Mercedes-Benz Turbocharged Smart Fortwo Gets 80MPG

Do you need a hybrid to get mega-mileage? Well, maybe not. Mercedes-Benz says that its new smart fortwo cdi – an 1800 pound, 106 inch long car with a top speed of 85 mph – gets nearly 80 mpg. For perspective, consider that driving this two-passenger car 10,000 miles annually requires only 16 fill-ups during the course of the year. Amazing. Plus, along the way the smart fortwo’s 45-horsepower, three-cylinder diesel engine emits less carbon dioxide per mile than any current production car.

Located in the rear, the 799 cc turbocharged engine is the world's smallest direct-injection diesel engine. This new light alloy engine represents a 10 percent increase in power and torque as well as a 13 percent decrease in fuel consumption. Two-phase fuel injection, like that used in Mercedes-Benz C engines, injects a small amount of fuel a few milliseconds before the main injection to ignite and preheat the combustion camber. This results in a noticeably quieter combustion noise level.

Emissions are handled in two stages. Common-rail injection and extremely efficient combustion result in a low level of untreated emissions. Up to 60 percent of the previously-cooled exhaust gas is returned to the combustion chambers where it is combusted once again, greatly reducing nitrogen oxide emissions. An oxidation catalytic converter and an open diesel particle filter are responsible for exhaust gas aftertreatment.

A micro-computer controls the whole engine-transmission system, calculating how much fuel is needed along with pilot and main injection intervals. An automated manual five-speed transmission is standard and is operated by briefly tapping the shift lever on the center console. Steering wheel shift paddles are optional, as is an automatic transmission mode.

Anti-lock braking with electronic brake-force distribution, electronic stability program, brake assist, full-size airbags for driver and passenger, safety seats with integral seat belts, and a sturdy tridion safety cell make the fortwo the safest car in its class. All this is wrapped in available coupe and cabrio versions to fit different tastes, providing all the more reason for buyers to consider this stylish, pint-size wonder.

All this is good news and bad. The 2008 smart fortwo models coming to America early next year are powered by gasoline engines only. They will still get an impressive 40 mpg, but since that?s only half as much as the cdi version available in Europe, there clearly will be clamoring to bring the diesel model to American highways.