The California Air Resources Board (CARB) held a public workshop yesterday to discuss possible changes in the way selective catalytic reduction (SCR) systems react to malfunctions or other problems in trucks meeting the Environmental Protection Agency 2010 diesel engine emissions standards. The workshop was part of an agreement with Navistar International (NYSE: NAV). that led to its withdrawal of lawsuits against EPA and CARB over “guidance” or shutdown strategies issued by EPA for trucks using SCR. Navistar is the only U.S. truck manufacturer that has chosen not to use the SCR technology to meet the new emissions rules, instead employing what it calls “Advanced EGR.”
In the public notice announcing the workshop, CARB pointed out that it had already “approved 2010 and 2011 model year heavy-duty diesel engines with SCR… However, for future vehicles seeking certification, [CARB] expects manufacturers to do a better job of assuring that vehicles are not allowed to operate out of compliance for significant periods of time.”
With the EPA also in attendance, Navistar presented test data that showed three trucks with SCR systems were able “to operate effectively” without the diesel emissions fluid (DEF) needed to control the regulated NOx emissions, increasing NOx emissions “ as much as 10 times higher or more than when [DEF] is present.” The test was conducted with two long-haul tractors and a heavy-duty pickup by EnSIGHT, an independent consulting firm hired by Navistar.
“One truck tested appears to operate indefinitely with water and as a result without any functioning SCR NOx control,” according to a news release from Navistar issued after the workshop. “That truck has accumulated more than 13,000 miles with its SCR NOx emission control turned off.”
“Truck owners are paying a substantial price to comply with 2010 NOx requirements,” said Jack Allen, president of Navistar’s North American Truck Group in his presentation to the workshop. “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 [DEF], 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.”