Representatives of three major truck and engine makers acknowledged at a recent meeting that diesel particulate filters are having unexpected performance problems.
The ceramic material used to produce DPFs has been cracking under the stress of operations, a defect that can generate the need for a new filter, some say. New filters can cost as much as $3,500.
The DPF issue was raised earlier this month during a session held at the fall meeting of the Technology & Maintenance Council of American Trucking Associations.
The scrap rate for DPF’s is “higher than we’d like,” said Mark Spaseff, a vice president of Mack Trucks and Volvo Trucks North America. He noted, however, that most of the work has been “warranty-related so far.”
Spaseff also mentioned the difficulty of the task involved.
“It’s mostly because this is a new technology. There was no baseline for what’s out there,” he said.
Vic Meloche, a manager for Detroit Diesel Corp., said the top reason for DPF failures was fluid surge. If a radiator or other component containing fluid fails, the liquid goes through the truck, including the DPF, which treats gases post-combustion. The second reason he mentioned was difficulty in engineering a solution for a very complicated problem.
“We’re gaining experience in operations and we’ve made modifications [for the newer DPFs]. We’ve tweaked our strategies,” he said.
As an example, Meloche said a 2010 DPF in a Detroit Diesel will have two ceramic substrates, whereas the 2007 models have just one.
Kevin Otto, a service director for Cummins Inc., said Cummins has studied the matter internally but declined further comment.
Speaking on the condition of anonymity, several maintenance managers expressed frustration about DPFs cracking early, with dissatisfaction spread among several manufacturers.
DPFs, which reduce the emission of diesel particulate matter, have been standard equipment on U.S. and Canadian trucks built since Jan. 1, 2007.