Igniter Cooling Sleeve for Rotary Engine Thermal Management

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Solution Overview

Problem

Internal combustion engine igniters often fail due to inadequate cooling, leading to the igniter tip separating and being ingested into the combustion chamber, causing damage.

Innovation Solution

A rotary engine design incorporating a cooling sleeve around the igniter tip supporting portion to facilitate heat transfer from the igniter to the housing, preventing overheating and potential separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the igniter is subjected to high temperatures during combustion cycles, then the igniter can effectively ignite the fuel, but the igniter tip may separate from the igniter and be ingested into the combustion chamber

Engineering Contradiction:

Improveigniter reliabilityVSAvoidthermal damage to igniter

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A cooling sleeve is introduced as an intermediary component between the igniter and the combustion chamber environment. The cooling sleeve receives coolant flow and transfers heat away from the igniter, particularly protecting the tip supporting portion from thermal damage while allowing the igniter to function at operational temperatures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal parameters of the igniter are controlled by introducing coolant flow through the cooling sleeve. This changes the temperature distribution around the igniter, maintaining the tip supporting portion at a lower temperature to prevent separation while allowing the tip to reach ignition temperatures during operation

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the igniter tip is exposed to high temperatures for extended periods, then combustion can be maintained, but the igniter tip supporting portion may fail and cause engine damage

Engineering Contradiction:

Improvecontinuous operation capabilityVSAvoidigniter tip joint strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The cooling sleeve acts as a thermal mediator that protects the igniter tip supporting portion during continuous operation. By continuously removing heat from this critical area, the cooling sleeve prevents thermal degradation and maintains the structural strength of the joint between the tip and supporting portion

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling sleeve provides beforehand protection to the igniter tip supporting portion by pre-cooling and continuously managing thermal loads. This preventive cooling approach cushiones against thermal stress accumulation that would otherwise lead to failure during extended operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The cooling sleeve effectively manages heat transfer, reducing the risk of igniter tip failure and engine damage by maintaining a controlled temperature, ensuring reliable engine operation.

Implementation Method 1

the cooling sleeve defining a path of heat transfer between the tip supporting portion and the housing

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10514017B2Internal combustion engine with igniter cooling sleeve

Publication Date: 2019.12.24 PRATT & WHITNEY CANADA CORP

AI summary

An internal combustion engine including an igniter disposed at least partially within an aperture defined in a housing of the engine, the igniter having a body including a tip supporting portion and having a tip extending from the tip supporting portion. A cooling sleeve is disposed around the tip supporting portion, and the cooling sleeve defines a path of heat transfer between the tip supporting portion and the housing. The engine may be a rotary engine. A method for cooling an igniter of an internal combustion engine is also discussed.