Hitting the road
Hitting the road
Feedback on the latest heavy-duty power plants shows some positive signs as new technology tackles 2010 emissions standards.
By John Baxter
Selective catalytic reduction, used by all but one heavy-duty engine manufacturer to meet the 2010 emissions standards, opened up a whole new area of technology and maintenance.
SCR is a diesel designer’s dream. It kills oxides of nitrogen outside the engine, which allows for lower levels of exhaust gas recirculation, reducing engine stress. Because the additional NOx in the exhaust eats up soot, it means less regeneration of the soot collected in the diesel particulate filter.
Still, an additional system on the truck adds cost, weight and the responsibility for the driver to refill a diesel exhaust fluid tank so the SCR system can work. These facts are constantly stressed by Navistar, which has taken the bold step of meeting the new standards with a combination of basic engine technology changes, including higher levels of EGR, and applying emissions credits the company has with the U.S. Environmental Protection Agency.
Following is a look at early reports on the new engines from manufacturers and their customers.
Customers with Detroit Diesel’s 2010 engines are getting a net 3 percent improvement in fuel cost, says Amanda Phillips, director of component marketing and communications for Daimler Trucks North America. The new engines actually average a 5 percent improvement, but fleets typically spend 2 percent of what their fuel bill is on DEF. The net difference in cost could improve, she says, because “diesel fuel will go up, while DEF is not likely to.”
She says the 2010 Detroit Diesel engines idle more quietly than previous designs. At the same time, 2010 versions of the engine are more fuel efficient than earlier ones mainly because the DPF needs active regeneration only at about 3,000 miles, versus 300 for 2009-spec engines.
Mike Hasinec, vice president of maintenance systems and support for Penske Truck Leasing, says customers have seen miles per gallon improve 3 percent to 7 percent in Penske’s Freightliner Cascadias and medium-duty trucks running 2010 engines. “And there have been no maintenance issues. The percentage of DEF required has ranged from 1.5 to 3 percent of fuel usage. As the DEF does not cost too much, our customers have seen an improvement in their bottom line.”
Oil analysis reports have shown no major changes, Hasinec says.
“The drivers like the throttle response, and have seen less need for forced manual regenerations,” he says.
The 50,000-mile oil change interval that is standard with the DD15 and its sister engines because of finer filtration will remain, says Phillips. “We are seeing positive results and have no concern that we need to adopt earlier changes.”
Matt Hein, co-owner of Tri-Hi Transportation, running DD15 engines in Freightliner Cascadias, sees on-road DPF regenerations occurring at 2,500-3,000 miles versus 400 on 2007 equipment. He has figured fuel economy gains and subtracted DEF costs, and sees a net reduction in cost of $4,500 to $5,000 per truck per year.
Daniel Scherer, fleet maintenance manager at Meijer, Inc. says his Cascadias equipped with DD13s are delivering about 12 percent better fuel economy than the trucks they replaced.
Steve Duley, vice president of purchasing at Schneider National, says its Cascadias powered by the 2010 DD15 have accumulated 500,000 miles, with more than 200,000 on one, without maintenance issues. Fuel economy beats that of their trucks with earlier engine technologies.