Control blocking distributor gearbox shift senses speed downstream of clutch

摘要

An engine (1) drives a motor vehicle by way of a clutch (2), a main gearbox (3) and a synchronized distributor gearbox (6). Shifting into cross-country speed is initiated by operating a preselection switch (31) and the clutch pedal. The control device (25) calculates an advanced shifting point from the rotating speed drop of a transmission input shaft (4) and an anticipated shifting time. By this, shifting is cleared before the rotating speed at which the engine overspeed is reached. This enables an early and easy downshift into cross-country speed. The control device inputs one preferably additionally a speed engaged signal (sS), and an oil temperature signal (sT). There may be a warning lamp (32) and/or an audible warning (33) operating when a change is requested and the speed is low.