Ignition diagnosis and combustion feedback control system using an ionization signal

• US 7,134,423 B2
• Filed: 06/11/2003
• Issued: 11/14/2006
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• 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): Cronin, Stephen K.
• Assistant Examiner(s): Castro, Arnold
• Application Number:
  US10/458,704
• Publication Number:
  US 20040084018A1
• Time in Patent Office: 1,252 Days
• Field of Search: 123/406.14, 123/406.21, 123/406.47, 123/406.48
• US Class Current: 123/406.14
• 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 an ignition diagnostics and feedback control system based upon detected ionization current in an individual cylinder. The system is divided into two subsystems: an ignition diagnostics subsystem and an ignition feedback control system subsystem. The ignition diagnostics subsystem comprises an ignition system diagnostics, a misfire detector, a knock detector, and a robust multi-criteria minimum timing for best torque MBT timing estimator. The ionization feedback control subsystem comprises five main subsystems: a closed loop cold start retard spark control using ionization feedback, a closed loop MBT timing control using ionization feedback, a closed-loop individual cylinder air to fuel ratio balancing control system, an optimal wide open throttle air/fuel ratio control, and an exhaust gas control using a spark plug ionization signal.

Claims

1. An ignition diagnostics and feedback control system comprising:

an ignition diagnostics subsystem; and

an ignition feedback control subsystem operably connected to said ignition diagnostics subsystem, wherein said ignition feedback control subsystem comprises;

a closed loop cold start retard spark controller using ionization feedback having an input operably connected to said ionization signal;

a closed loop MBT timing controller using ionization feedback having a misfire input operably connected to said misfire detector output, a knock input operably connected to said knock detector output and an output;

an individual cylinder air to fuel ratio control system having an input operably to an output of said multi-criteria MBT timing estimator;

an optimal wide open throttle air to fuel ratio controller having an input operably connected to said ionization signal; and

an exhaust gas re-circulation controller having an input operably connected to said output of said closed loop MBT timing controller.

2. The ignition diagnostics and feedback control system according to claim 1 wherein said ignition diagnostics subsystem comprises:

an ignition systems diagnostics detector having an input operably connected to an ionization signal;

a misfire detector having an input operably connected to said ionization signal;

a knock detector having an input operably connected to said ionization signal; and

a multi-criteria MBT timing estimator having an input operably connected to said ionization signal.

3. The ignition diagnostics and feedback control system according to claim 2 wherein said multi-criteria MBT timing estimator comprises:

a controller;

memory operably connected to said controller;

software stored in said memory; and

an ionization detection unit operably connected to said controller, wherein said software comprises instructions to determine what case an ionization signal waveform fits; and

instructions to calculate MBT timing.

4. The ignition diagnostics and feedback control system according to claim 1 wherein said a closed loop cold start retard spark controller using ionization feedback comprises:

an error and gain generator having a plurality of inputs and outputs;

an integration controller having a plurality of inputs operably connected to said plurality of outputs of said error and gain generator;

a summer having a first input operably connected to an output of said integration controller; and

a feedback controller having an output operably connected to a second input of said summer and a first input operably connected to an output of said summer.

5. The ignition diagnostics and feedback control system according to claim 1 wherein said closed loop MBT timing controller using ionization feedback, comprises:

a proportional and integral controller;

a knock limit manager operably connected to said proportional and integral controller;

a misfire limit manager operably connected to said proportional and integral controller; and

a saturation manager operably connected to said proportional and integral controller.

6. The ignition diagnostics and feedback control system according to claim 1 wherein said individual cylinder air to fuel ratio balancing control system, comprises:

an ionization detection circuit,

a controller operably connected to said ionization detection circuit;

memory; and

software stored in said memory, wherein said software comprises instructions which control a cylinder'"'"'s air to fuel ratio using timing criterion, wherein said instructions which control a cylinder'"'"'s air to fuel ratio using timing criterion comprise;

calculating a mean timing coefficient;

calculating a timing coefficient error;

integrating said timing coefficient error;

calculating a raw fuel trim coefficient;

rescaling said raw fuel trim coefficient;

updating a feedforward look-up table based upon the current engine operating conditions; and

calculating a final fueling coefficient.

7. The ignition diagnostics and feedback control system according to claim 1 wherein said optimal wide open throttle air to fuel ratio controller comprises:

an ionization detection circuit;

a controller operably connected to said ionization detection circuit;

memory; and

software stored in said memory, wherein said software comprises instructions which use an ionization signal to optimize an air to fuel ratio of a combustion mixture, wherein said software further comprises instructions to calculate a valley value and a second peak value from said ionization signal.

8. The ignition diagnostics and feedback control system according to claim 1 wherein said exhaust gas recirculation controller comprises a closed loop, whereby exhaust gas re-circulation is controlled by said closed loop.

9. A method of improving fuel economy and decreasing emissions in an engine comprising the steps of:

calculating ignition disenostics; and

controlling an engine air to fuel ratio, exhaust gas recirculation and spark timing, wherein said step of calculating ignition diagnostics comprises;

diagnosing an ignition system using an ionization signal;

detecting a misfire using said ionization signal;

detecting a knock using said ionization signal; and

estimating MBT timing using said ionization signal.

10. The method of improving fuel economy and decreasing emissions in an engine according to claim 9 wherein said step of controlling an engine air to fuel ratio, exhaust gas recirculation and spark timing comprises:

reducing hydrocarbon emission during a cold start;

using estimated MBT timing criterion and ignition diagnostics to control the engine ignition timing;

balancing individual cylinder air to fuel ratios;

optimizing an air to fuel ratio of a combustion mixture; and

using MBT criteria to control the exhaust gas recirculation.

11. The method of improving fuel economy and decreasing emissions in an engine according to claim 9 wherein said step of estimating MBT timing comprises combining one or more of a maximum flame acceleration point, a maximum heat release location and a second peak location.

12. A method of improving fuel economy and decreasing emissions in an engine comprising the steps of:

calculating ignition diagnostics; and

controlling an enaine air to fuel ratio, exhaust gas recirculation and spark timing, wherein said step of controlling an engine air to fuel ratio, exhaust gas recirculation and spark timing comprises;

reducing hydrocarbon emission during a cold start;

using estimated MBT timing criterion and ignition diagnostics to control the engine ignition timing;

balancing individual cylinder air to fuel ratios;

optimizing an air to fuel ratio of a combustion mixture; and

using MBT criterion to control the exhaust gas recirculation.

13. The method of improving fuel economy and decreasing emissions in an engine according to claim 12 wherein said step of reducing hydrocarbon emission during a cold start comprises heating up a catalyst quickly by retarding a spark time to raise an exhaust temperature.

14. The method of improving fuel economy arid decreasing emissions in an engine according to claim 12 wherein said step of using estimated MBT timing criterion and ignition diagnostics to control engine ignition timing, comprises the following steps:

calculating said MBT timing criterion, and said ignition diagnostics, wherein said ignition diagnostics comprises knock information and misfire information;

generating an error signal by comparing said MBT criterion with a reference signal;

outputting said error signal to a controller;

producing a proportional error signal by multiplying said error signal by a proportional gain;

producing an integrated error signal by integrating said error signal with an integral gain;

resetting said integrated error signal if an engine is knock or misfire limited;

outputting a feedforward signal; and

outputting a timing signal by summing said proportional error signal, said integrated error signal and said feedforward signal.

15. The method of improving fuel economy and decreasing emissions in an engine according to claim 12 wherein said step of balancing individual cylinder air to fuel ratios comprises inputting at least one timing coefficient.

16. The method of improving fuel economy and decreasing emissions in an engine according to claim 12 wherein said step of optimizing an air to fuel ratio of a combustion mixture, comprises the step of maximizing a second peak and a valley of an ionization signal.

17. The method of improving fuel economy and decreasing emissions in an engine according to claim 12 wherein said step of using MBT criteria to control exhaust gas recirculation comprises:

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

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