What is in Car Exhaust? | Exhaust Components: Criteria Pollutants and Greenhouse Gases | Corning

Diesel Particulate Filters

Diesel Particulate Filters

Diesel Particulate Filters

What is a Diesel Particulate Filter (DPF) System?

What is a Diesel Particulate Filter (DPF) System?

While flow-through substrates are ideal to support catalytic activity and eliminate harmful gaseous pollutants, they are not focused on reducing particulates from exhaust. Particulates are usually the result of incompletely combusted fuel. In diesel vehicles, that is where Corning’s diesel particulate filters (DPF), come into play, first developed in the 1980s.

For diesel particulate filters, individual channels are open at one end and plugged at the other, creating a checkerboard face design.  Exhaust enters the open (inlet) channels, flows down toward the blocked, or plugged channel ending at the other side. The pressure forces the exhaust to flow through the engineered, porous walls of the ceramic channels. The filter traps the particulates on the filter walls, leaving cleaner air to exit the filter from the adjoining (outlet) channels and out of the tailpipe. These filters can withstand high temperatures >1100°C (2000°F), are extremely thermal shock resistant (to survive that rapid heat-up on frigid mornings). 

Many filters on a vehicle, like fuel filter or air filters, must be replaced when they reach their dirt-holding capacity. However, DPFs are unique in that they are periodically cleaned while on the vehicle. The captured particles remain in the filter and the combustible portion of the particulates are periodically burned off through a regeneration process. This regeneration process can be passive (part of the natural drive cycle) or active (initiated by the engine controls). The incombustible portion of the particles, which remains in the filter, is known as ash. For heavy-duty, high mileage vehicles, this ash can build up over time and can be removed from the filter only if the filter is removed from the vehicle for cleaning.

Diesel particulate filters are a standard component for today’s diesel aftertreatment systems in passenger and heavy-duty systems. Corning offers a range of cordierite and aluminum titanate DPFs for cars, trucks as well as non-road applications like construction and agricultural vehicles.

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