Diesel Particulate Filters, a Hot Subject.

In January 2007, the new emission law went into effect for diesels. Of course the new diesel engines designed for lower emissions cost more, have EGR coolers, throttles, use more expensive CJ4 low ash classification engine oil and have a Diesel Particulate Filter. The DPF is where pollutants are trapped and burned off when it regenerates. With the new ultra low sulfur diesels, Ford 6.4L, Dodge 6.7L and GM 6.6L LMM,  their Diesel Particulate Filter can get to 1100 degrees F when it's regenerating (burning up the noxious oxide.) If the DPF is almost full, it can take up to 30 minutes to burn out as your drive. If you remember when catalytic converters first came out, we had many wheat field and grass fires. Look at the tailpipe on these new diesels, some look like a propane weed burner, but are designed for cooling the exhaust where it leaves the truck.

As you run your diesel, sensors in the DPF measure the amount of particulate matter that is accumulating in the filter and send that data to the engine computer that controls the engine and aftertreatment process. When DPF sensors tell the engine computer that the DPF is filling up, a self-cleaning process called regeneration will raise the temperature in the DPF by turning on an injector during the exhaust stroke to oxidizes the particulate matter.

In some trucks you can smell the DPF regeneration and feel some power gain when finished. Under normal operating conditions, you don’t need to do anything. If you do a lot of city driving or hours of idling, your engine may not be working hard enough to regenerate. This can cause warning lights to let you know, your truck needs highway time to clean the DPF. If you drive after the warning lights come on too long the DPF gets too full, you will loose power and damage the expensive filter. Read your owners manual this time.

There are aftermarket engine programmers on the market now such as Superchips that will force the engine to regenerate when you want to, like before that 15 mile grade on I-70 in Utah or the sled pull at the county fair. Next emissions hurdle for diesels is 2010. The 6.7L Dodge Cummins diesel is the only engine of the big three that is already compliant for the stricter 2010 requirement. That next hurdle in 2010 EPA diesel rules, have most truck manufactures going with Urea (exhaust fluid) to lower emissions. I’d like to see them add CNG . Looks like International (Navistar) which could include Ford Power Stroke diesels will go another route, with larger EGR (exhaust gas recirculated) instead of Urea.