Ever since 2007 all Dodge Cummins 6.7, Ford Powerstroke 6.4, and Chevy Duramax 6.6 trucks come from the factory equipped with a particulate filter to meet tougher emissions standards. A diesel particulate filter (DPF) is a device that traps the soot and unburnt fuel from diesel combustion. You might have noticed if you have one the 07+ diesel pickups that it never puts out any black smoke at all. The DPF will capture 90% or better of all harmful diesel emissions. Once the DPF has become “filled” of soot, it will need to have a regeneration cycle in order to burn all the soot out. You might have noticed a light on your dash from time to time that alerts you that the DPF is in regen or cleaning filter.
Essentially what is happening throughout this process is that the engine’s computer has been sure from the information that it receives from the sensors installed in the exhaust that the DPF has filled up past its suitable limit. The computer then opens the exhaust recirculation valve (EGR) introducing hot exhaust into the intake to help get exhaust gas temps top and also injects a small shot of fuel into the cylinders when the exhaust valves are open. The raised exhaust temps and the small amount of fuel then burn out the particulate that the DPF has collected since its last regeneration. Once the computer gets readings from the sensors in the exhaust that the filter is flow an acceptable limit again, it ends the regeneration cycle. The frequency of this cleaning cycle is different from vehicle to vehicle depending on use, mileage, and engine condition.
DPF is a device designed to take away diesel particulate matter or soot from the exhaust gas of a diesel engine. Wall-flow diesel particulate filters regularly take away 85% or more of the soot and below certain circumstances can reach soot removal efficiencies of close to 100%. Several filters are single-use, intended for disposal and replacement once full of accumulated ash. Others are designed to burn off the accumulated particulate either passively through the use of a catalyst or by active means such as a fuel burner which heats the filter to soot combustion temperatures; engine programming to run when the filter is filled in a manner that elevates exhaust temperature or produces high amounts of NOx to oxidize the accumulated ash, or through other methods. This is recognized as “filter regeneration”. Cleaning is also required as part of periodic maintenance and it has to be done carefully to avoid damaging the filter. breakdown of fuel injectors or turbochargers resulting in contamination of the filter with raw diesel or engine oil can also necessitate cleaning. The regeneration process occurs at road speeds top than can usually be attained on city streets; vehicles driven exclusively at low speeds in urban traffic can require periodic trips at higher speeds to clean out the DPF. If the driver ignores the warning light and waits too long to operate the vehicle above 40 miles per hour (64 km/h), the DPF may not regenerate properly, and continued operation past that point may spoil the DPF completely so it must be replaced
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