Urea for preventing nozzle clogging systematic approach scr
A method for preventing species urea SCR system nozzle clogging. Method for the urea selective catalytic reduction (SCR) system operation to prevent auto ignition operation of urea nozzle clogging, which is stored in the urea tank by the supply module, and a nozzle connected to said urea supply module and the urea a nozzle for supplying urea and the line, the method may comprise: an evacuation step and the pressure equalization step, the evacuation step, by generating a negative pressure in the supply module and will be returned to the urea in the urea tank; the the pressure equalization step, and the supply pressure is restored by stopping module generating a negative pressure in the supply module, wherein, in said step of pressure equalization, starting from the pressure equalization step on after a predetermined time pressure force controlling whether the injection of urea.