Oval Pre-Chamber Flow Channels for Lean Combustion
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Solution Overview
Problem
Existing pre-chamber designs in gaseous fuel internal combustion engines face challenges in achieving consistent and thorough combustion using lean fuel-air mixtures, particularly in large-bore engines, where the geometry of flow transfer channels limits the efficiency of flame propagation from the pre-chamber to the main combustion chamber.
Innovation Solution
The pre-chamber body incorporates flow transfer channels with oval inner and outer openings, configured as converging-diverging nozzles, which enhance the stability and broadness of the flame jet into the main combustion chamber, allowing for improved ignition and combustion without significant increases in space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flow transfer channels with circular cross-sections are used, then the structure is simple and easy to manufacture, but the flame jet stability and broadness are insufficient, limiting combustion efficiency
Solution Approach 1:
The patent applies asymmetry by changing the flow transfer channel cross-section from circular to oval shape. The oval cross-section has different dimensions in orthogonal directions (first dimension and second dimension), creating an asymmetric geometry that optimizes flame jet broadness and stability. This asymmetric design allows the flame to propagate more effectively into the main combustion chamber while maintaining manufacturing feasibility through standard molding processes.
Solution Approach 2:
The patent implements parameter changes by modifying the geometric parameters of the flow transfer channel, specifically the cross-sectional shape from circular to oval. The oval cross-section is defined by varying the dimensions along different axes (first dimension versus second dimension), which changes the flow characteristics and flame propagation patterns. This parameter optimization enhances combustion efficiency without fundamentally altering the channel structure or requiring complex manufacturing processes.
2Reliability
If the flow transfer channels are designed to broaden the flame jet, then combustion efficiency improves, but the space requirements and pre-chamber volume increase
Solution Approach 1:
The patent applies local quality by optimizing the geometry specifically at the flow transfer channel openings rather than increasing the overall pre-chamber volume. The oval cross-section with different first and second dimensions creates localized flow optimization at the channel exits, broadening the flame jet where it is most needed for ignition. This localized geometric modification achieves improved ignition efficiency without expanding the pre-chamber cavity or requiring additional space.
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 design optimizes the flow and stability of the pre-chamber body, leading to enhanced ignition and combustion efficiency in gaseous fuel internal combustion engines, particularly by broadening the flame jet and maintaining structural integrity through innovative geometric configurations.
Implementation Method 1
Each flow transfer channel may extend along a flow transfer channel axis from an inner opening via a throat section to an outer opening. A cross-section of the flow transfer channels may converge from a first cross section of the inner opening to a second cross-section of the throat section, and diverges from the second cross-section to a third cross-section of the outer opening along the flow transfer channel axis.
Data Source
AI summary
A pre-chamber body for an engine is disclosed. The pre-chamber body may have a pre-chamber. The pre-chamber body may also have flow transfer channels fluidly connecting the pre-chamber and an exterior of the pre-chamber body. Each flow transfer channel extends along a flow transfer channel axis (B) from an inner opening via a throat section to an outer opening. A cross-section of the flow transfer channels converges from a first cross section (A1) of the inner opening to a second cross-section (A2) of the throat section and diverges from the second cross-section (A2) to a third cross-section (A3) of the outer opening along the flow transfer channel axis (B). At least one of the inner opening and the outer opening has an oval shape with a maximum diameter (a1, a3) and a minimum diameter (b1, b3), the maximum diameter (a1, a3) being greater than the minimum diameter (b1, b3).