Exhaust gas sensor diagnosis and controls adaptation

Patent metadata

Field	Value
Publication number	US-9677491-B2
Application number	US-201313961628-A
Country	US
Kind code	B2
Filing date	Aug 7, 2013
Priority date	Aug 7, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

Methods and systems are provided reusing processed sensor data to identify multiple types of sensor degradation. In one example, a central peak of a distribution, such as a generalized extreme value distribution, of sensor readings is re-used to identify asymmetric sensor degradation and stuck in-range sensor degradation.

First claim

The invention claimed is:

1. An engine method, comprising:
indicating degradation of an air-fuel ratio sensor lean-rich (L-R) and rich-lean (R-L) asymmetry, as well as stuck in-range degradation, based on a central peak of a distribution of sensor reading differentials collected during selected engine operating conditions.

2. The method of claim 1 , wherein the sensor is an exhaust gas oxygen sensor, and wherein the distribution is a generalized extreme value distribution.

3. The method of claim 1 , wherein the selected engine operating conditions includes steady-state engine operation.

4. The method of claim 1 , wherein the central peak is based on a sum of an indicator function defined based on a size of a central bin of data distribution collected during the selected engine operating conditions from the air-fuel ratio sensor.

5. The method of claim 1 , wherein the sensor is positioned downstream of an emission control device.

6. The method of claim 1 , wherein the sensor is positioned downstream of another air-fuel ratio sensor, both sensors providing feedback for adjustment of fuel injection to an engine.

7. The method of claim 1 , further comprising storing a set code based on the indicated degradation in non-transitory memory of a controller.

8. The method of claim 1 , further comprising adjusting fuel injection independent of the air-fuel ratio sensor based on the central peak and correspondingly indicated degradation.

9. The method of claim 1 , further comprising adjusting fuel injection responsive to feedback from the air-fuel ratio sensor via an anticipatory controller when the air-fuel ratio sensor is not stuck in-range; and adjusting one or more parameters of the anticipatory controller responsive to a type of asymmetric sensor degradation.

10. The method of claim 9 , wherein the type of asymmetric sensor degradation includes a filter degradation or a delay degradation and wherein the one or more parameters includes a proportional gain.

11. The method of claim 10 , wherein the filter degradation is indicated by a degraded time constant being greater than an expected time constant and the delay degradation is indicated by a degraded time delay being greater than an expected time delay.

12. The method of claim 10 , further comprising adjusting a controller parameter responsive to both the delay degradation and the filter degradation.

13. The method of claim 10 , further comprising adjusting the proportional gain by a first amount responsive to the delay degradation and adjusting the proportional gain by a second, different, amount responsive to the filter degradation.

14. The method of claim 10 , further comprising adjusting a controller time constant responsive to the filter degradation and not adjusting the controller time constant responsive to the delay degradation.

15. The method of claim 10 , further comprising adjusting a controller time delay by a first amount responsive to the filter degradation and adjusting the controller time delay by a second, different, amount responsive to the delay degradation.

16. An engine method, comprising:
adjusting parameters of an anticipatory controller of an exhaust gas sensor by a first amount responsive to a delay degradation and adjusting parameters of the anticipatory controller by a second, different, amount responsive to a filter degradation, one of the delay and filter degradations based on a central peak of a generalized extreme value distribution of sensor reading differentials;
indicating the exhaust gas sensor is stuck in-range based on the central peak; and
adjusting fuel injection responsive to exhaust oxygen feedback from the anticipatory controller.

17. The method of claim 16 , wherein adjusting parameters of the anticipatory controller includes adjusting one or more of a proportional gain, an integral gain, a controller time constant, and a controller time delay.

18. The method of claim 17 , wherein adjusting parameters by the first amount responsive to the delay degradation includes adjusting the proportional gain, the integral gain, and the controller time delay based on a degraded time delay and not adjusting the controller time constant.

19. A system for a vehicle, comprising:
an engine including a fuel injection system;
an exhaust gas sensor coupled in an exhaust gas system of the engine, the exhaust gas sensor having a controller; and
a controller including instructions executable to adjust one or more parameters of the controller responsive to degradation of the exhaust gas sensor, wherein an amount of adjusting is based on a magnitude and type of degradation behavior of the exhaust gas sensor, the controller further including instructions to indicate degradation of the sensor responsive to a central peak of a generalized extreme value distribution of sensor readings.

20. The system of claim 19 , wherein the sensor is a downstream-positioned sensor.

Assignees

• Ford Global Tech Llc

Inventors

• Jammoussi Hassene
• Makki Imad Hassan
• Linenberg Mark Thomas
• Soriano Gladys G
• Behr Kenneth John

Classifications

• F02D41/1486

  with correction for particular operating conditions · CPC title

• F02D41/1456

  with sensor output signal being linear or quasi-linear with the concentration of oxygen · CPC title

• F02D2041/1423

  Identification of model or controller parameters · CPC title

• F02D2041/1431

  the system including an input-output delay · CPC title

• F02D41/1495 Primary

  Detection of abnormalities in the air/fuel ratio feedback system · CPC title