Automotive industry weight reduction

FIGURE 37.3 Weight reduction methodology in the automotive industry. (From Haraguchi, T., Nippon Gomu Kyokaishi, 79, 103, 2006.)... 

With a density of 1.7 g/cm for magnesium and 2.7 g/cm for aluminum, both materials are considered as light metals. That is why they are preferred construction materials for the automotive as well as aerospace industry where weight reduction is an important issue. The alloys of both metals are in general known for their excellent machinability. 

The nonwoven fabrics are very versatile materials and are being extensively used for gas and liquid filter appUcations, including pharmaceuticals, food and drink, vacuum cleaners, and industrial applications. Within the automotive industry, there are performance considerations, including pollution reduction and bacterial protection combined with lower weight and the environmental impact. These requirements can be fulfilled with the use of a range of versatile nonwoven production processes. 

Various automotive parts made of natural fiber composites are shown in Table 22.16. The use of plant fiber (sisal/flax/hemp etc.) based automobile parts such as trim parts, various panels, shelves, and brake shoes are attracting automobile industries worldwide because of its weight reduction, energy and cost saving. Conservative estimates indicate that about 6,000 TPA plant fiber-based composite parts can find their way into passenger cars and multi-utility vehicles [17]. 

Metal foams are a new class of materials that may revolutionize the car industry. Automotive makers know that one key to making cars that are fuel efficient is to decrease weight. Up till now, that weight reduction meant higher cost (in materials like titanium and aluminum) and problems in crash testing (since light vehicles don t absorb energy well). 

Development and use of additives to improve sound insulation properties of plastics compounds (especially required by the automotive industry) has been a strong theme of recent development. In the past, insulation theory has taken it that the most significant factor is mass, and by increasing it, insulation can be improved. This has led to use of heavy loadings of heavy fillers, such as barytes, but it goes diametrically against the other requirement of the automotive industry, reduction in weight. 

Polymers, and particularly polyesters, are widely used in the automotive industry. Nowadays an average car contains over 100 kg of plastics without plastics, the car would be 200-300 kg heavier, which is equivalent to an extra 0.5-0.9 litres of fuel consumption per 100 km. More than 1,000 different car parts can be made of polymers, but the types of polymers are limited, with fewer than 15 different polymers used. The Chevy Volt, a prototype of an electric car, was introduced by General Motors in 2009 and consists of a variety of polymers. Tests have shown that the car could offer fuel savings of up to 2000 litres a year. Moreover, the elements made from special polymer composites had better resistance against environmental and mechanical factors [26-30]. In the aerospace industry, Kazmerski et al. introduced a new use for reinforced composites in aircraft. It was demonstrated that 6000 rivets and 300 metallic parts of the Airbus A 340 aircraft could be replaeed by 100 composite elements, for example, in the turbine wings, aehieving a two-ton weight reduction [7, 31]. 

An important and closely related application technology is in composite fibre/plas-tics stmcmres, many of which incorporate nonwovens. These composite technologies are fundamentally well-suited to the needs of the important growth areas of lightweight constmction. Component weight reduction is a driver in the automotive, aerospace, boatbuilding, and mechanical engineering industries. 

It is possible that PP fibers will further replace polyamides and polyesters in automotive applications, since recent developments have shown that it is feasible to stabilize the PP fiber to levels far exceeding those for PA and PES ones. The specific gravity advantage of PP is particularly useful in the manufacture of car carpets its excellent cover-to-weight ratio was attractive to the automotive industry, in which reduction of weight currently equates with savings in fuel. 

The light weight of polyolehns makes for more fuel efficient vehicles. It is estimated that every 10% reduction in vehicle weight results in a 5-7% reduction in fiiel usage. Current economic and environmental concerns make the creation of more fuel efficient cars a top priority in the automotive industry. Some other advantages of polypropylene used in automotive industry include ... 

Most TPEs have a lower density than a conventional vulcanized rubber compound. They are sometimes preferred in weight-reduction programs, as in the automotive industry, further, the material in a rubber article is usually purchased on a weight basis but used on a volume basis, thus providing a material cost benefit with a TPE. 

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