Patent ID: 11970962
Assignee: VOLVO TRUCK CORPORATION
Field: Environmental technology (Chemistry)
Classification: CPC F  Y | IPC F

Claim 7:
8. An exhaust aftertreatment system of a vehicle comprising:
a catalytic reduction device;
a first NOx sensor upstream of the catalytic reduction device for measuring inflow levels of NOx, and a second NOx sensor downstream of the catalytic reduction device for measuring outflow levels of NOx;
means for heating the catalytic reduction device;
a memory storage device, and
a control unit configured to:
determine an amount of ammonia present in the catalytic reduction device;
control the means to heat the catalytic reduction device to above a threshold temperature to sublime urea deposits in the catalytic reduction device to thereby produce ammonia that adds to the determined amount of ammonia;
control the means to maintaining the temperature at or above the threshold temperature for time duration until a measured amount of outflow amount of NOx is stable thereby indicating that the NOx conversion has stopped;
calculate, for the time duration, an accumulated difference between an inflow amount of NOx measured by the first NOx sensor and the outflow amount of NOx measured by the second NOx sensor to obtain total amount of converted NOx during the time duration;
if the determined amount of ammonia exceeds an ammonia threshold, adjust the total converted NoX according to the determined amount of ammonia and a predetermined relationship between converted NOx and used ammonia;
calculate the amount of urea deposits that were present in the aftertreatment system before the time duration using the calculated total amount of converted NOx, the predetermined relationship between the converted NOx and the used ammonia, and a predetermined relationship between the amount urea deposits and the used ammonia;
adapt a urea deposit build up model so that an output value of the urea deposit build up model corresponds to the calculated amount of urea deposits; and
store the adapted urea deposit build up model in the memory storage device.