Spark plug condition monitoring

Patent metadata

Field	Value
Publication number	US-10590903-B2
Application number	US-201715715428-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Oct 7, 2016
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

A method for monitoring an ignition system including a spark plug of an internal combustion engine is disclosed. The method comprises determining an operation value associated with an electrical parameter indicative of an operation of the ignition system during actuation of the spark plug. The method further comprises determining at least one parameter indicative of a current engine operation condition of the internal combustion engine, and determining a current spark plug state of the spark plug based on the at least one engine parameter and the operation value associated with the electrical parameter of the ignition system.

First claim

What is claimed is:

1. A method for monitoring an ignition system including a spark plug of an internal combustion engine, the method comprising:
determining an operation value associated with an electrical parameter indicative of an operation of the ignition system during actuation of the spark plug;
determining at least one engine parameter indicative of a current engine operation condition of the internal combustion engine;
determining a current spark plug state of the spark plug based on the at least one engine parameter and the operation value associated with the electrical parameter of the ignition system; and
performing a preset spark plug test procedure for testing operation of the spark plug.

2. The method of claim 1 , wherein the step of determining the current spark plug state uses a map providing a plurality of empirically determined spark plug states, each spark plug state of the plurality of empirically determined spark plug states depending on a specific combination of the at least one determined engine parameter and the determined operation value associated with the electrical parameter of the spark plug.

3. The method of claim 1 , wherein the determined operation value is an actual risetime duration of a primary current of an ignition coil of the ignition system.

4. The method of claim 1 , wherein the preset spark plug test procedure is performed when misfire occurs and/or the determined operation value associated with the electrical parameter indicative of the operation of the ignition system indicates an abnormal behavior of the spark plug.

5. The method of claim 1 , wherein the preset spark plug test procedure comprises a sparkability test including:
determining that misfire and/or an abnormal behavior of the spark plug occurs for a first ignition timing of the spark plug;
actuating the spark plug at a preset sparkability test ignition timing before the first ignition timing; and
when misfire occurs, determining that the spark plug has a reduced sparkability.

6. The method of claim 1 , wherein the preset spark plug test procedure comprises an ignitability test including:
determining that misfire and/or an abnormal behavior of the spark plug occurs for a first ignition timing of the spark plug;
actuating the spark plug at a preset ignitability test ignition timing after the first ignition timing; and
when misfire occurs, determining that a fuel air mixture has a reduced ignitability.

7. The method of claim 1 , further comprising adapting an operation of the internal combustion engine when the preset spark plug test procedure indicates that a fuel air mixture has a reduced ignitability and/or the preset spark plug test procedure indicates that the spark plug has a reduced sparkability.

8. The method of claim 1 , further comprising determining a reference value associated with the electrical parameter indicative of an operation of the ignition system during actuation of the spark plug,
wherein the reference value is determined during an operation of the internal combustion engine with compression and without combustion, and
wherein the preset spark plug test procedure is performed when a comparison between the reference value and the operation value indicates an abnormal behavior of the spark plug.

9. The method of claim 8 , wherein
the reference value is a first risetime duration of a primary current of an ignition coil of the ignition system;
the operation value is a second risetime duration of a primary current of the ignition coil; and
the abnormal behavior of the spark plug includes a determination that the operation value is smaller than the reference value.

10. The method of claim 8 , wherein
the reference value is a first voltage amount of a secondary breakdown voltage of an ignition coil associated with the spark plug;
the operation value is a second voltage amount of a secondary breakdown voltage of the ignition coil associated with the spark plug; and
the abnormal behavior of the spark plug includes a determination that the operation value is smaller than the reference value.

11. The method of claim 1 , wherein:
the step of determining the operation value includes determining a plurality of operation values and averaging the plurality of operation values; and/or
the operation value is determined during an operation of the internal combustion engine including compression and combustion.

12. The method of claim 1 , further comprising:
determining that misfire occurs based on measurements of in-cylinder temperature, in-cylinder pressure, engine speed changes, ion sensing, and/or a detonation sensor.

13. An ignition system for an internal combustion engine, the ignition system comprising:
at least one spark plug;
an ignition coil for the at least one spark plug; and
a control unit electronically connected to the ignition coil and configured to:
determine an operation value associated with an electrical parameter indicative of an operation of the ignition system during actuation of the at least one spark plug;
determine at least one engine parameter indicative of a current engine operation condition of the internal combustion engine; and
determine a current spark plug state of the at least one spark plug based on the at least one engine parameter and the operation value associated with the electrical parameter of the ignition system, wherein the operation value is an actual risetime duration (CR) of a primary current of the ignition coil of the ignition system.

14. A computer program comprising computer-executable instructions which, when run on a computer, cause the computer to perform the steps of:
determining an operation value associated with an electrical parameter indicative of an operation of an ignition system of an internal combustion engine during actuation of a spark plug of the internal combustion engine;
determining at least one engine parameter indicative of a current engine operation condition of the internal combustion engine;
determining a current spark plug state of the spark plug based on the at least one engine parameter and the operation value associated with the electrical parameter of the ignition system; and
performing a preset spark plug test procedure for testing operation of the spark plug.

15. The ignition system of claim 13 , wherein the control unit is further configured to perform a preset spark plug test procedure for testing operation of the at least one spark plug.

16. The ignition system of claim 15 , wherein the preset spark plug test procedure is performed when misfire occurs and/or the operation value associated with the electrical parameter indicative of the operation of the ignition system indicates an abnormal behavior of the spark plug.

17. The ignition system of claim 15 , wherein the preset spark plug test procedure comprises a sparkability test including:
determining that misfire and/or an abnormal behavior of the spark plug occurs for a first ignition timing of the spark plug;
actuating the spark plug at a preset sparkability test ignition timing before the first ignition timing; and
when misfire occurs, determining that the spark plug has a reduced sparkability.

18. The ignition system of claim 15 , wherein the preset spark plug test procedure comprises an ignitability test including:
determining that misfire and/or an abnormal behavior of the spark plug occurs for a first ignition timing of the spark plug;
actuating the spark plug at a preset ignitability test ignition timing after the first ignition timing; and
when misfire occurs,

Assignees

• Caterpillar Energy Solutions Gmbh

Inventors

• Shah Darshit
• Lenhardt Heiko

Classifications

• F02P5/152

  dependent on pinking (detecting or indicating knocks in internal-combustion engines G01L23/22) · CPC title

• F02P2017/121

  by measuring spark voltage · CPC title

• F02P17/10

  Measuring dwell or antidwell time · CPC title

• F02P17/12 Primary

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

• F02P17/00 Primary

  Testing of ignition installations, e.g. in combination with adjusting (testing fuel injection apparatus F02M65/00; testing ignition installations in general F23Q23/00); Testing of ignition timing in compression-ignition engines · CPC title