Cummins Reverses Course, Will Use SCR for 2010 Engines
By Frederick Kiel, Staff Reporter
This story appears in the Aug. 18 Print Edition of Transport Topics.
Engine manufacturer Cummins Inc. last week reversed its decision to use only exhaust-gas recirculation to meet 2010 emission standards and said it would instead use urea-based selective catalytic reduction to cut the new engines’ fuel consumption.
“Our SCR system will deliver up to a 5% increase in fuel efficiency over today’s solution, and that was the most compelling reason to make this change,” Jeffrey Jones, vice president for sales and market communications, said Aug 13.
Company officials said that fuel prices have soared 70% since Cummins originally rejected SCR for its heavy-duty engines.
In September 2007, Cummins executives said SCR was impractical for over-the-road trucks because drivers would have to constantly replenish the trucks’ supply of urea, an essential ingredient in the system’s process of converting nitrogen oxides to harmless nitrogen and water. (10-1, p. 1).
They also had said that meeting tighter federal standards for emissions of NOx and soot using enhanced EGR would offer truck buyers engines with known, familiar technology.
However, “after a significant amount of thrashing it out and thinking, in light of new inventions and the drift in fuel pricing going up 70%, we decided to take a deeper look at fuel economy, and that formed the backbone of our decision,” Jim Kelly, president of Cummins’ engine division, said last week.
“The development of copper-zeolite for a catalyst that has very good properties for NOx conversion has allowed us to optimize engine and aftertreatment performance, for better fuel mileage and to meet EPA standards,” said Steve Charlton, Cummins’ vice president of heavy-duty engineering.
Charlton said copper-zeolite became available for commercial use only nine to 12 months ago and “proved far superior to the iron-zeolite catalyst available when Cummins ran its original SCR tests three years ago.”
Cummins’ reversal leaves Navistar Inc., which has begun marketing its own heavy-duty engines for International trucks, as the only engine manufacturer planning to use EGR to meet 2010 emissions. Caterpillar Inc. announced earlier this year it would end heavy engine production after 2009.
But although Navistar will use its own engines in International trucks, it also will offer Cummins engines, as will other truck manufacturers.
Navistar spokesman Roy Wiley expressed confidence in the company’s decision to avoid SCR.
“We said all along that we believe that we’re going with the solution that best fits commercial truck customers, which is EGR,” Wiley told TT. “EGR doesn’t have the extra weight of urea systems, and our customers won’t have to go looking for it.”
Cummins’ engineer Charlton said the company had begun talking with truck makers “to see how we can integrate our new powertrain into their vehicles.” He said Cummins is now testing 2010 SCR heavy engines.
Truck manufacturers said they were happy with Cummins’ decision.
“This decision by Cummins is good for the entire industry,” Robin Easton, Paccar’s treasurer, told Transport Topics. “Now, all the major OEMs will have the same aftertreatment system, and this further strengthens the viewpoint that SCR is good for fuel efficiency.”
Both Kenworth and Peterbilt trucks had been scheduled to offer Cummins engines in 2010. “There should be no change in that,” Easton said.
Michael Delaney, Daimler Trucks North America senior vice president of marketing, told TT, “We’re more convinced than ever that SCR presents the best possible emission and fuel efficiency solutions, and it sounds like Cummins is convinced of that at this point as well.”
Daimler’s Freightliner, Western Star and Sterling trucks will continue offering Cummins engines in 2010, Delaney said.
He added that Cummins’ decision “really isolates the anti-SCR crowd. There’s a very limited number of folks who think they can get to 2010 without SCR, and we wish them luck.”
Volvo Trucks North America, which recently signed a new agreement to continue offering Cummins engines after 2010, also welcomed Cummins’ move to SCR.
“Cummins’ decision is in line with what we’ve been maintaining all along, that SCR is the only viable way to meet the stringent EPA 2010 emissions regulations without sacrificing fuel economy,” VTNA spokesman James McNamara told TT.
Mack Trucks uses only its own engines.
Charlton denied that Cummins experienced any problems meeting 2010 mandates with EGR. He said Cummins would still use EGR engines but would be able to “dial it back a little” for greater efficiency, because much of the NOx would be removed in the aftertreatment instead of the original plan of inside the engine only.
Using SCR to remove NOx allows engines to run hotter, which means using less recirculated exhaust gases to cool combustion and allowing the engine to burn more efficiently.
Charlton said Cummins has experience with SCR technology. “This is not a new technology for us, because we’re running 200,000 SCR powertrains in Europe and have been preparing for U.S. midrange SCR for two or three years.”
