Audi presented the A5 coupe prototype, a new concept that focuses on efforts to develop lightweight vehicles. The prototype utilizes several weight-reduction technologies, which all aim to improve fuel economy, cut CO2 emissions and enhance handling.
The weight is cut by around 100 kilos as compared to the standard model. Instead of steel construction, it has advanced aluminum and carbon fiber, with the Audi Space Frame (ASF) playing a key role in Audi's efforts to cut the vehicle's weight.
"Use of the ASF principle reduces the weight of a car body by at least 40 per cent compared with conventional steel construction, and this shows in a kerb weight of 1,310kg for the aluminum A5 prototype, versus a total of 1,420kg for the equivalent steel-bodied series production model," the company said. The prototype is powered by a 2.0-liter four-cylinder engine that develops 211 hp and achieves a power-to-weight ratio of 161 hp per ton.
Audi added that the new A5 Coupe's lightweight design enables a smaller engine to supplement a larger one with no impact on performance and gains in economy and emissions. It also has a knock-on effect on ancillaries such as the brakes and transmission, which can also be reduced in size and weight.
Use of the ASF principle reduces the weight of a car body by at least 40 per cent compared with conventional steel construction, and this shows in a kerb weight of 1,310kg for Audi’s aluminium A5 prototype, versus a total of 1,420kg for the equivalent steel-bodied series production model. By fusing the patented aluminum Audi Space Frame with carbon fibre-reinforced plastic materials, Audi has succeeded in reducing the weight of the A5 prototype.
The prototype is 40 per cent lighter than the production model of the A5, which employed a heavier steel construction for the body. Weighing only 1,310 kilograms as opposed to the 1,420-kg steel-bodied production model, the A5 prototype is equipped with a four-cylinder engine that nevertheless has a V6-rated performance. The 2.0-liter 211PS Turbo FSI engine also possesses outstanding fuel economy and reduced emissions despite the exceptional performance.
The aluminum prototype A5 also has a power-to-weight ratio of 161PS per tonne. Compare this to the standard 3.2-liter FSI V6 quattro engine in the production model A5 – 265PS, and 172PS per tonne. The two engines are not distant to each other in terms of performance, but the FSI V6 quattro engine makes the production model A5 significantly heavier at 1,540 kg. The focus on lightweight design has resulted to smaller and lighter transmission and braking system as well.
This has effects on the car’s handling and performance – the test car has been observed to turn and drive at a pace that’s smoother than the heavier production model of the A5. The aluminum-centric ASF concept has already been in use since 1993 beginning with the A8. The ASF featured prominently in the designs of the A8 luxury saloon, A2 compact hatchback and the R8 supercar. Even the TT Coupe and Roadster also employed the ASF concept in the design, combining it with partial steel construction.
This allows engineers to balance the distribution of weight in these two vehicles. Audi AG’s board member for Technical Development Michael Dick stated that Audi has made lightweight designing as a foundation for developing fuel efficient vehicles. Mr. Dick said that Audi has also identified the reversal of the weight spiral as one of its long-term goals.
ASF concept has been instrumental to Audi’s efforts to realize weight savings in the design of their vehicles, allowing its engineers to focus more on driving performance and dynamics as well as fuel efficiency. The concept, throughout the years, has determined several indicators that determine the relationship between weight and fuel consumption.
Beginning with the A8 in 1993, Audi engineers have noted that a 100-kilogram reduction in weight translates to a 0.3 to 0.5-liter improvement in fuel consumption for 100 kilometers’ riding distance. The reduced fuel consumption also cut the A8’s CO2 emissions by 8 to 11 grams per kilometer.
The ASF concept will prove to be instrumental in the designs of future electric vehicles. Its focus on using aluminum will make it central to the development of electric vehicles, which will feature heavy batteries.
With the weight already taken up by the batteries, there is a need to use lighter materials to ensure continued fuel efficiency and performance. Audi has the right experience and expertise in responding to that need – more than 550,000 vehicles have already rolled out of Audi’s manufacturing plants with aluminum bodies.