Ducted Combustion Flow Field Preparation for Soot Reduction
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Solution Overview
Problem
Modern combustion engines face challenges in achieving optimal fuel/air mixing, leading to suboptimal combustion efficiency and increased soot formation due to inadequate flame lift-off length, which existing ducted combustion systems have not fully addressed.
Innovation Solution
The implementation of a ducted combustion system with a flow field air stream within the ducts, configured to direct fuel jets in a manner that maintains or increases their velocity and momentum, thereby extending flame lift-off length and improving fuel/air mixing by preventing stagnant air from hindering fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ducted combustion systems are used to improve fuel/air mixing, then mixing uniformity is improved, but flame lift-off length is insufficient leading to increased soot formation
Solution Approach 1:
The patent introduces a flow field generation system that creates a controlled air flow pattern within the combustion chamber before fuel injection. This preliminary action prepares the combustion environment by establishing appropriate flow conditions that promote both uniform mixing and extended flame lift-off length, thereby reducing soot formation while maintaining mixing quality.
2Object-affected harmful factors
If flame lift-off length is increased to reduce soot accumulation, then soot formation is reduced, but fuel/air mixing may become suboptimal
Solution Approach 1:
The patent modifies key flow parameters by introducing a flow field generation system that controls air flow velocity, direction, and distribution. By adjusting these flow parameters, the system achieves extended flame lift-off length for soot reduction while simultaneously maintaining optimal fuel/air mixing conditions through controlled flow patterns.
3Device complexity
If stagnant air is present in the combustion chamber, then device complexity is reduced, but fuel injection velocity and momentum are hindered
Solution Approach 1:
The flow field generation system utilizes the existing combustion chamber structure and operating conditions to create beneficial flow patterns. The system leverages the natural combustion process and available air supply to generate flow fields that enhance fuel injection performance without requiring additional complex external components or systems.
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 approach significantly reduces soot production and enhances combustion efficiency by ensuring uniform fuel/air mixing and extended flame lift-off length, compared to systems without flow field generation.
Implementation Method 1
configured to direct fuel jets in a manner that maintains or increases their velocity and momentum
Implementation Method 2
having a flow direction that is substantially similar to the fuel flow direction
Implementation Method 3
upstream regions of a direct-injected fuel jet may be affected by faster and more uniform mixing
Implementation Method 4
fuel for combustion is directly injected into the combustion chamber
Data Source
AI summary
A ducted combustion system includes a combustion chamber and a fuel injector in fluid connection with the combustion chamber, which includes an orifice opening from an injector tip of the fuel injector, the orifice injecting fuel into the combustion chamber as a fuel jet, the fuel jet flowing, within the combustion chamber, in a fuel flow direction. The system includes at least one duct disposed within the combustion chamber, the at least one duct being disposed such that the fuel jet, at least partially, enters one of the at least one ducts upon being injected into the combustion chamber. The at least one duct may be configured for having a flow field air stream within the duct, prior to entrance of the fuel jet, the flow field air stream having a flow direction that is substantially similar to the fuel flow direction.