The 2010 technology trucks generally offer longer run times between DPF cleaning than the 2007 technology trucks. “For 2007 to 2009 engines, the ‘standard’ cleaning interval is approximately 300,000 miles, but this varies between engine families and by application,” says Williamson. “Engines built in 2010 and later raised the cleaning intervals to 300,000 to 400,000 miles, but again this generally depends on application and fuel consumption.”
No matter what the recommended interval, don’t ignore this vital pollution control device. If maintenance is not performed, the collected ash and soot can completely plug and destroy the DPF filter. This ceramic filter can cost $3,000 or more to replace.
“Yes, they are expensive, so handle with care,” cautions McKenna. “Do not drop or force the DPF element into the canister. You will end up with a very expensive piece of ugly ceramic art!”
Make sure the technicians who work on the DPF know what they are doing. “Follow proper operating and maintenance procedures outlined by the manufacturer and take it to a reputable shop for cleaning,” says Moore. “DPF substrates can be easily damaged if dropped during the cleaning process.”
If left untended, the DPF can create several issues. “Some of the consequences include the potential for being non-compliant with emissions regulations; cracking of the DPF; increased backpressure in the engine; the loss of power due to down rating; and potentially being down rated to a degree that will not allow the truck to perform at a level necessary to complete the job,” says Williamson.
Many vehicles will alert when the DPF needs to be cleaned via a backpressure monitor that lights up on the dash.
Take steps to reduce ash generation
Many variables can influence how fast the DPF fills with ash. These include factors such as oil consumption; not consuming oil at a rate greater than specified by the engine manufacturer; not using fuel or oil additives; avoiding long idle times; avoiding excessive start and stop driving conditions; and ensuring that you are using the appropriate CJ-4 oil.
Even oil change intervals may indirectly impact soot generation. “Fresh oil is much less likely to burn, but the same oil with 40,000 miles on it will,” says McKenna. “The oil control ring design is so good that most modern engines burn very little lube oil. However, when the oil wears out, it will get past the rings and burn off. The minerals that are in the oil are then collected in the DPF, adding more and unnecessary ash. I’m a firm believer that a regular factory approved oil interval is a very cheap insurance policy.”
“Reducing idle time definitely helps,” adds Williamson. “The cleaning intervals are not significantly reduced, because the cleaning of ash is based on the fuel used. The need for regenerations is affected by the time idling, the time driving, the temperatures, etc.”
Any reduction in fuel consumption also helps. “Soot is created during the combustion of diesel fuel, so any way that you can reduce fuel consumption will have a positive impact on ash cleaning intervals,” McKenna indicates.
This includes ensuring proper operation of the fuel injection system. “If there are issues with the fuel system (any component) that cause increased fuel consumption, then the cleaning interval will be decreased,” says Williamson.
According to McKenna, “This would probably have the biggest impact on DPF life short of a major turbo failure. A poorly maintained injector does not atomize the fuel effectively, and that would cause significant amounts of soot from poorly combusted fuel.”
SCR requires little maintenance
SCR systems were added starting with 2010 model trucks. The use of SCR systems has extended DPF cleaning intervals.
“With EPA 2010, thanks to the addition of Mack ClearTech SCR, we’ve been able to dial the EGR flow rate back to something resembling the 2004 profile,” says McKenna. “The benefit of reduced EGR flow is the engine can breathe better and the combustion is much, much cleaner, meaning we create much less soot... than we did with previous [engine] models. Less soot production means less need for DPF regeneration, virtually eliminating the need for active DPF regeneration. This also saves a lot of fuel. Less soot production also means less collected ash, so we are thinking another 150,000 miles or more to a DPF element cleaning than for pre-ClearTech engines.”