Method and device for operating a particle sensor

Patent metadata

Field	Value
Publication number	US-9880083-B2
Application number	US-201414893764-A
Country	US
Kind code	B2
Filing date	May 21, 2014
Priority date	May 28, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

The invention relates to a particle sensor ( 20 ) for determining a particle content in a gas flow, wherein the particle sensor ( 20 ) has, on the surface thereof, at least two interlocking interdigital IDE electrodes ( 23 ) and a heating element ( 26 ), separated from the IDE electrodes ( 23 ) by an insulating layer ( 21 ), by means of which heating element the particle sensor ( 20 ) can be heated in a regeneration phase and a soot load on the particle sensor can thus be removed, and by means of which particle sensor, in a diagnostic phase during the regeneration phase, a current is measured by intermittently applying a measurement voltage to the IDE electrodes ( 23 ) and, based on the chronological progression and size thereof, a functional inspection of the particle sensor ( 20 ) is carried out. During the regeneration phase, additional operating phases are introduced, in which, outside of the diagnostic phase ( 50 ), ions are specifically moved by intermittently applying specific voltage potentials different from zero volts to the IDE electrodes ( 23 ).

First claim

The invention claimed is:

1. A method for operating a particle sensor ( 20 ) in order to determine a particle content in a gas flow, wherein the particle sensor ( 20 ) comprises on its surface at least two interdigital IDE electrodes ( 23 ) engaging one another and a heating element ( 26 ), separated from the IDE electrodes ( 23 ) by an insulation layer and by which, in a regeneration phase, the particle sensor ( 20 ) is heated and a soot load on the particle sensor ( 20 ) is thereby be removed, and with which, in a diagnostic phase ( 50 ) during the regeneration phase, a current is measured by intermittently applying a measurement voltage to the IDE electrodes ( 23 ) and, with the aid of a profile and strength of the current as a function of time, a functional test of the particle sensor ( 20 ) is carried out, wherein, during the regeneration phase, additional operating phases are introduced in which, outside the diagnostic phase ( 50 ), ions are deliberately displaced by intermittently applying certain voltage potentials to the IDE electrodes ( 23 ); wherein in further operating phases during the regeneration phase, outside the diagnostic phase ( 50 ) and a polarization reversal phase ( 51 ), the electrical potentials of the IDE electrodes ( 23 ) are set to be equal to or greater than a heating element voltage ( 44 ) at the heating element ( 26 ).

2. The method as claimed in claim 1 , characterized in that, for a predeterminable time during the polarization reversal phase ( 51 ) preceding the diagnostic phase ( 50 ), a positive voltage potential is applied to the negative IDE electrode ( 23 ), the positive IDE electrode ( 23 ) being at a ground potential.

3. The method as claimed in claim 2 , characterized in that a duration which corresponds at most to the duration of the diagnostic phase ( 50 ) is selected for the polarization reversal phase ( 51 ).

4. The method as claimed in claim 1 , characterized in that, during these operating phases, the negative IDE electrode ( 23 ) is switched between a floating voltage potential and a voltage potential higher than the positive heating element voltage ( 44 ), and the positive IDE electrode ( 23 ) is operated during this time with a voltage potential equal to or higher than the positive heating element voltage ( 44 ).

5. The method as claimed in claim 1 , characterized in that the voltage potential at the positive IDE electrode ( 23 ) is between 8 and 13 volts.

6. The method as claimed in claim 1 , characterized in that the voltage potentials at the IDE electrodes ( 23 ), with the exception of the diagnostic phase ( 50 ) and the polarization reversal phase ( 51 ), are applied throughout the entire regeneration phase.

7. The method as claimed in claim 1 , characterized in that, in terms of the voltage potentials applied to the IDE electrodes ( 23 ) and duration, the additional operating phases within the regeneration phase of the particle sensor ( 20 ) are fixed in advance.

8. The method as claimed in claim 1 wherein the on-board diagnosis of the particle sensor ( 20 ), arranged in the exhaust gas system ( 17 ) of an internal combustion engine ( 1 ) configured as a diesel engine, performs on-board diagnosis of a particle filter.

9. The method as claimed in claim 1 , characterized in that the voltage potential at the positive IDE electrode ( 23 ) is more than 40 volts.

10. The method as claimed in claim 1 , characterized in that the voltage potentials at the IDE electrodes ( 23 ), with the exception of the diagnostic phase ( 50 ) and the polarization reversal phase ( 51 ), are applied intermittently.

11. The method as claimed in claim 1 , characterized in that, in terms of the voltage potentials applied to the IDE electrodes ( 23 ) and duration, the additional operating phases within the regeneration phase of the particle sensor ( 20 ) are adapted as a function of the present state of the IDE electrodes ( 23 ).

12. The method as claimed in claim 1 , wherein the on-board diagnosis of the particle sensor ( 20 ), arranged in the exhaust gas system ( 17 ) of an internal combustion engine ( 1 ) configured as a diesel engine, measures soot emissions.

13. The method as claimed in claim 1 , wherein the on-board diagnosis of the particle sensor ( 20 ), arranged in the exhaust gas system ( 17 ) of an internal combustion engine ( 1 ) configured as an Otto engine, performs on-board diagnosis of a particle filter.

14. The method as claimed in claim 1 , wherein the on-board diagnosis of the particle sensor ( 20 ), arranged in the exhaust gas system ( 17 ) of an internal combustion engine ( 1 ) configured as an Otto engine, measures soot emissions.

15. A device for operating a particle sensor ( 20 ) in order to determine a particle content in a gas flow, wherein the particle sensor ( 20 ) comprises on its surface at least two interdigital IDE electrodes ( 23 ) engaging one another and a heating element ( 26 ), which is separated from the IDE electrodes ( 23 ) by an insulation layer and by which, in a regeneration phase, the particle sensor ( 20 ) is heated by a control and evaluation unit ( 30 ) and a soot load on the particle sensor ( 20 ) is thereby removed, and with which, in a diagnostic phase ( 50 ) during the regeneration phase, a current is measured by intermittently applying a measurement voltage to the IDE electrodes ( 23 ) and, with the aid of a profile and strength of this current as a function of time, a functional test of the particle sensor ( 20 ) is carried out, characterized in that the control and evaluation unit ( 30 ) comprises an IDE supply unit ( 33 ), an IDE measurement unit ( 34 ), a heating element supply unit ( 35 ) and a temperature measurement unit ( 36 ), for carrying out the method as claimed in claim 1 .

16. A method for operating a particle sensor ( 20 ) in order to determine a particle content in a gas flow, wherein the particle sensor ( 20 ) comprises on its surface at least two interdigital IDE electrodes ( 23 ) engaging one another and a heating element ( 26 ), separated from the IDE electrodes ( 23 ) by an insulation layer and by which, in a regeneration phase, the particle sensor ( 20 ) is heated and a soot load on the particle sensor ( 20 ) is thereby be removed, and with which, in a diagnostic phase ( 50 ) during the regeneration phase, a current is measured by intermittently applying a measurement voltage to the IDE electrodes ( 23 ) and, with the aid of a profile and strength of the current as a function of time, a functional test of the particle sensor ( 20 ) is carried out, wherein, during the regeneration phase, additional operating phases are introduced in which, outside the diagnostic phase ( 50 ), ions are deliberately displaced by intermittently applying certain voltage potentials to the IDE electrodes ( 23 ); wherein for a predeterminable time during a polarization reversal phase ( 51 ) preceding the diagnostic phase ( 50 ), a positive voltage potential is applied to the negative IDE electrode ( 23 ), the positive IDE electrode ( 23 ) being at a ground potential.

17. The method as claimed in claim 16 , characterized in that a duration which corresponds at most to the duration of the diagnostic phase ( 50 ) is selected for the polarization reversal phase ( 51 ).

Assignees

• Bosch Gmbh Robert

Inventors

• Gaertner Benjamin
• Tiefenbach Andy
• Klenk Mathias

Classifications

• F01N2560/20

  Sensor having heating means · CPC title

• F01N2560/05

  the means being a particulate sensor · CPC title

• Y02T10/47

  Cross-Sectional Technologies · mapped topic

• F01N11/00

  Monitoring or diagnostic devices for exhaust-gas treatment apparatus · CPC title

• G01N15/0656 Primary

  using electric, e.g. electrostatic methods or magnetic methods (by investigating individual particles G01N15/1031, G01N15/12) · CPC title