Page 51 - BPW axles with air suspension Series O SL AL

Single and dual-circuit air suspension installation 10.2

BPW air suspension systems possess a high roll stability for low transverse inclination when cornering,
leading to excellent road safety. This high roll stability characteristic is achieved because the body is
supported when cornering not only by the air bags but also by the stabilisation effect of the axle beam
to trailing arm connection.

The type of air suspension installation has a significant influence on the roll stability characteristics:

D Duuaall--cciirrccuuiitt vveerrssiioonn wwiitthh ttrraannssvveerrssee tthhrroottttllee::
The air bags on the right and left sides of the vehicle
are pneumatically separated and are only connected
together by a transverse throttle in the air suspension
432 121 135 1 3
valve. During cornering, the air can only equalise itself l, 200, l m, 20
41
g, h, 303
slowly between the two sides of the vehicle. As a result, Dual-circuit BPW air
42
i, k, 304
the air bags additionally assist in supporting the rolling suspension installation with
432 i, k
motion of the vehicle body. 039 transverse throttle
l, 200, l l, 200, l 3
S Siinnggllee--cciirrccuuiitt vveerrssiioonn wwiitthhoouutt ttr raannssvveerrssee tthhrroottttllee:: c, d, 440 c, d, 301
150
0, l 004
154
The air bags on the left and right-hand sides of the
vehicle are pneumatically connected. There is no trans- c, d, 320 l, 200, l
361
361
verse throttle. During cornering, the air can equalise 186 3
itself more quickly between the two sides of the vehi-
cle. This means the rolling motion is not supported by
the air bags.
The roll stability and, therefore, road safety is consequently reduced in comparison with a dual-circuit air
installation. As well as the reduction in road safety, the mechanical loads in the air suspension unit are
also distributed differently. Since there is no roll stabilisation of the air bags, the axle and trailing arm com-
bination has to undertake this portion of the stabilisation as well.

The use of single-circuit air suspension installations can lead to damage to the vehicle as a result of the
higher loads. For this reason, BPW cannot offer aannyy wwaarrrraannttyy for chassis and ssuussppeennssiioonn ddaammaaggee result-
ing from this effect.

To achieve optimum function and the greatest possible road safety, in particular in critical situations, we
expressly recommend using dual-circuit air suspension installations with a transverse throttle incorporated
in the levelling valve.

Lifting axles are the only exception to this recommendation. In this case, it is permitted for at most one
lifting axle in a three or four-axle unit to be installed with one circuit.

BPW-EA-Luft 1023701e 51