Interactive SVG Nomogram of 9G-Tronic transmission

Francois Roulet
A B E
B F E
A B F
A B D
A F D
F D E
A E D
C E D
A C D
A B C
PS1 PS2 PS3 PS4




Transmission schematic and shifting table
Description:
This interactive nomogram is a real geometric calculator exactly representing the rotational speeds of the transmission's 3x4 = 12 internal shafts for each of its 9 ratios (+ reverse), grouped according to their 4 permanent coupling on 3 joint ordinates and 5 independent ordinates. These ordinates are positioned on the abscissa in strict accordance with the proportions of the sun gears' teeth numbers relative to those of their rings. Consequently, the output ratios on the 3rd ordinate (carrier of the third planetary gearset) follows closely those of the actual transmission. This advantageous geometric construction sets us free from Willis' famous and tedious formula, because all calculations are exclusively determined by lengths ratios, respectively teeth numbers on the abscissa for the 4 epicyclic ratios, and of rotational speeds on the 3rd ordinate for the 10 gear ratios.

Usage:
Select the gear with the corresponding right button.
(Restore all gears with button)
Adjust the 4 planetary gearsets dimensions with 4 bottom sliders.
(Reset to factory settings with button)
Legend:
A : Brake (blocks s2 sun gear)
B : Brake (blocks r3 ring gear)
C : Brake (blocks c1 carrier gear)
D : Clutch (couples c3+r4)
E : Clutch (couples c1+r2)
F : Clutch (couples s1+c1)