Method for reducing pin count of an integrated coil with driver and ionization detection circuit by multiplexing ionization and coil charge current feedback signals

• US 6,951,201 B2
• Filed: 06/11/2003
• Issued: 10/04/2005
• 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: Wang, Bruce, Zhu, Guoming G., Nation, Michael T., Gould, Kenneth L., Moran, Kevin D., Huberts, Garlan J.
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US10/458,627
• Publication Number:
  US 20040084021A1
• Time in Patent Office: 846 Days
• Field of Search: 123/630, 123/652, 123/406.27, 73/350.8
• US Class Current: 123/406.27
• 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 35/027 using knock sensors
• 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 41/2454 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

In a first preferred embodiment, the present feature of the invention multiplexes both the ionization and driver current feedback signals into one signal, thus reducing cost and making coil packaging easier. The multiplexed signal first outputs the ionization detection signal and then replaces the ionization signal with the charge current feedback signal when the charge command V_in is enabled. In other words, the multiplexed feedback signal outputs the ionization feedback signal and switches to the charge current feedback signal when the charge command V_in is active. In a second preferred embodiment, the present feature of the invention comprises a method and apparatus to multiplex the ignition driver gate signal with both the ignition coil charge current feedback signal and the ionization signal, thus reducing the package pin count by two.

Claims

1. An integrated ignition system, comprising:

an ignition coil comprising a primary winding with a first and a second end and a secondary winding with a first and a second end;

a coil driver circuit having a first end operably connected to said second end of said primary winding;

an ionization detection circuit having at least two inputs and an output, wherein a first input is operably connected to said second end of said primary winding, and a second input is operably connected to said first end of said secondary winding;

a switch having at least two inputs and an output, wherein a first input is operably connected to said output of said ionization detection circuit, a second input is operably connected to a second end of said coil driver circuit, whereby said output of said switch is multiplexed between an ionization signal and a charge current feedback signal; and

an ignition plug operably connected between said second end of said secondary winding and ground.

2. The integrated ignition system according to claim 1 further comprising an amplifier having an input and an output, wherein said input is operably connected to said output of said switch.

3. The integrated ignition system according to claim 2, wherein said integrated ignition system further comprises:

a charge gate input pin operably connected to a command input of said coil driver circuit;

a ground pin;

a battery supply pin operably connected to said first end of said primary winding; and

an output pin operably connected to said output of said amplifier.

4. The integrated ignition system according to claim 1, wherein said ionization detection circuit comprises:

a capacitor having a first end operably connected to said second end of said primary winding; and

a current mirror having a first terminal operably connected to said first end of said secondary winding and a second terminal operably connected to said first end of said capacitor.

5. A method of detecting an ionization signal and a driver current feedback signal, comprising the step of multiplexing the ionization signal and the driver current feedback signal, wherein said step of multiplexing the ionization signal and the driver current feedback signal comprises the steps of:

outputting the ionization signal;

charging an ignition coil by enabling a charge command;

outputting the charge current feedback signal while a charge command signal is enabled;

disabling said charge command signal;

igniting an air/fuel mixture;

outputting an ignition current signal;

combusting said air/fuel mixture;

outputting said ionization signal; and

combining said ionization signal, said charge current feedback signal and said ignition current signal.

6. The method according to claim 5 wherein said step of combining said ionization signal, said charge current feedback signal and said ignition current signal comprises outputting said ionization signal, said charge current feedback signal and said ignition current signal on a same output pin.

7. The method according to claim 5 wherein said step of outputting a charge current feedback signal while said charge command signal is enabled comprises switching between said ionization signal and said charge current feedback signal when said charge command signal is enabled.

8. A method of detecting an ionization signal and a driver current feedback signal, comprising the step of multiplexing the ionization signal and the driver current feedback signal, wherein said step of multiplexing the ionization signal and the driver current feedback signal comprises the steps of:

outputting an ionization signal;

enabling a charge command signal, whereby a primary winding of an ignition coil is charged;

outputting a charge current feedback signal while said charge command is enabled;

disabling said charge command signal; and

outputting said ionization signal after said charge command signal is disabled.

9. An integrated ignition system, comprising:

an ignition coil comprising a primary winding having a first and a second end and a secondary winding having a first and a second end;

a coil driver circuit having a first end operably connected to said second end of said primary winding;

a difference comparator having an output operably connected to an input of said coil driver circuit;

an ionization detection circuit having at least two inputs and an output, wherein a first input is operably connected to said second end of said primary winding, and a second input is operably connected to said first end of said secondary winding;

a switch having at least two inputs and an output, wherein a first input is operably connected to said output of said ionization detection circuit, a second input is operably connected to a second end of said coil driver circuit, whereby said output of said switch is multiplexed between an ionization signal and a charge current feedback signal;

a first amplifier having an input and an output, wherein said input is operably connected to said output of said switch and said output is operably connected to a first input of said difference comparator;

a second amplifier having an input and an output, wherein said input is operably connected to said output of said switch and said output is operably connected to a second input of said difference comparator;

an ignition plug operably connected between said second end of said secondary winding and ground; and

a charge gate signal generator having an output operably connected to said output of said first amplifier.

10. The integrated ignition system according to claim 9 further comprising:

a first resistor operably connected between said output of said first amplifier and said output of said charge gate signal generator;

a second resistor operably connected between said output of said charge gate signal generator and ground; and

a third resistor operably connected between said output of said second amplifier and ground.

11. The integrated ignition system according to claim 10 wherein said ionization detection circuit comprises:

a capacitor having a first end operably connected to said second end of said primary winding; and

a current mirror having a first terminal operably connected to said first end of said secondary winding and a second terminal operably connected to said first end of said capacitor.

12. The integrated ignition system according to claim 10 wherein said coil driver circuit comprises a switch operably connected between said second end of said primary coil and ground.

13. The integrated ignition system according to claim 10 wherein said integrated ignition system further comprises:

a ground pin;

a battery power supply pin operably connected to said first end of said primary coil; and

an output pin operably connected to said output of said first amplifier.

14. A method of detecting an ionization signal and a driver current feedback signal, comprising the step of multiplexing a charge command signal, the ionization signal and the driver current feedback signal, wherein said step of multiplexing a charge command signal, the ionization signal and the driver current feedback signal comprises the steps of:

outputting an ionization signal;

enabling a charge command signal, whereby a primary winding of an ignition coil is charged;

generating a gating voltage by flowing charge gate current across a first resistor;

generating a second voltage by outputting an ionization signal across said first resistor and a second resistor;

comparing said gating voltage and said second voltage;

outputting a charge command signal if said gating voltage is greater than said second voltage;

outputting a charge current feedback signal while said charge command is enabled;

disabling said charge command signal; and

outputting said ionization signal after said charge command signal is disabled.

15. The method according to claim 14 wherein said step of outputting a charge current feedback signal while said charge command signal is enabled comprises switching between said ionization signal and said charge current feedback signal when said charge command signal is enabled.

16. The method according to claim 14 wherein said step of outputting said ionization signal after said charge command signal is disabled comprises switching between said charge current feedback signal and said ionization signal when said charge command signal is disabled.

17. The method according to claim 14 wherein said ionization signal and said charge current feedback signal are output on a same output pin.