May 1, 2008 12:00 PM

Johnson Matthey's latest diesel emissions technology, the SCRT system, has demonstrated in a trial, using a fleet of 16 older trucks owned by a Northern California grocery store chain, that it is possible that older can be cleaner.

Results were released recently of a demonstration using a number of older Class 8 grocery trucks retrofitted with Johnson Matthey's new SCRT four-way control system. Working with partner Cummins Emissions Solutions, Johnson Matthey tested its emissions system for more than 1,000 hours as the trucks traveled throughout Northern California hauling grocery products to Raley's family of grocery stores.

The demonstration program involved a local partnership among Raley's, the Sacramento Metropolitan Air Quality Management District (SMAQMD), and the Sacramento Emergency Clean Air and Transportation program (SECAT).

The four-way SCRT exhaust emission control system combines Johnson Matthey's patented two-stage CRT particulate filter system (to reduce particulate matter by more than 85%) with a selective catalytic reduction (SCR) catalyst that reduces nitrogen oxides (NOx) between 60% to 80%. It also reduces carbon monoxide and hydrocarbons by more than 90 percent. The result is a four-year-old truck with NOx emissions lower than those of a brand-new 2008 truck.

The findings of the 1,000-hour test were that the SCRT system reduced NOx in Raley's trucks by an average of 84 percent compared with pre-retrofit levels. The trucks involved had 2004 Cummins, 400-horsepower ISM engines with an EGR (exhaust gas recirculation) system. The ISM is a commonly used engine in Class 8 trucks hauling heavy loads.

The next stage for this technology is verification by the California Air Resources Board and the United States Environmental Protection Agency.

Johnson Matthey has nearly 50 demonstration units running in California and Texas. After thousands of hours of operation, the SCRT system retrofits on both EGR and non-EGR engines have reduced NOx emissions by as much as 84%.