Exhaust Muffler Secondary Pipe Structure for High-Frequency Noise
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Solution Overview
Problem
Existing exhaust muffler technologies using glass and mineral fibers for acoustic insulation in internal combustion engines face environmental, health, and safety concerns, and are costly, while alternative methods like bagged/brick roving are not ideal.
Innovation Solution
An exhaust muffler design featuring a hollow body with an exhaust pipe and a secondary pipe filled with sound-absorbing material, connected by baffles that create chambers for sound attenuation, allowing exhaust gases to flow through and back, with optional orifices and capped ends for secure sound absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If glass fibers and mineral fibers are packed into the muffler for acoustic insulation, then sound absorption performance is improved, but environmental, health, and safety concerns arise
Solution Approach 1:
The invention extracts the sound-absorbing function from traditional loose fiber packing and relocates it to a dedicated secondary pipe filled with sound-absorbing material. This separates the acoustic function from the exhaust flow path, eliminating direct contact between workers and harmful fibers during installation while maintaining sound absorption performance.
Solution Approach 2:
The secondary pipe acts as an intermediary container that holds the sound-absorbing material, mediating between the exhaust gases and the acoustic insulation. This intermediary structure allows the sound-absorbing material to perform its function without requiring direct exposure to exhaust gases or manual handling of loose fibers.
2Ease of manufacture
If bagged/brick roving is used for acoustic insulation, then installation cost is reduced, but acoustic performance and ideal functionality are compromised
Solution Approach 1:
The invention segments the muffler into distinct functional zones: the exhaust pipe for gas flow and the secondary pipe for acoustic insulation. This segmentation allows each component to be optimized independently, with the secondary pipe filled with sound-absorbing material to deliver superior acoustic performance compared to traditional bagged/brick roving methods.
3Object-affected harmful factors
If a compact structure with secondary pipe is used, then noise attenuation effectiveness is improved, but device complexity increases
Solution Approach 1:
The invention implements a nested structure where the secondary pipe containing sound-absorbing material is positioned within the hollow body of the muffler, concentric or offset from the exhaust pipe. This nesting arrangement achieves effective noise attenuation in a compact configuration without requiring multiple separate components or complex assembly procedures.
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 effectively attenuates high-frequency noise by utilizing sound-absorbing materials within a compact structure, reducing noise pollution and addressing environmental and safety concerns without the drawbacks of traditional methods.
Implementation Method 1
a secondary pipe is disposed within the hollow body, such that the secondary pipe is filled with a sound absorbing material
Data Source
AI summary
An exhaust muffler includes a hollow body that at least partially houses an exhaust pipe. The exhaust pipe is adapted to allow a flow of exhaust gases therethrough. Further, the exhaust pipe defines a plurality of orifices on the exhaust pipe such that the exhaust gases flowing through the exhaust pipe can flow out of the exhaust pipe within the hollow body and/or flow back into the exhaust pipe from the hollow body through the plurality of orifices. A secondary pipe is disposed within the hollow body and filled with a sound absorbing material. At least one baffle is engaged with the exhaust pipe and the secondary pipe to allow at least one of the exhaust pipe and the secondary pipe to pass therethrough.