MORE A BUMP THAN BUST

Most industry experts, however, contend that the EPA's moves are in no way a death knell for Cummins' SCR package and do not herald the unraveling of the 2010 emissions deadlines.

“This is a new generation of SCR technology. While it's been in use in Europe for some time, it's being tweaked for U.S. trucking applications, so there are bound to be some bumps in the road,” explains Allen Schaeffer, executive director of the Diesel Technology Forum (DTF). “This is just one of those bumps. We're bound to find some issues because a lot of new components are being deployed for 2010.”

Cummins initially didn't plan on using SCR for its heavy-duty truck engine family — until the full potential for copper zeolite as a catalyst came into focus. According to Steve Charlton, vp of heavy-duty engineering for Cummins, although copper zeolite has been around for a long time, it wasn't in research labs until roughly three years ago and only became available for automotive applications in 2007.

“Copper zeolite is very, very efficient at reducing NOx compared to other catalysts,” notes Charlton, adding that its use within SCR should allow Cummins' 2010 engines to achieve up to a 5% improvement in fuel economy while meeting the EPA regulations.

Charlton also stresses that although everyone in the industry will be using EGR, all the engine OEMs except for Navistar plan to use EGR in combination with SCR to achieve lower emissions and better fuel economy simultaneously. “It's really the combination of EGR and SCR that makes this work, along with the diesel particulate filter [DPF],” he says.

Tina Vujovich, vp-marketing and environmental policy for Cummins, adds that the EPA's concerns are overblown. “Based on what we've seen so far, we don't have any concern about dioxins,” she explains.

Because of copper zeolite's benefits, Vujovich believes Cummins should have no problem passing EPA's inspections. “EPA is not in the business of shutting down manufacturers,” she says. “If they thought [copper zeolite] was a showstopper, they would have already told us. We feel very confident in the work we've done, and it's in their best interest and our best interest to get this approved.”

Other engine OEMs using SCR but not copper zeolite as a catalyst note that they don't believe the EPA is taking a negative view of SCR technology as a whole — far from it.

“We're getting no such reading from the EPA,” says David McKenna, Mack Truck's powertrain marketing manager. “Our understanding is that their concerns have to do with the high-temperature catalytic performance of copper-coated zeolite material and the voluntary withdrawal of such catalysts in Japan. We use an iron-coated zeolite system [and] there's no appreciable difference in the NOx reduction efficiency rate — 99% with copper and 98% with iron — [plus] nothing hazardous associated with our approach.”

“You've got to remember, too, that if the EPA had any doubts about SCR, they could just look across the pond at Europe; they can see years of SCR experience over there,” notes DTF's Schaeffer. “Also, according to the rules, the EPA needs to give the OEMs both lead time to develop new technology to meet the emissions requirements and then a period of regulatory ‘stability.’ They can't have a moving emissions target every couple of years. More importantly, they must give OEMs lead time to develop technology to meet the required emissions levels.”