Ash transport and deposition, cake formation and segregation – a modeling study on the impact of ash on particulate filter performance
The application of particulate filters has been state-of-the art in the exhaust gas aftertreatment of diesel engine emissions for many years. Similar, the application of wall flow particulate filters is a promising technology to fulfil the upcoming legislation limits of gasoline engines. Wall flow filters feature high filtration efficiencies at acceptable levels of pressure loss. The increased pressure loss due to particle matter (PM) accumulation is handled by removing combustible particles by active and passive regeneration measures. Non-combustible particles, commonly summarized as ash, remain in the filter and deteriorate its lifetime performance. Considering that during a filter’s useful life there is more ash in the filter than soot, ash plays an important role in the design and control of filter components. The contribution of this study is to bring ash modeling into a broader simulation context with the aim to investigate transient phenomena of coated filters.