METHOD FOR PREVENTING CLOGGING OF UREA INJECTION NOZZLE OF SCR SYSTEM

摘要

In a method for preventing clogging of a urea injection nozzle in an after-run operation of a selective catalytic reduction (SCR) system which supplies urea stored in a urea tank through a supply module, a urea injection nozzle and a urea line connecting the supply module and the urea injection nozzle, the method may include an emptying step where the urea is withdrawn into the urea tank by creating negative pressure in the supply module and a pressure equilibrium step where the pressure in the supply module is recovered by stopping creation of negative pressure in the supply module, wherein in the pressure equilibrium step, whether to forcibly inject the urea is controlled on the basis of pressure after a predetermined time has passed since the pressure equilibrium step began.