Ducted Combustion System Tabs for Fuel Mixing
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Solution Overview
Problem
Modern internal combustion engines face challenges in achieving uniform fuel/air mixtures, leading to suboptimal combustion efficiency and increased soot formation due to inadequate mixing, which existing ducted combustion systems have not fully addressed.
Innovation Solution
The implementation of a ducted combustion system with tubular ducts disposed within the combustion chamber, featuring structural tabs and various configurations such as perforations, mesh, or convergent/divergent structures to enhance fuel/air mixing and prevent entrainment of combustion products, directing fuel jets into these ducts to achieve a more uniform and lean mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ducted combustion systems with fins are used to improve fuel/air mixing, then combustion efficiency is improved, but soot formation is not sufficiently reduced
Solution Approach 1:
The duct structure is segmented into multiple functional zones: an upstream region with fins for fuel/air mixing, a middle section for flame propagation, and a downstream region with tabs for flow control. This segmentation allows each zone to perform its specific function optimally, achieving both efficient combustion and reduced soot formation through proper zone management.
Solution Approach 2:
The duct acts as an intermediary structure between the fuel injector and the combustion chamber. It provides a controlled environment where fuel and air can mix thoroughly before combustion, and where combustion products can be managed downstream, thereby reducing direct soot formation in the main combustion chamber.
2Ease of manufacture
If fuel jets are directly injected into the combustion chamber, then injection simplicity is maintained, but fuel/air mixing is inadequate leading to high soot
Solution Approach 1:
The duct structure is nested within the combustion chamber, with the fuel injector positioned to inject fuel directly into the duct. This nested arrangement allows the simple direct injection system to be combined with the complex mixing and flow control functions of the duct, achieving low soot formation without compromising injection simplicity.
3Device complexity
If ducts without tabs are used, then device complexity is reduced, but fuel/air mixing uniformity is insufficient
Solution Approach 1:
Tabs are added locally at the downstream end of the duct rather than throughout the entire structure. This localized modification creates specific flow control zones that enhance fuel/air mixing uniformity without requiring complex modifications to the entire duct system, thus maintaining relative simplicity while achieving improved mixing.
4Device complexity
If conventional combustion chambers are used, then chamber simplicity is maintained, but flame lift-off length is insufficient leading to poor combustion efficiency
Solution Approach 1:
The duct structure performs preliminary fuel/air mixing and flame stabilization actions before the main combustion event in the chamber. By preparing the fuel/air mixture and establishing proper flame lift-off length in the duct, the main combustion chamber can operate more efficiently without requiring complex modifications to its basic structure.
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 improves combustion efficiency by extending flame lift-off lengths, reducing soot emissions, and lowering equivalence ratios, resulting in more uniform fuel/air mixtures and reduced soot formation within the combustion chamber.
Implementation Method 1
upstream regions of a direct-injected fuel jet may be affected by faster and more uniform mixing
Implementation Method 2
The fuel jets may be channeled into the ducts, which may improve fuel combustion because upstream regions of a direct-injected fuel jet may be affected by faster and more uniform mixing
Implementation Method 3
an inhibition or reduction of entrainment of combustion products from downstream regions of the same or neighboring jets
Data Source
AI summary
A ducted combustion system is disclosed. The ducted combustion system includes a combustion chamber bound by a flame deck surface of a cylinder head of an internal combustion engine and by a piston top surface of a piston disposed within the internal combustion engine. The system includes a fuel injector including one or more orifices, the one or more orifices injecting fuel into the combustion chamber as at least one fuel jet. The system includes at least one duct disposed within the combustion chamber between the flame deck surface and the piston top surface, the at least one duct including one or more structural tabs proximate to an outlet of the at least one duct and being disposed such that the at least one fuel jet, at least partially, enters one of the at least one duct upon being injected into the combustion chamber.