Robert Boschgmbh

Alexander Franz

Tobias Pfister

Cornelia Nagel

Arthur Bastoreala

Andreas Fritsch

In a method for heating an exhaust system of a combustion engine of a motor vehicle, the exhaust system comprises at least two components for exhaust gas cleaning. For at least one component, a temperature regulation is provided for heating the component while using a heating operation mode. For the heating of the exhaust system, a heating operation is used via a pulse control with heating pulses () and heating pauses (), which switches between a heating operation mode and a normal operation without heating measures.

Method for heating an exhaust system of a combustion engine of a motor vehicle

The invention concerns a method for monitoring an SCR catalytic converter in an exhaust line of an internal combustion engine, into which a reducing agent solution for the reduction of nitrogen oxides is dosed, wherein the SCR catalytic converter is diagnosed as defective if a measured variable is below a corresponding threshold and wherein the diagnosis of the SCR catalytic converter occurs when enabling criteria are met, wherein the enabling criteria are selected depending on a BPU model and a WPA model such that when the SCR catalytic converter () conforms to the BPU model, ammonia slip occurs through this SCR catalytic converter (), and when the SCR catalytic converter corresponds to the WPA model, no ammonia slip occurs through this SCR catalytic converter.

Method of monitoring an SCR catalytic converter

In a method for diagnosing an SCR catalyst system of an internal combustion engine, the SCR catalyst system comprises at least one first SCR catalyst device () and at least one second SCR catalyst device (). A first injection position upstream of the first SCR catalyst device () in the form of a first metering device () is provided for injecting liquid reducing agent for the SCR catalyst devices (). A second injection position between the two SCR catalyst devices () in the form of a second metering device () is furthermore provided. Both SCR catalyst devices () are monitored in a differentiated way by means of active and passive diagnostic methods.

Method for the diagnosis of an SCR catalyst system of an internal combustion engine

In the case of a method for operating an exhaust gas aftertreatment system of a motor vehicle, the exhaust gas aftertreatment system comprises at least one NOx storage catalyst () and at least one SCR catalyst (). According to the invention, when an inadequate function of the NOx storage catalyst () or of the SCR catalyst () is identified, at least one auxiliary measure is initiated which leads to a reduction of the NOx emissions of the motor vehicle.

Method for operating an exhaust gas aftertreatment system of a motor vehicle

In a method for operating an SCR catalytic converter system of an internal combustion engine, the SCR catalytic converter system comprises at least one SCR catalytic converter () and at least one upstream SCR-coated particulate filter (). In order to inject liquid reducing agent for the SCR catalytic converter () and/or for the SCR-coated particulate filter (), a first injection position is provided upstream of the SCR-coated particulate filter () in the form of a first metering device () and a second injection position is provided upstream of the SCR catalytic converter () and downstream of the SCR-coated particulate filter () in the form of a second metering device (). The injection positions for the injection of liquid reducing agent are selected in a manner which is dependent on the operating states of the SCR catalytic converter system.

Method for operating an SCR catalytic converter system of an internal combustion engine

In a method for the diagnosis of an exhaust gas aftertreatment system for an internal combustion engine, the exhaust gas aftertreatment system comprises at least one NOx storage catalytic converter () and at least one SCR catalytic converter () which is arranged downstream of the NOx storage catalytic converter (). According to the invention, a regeneration of the NOx storage catalytic converter () is blocked and/or interrupted in order to improve the frequency and/or quality of the diagnosis of the SCR catalytic converter ().

Method for the diagnosis of an exhaust gas aftertreatment system for an internal combustion engine

In the case of a method for checking the plausibility of a NOx sensor () in an SCR catalytic converter system having at least one first SCR catalytic converter device () and having at least one second SCR catalytic converter device () and having in each case one dosing point () for a reducing agent solution for the SCR catalytic converter devices () upstream of the respective SCR catalytic converter device, the NOx sensor () to be checked for plausibility is situated either between the first SCR catalytic converter device () and the second SCR catalytic converter device (), or the NOx sensor () to be checked for plausibility is situated downstream of the second SCR catalytic converter device ().

Method for checking the plausibility of a NOx sensor in an SCR catalytic converter system

In a method for monitoring an SCR catalyst, in particular for monitoring the storage capacity of the SCR catalyst for ammonia, superstoichiometric metering () of reducing agents into the SCR catalyst is performed for diagnostic purposes, and the storage capacity of the SCR catalyst is inferred in accordance with at least one characteristic value, which is dependent on the nitrogen oxide conversion rate of the SCR catalyst. In this method, a conditioning phase () for setting a specifiable operating point () is carried out before the superstoichiometric metering () of reducing agents.

Method for monitoring an SCR catalyst

A method is provided for monitoring an SCR catalytic converter (), in which method the NHstorage capacity of the SCR catalytic converter () is monitored. The SCR catalytic converter () is initially filled in an overdosing phase with a superstoichiometric reducing agent dosing up to the maximum NHstorage capacity. The catalytic converter is subsequently acted on in an underdosing phase with a reducing agent dosing which is reduced in relation to a normal dosing or is absent. The NHstorage capacity is indirectly determined during the underdosing phase by determining at least one characteristic value which is dependent on the NOconversion rate. According to the invention, to detect NHslippage (), which indicates the transition from the overdosing phase to the underdosing phase, a variable which is characteristic of the NOx conversion is continuously measured during the overdosing phase, and in the event of a fall in the NOx conversion, it is inferred that NHslippage () is present.

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Gaertringen, Germany

Alexander Franz