Patent ID: 7905085
Filing Date: 2011-03-15
Classification: B01D,F01N,F23J,Y02T

Abstract:
1. A method for operating an internal combustion engine, in whose exhaust gas system an exhaust gas treatment device is situated, the method comprising: introducing a reagent into the exhaust gas system upstream from the exhaust gas treatment device; using a reagent pump for bringing the reagent to a predefined reagent setpoint pressure that is set to a nominal reagent pressure during a dosing of the reagent; performing the dosing of the reagent using a reagent dosing valve; detecting a reagent pressure upstream from the reagent dosing valve, the reagent setpoint pressure having a predefined time curve during a diagnosis, wherein the curve is superimposed on the nominal reagent pressure; comparing the reagent pressure, which is detected in at least one predefined state of the reagent dosing valve, to at least one threshold value associated with the nominal reagent pressure after taking into account the curve of the reagent setpoint pressure; and providing an error signal if the reagent pressure exceeds the threshold value.