SPARK PLUG CONDITION MONITORING

• US 20180100479A1
• Filed: 09/26/2017
• Published: 04/12/2018
• Est. Priority Date: 10/07/2016
• Status: Active Grant

• Current Assignee: Caterpillar Energy Solutions, GmbH (Caterpillar Incorporated)
• Original Assignee: Caterpillar Energy Solutions, GmbH (Caterpillar Incorporated)
• Inventors: Shah, Darshit, Lenhardt, Heiko
• Granted Patent: US 10,590,903 B2
• Time in Patent Office: Days
• CPC Class Codes: F02B 19/12 with positive ignition engines with non-timed positive ignition, and with incandescent chambers F02B9/08
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02P 17/12 Testing characteristics of the spark, ignition voltage or current testing of sparking plugs H01T13/60
• CPC Class Codes: F02P 2017/121 by measuring spark voltage
• CPC Class Codes: F02P 2017/123 Generating additional sparks for diagnostics
• CPC Class Codes: F02P 5/152 dependent on pinking detecting or indicating knocks in internal-combustion engines G01L23/22
• CPC Class Codes: G01M 15/11 by detecting misfire
• CPC Class Codes: H01T 13/60 of electrical properties
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

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.

Claims

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 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.

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 depending on a specific combination of the at least one determined engine operation condition and the determined operation value associated with the electrical parameter of the spark plug.

3. The method of claim 1, wherein the 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, further comprising:

performing a preset spark plug test procedure for testing operation of the spark plug.

5. The method of claim 4, 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.

6. The method of claim 4, 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,

if misfire occurs, determining that the spark plug has a reduced sparkability.

7. The method of claim 4, 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,

if misfire occurs, determining that a fuel air mixture has a reduced ignitability.

8. The method of claim 4, further comprising:

adapting an operation of the internal combustion engine if the preset spark plug test procedure indicates that a fuel air mixture has a reduced ignitability and/or the preset a spark plug test procedure indicates that the spark plug has a reduced sparkability.

9. The method of claim 4, 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 spark plug test procedure is performed if a comparison between the reference value and the operation value indicates an abnormal behavior of the spark plug.

10. The method of claim 9, 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.

11. The method of claim 9, wherein

the reference value is a first voltage amount of a secondary breakdown voltage of an ignition coil associated with the spark plug;

and

the operation value is a second voltage amount of a secondary breakdown voltage of the ignition coil associated with the spark plug;

the abnormal behavior of the spark plug includes a determination that the operation value is smaller than the reference value.

12. 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.

13. 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.

14. An ignition system for an internal combustion engine, 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 spark plug;

determine at least one parameter indicative of a current engine operation condition of the internal combustion engine; and

determine 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, wherein the operation value is an actual risetime duration (CR) of a primary current of the ignition coil of the ignition system.

15. 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 the ignition system during actuation of the spark plug;

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.