Mercedes-Benz announced its first four-cylinder diesel in the U.S. market with the 2013 GLK, and if buyers take to it the way Mercedes is hoping, it may not be the last model to adopt the four-pot diesel.

Previously the company has sold five- and six-cylinder diesels in the U.S. market, but the 2.1 BlueTEC found in the GLK will be the firm's first four-cylinder diesel... at least in the U.S.

Mercedes is predicting that buyers will take to the extra efficiency--and the engine's other benefits. Gunter Fischer, project manager for the Mercedes SL roadster, told Wards Auto that buyers would take to the class-leading economy but also appreciate the extra torque.

The GLK's 2.1-liter unit will also be the most powerful four-cylinder diesel sold in the U.S. It's ideally suited to smaller cars like the GLK, C-Class and upcoming A-Class compact, but potentially it could also serve buyers of larger vehicles, like the E-Class and S-Class--if buyers can get over the "small engine, large car" factor.

While Mercedes has confirmed the new A-Class will sell in the U.S. (unlike its predecessor), a diesel unit hasn't been confirmed yet. The European-market A-Class will receive efficient 1.8 and 2.0-liter diesels. Every model in the European Mercedes range is available with at least one diesel unit.

There's still an extra cost to producing diesel cars, which is just one of the reasons the cars haven't gained popularity in the same way they have in Europe--the cost of the fuel itself being another.

Larger diesels in the U.S. require urea injection to reduce oxides of nitrogen from the exhaust, which adds to the cost of the vehicles and requires topping up. This puts some buyers off, but does make the cars significantly cleaner.

Fischer predicts that in the future, urea injection will be required in diesels sold across the world. While diesels are still more efficient than gasoline engines, this could make the cars less popular even in Europe--where, like the U.S, gasoline vehicles are getting ever more efficient.

Still, fans of diesel will be pleased to hear Mercedes' commitment to the fuel, where it will allow levels of efficiency greater than Mercedes customers have experienced before...


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