Volvo Trucks North America (VTNA) and Mack Trucks, both companies of the Volvo Group, will use selective catalytic reduction (SCR) to meet EPA's 2010 diesel engine emissions standards.
SCR is an aftertreatment technology that involves injecting a water-based solution containing urea into the hot exhaust stream of an engine.
The urea, in conjunction with a catalyst in the exhaust aftertreatment system, breaks down the NOx into nitrogen and water vapor.
According to VTNA, urea is an organic nitrogen-containing compound commonly used in agriculture as a fertilizer and is classified by EPA as a nonhazardous substance.
Volvo and Mack both said they will also draw upon the Volvo Group's extensive experience with SCR in Europe, where it is used to meet the Euro 4 emissions regulations.
In the U.S., Mack and Volvo have had field tests of SCR-equipped trucks in operation since 2000 and 2003, respectively.
“Our experience indicates that vehicles utilizing SCR can achieve better fuel economy than those using only EGR for NOx control, while at the same time meeting the dramatically lower emission standards coming in 2010,” Mack president & CEO Paul Vikner said.