Plastic camshaft will reduce weight and CO2 emissions

Fraunhofer Institute for Chemical Technology ICT, in collaboration with their partners, has succeeded in manufacturing a camshaft module from fibre-reinforced thermoset polymers. This lightweight design element will help lower engine weight and reduces assembly costs.

• Lightweight design
• High-strength fibre-reinforced thermoset polymers
• Materials withstand high temperatures and chemical stresses
• Near-net-shape casting - reduced production costs
• NVH advantage over aluminium

Camshafts ensure that the charge-cycle valves in internal combustion engines are opened and closed reliably and precisely. These valves are located in the camshaft module, the standard material for which is still aluminium. But automotive manufacturers and suppliers are putting great effort into producing powertrains and their components in lightweight design. Weight reduction is one of the most effective methods for reducing CO2 emissions. Researchers at Fraunhofer ICT in Pfinztal are supporting the automotive industry in its efforts with a newly developed camshaft module made of thermosetting composite materials. This lightweight camshaft module was realised in cooperation with the MAHLE Group and associated partners Daimler AG, SBHPP/Vyncolit NV and Georges Pernoud. The German Federal Ministry for Economic Affairs and Energy (BMWi) has been funding the project.

When it comes to the choice of the right polymer, the project partners opted for highstrength, fibre-reinforced thermoset polymers, as they are well able to withstand high temperatures and mechanical and chemical stresses such as those caused by synthetic motor oils and coolants, for instance. 'We contribute the know-how regarding how to design the component geometries to suit the material and the process so that they satisfy all requirements,' says Thomas Sorg, a researcher at Fraunhofer ICT. 'The camshaft module is located in the cylinder head, so normally in the upper installation space of the powertrain. Here, it makes particular sense to reduce weight, since doing so also contributes to lowering the vehicle's centre of gravity.'

Castings made from aluminium require extensive reworking after casting, resulting in high costs. Fibre-reinforced thermoset polymers allows a near-net-shape manufacturing, thus requiring comparatively little reworking and which again leads to reduced production cost. Also, at up to 500,000 units, the service life of thermoset polymer injection moulds is significantly higher than that of aluminium high-pressure die cast to manufacture.

Another advantage is that as automotive manufacturers are eager to minimise noise emissions. Rattling cars are not only annoying, they are also a clear competitive disadvantage, so noise, vibration and harshness (NVH) characteristics are high up on the list of factors used to assess vehicle quality. Polymers have good damping characteristics. 'This makes it very easy to optimise the acoustic performance of the camshaft module.' says Sorg.

Source: Fraunhofer