Double-Pipe Muffler Multi-Frequency Acoustic Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mufflers can only muffle sound in one frequency, requiring separate designs for each frequency and necessitating multiple mufflers to address multiple frequencies effectively.
Innovation Solution
A double-pipe muffler structure with a cylindrical inner and outer pipe, featuring a clearance and communication holes that function as a side-branch muffler and Helmholtz resonator, allowing for the muffled of sounds in two or more frequencies while reducing the outer diameter for space efficiency and accommodating thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional resonant-type muffler with a single opening is used, then the structure is simple, but it can only muffle sound in one frequency
Solution Approach 1:
The single opening is segmented into multiple openings (first opening and second opening) at different positions on the inner pipe. Each opening creates a separate acoustic path with different resonance characteristics, enabling the muffler to effectively attenuate sounds across multiple frequency ranges while maintaining the basic double-pipe structure
Solution Approach 2:
The invention transitions from a single-dimensional acoustic path to a multi-dimensional acoustic network by adding openings at different positions and creating multiple communication paths between the inner and outer pipes. This dimensional expansion of the acoustic flow paths enables multi-frequency muffling capability
2Adaptability or versatility
If multiple separate mufflers are used to muffle sounds in multiple frequencies, then the muffling effectiveness across frequencies is improved, but the device complexity and installation space increase
Solution Approach 1:
Multiple muffling functions for different frequencies are merged into a single integrated double-pipe muffler structure. The inner pipe with multiple openings and the surrounding outer pipe work together as one unified device, combining what would traditionally require multiple separate mufflers into a single compact unit that reduces installation space
Solution Approach 2:
The double-pipe muffler structure is designed to perform multiple muffling functions simultaneously across different frequency ranges. The system universally handles various sound frequencies through its multiple acoustic paths and resonance chambers, making a single device capable of replacing multiple specialized mufflers
3Strength
If the inner pipe and outer pipe are rigidly connected, then the structural strength is improved, but thermal expansion stress increases
Solution Approach 1:
The connection between the inner pipe and outer pipe is designed to be dynamic rather than rigidly fixed. The muffler allows for relative movement and thermal expansion between the two pipes while maintaining structural integrity, converting a static rigid connection into a dynamic adaptive connection that accommodates thermal effects
Solution Approach 2:
The design explicitly accounts for thermal expansion by allowing the inner and outer pipes to expand and contract independently. The structural configuration accommodates differential thermal movement between the pipes, preventing excessive stress concentration while maintaining overall structural strength
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
Enables effective muffling of multiple frequencies with a single muffler design, reducing the need for multiple units and allowing for flexible installation, while minimizing stress concentration and maintaining reliable performance.
Implementation Method 1
The resonance pipe and the resonance chamber may function as a Helmholtz resonator due to the resonance pipe communicating with the first exhaust passage via the opening and due to the resonance chamber communicating with the first exhaust passage via the resonance pipe
Implementation Method 2
This configuration provides a side-branch muffler with the clearance communicated with the first exhaust passage through the opening and the communication hole, and therefore enables muffling of sounds in two or more frequencies by the side branch
Data Source
AI summary
A muffler including a double-pipe structure to muffle sounds in two or more frequencies is provided. The muffler includes an inner and outer pipes with a clearance therebetween. The inner pipe includes a first and second outer surfaces, and, at one end, an opening communicating with the outer pipe. The clearance communicates with an exhaust passage via the opening. The second outer surface forms the opening and is situated closer to the center of the inner pipe than the first outer surface is. A space between the inner and outer pipes is closed due to a contact between the first outer surface and an inner-circumferential surface of the outer pipe. A part of the clearance is formed between the first outer surface and the inner-circumferential surface. The outer-circumferential surfaces of the inner pipe include at least one communication hole that communicates the inner pipe with the clearance.