Pre-filter Diesel Oxidation Catalyst Development for DOC-CSF System

Pre-filter diesel oxidation catalyst (DOC) development for a DOC-CSF system has been conducted. The pre-filter DOC is required to efficiently oxidize fuel and generate heat to regenerate accumulated soot within the catalyzed soot filter (CSF). Therefore, high thermal durability is required. In addition, good transient hydrocarbon (HC) activity is required for the DOC to reduce tailpipe HC emissions. The required performance is dependent on the OEM's system control strategy.

A DOC catalyst designed to have well dispersed Pt showed high fuel combustion performance. Such high Pt dispersion was obtained by using high specific surface area Al₂O₃. Zeolite included into the catalyst formulation showed higher transient HC performance compared to a catalyst without zeolite. The effective catalyst layer depth with respect to transient HC activity was studied by computer simulation.