How does a DPF Diesel Particulate Filter work?

Ever wondered what a DPF filter is and how it works? We explain the what it is and why you need to clean your DPF.

A Diesel Particulate Filter (DPF) is an exhaust aftertreatment device that significantly reduces emissions from diesel fueled vehicles and equipment. 

What happened before DPF's were available?

In the past, Diesel engines were known to emit high levels of particulate matter and nitrogen oxides (NOx), which are harmful pollutants that can cause respiratory problems and contribute to smog. Since the introduction of DPFs, diesel engines have become much cleaner. In fact, according to the Environmental Protection Agency (EPA), DPFs can reduce particulate matter emissions by up to 90%. The introduction of DPFs has also led to a significant reduction in nitrogen oxide emissions. 

How does a DPF work?

DPFs typically use a porous ceramic or cordierite substrate or metallic filter, to physically trap particulate matter and remove it from the exhaust stream. The Diesel Particulate Filter core contains porous walls of a ceramic honeycomb structure made of silicon carbide. The exhaust gases then enter into the channels that are open at the outlet end. Furthermore, the exhaust systems take away the exhaust gases. The DPF core retains the soot particles physically.  Once the DPF has captured the polluting soot, it stores it until the engine reaches a high enough operating temperature to burn the soot, converting it to less polluting ash. This process is called regeneration, and in DPF terms there is passive and active regeneration.

Why do i need to clean my DPF with a forced regeneration?

Most vehicles DPF system take care of themselves. But, to what extent depends on a number of factors, including your additives, how you drive, and more. We explain this in the article Why do i need to regenerate my DPF Filter?