Patent ID: 9140170
Filing Date: 2015-09-22
Classification: F01N,Y02A,Y02T

Abstract:
1. A method of improving the performance of a selective catalytic reduction (SCR) device of a vehicle having an engine and an exhaust gas system, the method comprising: selecting, via a controller, an initial injection rate and an initial injection temperature for a reductant, the initial injection temperature defined as the temperature of the exhaust gas system when the reductant is injected; initiating, via the controller, an injection of the reductant into the exhaust gas system via an injection device, including injecting the reductant at the initial injection temperature and the initial injection rate; estimating, via a reductant deposit module, an instantaneous amount of accumulated reductant deposits present within the exhaust gas system based on each of the initial injection rate, the initial injection temperature, and an exhaust flow rate through the exhaust gas system; comparing, with the controller, the amount of accumulated reductant deposits to a threshold amount of deposits allowable in the exhaust gas system; executing, via the controller, a first control action when the amount of accumulated reductant deposits is less than the threshold amount of deposits allowable in the exhaust gas system and a second control action when the amount of accumulated reductant deposits is greater than the threshold amount of deposits allowable in the exhaust gas system; wherein the first control action includes repeatedly comparing, via the controller, the amount of accumulated reductant deposits to the threshold amount of deposits allowable in the exhaust gas system until the amount of accumulated reductant deposits is equal to the threshold amount of deposits allowable in the exhaust gas system and initiating the second control action when the amount of accumulated reductant deposits is equal to the threshold amount of deposits allowable in the exhaust gas system; and wherein the second control action includes evaluating, via the controller, an amount of soot accumulated in a particulate filter of the exhaust gas system and initiating a reductant deposit burn-off mode within the exhaust gas system, wherein the reductant deposit burn-off mode is defined as an exposure of the accumulated reductant deposits to an exhaust gas system cleaning temperature, such that the exhaust gas cleaning temperature is a temperature of the exhaust gas system sufficient to burn off the accumulated reductant deposits.