Flexible Rigid Aerodynamic Diffuser for Vehicle Underbody

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Solution Overview

Problem

Conventional aerodynamic diffusers with longitudinal fins under vehicles are prone to breakage or damage when encountering uneven ground or reliefs, limiting their ability to cover a maximum surface area and provide stability, especially at high speeds.

Innovation Solution

An aerodynamic diffuser with a combination of flexible and rigid fins, where flexible fins in the intermediate zone and rigid fins at the rear allow for maximum surface coverage and stability, using thermoplastic elastomer for flexible fins and a specific L-shaped cross-section with rivet fixation, enabling deformation without breakage and maintaining air pressure resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If long rigid fins are used to extend the diffuser surface area for maximum efficiency, then the aerodynamic performance is improved, but the risk of breakage or damage when encountering uneven ground increases

Engineering Contradiction:
Improvediffuser surface areaVSAvoidresistance to breakage
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the properties of fins in different zones: the first series of fins in the intermediate zone are made flexible to adapt to ground reliefs, while the second series of fins in the rear zone are rigid to maintain structural integrity and aerodynamic efficiency. This localized differentiation resolves the contradiction by allowing each zone to have the appropriate mechanical properties for its specific functional requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The diffuser is segmented into two distinct series of fins with different mechanical properties. The first series comprises flexible fins in the intermediate zone, and the second series comprises rigid fins in the rear zone. This segmentation allows the system to simultaneously achieve large surface area coverage and resistance to breakage by distributing different functional requirements to different segments.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the diffuser covers maximum surface area under the vehicle for optimal efficiency, then aerodynamic performance is improved, but the ground clearance requirement increases

Engineering Contradiction:
Improvediffuser surface areaVSAvoidground clearance
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent employs dynamics by making the first series of fins flexible rather than rigid. This flexibility allows the fins to dynamically adapt to ground reliefs and variations in ground clearance, enabling the diffuser to maintain maximum surface area coverage without requiring increased ground clearance. The flexible fins can deform to accommodate the space constraints while preserving the aerodynamic function.

Inventive Principle:
Principle #15Dynamics

3Strength

If rigid fins are used throughout the diffuser, then structural strength is improved, but the ability to adapt to uneven ground surfaces is reduced

Engineering Contradiction:
Improvestructural strengthVSAvoidadaptability to ground reliefs
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by assigning different mechanical properties to different zones of the diffuser. The first series of fins in the intermediate zone are made flexible to provide adaptability to ground reliefs, while the second series of fins in the rear zone are made rigid to provide structural strength. This localized differentiation resolves the contradiction by allowing each zone to have the appropriate mechanical properties for its specific functional requirements.

Inventive Principle:
Principle #3Local quality

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 diffuser achieves optimal efficiency and stability on varied ground surfaces while maintaining low ground clearance, with flexible fins absorbing bumps and rigid fins providing structural support, enhancing vehicle grip and stability at high speeds.

Implementation Method 1

at least part of the fins being flexible... the fins of the first series are made of thermoplastic elastomer... flexible fins absorbing bumps

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

maintaining air pressure resistance... the drifts of the first series and / or the second series are fixed to the base by rivet

Methodology Applied
Scientific EffectAerodynamic pressure: Pressure Increase

Data Source

PatentEP3548364B1Aerodynamic diffuser for underbody of a motor vehicle
Publication Date: 2021.01.06 RENAULT SA
  • EP3548364B1 patent drawingFigure 1~3

AI summary

The invention relates to an aerodynamic diffuser (3) for the underbody (2) of a motor vehicle, comprising a series of fins (4) extending essentially in the longitudinal direction (X) of the vehicle, characterised in that at least some of the fins (4) are supple.