Method for controlling a corona ignition system of a cyclically operating internal combustion engine

Patent metadata

Field	Value
Publication number	US-9797365-B2
Application number	US-201514642434-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Mar 13, 2014
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A method for controlling a corona ignition system in which a corona discharge is produced at an ignition electrode by exciting a resonating circuit with an AC voltage produced by a high-frequency generator. The AC voltage is adjusted to a target value depending on an operating state of the engine. Combustion onset is determined by evaluating an electrical variable of the resonating circuit and the target value of the AC voltage is reduced by a predefined value following a predefined number of engine cycles or a predefined operating period. The determined combustion onset is evaluated in one or more engine cycles. The target value for the momentary engine operating state is then increased if, by evaluation of the combustion onset, it is found that a predefined requirement is no longer met. Otherwise, the reduced target value is stored as a new target value for the momentary engine operating state.

First claim

What is claimed is:

1. A method for controlling a corona ignition system of a cyclically operating internal combustion engine, the method comprising:
producing a corona discharge at an ignition electrode by exciting a resonating circuit with an AC voltage produced by a high-frequency generator, said resonating circuit comprising the ignition electrode;
adjusting the AC voltage to a target value that is set as a function of an operating state of the engine;
detecting a combustion onset by evaluating an electrical variable of the resonating circuit; and
evaluating the combustion onset from one or a number of engine cycles, wherein the target value of the AC voltage is increased if, by evaluation of the combustion onset, it is determined that a predefined requirement is no longer met.

2. The method according to claim 1 , wherein:
the target value of the AC voltage is reduced by a predefined value whenever a predefined number of engine cycles or a predefined operating period has passed;
the combustion onset determined with the reduced target value of the AC voltage is evaluated for one or more engine cycles; and
if it is determined from the evaluation of the combustion onset that the predefined requirement is no longer met, the target value of the AC voltage for the engine operating state is increased by more than the predefined value, and, if it is determined by the evaluation of the combustion onset that the predefined requirement is still met, the reduced target value is stored as a new target value for the engine operating state.

3. The method according to claim 1 , wherein the combustion onset is evaluated by being compared with a reference value for the operating state of the engine, wherein the predefined requirement is met when the combustion onset does not exceed the reference value.

4. The method according to claim 1 , wherein the combustion onset is evaluated by comparing a characteristic variable of a scattering of the combustion onset with a reference value, wherein the predefined requirement is met when the combustion onset does not exceed the reference value.

5. The method according to claim 4 , wherein the characteristic variable of the scattering is the variance.

6. The method according to claim 2 , wherein, if, by evaluation of the combustion onset, it is determined that the requirement defined by a reference value is no longer met, the target value of the AC voltage is increased by a value that is dependent on the deviation from the reference value.

7. The method according to claim 1 , wherein the predefined value is fixed as an absolute value.

8. The method according to claim 1 , wherein the target value of the AC voltage is increased at least by twice the predefined value if, by evaluation of the combustion onset in one or more engine cycles, it is determined that the predefined requirement is no longer met.

9. The method according to claim 1 , wherein the predefined value is at most 2% of the target value of the AC voltage.

10. The method according to claim 1 , wherein, by evaluating an electrical variable of the resonating circuit, it is monitored whether an arc discharge occurs and, if so, the target value of the AC voltage is reduced by a value that is greater than the predefined value by which the target value of the AC voltage is reduced following a predefined number of engine cycles or following a predefined operating period.

Assignees

• Borgwarner Ludwigsburg Gmbh

Inventors

• Schenk Alexander
• Schremmer Torsten
• Rixecker Georg

Classifications

• F02B77/085

  with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame · CPC title

• F02P17/12

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

• F02P2017/121

  by measuring spark voltage · CPC title

• F02D35/028

  by determining the combustion timing or phasing · 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