Automotive plastics: there's more in the pipeline
Aeroquip has been working with DuPont to find new uses for plastics in
engine components. The latest - a sump pipe - is not only lighter, but
cheaper to produce and a lot more reliable than its metal counterpart
Car makers such as Jaguar, Ford and Rover are turning more and more to
plastic replacements for what were traditionally metal components. Among
the latest parts to make the switch is the humble sump-oil pick-up pipe,
which transfers oil from the sump to the point where it is distributed
around the engine. A leading supplier of these components, Aeroquip,
collaborated with DuPont in the development of a range of pick-up pipes,
which have subsequently outperformed metal-based alternatives in terms of
weight-saving, number of parts, ease-of-assembly and warranty claims.
Aeroquip chose a special grade of DuPont's nylon based material, Zytel,
which meets the tough anti-vibration and anti-noise criteria. The two
companies worked on the design of an appropriate manufacturing process
using mould flow software, the optimum filling and heating of the polymer
in the injection moulder being the key to avoiding inbuilt stresses or
cracking. The final product not only offers great flexibility, it can
also withstand constant vibration and can be moulded into complex shapes
to suit any engine sump design.
Unlike its metal counterpart, which may consist of nine parts all welded
together, the Aeroquip pipe comprises just two parts that combine to form
a single pipe shape. The Zytel grade chosen is impervious to oil, can
withstand high engine temperatures and, unlike brazed metal, is not
susceptible to vibration cracking.
Previously, the pipe filter element was crimped and brazed after
assembly, but the plastic version now allows an easy welding of the
filter during assembly. Moreover, depending on the engine configuration,
any number of fixing brackets, inserts and suction cups can be
incorporated into the mould design. Since introducing its Zytel pick-up
pipe range, Aeroquip has produced over three million parts without a
single warranty claim resulting.