A DPF is designed to collect the soot that is created when diesel is burned, preventing harmful particles from being pumped out into the atmosphere. All post-2009 diesel cars that comply with A diesel particulate filter (DPF) is a filtration device installed in a diesel vehicle's exhaust system to trap particulate matter such as soot and ash, which are present in diesel A diesel particulate filter (DPF) is a filter fitted to cars and it is made to capture and store exhaust soot. The soot is a naturally occurring part of the combustion process, but larger pieces can be dangerous for an engine, so the filter removes this risk. Diesel Particulate Filters, also known as DPFs, are exhaust . aftertreatment devices that significantly reduce emissions from diesel fueled vehicles and equipment. DPFs typically use a porous ceramic or cordierite substrate or metallic filter, to physically trap particulate matter (PM) and remove it from the exhaust stream. a9gcR.