Bill Sharfman from The Scientist has a great subscription piece covering the design story behind last year's Mercedes-Benz Bionic concept car; and hopefully this reawakening of interest is a sign that we're going to see it on car lots in the upcoming year. Ten years ago, engineers from the Mercedes R&D department were searching for a natural shape that would make a good car. They toured a large fish collection at the Rosenstein Museum and discovered a cute little tropical fish that lives in coral reefs. The boxfish tuned out to be the perfect shape for a four seater compact car.
An anatomically correct model of a female boxfish has a drag coefficient of .06; the Bionic car prototype weighed in at 0.19. This may sound like a large loss of efficiency, but my Mercedes E320 has a drag coefficient of 0.29, and at the time was considered to be an amazing feat of engineering. To reduce drag, door handles were motorized to pop out of the door on demand, and the rear view mirrors were shaved off the side in favor of cameras and monitors. By starting from shapes in nature with good aerodynamics, the concept engineers were able to avoid reinventing the wheel and able to concentrate on fitting it with modern technology under the hood.
The goal of the Bionic concept was to produce an ultra aerodynamic car that would offer fuel efficiency and low emissions. The prototype ran at seventy miles per gallon for city driving, and eighty-four mpg on the highway. By maximizing the utility of the combustion process within the engine. the resulting emissions are actually more polluting than previous technology. Though, by treating the pollutants before they leave the tailpipe, the overall system is better for the environment. This Selective Catalytic Reduction system applies a liquid solution of urea from AdBlue to the emissions. Precise timing is used to spray small amounts of the reactant into the tailpipes to breakdown nasty nitrogen oxide into harmless water and nitrogen.
Good looks, neat techie features, fuel efficiency, and low emissions? Hey Mercedes, cowboy up and get the boxfish on the lot!