Page 251 - Automotive Engineering Powertrain Chassis System and Vehicle Body

Types of suspension and drive CHAPTER 8.1

Motor Reduction Drive Four-wheel drive Middle Front axle Rear axle Example
position drive on differential differential differential
switched slip perm. locks via
by dependent by locking brake locking brake
longit. 2.05:1 rear sprag-clutch man. N/A n n n n Opel Frontera
longit. 1.425:1 rear sprag-clutch man. N/A n n multi-disc n Mitsubishi Pajero
clutch
longit. 2.15:1 rear sprag-clutch man. N/A n n n n Suzuki Jimny Cross
Country
longit. 2.43:1 rear sprag-clutch man. N/A n n multi-disc n Chevrolet Blazer
clutch
longit. 2.48:1 rear multi-disc. electron. N/A n n multi-disc n Ford Explorer
clutch
transv. front multi-disc electron. N/A n n nn n Honda CR-V
longit. 2.72:1 rear visco N/A n n multi-disc n Jeep Grand Cherokee
clutch
transv. front visco N/A n n n n Chrysler Voyager 4WD
transv. front visco N/A n y n y Land Rover
Freelander Discovery
longit. rear visco N/A n y n y Porsche Carrera 4
transv. front visco N/A n y multi-disc n Volvo V70 R AWD
clutch
transv. front visco N/A n y multi-disc n VW Multivan Synchro
clutch
transv. front Haldex N/A n y n n Audi TT Quattro,
multi-disc Golf 4motion
longit. f + r longit. claw clutch n n n n Daihatsu Terios
diff.
longit. 2.64:1 f + r longit. N/A n y n y Mercedes-Benz M series
diff.
longit. y f + r longit. y y n y n Mercedes-Benz G series
diff.
longit. f + r longit. N/A n y n y Mercedes-Benz E series
diff.
longit. f + r longit. N/A n y n y BMW Sports Activity
diff. Vehicle (SAV, E53)
longit. 1.21:1 f + r longit. N/A n y n y Land Rover Discovery
diff.
y f + r longit. visco + man. Toyoto LandCruiser
diff.
longit. 1.93:1 f + r longit. visco + man. n n sprag-clutch n Mitsubishi Pajero
diff.
longit. 1.20:1 f + r longit. visco lock n n n n Subaru Legacy Outback
1
diff.
longit. 1.45:1 f + r longit. visco lock n n n n Subaru Forester
diff.
. transv f + r Torsen self-locking n y n y Audi A4/A6 Quattro,
diff. VW Passat Synchro
transv f + r Torsen self-locking n y n y Audi A4/A6 Quattro,
.
diff. VW Passat Synchro
Fig. 8.1-83 Different kinds of four-wheel drive.

they allow maximum traction without loss of driving central differential situated on the gearbox outlet and
stability (Fig. 8.1-66). a front axle gear integrated into the engine-oil pan. The
The locks are open during normal driving. By including the (fixed) driving torque distribution is 35%:65%. Instead
front axle differential, they make it possible to equalize of traditional differential locks, the wheel brakes are
the number of revolutions between all wheels, so tight activated on the spinning wheels as in off-road vehicles of
bends can be negotiated without stress in the power train the M class (Figs. 8.1-81 and 8.1-82). This system per-
and parking presents no problems. If the car is moved with mits maximum flexibility, its effect not only corresponds
locked differentials and the driver is forced to apply the to differential locks on front and rear axles as well as on
brakes, the locks are released in a fraction of a second. The the central differential, but also makes it possible for
system is therefore fully ABS compatible. other functions such as ABS and electronic yaw control
In its four-wheel drive vehicles of the E class (ESP) to be integrated without any problem. Design
(Fig. 8.1-78), Mercedes-Benz uses a transfer gear with complexity – and thus cost – is considerable.

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