Spark Plug Shuttle Electrode for Diluted Charge Ignition

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Solution Overview

Problem

Internal combustion engines face inefficiencies and pollution issues due to low thermodynamic efficiency and high nitrogen oxide emissions, particularly when operating with high levels of cooled Exhaust Gas Recirculation (EGR), which complicates ignition and combustion processes.

Innovation Solution

A spark plug with a shuttle electrode that allows for the use of a pilot charge to ignite a main charge, utilizing a prechamber for efficient combustion initiation and development, while avoiding the limitations of traditional prechamber designs by retracting the prechamber when not needed and actively cooling its surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prechamber is used to ignite a diluted charge, then ignition reliability is improved, but device complexity increases and the prechamber cannot be actively cooled

Engineering Contradiction:

Improveignition reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the prechamber movable rather than fixed. The prechamber can be retracted into the spark plug body or extended into the combustion chamber based on operating conditions. This dynamic configuration allows the system to have a fixed prechamber structure when needed for reliable ignition of diluted charges, while avoiding the complexity of permanently integrated cooling systems by only deploying the prechamber when active cooling would be necessary.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If cooled EGR is used to dilute the charge, then thermodynamic efficiency is improved, but ignition difficulty increases due to reduced flammability

Engineering Contradiction:

Improvethermodynamic efficiencyVSAvoidignition ease

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent applies the preliminary action principle by introducing a pilot charge into the prechamber before the main diluted charge ignition. The pilot charge, which is more easily ignitable, is prepared and positioned in advance in the prechamber. When ignition is required, the pilot charge ignites first and then ignites the main diluted charge, thereby solving the ignition difficulty caused by cooled EGR dilution while maintaining the thermodynamic efficiency benefits of the diluted charge.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If a fixed prechamber design is used, then manufacturing is simplified, but the prechamber cannot be actively cooled when needed

Engineering Contradiction:

Improveease of manufactureVSAvoidprechamber temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

4Reliability

If pilot charge is used to ignite main charge, then combustion reliability is improved, but energy consumption increases due to pilot charge compression

Engineering Contradiction:

Improvecombustion reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies the merging principle by combining the pilot charge compression process with the main charge compression process. Both charges are compressed simultaneously in the same cylinder during the same compression stroke, rather than compressing the pilot charge separately in advance. This eliminates the need for a separate pilot charge compressor and reduces overall energy consumption while maintaining combustion reliability through the use of pilot charge.

Inventive Principle:

Principle #5Merging (Combining)

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 design enables rapid and complete combustion of the main charge, minimizing energy costs and avoiding pilot charge dispersion, thus improving engine efficiency and reducing emissions without the need for high electrical voltages or complex nitrogen oxide reduction systems.

Implementation Method 1

under the effect of the pressure of the gases, either towards the lamination cavity when the pressure prevailing therein is lower than the pressure prevailing in the combustion chamber, or towards the combustion chamber when the pressure prevailing in the latter is lower than the pressure prevailing in the lamination cavity

Methodology Applied

Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

said spark plug being designed to optimize the efficiency of said pilot charge to ignite said main charge

Methodology Applied

Scientific EffectElectrical discharge: Electric Spark

Implementation Method 3

rapid and complete combustion of the main charge

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10116122B2Spark plug with shuttle electrode

Publication Date: 2018.10.30 RABHI VIANNEY

AI summary

A spark plug with shuttle electrode is provided for an internal combustion engine which includes a combustion chamber in which a main charge diluted with a neutral gas is ignited, the spark plug housing a lamination cavity in which a central electrode opens and in which a lamination injector is able to inject under pressure a pilot charge consisting of an easily flammable combustive-AF fuel mixture, the cavity being connected to the combustion chamber by a lamination duct, while a shuttle electrode is interposed between the central electrode and a ground electrode and can translate in the lamination duct.