 and connects it to the collector 61 of transistor 54. Thus during ratio shift the thyratron 69 is responsive to voltage rise produced at the collector 61 when the transistor 54 cuts off. This voltage rise is subject to a time lag produced by a resistor 67 and condenser 64 and therefor the ignition is retarded. The resistor 67 may be replaced by a transistor operated as a variable resistor and having its base connected to a resistor and condenser circuit having a high time constant. This condenser being charged or discharged through an additional contact in the relay 13 to increase or decrease ignition retard. The control contact 70 of the thyratron 69 may be permanently connected through the differentiating condenser 73 to the collector 61 of transistor 54 and the ignition retarded by varying the duration of the pulse.