1. System description of DIWA.3E transmissions

1st gear

(DIWA drive range)

Traction

2nd gear

3rd gear

Road speed

4th gear

Voith Automatic - the principle of power splitting in Voith DIWA transmissions

With fully automatic Voith DIWA transmissions, power transmission in the 1st gear driving range is designed with separation into a mechanical and a hydrodynamic transmission path using a counter-rotating torque converter (see fig. below).

The converter is used for acceleration from standstill and for retardation (braking).

The name "DIWA" combines the elements "DI" for "differential" and "WA" for "Wandler" (the German word for converter) and is thus a symbol of the mechanical and hydrodynamic method of power transmission in the DIWA drive range.

Characteristics of the DIWA torque converter

nhigh torque ratio

nmechanical power transmission right from the start

nstepless ratio change over a wide speed range - in the case of the three-speed variant about 30% of the vehicle top speed vx

nhigh braking capacity without down-shifting

nvibration-damping

nno frictional wear

nonly one hydraulic circuit for both driving and braking

With the 2nd, 3rd and 4th gear, the transmission therefore represents an ideal combination for utilising the benefits accruing from the hydrodynamic and mechanical systems.

The Converter Filling Control

Main difference of the DIWA.3E transmissions compared to the DIWA.3 transmissions is the converter filling control (referred to as CFC). The purpose of the CFC is to improve the activation of the converter brake even when the vehicle is travelling at a high speed in the 4th (or possibly also 3rd) gear.