Asymmetrical Diffuser Rear Tub for Motorhome Stability

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Solution Overview

Problem

Touring or leisure vehicles pose handling challenges due to their dimensions and weight, requiring special driving skills and posing safety risks on the road.

Innovation Solution

The integration of asymmetrical diffusers under the vehicle, designed as a rear tub with recesses and stiffening elements, creates a negative pressure effect improving aerodynamics and stability, enhancing driving behavior and safety by generating downforce.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate diffuser component is added to improve handling, then aerodynamic performance improves, but device complexity increases

Engineering Contradiction:
Improvehandling stabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The diffuser is integrated into the rear tub structure, combining two previously separate components (diffuser and rear tub) into a single unified structure. This eliminates the need for separate mounting and reduces overall complexity while maintaining the aerodynamic benefits of the diffuser and the structural/storage benefits of the rear tub

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rear tub structure is designed to serve multiple functions: it provides structural support for the vehicle rear end, creates storage volume through its hollow construction, and generates aerodynamic downforce through integrated diffuser elements. This multi-functionality reduces the need for additional separate components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the diffuser is designed with asymmetrical shape to improve pressure distribution, then aerodynamic efficiency improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidshape accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The asymmetrical diffuser profile is integrated directly into the rear tub forming process, allowing the complex asymmetrical geometry to be created in a single manufacturing operation rather than requiring separate precision machining or assembly of multiple parts

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The diffuser geometry is optimized by varying parameters such as angle of attack, expansion angle, and profile curvature across different sections. The asymmetrical design creates specific pressure distributions that generate downforce while the integrated construction allows these parameter variations to be achieved through standard manufacturing tolerances

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If stiffening elements are added to the rear tub, then structural stability improves, but device complexity increases

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

Solution Approach 1:

Stiffening ribs are strategically positioned at specific locations within the rear tub structure where maximum structural benefit is achieved. Rather than uniformly reinforcing the entire structure, ribs are placed at critical stress points and load paths, providing enhanced stability with minimal additional complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The stiffening ribs are integrated into the rear tub manufacturing process as integral structural features rather than separate attachments. This combining of structural reinforcement elements with the main body structure eliminates additional assembly steps and reduces overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

4Volume of stationary object

If multiple recesses are created in the rear tub, then storage volume increases, but manufacturing complexity increases

Engineering Contradiction:
Improvestorage spaceVSAvoidstructural features
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

Multiple storage recesses are formed as integral features of the rear tub during the primary manufacturing process, such as injection molding or stamping. This allows complex multi-chamber storage geometries to be created in a single operation without requiring separate assembly steps for each recess

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rear tub is divided into multiple separate storage compartments through recesses and internal partitions. This segmentation creates organized storage spaces for different items while the integrated construction method keeps manufacturing complexity manageable by forming all compartments simultaneously

Inventive Principle:
Principle #1Segmentation

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 solution simplifies manufacturing, increases storage space, and significantly improves handling and safety by enhancing the vehicle's stability and aerodynamics, while also providing a sacrificial layer for damage protection.

Implementation Method 1

Diffusers can be understood as active surfaces in the underbody area of a touring or leisure vehicle to improve aerodynamics through a suction effect, i.e. the formation of a negative pressure

Methodology Applied
Scientific EffectNegative pressure generation: Bernoulli Effect

Implementation Method 2

to improve aerodynamics through a suction effect, i.e. the formation of a negative pressure

Methodology Applied
Scientific EffectAerodynamic suction: Suction

Implementation Method 3

Air flows under the vehicle from both sides and forms vortices in pairs, which flow through the diffuser in opposite directions

Methodology Applied
Scientific EffectVortex formation: Vortex Ring

Data Source

PatentEP3549847B1Journey and recreational vehicle
Publication Date: 2023.05.24 HYMER GMBH & CO KG
  • EP3549847B1 patent drawingFigure 1~2

AI summary

A travel or leisure vehicle (1), in particular a motorhome, caravan or the like, is proposed, comprising a front section (2) and a rear section (3), wherein the travel or leisure vehicle (1) includes at least one diffuser (4), the at least one diffuser (4) being arranged in an underbody section (5) of the travel or leisure vehicle (1) for generating negative pressure. (Fig. 1)