Patent Number: 8,024,921

Title: Method for operating an internal combustion engine and device for carrying out the method

Abstract: A method for operating an internal combustion engine in whose exhaust gas region at least one SCR catalytic converter is arranged, a reagent which contributes to NOx conversion in the SCR catalytic converter being applied to said SCR catalytic converter, and a device for carrying out the method are proposed. A measure for the NOx current which occurs downstream of the SCR catalytic converter is both calculated and measured with an NOx sensor which has lateral sensitivity to the reagent. The difference between the calculated measure and the measured measure of the NOx current is determined. A reagent signal which defines the metering of the reagent is influenced as a function of the difference. Plausibility checking is provided, during which the reagent quantity which is metered in a predefined time period and the reagent quantity which is converted in the SCR catalytic converter and/or the converted NOx quantity are compared with one another. When a deviation is detected, a correction signal which also influences the reagent signal is made available.

Inventors: Walz; Christian (Durmersheim, DE), Loehr; Matthias (Steinheim/Hoepfigheim, DE), Rudolph; Andreas (Roggenburg, DE)

Assignee: Robert Bosch GmbH

International Classification: F01N 3/00 (20060101); F01N 3/10 (20060101)

Expiration Date: 2019-09-27 0:00:00