Active Pre-Chamber Ignition for Diluted Combustion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spark ignition engines face challenges with high cyclic variation and partial miss firing at part load conditions due to insufficient ignition kernel development and slow flame propagation, limiting efficiency improvements with diluted combustion.
Innovation Solution
The implementation of an active pre-chamber that generates high temperature hot jets to ignite the fuel-air mixture in the combustion main chamber, interacting with direct injection fuel sprays to enhance combustion efficiency and reduce emissions, without relying on a conventional spark plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional spark plug ignition is used in diluted combustion, then emissions can be reduced through lean operation, but ignition reliability deteriorates with high cyclic variation and partial misfiring
Solution Approach 1:
The combustion chamber is segmented into a pre-chamber and a main chamber. A small amount of fuel is burned in the pre-chamber to generate hot jets that are ejected into the main chamber to ignite the diluted fuel-air mixture. This segmentation allows reliable ignition in the pre-chamber while enabling efficient combustion of diluted mixtures in the main chamber, thus reducing emissions without sacrificing ignition reliability.
Solution Approach 2:
The pre-chamber acts as an intermediary device that prepares high-temperature ignition sources (hot jets) which then transfer energy to the main chamber to ignite the diluted mixture. This intermediary mechanism overcomes the insufficient ignition kernel development that occurs with conventional spark plugs in highly diluted conditions.
2Device complexity
If conventional spark plug ignition is used, then device complexity remains low, but flame propagation speed is insufficient leading to slow combustion
Solution Approach 1:
By dividing the combustion process into two stages (pre-chamber combustion followed by main chamber combustion), the system achieves rapid flame propagation through the ejection of high-velocity hot jets into the main chamber. This segmented approach dramatically accelerates combustion compared to conventional single-chamber spark ignition, while the added complexity is limited to the pre-chamber structure and hot jet ejection mechanism.
3Productivity
If diluted combustion is used to reduce emissions, then fuel efficiency can be improved, but ignition kernel development becomes insufficient causing high cyclic variation
Solution Approach 1:
The pre-chamber combustion separates the ignition function from the main combustion process. A small, rich fuel-air mixture is burned in the pre-chamber to generate consistent hot jets, while the main chamber handles the diluted fuel-air mixture combustion. This segmentation ensures reliable ignition kernel development in the pre-chamber and efficient diluted combustion in the main chamber, achieving both high fuel efficiency and consistent ignition across cycles.
Solution Approach 2:
The pre-chamber performs preliminary combustion of a small fuel charge to generate high-temperature hot jets before the main combustion event. This preliminary action creates favorable conditions for igniting the diluted mixture in the main chamber, ensuring consistent ignition kernel development even when the main chamber operates with highly diluted mixtures for improved fuel efficiency.
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 solution improves ignition reliability, reduces unburnt fuel in exhaust, decreases emissions, and prevents engine knocking, thereby increasing engine efficiency across a wide operating range and reducing sensitivity to misfiring.
Implementation Method 1
a spark plug configured to ignite a fuel-air mixture in the active pre-chamber
Implementation Method 2
high energy flame jets are ejected from the prechamber into a combustion main chamber
Implementation Method 3
a plurality of holes arranged circumferentially around a lower end of the active pre-chamber, the plurality of holes being configured to provide fluid communication between the central chamber and a combustion main chamber
Data Source
AI summary
A fuel ignition device for an engine having a plurality of cylinders. The fuel ignition device including an active pre-chamber, the active pre-chamber further including a fuel inlet for introducing fuel into the active pre-chamber, a spark plug configured to ignite a fuel-air mixture in the active pre-chamber, and a plurality of holes arranged circumferentially around a lower end of the active pre-chamber, the plurality of holes being configured to provide fluid communication between the central chamber and a combustion main chamber of the gas engine.