Glow Plug Igniter Sealing Combustor Liner Gap

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Solution Overview

Problem

Spark plugs in gas turbine engines face reliability issues in wet conditions and low temperatures, and are costly, necessitating an alternative igniter solution that can reliably ignite air and fuel mixtures across varying conditions.

Innovation Solution

A glow plug-based igniter system is introduced, comprising a base secured to the engine casing, a glow plug heater rod extending into the combustor, and a combustor liner plug that bridges the gap between the heater rod and the combustor liner, enhancing ignition reliability and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spark plugs are used to ignite air and fuel mixture, then ignition function is provided, but reliability deteriorates in wet conditions and low temperatures

Engineering Contradiction:

Improveignition reliabilityVSAvoidwet conditions and low temperature effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A combustor liner plug is introduced as an intermediary component between the glow plug heater rod and the combustion chamber. This plug extends into the combustion chamber and surrounds the heater rod, creating a controlled environment that shields the ignition process from harmful external conditions such as wetness and cold, thereby improving ignition reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a glow plug heater rod that can be replaced more easily and cost-effectively than traditional spark plugs. The heater rod is designed as a consumable component that can be serviced without replacing the entire igniter assembly, reducing maintenance costs and improving reliability through easier replacement

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If spark plugs are used for ignition, then ignition function is achieved, but cost increases

Engineering Contradiction:

Improveignition reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The igniter system is segmented into distinct replaceable components: a base portion that remains installed and a glow plug heater rod that can be independently replaced. This segmentation allows the expensive ignition function to be maintained while reducing overall system cost by separating the reusable base from the consumable heating element

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The glow plug heater rod is designed as a disposable or easily replaceable component with lower cost than traditional spark plugs. By using off-the-shelf heater rod components and a simple base assembly, the overall system cost is reduced while maintaining reliable ignition function

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If a glow plug heater rod is used instead of spark plug, then ignition reliability improves, but device complexity increases

Engineering Contradiction:

Improveignition reliabilityVSAvoidigniter structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The base portion of the igniter is designed to provide multiple functions: electrical connection to the heater rod, mechanical support, sealing against the combustor liner, and structural mounting to the engine. By consolidating these functions into a single universal base component, the overall device complexity is reduced despite using a glow plug heater rod

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If combustor liner plug is added to bridge gap between heater rod and aperture, then ignition reliability improves, but device complexity increases

Engineering Contradiction:

Improveignition reliabilityVSAvoidigniter assembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The combustor liner plug is merged with the base portion to form an integrated assembly. The plug extends from the base into the combustion chamber, combining the sealing function at the aperture with the ignition function in a single unified structure, thereby minimizing additional complexity while improving reliability

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

The glow plug-based igniter system improves ignition reliability across wet and cold conditions, reduces costs by utilizing off-the-shelf components with adapters, and effectively ignites air and fuel mixtures, ensuring consistent engine performance.

Implementation Method 1

a glow plug heater rod extending from the base along an axis and terminating in a rod end

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11692489B2Igniter for gas turbine engine

Publication Date: 2023.07.04 PRATT & WHITNEY CANADA CORP

AI summary

A method of servicing a gas turbine engine having an igniter socket, the method comprising: inserting a glow plug into the igniter socket of the gas turbine engine until a rod end of a glow plug heater rod of the glow plug is exposed to a combustion chamber of the gas turbine engine; and blocking a gap between the glow plug heater rod and an aperture defined in a combustor liner of the gas turbine engine to block fluid communication between the combustion chamber and an environment outside the combustion chamber via the aperture.