Exhaust gas control using a spark plug ionization signal

• US 6,980,903 B2
• Filed: 06/11/2003
• Issued: 12/27/2005
• 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., Zhu, Guoming G.
• Primary Examiner(s): Argenbright, Tony M.
• Assistant Examiner(s): Hoang, Johnny H.
• Application Number:
  US10/458,691
• Publication Number:
  US 20040088102A1
• Time in Patent Office: 930 Days
• Field of Search: 701102-111, 123/406.44, 123/406.48, 123/406.59, 123/406.19, 123/406.21, 123/406.23, 731/181, 731/16, 731/172, 731/173
• US Class Current: 701/108
• 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 41/005 according to engine operating conditions
• 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 method and apparatus to reduce NOx emissions in an internal combustion engine. This feature of the present invention uses a closed loop control of the exhaust gas re-circulation to provide the engine with the either EGR MBT timing or a knock limited timing to yield the minimum NOx emission with maximum fuel economy benefits associated with exhaust gas re-circulation. When the exhaust gas re-circulation rate is not knock limited, the engine sets its exhaust gas re-circulation rate to an optimal rate at which the engine runs at the exhaust gas re-circulation minimum best time for best torque spark timing limit. When the exhaust gas re-circulation rate is knock limited, the engine sets its exhaust gas re-circulation rate to a knock limited rate at which the engine runs at a retarded MBT spark timing limit. The engine uses calibratable MBT timing criteria to determine the retarded MBT spark timing limit.

Claims

1. A method of controlling exhaust gas re-circulation, comprising using a measurement of minimum best time for best torque timing to control exhaust gas re-circulation, said measurement of minimum best time for best torque timing comprising a spark timing at which maximum torque occurs for a given set of engine operating conditions, wherein said step of using minimum best time for best torque timing criterion to control exhaust gas re-circulation further comprises the steps of:

running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited; and

running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limited.

2. A method of controlling exhaust gas re-circulation comprising using a measurement of minimum best time for best torque timing to control exhaust gas re-circulation, said measurement of minimum best time for best torque timing comprising a spark timing at which maximum torque occurs for a given set of engine operating conditions wherein said step of using minimum best time for best torque timing criterion to control exhaust gas re-circulation further comprises the steps of:

running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited; and

running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limit, wherein said step of running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limited comprises setting the exhaust gas re-circulation rate to a knock limited exhaust gas re-circulation rate.

3. The method of controlling exhaust gas re-circulation according to claim 2 wherein said step of setting the exhaust gas re-circulation rate to a knock limited exhaust gas re-circulation rate, comprises:

increasing the exhaust gas re-circulation rate if said measurement of minimum best time for best torque dining is below a first limit; and

decreasing the exhaust gas re-circulation rate if said measurement of minimum best time for best torque timing is greater than said first limit.

4. A method of controlling exhaust gas re-circulation comprising using a measurement of minimum best time for best torque timing to control exhaust gas re-circulation, said measurement of minimum best time for best torque timing comprising a spark timing at which maximum torque occurs for a given set of engine operating conditions, wherein said step of using minimum best time for best torque timing criterion to control exhaust gas re-circulation further comprises the steps of:

running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited; and

running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limit, wherein said step of running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited comprises setting the exhaust gas re-circulation rate to an optimal exhaust gas re-circulation rate.

5. The method of controlling exhaust gas re-circulation according to claim 4 wherein said step of setting the exhaust gas re-circulation rate to an optimal exhaust gas re-circulation rate further comprises the steps of:

increasing the exhaust gas re-circulation rate if a minimum best time for best torque timing is below a second limit; and

decreasing the exhaust gas re-circulation rate if said minimum best time for best torque timing is greater than said second limit.

6. A method of controlling exhaust gas re-circulation comprising using a measurement of minimum best time for best torque timing to control exhaust gas re-circulation, said measurement of minimum best time for best torque timing comprising a spark timing at which maximum torque occurs for a given set of engine operating conditions, wherein said step of using minimum best time for best torque timing criterion to control exhaust gas re-circulation further comprises the steps of:

running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited, wherein said step of running an engine at an exhaust gas re-circulation minimum best time for best torque spark timing when said engine is not knock limited comprises setting the exhaust gas re-circulation rate to an optimal exhaust gas re-circulation rate; and

running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limit, wherein said step of running an engine at an offset from said exhaust gas re-circulation minimum best time for best torque spark timing when said engine is knock limited comprises setting the exhaust gas re-circulation into to a knock limited exhaust gas re-circulation rate.

7. The method of controlling exhaust gas re-circulation according to claim 6 wherein said step of setting the exhaust gas re-circulation rate to a knock limited exhaust gas re-circulation rate, comprises:

increasing the exhaust gas re-circulation rate if said measurement of minimum best time for best torque timing is below a first limit; and

decreasing the exhaust gas re-circulation rate if said measurement of minimum best time for best torque timing is greater than said first limit; and

wherein said step of setting the exhaust gas re-circulation rate to an optimal exhaust gas re-circulation rate further comprises the steps of;

increasing the exhaust gas re-circulation rate if a minimum best time for best torque timing is below a second limit; and

decreasing the exhaust gas re-circulation rate if said minimum best time for best torque timing is greater than said second limit.

8. The method of controlling exhaust gas re-circulation according to claim 7 further comprising the step of mapping a maximum exhaust re-circulation rate with a satisfactory combustion stability criterion.

9. The method of controlling exhaust gas re-circulation according to claim 7 further comprising the step of comparing the exhaust re-circulation rate with a default exhaust re-circulation rate generated from current engine operating conditions.

10. The method of controlling exhaust gas re-circulation according to claim 7 further comprising the step of:

resetting the exhaust gas re-circulation rate if the exhaust gas re-circulation rate is saturated; and

converting the exhaust gas re-circulation rate into a valve opening.

11. The method of controlling exhaust gas re-circulation according to claim 7 further comprising the steps of:

mapping a maximum exhaust re-circulation rate with a satisfactory combustion stability criterion;

comparing the exhaust re-circulation rate with a default exhaust re-circulation rate generated from current engine operating conditions;

resetting the exhaust gas re-circulation rate if the exhaust gas re-circulation rate is saturated; and

converting the exhaust gas re-circulation rate into a valve opening.

12. An exhaust gas re-circulation controller comprising:

a closed loop, whereby exhaust gas re-circulation is controlled by said closed loop, wherein said closed loop comprises;

a first table comprising a map of exhaust gas re-circulation rates at specific operating conditions;

a gain and error generator having an input operably connected to an output of said first table;

a proportional and integral controller having an input operably connected to an output of said gain and error generator;

a second table comprising a map of maximum exhaust gas re-circulation rates and stability criterion; and

a summer having a first input operably connected to an output of said proportional and integral controller, a second input operably connected to an output of said second table, and an output operably connected to an input of said second table.

13. The exhaust gas re-circulation controller according in claim 12 wherein said closed loop further comprises:

a saturation manager, having an output operably connected to an input of said proportional and integral controller.

14. The exhaust gas re-circulation controller according to claim 12 wherein said closed loop further comprises:

a rate adaptor operably connected between said output of said summer and said input of said second table.

15. The exhaust gas re-circulation controller according to claim 12 wherein said closed loop further comprises:

an exhaust gas re-circulation valve metering controller having an input operably connected to said saturation manager.

16. The exhaust gas re-circulation controller according in claim 12 wherein said closed loop further comprises:

a saturation manager, having an output operably connected to an input of said proportional and integral controller;

a rate adaptor operably connected between said output of said summer and said input of said second table; and

an exhaust gas re-circulation valve metering controller having an input operably connected to said saturation manager.

17. The exhaust gas re-circulation controller according to claim 12 wherein said first table is a minimum best unit for best torque limit table and said second table is an exhaust gas re-circulation rate table.

18. The exhaust gas re-circulation controller according to claim 16 wherein said first table is a minimum best time for best torque limit table and said second table is an exhaust gas re-circulation rate table.