| 摘要 |
1,085,544. Transistor switching circuits. REGIE NATIONALE DES USINES RENAULT. Dec. 10, 1964 [Dec. 31, 1963], No. 50421/64. Heading H3T. [Also in Division F2] An electronic gear-change control comprises a two-state circuit which produces downward gear change at a lower engine speed than the upward gear change. Output of an alternator 1 is applied to a potentiometer 11, the rotor 2 being driven from the gear-box output shaft and being positioned relative to stator 4 by the accelerator pedal 5 so that the output voltage is a function of vehicle speed and accelerator pedal position. Slider 17 is connected to transistor 19 controlling a Schmitt trigger 22, 23, controlling energization of a winding 30 which changes the gear upwards when de-energized. When the vehicle is moving in bottom gear the transistors 19, 22 are non-conductive and transistor 23 is conductive to energize winding 30. Current flows from point P towards point N to provide across diode 32 a bias for the emitter additional to that provided by Zener diode 15. When the potential at slider 17 exceeds the emitter bias transistor 19 and then transistor 22 become conductive to block transistor 23, winding 30 becoming de-energized and the gear changes up. The potential at P drops, diode 31 becomes non-conducting and the potential at N becomes about equal to that at slider 35 resulting in the base-emitter conductive threshold of transistor 19 being lowered. Therefore the change down, which occurs when transistor 19 becomes non-conductive, will be at a lower engine speed than for the upward change. The gap between the engine speeds for up and down change is adjusted by moving slider 35 while movement of slider 17 sets the condition for upward movement. The engine speed at which change down takes place can be increased by pressing accelerator pedal 5 to open switch 34, the potential at slider 35 tends to become equal to that at M and change down occurs at approximately equal engine speed to change up. A circuit for controlling several gear ratios, e.g. in an epicyclic gear gox, is given in Fig. 2, not shown. |
