Determination of an ash loading of a particulate filter for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11268425-B2
Application number	US-201917053673-A
Country	US
Kind code	B2
Filing date	May 3, 2019
Priority date	May 9, 2018
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A measuring device for the determination of an ash loading of a particulate filter for an internal combustion engine of a motor vehicle, where a regeneration operation of the particulate filter is carried out such that, after termination of the regeneration operation, a predefined, minimum soot loading remains on the particulate filter. The measuring device is configured to determine an actual regeneration variable which is characteristic for a loading combustion operation during the regeneration operation of the particulate filter via a pressure sensor which is attached downstream in the exhaust gas flow of the particulate filter in the exhaust gas system of the internal combustion engine. The measuring device is further configured to determine the ash loading of the particulate filter dependent on the actual regeneration variable and a variable which is characteristic for the time duration of the regeneration operation.

First claim

What is claimed is:

1. An apparatus for determining an ash loading of a particulate filter for an internal combustion engine of a motor vehicle, comprising:
a measuring device, wherein the measuring device is configured to:
ascertain, via a pressure sensor fitted in an exhaust system of the internal combustion engine downstream of the particulate filter in an exhaust-gas flow, an actual regeneration variable which is characteristic of a loading burn-off operation during a regeneration process of the particulate filter, wherein after completion of the regeneration process, a predefined minimal soot loading of at least 25% remains in the particulate filter and wherein a loading of the particulate filter with both ash and soot contributes to a pressure measured by the pressure sensor; and
determine the ash loading of the particulate filter dependent on the actual regeneration variable and on a variable which is characteristic of a time duration of the regeneration process.

2. The apparatus according to claim 1 , wherein the measuring device is configured to:
ascertain, via a burn-off model and dependent on the time duration of the regeneration process, a modeled regeneration variable which is characteristic of the loading burn-off operation during the regeneration process, and
determine the ash loading of the particulate filter dependent on a deviation between the actual regeneration variable and the modeled regeneration variable.

3. The apparatus according to claim 2 , wherein the burn-off model is configured to ascertain the modeled regeneration variable, which is characteristic of the loading burn-off operation during the regeneration process, dependent on an exhaust-gas volume flow and/or on an exhaust-gas temperature and/or on a loading of the particulate filter.

4. The apparatus according to claim 2 , wherein the measuring device is configured to:
determine, via the pressure sensor, a first loading variable which is characteristic of a loading of the particulate filter before the regeneration process;
ascertain, via the burn-off model and dependent on the time duration of the regeneration process, a second loading variable which is characteristic of a loading of the particulate filter after the regeneration process; and
ascertain the modeled regeneration variable dependent on a deviation between the first loading variable and the second loading variable.

5. The apparatus according to claim 2 , wherein the measuring device is configured to:
ascertain, at a first point in time and at a second point in time, a respective actual regeneration variable and a respective modeled regeneration variable; and
detect an increase in the ash loading of the particulate filter at the second point in time, which follows the first point in time, if a respective deviation between the respective actual regeneration variable and the respective modeled regeneration variable is greater at the second point in time than at the first point in time.

6. The apparatus according to claim 2 , wherein the measuring device is configured to:
ascertain, at three points in time, a respective actual regeneration variable and a respective modeled regeneration variable; and
detect an increase in the ash loading of the particulate filter if a deviation, aggregated over at least two of the three points in time, between the respective actual regeneration variable and the respective modeled regeneration variable is greater at a later point in time than at a point in time which is earlier than the later point in time.

7. The apparatus according to claim 1 , wherein the measuring device is configured to:
determine, via the pressure sensor, a first loading variable which is characteristic of a loading of the particulate filter before the regeneration process;
determine, via the pressure sensor, a second loading variable which is characteristic of a loading of the particulate filter after the regeneration process; and
ascertain the actual regeneration variable dependent on a deviation between the first loading variable and the second loading variable.

8. The apparatus according to claim 1 , wherein the measuring device is configured to:
determine, via the pressure sensor, a loading variable which is characteristic of a loading of the particulate filter;
start the regeneration process by an engine control unit if a first threshold value for the loading variable is attained or overshot;
end the regeneration process by the engine control unit if a second threshold value for the loading variable is attained or undershot; and
determine the ash loading of the particulate filter dependent on the time duration of the regeneration process.

9. The apparatus according to claim 8 , wherein the regeneration process is comprised of at least one regeneration phase and wherein the measuring device is configured to:
determine the loading variable via the pressure sensor after completion of the at least one regeneration phase; and
start a second regeneration phase if the loading variable does not attain or undershoots the second threshold value.

10. A measuring method for determining an ash loading of a particulate filter for an internal combustion engine of a motor vehicle, comprising the steps of:
performing a regeneration process of the particulate filter such that, after completion of the regeneration process, a predefined minimal soot loading of at least 25% remains in the particulate filter;
ascertaining by a measuring device via a pressure sensor fitted in an exhaust system of the internal combustion engine downstream of the particulate filter an actual regeneration variable which is characteristic of a loading burn-off operation during the regeneration process of the particulate filter, wherein a loading of the particulate filter with both ash and soot contributes to a pressure measured by the pressure sensor; and
determining by the measuring device the ash loading of the particulate filter dependent on the actual regeneration variable and on a variable which is characteristic of a time duration of the regeneration process.

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Schulz Ralf

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02D41/1448

  the characteristics being an exhaust gas pressure · CPC title

• F01N9/002 Primary

  of filter regeneration · CPC title

• F01N2900/0422

  measuring the elapsed time · CPC title

• F01N2900/1611

  Particle filter ash amount · CPC title