UAV Muffler Resilient Mounting Thermal Expansion
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Solution Overview
Problem
Compact mufflers for small internal combustion engines, particularly those in UAVs, face challenges in achieving aerodynamic efficiency while accommodating thermal expansion and vibration, and maintaining a secure connection to the engine.
Innovation Solution
A muffler design with a resilient coupling or preload mechanism at the second end section to resist movement relative to the engine, preventing the connection from opening due to thermal expansion or contraction, and an elongate, arcuate body that can be mounted within the UAV fuselage with an exposed surface for airflow cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the muffler is mounted within the UAV fuselage to be exposed to airflow for cooling, then the cooling efficiency is improved, but the aerodynamic efficiency deteriorates
Solution Approach 1:
The muffler is positioned within the fuselage interior rather than externally mounted, utilizing the three-dimensional space inside the aircraft body. This internal placement allows the muffler to be cooled by airflow passing through or near it within the fuselage, while maintaining a streamlined external surface that preserves aerodynamic efficiency.
2Reliability
If the muffler is allowed to move freely to accommodate thermal expansion, then the reliability is improved, but the connection stability deteriorates
Solution Approach 1:
The mounting system utilizes elastomeric materials that change their mechanical properties with temperature. As the muffler heats up and expands, the elastomeric mounting elements soften and deform, accommodating the thermal expansion. As the muffler cools down, the elastomeric material stiffens and returns to its original shape, maintaining secure connection. This dynamic parameter change allows the system to adapt to thermal cycles while maintaining both reliability and stability.
3Stability of the object's composition
If the muffler connection is made rigid to prevent opening under thermal stress, then the connection stability is improved, but the ability to accommodate thermal expansion deteriorates
Solution Approach 1:
The mounting system employs elastomeric elements that function as flexible mounting structures. These elastomeric components can deform and flex to accommodate thermal expansion and contraction of the muffler body, while still providing sufficient mechanical strength to maintain the connection. The flexibility of these elements allows the system to absorb dimensional changes without compromising connection integrity or stability.
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 muffler effectively reduces noise emissions, maintains a secure connection during thermal changes, and allows for airflow cooling, enabling the engine to operate at higher exhaust gas temperatures without compromising reliability, while minimizing aerodynamic disruption.
Implementation Method 1
The resilient coupling may comprise one or more springs operably connected to the second end section. The spring(s) may comprise one or more leaf springs.
Implementation Method 2
the feature of the second end section being mounted to resist movement with respect to the engine may comprise a yielding resistance. The yielding resistance may be provided by a resilient coupling.
Implementation Method 3
it may be desirable for the muffler to be exposed to airflow generated through movement of the UAV while in flight, whereby the airflow can be used to assist with cooling of the muffler
Data Source
AI summary
A muffler (40) devised particularly for use with an engine of the type used on unmanned aerial vehicles (UAVs), and a UAV (10) having an engine (30) fitted with the muffler (40). The muffler (40) comprises a body (51) having an interior chamber (60). The muffler body (51) has a first end section (53) and a second end section (55). The first end section (51) is adapted for mounting onto the engine (31) by way of a first mount (81), with the interior chamber (60) in communication with an exhaust outlet of the engine (31) to receive exhaust flow therefrom. The second end section (53) is adapted to be mounted by way of a second mount (82) in a manner resisting movement with respect to the engine (31). In one arrangement, the second mount (82) is configured to yieldingly resist movement with respect to the engine (30). In another arrangement, the second mount (82) is configured to mount the second end section (55) under a preload resisting movement of the second end section with respect to the engine (30).