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DE-102025118575-B3 - Method for operating a drive unit for a motor vehicle, corresponding drive unit for a motor vehicle and computer program product

DE102025118575B3DE 102025118575 B3DE102025118575 B3DE 102025118575B3DE-102025118575-B3

Abstract

The invention relates to a method for operating a drive unit (1) for a motor vehicle, which has an exhaust gas-generating drive unit (2) and an exhaust gas aftertreatment unit (4) for aftertreating the exhaust gas, wherein a first measured value is taken by means of a first lambda sensor (6) upstream of the exhaust gas aftertreatment unit (4) and a second measured value is taken by means of a second lambda sensor (7) downstream of the exhaust gas aftertreatment unit (4). It is provided that a combustion air ratio is determined from the second measured value, taking into account a correction value determined as a function of the first measured value. The invention further relates to a drive unit (1) for a motor vehicle and a computer program product.

Inventors

  • Bodo Odendall

Assignees

  • AUDI AKTIENGESELLSCHAFT

Dates

Publication Date
20260513
Application Date
20250514

Claims (8)

  1. Method for operating a drive unit (1) for a motor vehicle, which has an exhaust gas-generating drive unit (2) and an exhaust gas aftertreatment device (4) for aftertreating the exhaust gas, wherein a first measured value is measured upstream of the exhaust gas aftertreatment device (4) by means of a first lambda sensor (6) and a second measured value is measured downstream of the exhaust gas aftertreatment device (4) by means of a second lambda sensor (7), wherein a combustion air ratio is determined from the second measured value taking into account a correction value determined as a function of the first measured value, characterized in that an outlet concentration of at least one exhaust gas component downstream of the exhaust gas aftertreatment device (4) is determined by means of an exhaust gas aftertreatment model, to which an inlet concentration determined for an inlet point (16) and an inlet combustion air ratio determined for the inlet point (16) are supplied as input variables, wherein the inlet combustion air ratio is determined at least temporarily using the combustion air ratio determined from the second measured value and the correction value, wherein the The inlet combustion air ratio is determined by interpolation from the first and second measured values.
  2. Procedure according to Claim 1 , characterized in that a switching lambda sensor (6) is used as the first lambda sensor and/or a wideband lambda sensor or a lambda module of a nitrogen oxide sensor (8) is used as the second lambda sensor (7).
  3. Method according to one of the preceding claims, characterized in that the correction value is determined by comparing the second measured value with a reference value determined from the first measured value.
  4. Procedure according to Claim 3 , characterized in that the reference value is determined using at least one signal filter having a linear time-invariant transfer element.
  5. Procedure according to Claim 3 or 4 , characterized in that the correction value is determined by forming a mean value of a difference between the second measured value and the reference value or by calculating a difference between a mean value of the second measured value and a mean value of the reference value.
  6. Method according to one of the preceding claims, characterized in that the correction value is determined if at least one of the following conditions is met: the first lambda probe (6) is operational, the second lambda probe (7) is operational, the heat input into the exhaust aftertreatment device (4) is less than a heat input threshold value, an operating point of the drive unit (2) lies within an operating point range, a temporal change of the operating point lies within a change range, and a temperature of the exhaust aftertreatment device (4) lies within a temperature range.
  7. Drive unit (1) for a motor vehicle, in particular for carrying out the method according to one or more of the preceding claims, wherein the drive unit (1) has an exhaust gas generating drive unit (2) and an exhaust gas aftertreatment unit (4) for aftertreating the exhaust gas and is provided and configured to measure a first measured value by means of a first lambda sensor (6) upstream of the exhaust gas aftertreatment unit (4) and a second measured value by means of a second lambda sensor (7) downstream of the exhaust gas aftertreatment unit (4), wherein the drive unit (1) is also provided and configured to determine an air-fuel ratio from the second measured value, taking into account a correction value determined as a function of the first measured value, characterized in that an outlet concentration of at least one exhaust gas component downstream of the exhaust gas aftertreatment unit (4) is determined by means of an exhaust gas aftertreatment model, to which an inlet concentration determined for an inlet point (16) and an inlet air-fuel ratio determined for the inlet point (16) are supplied as input variables, wherein the The inlet combustion air ratio is determined at least temporarily using the combustion air ratio determined from the second measured value and the correction value, wherein the inlet combustion air ratio is determined by interpolation from the first measured value and the second measured value.
  8. Computer program product, comprising commands that cause the drive device (1) to Claim 7 the procedure according to one or more of the Claims 1 until 6 executes.

Description

The invention relates to a method for operating a drive unit for a motor vehicle, which has an exhaust gas-generating drive unit and an exhaust aftertreatment device for treating the exhaust gas, wherein a first measured value is taken by means of a first lambda sensor upstream of the exhaust aftertreatment device and a second measured value is taken by means of a second lambda sensor downstream of the exhaust aftertreatment device, wherein a combustion air ratio is determined from the second measured value, taking into account a correction value determined as a function of the first measured value. The invention further relates to a drive unit for a motor vehicle and a computer program product. For example, printed matter is state of the art. DE 10 2018 216 980 A1 This is known. This describes a method for controlling the filling of an exhaust gas component storage tank of a catalyst in the exhaust gas of an internal combustion engine, in which a first catalyst model is supplied with signals from a first exhaust gas sensor extending upstream of the catalyst into the exhaust gas stream and detecting a concentration of the exhaust gas component, in addition to other signals, and an actual fill level of the exhaust gas component storage tank is determined, whereby a lambda setpoint is generated, a predetermined target fill level is converted into a base lambda setpoint, a deviation of the actual fill level from the predetermined target fill level is determined and processed by a fill level control into a lambda setpoint correction value, a sum of the base lambda setpoint and the lambda setpoint correction is calculated and the sum is used to generate a correction value with which a fuel metering to at least one combustion chamber of the internal combustion engine is influenced. Furthermore, the printed text states DE 10 2015 117 530 B 4. A system for the aftertreatment of an exhaust gas flow, comprising: a first NOₓ sensor configured to monitor a first NOₓ concentration value; and a computer-based processor device; wherein the first NOₓ sensor is configured to also monitor a first lambda value in the exhaust gas flow. The first NOₓ sensor is located upstream of a lean NOₓ trap device; the system comprises a second NOₓ sensor downstream of the lean NOₓ trap device and upstream of an SCRF device, the second NOₓ sensor being configured to monitor a second lambda value and a second NOₓ concentration value in the exhaust gas flow downstream of the lean NOₓ trap device; the computer-based processor device being configured to calibrate the monitored first lambda value with respect to the presence of H₂ . and wherein the computer-based processor device is further configured to calibrate the monitored first NO x concentration value, comprising approximating NO x by readings of the first NO x sensor if the calibrated lambda value indicates lean operation, and approximating NH 3 by the dimensions of the first NO x sensor if the calibrated lambda value indicates rich operation. Furthermore, the printed text DE 41 12 477 C2 A method for simulating the temporal behavior of the lambda value at the outlet of an exhaust gas catalyst in a motor vehicle with an internal combustion engine is known. The printed matter DE 10 2013 216 595 A1 This relates to a method for correcting the voltage-lambda characteristic curve of a second lambda sensor located in the exhaust stream of an internal combustion engine downstream of a catalytic converter, wherein an output signal from a first lambda sensor located upstream of the catalytic converter is acquired and corrected. The method involves operating the internal combustion engine at a point where the lambda values of the exhaust gas before and after the catalytic converter are equal, setting the temperature of the second lambda sensor to a target temperature, comparing the first lambda value determined by the first lambda sensor with the second lambda value determined by the second lambda sensor, determining the temperature of the second lambda sensor to be corrected from the comparison of the first and second lambda values, and correcting the voltage-lambda characteristic curve of the second lambda sensor by taking into account the temperature deviation between the target temperature and the temperature to be corrected. Printed materials are still state-of-the-art. DE 42 12 022 A1 and DE 10 2023 201 660 B3 known. The object of the invention is to propose a method for operating a drive unit for a motor vehicle which has advantages over known methods, in particular enabling the provision of a combustion air ratio based on the second measured value with high accuracy. According to the invention, this is achieved by a method for operating a drive unit for a motor vehicle with the features of claim 1. It is provided that an outlet The concentration of at least one exhaust gas component downstream of the exhaust aftertreatment device is determined using an exhaust aftertreatment model, to whi