Method for self-balancing of a lambda sensor and exhaust gas system

Patent metadata

Field	Value
Publication number	US-12345600-B2
Application number	US-202318202448-A
Country	US
Kind code	B2
Filing date	May 26, 2023
Priority date	Jun 13, 2022
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

A method for self-balancing of a lambda sensor ( 18, 20, 26 ) is provided. The method measures pumping current (Ip) and pumping voltage (Up) of the lambda sensor ( 18, 20, 26 ), and checks whether the measured pumping current (Ip) and the measured pumping voltage (Up) lie within a specified tolerance range ( 33 ). If values lie outside the tolerance range ( 33 ) of the characteristic curve specification, an adjustment of the lambda value (λ) occurs with the aid of the pumping voltage (Up) of the lambda sensor ( 18, 20, 26 ), and, in a substantially adjusted state, a further pumping current (Ip) of the lambda sensor ( 18, 20, 26 ) is measured and the pumping current offset ( 32 ) is derived from the further pumping current (Up). Thus, precise self-balancing of the lambda sensor ( 18, 20, 26 ) is carried out, thereby enabling a good exhaust gas after-treatment.

First claim

The invention claimed is:

1. A method for self-alignment of a lambda sensor ( 18 , 20 , 26 ) for an exhaust gas system ( 10 ) of a motor vehicle propelled by an internal combustion engine, comprising:
measuring a pumping current (I p ) of the lambda sensor ( 18 , 20 , 26 ) provided for detecting a lambda value (Δ);
measuring a pumping voltage (U p ) of the lambda sensor ( 18 , 20 , 26 ) correlating to the pumping current (I p );
checking whether the measured pumping current (I p ) and the measured pumping voltage (U p ) lie within a specified tolerance range ( 33 ) of a characteristic curve specification for a dependence between the pumping current (I p ) and the pumping voltage (U p ); and
when the values lie outside the tolerance range ( 33 ) of the characteristic curve specification, then adjusting the lambda value (λ) based on the pumping voltage (U p ) of the lambda sensor ( 18 , 20 , 26 ) rather than based on the pumping current (I p ) of the lambda sensor ( 18 , 20 , 26 ), and, in an adjusted state, measuring a further pumping current (I p ) of the lambda sensor ( 18 , 20 , 26 ) and, for self-alignment of the lambda sensor ( 18 , 20 , 26 ), deriving a pumping current offset ( 32 ) from at least one of:
a further pumping current (U p ) for a compensation of a leakage current,
a fault current of the lambda sensor ( 18 , 20 , 26 ), and
a cable harness belonging to the lambda sensor ( 18 , 20 , 26 ).

2. The method of claim 1 , wherein, after the self-alignment of the lambda sensor ( 18 , 20 , 26 ), instead of using the pumping voltage (U p ) of the lambda sensor ( 18 , 20 , 26 ) to detect a lambda value (λ), the method includes using the pumping current (I p ) of the lambda sensor ( 18 , 20 , 26 ) corrected by the pumping current offset ( 32 ) to detect a lambda value (λ).

3. The method of claim 1 , wherein the lambda sensor ( 18 , 20 , 26 ) is configured as a broadband lambda sensor.

4. An exhaust gas system ( 10 ) for a motor vehicle propelled by an internal combustion engine, comprising:
a first lambda sensor ( 18 ) for detecting a first lambda value of a first motor bank ( 14 ) of an internal combustion engine ( 12 ),
a second lambda sensor ( 20 ) for detecting a second lambda value of a second motor bank ( 16 ) of the internal combustion engine ( 12 ),
a motor bank control system for adjusting the first motor bank ( 14 ) and the second motor bank ( 16 ) such that substantially equal lambda values are achieved for the first motor bank ( 14 ) and for the second motor bank ( 16 ),
wherein the first and second lambda sensors ( 18 , 20 ) comprise first and second self-balancing adjusters configured to:
measure a pumping current (I p ) of the lambda sensors for detecting a lambda value (λ);
measure a pumping voltage (U p ) of the lambda sensors correlating to the pumping current (I p );
check whether the measured pumping current (I p ) and the measured pumping voltage (U p ) lie within a specified tolerance range ( 33 ) of a characteristic curve specification for a dependence between the pumping current (I p ) and the pumping voltage (U p ); and
when the values lie outside the tolerance range ( 33 ) of the characteristic curve specification, then adjusting the lambda value (λ) based on the pumping voltage (U p ) of the lambda sensor rather than based on the pumping current (I p ) of the lambda sensor, and, in an adjusted state, measuring a further pumping current (I p ) of the lambda sensor and, for the self-alignment of the lambda sensor, the pumping current offset ( 32 ) is derived from at least one of: a further pumping current (U p ) for a compensation of a leakage current, a fault current of the lambda sensor and a cable harness belonging to the lambda sensor.

5. The exhaust gas system ( 10 ) of claim 4 , further comprising an exhaust gas catalyst ( 24 ) downstream of the first and second lambda sensors ( 18 , 20 ) for chemically converting combustion pollutants and a switching-type catalyst lambda sensor ( 28 ) is provided on an output side of the exhaust gas catalyst ( 24 ).

6. The exhaust gas system ( 10 ) of claim 5 , wherein the catalyst lambda sensor ( 28 ) is connected via an adjustment device to the first and second lambda sensors for self-alignment of the first and second lambda sensors as a function of a lambda adjustment intervention determined with the aid of the catalyst lambda sensor ( 28 ).

7. The exhaust gas system ( 10 ) of claim 6 , wherein a pre-catalyst broadband lambda sensor ( 26 ) is provided on an input side of the exhaust gas catalyst ( 24 ), and for self-alignment of the pre-catalyst broadband lambda sensor ( 26 ), the catalyst lambda sensor ( 28 ) is connected via an adjustment device to the pre-catalyst broadband lambda sensor ( 26 ) as a function of a lambda adjustment intervention determined with the aid of the catalyst lambda sensor ( 28 ).

8. The exhaust gas system ( 10 ) of claim 6 , wherein the pre-catalyst broadband lambda sensor ( 26 ) comprises a third self-alignment adjuster.

9. An exhaust gas system ( 10 ) for a motor vehicle propelled by an internal combustion engine, comprising
an exhaust gas catalyst ( 24 ) for chemically converting combustion pollutants of an internal combustion engine ( 12 );
a pre-catalyst broadband lambda sensor ( 26 ) provided on an input side of the exhaust gas catalyst ( 24 ); and
a catalyst lambda sensor ( 28 ) provided on the output side of the exhaust gas catalyst ( 24 ),
wherein the pre-catalyst broadband lambda sensor ( 26 ) comprises a self-alignment adjuster configured to:
measure a pumping current (I p ) of the lambda sensors provided for detecting a lambda value (λ);
measure a pumping voltage (U p ) of the lambda sensor correlating to the pumping current (I p );
check whether the measured pumping current (I p ) and the measured pumping voltage (U p ) lie within a specified tolerance range ( 33 ) of a characteristic curve specification for a dependence between the pumping current (I p ) and the pumping voltage (U p ); and
when the values lie outside the tolerance range ( 33 ) of the characteristic curve specification, then adjusting the lambda value (λ) based on the pumping voltage (U p ) of the lambda sensor rather than based on the pumping current (I p ) of the lambda sensor ( 18 , 20 ), and, in an adjusted state, measuring a further pumping current (I p ) of the lambda sensor and, for the self-alignment of the lambda sensor, the pumping current offset ( 32 ) is derived from at least one of: a further pumping current (U p ) for a compensation of a leakage current, a fault current of the lambda sensor and a cable harness belonging to the lambda sensor.

Assignees

• Porsche Ag

Inventors

• Klink Yannik
• Moellenhoff Tobias
• Weissmann Tobias

Classifications

• F01N2550/02

  Catalytic activity of catalytic converters · CPC title

• F01N11/007

  the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus · CPC title

• G01N33/0006

  Calibrating gas analysers · CPC title

• G01N27/419

  Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells · CPC title

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title