LEHIGH VALLEY, Pa. – Mack Trucks, Inc. ramped up its evaluation of Selective Catalytic Reduction (SCR) as a possible solution to the future emission reduction targets that are facing the heavy-duty diesel engine industry. In September, the company introduced a Vision tractor equipped with an SCR system into its intra-company parts distribution fleet, based in Hagerstown, Md.

Putting the concept vehicle into regular over-the-road duty was the next major step in development said Stephen F. Homcha, executive vice president – Class 8 programs.

“We have been extremely pleased with the results that have been generated so far,” he said. “Our joint evaluation team – composed of individuals from Mack and Siemens Westinghouse Power Corp. – has been able to cut transient emissions of nitrogen oxides (NOx) by up to 70 per cent and particulate matter by up to 25 per cent. Steady-state emissions of NOx have dropped by up to 85 per cent.”

The process involves metering a low-cost solution of liquid urea into the exhaust stream prior to its entering a catalyst. n