Ignition control system with circulating-current control

Patent metadata

Field	Value
Publication number	US-10975827-B2
Application number	US-201916250407-A
Country	US
Kind code	B2
Filing date	Jan 17, 2019
Priority date	Sep 26, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

In an implementation, a method of operating an ignition circuit can include enabling a charge path control circuit and a switch circuit to charge a primary winding of an ignition coil of the ignition circuit until a threshold current is reached in the primary winding. After reaching the threshold current in the primary winding, the method can include maintaining a current in the primary winding of the ignition coil in correspondence with a current limit by alternatively activating and deactivating the charge path control circuit complementary to alternative activation and deactivation of a circulating-current path control circuit. During the maintaining the current in the primary winding, the method can include initiating a spark in a spark plug included in the ignition circuit, the initiating the spark including controlling an amount of energy delivered from the primary winding to a secondary winding of the ignition coil.

First claim

What is claimed is:

1. A circuit, comprising:
a switch circuit configured to be electrically connected to a first terminal of a primary winding of an ignition coil included in an ignition circuit;
a charge path control circuit electrically coupled between the switch circuit and a ground terminal, such that the primary winding, the switch circuit and the charge path control circuit are electrically coupled in series;
a circulating-current path control circuit electrically connected between the switch circuit and a battery terminal, the battery terminal being configured to be electrically connected to a second terminal of the primary winding of the ignition coil; and
a control circuit configured to operate the switch circuit, the charge path control circuit and the circulating-current path control circuit to:
provide a current to charge the primary winding of the ignition coil until a threshold current is reached in the primary winding by enabling the charge path control circuit and the switch circuit;
after reaching the threshold current in the primary winding, maintaining, until a spark is initiated in a spark plug included in the ignition circuit, a current in the primary winding of the ignition coil in correspondence with a current limit by alternately deactivating the circulating-current path control circuit; and
initiating the spark in the spark plug included in the ignition circuit, the initiating the spark including controlling an amount of energy delivered from the primary winding to a secondary winding of the ignition coil.

2. The circuit of claim 1 , wherein:
the circulating-current path control circuit, when the circulating-current path control circuit is activated and the charge path control circuit is deactivated, defines a looped path including the switch circuit, the battery terminal, and terminals configured to be electrically connected with the ignition coil; and
the charge path control circuit, when the charge path control circuit is activated and the circulating-current path control circuit is deactivated, defines a grounded path including the battery terminal, the switch circuit, the ground terminal, and terminals configured to be electrically connected with the ignition coil.

3. The circuit of claim 1 , wherein the current limit is equal to the threshold current.

4. The circuit of claim 1 , wherein maintaining the current in the primary winding of the ignition coil in correspondence with the current limit includes dithering the current in the primary winding around the current limit.

5. The circuit of claim 1 , wherein the current limit is a first current limit, the control circuit being further configured to operate the switch circuit, the charge path control circuit and the circulating-current path control circuit to maintain the current in the primary winding of the ignition coil between the first current limit and a second current limit, the second current limit being less than the first current limit.

6. The circuit of claim 1 , wherein controlling an amount of energy delivered to the secondary winding of the ignition coil includes controlling a deactivation time of at least one of the switch circuit or the charge path control circuit.

7. The circuit of claim 1 , wherein maintaining the current in the primary winding of the ignition coil in correspondence with the current limit includes operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair.

8. The circuit of claim 7 , wherein operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair includes operating the circulating-current path control circuit and the charge path control circuit using a variable frequency signal.

9. The circuit of claim 8 , wherein the control circuit is further configured to determine a frequency of the variable frequency signal based on a current sensed in the primary winding.

10. The circuit of claim 7 , wherein operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair includes operating the circulating-current path control circuit and the charge path control circuit using a fixed frequency signal with a variable duty cycle.

11. The circuit of claim 10 , wherein the control circuit is further configured to determine a duty cycle of the fixed frequency signal based on a current sensed in the primary winding.

12. A circuit, comprising:
a switch circuit configured to be electrically connected to a first terminal of a primary winding of an ignition coil included in an ignition circuit;
a ground terminal;
a battery terminal;
a charge path control circuit that is electrically coupled with the battery terminal and configured to be electrically coupled with a second terminal of the primary winding, such that the battery terminal, the charge path control circuit, the primary winding and the switch circuit are electrically coupled in series;
a circulating-current path control circuit that is electrically coupled with the ground terminal and configured to be electrically coupled with the second terminal of the primary winding; and
a control circuit configured to operate the switch circuit, the charge path control circuit and the circulating-current path control circuit to:
provide a current to charge the primary winding of the ignition coil until a threshold current is reached in the primary winding by enabling the charge path control circuit and the switch circuit;
after reaching the threshold current in the primary winding, maintaining, until a spark is initiated in a spark plug included in the ignition circuit, a current in the primary winding of the ignition coil in correspondence with at least one current limit by activating and deactivating the circulating-current path control circuit; and
initiating the spark in the spark plug included in the ignition circuit, the initiating the spark including controlling an amount of energy delivered to a secondary winding of the ignition coil.

13. The circuit of claim 12 , wherein:
the circulating-current path control circuit, when the circulating-current path control circuit is activated and the charge path control circuit is deactivated, defines a looped path including the switch circuit, the ground terminal, and terminals configured to be electrically connected with the ignition coil; and
the charge path control circuit, when the charge path control circuit is activated and the circulating-current path control circuit is deactivated, defines a grounded path including the battery terminal, the switch circuit, the ground terminal, and terminals configured to be electrically connected with the ignition coil.

14. The circuit of claim 12 , wherein maintaining the current in the primary winding of the ignition coil in correspondence with the at least one current limit includes operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair.

15. The circuit of claim 14 , wherein operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair includes operating the circulating-current path control circuit and the charge path control circuit using a variable frequency signal.

16. The circuit of claim 14 , wherein operating the circulating-current path control circuit and the charge path control circuit as a complimentary pair includes operating the circulating-current path control circuit and the charge path control circuit using a fixed frequency signal with a variable duty cycle.

Assignees

• Semiconductor Components Ind Llc

Inventors

• Tang Qingquan
• Honma Hirotada
• Takahashi Hajime
• Henry Mitchell

Classifications

• F02P3/051

  Opening or closing the primary coil circuit with semiconductor devices · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• F02P9/002

  Control of spark intensity, intensifying, lengthening, suppression (by means of current control in the storage devices F02P3/05, F02P3/09, during starting F02P15/12) · CPC title

• H03K17/0828

  in composite switches · CPC title

• F02P3/0552 Primary

  Opening or closing the primary coil circuit with semiconductor devices · CPC title