SCR vs EGR, THAT IS THE QUESTION

Rolf Lockwood

April 9, 2008 Vol. 4, No. 8

With a huge sigh of relief, I can tell you that the 37th annual Mid-America Trucking Show has come and gone. I say ‘relief’ because it’s a very, very busy place. The show, known as MATS, opens on Thursday for the masses, but things start with a Cummins dinner on Tuesday night for most of us in the press. And it never slows down after that.

That said, the annual trek to Louisville, Kentucky is also a lot of fun for a gearhead like yours truly. All that hardware!

And this year some controversy, a lot of it, about emissions solutions for 2010. This was bound to happen. Following disparaging comments about selective catalytic reduction made by International Truck & Engine president Dee Kapur a couple of months ago (see the link below to our Newsfirst story), there was a response from Freightliner – sorry, I mean Daimler Trucks North America (DTNA) — in Louisville. Senior marketing vice president Mike Delaney threw down the gauntlet at the company’s annual MATS breakfast, devoting his entire presentation to “…dispelling the SCR misinformation being tossed about.”

Earlier in the press conference, DTNA president and CEO Chris Patterson made the company’s 2010 plans clear, though they’d been known for more than a year.

“We will be utilizing Daimler’s BlueTec technology for our Detroit Diesel engines beginning in 2010,” he said. “The technology is clearly the best choice for our customers… the only means of meeting the stringent 0.2 g/kWh NOx standard for heavy-duty diesel engines in 2010 while actually reducing diesel fuel consumption in comparison with the technology used in 2007 engines.”

“BlueTec” is the Daimler moniker that refers to the urea that will be injected into the aftertreatment system of 2010 SCR engines, though it appears to have a new formal name – DEF, an acronym for Diesel Exhaust Fluid. As if we need another acronym.

Urea works with exhaust heat and a catalyst to convert nitrous-oxide emissions into harmless pure nitrogen and water vapor. Trucks using SCR will have an extra tank, with a capacity ranging from five to perhaps 30 gal, hanging from the frame rails to hold the urea supply. In some cases frame space is at a serious premium, so this could be a challenge in some configurations.

But let’s set the larger stage here. Clearly, we’re going to have a split down the middle of the market, with some engines using SCR and some not. On the SCR side we have Mack/Volvo and Detroit Diesel, plus the new engines coming from Paccar in 2010, based on the European DAF motor. On the other side we have International, with its heavy-duty MaxxForce engines co-developed with Germany’s MAN, and Cummins. The latter pair say they’ll continue to use cooled exhaust gas recirculation (EGR) and diesel particulate filters (DPF) for on-highway trucks, just as they do now. They say EPA standards can be achieved by in-cylinder means, and they won’t need any other form of NOx aftertreatment.

Caterpillar, amidst rampant speculation about its future intentions – maybe even becoming a truck builder via some sort of link with Navistar? – has yet to make a 2010 pronouncement.

Cummins vice president and heavy-duty engine chief Steve Charlton says not much will actually change in his company’s ‘010 motors. Next-generation EGR doesn’t add complexity, he says, and power, torque, fuel economy and maintenance intervals will remain the same as today. Engineering development, as I told you in my last newsletter, is going smoothly, he says.

Rolf Lockwood

Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to Trucknews.com.

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