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Environmental gains with the right design

Green advisor

As long as cars have been around, so has the search for the perfect, streamlined speedster. Faster, narrower and smoother lines have been the guiding lights for minimising air resistance, maximising speed.

Together with ÅF, Volvo Cars has developed a concept car that has an air resistance coefficient corresponding to Cd*= 0.20, a figure that represents a magic limit in the automotive industry.

Volvo Cars has taken the baton for aerodynamic development, but with their sights set on another goal. A smarter design for a better climate.

Volvo Cars and the magic limit

The correlation between air resistance and fuel consumption is well known. The basic equation is simple: an improvement in aerodynamics of about 30 percent results in a reduction in fuel consumption of 15 percent.

Efforts to attain an aerodynamic, efficient car have always been of interest to Volvo Cars. The aim is to achieve an air resistance coefficient corresponding to Cd*= 0.20, a figure that represents a magic limit in the automotive industry. The lower the figure, the lower the resistance. For a comparable production car, the Cd value is about 0.31.

"Together with ÅF we achieved the goal of 0.20 for the concept car," says Alexander Broniewicz, project manager at Volvo Cars.

Air resistance and emissions closely related

Optimised aerodynamics are key to a more climate smart car.
"The car's proportions, chassis, body, tyres and rims – everything affects air resistance. It's about working with every part, creating smooth transitions and avoiding disruptions in the air flow," explains Per Hamlin, analysis engineer at ÅF.

Developing an aerodynamically innovative, fuel efficient car that looks and feels like a modern Volvo has required close collaboration within the project group. The design department at Volvo Cars were involved in the project from the start.

A virtual car was produced to enable the use of software to test various aerodynamic solutions to optimise air resistance. A full-scale prototype made out of clay was also built and tested in Volvo's wind tunnel, which provided the conclusive results.

Volvo Cars was in charge of project management while ÅF was responsible for the aerodynamic calculations and analyses, which provided the foundation for being able to design the car in the necessary manner.

"In many respects, the car's design and aerodynamics contribute more to reduced emissions than refined engines. There's an oversimplified idea that e missions are only related to the vehicle's engine or new types of fuel," says Per Hamlin.

The so-called magic limit that was reached for the concept car's air resistance coefficient at Volvo Cars is a figure that confirms the project's success. But the greatest achievement, according to Volvo Cars' Alexander Broniewicz, is the form of collaboration, rather than the outcome:

"Now that we've tested and developed a number of different projects together with the design department, we achieve even better results. And that's something we can benefit from in future projects."

* Cd stands for drag coefficient and represents the aero-dynamic force affecting a vehicle in motion.