Patent ID: 8561387
Filing Date: 2013-10-22
Classification: F01N,Y02T

Abstract:
1. A method for checking the seal of a reducing agent injector of an SCR exhaust gas aftertreatment system of an internal combustion engine comprising a least one reducing agent tank, a reducing agent pump, a reducing agent injector and an NOx sensor connected downstream from the SCR catalytic converter, the method comprising the steps of: a) generating and/or detecting a release state of the SCR system in which no reducing agent is stored in the SCR catalytic converter, b) determining a setpoint NOx value in the exhaust gas using either a computer model or an additional NOx sensor, c) maintaining the reducing agent injector in a closed position while increasing the reducing agent pressure to a pressure higher than a pressure range of the reducing agent pressure during a normal operation of the SCR exhaust gas aftertreatment system, d) detecting an NOx signal at the NOx sensor, e) evaluating the NOx signal by: