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July 28, 2010 Vol. 6, No. 15

Oh boy, here we go again. Being a mature fellow with many miles under my shoe leather, I should have known that the EGR vs. SCR battle was far from over. What was I thinking?

Truth be told, I just hoped it was over, never actually thought it possible in a skinny little marketplace so rife with competitive testosterone. And really, why should it be a thing of the past? Gazillions of truck buyers, preparing to put money down for new trucks in the next few months or maybe next year, are confused. Scared crapless by the engine problems that some folks have unwittingly bought over the last few years, they have little wish to risk much at all. Which isn’t to mention the increased running costs that everyone has suffered. And while some have committed to one emissions technology or the other, the vast majority really don’t know what to do.

So here’s my perspective: I still maintain that we won’t know how these engines perform for at least two years, not until an awful lot of user miles have been driven.

In the good old days when freight was plentiful and rates were actually compensatory — such a concept — things like engine choice didn’t matter so much. Margins were thick and spec’ing mistakes could be swallowed. They’d hurt, sure, but they wouldn’t threaten to bring the house down in flames. Not so in 2010. We all know there are dozens of fleets still out there only because the bank didn’t want the trucks back, and it’s obvious that margins for a great many truck operators are razor thin, so a spec’ing choke today could be very serious indeed.

The selective catalytic reduction crowd (Cummins, Daimler, Mack/Volvo, Hino, Mitsubishi, etc.) has been telling us for months now that their 2010 engines will deliver something in the range of a 3-to-5% improvement in fuel efficiency over the earlier EGR models, less the attendant consumption of diesel exhaust fluid. All of them have said in their various ways that on-road testing — some of it by customers, latterly — confirms this gain. As sales tools go, that ain’t so bad.

Daimler Trucks North America says its EPA-2010 engines have done 30 million test miles, ” including several million customer freight hauling miles in DTNA EPA-2010 trucks.”

Navistar, sole proponent of an in-cylinder solution to the NOx challenge by way of what it calls ‘advanced exhaust gas recirculation’, has until now been pretty silent on the issue of fuel economy and on testing. Its MaxxForce engines, the company has been saying, are the better choice because their emissions fix is simpler, already well understood by users, and requires nothing like the occasional replenishment of a DEF tank. Not bad sales tools there either in some eyes.

But last week, Navistar’s senior vice president Jim Hebe led an online press conference in which he and a pair of colleagues announced the results of some fuel testing done for them by Ohio’s well respected Transportation Research Center. They also introduced a new and seemingly logical term — not fuel economy but ‘fluid economy’, reasoning that SCR engines consume DEF as well as diesel fuel and any competitive measurement should really account for both tanks.

Lo and behold, the MaxxForce 13 [pictured here] won the day. Installed in a ProStar tractor, it’s claimed to have bettered a Cummins ISX in a Kenworth T660 by 2.5% and a Detroit Diesel DD15 in a Freightliner Cascadia by 1%. Remember now, they’re talking total fluid consumption.

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

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