Audi has announced its intentions of launching lightweight springs in an upper mid-size model before the end of the year. These lightweight suspension springs are manufactured from glass fiber-reinforced polymer (GFRP) and will be available starting this fall. The springs were developed by Audi in collaboration with an Italian supplier and look slightly different compared to the conventional spring made from spring.
The green spring on the left benefits from a thicker fiber strand compared to the steel black spring on the right. In addition, it features a larger overall diameter with fewer coils while the overall weight has been reduced by a massive 40 percent. A steel spring for an upper mid-size model tips the scales at almost 2.7 kg (6 lbs) while a GFRP version weighs only 1.6 kg (3.5 lbs). This means that four GFRP springs reduce the weight of an upper mid-size model by a total of about 4.4 kg (9.7 lbs).
Ulrich Hackenberg, Member of the Board of Management for Technical Development at Audi said „The GFRP springs save weight at a crucial location in the chassis system. We are therefore making driving more precise and enhancing vibrational comfort.”
Long glass fibers are twisted together and impregnated with epoxy resin to form the core of the springs while a machine is in charge of wrapping additional fibers around this core at alternating angles of plus and minus 45 degrees to the longitudinal axis.
Audi says these lightweight springs can be tuned precisely to their respective task and the tension and compression plies mutually support each other in order to efficiently absorb the stress acting on the component. In the final production stage, the blank is cured in an oven at more than 100 degrees Celsius.
The lightweight springs do not corrode even after stone chipping and are also impervious to chemicals like wheel cleaners. Moreover, it takes less energy to manufacture GFRP springs in comparison to conventional springs made from steel.