SYSTEM AND METHOD FOR DIAGNOSING A FAULT IN A THROTTLE AREA CORRECTION THAT COMPENSATES FOR INTAKE AIRFLOW RESTRICTIONS

• US 20150144098A1
• Filed: 02/05/2014
• Published: 05/28/2015
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: WORTHING, James L., BAUERLE, Paul A.
• Granted Patent: US 9,476,372 B2
• Time in Patent Office: Days
• US Class Current: 123/337
• CPC Class Codes: F02D 11/105 characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• CPC Class Codes: F02D 11/106 Detection of demand or actuation
• CPC Class Codes: F02D 11/107 Safety-related aspects
• CPC Class Codes: F02D 2011/108 with means for detecting or resolving a stuck throttle, e.g. when being frozen in a position
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A system according to the principles of the present disclosure includes a desired throttle area module, a correction factor module, a throttle control module, and an airflow compensation diagnostic module. The desired throttle area module determines a desired throttle area based on a driver input. The correction factor module determines a throttle area correction factor based on a difference between an estimated intake airflow and a measured intake airflow to compensate for a decrease in the measured intake airflow due to a flow restriction. The throttle control module determines a desired throttle position based on the desired throttle area and the throttle area correction factor. The airflow compensation diagnostic module diagnoses a fault in an amount of intake airflow compensation based on the throttle area correction factor.

Claims

1. A system comprising:

a desired throttle area module that determines a desired throttle area based on a driver input;

a correction factor module that determines a throttle area correction factor based on a difference between an estimated intake airflow and a measured intake airflow to compensate for a decrease in the measured intake airflow due to a flow restriction;

a throttle control module that determines a desired throttle position based on the desired throttle area and the throttle area correction factor; and

an airflow compensation diagnostic module that diagnoses a fault in an amount of intake airflow compensation based on the throttle area correction factor.

2. The system of claim 1 further comprising a learning residual module that determines a learning residual based on an average of N differences between the estimated intake airflow and the measured intake airflow at N different times, wherein:

the correction factor module determines the throttle area correction factor based on the learning residual; and

N is an integer greater than one.

3. The system of claim 2 wherein the correction factor module:

determines the throttle area correction factor based on the desired throttle area using a correction table; and

adjusts values in the correction table based on the learning residual.

4. The system of claim 2 wherein the airflow compensation diagnostic module diagnoses a fault in the amount of intake airflow compensation based on the throttle area correction factor and the learning residual.

5. The system of claim 4 wherein the airflow compensation diagnostic module determines that the amount of intake airflow compensation is greater than desired when:

the learning residual is less than a first value; and

the throttle area correction factor is greater than a second value.

6. The system of claim 5 wherein the first value is less than or equal to zero.

7. The system of claim 5 wherein:

the correction factor module maintains the throttle area correction factor within a predetermined limit; and

the airflow compensation diagnostic module determines the second value based on the predetermined limit.

8. The system of claim 5 wherein the correction factor module decreases the throttle area correction factor to zero when the airflow compensation diagnostic module determines that the amount of intake airflow compensation is greater than desired.

9. The system of claim 8 wherein the correction factor module:

determines a first correction factor based on the desired throttle area using a correction table;

the correction factor module determines a second correction factor by subtracting a predetermined value from a previous correction factor determined in a previous iteration; and

determines a present correction factor in a present iteration based on a minimum value of the first correction factor and the second correction factor.

10. The system of claim 9 wherein the correction factor module sets all values in the correction table equal to zero when the throttle area correction factor is less than or equal to zero.

11. A method comprising:

determining a desired throttle area based on a driver input;

determining a throttle area correction factor based on a difference between an estimated intake airflow and a measured intake airflow to compensate for a decrease in the measured intake airflow due to a flow restriction;

determining a desired throttle position based on the desired throttle area and the throttle area correction factor; and

diagnosing a fault in an amount of intake airflow compensation based on the throttle area correction factor.

12. The method of claim 11 further comprising:

determining a learning residual based on an average of N differences between the estimated intake airflow and the measured intake airflow at N different times; and

determining the throttle area correction factor based on the learning residual, wherein N is an integer greater than one.

13. The method of claim 12 further comprising:

determining the throttle area correction factor based on the desired throttle area using a correction table; and

adjusting values in the correction table based on the learning residual.

14. The method of claim 12 further comprising diagnosing a fault in the amount of intake airflow compensation based on the throttle area correction factor and the learning residual.

15. The method of claim 14 further comprising determining that the amount of intake airflow compensation is greater than desired when:

the learning residual is less than a first value; and

the throttle area correction factor is greater than a second value.

16. The method of claim 15 wherein the first value is less than or equal to zero.

17. The method of claim 15 further comprising:

maintaining the throttle area correction factor within a predetermined limit; and

determining the second value based on the predetermined limit.

18. The method of claim 15 further comprising decreasing the throttle area correction factor to zero after determining that the amount of intake airflow compensation is greater than desired.

19. The method of claim 18 further comprising:

determining a first correction factor based on the desired throttle area using a correction table;

determining a second correction factor by subtracting a predetermined value from a previous correction factor determined in a previous iteration; and

determining a present correction factor in a present iteration based on a minimum value of the first correction factor and the second correction factor.

20. The method of claim 19 further comprising setting all values in the correction table equal to zero when the throttle area correction factor is less than or equal to zero.