Engine control algorithm-cold start A/F modifier

• US 6,598,589 B2
• Filed: 03/26/2001
• Issued: 07/29/2003
• Est. Priority Date: 03/26/2001
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Frelund, Arthur R., Tolsma, Jay
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US09/817,916
• Publication Number:
  US 20020134356A1
• Time in Patent Office: 855 Days
• Field of Search: 123/435, 123/436, 123/685, 123/686, 123/491
• US Class Current: 123/435
• CPC Class Codes: F02D 41/064 at cold start F02D41/067 takes precedence
• CPC Class Codes: F02D 41/068 for warming-up
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02D 41/2432 Methods of calibration
• CPC Class Codes: F02D 41/2451 characterised by what is learned or calibrated

Abstract

A method and apparatus for controlling the amount of fuel used in combustion during open-loop run mode of a internal combustion engine. A lookup table calibrated to a fuel with a low driveability index is used to make a fueling decision for open-loop run mode. Then, at least one of the following indicators of fuel problems is monitored: the engine misfire detection system, the engine speed and the manifold absolute pressure. If any of these indicators detect a problem with the amount of fuel the engine is receiving, a fuel increase is calculated and implemented in one or more steps. A problem is indicated if an engine misfire is detected, the engine speed drops below a predetermined threshold value, or the manifold absolute pressure rises above a predetermined threshold value. The fuel increase is limited by a calculation based upon a fuel with a high driveability index.

Claims

1. A method of controlling an air-to-fuel ratio in an internal combustion engine during an open-loop run mode, comprising the steps of:

determining an air-to-fuel ratio based on a fuel with a low driveability index;

fueling the engine based on the air-to-fuel ratio;

monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio; and

increasing a level of fuel supplied to the engine to a maximum fuel level when the monitoring step detects a problem with the air-to-fuel ratio.

2. The method according to claim 1, wherein the step of fueling the engine to an air-to-fuel ratio based on a fuel with a low driveability index comprises the step of using a fuel with a driveability index from 1100-1150.

3. The method according to claim 1, wherein the step of monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises the steps of:

monitoring an engine misfire detection system; and

detecting the problem when an engine misfire is detected.

4. The method according to claim 1, wherein the step of monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises the steps of:

monitoring an engine misfire detection system;

monitoring an engine speed;

monitoring a manifold absolute pressure;

detecting the problem when one at least one of an engine misfire is detected, the engine speed drops below a predetermined threshold speed, and the manifold absolute pressure rises above a predetermined threshold pressure.

5. The method according to claim 1, wherein the step of monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises the steps of:

monitoring an engine speed; and

detecting the problem when the engine speed drops below a predetermined threshold speed.

6. The method according to claim 1, wherein the step of monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises the steps of:

monitoring a manifold absolute pressure; and

detecting the problem when the manifold absolute pressure rises above a predetermined threshold pressure.

7. The method according to claim 1, wherein the step of increasing the level of fuel supplied to the engine by an increase factor comprises the step of determining the level of fuel supplied based on a fuel with a high driveability index.

8. The method according to claim 7, wherein the step of determining the level of fuel supplied based on a fuel with a high driveability index comprises the step of using a fuel with a driveability index of 1250.

9. The method according to claim 1, wherein the step of increasing a level of fuel supplied to the engine to a maximum fuel level comprises the step of increasing the level of fuel supplied in more than one incremental step.

10. An apparatus for controlling an air-to-fuel ratio in an internal combustion engine during an open-loop run mode, comprising:

means for determining an air-to-fuel ratio based on a fuel with a low driveability index;

means for fueling the engine based on the air-to-fuel ratio;

means for monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio; and

means for increasing a level of fuel supplied to the engine to a maximum fuel level when the monitoring step detects a problem with the air-to-fuel ratio.

11. The apparatus according to claim 10, wherein the means for fueling the engine to an air-to-fuel ratio based on a fuel with a low driveability index comprises means for using a fuel with a driveability index from 1100-1150.

12. The apparatus according to claim 10, wherein the means for monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises:

means for monitoring an engine misfire detection system;

means for monitoring an engine speed;

means for monitoring a manifold absolute pressure;

means for detecting the problem when at least one of an engine misfire is detected, the engine speed drops below a predetermined threshold speed, and the manifold absolute pressure rises above a predetermined threshold pressure.

13. The apparatus according to claim 10, wherein the means for monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises:

means for monitoring an engine misfire detection system; and

means for detecting the problem when an engine misfire is detected.

14. The apparatus according to claim 10, wherein the means for monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises:

means for monitoring an engine speed; and

means for detecting the problem when the engine speed drops below a predetermined threshold speed.

15. The apparatus according to claim 10, wherein the means for monitoring at least one engine indicator to detect a problem with the air-to-fuel ratio comprises:

means for monitoring a manifold absolute pressure; and

means for detecting the problem when the manifold absolute pressure rises above a predetermined threshold pressure.

16. The apparatus according to claim 10, wherein the means for increasing the level of fuel supplied to the engine by an increase factor comprises means for determining the level of fuel supplied based on a fuel with a high driveability index.

17. The apparatus according to claim 16, wherein the means for determining the level of fuel supplied based on a fuel with a high driveability index comprises means for using a fuel with a driveability index of 1250.

18. The apparatus according to claim 10, wherein the means for increasing a level of fuel supplied to the engine to a maximum fuel level comprises means for increasing the level of fuel supplied in more than one incremental step.

19. An engine control system for controlling an air-to-fuel ratio in an engine, comprising:

a sensor that generates a signal upon occurrence of an engine misfire; and

a controller that determines an air-to-fuel ratio based on a fuel with a low driveability index, that regulates a fuel supply to the engine based on the air-to-fuel ratio, and that adjusts the fuel supply to a maximum fuel level in response to said signal.