There are three routes open to achieving these targets: smaller and more efficient engines, alternative drive trains, and innovative lightweight construction concepts that reduce weight and fuel consumption too. Whilst the potential to achieve more efficient engines has been all but exhausted, light weighting has become a high priority in the automotive industry. A 100 kilogram reduction in weight reduces fuel consumption by, on average, half a litre per 100 kilometres and saves somewhere between 8 and 10 grams of CO2 per kilometre.
This light weighting concept is not just useful for conventional combustion engines, but it is also highly sought after in the construction of electric vehicles. The motivation here is obviously different. The reduction in vehicle weight does not lead to a reduction in CO2 emissions, but rather to an increase in vehicle performance and operating range. Plastic has become increasingly more important in automotive construction over the last decade. Today, an average of up to a quarter of all the components on a modern car are made from this material.
A new technology with great potential in the area of light weighting are compounds based on recycled carbon fibre. WIPAG Deutschland GmbH have developed a technology and product ranges called WIC PP and WIC PA, which replace heavy highly concentrated glass fibre PA compounds with relatively lighter PP and PA rCF compounds. WIPAG is a company, acquired by ALBIS Plastic, that specializes in the processing and production of carbon fibre based compounds that can be injection-molded and are made from CF production residues from the automotive and aviation industries in a closed-loop system.
The weight reduction is huge. Switching material can save up to 30 percent for comparable characteristics and costs. At first glance, the price per kilo seems higher than the PA compounds, but the PP carbon fibre components are more cost effective due to their lower density.
A good example of this is the sample calculation that the Albis team did for a fuel cap hinge arm.
For the review a polyamide 6 with a 50 percent glass fibre content was replaced by a polypropylene strengthened with 30 percent recycled carbon fibre. The resultant significant weight reduction, which was greater than 30 percent, came from the difference in density between the glass fibre compound, with 1.58g per cm3, and the carbon fibre alternative, with 1.05g per cm3. "Looking at the volume price calculation of the compound, we saw a reduction in the material costs for the component of some five to ten percent. The apparent additional cost of the carbon fibre compound in Euro/kg disappeared when we looked at the litre price in Euro/l," explained Bernd Sparenberg, Vice President Technical Compounds at ALBIS Plastic. "The end customer buys based on volume and not on the weight of a component."
