"Multiple materials (Multi-Material)" is to use a combination of a variety of materials in auto body technology, especially the steel body frame and housing in addition to the original material, combined with the use of aluminum, magnesium, CFRP (carbon fiber reinforced composite materials) and other lightweight materials technologies. If you properly using a variety of materials depending on location, to make body weight than just the steel greatly relieved.
Lightweight materials cost dilemma faced by this technique requires. Lightweight material raw material costs are often higher than steel, and, if you like welding iron and steel materials with common welding method, and is impossible to weld different materials. To use the assembled body of dissimilar materials, you need to develop a special welding technology, factory production lines also require investment in new equipment. Therefore, multiple materials technology previously only applied to part of a premium car.
Statistics show that car 10% weight, fuel efficiency improves the tune. Like magnesium, carbon fiber composite materials to reduce weight is quite obvious.
Multiple materials is the future trend
Global automotive industry at present is to accelerate the development of multiple materials technology, the practice can improve the fuel efficiency of internal combustion engines, and reducing greenhouse gas emissions. Mercedes-Benz c-class through the use of this technique makes body (the body before painting) than previous generations models to reduce the weight of about 70kg. This improves fuel efficiency up to 30% or more.
Using multiple materials in recent years more and more technology companies, particularly European and American manufacturers. In addition to the Daimler, Germany BMW November 2013 at the European launch of EV "i3", most of the car's body using CFRP. United States Ford Motor for top-selling pickup truck "F-150" the 2015 model year equipped with aluminum body. United Kingdom Jaguar • Land Rover was launched in Europe in spring 2015 "XE", aluminum in the car's body surface area as a proportion of up to about 75%.
It is understood that the future Governments in Europe and United States and other developed countries, and increasingly strict exhaust requirements of emerging-market countries. Under EU law, the current ceiling on emissions of CO2 for newly registered vehicles is an average of 130 grams per kilometer by 2021, selling new cars within the European Union shall not exceed 95 g/km average carbon emissions, automobile emissions control by 2025 is expected to be in the 68~78 g/km. In 2015, China allowed auto makers of CO2 emissions per kilometre (sales of vehicles average) CO2 emissions of about 120g for 160g,2020 years, until 2025 only 116g.
Survey shows that by 2020, the body weight than 2014 to reduce 12% of petrol vehicles by 2030, you need to lose 37%, set up by the European emissions reduction targets can be reached.
Various factors indicate that only by using materials that countries will be more likely to achieve lightweight long-term emission reduction targets for light car. Despite the pressure on car manufacturers is very large, large-area use of lightweight materials there are many deficiencies and constraints, but it is the direction of auto material application in the future.