Ducted Combustion System Fuel Jet Guidance
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Solution Overview
Problem
Modern internal combustion engines face challenges in achieving uniform fuel/air mixing, leading to suboptimal combustion efficiency and increased soot formation due to inadequate fuel and air interaction within the combustion chamber.
Innovation Solution
A ducted combustion system utilizing a conical shaped duct structure within the combustion chamber to direct fuel jets, ensuring uniform fuel/air mixing by altering fluid dynamics and preventing entrainment of combustion products, thereby optimizing the lift-off length and reducing soot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fuel is directly injected into the combustion chamber without ducts, then the system structure is simple, but fuel/air mixing is inadequate leading to soot formation
Solution Approach 1:
The duct structure acts as an intermediary component between the fuel injector and the combustion chamber. It channels the fuel jet through a controlled path with integrated fins that enhance mixing with air, preventing direct uncontrolled injection while maintaining structural feasibility. This mediator structure resolves the contradiction by providing the necessary mixing function without requiring complete system redesign.
2Device complexity
If conventional fuel injection is used, then the device complexity is low, but fuel/air mixing uniformity is poor
Solution Approach 1:
The duct structure is segmented into multiple fins disposed around the fuel jet path. These fins divide the combustion chamber space and create multiple mixing zones, enhancing fuel/air interaction. The segmentation approach improves mixing uniformity by breaking down the single injection stream into multiple controlled flow paths while adding only moderate structural complexity.
Solution Approach 2:
The duct structure extends into the third dimension by projecting fins radially outward from the fuel injection axis. This dimensional addition creates circumferential mixing zones that were not present in conventional planar injection systems, significantly improving fuel/air mixing uniformity without proportionally increasing device complexity.
3Ease of operation
If fuel jets are injected without duct guidance, then the system is simple to operate, but combustion efficiency is suboptimal
Solution Approach 1:
The duct structure with fins is designed to automatically guide the fuel jet and promote self-mixing with surrounding air through the fin geometry. The structure leverages the natural momentum and turbulence of the injected fuel to drive the mixing process without requiring additional actuators or complex control systems, maintaining ease of operation while improving combustion 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
The system achieves a substantially uniform fuel/air mixture, reducing soot formation and emissions by inhibiting the entrainment of combustion products and maintaining a lower equivalence ratio at the flame lift-off length, thereby enhancing combustion efficiency.
Implementation Method 1
directing fuel jets, ensuring uniform fuel/air mixing by altering fluid dynamics
Implementation Method 2
inhibiting the entrainment of combustion products
Implementation Method 3
a fuel injector, which is associated with the cylinder and has an orifice disposed such that it can directly inject fuel into the combustion chamber
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 a plurality of orifices, the plurality of orifices injecting fuel into the combustion chamber as a plurality of fuel jets. The system includes a duct structure defining a plurality of ducts and disposed within the combustion chamber between the flame deck surface and the piston top surface, the plurality of ducts being disposed such that each of the plurality of fuel jets at least partially enters one of the plurality of ducts upon being injected into the combustion chamber.