Flow-Directing Element Layout for Uniform Burner Air Cooling

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Solution Overview

Problem

Existing flow guide elements for heating devices, particularly those with evaporator burners in vehicles, face challenges such as limited evaporator receptacle size due to bowl-shaped geometries, difficulty in centered and secure fixation, material limitations due to proximity to hot parts, and uneven air guidance leading to non-uniform cooling, especially with eccentric fans.

Innovation Solution

A flow guide element with a laterally arranged inflow region and a centrally arranged outflow region, featuring guide elements that facilitate airflow from the inflow to the outflow region, is designed to be self-centering and adaptable to the shape of the receiving heating device. This element is preferably made of molded plastic or metallic materials and includes recesses for a glow plug and fastening elements, allowing for easy assembly and secure fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a bowl-shaped combustion air guide element is used, then the evaporator receptacle size is limited, but the air flow guidance is simplified

Engineering Contradiction:
Improveevaporator receptacle sizeVSAvoidflow guidance structure
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The flow guide element is divided into functionally independent regions: an inflow region with laterally arranged openings for air intake, a guide region with flow guide elements directing air flow, and a centrally arranged outflow region. This segmentation allows each region to be optimized independently, enabling larger evaporator receptacles while maintaining effective air flow guidance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a traditional bowl-shaped single-region structure to a multi-region planar structure with distinct inflow, guide, and outflow regions arranged in specific spatial relationships. This dimensional reorganization allows air to be guided from lateral inflow openings through the guide region to a central outflow region, achieving both larger receptacle space and effective flow control.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a fan pre-chamber with eccentric fan is used, then the air guidance becomes uneven, but the assembly is simplified

Engineering Contradiction:
Improveassembly simplicityVSAvoidair flow uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The flow guide element incorporates locally adapted flow guide elements within the guide region that are specifically designed to compensate for the eccentric fan position. These local flow guidance structures create uniform air distribution despite the asymmetric air intake, achieving precise flow control in the critical outflow region while maintaining simple overall assembly.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The guide region with its flow guide elements acts as an intermediary between the lateral inflow region and the central outflow region. This intermediate structure processes the asymmetric air flow from the eccentric fan, redistributing it uniformly before delivery to the combustion chamber, thus mediating between simple assembly and precise flow uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If the flow guide element is made close to hot burner parts, then the cooling efficiency is improved, but the material selection is limited

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmaterial selection
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The flow guide element is constructed from composite materials or high-temperature resistant materials that combine thermal stability with ease of manufacturing. This allows the element to be positioned close to hot burner parts for effective cooling while maintaining material versatility and resistance to thermal degradation.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If the flow guide element is self-centering, then the assembly effort is reduced, but the structural complexity increases

Engineering Contradiction:
Improveassembly effortVSAvoidself-centering mechanism
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The flow guide element incorporates self-centering features that automatically align and position the component during assembly without requiring external centering tools or complex adjustment mechanisms. The element's own geometry and mounting features enable it to center itself relative to the combustion chamber, reducing assembly effort while the self-centering capability is integrated into the basic structure rather than added as separate 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

The proposed flow guide element effectively guides airflow from an eccentric fan to the central outflow area in a simple and cost-effective manner, achieving uniform cooling and improving the overall efficiency and assembly of the heating device.

Implementation Method 1

at least one guide element which is arranged in such a way that it enables flow guidance from the inflow region to the outflow region

Methodology Applied
Scientific EffectFluid flow guidance:

Implementation Method 2

A combustion air pre-chamber 20 is formed in a ring around the combustion chamber 8. A gap 18 between the bottom wall 26 and the evaporator receptacle 10 opens into the combustion air pre-chamber 20

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 3

a second flow path 46 is provided within the heat exchanger 6, through which the cooling fluid of the motor vehicle is guided. The first 42 and the second 46 flow paths are arranged such that, during use, heat is effectively transferred from the exhaust gases to the cooling fluid

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP4081738B1Flow-directing element, flow-directing system and heating apparatus
Publication Date: 2025.06.18 WEBASTO AG
  • EP4081738B1 patent drawingFigure 1
  • EP4081738B1 patent drawingFigure 2
  • EP4081738B1 patent drawingFigure 3

AI summary

The invention relates to a flow-directing element (100) for a heating apparatus (2), in particular a heating apparatus (2) with an evaporator burner (4), having a body which comprises a laterally arranged inflow region (102) on an underside of the flow-directing element, having a centrally arranged outflow region (104), which comprises a through-passage from an underside of the flow-directing element to an upper side of the flow-directing element, the upper side being located opposite the underside, and having at least one guide element (16), which is arranged such that it allows flow to be guided from the inflow region to the outflow region. The invention also relates to a flow-directing system and to a heating apparatus.