System and method of controlling engine dilution rate using combustion stability measurer derived from the ionization signal

• US 7,213,573 B2
• Filed: 01/28/2005
• Issued: 05/08/2007
• Est. Priority Date: 11/01/2002
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Daniels, Chao F., Haskara, Ibrahim, Zhu, Guoming G.
• Primary Examiner(s): Cronin, Stephen K.
• Assistant Examiner(s): Castro, Arnold
• Application Number:
  US11/046,383
• Publication Number:
  US 20050126537A1
• Time in Patent Office: 830 Days
• Field of Search: 12340612-40617, 123/406.21, 123/406.22, 123/406.26, 123/406.27, 123/406.37, 123/406.43, 123/568.21, 123/406.28, 123/406.14, 701/108
• US Class Current: 123/406.28
• CPC Class Codes: F01N 2430/00 Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
• CPC Class Codes: F01N 3/2006 Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F02D 2041/141 using a feed-forward control element
• CPC Class Codes: F02D 2041/285 the sensor having a signal processing unit external to the engine control unit
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 35/021 using an ionic current sensor
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/0255 to accelerate the warming-up of the exhaust gas treating apparatus at engine start
• CPC Class Codes: F02D 41/1408 Dithering techniques
• CPC Class Codes: F02D 41/1482 Integrator, i.e. variable slope
• 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: F02D 41/2454 Learning of the air-fuel ratio control
• CPC Class Codes: F02M 26/01 Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages
• CPC Class Codes: F02P 17/02 Checking or adjusting ignition timing
• CPC Class Codes: F02P 17/10 Measuring dwell or antidwell time
• CPC Class Codes: F02P 17/12 Testing characteristics of the spark, ignition voltage or current testing of sparking plugs H01T13/60
• CPC Class Codes: F02P 2017/125 Measuring ionisation of combustion gas, e.g. by using ignition circuits
• CPC Class Codes: F02P 2017/128 : for knock detection
• CPC Class Codes: F02P 3/045 : for control of the dwell or anti dwell time
• CPC Class Codes: F02P 3/0453 : Opening or closing the primary coil circuit with semiconductor devices
• CPC Class Codes: F02P 3/051 : Opening or closing the primary coil circuit with semiconductor devices
• CPC Class Codes: F02P 5/1506 : with particular means during starting
• CPC Class Codes: F02P 5/1514 : with means for optimising the use of registers or of memories, e.g. interpolation
• CPC Class Codes: F02P 5/1523 : with particular laws of return to advance, e.g. step by step, differing from the laws of retard
• CPC Class Codes: F02P 5/1526 : with means for taking into account incorrect functioning of the pinking sensor or of the electrical means
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

This feature of the present invention comprises a system and method of controlling exhaust gas recirculation (EGR) based on a measure combustion stability measure. The combustion stability measure is obtained by determining the integration duration of the engine ionization signal, i.e., the crank angle at which the integral of the ionization signal reaches a specified percentage of its total. The present invention uses the integration duration to control the maximum EGR rate of the engine in a closed loop while maintaining the combustion stability of an internal combustion engine.

Claims

1. A method for controlling exhaust gas recirculation comprising:

sensing an ionization signal;

integrating said ionization signal to determine an ion integration value;

determining an integration duration, said integration duration comprising a crank angle at which an integral of said ionization signal obtains a specified percentage of said ion integration value;

comparing said integration duration to an optimized integration duration limit; and

controlling an exhaust gas recirculation rate such that said integration duration does not exceed said optimized integration duration limit.

2. The method of claim 1, further comprising:

determining a standard deviation of said integration duration; and

comparing said standard deviation of said integration duration to an integration duration standard deviation limit, wherein the step of controlling the exhaust gas recirculation rate comprises maintaining said standard deviation below said integration duration standard deviation limit.

3. The method of claim 2, wherein the step of controlling said exhaust gas recirculation irate comprises determining a desired integration duration.

4. The method of claim 3, wherein said desired integration duration is related to a speed and a load of the engine.

5. The method of claim 4, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

6. The method of claim 5, wherein the step of controlling the exhaust gas recirculation rate comprises operating the engine at said desired integration duration when said integration duration exceeds said desired integration duration.

7. The method of claim 1, further comprising the steps of determining a mean of said integration duration.

8. The method of claim 1, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

9. A method of controlling exhaust gas recirculation comprising:

sensing an ionization signal;

determining a combustion stability measure, said combustion stability measure being based on an integral of said ionization signal;

controlling an exhaust gas recirculation rate such that said combustion stability measure stays below a combustion stability limit, wherein said combustion stability measure comprises an integration duration, said integration duration comprising a crank angle at which said integral of said ionization signal obtains a specified percentage of a total value of said integral of said ionization signal.

10. The method of claim 9, wherein said combustion stability limit comprises a integration duration limit.

13. The method of claim 9, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

14. The method of claim 13, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

15. The method of claim 13, wherein said combustion stability limit comprises an integration duration limit.

16. The method of claim 10, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

11. A method of controlling exhaust gas recirculation comprising:

sensing an ionization signal;

determining a combustion stability measure, said combustion stability measure being based on an integral of said ionization signal;

controlling an exhaust gas recirculation rate such that said combustion stability measure stays below a combustion stability limit, wherein said combustion stability measure comprises a standard deviation of an integration duration, said integration duration comprising a crank angle at which said integral of said ionization signal obtains a specified percentage of a total value of said integral of said ionization signal.

12. The method of claim 11, wherein said combustion stability limit comprises an integration duration standard deviation limit.

17. The method of claim 11, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.

18. The method of claim 12, wherein the step of controlling the exhaust gas recirculation rate further comprises adjusting said exhaust gas recirculation rate for each of a plurality of cylinders of said engine.