Self-Study Program

31
1st gear i = 4.148
Description of gear/torque curve
367_023
Shift elements: clutch K1 - freewheel F
The turbine shaft drives ring gear H1 of the
primary planetary gear set. Ring gear H1 drives
the planetary gears P1, which revolve around the
stationary sun gear S1.
Planet carrier PT1 is driven in this way.
Clutch K1 connects PT1 to sun gear S3 and thus
introduces torque into the secondary planetary
gear set.
Freewheel F locks planet carrier PT2.
Torque is transmitted from sun gear S3 to the
short planetary gears P3 and , in turn, to the
long planetary gears P2.
The torque multiplied by PT2 is transmitted to ring
gear H2, which is connected to the gearbox output
shaft.
Since 1st gear is implemented via freewheel F, no
power is transmitted when coasting in 1st gear.
When coasting, the wheels drive the engine.
Freewheel F rotates counter to its locking direction
(in the freewheeling direction), with the result that
the engine braking effect cannot be used.
To be able to utilise the engine braking effect in
1st gear, tiptronic mode must be selected.
See description of 1st gear in tiptronic mode
overleaf.
Torque curve/power flow
Parts are stationary or are held
stationary
Parts rotate without being involved
in the flow of power
Reference
You will find notes on the schematic diagram
on page 18, 22 and in SSP 283 on page 55.