Page 248 - Automotive Engineering Powertrain Chassis System and Vehicle Body

CH AP TER 8 .1 Types of suspension and drive

Fig. 8.1-79 The torque coming from the engine is apportioned by the Planet Wheel-Centric Differential 1 in such one, to the rear
cardan shaft 2 (64%) and to the front one 3 (36%). The offset to this shaft is bridged-over by the inserted tooth type chain 4. The
adaptation of the distribution of driving power is taken over the multiple-disk clutch 5, which is driven (controlled) by the
electromagnet. Power Divider A110 of the Fa. ZF (Zahnradfabrik Friedrichshafen).

between the cargo area and the rear axle. Fig. 8.1-70 electronically controlled multi-disc clutches (Haldex
shows the design details: clutch, Fig. 8.1-73);
a visco clutch in the propshaft power train, which se-
a central power take-off gear with manual selection lects the initially undriven axle depending on the tyre
for the front axle, plus a larger ratio off-road gear, slip (Figs. 8.1-72, 8.1-74 and 8.1-75).
which can be engaged if desired;
three propshafts; Here too, the front-wheel-drive passenger car is suitable
complex accommodation of the drive joints if there as a basic vehicle. In 1979, Audi was the first company to
is a rigid front axle (Fig. 8.1-3). bring out a car with permanent four-wheel drive, the
Quattro, and today vehicles with this type of drive are
8.1.7.4 Permanent four-wheel available throughout the entire Audi range. On a longi-
drive; basic passenger car with tudinally mounted engine, a Torsen centre differential
distributes the moment according to the traction re-
front-wheel drive quirement (Fig. 8.1-71). The four-wheel drive increases
the weight by around 100 kg.
All four wheels are constantly driven; this can be VW used a visco clutch in the power train (without
achieved between the front and rear axle with different centre differential) for the first time on the Transporter
design principles:
(Fig. 8.1-74) and then subsequently used it in the Golf
a bevel centre differential with or without manual syncro. The clutch has the advantage of the engine
lock selection; moment distribution being dependent on the tyre slip.
a Torsen centre differential with moment If the slip on the front wheels, which are otherwise
distribution, based on the traction requirement driven at the higher moment, increases on a wet or
(Fig. 8.1-71); frozen surface or off-road, more drive is applied to the
a planet gear central differential with fixed moment rear wheels. No action on the part of the driver is either
distribution and additional visco clutch, which auto- necessary or possible. The transverse engine makes
matically takes over the locking function when a dif- a bevel gear in front of the split prop shaft necessary.
ference in the number of revolutions occurs or The visco clutch sits in the rear differential casing and
a magnetic clutch (which is electronically controlled, there is also an overrunning clutch, which ensures that
Fig. 8.1-79); the rear wheels are automatically disengaged from the

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