Parked forced regenerations of diesel particulate filters continue to frustrate and confuse drivers. Drivers under time constraints often tempt fate and continue their journeys, ignoring regen requests. A system derate or shutdown can sideline a truck for a couple of days if the DPF requires advanced service.

Newer post-2010 trucks are a little more forgiving in their warnings. 

“On older engines, before the advent of the SCR [selective catalytic reduction] system, drivers generally had three to four hours between the time the light came on and when you absolutely had to perform a regen,” says Scott Barraclough, Mack technology product manager. “Newer trucks offer at least eight hours from the time of the first alert and when it must be regen’d. That allows drivers to get through a shift or at least find a convenient time and place to park.”

The bad news is that there are still lots of older systems running around, and drivers need to be aware of different alerts and warnings on trucks of different makes, models and ages.

“Drivers need to be aware of the system on the truck and they must follow the prompts and instructions provided by the truck,” Barraclough says.

Trucks should be equipped with instructions outlining the parked regen procedures to avoid confusion.

While drivers can’t influence the vehicle’s duty cycle, they should be mindful of the impact of behaviors such as idling.

“Light loads and stop-and-go driving certainly play a factor in DPF regeneration performance, as additional soot is created during erratic duty cycles and/or stop-and-go traffic,” says Kurt Swihart, Kenworth marketing director. “This, along with lack of exhaust heat from light engine loads and extended idling periods, will cause a need for more frequent regens.”

As well, drivers should report any make-up coolant or oil they use. Since the visible smoke from burnt oil or coolant can no longer be seen, adding fluids indicates that oil and coolant are going somewhere.

“Oil and/or coolant consumption all play a factor with DPF contamination and will result in the engine controller commanding more frequent regenerations,” Swihart says.