Method and device for operating internal combustion engine having throttle valve and exhaust gas recirculation system for detecting carbon-deposited AGR line

Abstract

The invention relates to a method and a device for carrying out the method, said method specifying the following steps: opening an exhaust gas recirculation valve (108) of an internal combustion engine (100), closing a throttle valve (104) of the internal combustion engine (100), detecting the value of the intake pipe pressure of the internal combustion engine (100) when the exhaust gas recirculation valve (108) is opened and the throttle valve (104) is closed, comparing the value with a first threshold value and a second threshold value (B) larger than the first threshold value, and determining the running state of the internal combustion engine (100) according to whether the value is within a value range between the first threshold value and the second threshold value (B) or outside thevalue range. Therefore, the method can monitor the formation of carbon deposits in different air system components and in particular in the AGR recirculation path, and can achieve a precise positioning with which defective components can also be positioned.

Description

technical field [0001] The invention relates to a method for operating an internal combustion engine with a throttle valve and with an exhaust gas recirculation system (AGR). In particular, the invention relates to a method for monitoring the AGR mass flow, in which method the air system of an internal combustion engine is operated with an open AGR valve and a closed throttle valve. Background technique [0002] For monitoring the AGR mass flow, DE 10 2008 041 804 A1 discloses that the possibility of failure is that carbon deposits, that is to say deposits of soot and oil mist, can occur in the exhaust gas recirculation components, which can be reduced by exhaust gas recirculation The flow cross-section of the line of the assembly may interfere with the way the AGR valve works. However, carbon deposits cannot be detected by monitoring the control deviation, since the carbon deposits are equalized during regulation due to the increased opening of the AGR valve or due to a mo...

AI Technical Summary

Problems solved by technology

However, carbon deposits cannot be detected by monitoring the control deviation, since the carbon deposits are equalized during the regulation due to the increased opening of the AGR valve or due to a more intensive throttling of the fresh air mass flowing through the throttle valve.

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