Experimental and 3D, embedded modeling for diesel engine SCR deposit
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Nowadays, the selective catalytic reduction (SCR) is a promising solution to fulfill stringent nitrogen oxide (NOX) emission standards enforced by worldwide regulation bodies for lean burning engines. However, in the practical operation, urea deposits occur under unfavorable conditions, which bring about a failure of urea dosing strategy, affect the SCR system de-NOx performance and lowering the fuel economy by increasing the engine back pressure. This paper will present 3D deposit model, which can be used to predict the deposit position. Furthermore, a model-based controls strategy and calibration are designed. The comparison test results of both engine emission tests and vehicle field tests shows there is significant deposits improvement with the embedded model.
Key WordsDiesel engine Urea-SCR Deposit 3D model Embedded model
selected catalyst reduction
32.5 % urea solution
dosing control unit
european transient cycle
universal gas constant
concentration of HCNO
film patch area
mass of deposits
mass of wallfilm with low temperature
urea mass fraction in the wallfilm
limitation of Miller curve.
mass of the injected Adblue
percentage of injected Adblue to wallfilm
the mass of evaporated water
urea mass which involved in themolysis reaction
the wallfilm volume
the wallfilm area
heat transfer coefficient.
wallfilm specific heat
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