Mercedes announced a new line-up that would feature its well-known luxury cars, but with a little twist. That twist, it turns out, is that these models, dubbed "Blue Efficiency," would be modified to optimize fuel economy and not power output. So far three C-Class models have been released, in both diesel and gasoline versions. The most impressive of the group is easily the 200 CDI. This 2.2L diesel engine delivers 134 hp, 199 lb-ft of torque, and an extremely admirable 46.1 mpg (up from 38.6 in the non-Blue Efficiency model). In its Blue Efficiency line-up Mercedes employs what is called passive modifications. In the Blue Efficiency models Mercedes shaved weight with lighter windows, less sound-proofing, and a thinner windshield. To reduce aerodynamic drag the car was lowered, has part of the grill blocked, and had some protrusions like mirrors and door handles optimized. This all makes for a more efficient car that the public is likely not to notice. Mercedes has discussed making this package available for every one of its models. If that happens, many more drivers will have a chance to get better fuel economy, and without losing out in style, comfort or speed. Certainly a step in the right direction. Rather than requiring the driver to do something to get better fuel economy, the efficiency is "built in." This means that even the most lead-footed of drivers will end up saving, whether they like it or not.

Most of the modifications were made to either the weight of the car or the car's aerodynamics. In the auto design world, these two items are usually considered low-hanging fruit. Let's hope the ride quality isn't compromised for the sake of fuel efficiency.

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