Ignition system and method for checking electrodes of a spark plug of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10156221-B2
Application number	US-201515514016-A
Country	US
Kind code	B2
Filing date	Aug 3, 2015
Priority date	Sep 29, 2014
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

A method for checking electrodes of a spark gap of an ignition system for a combustion chamber of an internal combustion engine with an externally provided ignition includes generating a spark at the spark gap in an operating state without ignition of an ignitable mixture in the combustion chamber; ascertaining a parameter or characteristic function representing the spark current, the spark voltage, and/or the spark duration; comparing the parameter or the characteristic function to a reference; adapting an energy for a voltage buildup for a further spark generation for the mixture ignition and/or for maintaining an ignition spark for the mixture ignition, in particular for a future ignition process, as a function of a difference between the parameter or the characteristic function and the reference.

First claim

What is claimed is:

1. A method for operating an ignition system for generating a spark at a spark gap in a combustion chamber of an internal combustion engine with an externally supplied ignition, the method comprising:
generating the spark at the spark gap in an operating state without ignition of an ignitable mixture in the combustion chamber;
ascertaining, by an evaluation unit, a parameter or characteristic function representing at least one of the spark current, the spark voltage, and the spark duration;
comparing, by the evaluation unit, the parameter or the characteristic function to a reference;
adapting, by the evaluation unit, at least one of an amount and a duration of voltage at the spark gap for at least one of generating and maintaining a further ignition spark for ignition of the mixture as a function of a difference between the parameter or the characteristic function and the reference, determined as a result of the comparison; and
generating and maintaining the further ignition spark at the spark gap for the ignition of the mixture, using the adapted voltage;
wherein the generation of the further ignition spark is performed with a primary voltage generator, and
wherein the further ignition spark is maintained using a step-up chopper.

2. The method of claim 1 , wherein the reference is a first threshold value which is specified on the basis of the spark gap at an initial operation of the ignition system and while taking a maximally permitted wear into account.

3. The method of claim 1 , wherein the voltage is adapted by increasing a voltage availability through the primary voltage generator or through the step-up chopper.

4. The method of claim 3 , wherein:
the reference is a first threshold value which is specified on the basis of the spark gap at an initial operation of the ignition system and while taking a maximally permitted wear into account; and
the voltage availability at electrodes that are at the spark gap is increased in a step-by-step manner until a predefined second threshold value has been reached.

5. The method of claim 4 , wherein, after the predefined second threshold value has been exceeded, a fault signal is output which indicates that an exchange of the electrodes is required.

6. The method of claim 1 , wherein the comparing includes evaluating a profile of the characteristic function over the time.

7. The method of claim 1 , wherein the spark that is generated at the spark gap in the operating state without the ignition is generated at an instant without a presence of an ignitable mixture.

8. The method of claim 1 , wherein the spark that is generated at the spark gap in the operating state without the ignition is generated at an instant that is without a presence of an ignitable mixture and that features low turbulence in the combustion chamber.

9. The method of claim 1 , wherein the spark that is generated at the spark gap in the operating state without the ignition is generated in an exhaust working stroke of the internal combustion engine.

10. The method of claim 1 , wherein the spark that is generated at the spark gap in the operating state without the ignition is generated in an exhaust working stroke with closed intake valves of the internal combustion engine.

11. The method of claim 1 , wherein the further ignition spark is maintained using a constant electrical power of a step-up chopper.

12. The method of claim 1 , wherein the parameter is ascertained in an essentially stationary state.

13. The method of claim 1 , wherein an electrical voltage is used as reference, the method further comprising:
ascertaining whether an overshooting condition is satisfied by determining whether the spark voltage exceeds the reference; and
at least one of increasing a voltage availability for spark generation and increasing an output power of a primary voltage generator or a step-up chopper if the overshooting condition is satisfied.

14. The method of claim 13 , wherein the increasing of the output power of the step-up chopper is performed, the increasing being by increasing at least one of a spark current and an output current of the step-up chopper.

15. The method of claim 1 , wherein an electrical current is used as reference, the method further comprising:
ascertaining whether an undershooting condition is satisfied by determining whether the spark current or an output current of a step-up chopper undershoots the reference; and
at least one of increasing a voltage availability for spark generation and increasing an output power of a primary voltage generator or a step-up chopper if the undershooting condition is satisfied.

16. The method of claim 15 , wherein the increasing of the output power of the step-up chopper is performed, the increasing being by increasing at least one of a spark current and an output current of the step-up chopper.

17. The method as recited in claim 1 , wherein the evaluation unit includes one of: (i) a programmable processor, (ii) a programmable controller, (iii) an ASIC, or (iv) a Field Programmable Gate Array.

18. The method as recited in claim 1 , the adapting includes increasing the at least one of the amount and the duration of the voltage at the spark gap using a step-up chopper.

19. An ignition system for an internal combustion engine with externally provided ignition, the ignition system comprising:
a spark gap;
a primary voltage generator; and
an evaluation unit, wherein the evaluation unit is configured to:
use the primary voltage generator to generate a spark at the spark gap in an operating state without ignition of an ignitable mixture in the combustion chamber;
ascertain a parameter or characteristic function representing at least one of the spark current, the spark voltage, and the spark duration;
compare the parameter or the characteristic function to a reference;
adapt at least one of an amount and a duration of voltage at the spark gap for at least one of generating and maintaining a further ignition spark for ignition of the mixture as a function of a difference between the parameter or the characteristic function and the reference, determined as a result of the comparison; and
generate and maintain the further ignition spark at the spark gap for the ignition of the mixture, using the adapted voltage;
wherein the generation of the further ignition spark is performed with a primary voltage generator, and
wherein the further ignition spark is maintained using a step-up chopper.

20. The ignition system of claim 19 , furthermore comprising:
a step-up chopper whose output lies in an electrical loop with the spark gap and that is configured to inject a predefined electrical quantity in order to maintain the further ignition spark.

21. The ignition system of claim 20 , wherein the predefined electrical quantity is at least one of an output current, an output voltage, and an output power into the spark gap.

22. The ignition system of claim 19 , wherein the evaluation unit is configured to adapt an operating mode of the step-up chopper or a primary voltage generator in response to the result of the comparison.

23. The ignition system as recited in claim 19 , wherein the evaluation unit includes one of: (i) a programmable processor, (ii) a programmable controller, (iii) an ASIC, or (iv) a Field Programmable Gate Array.

24. The ignition system as recited in claim 19 , wherein the primary voltage generator provides at least one of an increase

Assignees

• Bosch Gmbh Robert

Inventors

• Skowronek Tim
• Pawlak Thomas
• Sinz Wolfgang

Classifications

• F02P2017/121

  by measuring spark voltage · CPC title

• F02P9/007

  by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition · CPC title

• H01T15/00

  Circuits specially adapted for spark gaps, e.g. ignition circuits (ignition circuits for internal-combustion engines F02P; electric spark ignition for combustion apparatus F23Q; protection circuits using spark gaps H02H9/06) · CPC title

• F02P15/10

  having continuous electric sparks · CPC title

• F02D41/009

  using means for generating position or synchronisation signals · CPC title