Exhaust Heating Device Labyrinth Insulation

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Solution Overview

Problem

Existing heating devices for exhaust systems of internal combustion engines face inefficiencies due to heat loss from the combustion chamber, leading to overheating of components and reduced energy efficiency, as they struggle to quickly reach the high operating temperature required for catalysts during cold starts, resulting in high polluting emissions.

Innovation Solution

A heating device with a tubular body and labyrinthine structure that provides thermal insulation and pre-heats combustion air, optimizing air-fuel mixing and using a static mixer to enhance turbulence, while controlling the temperature of combustion gases through calibrated exchange holes to efficiently heat the catalyst without overheating nearby components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If thermal insulation is applied to the combustion chamber walls to limit heat dispersion, then heat loss is reduced and energy efficiency is improved, but the production cost and device size significantly increase

Engineering Contradiction:
Improveheat loss from combustion chamberVSAvoidproduction cost and device size
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The combustion chamber walls serve dual functions: they contain the combustion process and simultaneously preheat the incoming air through controlled heat transfer. The walls act as a heat exchanger, absorbing heat from combustion gases and transferring it to the air stream, thereby reducing overall heat loss without requiring external insulation layers

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent modifies the thermal properties of the combustion chamber system by changing the temperature parameters of different zones. The walls maintain different temperatures on their inner and outer surfaces, creating a controlled thermal gradient that optimizes heat transfer to the air while limiting heat loss to the surroundings, eliminating the need for additional insulation

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the combustion chamber walls are allowed to release heat to surrounding components, then manufacturing simplicity is maintained, but nearby components overheat and energy efficiency decreases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidoverheating of nearby components
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The incoming air stream acts as an intermediary heat transfer medium. It absorbs excess heat from the combustion chamber walls in a controlled manner, preventing direct heat transfer to surrounding components. This intermediary layer protects nearby parts from overheating while utilizing the thermal energy that would otherwise be wasted

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful effect of heat release from the combustion chamber walls into a beneficial preheating process. The heat that would otherwise overheat surrounding components is instead used to preheat the incoming air, improving combustion efficiency and reducing the need for external heating systems

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 achieves high energy efficiency, reduces component overheating, and maintains thermal power while being compact and inexpensive to manufacture, ensuring effective catalyst heating and reduced emissions during cold starts.

Implementation Method 1

by burning fuel, generates a flow of (very) hot air passing through the catalyst

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

generates a flow of air that passes through the combustion chamber

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

A heating device with a tubular body and labyrinthine structure that provides thermal insulation

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Implementation Method 4

using a static mixer to enhance turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 5

controlling the temperature of combustion gases through calibrated exchange holes to efficiently heat the catalyst

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Data Source

PatentEP3974626B1Heating device for an exhaust system of an internal combustion engine
Publication Date: 2023.12.13 MARELLI EURO SPA
  • EP3974626B1 patent drawingFigure 1
  • EP3974626B1 patent drawingFigure 2
  • EP3974626B1 patent drawingFigure 3

AI summary

A heating device (6) for an exhaust system (1) of an internal combustion engine (2); the heating device (6) has: a first tubular body (12) wherein a combustion chamber (7) is obtained; a fuel injector (9) to inject fuel into the combustion chamber (7); an inlet opening (18), which is obtained through the first tubular body (12) and can be connected to a fan (8) to receive an air flow, which is directed into the combustion chamber (7); a hot air outlet opening (17) to let hot air out of the combustion chamber (7); an outlet duct (11), which originates from the outlet opening (17); a spark plug (10) which is mounted through a side wall (16) of the first tubular body (12) to trigger the combustion of a mixture of air and fuel; and a labyrinth (26), which surrounds a side wall (16) of the tubular body (12), starts from the inlet opening (18), ends in the combustion chamber (7), and the air must necessarily flow out of the inlet opening (18) until reaching the combustion chamber (7) .