Variable-Area Fuel Injector with Swirler for Uniform Spray
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Solution Overview
Problem
Conventional variable-area fuel injectors suffer from poor spray circumferential uniformity and patternation, leading to non-uniform fuel distribution, hot spots, reduced fuel efficiency, and poor emissions quality in air-breathing engines, and premature failure in applications like automotive exhaust treatment.
Innovation Solution
A variable-area fuel injector design featuring a pintle with a conical head and spring, combined with a fuel swirler that creates a swirling action, ensuring optimal patternation by increasing the exit orifice area with pressure and centering the pintle for uniform fuel flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional variable-area fuel injectors use slots or holes to feed fuel to the fuel manifold, then the injector structure is simple, but the spray circumferential uniformity deteriorates due to wake formation
Solution Approach 1:
The patent removes the traditional slots or holes from the fuel manifold design. Instead of using slots/holes to feed fuel, the invention uses a smooth-walled fuel manifold that eliminates the source of wake formation, thereby resolving the contradiction between structural simplicity and spray uniformity.
Solution Approach 2:
Rather than adding complex flow control features to improve uniformity, the invention inverts the approach by removing flow-disrupting features (slots/holes) entirely. The solution lies in what is taken away rather than what is added, achieving both simplicity and uniformity.
2Adaptability or versatility
If conventional variable-area fuel injectors are used, then the injector provides good atomization over a wide range of flow rates, but the patternation deteriorates leading to non-uniform fuel distribution
Solution Approach 1:
The patent extracts and removes the slots or holes from the fuel manifold that cause wake formation and poor patternation. This removal maintains the variable-area injector's ability to handle wide flow rate ranges while eliminating the source of non-uniform fuel distribution.
Solution Approach 2:
The invention changes the flow regime parameters by eliminating flow disruption sources. The smooth-walled manifold alters the flow characteristics to prevent wake formation, thereby improving patternation while maintaining adaptability across flow rates.
3Device complexity
If conventional variable-area fuel injectors operate without wake prevention, then the device complexity is low, but hot spots form causing thermal distress and engine failure
Solution Approach 1:
The patent takes out the slots or holes that generate wakes and subsequent hot spots. By removing these flow-disrupting features, the invention prevents thermal distress and engine failure while maintaining a relatively simple manifold configuration.
Solution Approach 2:
The invention applies preliminary anti-action by preventing wake formation at its source through the smooth-walled manifold design. This proactive approach prevents hot spot formation before it can cause thermal distress, rather than attempting to mitigate the effects after they occur.
4Ease of manufacture
If conventional variable-area fuel injectors allow wake formation, then the manufacturing is simpler, but fuel efficiency deteriorates due to rich regions in combustors
Solution Approach 1:
The patent removes slots or holes from the manifold design, achieving both ease of manufacture (by reducing complex features) and improved fuel efficiency (by eliminating wake-induced rich regions). The smooth-walled manifold is simpler to fabricate and simultaneously improves combustion efficiency.
Solution Approach 2:
While not directly applicable, this principle metaphorically represents the change in flow pattern quality. The smooth manifold transforms the flow regime from wake-filled to uniform, analogous to changing the 'quality color' of the flow, thereby improving fuel efficiency without complicating manufacture.
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 design enhances fuel spray uniformity, improves atomization, increases engine efficiency, reduces emissions, and extends the life of downstream components by preventing hot spots and fuel concentration issues.
Implementation Method 1
a fuel swirler configured to create a swirling action in the flow of pressurized fuel through the fuel manifold
Implementation Method 2
Above some threshold pressure, the pressurized fuel causes the conical head to move out of contact with the exit orifice of the body
Implementation Method 3
a pintle spring connected to the body. The pintle spring urges a tip of the pintle to seal against an exit orifice of the body
Data Source
AI summary
A fuel injector having a body with a bore, which defines a fuel manifold. The injector also has a variable-area injector arrangement having a pintle with a conical head and a pintle spring connected to the body. The pintle spring urges a tip of the pintle to seal against an exit orifice of the body, such that application of pressurized fuel within the body causes the pintle to move. Above some threshold pressure, the pressurized fuel causes the conical head to move out of contact with the exit orifice of the body. This, in turn, provides a corresponding variable area for passage of the pressurized fuel through the exit orifice about the conical head of the pintle. The injector further includes a swirler configured to create a swirling action in the flow of pressurized fuel through the fuel manifold, wherein the manifold is upstream of the exit orifice.