If Detroit Diesel Corp. (DDC) has its way, regeneration of the particulate filters for the 2007 engines will be unnoticeable, at least as far as drivers are concerned. In collaboration with Freightliner LLC, Detroit Diesel has been on an aggressive development and testing schedule for 2007, according to Tim Tindall, program director for the engine maker, and developing a procedure to manage the periodic regeneration of the required filter system has been a big part of that schedule.

DDC’s EPA 2007 efforts “are right on track for where we want to be,” he noted at a recent briefing. Since May of 2005, Tindall said that development team has logged more than 5-million test miles on Detroit Diesel’s Series 60 engine and exhaust aftertreatment system and expects to have more than 14.8-million total test miles on that engine by January 2007, including 6.7-million miles of customer fleet testing.

During all those test miles, DDC has learned plenty about managing regeneration timing, fuel “dosing” of the system, insulation solutions, and the safety measures required. For starters, notes Joe Grycko, a member of DDC’s Vehicle Performance Test Group and one of the people who has logged the most test miles on the new Series 60 engines and aftertreatment systems, regeneration is best done when the vehicle is underway, not stopped.

“If you are stopped during the regeneration process, we shut it down,” he says. “We also shut it down if the truck slows to below twenty miles per hour, and we don’t dose the system with fuel for the process if the compression brake is on.

“Regeneration typically takes about twenty minutes total and requires about a gallon of diesel,” Grycko notes. “The temperatures during regeneration are very high, which is why we want to control when it can take place and why insulation of the system is important. The injector that delivers fuel to the filter is water-cooled, for instance and, right now, it looks like our best choice for insulation of the system will be to go with a double-walled pipe.”

Riding in a test truck during the regeneration process, it was impossible to tell by vehicle performance, heat, sound or even smell that anything special was going on at all. Only the computer, added to the test trucks to display data concerning aftertreatment system functions, gave any clue. In production trucks, a red light on the dash will tell the driver that temperatures in the particulate filter are hot enough to accomplish the regeneration cycle. Otherwise, he or she might miss the whole event, too. An amber light will signal a problem with the system.

“There will be a little learning curve for drivers, of course,” says Grycko, “but we’ve all worked very hard to make the entire transition to the 2007 Series 60 engines as easy and painless as possible. We’re even considering a filter exchange program, for instance, so that drivers won’t have to wait during the physical removal and cleaning of the particulate filter that will be required about every 200,000 to 400,000 miles.”