Patent GB-1399359-A (GB)
Title: Electronic control device for an automatic gear box
IPC: B60K23/00
Filed: 1972-10-23
Abstract: 1399359 Permanent magnet alternators REGIE NATIONALE DES USINES RENAULT and AUTOMOBILES PEUGEOT 23 Oct 1972 [26 Oct 1971] 48816/72 Heading H2A [Also in Division F2] Relates to detail constructional and siting improvements in a speed and load responsive electronic control for a motor vehicle transmission, as well as an improved circuit with surge voltage protection. A torque-varied alternator 3, attached to the casing 7 of the vehicle stepped or stepless ratio transmission, feeds signals to the printed circuit board 27 of the electronic control, and the single external envelope of the alternator and electronic circuit is in three parts viz. (1) an insulating moulding 6 having two integral side-by-side compartments, one for the alternator, the other 33 for the circuit; (2) a member 3a, 3b, adhesively secured to the moulding 6, extending into the casing 7 of the vehicle transmission and closing the alternator compartment; and (3) a stamped sheet metal cover 29 closing the circuit compartment. The alternator comprises a shaft 1 driven by the output shaft of the transmission through a coupling dog 2, or a press-fitted polyamide splined coupling sleeve, or directly by spiral gears, and the shaft 1 carries at its upper end a multi-pole permanent magnet 11 rotating in an adjustable pole structure comprising two concentric stationary sleeves 12, 13 welded or adhered together, and having interfitting polepieces 12a, 13a extending in opposite directions half way along their lengths, and a third inner sleeve 15 carrying polepieces 15a extending between the poles 12a, 13a and turnable about the shaft axis by a control 14 linked to the engine throttle, whereby the analogue voltage output of the alternator responds to output speed and engine load. Three leads 25 from the stationary winding 18 of the alternator, stationed in thermosetting tapes (Fig. 2, not shown) pass through an opening in a plastics cover 6 for connection to the circuit board 27, which carries power transistor such as 28 held by springs 30 in recesses in a heatradiating metal cover-plate 29, and output leads for energizing shift-valve solenoids are led out at an opening 37. In Figs. 5-9, not shown, the circuit board (38) is arranged vertically and has depending conductors passing through sealed openings into the transmission casing where they are engaged by spring contact blades (49). Electronic circuit, Fig. 13.-Outputs 19a, 19b, 19c of the alternator winding 18 lead through Zener diodes 74, 75 and filtering capacitors 76, 77 to the non-inverting input of an operational amplifier 82, the inverting input 83 of which is a voltage from a divider 85, 86, stabilized by a Zener diode 89, and driven at 87 through a resistor 90 from battery positive 91. The stabilized voltage 87 also feeds at 92 the amplifier so that both the voltages 83 and 92 of the latter have the same origin and are simultaneously regulated against temporary overvoltages in the battery line. The output of the amplifier 82 is connected to the base of a PNP transistor 93 in circuit with the winding 72 of a shift-valve solenoid of the transmission, and also to a limiting Zener diode 94, in parallel with a NPN output transistor 95 of the amplifier. When the alternator winding 18 causes the amplifier 82 to switch off the transistor 93 for de-energizing the shift-valve solenoid 72, the inductance of that solenoid applies a positive voltage to the emitter of 93 relative to its base, so that 93 remains conductive as long as the inductive energy remains in the solenoid 72. The inductive voltage exceeds the voltage of the supply and also that of the Zener diode 94, which applies the increased voltage to the base of the transistor 93, thus increasing its conductivity and so reducing the inductive voltage of the solenoid 72. This protects the circuit against inductive overvoltage. External overvoltage on the battery line 91 reaches the emitter and base of the transistor 93 through the shift-valve solenoid 72 and a resistor 97 respectively, providing further protection Temperature compensation is provided by offsetting the negative temperature coefficient of the diodes 74, 75 against a positive coefficient for the diode 89. An identical circuit controls energization of a second shift-valve solenoid 73, and if desired also a third.