Mathematical model of the thermal regeneration of a wall-flow monolith diesel particulate filter

Abstract A wall-flow monolith filter placed in the exhaust stream of a diesel engine can effectively limit the emission of diesel particles through the monolith. The accumulated particles can then be periodically combusted inside the monolith by directing hot gas from a fuel burner to the monolith while the normal engine exhaust is routed around the burner/monolith system. The resulting low flow rates through the monolith require consideration of gas dynamics through the channels as well as particle combustion to analyze this regeneration process. A mathematical model of the regeneration is formulated as a system of nonlinear partial differential equations describing the conservation of mass, momentum and energy. Numerical solutions are obtained by using a combination of finite element and finite difference techniques for the spatial discretization and using an implicit ordinary differential equation solver for the resulting time integration. A detailed discussion of the solution for a sample regeneration is given.