Pre-Chamber Combustion Vortex Control via Flow Segmentation

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Solution Overview

Problem

The configuration of internal combustion engines with pre-chambers often results in slow combustion due to opposing flows that weaken the vortex in the pre-chamber, leading to inefficient flame propagation and reduced thermal efficiency.

Innovation Solution

A structure is implemented in the main combustion chamber to suppress opposing flows into the pre-chamber, specifically using a baffle wall or recess to impede squish flows from the exhaust port side, while enhancing tumble flows from the intake port side, maintaining a strong vortex for rapid combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the pre-chamber is provided inside the main combustion chamber with communicating holes, then flame propagation is enhanced, but opposing flows weaken the vortex and slow combustion

Engineering Contradiction:

Improvecombustion speedVSAvoidvortex strength

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The communicating holes are divided into two groups: first communicating holes that allow tumble flow to enter the pre-chamber and form a vortex, and second communicating holes that are blocked by a baffle wall to prevent squish flow from entering. This segmentation of flow paths resolves the contradiction by allowing beneficial flow while blocking harmful flow.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A baffle wall is introduced as an intermediary structure between the second communicating holes and the pre-chamber. The baffle wall selectively blocks the squish flow (harmful) while allowing the tumble flow (beneficial) to pass through, thus maintaining vortex strength while enabling flame propagation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If tumble flow is allowed to flow into the pre-chamber through communicating holes, then a vortex is generated that stimulates flame propagation, but squish flow from the exhaust port side opposes the vortex and weakens it

Engineering Contradiction:

Improveflame propagation speedVSAvoidopposing flow effect

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The baffle wall acts as an intermediary that selectively filters flow paths. It allows the tumble flow (which generates beneficial vortex) to enter the pre-chamber through first communicating holes, while blocking the squish flow (which creates harmful opposing effect) from entering through second communicating holes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Different regions of the pre-chamber system are given different functions: the first communicating holes are designed to receive tumble flow for vortex generation, while the second communicating holes are blocked to prevent squish flow entry. This local differentiation resolves the contradiction by optimizing each region's contribution to flame propagation.

Inventive Principle:

Principle #3Local quality

3Speed

If the ignition plug is positioned at the upper end of the pre-chamber with communicating holes at the lower end, then flame can propagate through the holes, but the long distance causes slow combustion that may push unburnt mixture into the main chamber

Engineering Contradiction:

Improvecombustion completion speedVSAvoiddistance between ignition plug and communicating holes

Core Design Contradiction:

SpeedVSLength of moving object

Solution Approach 1:

The vortex is generated in advance by allowing tumble flow to enter the pre-chamber through the first communicating holes before ignition occurs. This preliminary vortex formation ensures that when the ignition plug ignites the mixture, the pre-existing vortex immediately stimulates rapid flame propagation, preventing unburnt mixture from being pushed into the main combustion chamber.

Inventive Principle:

Principle #10Preliminary 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

This configuration ensures rapid combustion in the pre-chamber and main combustion chamber, improving thermal efficiency by preventing unburnt mixture gases from being pushed into the main chamber and enhancing flame propagation.

Implementation Method 1

The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow

Methodology Applied

Scientific EffectVortex: Vortex Ring

Implementation Method 2

an ignition plug ignites a mixture gas inside the pre-chamber. A flame jet is injected into the main combustion chamber from the pre-chamber through a plurality of nozzles

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11215109B2Internal combustion engine with pre-chamber

Publication Date: 2022.01.04 MAZDA MOTOR CORP

AI summary

An internal combustion engine is provided with a pre-chamber provided inside a main combustion chamber. The pre-chamber includes an ignition plug, and a casing provided to a ceiling part to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber. A tumble flow of a mixture gas is formed inside the main combustion chamber. A plurality of communicating holes are formed in the casing, and include a first communicating hole opening to an intake port side and a second communicating hole opening to an exhaust port side. The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow. The main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex flowing into the pre-chamber through the second communicating hole.