Canister/Shell

The canister or shell in a Diesel Oxidation Catalyst (DOC) is a cylindrical or oval-shaped metal enclosure designed to house the ceramic or metallic catalyst substrate. It serves as a structural container that withstands high exhaust temperatures (typically up to 700°C), pressure fluctuations, and mechanical stresses while ensuring proper exhaust gas distribution across the catalyst surface. The shell provides thermal insulation, prevents catalyst damage from external impacts, and maintains the integrity of the exhaust system by sealing against gas leaks.

The canister/shell operates by containing the DOC's catalyst substrate within a sealed, insulated environment. Exhaust gases enter through an inlet, flow through the substrate where oxidation reactions occur, and exit through an outlet. The shell's design ensures uniform gas distribution, minimizes thermal losses, and withstands thermal expansion/contraction cycles. It also provides mounting points for integration into the exhaust system and may include heat shields or insulation layers to protect surrounding components.