Control apparatus of an ignition spark plug and engine electronic ignition system having open secondary protection

Patent metadata

Field	Value
Publication number	US-9470202-B2
Application number	US-201314097852-A
Country	US
Kind code	B2
Filing date	Dec 5, 2013
Priority date	Jan 3, 2013
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A control apparatus of an engine ignition spark plug includes a switch having a control terminal and an output terminal connected to an external transformer. The switch assumes a closed state for supplying energy to the transformer, and an open state for the transformer to supply energy to the spark plug. A measuring module measures a time duration where, in the open state, a voltage at the output terminal of the switch decreases from a first value to a second value. A detecting module detects an operating condition of the spark plug based on comparing the measured time duration to a time threshold, and to generate a detecting signal based on the comparing.

First claim

The invention claimed is:

1. A control apparatus for an engine ignition spark plug comprising:
a switch comprising a control terminal and an output terminal both to be connected to an external transformer, said switch having a closed state to supply a voltage to the transformer and an open state to release the voltage from the transformer to the spark plug;
a measuring module configured to measure in the open state a time duration of a voltage at the output terminal decreasing from a first value to a second value;
a detecting module configured to detect an operating condition of the spark plug based on comparing the measured time duration to a time threshold, and to generate a detecting signal based on the comparing; and
a driving module connected to the control terminal and configured to generate a driving signal for said switch based on the detecting signal;
said detecting module configured to detect a first anomaly condition corresponding to a failed electrical spark of the spark plug, and a second anomaly condition corresponding to more than one failed electrical spark of the spark plug, with the driving signal to modify an operating mode of said switch based on detecting the first and second anomaly conditions.

2. The control apparatus according to claim 1 , wherein said measuring module comprises:
a measuring sensor connected to said output terminal and configured to generate a reading voltage; and
a comparing module configured to compare a supply voltage coupled to the external transformer with the reading voltage, and to generate a first comparing signal based on the comparing.

3. The control apparatus according to claim 2 , wherein said measuring module further comprises a time detecting module configured to generate a time duration value corresponding to a time duration of the first comparing signal.

4. The control apparatus according to claim 3 , wherein said detecting module comprises a time comparing module configured to compare the time duration value with the time threshold, and to generate a second comparing signal having
a first value representative of a failed spark of the spark plug if the time duration value is less than the time threshold; and
a second value representative of a successful spark of the spark plug if the time duration value is greater than the time threshold.

5. The control apparatus according to claim 4 , wherein said detecting module further comprises a register configured to increment a count value therein when the second comparing signal takes a value that is one or more times the first value, and provides the detecting signal based on the count value.

6. The control apparatus according to claim 5 , wherein said driving module comprises:
a reference voltage generator configured to receive the detecting signal and generate a corresponding electrical reference voltage; and
an electrical current limiting circuit configured to generate the driving signal as a function of the reference electrical voltage, and to adjust an electrical current at the output terminal of said switch.

7. The control apparatus according to claim 6 , wherein said detecting module and said reference voltage generator are configured so that the reference electrical voltage decreases when the detecting signal indicates an increment of the count value.

8. The control apparatus according to claim 7 , wherein said detecting module is configured so that the reference electrical voltage takes a value between a minimum voltage value that is greater than a minimum voltage necessary for generating a spark in the spark plug, and a maximum voltage value corresponding to a predetermined electrical current at the collector terminal.

9. The control apparatus according to claim 7 , further comprising an electrical voltage sensing device comprising:
at least one first terminal connected to an additional output terminal of said switch for receiving a voltage;
a second terminal for providing to the current limiting circuit a detected voltage indicating the voltage being drawn; and
said current limiting circuit being configured to compare the reference voltage with the detected voltage, and to generate the corresponding driving signal for the switch.

10. The control apparatus according to claim 1 , wherein said switch comprises at least one of a Darlington transistor, a three-stage transistor, and an IGBT transistor.

11. An electronic ignition system for an internal combustion engine comprising:
a spark plug;
a transformer having a primary winding, and a secondary winding connected to said spark plug; and
a control apparatus connected to the primary winding and comprising
a switch comprising a control terminal and an output terminal both connected to the primary winding of said a transformer, said switch having a closed state to supply a voltage to said transformer and an open state to release the voltage from said transformer to said spark plug,
a measuring module configured to measure in the open state a time duration of a voltage at the output terminal decreasing from a first value to a second value,
a detecting module configured to detect an operating condition of said spark plug based on comparing the measured time duration to a time threshold, and to generate a detecting signal based on the comparing, and
a driving module connected to the control terminal and configured to generate a driving signal for said switch based on the detecting signal,
said detecting module configured to detect a first anomaly condition corresponding to a failed electrical spark of said spark plug, and a second anomaly condition corresponding to more than one failed electrical spark of said spark plug, with the driving signal to modify an operating mode of said switch based on detecting the first and second anomaly conditions.

12. The electronic ignition system according to claim 11 , further comprising a control module coupled to said control apparatus to control ignition timing of said spark plug.

13. The electronic ignition system according to claim 11 , wherein said measuring module comprises:
a measuring sensor connected to said output terminal and configured to generate a reading voltage;
a comparing module configured to compare a supply voltage coupled to the external transformer with the reading voltage, and to generate a first comparing signal based on the comparing; and
a time detecting module configured to generate a time duration value corresponding to a time duration of the first comparing signal.

14. The electronic ignition system according to claim 13 , wherein said detecting module comprises:
a time comparing module configured to compare the time duration value with the time threshold, and to generate a second comparing signal having a first value representative of a failed spark of said spark plug if the time duration value is less than the time threshold, and a second value representative of a successful spark of said spark plug if the time duration value is greater than the time threshold; and
a register configured to increment a count value therein when the second comparing signal takes a value that is one or more times the first value, and provides the detecting signal based on the count value.

15. The electronic ignition system according to claim 14 , wherein said driving module comprises:
a reference voltage generator configured to receive the detecting signal and generate a corresponding electrical reference voltage; and
an electrical current limiting circuit configured to generate the driving signal as a function of the reference electrical voltage, and to adjust an electrical current at

Assignees

• St Microelectronics Srl

Inventors

• Torrisi Giovanniluca
• Trecarichi Calogeroandrea

Classifications

• F02P9/00 Primary

  Electric spark ignition control, not otherwise provided for · CPC title

• F02P3/0552

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

• F02P3/051 Primary

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

• F02P2017/121

  by measuring spark voltage · CPC title

• F02P17/12

  Testing characteristics of the spark, ignition voltage or current (testing of sparking plugs H01T13/60) · CPC title