Shielding Wall Stabilizes Hydrogen Flame Kernel

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Gaseous hydrogen fuel engines face challenges in maintaining precise ignition timing and combustion phasing due to the high flame speed of hydrogen, which can extinguish the flame kernel formed by spark plugs, and require efficient clearing of residual combustion gases to prevent misfires and combustion phasing errors.

Innovation Solution

A gaseous fuel engine system with a shielding wall around the igniter pocket to protect the flame kernel from extinguishment and fluidly connect it to the cylinder to clear residual gases, allowing for a balanced flow field that stabilizes the ignition charge formation and limits combustion phasing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pocket is fully shielded from cylinder gas flow to protect the flame kernel, then flame kernel stability improves, but residual combustion gases cannot be cleared efficiently

Engineering Contradiction:

Improveflame kernel stabilityVSAvoidresidual gas clearance efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The shielding wall is segmented with openings that allow selective gas flow. The wall divides the pocket into regions with different flow characteristics, enabling simultaneous protection of the flame kernel in the shielded region and clearance of residual gases through the openings.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pocket have different shielding qualities. The area around the spark electrodes has strong shielding for flame kernel protection, while other regions have openings for gas clearance. This local differentiation allows both functions to coexist.

Inventive Principle:

Principle #3Local quality

2Productivity

If the pocket is open to the cylinder for gas exchange, then residual combustion gases are cleared effectively, but the flame kernel becomes vulnerable to extinguishment

Engineering Contradiction:

Improveresidual gas clearance efficiencyVSAvoidflame kernel stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Residual gases are cleared from the pocket before the flame kernel is formed. The openings allow exhaust gases to be expelled during the exhaust stroke, preparing a clean environment for the next ignition event, while the shielding wall protects the subsequently formed flame kernel.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pocket alternates between phases of gas clearance and flame kernel formation/protection. During the exhaust stroke, openings enable gas flow out; during the compression and ignition strokes, the shielding wall dominates to protect the flame kernel. This periodic switching resolves the contradiction.

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If shielding is increased to protect the flame kernel, then combustion phasing precision improves, but gas flow restriction increases

Engineering Contradiction:

Improvecombustion phasing precisionVSAvoidgas flow restriction

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The shielding wall configuration allows dynamic gas flow adaptation. The openings provide pathways for gas flow when needed, while the shielding structure maintains flame kernel stability. This dynamic balance achieves precise combustion phasing without excessive flow restriction.

Inventive Principle:

Principle #15Dynamics

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 solution effectively shields the flame kernel from extinguishment while ensuring the clearance of residual gases, stabilizing ignition charge formation and reducing misfires and combustion phasing errors, enabling reliable ignition and efficient operation with gaseous hydrogen fuel.

Implementation Method 1

shields the pocket from gas flow in the cylinder sufficiently to establish within the pocket a flow field for protecting a flame kernel

Methodology Applied

Scientific EffectFlow field:

Implementation Method 2

shielding wall extends around the pocket and shields the pocket from gas flow in the cylinder

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

fluidly connecting the pocket to the cylinder sufficiently to clear the pocket of residual combustion gases

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 4

igniting the ignition charge via a flame kernel formed by energizing spark electrodes of the igniter

Methodology Applied

Scientific EffectElectrical discharge: Electric Spark

Implementation Method 5

igniting an ignition charge containing gaseous hydrogen fuel and air within the pocket via the flame kernel

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11994058B2Ignition charge formation stabilization in gaseous fuel engine system

Publication Date: 2024.05.28 CATERPILLAR INC

AI summary

Operating a gaseous fuel engine system includes urging a mixture containing a gaseous hydrogen fuel and air into a pocket in an igniter fluidly connected to a cylinder to form an ignition charge, and igniting the ignition charge via a flame kernel formed by energizing spark electrodes of the igniter. The method further includes igniting a main charge containing the gaseous hydrogen fuel via a flame jet of the ignition charge from the igniter. The pocket is shielded from the cylinder sufficiently to form within the pocket a flow field protecting the flame kernel, while fluidly connected to the cylinder sufficiently to clear the pocket of residual combustion gases.