Generator Exhaust Sound Reduction via Vertical Port Separation
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Solution Overview
Problem
Existing engine-driven working machines face challenges in effectively insulating and reducing exhaust sound due to the lateral orientation of the exhaust port, which leads to inadequate noise reduction.
Innovation Solution
The engine-driven working machine design includes a tail pipe positioned at the lower portion of the muffler with a discharge port above it, a baffle plate to guide cooling air below the muffler, and a protector covering the muffler and tail pipe with a sound absorbing member on its inner surface, enhancing sound insulation and reducing noise by separating the exhaust port from the discharge port and directing cooling air to prevent heat deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the exhaust port is opened to be laterally oriented to face the discharge port, then the structure is simple, but the exhaust sound insulation is insufficient
Solution Approach 1:
The exhaust port is reoriented from a lateral opening facing the discharge port to a downward opening at the lower portion of the muffler. This dimensional change in orientation allows exhaust gas to be discharged downward while the discharge port remains on the outer case, creating spatial separation that insulates exhaust sound from the discharge port area.
2Volume of moving object
If the discharge port is positioned close to the exhaust port, then the structure is compact, but the exhaust sound insulation is poor
Solution Approach 1:
The exhaust port is positioned at the lower portion of the muffler with downward orientation, while the discharge port is positioned on the outer case above the tail pipe. This vertical dimensional separation creates sufficient distance between the exhaust gas discharge location and the discharge port, effectively insulating exhaust sound while maintaining compact horizontal footprint.
3Device complexity
If cooling air is not guided to the tail pipe area, then the structure is simple, but the components around the tail pipe deteriorate due to exhaust heat
Solution Approach 1:
A baffle plate is introduced as an intermediary component to guide cooling air from the cooling fan toward the lower portion of the muffler and tail pipe area. This simple plate structure redirects the flow of cooling air to pass through or around the exhaust system components, providing thermal protection without requiring complex cooling channels or modifications.
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 configuration effectively reduces exhaust sound by improving sound insulation and preventing heat damage to components, resulting in a more favorable noise reduction and enhanced durability of the sound absorbing materials.
Implementation Method 1
a sound absorbing member that is provided on an inner surface of the protector... the exhaust sound that is discharged from the discharge port can be absorbed by the sound absorbing member
Implementation Method 2
the baffle plate is disposed to face the discharge port, and cooling air is guided to below the muffler with the baffle plate... the cooling air can be guided to the tail pipe and surroundings of the tail pipe
Data Source
AI summary
An engine-driven working machine capable of favorably reducing exhaust sound (that is, noise) is provided. An engine-driven working machine 10 is a generator in which an engine 15 and a muffler 67 are housed in an inside 13 of an outer case 12. The generator 10 includes a tail pipe 68 that is provided at a lower portion 67a of the muffler 67, a discharge port 37 that is disposed above the tail pipe 68, and a baffle plate 84 that is disposed to face the discharge port 37. The discharge port 37 is formed in the outer case 12. Further, cooling air that is sent from a cooling fan 17 is guided to below the muffler 67 with the baffle plate 84.