Corrected 3/13/2011. Navistar International is looking at some "exciting technologies" to reduce oxides of nitrogen in the exhaust of its later diesels, but aftertreatment using urea -- at least in liquid form -- will not be one of them.
Jim Hebe, senior vice president, North American sales operations, discussed future emissions technology at The Work Truck Show.
Jim Hebe, senior vice president, North American sales operations, discussed future emissions technology at The Work Truck Show.

Navistar's engines must get down to the absolute levels demanded by the federal Environmental Protection Agency in its 2010 emissions standard. "Point 2" - the required 0.2 gram per horsepower-hour for oxides of nitrogen, or NOx - is Navistar's goal after a period when its current diesels emit slightly more than that, said Jim Hebe, senior vice president for North American sales operations, in a press conference during the Work Truck Show in Indianapolis.

For now, Navistar and one other builder are using credits earned in the past by producing cleaner-than-necessary engines sooner than required. Navistar engineers are looking at methods not at hand when they decided to go with Advanced Exhaust Gas Recirculation. A-EGR cuts NOx emissions within the cylinders instead of using liquid urea aftertreatment, as all competitors are.

"We always said we would stay with in-cylinder [NOx reduction] unless we found something better," Hebe said at the press conference. A-EGR bought Navistar time to consider other methods, and "fortunately, there are some exciting technologies out there that we never had before -- one of them ours."

One of those technologies could be a solid form of urea injection being developed by Amminex, a Danish company Navistar invested in last year. Solid urea would not require operators to replenish the liquid urea supply - called diesel exhaust fluid - which they must do with selective catalytic reduction, the method chosen for 2010 by most other truck-diesel makers here and abroad. Hebe and other Navistar executives have been vociferous in their criticism of SCR.

I wonder what solid urea injection would cost. Would fuel economy be better, as competitors now claim for their SCR engines? How much would a dealer charge to change out the canister containing the urea-impregnated salt? Might it be more costly and inconvenient than just pouring some diesel exhaust fluid into a tank?

Such questions are premature until Navistar announces what it will do to get to point 2 after its EPA credits run out, and they're still considering the possibilities. Any form of exhaust aftertreatment chosen by Navistar would apply only to its heavy-duty engines. Medium-duty engines will still be dealt with in-cylinder.

Editor's Note: This article was corrected 3/13/2011, replacing a previous version that indicated Navistar might consider liquid urea injection. After checking with other reporters at the event, we realized our reporter misinterpreted Mr. Hebe's remarks. We regret the error.