Photo: 2017 Chevy Cruze

By: John Voelcker | GreenCarReports.com | Feb 27, 2017

Diesel engines will continue to appear in pickup trucks, European luxury SUVs, and at least a few mass-market crossover utility vehicles. Two of those are the Chevrolet Equinox and Mazda CX-5 crossovers that will launch for the 2018 model year. But the future of diesel in U.S. passenger cars remains far more up in the air, due to a confluence of events.

Those include continuing low gasoline prices and the high cost of necessary diesel exhaust aftertreatment systems to keep their emissions within legal limits.

Perhaps highest in public awareness, however, is the Volkswagen diesel scandal, which over its 17 months has completely removed Volkswagen, Audi, and Porsche from the business of selling diesel vehicles in North America.

The bulk of the VW Groups' diesel sales were compact and mid-size passenger cars.

Now, only GM is left selling diesel passenger cars in the U.S. at the moment, in the form of its compact 2017 Chevrolet Cruze Diesel four-door sedan and five-door hatchback.

But Dan Nicholson, GM's vice president of propulsion, wants green-car buyers not to discount diesels out of hand.

They continue to offer, he notes, superior fuel economy and lower carbon-dioxide emissions than gasoline engines of comparable power in the same models.

In an interview last week with Green Car Reports, Nicholson and assistant chief diesel engineer Mike Siegrist suggested that Chevy expects the latest Cruze Diesel to do considerably better than the first-generation model sold in small numbers from 2014 through 2016.

Calling the prospects for the diesel Cruze "promising," Nicholson suggested that GM would be happy if diesel penetration in Chevrolet's compact diesel cars reached 10 percent of sales.

That's the current level of diesel penetration in GM's Chevy Colorado and GMC Canyon mid-size pickup trucks, in which a 2.8-liter 4-cylinder turbodiesel engine has been a strong seller.

Nicholson acknowledged commentary from European outlets that diesel penetration in that region—now roughly one in two vehicles sold—had peaked and would likely descend.

It might "float down to a soft landing," he suggested, but will likely not plummet and crash.

As for the U.S., though, the GM executive reiterated that "carbon dioxide and fuel economy" should be the prime lens through which all green-oriented buyers should consider diesel vehicles.

Asked about the relative wells-to-wheels carbon footprints of driving a mile on grid power versus burning hydrocarbon fuels in a combustion engine, Nicholson pivoted seamlessly.

GM offers two very good plug-in vehicles, he noted, the Chevrolet Bolt EV electric car with 238 miles of range and the Chevrolet Volt plug-in hybrid with 53 miles of range and the ability to use gasoline when needed for longer trips.

But, he suggested, those vehicles may not be ideal for every buyer—and diesel offers another way to reduce the carbon footprint of personal transport.

"Your readers can feel good," he continued, "that our [diesel] vehicles meet the most stringent U.S. [emission] standards and deliver great carbon-dioxide numbers too."

The company's message, then, boils down to diesel being a perfectly acceptable technology for clean air—despite VW Group's sins—and more favorable than gasoline on carbon dioxide per-mile emissions.

Whether that message resonates with compact-car buyers remains to be seen.