Spark Plug Electrode Wear Tracking Using Ignition Risetime

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The wear of spark plug electrodes in internal combustion engines, caused by high temperatures, leads to increased ignition energy requirements and potential misfires, necessitating timely monitoring to ensure optimal engine performance and prevent sub-optimal operation.

Innovation Solution

A method and system for determining the wear rate of spark plug electrodes by calculating a risetime number and operating condition indicator, which are used to generate a spark plug state indicator, allowing for the calculation of wear rate based on differences in state indicators stored at predetermined intervals, with the results used to predict the lifespan and determine when replacement is necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spark plug electrodes operate at high temperatures to initiate combustion, then combustion initiation capability is improved, but electrode erosion increases leading to increased wear

Engineering Contradiction:
Improvecombustion initiation capabilityVSAvoidelectrode wear
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback mechanism by continuously monitoring the risetime of ignition voltage and comparing it against reference values to detect electrode wear. The control unit calculates wear indicators based on risetime measurements and stores them for trend analysis, enabling real-time feedback on electrode condition without affecting the high-temperature operation needed for combustion initiation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces direct physical measurement of electrode wear (mechanical inspection or disassembly) with electrical measurement of ignition voltage risetime. By substituting mechanical wear detection with electrical parameter monitoring, the system can continuously assess electrode condition without mechanical intervention, maintaining both combustion performance and wear detection capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If electrode wear is monitored frequently to detect wear early, then wear detection accuracy is improved, but system complexity and measurement requirements increase

Engineering Contradiction:
Improvewear detection accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the wear detection function from complex multi-parameter monitoring systems and focuses solely on measuring the risetime of ignition voltage. By taking out only the essential measurement parameter (risetime) and comparing it against stored reference values, the system achieves accurate wear detection with minimal complexity, avoiding the need for multiple sensors or complex analysis systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the measurement parameter from direct physical electrode dimension or material composition to electrical risetime parameter. This parameter transformation simplifies the measurement system while maintaining detection accuracy, as risetime can be measured using standard electrical equipment already present in the ignition system, converting a complex mechanical wear measurement into a simple electrical timing measurement.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables real-time monitoring of spark plug wear, allowing for timely replacement and maintaining optimal engine performance by predicting the lifespan of the spark plug and preventing misfires due to excessive wear.

Implementation Method 1

an ignition coil (54) for the at least one spark plug (30)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

high electrode temperatures and, as a consequence, to an erosion of the electrodes

Methodology Applied
Scientific EffectThermal erosion: Erosion

Data Source

PatentEP3578804B1Spark plug electrode wear rate determination for a spark-ignited engine
Publication Date: 2024.07.24 CATERPILLAR ENERGY SOLUTIONS
  • EP3578804B1 patent drawingFigure 1
  • EP3578804B1 patent drawingFigure 2
  • EP3578804B1 patent drawingFigure 3

AI summary

A method for determining the wear rate of a spark plug electrode of an ignition system of an internal combustion engine comprises determining (100) a risetime number indicating the time required for raising the current and thereby the primary energy which is supplied to an ignition coil (54) of the spark plug (30) from an inactive level to a predetermined level, determining (200) an operating condition indicator configured to indicate an operating condition of the ignition system, determining (300) a wear rate of the spark plug electrode based on a difference of a first spark plug state indicator at a first time instance and a second spark plug state indicator at a second time instance, wherein the first time instance and the second time instance are separated by a predetermined time interval, wherein the spark plug state indicator is determined as a value based on the risetime number and the operating condition indicator.