Control system and method for preventing stochastic pre-ignition in an engine

• US 9,127,604 B2
• Filed: 08/23/2011
• Issued: 09/08/2015
• Est. Priority Date: 08/23/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Davis, Richard Stephen
• Primary Examiner(s): Moulis, Thomas
• Assistant Examiner(s): DALLO, JOSEPH J
• Application Number:
  US13/215,826
• Publication Number:
  US 20130047956A1
• Time in Patent Office: 1,477 Days
• Field of Search: 12340611-40614, 123/406.16, 12340619-40621, 123/406.27, 123/406.29, 123/406.34, 12340637-40639, 701/104, 701/105, 701/111
• US Class Current: 1/1
• CPC Class Codes: F02D 2250/36 Control for minimising NOx emissions
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02P 5/152 dependent on pinking detecting or indicating knocks in internal-combustion engines G01L23/22
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A control system for an engine includes a spark module and a fuel module. The spark module advances spark timing of a cylinder R degrees past a spark limit for N consecutive cylinder firing events, and retards spark timing of the cylinder past the spark limit for M consecutive cylinder firing events after the N consecutive cylinder firing events. The fuel module supplies a rich fuel-air charge to the cylinder for the M consecutive cylinder firing events. According to the system, R is a real number greater than zero, N and M are integers greater than zero, and the spark limit is a control value used to limit an amount of spark advance to prevent spark-knock. A method for controlling an engine is also provided.

Claims

1. A control system for an engine, comprising:

an initiation module that selectively initiates a stochastic pre-ignition (SPI) process to induce SPI and that generates a request signal indicating initiation of the SPI process to induce SPI;

a spark module that, in response to receiving the request signal indicating the initiation of the SPI process to induce SPI, advances spark timing of a cylinder R degrees past a spark limit for N consecutive cylinder firing events, and retards spark timing of said cylinder past said spark limit for M consecutive cylinder firing events after said N consecutive cylinder firing events; and

a fuel module that supplies, in response to receiving the request signal indicating the initiation of the SPI process to induce SRI, a rich fuel-air charge to said cylinder for said M consecutive cylinder firing events,

wherein R is a real number greater than zero, N and M are integers greater than zero, and said spark limit is a control value used to limit an amount of spark advance to prevent spark-knock.

2. The control system of claim 1, wherein the initiation module determines when an engine speed is within a predetermined range, and wherein said spark module advances spark timing for a first one of said N consecutive cylinder firing events when said engine speed is within said predetermined range.

3. The control system of claim 1, wherein:

the initiation module determines when at least one of the following criteria is met;

(i) an engine torque is within a predetermined first range; and

(ii) a boost pressure is within a predetermined second range,

wherein said spark module advances spark timing for a first one of said N consecutive cylinder firing events when said at least one of said criteria is met.

4. The control system of claim 1, further comprising a detection module that detects when an SPI event occurs in said cylinder, and wherein said fuel module supplies a rich fuel-air charge to said cylinder for P consecutive cylinder firing events when said SPI event is detected, P being an integer greater than zero.

5. The control system of claim 1, wherein said M consecutive cylinder firing events begin on a next cylinder firing event of said cylinder after said N consecutive cylinder firing events.

6. The control system of claim 1, wherein, for each of a plurality of remaining cylinders, one cylinder at a time:

said spark module advances spark timing R degrees past said spark limit for another N consecutive cylinder firing events; and

said fuel module supplies another rich fuel-air charge for another M consecutive cylinder firing events after said N consecutive cylinder firing events.

7. The control system of claim 1, wherein a fuel-air equivalence ratio of said fuel-air charge is greater than 1.0 and less than 1.5.

8. The control system of claim 1, wherein N is an integer greater than zero and less than three.

9. The control system of claim 1, wherein M is an integer greater than zero and less than twenty.

10. The control system of claim 1, wherein said engine is one of a turbocharged engine and a supercharged engine.

11. A method for controlling an engine, comprising:

selectively initiating a stochastic pre-ignition (SPI) process to induce SPI;

generating a request signal indicating initiation of the SPI process to induce SPI;

in response to the request signal indicating the initiation of the SPI process to induce SPI, advancing spark timing of a cylinder R degrees past a spark limit for N consecutive cylinder firing events and retarding spark timing of said cylinder past said spark limit for M consecutive cylinder firing events after said N consecutive cylinder firing events; and

in response to the request signal indicating the initiation of the SPI process to induce SPI, supplying a rich fuel-air charge to said cylinder for said M consecutive cylinder firing events,

wherein R is a real number greater than zero, N and M are integers greater than zero, and said spark limit is a control value used to limit an amount of spark advance to prevent spark-knock.

12. The method of claim 11, further comprising:

determining when an engine speed is within a predetermined range; and

advancing spark timing of said cylinder for a first one of said N consecutive cylinder firing events when said engine speed is within said predetermined range.

13. The method of claim 11, further comprising:

determining when at least one of the following criteria is met;

(i) an engine torque is within a predetermined first range, and

(ii) a boost pressure is within a predetermined second range; and

advancing spark timing of said cylinder for a first one of said N consecutive cylinder firing events when said at least one of said criteria is met.

14. The method of claim 11, further comprising:

detecting when an SPI event occurs in said cylinder; and

supplying a rich fuel-air charge to said cylinder for P consecutive cylinder firing events when said SPI event is detected, P being an integer greater than zero.

15. The method of claim 11, wherein said M consecutive cylinder firing events begin on a next cylinder firing event of said cylinder after said N consecutive cylinder firing events.

16. The method of claim 11, further comprising:

advancing spark timing R degrees past said spark limit for another N consecutive cylinder firing events for each of a plurality of remaining cylinders, one cylinder at a time; and

supplying another rich fuel-air charge for another M consecutive cylinder firing events after said N consecutive cylinder firing events for each of said plurality of remaining cylinders, one cylinder at a time.

17. The method of claim 11, wherein a fuel-air equivalence ratio of said fuel-air charge is greater than 1.0 and less than 1.5.

18. The method of claim 11, wherein N is an integer greater than zero and less than three.

19. The method of claim 11, wherein M is an integer greater than zero and less than twenty.

20. The method of claim 11, wherein said engine is one of a turbocharged engine and a supercharged engine.