Reduced-emissions combustion utilizing multiple-component metallic combustion catalyst and lightly catalyzed diesel oxidation catalyst

摘要

An improved diesel operation system employs a lightly diesel oxidation catalyst (DOC), preferably with a platinum containing fuel borne catalyst (FBC) in the fuel. The DOC is at least partially lightly catalyzed with precious metal catalyst, e.g., platinum group metal, having a metal loading of from about 3 to 15 grams per cubic foot to minimize formation of NO₂ in the exhaust gas. Preferred fuel borne catalyst levels will be low, e.g., from 0.05 to 0.5 ppm for platinum and 3 to 8 ppm for cerium and/or iron, thereby providing effective engine out emissions reductions without discharging excessive amounts of metal catalysts or NO₂ to the atmosphere.