Volkswagen Direct Shift Gearbox
Alan impressed us all with his demonstration model of Volkswagen DSG (Direct Shift Gearbox): a 6-speed and reverse, computer controlled dual clutch transmission.
It features an over-centre spring-loaded clutch switching mechanism, a dual clutch using large axle (hollow) and tri-flat parts to split the drive into the constant mesh gearbox, 50-tooth contrate gear synchronizer assemblies and series connected inter-axle and front axle differentials, bevel gear rear axle drive output.
Gear changing and clutch switching is effected by five hobby servos operated from a servo driver board (printed circuit).
The dual clutch principle is to serve the odd numbered gears with one clutch and the even numbered gears served by the second clutch, facilitating rapid and smooth gear changing. In the DSG, clutch (1) serves 1st, 3rd, 5th & reverse; clutch (2): 2nd, 4th, & 6th — this pattern is reproduced in the model.
The model demonstrates the DSG gear changing strategies in pre-selecting the subsequent gear ratio then en-gaging it by switching clutches.
The servo driver board receives its commands from either of two forms of PC software. One is the driver board manufacturer’s scripted program; the other is by QBASIC programming code.
The latter enables the gear engagement and pre-selection events to be displayed on the computer screen. Either program enables any sequence of up-shifts, down-shifts and timing of in-gear/neutral events.
Read an in-depth article about this model.