Multipoint Ignition Electrode Heat Value Optimization

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Solution Overview

Problem

In multipoint ignition devices, all electrode pairs are initially set with identical heat values, leading to temperature imbalances, causing some to fall below the self-cleaning temperature, resulting in pollution, while others exceed the pre-ignition temperature, resulting in pre-ignition.

Innovation Solution

Individual heat values are set for each electrode pair based on their position around the combustion chamber, with higher values on the exhaust side and lower values for those directly exposed to fresh air, to maintain temperatures within the appropriate range of 450°C to 850°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If all electrode pairs are set with identical heat values, then manufacturing is simplified, but temperature uniformity deteriorates causing some electrode pairs to fall below self-cleaning temperature (pollution) and others to exceed pre-ignition temperature

Engineering Contradiction:

Improveheat value settingVSAvoidtemperature uniformity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by setting different heat values for electrode pairs based on their specific positions within the combustion chamber. Electrode pairs are categorized into multiple groups (first through fourth groups) with progressively different heat values, allowing each group to be optimized for its local thermal environment and prevent both pollution and pre-ignition

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the electrode pairs into distinct groups based on their positions and thermal characteristics. By dividing the electrode pairs into multiple categories with different heat value settings, the system can address the temperature uniformity problem while maintaining manageable manufacturing complexity

Inventive Principle:

Principle #1Segmentation

2Reliability

If electrode pair temperature is increased to prevent pollution, then self-cleaning is improved, but pre-ignition occurs

Engineering Contradiction:

Improveself-cleaning functionVSAvoidpre-ignition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent resolves this contradiction by applying local quality - different electrode pairs are assigned different heat values based on their specific positions. This allows each electrode pair to maintain its temperature within the optimal range for both self-cleaning and preventing pre-ignition, rather than using a uniform temperature setting for all electrode pairs

Inventive Principle:

Principle #3Local quality

3Reliability

If electrode pair temperature is decreased to prevent pre-ignition, then pre-ignition is avoided, but pollution occurs due to insufficient self-cleaning

Engineering Contradiction:

Improvepre-ignition preventionVSAvoidelectrode pair pollution

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

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 ensures that all electrode pairs operate within the optimal temperature range, preventing pollution and pre-ignition, thereby enhancing the reliability and efficiency of the ignition process.

Implementation Method 1

a plurality of electrode pairs constituting ignition gaps are disposed around a cylinder opening portion such that an air-fuel mixture in a combustion chamber is ignited from the plurality of ignition gaps

Methodology Applied

Scientific EffectElectrical discharge: Electric Spark

Implementation Method 2

the temperature of each electrode pair in this multipoint ignition device must be maintained within an appropriate range (between 450° C. and 1000° C.)

Methodology Applied

Scientific EffectThermal balance:

Implementation Method 3

When the temperature of the electrode pair is lower than a self-cleaning temperature (between 450° C. and 500° C.), carbon sticks to the electrode pair

Methodology Applied

Scientific EffectSelf-cleaning:

Data Source

PatentUS7441539B1Multipoint ignition device

Publication Date: 2008.10.28 MIYAMA

AI summary

Respective heat values of a plurality of electrode pairs P1 to P8 are set individually such that the temperatures of all of the plurality of electrode pairs (P1 to P8) are kept within an appropriate temperature range in which a temperature no lower than a self-cleaning temperature is set as a lower limit temperature and a lower temperature than a pre-ignition temperature is set as an upper limit temperature.