Methods and systems for controlling on-board diagnostics

• US 8,909,413 B2
• Filed: 09/24/2010
• Issued: 12/09/2014
• Est. Priority Date: 09/24/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Mortensen, Anthony P.
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Sample, Jonathan L
• Application Number:
  US12/889,795
• Publication Number:
  US 20120078460A1
• Time in Patent Office: 1,537 Days
• Field of Search: None
• US Class Current: 701/29.8
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid
• CPC Class Codes: F02D 41/1495 Detection of abnormalities in the air/fuel ratio feedback system
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Embodiments provide systems and methods for using a feedback correction factor to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system. If the feedback correction factor is within a predetermined range, the vehicle is placed in a judging mode. If the feedback correction factor is outside a predetermined range, the vehicle is placed in a non-judging mode. Methods and systems for using an engine oil temperature to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system are disclosed. If an engine oil temperature, or predicted engine oil temperature, is below a predetermined temperature, the motor vehicle is placed in a non-judging mode. If an engine oil temperature, or predicted engine oil temperature, is above a predetermined temperature, the motor vehicle is placed in a judging mode.

Claims

1. A method of controlling an on-board diagnostic system of a motor vehicle, the method comprising:

receiving, by an electronic control unit, a signal from at least one sensor relating to a first air/fuel ratio of the engine;

determining, by the electronic control unit, a first air/fuel ratio;

calculating, by the electronic control unit, a feedback correction factor by dividing the first air/fuel ratio by an ideal air/fuel ratio;

retrieving, by the electronic control unit, a predetermined range associated with the feedback correction factor, wherein the electronic control unit is electronically connected to an on-board diagnostic system;

entering, by the on-board diagnostic system, a judging mode if the feedback correction factor is within the predetermined range, wherein the judging mode includes judging at least one on-board diagnostic item to determine whether a diagnostic problem is occurring; and

entering, by the on-board diagnostic system, a non-judging mode if the feedback correction factor is outside the predetermined range, wherein the non-judging mode includes ignoring at least one on-board diagnostic item and preventing a malfunction indicator from being activated.

2. The method of claim 1, wherein the predetermined range includes values between 0.5 and 1.5.

3. The method of claim 1, wherein the predetermined range includes values between 0.9 and 1.1.

4. The method of claim 1, wherein the on-board diagnostic system enters a judging mode if the feedback correction factor is below a threshold value.

5. The method of claim 1, wherein entering, by the on-board diagnostic system, the judging mode includes allowing a malfunction indicator to be activated based on the at least one on-board diagnostic item.

6. The method of claim 1, wherein the feedback correction factor is an average feedback correction factor.

7. The method of claim 1, further comprising:

determining, by the electronic control unit, a current engine oil temperature;

retrieving, by the electronic control unit, a predetermined engine oil temperature;

entering, by the on-board diagnostic system, a judging mode if the current engine oil temperature is above the predetermined engine oil temperature, wherein the judging mode includes judging at least one on-board diagnostic item to determine whether a diagnostic problem is occurring; and

entering, by the on-board diagnostic system, a non-judging mode if the current engine oil temperature is below the predetermined engine oil temperature, wherein the non-judging mode includes ignoring at least one on-board diagnostic item.

8. A method of controlling a motor vehicle, the method comprising:

receiving, by an electronic control unit, information from at least one sensor;

determining, by the electronic control unit, an average engine oil temperature over a period of time based on the information received from the sensor;

retrieving, by the electronic control unit, a predetermined engine oil temperature, wherein the electronic control unit is electronically connected to an on-board diagnostic system;

entering, by the on-board diagnostic system, a judging mode if the average engine oil temperature is above the predetermined engine oil temperature, wherein the judging mode includes judging at least one on-board diagnostic item to determine whether a diagnostic problem is occurring; and

entering, by the on-board diagnostic system, a non-judging mode if the average engine oil temperature is below the predetermined engine oil temperature, wherein the non-judging mode includes ignoring at least one on-board diagnostic item.

9. The method of claim 8, wherein the predetermined engine oil temperature is in the range between 70 degrees and 110 degrees.

10. The method of claim 8, wherein the predetermined engine oil temperature is approximately 90 F.

11. The method of claim 8, further comprising:

receiving, from an engine oil temperature sensor, a plurality of engine oil temperatures at periodic intervals.

12. An on-board diagnostic system for a motor vehicle, the system comprising:

an electronic control unit;

at least one sensor electronically connected to the electronic control unit, wherein the sensor is capable of sending at least one signal to the electronic control unit;

an on-board diagnostic system electronically connected to the electronic control unit, wherein the on-board diagnostic system is configured to judge at least one on-board diagnostic item to determine if a diagnostic problem is occurring;

wherein the electronic control unit evaluates a first signal received from the at least one sensor related to an air/fuel ratio and a second signal received from the at least one sensor related to a predicted engine oil temperature, the electronic control unit comparing at least one of the first signal and the second signal to a predetermined range; and

wherein, the judgments of the at least one on-board diagnostic item are prohibited based on the evaluation by the electronic control unit that the at least one of the first signal and the second signal is outside of the predetermined range.

13. The system of claim 12, wherein the electronic control unit determines an engine oil temperature based on the second signal from the sensor, and wherein judgments of the on-board diagnostic items are prohibited if the engine oil temperature is below a predetermined temperature.

14. The system of claim 13, wherein the predetermined temperature is based on an age of the motor vehicle.

15. The system of claim 12, wherein the evaluation of the electronic control unit includes determining a feedback correction factor, and wherein judgments of the on-board diagnostic items are prohibited if the feedback correction factor is outside the predetermined range.

16. The system of claim 15, wherein the predetermined range is 0.9 to 1.1.

17. The system of claim 12, wherein the electronic control unit determines an engine oil temperature based on the second signal from the sensor, and wherein the evaluation by the electronic control unit includes averaging the engine oil temperature, and wherein judgments of the on-board diagnostic items are prohibited if the average engine oil temperature is below a predetermined value.

18. The system of claim 12, wherein the evaluation of the electronic control unit includes determining an average feedback correction factor, and wherein judgments of the on-board diagnostic items are prohibited if the average feedback correction factor is outside the predetermined range.

19. The system of claim 12, wherein the electronic control unit determines an engine oil temperature based on the second signal from the sensor, and wherein judgments of the on-board diagnostic items system are allowed if the engine oil temperature is above a predetermined value.

20. The system of claim 19, wherein the evaluation of the electronic control unit includes determining a feedback correction factor, and wherein the feedback correction factor is outside of the predetermined range, and wherein the judgments of the on-board diagnostic items are allowed since the engine oil temperature is above a predetermined value.