Horizontal Side Branch Muffler for Compact Low-Frequency Attenuation
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Solution Overview
Problem
Conventional side branch mufflers struggle to effectively attenuate low-frequency sound waves in a compact design, often exceeding size limitations in automotive applications and requiring costly manufacturing processes to maintain sound wave attenuation across varying frequencies.
Innovation Solution
A side branch muffler design featuring elongated fluid passages with circumferentially spaced side regions and adjacent sound chambers, allowing for a wider range of sound attenuation without increasing overall height or length, and incorporating stop plates to tune specific frequencies, resulting in a subcompact and lightweight configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional side branch mufflers are designed to attenuate low-frequency sound waves, then sound attenuation effectiveness is improved, but the muffler size increases and exceeds size limitations in automotive applications
Solution Approach 1:
The patent transitions from conventional vertical arrangement of sound chambers to a horizontal extension configuration. The elongated fluid passage extends horizontally through the muffler body, with sound chambers positioned at opposite ends. This dimensional change allows the muffler to achieve the required sound wave attenuation path length without increasing vertical height, thereby fitting within automotive application space constraints while maintaining low-frequency sound attenuation effectiveness.
2Volume of moving object
If the muffler design is made compact to fit automotive applications, then size constraints are satisfied, but sound wave attenuation across varying frequencies becomes difficult to maintain
Solution Approach 1:
The patent divides the muffler interior into multiple distinct sound chambers positioned at opposite ends of the elongated fluid passage. These chambers are separated by internal partitions and configured with different characteristics to target specific frequency ranges. The segmentation allows each chamber to specialize in attenuating particular frequencies, enabling comprehensive frequency coverage within a compact horizontal footprint.
Solution Approach 2:
Different sections of the muffler are designed with locally optimized characteristics. The sound chambers at opposite ends of the horizontal passage have different volumes, shapes, and configurations tailored to attenuate specific frequency ranges. This local quality differentiation enables the compact muffler to maintain effective sound wave attenuation across varying frequencies by having each region specialized for its intended frequency band.
3Object-affected harmful factors
If complex baffle systems and packing are used to reduce engine noise, then noise attenuation is improved, but back pressure and resistance to free discharge of combustion gases increase
Solution Approach 1:
The patent extracts the noise attenuation function from complex baffle systems and packing materials, achieving sound wave attenuation through the geometric configuration of the elongated horizontal fluid passage and the arrangement of sound chambers at opposite ends. This extraction eliminates the need for restrictive baffles and packing, allowing free gas discharge while maintaining noise attenuation through the acoustic path length and chamber reflections.
Solution Approach 2:
The patent replaces mechanical noise reduction methods (baffles and packing that physically obstruct flow) with an acoustic field-based approach. The horizontal elongated passage and strategically positioned sound chambers create acoustic path length and reflections that attenuate sound waves without mechanically restricting gas flow. This substitution eliminates back pressure while maintaining effective noise attenuation.
4Weight of moving object
If the muffler is made lightweight for automotive applications, then ease of installation and vehicle weight are improved, but manufacturing precision and complexity increase
Solution Approach 1:
The patent merges the structural housing and internal sound attenuation features into a single integrated component. The elongated horizontal fluid passage and sound chambers are formed as integral parts of the muffler body rather than separate assemblies requiring precise alignment. This merging simplifies manufacturing by reducing the number of parts and assembly steps while maintaining the lightweight design, thereby reducing manufacturing precision requirements.
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 achieves effective sound attenuation across a broader frequency range in a more compact and lightweight form, suitable for various vehicle applications while reducing manufacturing complexity and size constraints.
Implementation Method 1
a sound wave front travels at rapid sonic velocities through the exhaust system
Implementation Method 2
When the sound wave front exits the exhaust system, it continues to pass through the air until three dimensional diffusion causes it to eventually dissipate. As the wave front passes an object, an overpressure is created at the surface of the object
Implementation Method 3
it continues to pass through the air until three dimensional diffusion causes it to eventually dissipate
Implementation Method 4
efforts have been underway to reduce or muffle the noise caused by the engine
Implementation Method 5
a sound wave front travels at rapid sonic velocities through the exhaust system. This wave front is the boundary between the high pressure exhaust pulse and ambient pressure
Data Source
AI summary
A muffler for reducing the sounds of combustion gases exhausted from an internal combustion engine. The muffler including an elongated fluid passage extending between an inlet and an outlet such that the outlet is in fluid communication with the inlet. The inlet of the muffler being connectable with the gases exhausted from the engine and the outlet being connectable with the atmosphere. The passage having a first side region and a second side region circumferentially spaced from the first region with a fluid passage in at least one of the first and second side regions. The muffler further including a side attenuation sound chamber adjacent the at least one of the side regions wherein the chamber is circumferentially spaced from the other of the at least one side region.