DaimlerChrysler has unveiled a new “bionic” concept car that achieves outstanding results for fuel consumption and emissions with a combination of diesel engine technology, innovative emission control methods and aerodynamic design inspired by a natural example.
The Mercedes-Benz bionic car seats four, delivers better than 70 mpg in the US test cycle and exceeds Euro 4 emissions standards. It is premiering at the DaimlerChrysler Innovation Symposium in Washington.
Bionics is an inter-disciplinary subject which combines engineering science, architecture and mathematics. The basic principle is to understand nature’s ideas and problem solutions, which have stood the test of time over millions of years of evolution, and to adopt them for human use.
The design engineers looked for a specific design example in nature that could map to an aerodynamic, safe, comfortable and environmentally compatible car not just in terms of details, but as a formal and structural whole. The model they chose was the boxfish.
|The boxfish.||The DCX Bionic Car.|
Despite its boxy, cube-shaped body, this tropical fish is in fact outstandingly streamlined. With an accurately constructed model of the boxfish, the engineers in Stuttgart were able to achieve a wind drag coefficient of just 0.06 in the wind tunnel.
Specialists at DaimlerChrysler first created a 1:4 car model whose shape was substantially based on the boxfish. During tests in the wind tunnel, a drag coefficient of 0.095—a previously unprecedented value in automotive engineering—was measured for this clay model.
DaimlerChrysler utilized the findings from this research in designing it concept car, which offers a Cd value of just 0.19—among the most aerodynamically efficient in this size category.
The car uses a 4-cylinder, 2-liter common rail diesel that delivers 103 kW (140 hp) of power and 300 Nm torque. In the EU driving cycle the concept car has a fuel consumption of 4.3 liters per 100 kilometers (55 mpg US)—20% less than a comparable series-production car.
Measured using US testing procedure, the car offers approximately 70 mpg (3.4 liters/100km), about 30% better than for a standard-production car.
At a constant speed of 90 km/h (56 mph) the direct-injection diesel unit consumes only 2.8 liters per 100 kilometers, corresponding to 84 miles per gallon US.
The car uses DaimlerChrysler’s Selective Catalytic Reduction (SCR) technology—more widely used in the commercial vehicle sector—to reduce NOx emissions. This aftertreatment sprays an aqueous urea solution into the exhaust system in precisely metered quantities, depending on the engine operating status. The reaction converts the nitrogen oxides into nitrogen and water.
The process requires a separate reservoir for this service fluid, which, in the concept car, is located in the spare wheel recess, and offers enough capacity to last a typical service interval for a Mercedes diesel.
(As an aside, Ford also used an SCR system in its Meta One diesel-hybrid concept car. Earlier post.)
DaimlerChrysler will initially offer passenger car SCR technology in the US when its trials have been completed.
|Mercedes-Benz Bionic Diesel Concept|
|Length / Width / Height (mm)||4,243 / 1,815 / 1,594|
|Engine Power||103 kW (140 hp)|
|Torque||300 Nm (221 lb-ft)|
|Fuel cons. (Euro)||4.31 l/100km (55 mpg US)|
|Fuel cons. (US)||3.4 l/100km (70 mpg US)|
|Acceleration 0–100km/h||8.2 sec|
|Maximum speed||190 km/h (118 mph)|