Clean Diesel—One Way to Meet Higher CAFE Standards

The House of Representatives yesterday passed an energy bill that would require automakers to raise the fleet average fuel efficiency for passenger vehicles to 35 miles per gallon by 2020. It’s unclear what parts of the bill might ultimately become law, given strong opposition in the Senate and at the White House to other provisions such as the rescinding of tax breaks for oil companies and a requirement that electrical utilities generate 15 percent of their energy from renewable sources. But for the first time since the 1970s, it seems conceivable that carmakers will be forced to look at new technologies to reduce fuel consumption. And a blog post today by local cleantech executive Bilal Zuberi argues that diesel-fueled cars, of all things, should be part of the solution.

We’re not talking about your father’s noisy, soot-spewing diesel engines here. (My own father, in fact, had a diesel VW Jetta in the early 1980s that got great mileage but produced a frightening amount of black exhaust when you started it up. If you could start it at all—the Michigan winters tended to make the fuel turn to jelly, and for some reason you had to bring the battery indoors on cold nights, like a pet.)

No, Zuberi’s company, GEO2 Technologies of Woburn, is working on components for a new generation of low-RPM diesel engines that actually produce lower emissions—and get better mileage—than conventional gasoline engines. As we explained in an October profile, GEO2’s microfiber ceramic filters are designed to make current emissions control systems for diesel engines cheaper by combining two subsystems (the particle filtration system and the oxidation catalyst, which gets rid of unburned hydrocarbons) into one. That could speed the adoption of diesel technology in North America, which is way behind Europe and Japan when it comes to the spread of clean diesel.

Rather than promoting gas-electric hybrids like the Toyota Prius, Zuberi thinks the regulators should push automakers to turn to the “best available technology” to improve fleet standards, including clean diesel. “Meeting the 35 mpg standard proposed in the new energy legislation currently before Congress will mean converting many high torque vehicles to diesel,” Zuberi argues. (By high torque he means SUVs, pickups, minivans, and large family sedans, which are heavier and therefore require more low-RPM power to accelerate.)

Zuberi, who is GEO2’s vice president of product development, gently knocks the media for not making the case for diesel clearer. “Work needs to be done to educate the public on how to evaluate the cost-benefit trade-offs when deciding on their next purchases: gasoline vs. hybrid vs. clean diesel. If not via the media, quite honestly, how is an average US consumer to know that ‘clean diesels’ have, on average, 20 to 30 percent better fuel economy than gasoline engines while providing better torque and performance and lower emissions?”

So, we’re doing our little part today. Go read Bilal’s post.

Wade Roush is a contributing editor at Xconomy. Follow @wroush

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