Modular Engine Muffler Partitioning for Airtight Welding
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Solution Overview
Problem
Existing muffler designs for small-sized general-purpose engines face challenges in optimizing exhaust pipe length and expansion chamber capacity for efficient catalyst purification and muffling performance, requiring flexible dimensioning and enhanced airtightness to meet varying exhaust characteristics.
Innovation Solution
A cylindrical muffler body with partition plates that allow for adjustable expansion chamber lengths and capacities through modular design, where divided muffler body members are welded to an annular section, enabling easy adjustment and high-quality welding for improved airtightness and muffler performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the muffler body is constructed as a single integrated piece, then manufacturing simplicity is maintained, but dimensioning design freedom is limited
Solution Approach 1:
The muffler body is divided into multiple separate body members (first body member, second body member, etc.) that can be independently manufactured and then assembled together. This segmentation allows each component to be optimized separately while providing flexibility in adjusting the overall dimensions and expansion chamber capacities to match different exhaust characteristics.
2Reliability
If partition plates are fixed using traditional methods (caulking, brazing, screwing), then assembly is achieved, but airtightness and welding quality are compromised
Solution Approach 1:
The partition plate fixation method is merged with the body member assembly process. The partition plates are positioned between the body members during welding, and all components are joined simultaneously through welding from the radially outward direction, creating a unified airtight structure that eliminates separate fixation steps.
3Reliability
If welding is performed from the radially outward direction along entire perimeters, then airtightness is enhanced, but manufacturing complexity increases
Solution Approach 1:
The partition plates are preliminarily positioned and fixed between the body members before the welding process begins. This preliminary positioning ensures that the partition plates are correctly located to maintain airtightness, and the subsequent welding process simply needs to join the components along their perimeters from the radially outward direction.
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 enhances dimensioning flexibility, ensures optimal muffler performance by adjusting chamber lengths and capacities, and achieves high airtightness, thereby securing the quality of the muffler while accommodating different exhaust characteristics.
Implementation Method 1
The opposed end portions of the plurality of divided muffler body members are welded, from a radially outward direction of the muffler body, to the outer peripheral surface of the annular section along respective entire perimeters thereof
Data Source
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AI summary
An engine muffler (10; 10A; 10B) includes a cylindrical muffler body (20) partitioned by at least one partition plate (30, 40) in a longitudinal direction into a plurality of expansion chambers (91 - 93). The muffler body is constructed of a plurality of divided muffler body members (21 - 23) divided from each other in the longitudinal direction at the position of the partition plate, and a gap (Cr1, Cr2) is provided between opposed end portions (21a, 22a, 22c, 23a) of the body members. The partition plate has an annular section (31, 41) held in fitting engagement with the inner peripheral surface of at least one of the opposed end portions, and it is positioned in such a manner as to close the gap. The opposed end portions are welded, from a radially outward direction, to the outer peripheral surface of the annular section along their respective entire perimeters.