While every other engine maker adopted SCR systems to meet stringent new NOx reduction rules for 2010, Navistar decided to continue with EGR-based engine technology.
Navistar had asked the U.S. Court of Appeals in Washington, D.C. to void the U.S. Environmental Protection Agency’s certification polices for SCR-equipped trucks because they had been adopted by the EPA without the public process required by law, but instead following input only from the SCR engine makers.
Navistar also contested that when SCR engines operated without diesel exhaust fluid (DEF), which they can for a set period of time, the engines do not meet the NOx emission requirements.
“Navistar first identified these loopholes to the agencies and also presented our concerns at today’s workshop,” said Jack Allen, president of Navistar’s North American truck group. “We will be working with the EPA and CARB to ensure full environmental compliance.”
At a joint workshop on July 20 hosted by the California Air Resources Board (CARB) and EPA, Navistar presented their concerns about environmental compliance and used independent test findings to reiterate their point.
Navistar commissioned EnSIGHT, an independent environmental consulting firm, who then researched two long-haul vehicles and one heavy-duty pickup using SCR technology and found that the vehicles throw off levels of NOx as much as 10 times higher when DEF is not present.
During EnSIGHT’s research the vehicles tested showed no change in operation when the DEF tank was empty or refilled with water. One of the trucks tested, according to Navistar, accumulated more than 13,000 miles with water in the DEF tank.
Navistar is now calling on the EPA and CARB to eliminate the loopholes and the resulting excessive NOx emissions.
“Truck owners are paying a substantial price to comply with 2010 NOx requirements,” said Allen. “They, and the public, deserve to know that the new equipment they are purchasing actually works as promised to curb pollution.
“It’s obvious, however, that these trucks can operate effectively without liquid urea, and that under these and other conditions, SCR NOx emission control is turned off. We’re calling on the EPA and CARB to assure that all vehicles, not just ours, work when they are supposed to be working.”