Engine Fuel Nozzle Coking Prevention via Periodic Flow

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Solution Overview

Problem

In engines with multistage fueling systems, stagnant fuel in unused fuel stages can coking due to high temperatures, leading to nozzle clogging and maintenance issues.

Innovation Solution

Operating the engine at low power by supplying fuel through a first set of nozzles while periodically supplying a controlled amount of fuel to unused nozzles to prevent coking, using a processing unit and computer-readable memory to determine and manage the fuel flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If fuel is supplied only through the first set of fuel nozzles during low power operation, then the engine operates efficiently at low power, but the second set of fuel nozzles experience fuel coking due to stagnant fuel exposure to high temperatures

Engineering Contradiction:

Improvelow power operationVSAvoidfuel nozzle coking

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The system implements periodic action by switching between first and second sets of fuel nozzles in alternating intervals. During low power operation, the controller supplies fuel through the first set of nozzles for a first interval, then switches to the second set of nozzles for a second interval, preventing stagnant fuel from coking any single nozzle set while maintaining efficient low power operation.

Inventive Principle:

Principle #19Periodic action

2Reliability

If fuel is periodically supplied to the unused second manifold to prevent coking, then fuel coking is impeded, but additional fuel consumption occurs

Engineering Contradiction:

Improvefuel nozzle coking preventionVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The system applies partial action by supplying fuel to the second manifold only during specific periodic intervals rather than continuously. The controller determines optimal intervals and durations based on engine operating conditions, providing just enough fuel flow to prevent coking without excessive fuel consumption. This partial fueling approach balances reliability with fuel efficiency.

Inventive Principle:

Principle #16Partial or excessive action

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

Prevents fuel coking in unused fuel stages by maintaining a flow of fresh fuel, reducing the need for costly cleaning and replacement of nozzles, and ensuring engine efficiency.

Implementation Method 1

supplying the amount of fuel periodically to the at least one second manifold... to impede fuel coking of the second set of fuel nozzles

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentUS11713723B2Method and system for operating an engine

Publication Date: 2023.08.01 PRATT & WHITNEY CANADA CORP

AI summary

Systems and methods for operating an engine are described herein. The engine is operated at low power by supplying fuel to a combustor through a first set of fuel nozzles of at least one first manifold and without supplying fuel to the combustor through a second set of fuel nozzles of at least one second manifold. An amount of fuel to at least in part fill the at least one second manifold to impede fuel coking of the second set of fuel nozzles is determined. The amount of fuel is periodically supplied to the at least one second manifold.