Method for correcting measured values of a sensor element

Patent metadata

Field	Value
Publication number	US-10533980-B2
Application number	US-201214350963-A
Country	US
Kind code	B2
Filing date	Sep 13, 2012
Priority date	Nov 11, 2011
Publication date	Jan 14, 2020
Grant date	Jan 14, 2020

Abstract

A measured value of a sensor element is obtained during repeatedly executed measuring periods for performing different measurements and for setting different operating states, the sensor element being electrically connected in a periodically alternating manner, in consecutive switching positions, in a predefined order, where at least one measurement for determining the measured value is performed repeatedly within a measuring period for determining individual values at predefined switching positions, the measured value being determined from the individual values. Using the switching position within the measuring period, the operating state of the sensor element preceding the individual measurement, and therefore, the influence of the preceding circuit configuration on the individual measured value, is known, and the individual values are correspondingly corrected. By correcting the individual values, the measured value determined from the individual values is also corrected.

First claim

What is claimed is:

1. A method for correcting individual measured values of a sensor element obtained over repeatedly executed measuring periods for performing different measurements and for setting different operating states, the sensor element is electrically connected by a circuit arrangement in a periodically alternating electrical manner, in consecutive switching positions, in a predefined order, the method comprising:
performing a measurement repeatedly within a measuring period, at predefined switching positions, the individual values thereby being determined at the predefined switching positions; and
correcting, by processing circuitry, the individual values as a function of the respective switching positions associated with respective ones of the individual values.

2. The method of claim 1 , wherein the correcting includes:
in a first phase, ascertaining an approximate value for the measured value;
in a learning phase:
determining deviations of the individual values from the approximate value and correlating the deviations to the respective switching positions associated with the respective individual values for which the respective deviations are determined; and
determining respective correction values for correcting the individual values for respective ones of the different switching positions; and

in an application phase, correcting the individual values using the respective correction values assigned to the respective switching positions of the respective individual values to be corrected.

3. The method of claim 2 , wherein, in the first phase, the approximate value is calculated as an average value of the individual values determined during one or more measuring periods.

4. The method of claim 2 , wherein the correction values used in the application phase for the respective switching positions are calculated as average values or as moving averages of the correction values determined for the respective switching positions in a plurality of measuring periods.

5. The method of claim 2 , wherein the first phase, the learning phase, and the application phase are executed simultaneously.

6. The method of claim 2 , wherein:
the sensor element is a wide-range lambda probe that includes a pump cell and a Nernst cell;
the measured value is a pump current for the pump cell of the wide-range lambda probe; and
in the first phase, the approximate value is calculated as an average value of the individual values calculated for switching positions where no polarization of the Nernst cell is to be expected in a preceding switching position.

7. A method for determining a combustion air ratio lambda in exhaust gas of an internal combustion engine, the method comprising:
obtaining a measured value of a pump current of a wide-range lambda probe; and
determining the combustion air ratio lambda based on the measured value;
wherein:
the wide-range lambda probe is electrically connected by a circuit arrangement in a periodically alternating electrical manner, in consecutive switching positions, in a predefined order; and
the obtaining of the measured value includes, during repeatedly executed measuring periods for performing different measurements and for setting different operating state, performing the following:
performing a pump current measurement repeatedly within a measuring period, at predefined switching positions, individual values thereby being determined at the predefined switching positions; and
correcting, by processing circuitry, the individual values as a function of the respective switching positions associated with respective ones of the individual values.

Assignees

• Ledermann Bernhard
• Belzner Ulrich
• Steinert Thomas
• Bosch Gmbh Robert

Inventors

• Ledermann Bernhard
• Belzner Ulrich
• Steinert Thomas

Classifications

• 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

• F01N2560/025

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

• G01N33/0006 Primary

  Calibrating gas analysers · CPC title

• F01N2900/1402

  Exhaust gas composition · CPC title

• G01N33/007

  Arrangements to check the analyser (calibrating gas analysers G01N33/0006) · CPC title