Patent ID: 8079209
Filing Date: 2011-12-20
Classification: B01D,F01N,F02N,Y02A,Y02T

Abstract:
1. A method for controlling a urea-SCR system comprising: a first step of calculating a target urea injection amount; a second step of using urea injection pressure and urea injection time to calculate a real urea injection amount; a third step of calculating a difference value between the target urea injection amount and the real urea injection amount, and monitoring the difference value at a predetermined time interval; a fourth step of accumulating difference values for a determined time when the difference value exceeds a predetermined level, and transferring an alarm signal to a driver when the average value thereof exceeds a predetermined level; and a fifth step of starting to accumulate a number of engine starts and driving distance after transferring the alarm signal, and when the number of engine starts is larger than a predetermined value or the driving distance is longer than a predetermined value, if the difference value does not become lower than a predetermined level, recharging a urea tank with a urea solution.