Commentary: Keeping DPFs Clean

Two million is a big number. But that is how many Class 6 to 8 trucks will enter the aftermarket for emission control and aftertreatment components over the next six years, according to a recent report by Frost & Sullivan. Diesel particulate filters will account for most of the growth, the report says, rising from an estimated 14.4% of Class 6 to 8 emissions control and aftertreatment components revenue in 2014 to 40.1% in 2020.

From the fleet perspective, it looks like you are going to be spending quite a bit of money on your emissions control systems. However, there are ways you can minimize having to replace components — which is where the real cost is — with proper maintenance and cleaning.

Exhaust gas circulation valves and coolers and DPFs have been around since 2007. Yet not all fleets have a good understanding of the proper cleaning cycle, says Tom Bertolino, vice president of NorCal Kenworth, a Kenworth dealership headquartered in Sacramento, Calif.

“A lot of smaller fleets don ‘t know what their cycle should be for cleaning the DPF. It is based on the duty cycle of the engine and what they are doing with the truck,” he says. Trucks in over-the-road applications are going to get better duty cycles out of their DPFs than those operating in stop-and-go applications, Bertolino adds.

Joe Ward, owner of First Call Truck Parts, a distributor of medium- and heavy-duty truck parts, says, “Fleets need to get on a maintenance schedule with their DPFs, instead of running them until they quit.” But he agrees that finding the right maintenance schedule can be tricky. “If you have a garbage truck fleet, it might be every six months. If you operate over the road, it could be every two years.”

Manufacturers offer guidelines, says Joseph Kukuc, shop foreman at Diesel Service Center, an independent repair garage in Bolingbrook, Ill. “After looking at everybody’s recommendations, we narrowed it down to make it easier for our customers,” he says, including recommending the DPF be serviced every 200,000 miles in an a typical over-the-road application.

However, Ward believes it might not be that simple. “It really is just trial and error, figuring it out and learning on your own.”

One key conclusion of the Frost & Sullivan report is that “service intervals for DPF cleaning will decrease as fleets commit to periodic inspections to extend the life of the system and avoid costly replacement.”

How costly? Ward says, “When the DPF breaks it is at least $2,000 to replace it — that’s the starting price for the aftermarket.”

Kukuc concurs and adds, “The biggest reason for maintenance is the cost of replacing components that might be salvageable if the systems were serviced properly.” And he says replacement filters can cost as much as $3,100, not including the labor.

A basic maintenance service is not complicated and involves a visual inspection of the components and a flow test to see how much restriction is in the filter, Kukuc explains. If restriction levels exceed the baseline for that particular filter, the filter needs to be run through a pneumatic cleaning machine and then retested for flow.

Thermal cleanings are used when filters are badly plugged, which can happen when proper maintenance is not done or following an engine-related problem. It can take 12 hours for a thermal cleaning to be completed. Regular maintenance and pneumatic cleaning take much less time than thermal cleaning, so the truck will be back on the road more quickly.

A regular DPF maintenance program should, as Frost & Sullivan predicts, reduce the need to replace DPFs. According to Ward, when selecting a service provider for your DPF maintenance and cleaning, “experience is a big thing. Look for someone who has been doing it for a while. And check out their equipment; some equipment works better than other equipment.”