Active Muffler Connecting Pipe Thermal Management

Solution Overview

Problem

The existing exhaust systems for internal combustion engines face challenges in reducing the thermal load on active silencers and their electronics due to hot exhaust gases, which can lead to overheating and damage.

Innovation Solution

Incorporating internal cooling fins and a separate cooler section with external cooling ribs in the connecting pipe between the muffler housing and the exhaust pipe, which increases thermal mass and enhances heat dissipation, while maintaining acoustic coupling for noise propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the connecting pipe is used to acoustically couple the silencer housing to the exhaust pipe, then sound propagation is enabled, but thermal load from exhaust gases damages the silencer and electronics

Engineering Contradiction:

Improvesilencer and electronics protectionVSAvoidthermal load

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The connecting pipe is divided into a hot section and a cool section, with the electro-acoustic transducer housed in the cool section away from direct exhaust gas exposure. This segmentation allows the system to maintain acoustic coupling while protecting sensitive components from thermal damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connecting pipe acts as an intermediary element between the exhaust pipe and silencer housing, providing both acoustic coupling and thermal isolation. The pipe's structure mediates between the hot exhaust gases and the temperature-sensitive electronics, allowing sound transmission while blocking direct heat transfer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If cooling sections with external cooling ribs are added to the connecting pipe, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:

Improveheat dissipationVSAvoidconnecting pipe structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

External cooling ribs are added to the connecting pipe's outer surface, extending the heat dissipation surface into the radial dimension. This allows increased heat transfer area without significantly increasing the pipe's longitudinal length or internal volume, maintaining compactness while improving cooling.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cooling ribs utilize ambient air and natural convection currents to dissipate heat from the connecting pipe. The structure serves its own cooling function without requiring external active cooling systems, pumps, or additional energy input, thereby improving heat dissipation while avoiding excessive complexity.

Inventive Principle:

Principle #25Self-service

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 effectively reduces the thermal load on the converter and electronics, allowing for a more upstream placement of the active muffler and improved heat management, thereby preventing overheating and extending the system's lifespan.

Implementation Method 1

Incorporating internal cooling fins and a separate cooler section with external cooling ribs in the connecting pipe between the muffler housing and the exhaust pipe, which increases thermal mass and enhances heat dissipation

Methodology Applied

Scientific EffectThermal mass: Heat Sink

Implementation Method 2

Incorporating internal cooling fins and a separate cooler section with external cooling ribs in the connecting pipe between the muffler housing and the exhaust pipe, which increases thermal mass and enhances heat dissipation

Methodology Applied

Scientific EffectHeat dissipation: Convection

Implementation Method 3

Incorporating internal cooling fins and a separate cooler section with external cooling ribs in the connecting pipe between the muffler housing and the exhaust pipe, which increases thermal mass and enhances heat dissipation

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 4

Incorporating internal cooling fins and a separate cooler section with external cooling ribs in the connecting pipe between the muffler housing and the exhaust pipe

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP2607638B1Exhaust system

Publication Date: 2023.05.17 PUREM GMBH

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Figure 5~13

AI summary

The present invention relates to an exhaust system (1) for an internal combustion engine, in particular of a motor vehicle, comprising at least one exhaust stream (2) having at least one exhaust pipe (3) carrying exhaust gas, and at least one active silencer (5) comprising a silencer housing (6) and at least one electroacoustic transducer (7) arranged in the silencer housing (6), as well as at least one connecting pipe (8) that fluidically connects the silencer housing (6) to the exhaust pipe (3). The thermal load on the transducer (7) can be reduced if a sound propagation path (9) designed for the propagation of airborne sound in the connecting pipe (8) is opaque to thermal radiation (16) emanating from the exhaust gas in the exhaust pipe (3).