Thermally Insulated Exhaust Coupling with Composite Bellows

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Solution Overview

Problem

Existing thermally insulated coupling devices for exhaust pipes of endothermic engines are either expensive, bulky, difficult to manufacture, or compromise mechanical performance, leading to excessive heat transfer and reduced catalytic converter efficiency due to inefficient heat insulation.

Innovation Solution

A thermally insulated coupling device featuring a flexible metal bellows with annular undulations, a radially arranged flow guide liner, and a helically wound metal hose filled with thermally insulating material, such as glass fibre or ceramic fibre, which reduces heat dispersion and maintains mechanical performance by integrating the insulating material within the device's structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal bellows coupling device is used to connect exhaust pipes, then fluid-tight connection and vibration compensation are achieved, but heat transfer to the outside increases excessively

Engineering Contradiction:

Improvefluid-tight connection and vibration compensationVSAvoidheat transfer to outside

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

A thermally insulating material is introduced as an intermediary substance between the inner and outer metal bellows, filling the annular space to reduce heat transfer while maintaining the fluid-tight connection and vibration compensation functions of the metal bellows structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling device is transformed from a purely metal structure to a composite structure combining metal bellows with thermally insulating material, achieving both mechanical performance and thermal insulation requirements

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If thermally insulating material is added to the coupling device to reduce heat loss, then heat insulation improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveheat loss reductionVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The outer bellows is designed as a flexible metal shell that encloses the insulating material, creating a simple yet effective thermal barrier without requiring complex insulation structures or additional components

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The thermally insulating material is nested within the annular space between the inner and outer bellows, creating a compact layered structure where the insulating layer is contained within the metallic shell structure

Inventive Principle:

Principle #7Nested doll (Nesting)

3Loss of energy

If traditional heat insulation systems are implemented in the coupling device, then thermal insulation is achieved, but weight and manufacturing cost increase significantly

Engineering Contradiction:

Improveheat dispersion reductionVSAvoidcoupling device weight

Core Design Contradiction:

Loss of energyVSWeight of moving object

Solution Approach 1:

A porous thermally insulating material is used to fill the annular space between the bellows, providing effective thermal insulation with low density and minimal weight addition compared to solid insulation materials

Inventive Principle:

Principle #31Porous materials

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

The solution provides a compact, lightweight, cost-effective coupling device with enhanced vibration and noise damping, maintaining mechanical performance while significantly reducing heat dispersion and preserving catalytic converter efficiency.

Implementation Method 1

radial play present between the first flexible metal hose and respective radially external ridges of the undulations of the flexible metal bellows filled with a thermally insulating material

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

helically wound with its opposite lateral edges seamed together so as to form a hose

Methodology Applied

Scientific EffectSeaming: Welding

Implementation Method 3

compensating for positioning shifts/errors of the various exhaust pipe sections and/or reducing/eliminating vibrations transmitted from the engine to the exhaust system in general

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentEP3002493B1Thermally insulated coupling device for exhaust pipes of endothermic engines

Publication Date: 2017.08.16 FLEXIDER AUTOMOTIVE ITAL SRL

Figure 1~2
Figure 3~4

AI summary

A coupling device (1) designed to be arranged downstream of an exhaust manifold (4) of an endothermic engine, including an internal liner (9), for example defined by a section of rigid pipe (25), a metal bellow (5) having two opposite cylindrical ends (7 and 8) without undulations, external shielding provide by a flexible hose (10) made of a helical stripwound metal element (11), if necessary fitted with a seal (23) between respective interconnected edges (13 and 14) of a metal strip (12), which forms the flexible shielding hose, and an insulating material (17) resistant to high temperatures and arranged to completely fill a radial gap (16) provided between the external stripwound metal hose (10) and the bellow (5). The ends (19 and 20) of the shielding hose (10) are welded to two terminal elements (21b and 22b) fixed to the cylindrical ends (7 and 8) of the bellow and radially protruding therefrom.