Page 228 - Automotive Engineering Powertrain Chassis System and Vehicle Body

Fig. 8.1-45 VW Transporter, a light truck which could be used either as an eight-seater bus or for transporting goods, and which has
the optimal axle load distribution of 50%/50% in almost all loading conditions. The double wishbone suspension at the front, the
semi-trailing link rear axle and the rack and pinion steering, which is operated via an additional gear set in front, can be seen clearly.
To achieve a flat load floor throughout, VW changed the Transporter to front-wheel drive in 1990.

Fig. 8.1-46 The Porsche Boxster (1996) has a water-cooled engine which is longitudinally installed in front of the rear axle. The front
axle is designed as a spring strut-type axle. The transverse link is arranged almost in extension of the wheel axle; it is connected to the
longitudinal link by a strut bush which is soft for reasons of comfort. This open design and link geometry make it possible to combine
a high level of driving precision, a result of rigid wheel control, with riding comfort, owing to the longitudinal elasticity of the axle. At

a camber angle of 8 , good straight running results from the large castor displacement of 41 mm. The kingpin offset is 7 mm and the
disturbing force lever arm is 83 mm. The pitch centre of the front axle was located near to the road to achieve kinematic wheel recession
of the axle, which is important for riding comfort, with the result that braking-torque compensation is only 10%.
The rear axle is also a spring strut-type axle in an open link design; the wheel carrier, hub and bushes as well as the transverse link
are the same as those found on the front axle. The open design makes it possible to have an inwardly inclined elastokinematic axis of
rotation, so that a stabilizing toe-in position of the rear wheels is produced during braking. The axle can also be designed to
understeer when subject to lateral forces.
The main disadvantages of the mid-engine design are apparent from the boot space: only 130 I are available at both the front and back.