September 2, 2014
DPF cleaning is necessary to keep heavy-duty trucks on the road, and believe it or not, it’s not a dirty job.
Most DPFs in use in today can be cleaned in an hour or less. The process is predominately automated, and there is a lot of DPF cleaning equipment on the market.
Effectively cleaning a DPF and its associated parts during preventive maintenance (PM) stops increases the life of the filter, keeps the engine running smooth and minimizes future breakdown risks.
Most heavy-duty DPFs require cleaning every 200,000 to 250,000 miles.
The first step in cleaning a DPF is to inspect the filter housing and its related parts for wear or damage, says FSX Inc., a heavy-duty DPF cleaning services company.
A well-kept DPF can last through several cleanings but a DPF must operate at 100 percent to be effective. David McNeill, parts and service manager at Cummins Emissions Solutions, says a DPF should be “inspected and verified suitable for re-use” before cleaning.
Any DPF found to operating incorrectly should be replaced.
After a DPF passes visual inspection it can be removed from a tractor and attached to a filter cleaner to begin the process of removing soot and dirt from its interior.
Each OE recommends different cleaning tools during this step.
Paccar advises its filters be cleaned using FSX’s tool, which requires the filter be removed from the tractor and placed into the machine for cleaning.
Karl Mowat, general marketing manager at Paccar Parts, says using proper technique is a must.
“Inadequate cleaning and maintenance of the DPF can lead to more frequent system regenerations, which may lead to shortened life of the DPF as well as the after treatment system as a whole,” adds McNeill.
Once a technician knows what cleaning system the DPF requires, he must simply affix the DPF to the cleaning apparatus and start the process.
A common method for DPF cleaning is to direct air at high-pressure through the DPF in a circular, knife-like snaking motion to dislodge the particulate from the walls of the filter and out through the end.
This process knocks the ash and soot from the DPF quickly and efficiently, Mowat says. The particulate is then deposited it in a separate container easy disposal.
While a DPF is being cleaned a technician also should check its related components.
John Moore, powertrain product manager at Volvo Trucks, says a diesel exhaust fluid pump filter and tank filling arm both have recommended service intervals shorter than a DPF, advises technicians to check and clean both pieces during a DPF cleaning.
The next step after a cleaner completes its cycle is to check the DPF internally to make sure the cleaning was successful.
The FSX cleaner Paccar recommends includes an air flow test that “tests a filter before and after it’s cleaned to determine backpressure from ash build-up,” says Mowat.
A DPF that passes should be re-installed on a truck, while a failing test means the DPF must be re-cleaned in the machine or through thermal cleaning, he says.
Thermal cleaning works by placing a DPF in a heat chamber at an elevated temperature that eventually loosens and removes excess particulate encased on the walls of the component. Also known as “baking” the filter, thermal cleaning is used after unsuccessful on-site cleanings.
To assure all Volvo trucks return to the road with a peak-operating DPF, Moore says Volvo offers their dealers a program to purchase their own FSX DPF cleaning system. They also offer a clean and return program that allows dealers to send their customers’ DPF filters to the Volvo remanufacturing facility for inspection and cleaning. Volvo customers can also elect to purchase a new filter.
Cummins operates a similar program where filters are exchanged, and McNeill says customers receive a component “that meets the condition and performance specs of the original Cummins DPF.”
A typical DPF swap averages 30 minutes, while McNeill says a DPF removal, cleaning and re-attachment can be done in hour or less.