Truck Differential Fairing for Aerodynamic Drag Reduction

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Solution Overview

Problem

Current designs for reducing aerodynamic drag on truck differentials and related components are costly, weigh additional components, complicate repair, and do not effectively minimize airflow impacts on fuel economy.

Innovation Solution

A fairing system is attached to the truck frame, positioned forward of the drive axle and differential, deflecting airflow using a combination of rigid and compliant materials to minimize drag while allowing for easy maintenance and repair, with a cut-out for the drive shaft and adjustable positions to optimize airflow redirection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional fairings are added to control airflow under the truck, then aerodynamic drag is reduced, but vehicle weight increases and repair complexity increases

Engineering Contradiction:
Improveaerodynamic dragVSAvoidrepair complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The fairing is divided into a rigid portion and a compliant portion, allowing each segment to serve its specific function while simplifying overall installation and repair. The rigid portion provides structural support and primary airflow deflection, while the compliant portion adapts to vibrations and minor misalignments without requiring complex adjustment mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fairing incorporates a compliant portion made of flexible material that can dynamically change its physical state in response to vibrations and airflow conditions. This compliance allows the fairing to maintain effectiveness across varying operating conditions without requiring complex active control systems or frequent adjustments.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If traditional fairings are added to control airflow under the truck, then aerodynamic drag is reduced, but vehicle weight increases

Engineering Contradiction:
Improveaerodynamic dragVSAvoidvehicle weight
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

The fairing uses a compliant portion constructed from flexible material that acts as a thin, adaptive shell for airflow control. This flexible shell approach provides effective aerodynamic management while minimizing the weight penalty compared to rigid, bulky fairing structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The fairing combines rigid and compliant materials in a single structure, creating a composite component that leverages the strengths of each material type. The rigid portion provides structural integrity while the compliant portion adds minimal weight but delivers significant aerodynamic benefit through its flexibility.

Inventive Principle:
Principle #40Composite materials

3Use of energy by moving object

If complex fairing designs are used to minimize airflow impacts, then fuel economy improves, but manufacturing cost and design complexity increase

Engineering Contradiction:
Improvefuel economyVSAvoiddesign complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The fairing is segmented into rigid and compliant portions that can be manufactured separately using different processes and then assembled. This segmentation simplifies manufacturing by allowing each portion to be optimized independently, reducing overall design complexity while maintaining fuel economy benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compliant portion's ability to change its physical parameters in response to environmental conditions eliminates the need for complex active control systems. This passive adaptation simplifies the overall design while achieving the desired aerodynamic performance for improved fuel economy.

Inventive Principle:
Principle #35Parameter changes

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 fairing system effectively reduces aerodynamic drag on truck components, enhances fuel economy, and simplifies maintenance by being removable and adaptable to different driving conditions, maintaining structural integrity and minimizing weight and design complexity.

Implementation Method 1

Fairings, deflectors, foils, sloping hoods, rolled-under bumpers, recessed door handles can add design costs and weight, and complicate vehicle repair and servicing. Nevertheless, the designers' goal is to offset these negative effects with an overall reduction of the drag coefficient such that vehicle fuel economy can increase.

Methodology Applied
Scientific EffectAerodynamic drag reduction: Drag

Implementation Method 2

A truck can include a fairing for directing air flow around the differential. The fairing can be attached to the frame forward of the at the least one drive axle and forward of the at least one differential.

Methodology Applied
Scientific EffectAirflow deflection: Flow Separation

Data Source

PatentEP2802468B1Truck fairing
Publication Date: 2019.04.17 VOLVO GROUP NORTH AMERICA LLC
  • EP2802468B1 patent drawingFigure 1
  • EP2802468B1 patent drawingFigure 2
  • EP2802468B1 patent drawingFigure 3

AI summary

A truck includes a frame, an operator cab on the frame and a drive axle having a differential. The differential can be connected to a drive shaft. A fairing for directing air flow around the differential is attached to the frame forward of the drive axle and forward of the differential. The fairing can have a non-deflected position and a deflected position.