Special Coverage

Frankfurt Auto Show

FRANKFURT – If General Motors Corp. is truly serious about reducing fuel consumption in the U.S., it need only look to its Adam Opel GmbH subsidiary for inspiration.

The 1.3L CDTI Ecotec 4-cyl. turbodiesel already powers Opel’s smallest European cars, including the Astra, Corsa, Meriva and all-new Agila. In 2005, journalists from 26 countries chose the compact, fuel-efficient mill as the “Engine of the Year” for its segment.

In the Astra, which is bound for U.S. shores under the Saturn brand by year’s end, the 1.3L CDTI is paired with a 6-speed manual transmission to achieve a combined city/highway fuel economy of 49 mpg (4.8 L/100 km).

Output is a respectable 90 hp and 147 lb.-ft. (200 Nm) of torque. The Astra sprints to 62 mph (100 km/h) in 13.7 seconds and emits a paltry 130 g/km of carbon dioxide.

The numbers are impressive, but don’t count on this engine to solve GM’s fuel-economy challenges in its home market, says Vice Chairman Bob Lutz.

Upcoming U.S. diesel-emissions requirements are six times more stringent than Europe’s current code “and probably can’t be met with a diesel engine of that size,” Lutz tells journalists at the auto show here.

It also will be difficult but more feasible, he says, to adapt a larger turbodiesel – perhaps 4.5L in displacement – for application in a Chevy Tahoe or GMC Yukon SUV in the U.S. market, Lutz says.

“It’s already going to require $3,000 worth of hardware, including secondary urea injection,” he says, “and all kinds of stuff that’s not necessary in Europe.”

Lutz discounts automotive media clamoring for diesels.

“Diesels are commonly bandied about in the U.S. media that, ‘Oh, this is the solution. You get 30% greater fuel economy. All we have to do is switch to diesel,’” Lutz says. “Well, right now nobody knows how to do that at a cost level that’s commercially acceptable.”

The need for a device to trap oxides of nitrogen emissions also cannot be overlooked.

“You have to have a NOx trap, and every two minutes you need secondary injection of raw fuel into the NOx trap to burn off the NOx,” Lutz says. “And that secondary burn in the converter actually reduces the fuel-economy gain of a diesel by about 40%.”

Instead, Lutz is more enthusiastic about GM’s research into homogeneous charge compression ignition (HCCI), a concept that blends the best attributes of gasoline and diesel engines.

For instance, a conventional gasoline engine can switch to spark-less compression-ignition under light loads, improving fuel economy and reducing emissions.

HCCI allows gasoline engines to nearly match the efficiency of diesels. “Pretty soon they’re at about the same level,” Lutz says.

Meanwhile, the 1.3L CDTI also rolls on to the Frankfurt stage in the Opel Flextreme concept car, a plug-in electric vehicle that springs from GM’s E-Flex architecture.

The diesel engine is not connected mechanically to the wheels but instead charges a lithium-ion battery pack, which powers an electric motor to propel the Flextreme up to 34 miles (55 km) in pure electric-drive mode.

GM Europe President Carl-Peter Forster says 75% of all European commuters travel no more than 34 miles (55 km) per day.

“Based on this assumption, the Flextreme would solely run on the energy provided by the batteries, and with that be completely emission free,” Forster says.

Once the diesel engine kicks in, the Flextreme can run nonstop and still achieve 156 mpg (1.5 L/100 km).

The 1.3L CDTI also drives the new Corsa EcoFlex, which debuts at the Frankfurt show equipped with a diesel particulate filter. It emits a mere 119 g/km, which equates to fuel economy of 52 mpg (4.5 L/100 km).

The Corsa EcoFlex will be available in Europe beginning in January. EcoFlex variants of the Opel Meriva and Astra, powered by the 1.3L turbodiesel, also will be available by year’s end.

In addition, as part of the EcoFlex program, Opel unveils at Frankfurt a Corsa Hybrid concept that combines the 1.3L CDTI with GM’s belt-alternator-starter technology. Fuel economy is estimated at 63 mpg (3.7 L/100 km).

Elsewhere in the GM product range, Cadillac debuts the BLS Wagon (similar in size to the CTS sedan in the U.S.), with two new available engines: a 2.0L Flexpower mill that runs on E85 bioethanol fuel or a 1.9L 2-stage turbodiesel.

Saab premiers its Turbo X version of the refreshed 9-3 sedan. The 280-hp Turbo X is the first Saab equipped with all-wheel drive and dashes to 62 mph in 5.7 seconds, the auto maker says.

Lutz says the BLS Wagon definitely will not come to the U.S. because it would be too expensive to ship from Europe.

But the Turbo X will arrive in the U.S., although Lutz says he does not know when.

“It will be about the same time as in Europe,” he says. “We expect the U.S. to be a prime market for it.”

tmurphy@wardsauto.com