Overriding ratio matching feature in power shift transmissions

摘要

A power shift transmission (10) is disclosed having a ratio matching feature whereby the disengagement of the transmission (10) by moving the gearshift lever (6) to the neutral position or by depressing the clutch pedal (3) initiates a routine in the microprocessor (1) controlling the operation of the transmission (10) to calculate the ratio of the rotation of the input and output shafts (15, 20) of the transmission (10) and select the gear most closely matching the calculated ratio. The ratio matching routine can be manually overridden by signalling a gear change with the gearshift lever (6). The override feature for the ratio matching routine can be permanent for each disengagement of the transmission (10) or temporary for the running of a timer (446) for a predetermined length of time.