Method and device for diagnosing and for calibrating an exhaust gas sensor

Patent metadata

Field	Value
Publication number	US-10539088-B2
Application number	US-201715711520-A
Country	US
Kind code	B2
Filing date	Sep 21, 2017
Priority date	Oct 6, 2016
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A method for diagnosing and calibrating an exhaust gas sensor. An exhaust gas mass flow generated by an internal combustion engine is divided and a first part of the exhaust gas flow is conducted through a first exhaust gas path of a motor vehicle, and a second part of the exhaust path mass flow is conducted through a second exhaust gas path of the motor vehicle.

First claim

The invention claimed is:

1. A method for diagnosing and calibrating an exhaust gas sensor, comprising:
a mass flow of exhaust gas generated by an internal combustion engine is conducted through a first exhaust gas path of a motor vehicle, and a second part of the exhaust gas flow is conducted through a second exhaust gas path of the motor vehicle, wherein the first exhaust gas path and the second exhaust gas path have at least one exhaust gas post treatment element and at least one exhaust gas sensor arranged in a flow direction of the exhaust gas mass flow after the at least one exhaust gas post treatment element, wherein an exhaust gas post treatment output of the at least one exhaust gas post treatment element of the first exhaust gas path is smaller than an output of the exhaust gas post treatment of the at least one exhaust gas post treatment element of the second exhaust gas path and wherein pollutants detected by at least one exhaust gas sensor comprised in the first exhaust gas path are compared to pollutant values detected by the at least one exhaust gas sensor of the second exhaust gas path, and at least one proportionality factor is determined between the pollutant values determined by the at least one exhaust gas sensor of the first exhaust gas path, and the pollutant values detected by the at least one exhaust gas sensor of the second exhaust gas path, and based on a matching of a specified diagnostic value to at least one proportionality factor, a diagnosis of an exhaust gas system is issued, having the first exhaust gas path and the second exhaust gas path, or wherein the at least one exhaust gas sensor of the second exhaust gas path is calibrated,
wherein the exhaust gas mass flow is divided and a volumetric flow conducted through the first exhaust gas path is smaller than the volumetric flow conducted through the second exhaust gas path.

2. The method according to claim 1 , wherein the exhaust gas system is diagnosed as being faulty when the at least one proportionality factor deviates by an amount of at least a specified exceeding value which is greater than a specified threshold value.

3. The method according to claim 1 , wherein the internal combustion engine is switched into an operating mode in which the exhaust gas system is impacted with an exhaust gas that has a concentration of pollutants wherein at least one exhaust gas sensor of the first exhaust gas path is exposed to a concentration of pollutants that is higher than a specified limiting value, wherein the concentration of pollutants of a total exhaust gas mass flow emitted by the exhaust gas system remains below the predetermined limiting value, and wherein the at least one exhaust gas sensor of the second exhaust gas path is tested based on a mass value determined with the exhaust gas impact of the first exhaust gas path of the at least one exhaust gas sensor, wherein the at least one exhaust gas sensor of the second exhaust gas path is tested by respective measured values determined by the at least one exhaust gas sensor of the first exhaust path while being impacted by the exhaust gas, and wherein the measured values are corrected by the at least one proportionality factor and the correspondingly corrected measured values are compared to a respective highest value.

4. The method according to claim 1 , wherein the internal combustion engine is switched to an operating mode so that the exhaust gas system is impacted with exhaust gas that has a concentration of pollutants resulting in that the at least one exhaust gas sensor of the first exhaust gas path is exposed to a concentration of pollutants that is higher than a specified limiting value, wherein the concentration of pollutants of the exhaust gas system emitted with the total exhaust gas mass flow remains under the specified limiting value, and wherein the at least one exhaust gas sensor of the second exhaust gas path is calibrated based on a measured value determined with the exhaust gas during an impacting with the exhaust gas of the first exhaust gas path by the at least one exhaust gas sensor, wherein the measured value of the at least one exhaust gas sensor of the second exhaust gas path determined during the impacting of the at least one exhaust gas sensor of the first exhaust gas path is corrected and standardized with the proportionality factor.

5. An exhaust gas system for an internal combustion engine, comprising:
a control device, a first exhaust gas path and a second exhaust gas path, wherein the first exhaust gas path has at least one exhaust gas post treatment element, the exhaust gas post treatment output of which is reduced relative to an exhaust gas post treatment output of an exhaust gas post treatment element, wherein the first exhaust gas path and the second exhaust gas path are provided with at least one exhaust gas sensor arranged in an exhaust gas flow direction after an exhaust gas post treatment element for the exhaust gas that is generated by the internal combustion engine, wherein the control device is configured to determine pollutant values of a first part of the exhaust gas flow of the exhaust gas mass flow generated by the internal combustion engine measured by at least one exhaust gas sensor of the first exhaust gas path, and to compare them to values of the pollutants of a second part of an exhaust gas mass flow generated by the internal combustion engine determined by an exhaust gas sensor of the second exhaust gas path, and to issue at least one proportionality factor for proportionality between the values of the pollutants determined by the at least one exhaust gas sensor of the first exhaust gas path and the at least one exhaust gas sensor of the second exhaust gas path, and to issue, based on a matching of the values to a predetermined diagnostic value, a diagnosis of the exhaust gas system with the at least one proportionality factor,
wherein the first exhaust gas path and the second exhaust gas path are configured for the exhaust gas mass flow to be divided and a volumetric flow conducted through the first exhaust gas path is smaller than the volumetric flow conducted through the second exhaust gas path.

6. The exhaust gas system according to claim 5 , wherein the first exhaust gas path and the second exhaust gas path are deployed within an exhaust gas post treatment module of the exhaust gas system.

7. The exhaust gas system according to claim 5 , wherein the first exhaust gas path and the second exhaust gas path are arranged to being spatially separated from each other.

8. A system, for diagnosing and calibrating an exhaust gas sensor comprising:
one or more non-transitory computer readable medium; and
at least one processor communicatively coupled to the one or more non-transitory computer readable medium, the processor operable:
to read out measured values determined by respective exhaust gas sensors of an exhaust gas system, and to compare the measured values determined by at least one exhaust sensor of a first exhaust gas path to the measured values determined by at least one exhaust gas sensor of a second exhaust gas path, and to calculate at least one proportionality factor based on the comparison, and to issue an error message when the at least one proportionality factor deviates by an amount of a specified limiting value which is greater than a predetermined threshold value,
wherein an exhaust gas mass flow is divided and a volumetric flow conducted through the first exhaust gas path is smaller than the volumetric flow conducted through the second exhaust gas path.

Assignees

• Audi Ag

Inventors

• Rausing Johannes
• Neukam Johannes

Classifications

• F02D41/1439

  characterised by the position of the sensor · CPC title

• F02D41/2474

  Characteristics of sensors · CPC title

• F01N13/017

  the purifying devices are arranged in a single housing · CPC title

• F01N2560/02

  the means being an exhaust gas sensor · CPC title

• F02D41/1495

  Detection of abnormalities in the air/fuel ratio feedback system · CPC title