Nox sensor diagnostic system and method

Patent metadata

Field	Value
Publication number	US-2016209383-A1
Application number	US-201514598906-A
Country	US
Kind code	A1
Filing date	Jan 16, 2015
Priority date	Jan 16, 2015
Publication date	Jul 21, 2016
Grant date	—

Abstract

Diagnostic processes for determining whether a NOx sensor is in a stuck-in-range failure mode may be performed when the NOx sensor reaches an operational temperature and before the oxygen pumps of the NOx sensor are activated and/or during operation. The processes may include interpreting values of a parameter indicative an amount of O2 and/or NOx measured by the NOx sensor. The processes include determining if the values of the parameter exceed a threshold value and indicating a failure of the NOx sensor responsive to the values not exceeding the threshold value. In some implementations, the processes may include increasing an amount of O2 in a chamber of the NOx sensor. Increasing the amount of O2 in the chamber of the NOx sensor may include deactivating an oxygen pump of the NOx sensor or reducing an amount of O2 removed via an oxygen pump of the NOx sensor.

First claim

What is claimed is:

1 . A system comprising:
a NO x sensor; and a controller configured to:
interpret one or more values of a parameter indicative an amount of O 2 and/or NO x measured by the NO x sensor responsive to the NO x sensor reaching an operational temperature, wherein an oxygen pump of the NO x sensor has not been activated;
determine if the one or more values of the parameter exceed a threshold value; and
indicate a failure of the NO x sensor responsive to the one or more values of the parameter not exceeding the threshold value.

2 . The system of claim 1 , wherein the controller is further configured to:
calculate a variation of the one or more values of the parameter indicative of the amount of O 2 and/or NO x measured by the NO x sensor; wherein determining if the one or more values of the parameter exceed a threshold value comprises determining if the calculated variation exceeds the threshold value; and wherein indicating the failure of the NO x sensor is responsive to the calculated variation not exceeding the threshold value.

3 . The system of claim 1 , wherein indicating the failure of the NO x sensor comprises setting a value for a parameter to a value indicating that the NO x sensor is in the stuck-in-range failure mode.

4 . The system of claim 1 , wherein indicating the failure of the NO x sensor comprises lighting a malfunction indicator lamp.

5 . The system of claim 1 , wherein the one or more values of the parameter indicative the amount of O 2 and/or NO x measured by the NO x sensor are based on a measured pumping current.

6 . The system of claim 1 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of 100 ppm.

7 . The system of claim 1 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of 500 ppm.

8 . The system of claim 1 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of less than 1000 ppm.

9 . A system comprising:
a NO x sensor; and a controller configured to:
increase an amount of O 2 in a chamber of the NO x sensor;
interpret one or more values of a parameter indicative an amount of O 2 and/or NO x measured by the NO x sensor;
determine if the one or more values of the parameter exceed a threshold value; and
indicate a failure of the NO x sensor responsive to the one or more values of the parameter do not exceed the threshold value.

10 . The system of claim 9 , wherein the controller is further configured to:
calculate a variation of the one or more values of the parameter indicative of the amount of O 2 and/or NO x measured by the NO x sensor; wherein determining if the one or more values of the parameter exceed a threshold value comprises determining if the calculated variation exceeds the threshold value; and wherein indicating the failure of the NO x sensor is responsive to the calculated variation not exceeding the threshold value.

11 . The system of claim 9 , wherein increasing the amount of O 2 in the chamber of the NO x sensor comprises deactivating an oxygen pump of the NO x sensor.

12 . The system of claim 9 , wherein increasing the amount of O 2 in the chamber of the NO x sensor comprises reducing an amount of O 2 removed via an oxygen pump of the NO x sensor.

13 . The system of claim 9 , wherein indicating the failure of the NO x sensor comprises setting a value for a parameter to a value indicating that the NO x sensor is in the stuck-in-range failure mode.

14 . The system of claim 9 , wherein indicating the failure of the NO x sensor comprises lighting a malfunction indicator lamp.

15 . The system of claim 9 , wherein the one or more values of the parameter indicative the amount of O 2 and/or NO x measured by the NO x sensor are based on a measured pumping current.

16 . The system of claim 9 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of less than 100 ppm.

17 . The system of claim 9 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of less than 500 ppm.

18 . A system comprising:
a NO x sensor; and a controller configured to:
interpret one or more values of a parameter indicative an amount of O 2 and/or NO x measured by the NO x sensor responsive to the NO x sensor reaching an operational temperature, wherein an oxygen pump of the NO x sensor has not been activated, or increasing an amount of O 2 in a chamber of the NO x sensor;
calculate a variation of the one or more values of the parameter indicative of the amount of O 2 and/or NO x measured by the NO x sensor;
determine if the calculated variation exceeds a threshold value; and
indicate a failure of the NO x sensor responsive to the calculated variation not exceeding the threshold value.

19 . The system of claim 18 , wherein the controller is further configured to:
store the calculated variation; calculate an average of a plurality of stored calculated variations; wherein determining if the calculated variation exceeds the threshold value comprises determining if the average of the plurality of stored calculated variations exceeds the threshold value; and wherein indicating the failure of the NO x sensor is responsive to the average of the plurality of stored calculated variations not exceeding the threshold value.

20 . The system of claim 18 , wherein indicating the failure of the NO x sensor comprises setting a value for a parameter to a value indicating that the NO x sensor is in the stuck-in-range failure mode or lighting a malfunction indicator lamp.

21 . The system of claim 18 , wherein the threshold value is a value indicative of an amount of O 2 and/or NO x of less than 1000 ppm.

Assignees

• Cummins Emission Solutions Inc

Inventors

• Gong Jinqian
• Hernandez-Gonzalez Sergio Manuel
• Shifatu-Badru Ruqiat O

Classifications

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• G01N33/0037 Primary

  NOx · CPC title

• G01M15/102

  by monitoring exhaust gases · CPC title

• Y02A50/20

  Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters · CPC title

• G01N33/007

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