[The Automotive Enthusiast]

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The past 16 months have been something of a stress test, not just for Volkswagen but for the diesel auto market as a whole. Volkswagen’s diesel emissions scandal brought increased EPA scrutiny, resulting in established models from Mercedes-Benz and BMW put on hold and hopes of ever seeing performance diesels such as the Volkswagen GTD and BMW’s awesome new quad-turbo “super diesel” effectively dashed.

With diesel versions of the Mazda CX-5, Chevrolet Equinox, and Ford F-150 all due this year—as well as the return of the Chevrolet Cruze diesel—it would be premature to call diesels dead for the United States. Yet with VW sitting it out, Audi considering diesel only for SUVs, and Mercedes-Benz in the process of reevaluating its product plans, the market is hardly continuing where it left off. So we asked Fritz Steinparzer, BMW’s global head of diesel-engine development, how the diesel turmoil will affect BMW.

To sum up: He’s pragmatically optimistic about diesels’ future in the BMW product mix—although it’s clear that what happens in Europe over the next few years will ultimately drive the technology’s U.S. fate.

Diesels have made up more than 50 percent of new-vehicle sales in Europe in recent years, but a recent study anticipated that diesels will comprise just 9 percent of that market by 2030. That’s partly due to tougher new emissions rules and the cost of meeting them. The baton is expected to be passed from diesel to hybrid and electric models, especially among small cars—and that could impact what we see in the U.S.

We’ll see a continued downward trend in diesel small-car sales globally, Steinparzer admitted. “But in the bigger, heavier cars, from the customer point of view, diesels are still a very robust solution,” he said. In the U.S., it’s far less a matter of meeting technical hurdles than a discussion with the public. “For passenger cars, if there is enough customer demand we will offer it,” Steinparzer said, “because technically, the solution to meet regulatory demands, we have it.”

The EPA and CARB did a lot of additional tests to other manufacturers’ products after the VW issue, according to Steinparzer. “They never had a problem with our cars here [in the U.S.],” he said, emphasizing that he prefers the American approach and its well-defined driving cycles over Europe’s emissions standards, which are based on engine tests and often don’t correlate well to tailpipe emissions. More realistic driving-based emissions testing methods for Europe will commence in September, and a tighter set of limits will go into effect in 2020.

Meeting U.S. Diesel Emissions Regulations Isn’t the Real Issue

In order to make diesels progressively cleaner in the future, better fuels aren’t necessary, according to Steinparzer, because BMW has a toolbox of several strategies available. Those include further improvements to the injection system and combustion process—to drive down raw “engine out” emissions—and/or applying wider exhaust gas recirculation (EGR) strategies that work closer to full load. And because urea-injection systems, which spray a solution into the hot exhaust stream to reduce NOx, work best in a specific temperature range (540 to 930 degrees Fahrenheit), engineers are considering either a post-injection system or an electrically heated catalyst for the exhaust system. BMW diesels are also due to get a new round of updates to their onboard diagnostics, Steinparzer said.

EPA scrutiny led BMW to suspend production of its U.S.-spec diesel models in late 2016. Although those models were cleared after some additional emissions testing and recertified by late summer, it has taken time to bring them back into the mix. BMW 328d models returned to dealerships in October, while X3 xDrive28d models returned in December; fresh stocks of the BMW X5 xDrive35d are arriving in dealerships this month.

That said, there’s some hope in the numbers. To our request about pent-up demand for diesels, BMW pointed to sales of the 3-series family, which were up more than 28 percent in December versus the same month in 2015. Although BMW North America doesn’t break sales down by submodel—and that increase could include more than a few of the 330e iPerformance plug-in hybrid that was also introduced during this same period—we hear a clear message from BMW: Diesels are here to stay, hopefully for a long time.

http://blog.caranddriver.com/bmw-sti...united-states/