VERFAHREN ZUR STEUERUNG DER MENGE VON HARNSTOFFKRISTALLEN IN EINER ABGASLEITUNG EINES VERBRENNUNGSMOTORS MIT EINEM SCR-KATALYSATOR

摘要

The invention relates to a method for controlling the quantity of urea crystals present in an exhaust line comprising a catalytic converter for the selective catalytic reduction of nitrous oxides (NOx), referred to as SCR, by means of a reducing agent, said method comprising a step of heating the exhaust line to a sufficient temperature to sublime the urea crystals, this step being triggered periodically on the basis of a computational model and being accompanied by measurements of the quantity of nitrous oxides and/or the quantity of reducing agent at the inlet and outlet of the catalytic converter, then a step of calculating the quantity of urea crystals (MCm) present in the exhaust line on the basis of the measurements taken at the heating stage, then a step of adjusting the computational model on the basis of the quantity of urea crystals calculated in the calculation step. The invention also relates to an engine unit comprising an electronic control unit that implements the control method. Finally, the invention relates to a motor vehicle comprising the engine unit.