Method and control unit for regulating a fill level of a storage of a catalytic converter for an exhaust gas component

Patent metadata

Field	Value
Publication number	US-11111873-B2
Application number	US-201916429120-A
Country	US
Kind code	B2
Filing date	Jun 3, 2019
Priority date	Jun 1, 2018
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A filling of an exhaust gas component storage of a catalytic converter is regulated. An actual fill level of the exhaust gas component storage is ascertained using a first system model, and a base lambda setpoint value for a first control loop is predefined by a second control loop. An initial value for the base lambda setpoint value is converted into a fictitious fill level, the fictitious fill level being compared with a setpoint value for the fill level output, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if a difference between the setpoint value for the fill level and the fictitious fill level is greater than a predefined degree. The base lambda setpoint value is not changed if no difference exists between the setpoint value for the fill level and the fictitious fill level.

First claim

What is claimed is:

1. A method for regulating a filling of an exhaust gas component storage of a catalytic converter in an exhaust gas of an internal combustion engine, comprising:
ascertaining an actual fill level of the exhaust gas component storage using a first system model;
feeding to the first system model a signal of a first exhaust gas sensor projecting into an exhaust gas flow upstream from the catalytic converter and detecting a concentration of the exhaust gas component;
predefining in the first system model a base lambda setpoint value for a first control loop, the predefining being performed by a second control loop;
converting, in the second control loop, an initial value for the base lambda setpoint value into a fictitious fill level by a second system model identical to the first system model;
comparing the fictitious fill level with a setpoint value for a fill level, the comparing producing a comparison result; and
iteratively changing the base lambda setpoint value as a function of the comparison result, if the comparison result indicates a difference between the setpoint value for the fill level and the fictitious fill level that is greater than a predefined degree, wherein the base lambda setpoint value is not changed if the comparison result indicates no difference between the setpoint value for the fill level and the fictitious fill level.

2. The method as recited in claim 1 , further comprising:
ascertaining and processing by a fill level regulation a deviation of the actual fill level from the setpoint value for the fill level in order to form a lambda setpoint value correction value;
forming a sum from the base lambda setpoint value and the lambda setpoint value correction value;
forming a correction value on the basis of the sum; and
influencing a fuel metering to at least one combustion chamber of the internal combustion engine by the correction value.

3. The method as recited in claim 1 , wherein:
the exhaust gas component is oxygen,
a lambda regulation takes place in the first control loop,
the lambda regulation includes processing the signal of the first exhaust gas sensor as a lambda actual value,
a lambda setpoint value is formed in the second control loop,
a fill level control deviation is formed as a deviation of the fill level modeled using the first catalytic converter model from the filtered fill level setpoint value,
the fill level control deviation is fed to a fill level control algorithm that therefrom forms a lambda setpoint value correction value,
the lambda setpoint value correction value is used to form a sum by being added to the iteratively changed base lambda setpoint value, and
the sum forms the lambda setpoint value.

4. The method as recited in claim 1 , wherein the first system model contains a catalytic converter model.

5. The method as recited in claim 4 , wherein the catalytic converter model includes an input emissions model and a fill level and emissions level model.

6. The method as recited in claim 5 , wherein the catalytic converter model includes sub-models, each of which is assigned a sub-volume of the catalytic converter.

7. The method as recited in claim 5 , wherein:
the catalytic converter model includes an output lambda model that is configured to convert with the aid of the first catalytic converter model calculated concentrations of individual exhaust components into a signal that corresponds to a signal of a second exhaust gas sensor situated downstream from the catalytic converter and exposed to the exhaust gas.

8. The method as recited in claim 7 , wherein the signal calculated using the output lambda model is balanced with the signal measured by the second exhaust gas sensor.

9. The method as recited in claim 7 , wherein:
the catalytic converter is a three-way catalytic converter, and
parameters of the first system model are successively changed until a lambda value modeled for the exhaust gas flowing out of the three-way catalytic converter corresponds to a lambda value measured at the three-way catalytic converter.

10. The method as recited in claim 1 , wherein the predefined base lambda setpoint value amounts to between 10% and 50% of a maximum oxygen storage capacity of the catalytic converter.

11. The method as recited in claim 1 , wherein the predefined base lambda setpoint value amounts to between 25% and 35% of a maximum oxygen storage capacity of the catalytic converter.

12. A control unit for regulating a filling of an exhaust gas component storage of a catalytic converter in an exhaust gas of an internal combustion engine, comprising:
an arrangement for ascertaining an actual fill level of the exhaust gas component storage using a first system model;
an arrangement for feeding to the first system model a signal of a first exhaust gas sensor projecting into an exhaust gas flow upstream from the catalytic converter and detecting a concentration of the exhaust gas component;
an arrangement for predefining in the first system model a base lambda setpoint value for a first control loop, the predefining being performed by a second control loop;
an arrangement for converting, in the second control loop, an initial value for the base lambda setpoint value into a fictitious fill level by a second system model identical to the first system model;
an arrangement for comparing the fictitious fill level with a setpoint value for a fill level, the comparing producing a comparison result; and
an arrangement for iteratively changing the base lambda setpoint value as a function of the comparison result, if the comparison result indicates a difference between the setpoint value for the fill level and the fictitious fill level that is greater than a predefined degree, wherein the base lambda setpoint value is not changed if the comparison result indicates no difference between the setpoint value for the fill level and the fictitious fill level.

13. The control unit as recited in claim 12 , further comprising:
an arrangement for ascertaining and processing by a fill level regulation a deviation of the actual fill level from the setpoint value for the fill level in order to form a lambda setpoint value correction value;
an arrangement for forming a sum from the base lambda setpoint value and the lambda setpoint value correction value;
an arrangement for forming a correction value on the basis of the sum; and
an arrangement for influencing a fuel metering to at least one combustion chamber of the internal combustion engine by the correction value.

Assignees

• Bosch Gmbh Robert

Inventors

• Wagner Alexandre
• Fey Michael

Classifications

• F02D41/1445

  the characteristics being related to the exhaust flow · CPC title

• F02D35/0046

  Controlling fuel supply · CPC title

• F01N9/00

  Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00) · CPC title

• F02D2041/1434

  Inverse model · CPC title

• F01N2560/025

  for measuring or detecting O2, e.g. lambda sensors · CPC title