Diesel particulate filter

Along with Ultra Low Sulfur Diesel fuel (ULSD) or a ULSD/biodiesel blend, this component is largely responsible for clean diesel exhaust. A cell type structure inside the filter traps particulate matter (soot) and prevents it from being released with the exhaust gas. When the soot builds to the saturation point, the onboard computer puts the filter into an automatic regeneration mode in which the internal temperature is increased to a level that incinerates the soot particles. After regeneration is complete, the DPF is ready to go back into capture mode.