Pre-Chamber Spark Plug Cooling via Phase-Change Thermal Conductor

Solution Overview

Problem

Spark ignition engines with pre-chambers face challenges in cooling the spark plug while maintaining thermal efficiency, as conventional materials with low thermal conductivity for insulation do not effectively manage heat dissipation from high-temperature components.

Innovation Solution

A thermal-conductive substance, solid at room temperature and liquid at working temperature, surrounds the spark plug, conducting heat to a water jacket, while the pre-chamber body is coated with a non-thermal-conductive substance to enhance insulation and prevent heat loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional insulation materials with low thermal conductivity are used in the pre-chamber, then heat loss is reduced and thermal efficiency is improved, but the spark plug cannot be effectively cooled and overheats

Engineering Contradiction:

Improveheat lossVSAvoidspark plug temperature

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The patent applies different thermal conductivity properties to different regions of the pre-chamber. The inner surface facing the combustion chamber uses low thermal conductivity material for insulation, while the spark plug region uses high thermal conductivity material for heat dissipation. This spatial differentiation of material properties resolves the contradiction between maintaining thermal efficiency and cooling the spark plug.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The pre-chamber is divided into distinct thermal zones: an insulated combustion chamber region and a cooled spark plug region. The partition wall separating these regions acts as a thermal barrier, allowing the combustion chamber to maintain high temperature for efficiency while the spark plug region can be cooled independently through the cylinder head water jacket.

Inventive Principle:

Principle #1Segmentation

2Temperature

If high thermal conductivity material is used to cool the spark plug, then the spark plug temperature is reduced, but heat loss from the pre-chamber increases and thermal efficiency decreases

Engineering Contradiction:

Improvespark plug temperatureVSAvoidheat loss

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent applies different thermal conductivity properties to different regions of the pre-chamber. The inner surface facing the combustion chamber uses low thermal conductivity material for insulation, while the spark plug region uses high thermal conductivity material for heat dissipation. This spatial differentiation of material properties resolves the contradiction between maintaining thermal efficiency and cooling the spark plug.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If the pre-chamber is heavily insulated to maintain thermal efficiency, then heat loss is reduced, but the overall engine cooling system becomes less effective

Engineering Contradiction:

Improveheat lossVSAvoidcooling efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The pre-chamber is divided into distinct thermal zones: an insulated combustion chamber region and a cooled spark plug region. The partition wall separating these regions acts as a thermal barrier, allowing the combustion chamber to maintain high temperature for efficiency while the spark plug region can be cooled independently through the cylinder head water jacket.

Inventive Principle:

Principle #1Segmentation

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 solution effectively cools the spark plug and maintains high thermal efficiency within the pre-chamber, as demonstrated by simulation results showing higher pressure and temperature inside the pre-chamber, leading to improved engine performance.

Implementation Method 1

the liquid thermal-conductive substance conducts heat from the spark plug to the water jacket

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the thermal-conductive substance is solid at room temperature and liquid at working temperature of the PC

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 3

the PC body is coated with a layer of non-thermal-conductive substance

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11359537B1Spark ignition engine, pre-chamber, and method for cooling a pre-chamber

Publication Date: 2022.06.14 SAUDI ARABIAN OIL CO

AI summary

A spark ignition engine includes: a pre-chamber (PC); a main chamber (MC); and a cylinder head coupled with a water jacket. The PC includes: a spark plug; and a PC body. The spark plug is surrounded by a jacket with thermal-conductive substance. The thermal-conductive substance is solid at room temperature and liquid at working temperature of the PC. At working temperature of the PC, the liquid thermal-conductive substance conducts heat from the spark plug to the water jacket. The PC body is coated with a layer of non-thermal-conductive substance.