Silencer Sensor Port Structure for Easier Exhaust Pipe Assembly

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Solution Overview

Problem

Existing silencers for combustion engines face assembly challenges due to the radial penetration of exhaust gas sensors, leading to potential assembly errors and complications.

Innovation Solution

A silencer design with an external shell member and internal pipe featuring a cylindrical projection, a cap, and a distinct cap component that simplifies assembly by allowing the internal pipe to be inserted axially without interference, and includes a cap to prevent exhaust leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the exhaust gas sensor radially penetrates through both the casing and the pipe member, then the sensor can be positioned to sense exhaust gas, but assembly errors occur and assembly steps become complicated

Engineering Contradiction:
Improveexhaust gas sensing capabilityVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention divides the assembly into distinct segments: the internal pipe with its projection, the cap as a separate component, and the external shell member. The cap is joined to both the projection and the external shell member, creating modular assembly units that can be assembled independently, thereby reducing overall assembly complexity while maintaining sensor positioning accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap serves as an intermediary component between the internal pipe and the external shell member. It mediates the connection by joining to both the projection on the internal pipe and the external shell member, compensating for assembly errors and preventing exhaust leakage without requiring direct alignment between the pipe and shell member.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the internal pipe is inserted axially into the external shell member without a projection, then assembly is simpler, but subsequent formation of projection is required which complicates the process

Engineering Contradiction:
Improveinsertion easeVSAvoidassembly efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The projection is formed on the internal pipe before insertion into the external shell member. This preliminary action allows the pipe to be inserted axially in a single straightforward operation, eliminating the need for subsequent projection formation steps and improving overall assembly efficiency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4671510A1silencer
Publication Date: 2025.12.31 KAWASAKI MOTORS LTD
  • EP4671510A1 patent drawingFigure 1
  • EP4671510A1 patent drawingFigure 2
  • EP4671510A1 patent drawingFigure 3

AI summary

A silencer 20 includes an external shell member 31 having a silencer chamber SP defined therein and an internal pipe 51 disposed in the silencer chamber SP. The external shell member 31 has an external shell opening 60 formed in a peripheral wall thereof, and the internal pipe 51 has a pipe opening 68 is formed in a peripheral wall thereof. The internal pipe 51 includes a cylindrical projection 69 protruding radially outwards from the peripheral wall of the internal pipe 51. The projection 69 is provided along the circumference of the pipe opening 68 about the axis of the pipe opening 68. An oxygen sensor 64 is positioned so as to plug the pipe opening 68. The silencer 20 includes a cap 72 that covers the external shell opening 66. The cap 72 is joined to a portion of the external shell member 31 around the external shell opening 66 and to the projection 69 of the internal pipe 51. An outer radius dimension d1 of the projection 69 is set smaller than an inner radius dimension d2 of the external shell member 31.