Muffler Diffuser With Graduated Exhaust Holes
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Solution Overview
Problem
Conventional mufflers for portable work machines, such as engine blowers and chain saws, require a large space to accommodate exhaust caps, increasing the machine's size due to the need to diffuse and cool exhaust gases effectively, while maintaining low exhaust temperatures as per environmental regulations.
Innovation Solution
A muffler design featuring a diffuser with exhaust holes of varying sizes, where the opening rate increases towards the periphery, reducing internal pressure and allowing even diffusion and exhaust of gases without the need for additional space, and an inclined flange to secure the diffuser effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an exhaust cap is provided to change the flowing direction of exhaust gas and lengthen the distance between the exhaust outlet and exhaust opening, then the temperature of exhaust gas is lowered, but a large space is required which increases the size of the work machine
Solution Approach 1:
The exhaust gas flow is segmented into multiple paths through the plurality of exhaust holes distributed across the exhaust surface. This segmentation allows the exhaust gas to be divided and directed along different trajectories, effectively increasing the travel distance and cooling time without requiring a single large-volume exhaust cap structure.
Solution Approach 2:
The exhaust holes are arranged with different opening rates at different locations on the exhaust surface. The opening rate is set to be larger near the exhaust outlet and smaller toward the periphery, creating local variations in flow characteristics that optimize both temperature reduction and compact space utilization.
2Temperature
If the exhaust outlet is positioned toward the inner surface of the engine cover to lengthen the distance, then exhaust gas temperature is lowered, but the device complexity increases due to the need for exhaust cap and flow direction control
Solution Approach 1:
The diffuser is merged with the exhaust outlet structure, integrating the flow direction control function directly into the exhaust outlet assembly. This eliminates the need for separate exhaust caps and complex flow control mechanisms, reducing device complexity while maintaining effective exhaust gas temperature reduction.
Solution Approach 2:
The diffuser structure itself performs the flow direction control function through its geometric design. The inclined surface and opening rate distribution automatically guide the exhaust gas flow along the desired path without requiring additional active control components,实现ing self-service flow management.
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
This design effectively lowers exhaust gas temperature, reduces the machine's size by eliminating unnecessary space, and maintains engine performance by minimizing back-pressure and ensuring efficient gas diffusion.
Implementation Method 1
the exhaust gas is evenly diffused toward the outer peripheral side and evenly exhausted from the respective exhaust holes
Implementation Method 2
exhaust resistance (i.e. internal pressure) at the outer peripheral side is reduced in accordance with the setting of the opening rate provided by the exhaust holes formed on the exhaust surface
Data Source
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AI summary
A muffler 10 of a work machine in the form of an engine blower includes: a muffler body 11; and a diffuser 15 that covers an exhaust outlet 13 of exhaust gas provided on the muffler body 11. The diffuser 15 has a diffusion space to diffuse the exhaust gas and an exhaust surface 31 on which a plurality of exhaust circular holes 33 are provided to exhaust the exhaust gas to an outside. An opening ratio provided by the exhaust holes 33 of the exhaust surface 31 is gradually increased from a portion corresponding to the exhaust opening toward an outer periphery of the exhaust surface 31.