Exhaust system having temperature sensor verification

• US 7,558,668 B2
• Filed: 11/30/2007
• Issued: 07/07/2009
• Est. Priority Date: 11/30/2007
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Ammineni, Chandini M., Withrow, Michael P.
• Primary Examiner(s): Vo; Hieu T
• Application Number:
  US11/987,490
• Publication Number:
  US 20090143953A1
• Time in Patent Office: 585 Days
• Field of Search: 701/114, 701/108, 701/109, 701/115, 602/74, 602/77, 602/86, 602/97, 603/01
• US Class Current: 701/114
• CPC Class Codes: F01N 11/002 the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
• CPC Class Codes: F01N 2560/06 the means being a temperature sensor
• CPC Class Codes: F01N 2590/08 for heavy duty applications, e.g. trucks, buses, tractors, locomotives
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An exhaust system is disclosed. The exhaust system has a first sensor disposed to sense a first temperature of an exhaust flow and a second sensor disposed to sense a second temperature of the exhaust flow. The exhaust system also has a controller in communication to receive from the first and second sensors signals indicative of the first and second temperatures. The controller is configured to compare the signals indicative of the first and second temperatures during exhaust system thermal equilibrium, to determine whether at least one of the signals indicative of the first and second temperatures is inaccurate based on the comparison, and to affect a system reaction if it is determined that at least one of the signals indicative of the first and second temperatures is inaccurate.

Claims

1. A machine, comprising:

a combustion engine configured to power operations of the machine; and

an exhaust system configured to manage an exhaust flow produced by the engine, the exhaust system comprising;

a first sensor disposed to sense a first temperature of the exhaust flow;

a second sensor disposed to sense a second temperature of the exhaust flow; and

a controller in communication to receive from the first and second sensors signals indicative of the first and second temperatures, the controller being configured to;

compare the signals indicative of the first and second temperatures during exhaust system thermal equilibrium;

determine whether at least one of the signals indicative of the first and second temperatures is inaccurate based on the comparison; and

affecting a system reaction if it is determined that at least one of the signals indicative of the first and second temperatures is inaccurate.

2. The machine of claim 1, wherein the system reaction includes at least one of logging a fault, alerting an operator, and implementing a precautionary exhaust system operating mode.

3. The machine of claim 1, wherein it is determined that at least one of the signals indicative of the first and second temperatures is inaccurate if the comparison indicates that first and second temperatures are not substantially the same.

4. The machine of claim 1, wherein the exhaust system thermal equilibrium occurs prior to starting the engine.

5. The machine of claim 1, wherein the exhaust system thermal equilibrium occurs while at least one of a rate of the exhaust flow is substantially constant and a speed of the engine is substantially constant.

6. The machine of claim 1, further including:

a exhaust treatment device arranged within the exhaust flow;

a regeneration device configured to heat the exhaust treatment device for a period of time in response to a command from the controller, wherein;

the first sensor is located at or near an inlet of the exhaust treatment device,

the second sensor is located at or near an outlet of the exhaust treatment device, and

the exhaust system thermal equilibrium occurs during the period of time.

7. An exhaust system, comprising:

a first sensor disposed to sense a first temperature of an exhaust flow;

a second sensor disposed to sense a second temperature of the exhaust flow;

a controller in communication to receive from the first and second sensors signals indicative of the first and second temperatures, the controller being configured to;

compare the signals indicative of the first and second temperatures during exhaust system thermal equilibrium;

determine whether at least one of the signals indicative of the first and second temperatures is inaccurate based on the comparison; and

affect a system reaction if it is determined that at least one of the signals indicative of the first and second temperatures is inaccurate.

8. The system of claim 7, wherein the system reaction includes at least one of logging a fault, alerting an operator, and implementing a precautionary exhaust system operating mode.

9. The system of claim 7, wherein it is determined that at least one of the signals indicative of the first and second temperatures is inaccurate if the comparison indicates that first and second temperatures are not substantially the same.

10. The system of claim 7, wherein the exhaust system thermal equilibrium occurs prior to starting an engine associated with the exhaust system.

11. The system of claim 7, wherein the exhaust system thermal equilibrium occurs while a rate of the exhaust flow is substantially constant.

12. The system claim 11, wherein the exhaust flow is produced by an engine and the exhaust system thermal equilibrium corresponds to a substantially constant engine speed.

13. The system of claim 7, further including:

a exhaust treatment device arranged within the exhaust flow;

a regeneration device configured to heat the exhaust treatment device for a period of time in response to a command from the controller, wherein;

the first sensor is located at or near an inlet of the exhaust treatment device,

the second sensor is located at or near an outlet of the exhaust treatment device, and

the exhaust system thermal equilibrium occurs during the period of time.

14. An exhaust system sensor verification method, comprising:

sensing a first and second temperatures of an exhaust flow;

providing indications of the first and second sensed temperatures;

comparing the indications of the first and second sensed temperatures during an exhaust system exhaust system thermal equilibrium;

determining whether at least one of the indications of the first and second sensed temperatures is inaccurate based on the comparison; and

affecting a system reaction if it is determined that at least one of the indications of the first and second sensed temperatures is inaccurate.

15. The method of claim 14, wherein the system reaction includes at least one of logging a fault, alerting an operator, and implementing a precautionary exhaust system operating mode.

16. The method of claim 14, wherein it is determined that the at least one of the indications of the first and second sensed temperatures is inaccurate if the comparison indicates that first and second sensed temperatures are not substantially the same.

17. The method of claim 14, wherein the exhaust system thermal equilibrium occurs prior to starting an engine associated with the exhaust system.

18. The method of claim 14, wherein the exhaust system thermal equilibrium occurs while a rate of the exhaust flow is substantially constant.

19. The method of claim 18, wherein the exhaust flow is produced by an engine and the exhaust system thermal equilibrium corresponds to a substantially constant engine speed.

20. The method of claim 14, further including:

heating an exhaust treatment device within the exhaust flow path for a period of time, wherein;

the first temperature is sensed at or near an inlet of the exhaust treatment device,

the second temperature is sensed at or near an outlet of the exhaust treatment, and

the exhaust system thermal equilibrium occurs during the period of time.