The huge growing world car ownership is great influencing people’s work and life, but resulting a series of problems such as energy shortage, environment pollution are also increasingly prominent. Light-weight, energy saving, environmental protection, safety, comfort and low cost become the target of each car manufacturer, especially in energy saving and environmental protection, which is the major problem for the sustainable development of human relationship, energy conservation and emissions reduction has become an urgent problem in the automotive industry.
Light-weight of automobile, which means on the premise of guarantee vehicle performance is not affected, auto-manufacturers should be targeted to reduce automobile weight, to ensure the safety and comfort, and meanwhile should not improve the cost.
From the life cycle of the automobile products, a fuel consumption cost is the main part of the vehicle life cycle cost, which occupies for 71% of the cycle costs. Automobile users are keen to reduce fuel consumption cost to save the running cost later. Due to the weight of the automotive affects the rolling resistance, climbing resistance and acceleration resistance, so it has a very close relationship with fuel consumption.
The main methods of reducing the fuel consumption according to analysis are: Light-weight occupies for 50%, improving the efficiency of engine for 20%, reducing the driving resistance for 30%, and one of the most effective method is to light automotive weight. The aluminum association report pointed out that the fuel consumption will be reduced by 6% ~ 8% when 10% reduction in automotive weight.
Therefore, lightweight is a problem that must be taken into consideration in the design. Auto lightweight can not only reduce all kinds of driving resistance, reduce fuel consumption, but also to improve vehicle steering, acceleration, braking and emission performance. China’s development and reform commission (NDRC) required the average new passenger car fuel consumption to reduce by 15%, it will be hard to achieve the target if no light-weight.
It should be noted that not only required vehicles to light weight can improve fuel economy, improve the quality of cargo, commercial vehicles and passenger cars also has the obvious effect. Meanwhile, with the enlargement of the scope of charge weight and rising oil prices, the trucker have to carry more, and oil consumption is higher and higher, each big trucks enterprises are concentrated on lightweight development.
There are many approaches to light weighting, but the most directly and effective method is application of new light-weight materials which has small density and high intensity, such as aluminum, magnesium alloy, plastic polymer materials, ceramic materials, etc.; Using the same density, elastic modulus and process performance good cross section thickness thinner high strength steel; Using a new material processing technology of lightweight structure material, such as continuous extrusion variable cross-section profiles, metal matrix composites, such as laser welding plate.
Among them, the high strength aluminum alloy series have high degree of commercialization. Take the Audi Company for example, who manufactured the whole aluminum A8 sedans, which adopted aluminum alloy extrusion as car frame, the weight had reduced by 35%, meanwhile the torsional strength had increased by 50%.
Aluminum alloy wheel, suspension parts, body, heat exchangers, etc. Aluminum would instead of traditional steel manufacturing auto parts, which could make the vehicle weight reduce 30% to 50%. In the schedule of PNGV, for there are several kinds of schemes of aluminum car body structure design would put into batch production that could reduce the weight of 55%.
General motors adopts aluminium parts in Cadillac suspension system, also increased the size of aluminum instead of cast iron in manufacture of suspension system for knuckle.
Ford adopts aluminium brake flap, the weight is only 2.27 kg, one third of the original cast iron plate.
It’s visible, that aluminum has a broad application prospects in the automotive industry, and especially the ultra-high strength aluminum has the vital role in the development of automobile industry because of its excellent specific strength.