Digital ignition

• US 6,196,208 B1
• Filed: 10/30/1998
• Issued: 03/06/2001
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: ACCEL Performance Group, LLC (High Performance Industries, Inc.), Racepak LLC (High Performance Industries, Inc.), MSD, LLC, Powerteq LLC, Racing Services, Inc.
• Original Assignee: Autotronic Controls Corporation (Valueact Holdings II LP)
• Inventors: Masters, Stephen C.
• Primary Examiner(s): Kwon, John
• Application Number:
  US09/182,984
• Time in Patent Office: 858 Days
• Field of Search: 123/597, 123/598, 123/644
• US Class Current: 123/597
• CPC Class Codes: F02D 31/008 for idle speed control

Abstract

An electronic ignition system includes a converter for receiving DC power from a source of DC power such as a battery. The convertor converts the DC power at low voltage to a high frequency signal which is stepped up to provide a higher voltage to a charge storage device such as a capacitor. The higher voltage on the capacitor is then made available to an ignition coil under the control of a microprocessor or a microcontroller for providing high voltage electrical energy to one or more spark plugs of an internal combustion engine.

Claims

1. An ignition control system for use with an engine ignition coil for receiving voltage within a predetermined operating range, comprising:

an electrical input for receiving a direct current voltage from a power source;

a convertor connected to the electrical input for converting the direct current voltage to a predetermined converted high voltage by first converting the direct current voltage to a high frequency voltage and deriving a high voltage fron the high frequency voltage before applying the predetermined converted high voltage to the ignition coil; and

a controller for regulating current available from the convertor to be within the predetermined operating range to allow the convertor to supply proper high voltage to the ignition coil.

2. An ignition control system according to claim 1, wherein the controller comprises an output for providing a reference voltage that tracks the power source direct current voltage for regulating current supply to the convertor.

3. An ignition control system according to claim 1, further comprising a current feedback circuit for determining whether the convertor is operating within a predetermined current range.

4. An ignition control system according to claim 1, further comprising a current limiting circuit for limiting current output from the convertor to reduce current runaway conditions at the controller.

5. An ignition control system according to claim 1, further comprising a temperature control circuit for allowing the convertor to provide the ignition coil a predetermined voltage when the convertor is operating over a range of temperatures.

6. An ignition control system for use with an engine ignition coil for receiving voltage within a predetermined operating range, comprising:

an electrical input for receiving a voltage from a power source;

a convertor connected to the electrical input for converting the voltage to a predetermined converted voltage before applying the predetermined converted voltage to the ignition coil;

a controller for regulating current available from the convertor to be within the predetermined operating range to allow the convertor to supply proper voltage to the ignition coil, the controller having an output for controlling the convertor, the output having different modes based upon operating conditions of the ignition system; and

input circuitry for inputting the operating conditions of the ignition system to the controller.

7. An ignition system according to claim 6 further comprising a charge storage circuit for receiving and storing the converted energy from the convertor for application to the ignition coil, and

a feedback circuit of the input circuitry for monitoring the charge level of the charge storage circuit supplied by the convertor.

8. An ignition control system according to claim 7 wherein the charge storage circuit includes a reverse current flow path to allow the charge storage circuit to store a predetermined amount of charge when the ignition coil is disconnected from the ignition to ensure proper operation of the convertor.

9. An ignition control system according to claim 7 wherein the output comprises a signal causing the charge storage circuit to stop charging when a reference voltage from the feedback circuit based on the charge level monitored thereby is below a predetermined voltage level to prevent a circuit runaway condition by the charge storage circuit.

10. An ignition control system according to claim 6 wherein the input circuitry comprises a shutdown control circuit for monitoring the power source voltage and the output comprises a signal causing the convertor to shut down to limit overvoltage damage to the ignition control system if the power source voltage exceeds a predetermined threshold voltage.

11. An ignition control system according to claim 10 wherein the shutdown control circuit comprises a clamping circuit for clamping the voltage received by the convertor to a predetermined level to supply a level voltage to the convertor to prevent operation of the convertor at excessively high received input voltages.

12. An ignition control system according to claim 11 wherein the clamping circuit further comprises a current limiting device to limit maximum source current at the convertor to prevent one or more voltage surges to the ignition control system when the clamping device is unclamped and the convertor is operational.

13. A ignition control system according to claim 6 wherein the controller comprises a clamping pin which is clamped at a predetermined voltage level to shut down the convertor and which is unclamped at voltage levels below the predetermined voltage level to allow the convertor to generate the predetermined converted voltage, and

the input circuitry comprises a current limiting circuit connected to the convertor to limit the amount of source current at the clamping pin for allowing the controller to regulate the clamping pin output level to minimize power surges.

14. An ignition control system according to claim 13 wherein the current limiting circuit comprises a current limiting device connected between the controller and ground for allowing the current limiting circuit to maintain a predetermined level of current at the clamping pin to minimize oversupply of current at the clamping pin.

15. An ignition control system according to claim 14 wherein the current limiting device comprises one of a resistor and a current diode to provide a soft clamp at the clamping pin.