Question: what is the difference between a diesel oxidation catalyst and a diesel particulate filter?
Answer: It is a flow through filter that contains precious metals to start the oxidation of hydrocarbons, carbon monoxide and unburned fuel and oil. Both the DOC and the DPF are honeycomb ceramic filters. However, unlike the DOC, the DPF is a wall-flow filter that traps any remaining soot that the DOC couldn't oxidize.