Investigations on Chemical Ageing of Diesel Oxidation Catalysts and Coated Diesel Particulate Filters
For medium- and heavy-duty diesel engines, the development of new catalyst technologies and particulate filters is necessary to fulfill increasingly stringent emission regulations. An important aspect is the durability of the after-treatment system and therefore its efficiency over lifetime. Lubrication oil additives contain components such as phosphorous or zinc to ensure engine durability. Diesel oxidation catalyst (DOC) and coated diesel particulate filter (cDPF) catalytic coatings are negatively influenced by contamination on the surface with these components (chemical ageing). The components have a negative impact on the exhaust after-treatment systems performance. Additionally the cDPF is filled with oil ash. Engine tests are conducted to analyze the effect of lubrication oil additives on after-treatment system performance. In one study, lubrication oil with increased sulfur ash content is used.