Diesel oxidation catalyst (DOC) temperature sensor rationality diagnostic

• US 20080083271A1
• Filed: 03/17/2006
• Published: 04/10/2008
• Est. Priority Date: 04/12/2005
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: Chuan He, Guojun Shi, Jay Tolsma, Jose L. Deleon, Koji Sakumoto, Richard B. Jess
• Inventors: He, Chuan, Jess, Richard B., Sakumoto, Kouji, Tolsma, Jay, Shi, GuoJun, DeLeon, Jose L.
• Granted Patent: US 7,546,761 B2
• Time in Patent Office: Days
• US Class Current: 73/114.39
• CPC Class Codes: F01N 11/005 the temperature or pressure being estimated, e.g. by means of a theoretical model
• CPC Class Codes: F01N 2560/02 the means being an exhaust gas sensor
• CPC Class Codes: F01N 3/0231 using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• 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

A temperature sensor rationality control system for an exhaust treatment system having an oxidation catalyst includes an oxidation catalyst inlet temperature sensor that generates an inlet temperature signal and an oxidation catalyst outlet temperature sensor that generates an outlet temperature signal. A control module determines whether a difference based on the inlet temperature signal and the outlet temperature signal is below a difference threshold when an exhaust temperature is within a threshold range.

Claims

1. A temperature sensor rationality control system for an exhaust treatment system of a vehicle having an oxidation catalyst, comprising:

an oxidation catalyst inlet temperature sensor that generates an inlet temperature signal;

an oxidation catalyst outlet temperature sensor that generates an outlet temperature signal; and

a control module that determines whether a difference based on said inlet temperature signal and said outlet temperature signal is below a difference threshold when an exhaust temperature is greater than a first threshold temperature and is less than a second threshold temperature.

2. The temperature sensor rationality diagnostic of claim 1 wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when a plurality of vehicle operating parameters are within respective threshold ranges.

3. The temperature sensor rationality diagnostic of claim 2 wherein said vehicle operating parameters include engine running time, current fuel rate, exhaust mass flow, engine RPM, coolant temperature and no DPF regeneration occurring.

4. The temperature sensor rationality diagnostic of claim 2 wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when a plurality of vehicle operating parameters are within said respective threshold ranges for a threshold period of time.

5. The temperature sensor rationality diagnostic of claim 1 wherein said exhaust temperature is calculated based on at least one of an engine RPM, a primary fuel rate, an injection timing, a turbo boost level, a post fuel rate and an exhaust gas recirculation (EGR) value.

6. The temperature sensor rationality diagnostic of claim 1 wherein said difference is determined based on a delayed inlet temperature value.

7. The temperature sensor rationality diagnostic of claim 6 wherein said delayed inlet temperature value is determined based on at least one of a calibration factor, a previous delayed inlet temperature value and said inlet temperature signal.

8. The temperature sensor rationality diagnostic of claim 7 wherein said calibration factor is determined from a look-up table based on an exhaust flow rate and a fueling rate.

9. A method of determining a status of a temperature sensor of an exhaust treatment system of a vehicle having an oxidation catalyst, comprising:

generating an inlet temperature signal at an oxidation catalyst inlet using an inlet temperature sensor;

generating an outlet temperature signal at an oxidation catalyst outlet using an outlet temperature sensor;

calculating a difference based on said inlet temperature signal and said outlet temperature signal; and

determining a status of said inlet and outlet temperature sensors based on said difference when an exhaust temperature is greater than a first threshold temperature and is less than a second threshold temperature.

10. The method of claim 9 further comprising indicating a fault status when said difference is below a difference threshold.

11. The method of claim 9 further comprising determining whether a plurality of vehicle operating parameters are within respective threshold ranges, wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when said plurality of vehicle operating parameters are within said respective threshold ranges.

12. The method of claim 11 wherein said vehicle operating parameters include engine running time, current fuel rate, exhaust mass flow, engine RPM, coolant temperature and no DPF regeneration occurring.

13. The method of claim 11 wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when said plurality of vehicle operating parameters are within said respective threshold ranges for a threshold period of time.

14. The method of claim 9 wherein said exhaust temperature is calculated based on at least one of an engine RPM, a primary fuel rate, an injection timing, a turbo boost level, a post fuel rate and an exhaust gas recirculation (EGR) value.

15. The method of claim 9 wherein said difference is determined based on a delayed inlet temperature value.

16. The method of claim 15 wherein said delayed inlet temperature value is determined based on at least one of a calibration factor, a previous delayed inlet temperature value and said inlet temperature signal.

17. The method of claim 16 wherein said calibration factor is determined from a look-up table based on an exhaust flow rate and a fueling rate.

18. A method of diagnosing an operating condition of a temperature sensor of an exhaust treatment system of a vehicle having an oxidation catalyst, comprising:

generating an inlet temperature signal at an oxidation catalyst inlet using an inlet temperature sensor;

generating an outlet temperature signal at an oxidation catalyst outlet using an outlet temperature sensor;

determining a delayed inlet temperature signal based on said inlet signal and characteristics of said oxidization catalyst;

calculating a difference based on said delayed inlet temperature signal and said outlet temperature signal; and

determining a status of said inlet and outlet temperature sensors based on said difference when an exhaust temperature is greater than a first threshold temperature and is less than a second threshold temperature.

19. The method of claim 18 further comprising indicating a fault status when said difference is below a difference threshold.

20. The method of claim 19 further comprising determining whether a plurality of vehicle operating parameters are within respective threshold ranges, wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when said plurality of vehicle operating parameters are within said respective threshold ranges.

21. The method of claim 20 wherein said vehicle operating parameters include engine running time, current fuel rate, exhaust mass flow, engine RPM, coolant temperature and no DPF regeneration occurring.

22. The method of claim 20 wherein said exhaust temperature is greater than said first threshold temperature and is less than said second threshold temperature when said plurality of vehicle operating parameters are within said respective threshold ranges for a threshold period of time.

23. The method of claim 18 wherein said exhaust temperature is calculated based on at least one of an engine RPM, a primary fuel rate, an injection timing, a turbo boost level, a post fuel rate and an exhaust gas recirculation (EGR) value.

24. The method of claim 18 wherein said delayed inlet temperature value is determined based on at least one of a calibration factor, a previous delayed inlet temperature value and said inlet temperature signal.

25. The method of claim 24 wherein said calibration factor is determined from a look-up table based on an exhaust flow rate and a fueling rate.