Diesel particulate filter

A diesel particulate filter (DPF) helps your car get rid of filthy sooty exhaust. It's like a sieve that traps tiny particles of soot and other pollutants so they don't get out of the exhaust and into the air. The DPF works like this: As your car is running, it sends exhaust gases through a filter made of many tiny little honeycomb walls. These walls have lots of tiny holes in them. As the smoky exhaust passes through, the soot particles are caught in the tiny holes. Clean air then passes through and comes out the back, leaving the soot and other pollutants trapped inside. The DPF can eventually get clogged up with soot, and then it needs to be cleaned out (called a “regeneration”).