A Diesel Particulate Filter, sometimes called a DPF, is device designed to remove Diesel Particulate Matter or soot from the exhaust gas of a Diesel engine, most of which are rated at 85% efficiency, but often attaining efficiencies of over 90%. A Diesel-powered vehicle with a filter installed will emit no visible smoke from its exhaust pipe.
In addition to collecting the particulate, a method must be designed
to get rid of it. Some filters are single use (disposable), while
others are designed to burn off the accumulated particulate, either
through the use of a catalyst (passive), or through an active
technology, such as a fuel burner which heats the filter to soot
combustion temperatures, or through engine modifications (the engine is
set to run a certain specific way when the filter load reachs a
pre-determined level, either to heat the exhaust gasses, or to produce
high amounts of No2, which will oxidize the particualte at relatively
low temperatures). This procedure is known as 'filter regeneration.'
Fuel sulfur interferes many 'Regeneration' strategies, and all
jurisdictions that are interested in reduction of particulate
emissions, are also passing regulations governing fuel sulfur levels.
