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

Claim 0:
1. A method for adapting a urea deposit build up model used for estimating an amount of urea deposits in an aftertreatment system of a vehicle comprising a catalytic reduction device, the method comprising the steps of:
determining an amount of ammonia present in the catalytic reduction device;
heating 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;
maintaining the temperature at or above the threshold temperature for time duration until a measured amount of outflow of nitrogen oxides (NOx) is stable thereby indicating that the NOx conversion has stopped;
calculating, for the time duration, an accumulated difference between an inflow amount of NOx and the outflow amount of NOx to obtain total amount of converted NOx during the time duration;
if the determined amount of ammonia exceeds an ammonia threshold, adjusting the total amount of converted NOx according to the determined amount of ammonia and a predetermined relationship between converted NOx and used ammonia;
calculating 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;
adapting 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 storing the adapted urea deposit build up model in a memory storage device.