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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.

To fullfill continually decreasing future emission standards, combined exhaust aftertreatment systems consisting of different catalyst technologies and particulate filter are necessary. Over the lifetime of such systems, catalytic performance of all individual components decreases due to thermal aging and poisoning effects. This has to be taken into account during system design as well as during the development of the operating and control strategies, to ensure long term system performance. Especially in commercial vehicle applications, this is an important issue because of long vehicle lifetimes in terms of mileage. In combined aftertreatment systems, the thermal histories of the catalytic components are linked and influence each other. Especially in systems containing a diesel particulate filter, thermal aging of all components is mainly dominated by the active DPF regeneration strategy for the filter.