Lightweight Acoustic Muffler Sandwich Panel Design

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Solution Overview

Problem

Mufflers for internal combustion engines face challenges in achieving lightweight construction while maintaining mechanical stability, as thin wall designs tend to excite vibrations and lead to noise and damage due to limited installation space in vehicles.

Innovation Solution

A muffler design incorporating a sandwich panel with a self-supporting support structure, including a tube arrangement that absorbs and transmits forces and bending moments, allowing for thin-walled construction without compromising stability, and utilizing a jacket hood to form a mechanically stable housing while keeping production costs low.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the wall thickness of the flat wall area is reduced to achieve lightweight construction, then the vehicle weight is reduced, but the mechanical stability decreases leading to vibrations and noise

Engineering Contradiction:
Improvemuffler weightVSAvoidmechanical stability
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The patent employs a sandwich panel construction consisting of multiple thin metal wall layers (typically 4-5 layers of approximately 0.1 mm each) separated by insulating material. This composite structure achieves the required mechanical stability and stiffness while maintaining low weight, resolving the contradiction between lightweight construction and mechanical stability. The sandwich structure provides high moment of inertia despite thin individual layers, preventing vibrations and noise.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If the wall thickness is reduced to save weight, then manufacturing cost is reduced, but the housing becomes susceptible to damage at attachment points

Engineering Contradiction:
Improvemuffler weightVSAvoiddamage resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The sandwich panel construction with multiple thin layers provides distributed strength throughout the structure, preventing stress concentration at attachment points. The insulating material between layers acts as a stress-distributing medium, enhancing reliability while maintaining thin overall wall thickness.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If a self-supporting support structure is added to maintain stability with thin walls, then mechanical stability is improved, but device complexity increases

Engineering Contradiction:
Improvemechanical stabilityVSAvoidstructural complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The support structure is integrated into the sandwich panel design itself, where the insulating material and metal layers work together as a unified load-bearing system. The tube arrangement is supported by the sandwich structure without requiring separate external bracing elements, thus maintaining mechanical stability while avoiding excessive complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Weight of moving object

If sandwich panels with multiple thin layers are used instead of conventional thick metal walls, then weight is significantly reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvemuffler weightVSAvoidmanufacturing ease
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The sandwich panel is manufactured by assembling discrete components (metal sheets and insulating material layers) in a systematic sequence. This segmentation allows for standardized production of individual layers that can be pre-fabricated and then assembled, reducing overall manufacturing complexity despite the multi-layer structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sandwich construction combines simple-to-manufacture materials (metal sheets and insulation) in an alternating layer pattern. Each layer can be produced using conventional processes, and the assembly follows straightforward joining procedures, making the composite structure economically viable despite its complexity.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2674585B1Lightweight acoustic muffler
Publication Date: 2016.09.07 EBERSPACHER EXHAUST TECH GMBH & CO
  • EP2674585B1 patent drawingFigure 1~2
  • EP2674585B1 patent drawingFigure 3~4
  • EP2674585B1 patent drawingFigure 5~7

AI summary

The invention relates to a silencer (1; 1') for an exhaust system of an internal combustion engine, in particular of a motor vehicle, - with a housing (2; 2') which has a housing shell (3; 3') extending in a circumferential direction (U) of the housing (2; 2'), - with at least one sandwich plate (6; 6') which forms a part of the housing shell (3; 3'), - with a housing interior (4) having at least one chamber (8) which is enclosed by the housing (2), - with a self-supporting support structure (5) which comprises a pipe arrangement (7) which is arranged at least partially in the housing interior (4).