Muffler Perforation Geometry for Lower Exhaust Turbulence

Solution Overview

Problem

Existing mufflers for internal combustion engines face challenges in achieving both effective flow guidance and noise reduction, particularly due to turbulence at through-flow openings in exhaust gas conduit pipes and partition walls.

Innovation Solution

The muffler components feature through-flow openings with a decreasing flow cross section and rounded, edge-free transitions, guided by extensions that project beyond the downstream side of the wall, reducing turbulence and noise generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If through-flow openings with constant cross section are used in muffler components, then manufacturing is simple, but turbulence occurs and flow resistance increases

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidturbulence and flow resistance

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by transitioning the through-flow opening cross-section from constant to variable, specifically decreasing in the flow direction. This geometric parameter modification reduces turbulence and flow resistance while maintaining manufacturing feasibility through standard forming processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs curvature by rounding the edges and transitions of the through-flow openings, eliminating sharp corners. This spherical/curved geometry reduces flow separation and turbulence, improving flow characteristics without significantly complicating the manufacturing process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If sharp-edged through-flow openings are used, then manufacturing is easier, but noise generation increases due to turbulence

Engineering Contradiction:

Improveopening formation simplicityVSAvoidnoise generation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies curvature by rounding the edges and transitions of the through-flow openings, eliminating sharp corners. This spherical/curved geometry reduces flow separation and turbulence, improving flow characteristics without significantly complicating the manufacturing process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent applies parameter changes by transitioning the through-flow opening cross-section from constant to variable, specifically decreasing in the flow direction. This geometric parameter modification reduces turbulence and flow resistance while maintaining manufacturing feasibility through standard forming processes.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If through-flow openings with abrupt cross-section changes are used, then device complexity is reduced, but flow guidance is poor and turbulence increases

Engineering Contradiction:

Improveopening geometry simplicityVSAvoidflow guidance quality

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by transitioning the through-flow opening cross-section from constant to variable, specifically decreasing in the flow direction. This geometric parameter modification reduces turbulence and flow resistance while maintaining manufacturing feasibility through standard forming processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs curvature by rounding the edges and transitions of the through-flow openings, eliminating sharp corners. This spherical/curved geometry reduces flow separation and turbulence, improving flow characteristics without significantly complicating the manufacturing process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 flow guidance and reduces noise by minimizing turbulence and flow resistance through the muffler components, improving overall muffling performance.

Implementation Method 1

the through-flow opening flow cross section decreases in the flow direction in order to provide a through-flow opening flow-guiding surface. As a result of the provision of flow-guiding surfaces at through-flow openings in components of mufflers which decrease in their flow cross section in the flow direction, the exhaust gas expelled by an internal combustion engine is guided out of the region of larger flow cross section into the region of smaller flow cross section of a respective through-flow opening. Turbulence which occurs in the exhaust gas flow in the region of the through-flow openings is thereby reduced

Methodology Applied

Scientific EffectTurbulence reduction through flow-guiding surface: Flow Separation

Data Source

PatentUS12467392B2Muffler, exhaust system including a muffler, and method of making a muffler for an exhaust system

Publication Date: 2025.11.11 PUREM GMBH

AI summary

A muffler for an exhaust system of an internal combustion engine includes at least one muffler component with a perforation defined by a plurality of through-flow openings in a wall of the muffler component. The through-flow openings can be flowed through in a flow direction in the direction from an upstream side of the wall to a downstream side of the wall. At least in the case of some or all of the through-flow openings of the perforation, a through-flow opening flow cross section decreases in the flow direction in order to provide a through-flow opening flow-guiding surface.