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Why GM's 2.0-liter diesel is cleaner in America's Cruze than it is in Europe

Chevrolet Cruze 2.0 Turbo Diesel Engine
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The 2014 Chevrolet Cruze will have three different engine options soon, including the new 2.0-liter diesel powerplant that is debuting here at the Chicago Auto Show. The other powertrain choices include the made-in-Toledo 1.4 turbo gas engine used in the Eco and upper trim models and the 1.8-liter gas engine (made in Toluca, Mexico; it is also built elsewhere for other vehicles). The diesel is made in Kaiserslautern, Germany. In short, this is an example of GM's global network, and the oil-burner is a long-term player in the game: the basic architecture of this engine has been sold since 1985. GM sold over a half-million diesel-powered cars around the world in the last year, including 33,000 Cruze diesels. In Europe, 40-percent of Cruze sales are diesel. The engine is currently used in a number of General Motors vehicles in Europe, including Zafira, Astra and Insignia models from Opel.

Well, almost. Mike Siegrist, chief engineer behind the US engine, tells AutoblogGreen that Chevrolet engineers in the US worked with GM's team in Torino, Italy to adapt the powerplant for GM's first US diesel passenger car since the 1986 Chevette. To do this, the team tinkered with four main aspects: emissions, diagnostics, environmental conditions (that is, how hot or cold it is outside) and altitude. Siegrist notes the US has higher paved roads – Mount Evans in Colorado, for example – than Europe does, and it also has stricter emissions regulations, all of which necessitated the changes.

Thus, the US Cruze TD has a new intake manifold and throttle body system and an increased capacity exhaust gas recirculation (EGR) cooler that offers better NOx control, Siegrist said. A common rail piezo injection system running at 1,600 bar (the European engine runs at 2,000 bar) offers "really, really good fuel control," Siegrist says. To start in colder conditions, the US diesel engine has ceramic glow plugs while the Europeans get metal glow plugs. There is also an engine oil heater that can be plugged in if you're trying to start the Cruze in frostbite conditions.

With all of these changes, the US 2.0 turbodiesel engine actually ends up being cleaner than the European model. Siegrist wouldn't venture a guess as to how much cleaner, exactly, but he did say it meets the stricter US standards and that, "the margin's bigger than what you think." So, for all those times when we wished we could taste the forbidden fruit of a European powertrain, this is a chance for America to get the better – or at least cleaner – end of the bargain. Unfortunately, tuning for US emissions and fuel also means we get less power. The estimated power output of the 2.0-liter diesel in the US is 148 horsepower, but its European counterpart enjoys 163. The price of progress.

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