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11/24/2009 8:00:00 AM
E&MU: Next-Gen Diesels Cut DPF Upkeep, Engine Makers Say
By Frederick Kiel, Staff Reporter
This story appears in the November/December 2009 issue of Equipment & Maintenance Update, a supplement to the Nov. 23 print edition of Transport Topics. Click here to subscribe today.
The ire of fleet managers who say diesel particulate filters are clogging with soot too quickly should be eased with the arrival of 2010 engines, according to some engine manufacturers.
In meeting the final reduction of nitrogen oxide emissions, the coming generation of diesel engines will produce less particulate matter, in turn putting re-duced burden on the filters, said David McKenna, director of powertrain marketing for Volvo Trucks North America.
“We’re making simple chemistry work in our favor,” he said, explaining that the chemical reactions taking place in Volvo’s selective catalytic reduction engines will eliminate more soot than current engines, thus sending cleaner exhaust through the DPF.
Volvo is one of several manufacturers using SCR to meet the Environmental Protection Agency’s 2010 NOx limits, and Volvo’s approach to the technology is largely mirrored by the others.
m/search/frmSearchTop.aspx?terms=Navistar">Navistar, by contrast, is sticking with exhaust gas recirculation to hit the new target, and expects its 2010 engines “not [to] have appreciably greater soot” than current units, said Timothy Shick, director of marketing for the company’s engine group.
All diesel manufacturers began equipping commercial trucks with DPFs in 2007 to remove particulate matter from the exhaust stream. These filters trap and break down unburned solid particles. Eventually, the accumulated matter is consumed by the systems’ heat. Regeneration leaves no residue in the filter.
In general, DPF systems function passively. Engines running at highway speeds over extended periods generally produce enough heat, combined with the chemical reaction caused by the filter’s precious metal catalyst, to convert contaminants to carbon dioxide gas. The operator does not have to take any action to prevent soot buildup in the filter’s chambers.
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