Flexible Membrane Trailer Drag Reduction

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Solution Overview

Problem

Existing systems for reducing aerodynamic drag on trailers are limited in their ability to adjust to different operating conditions, such as varying speeds and cross-winds, due to fixed or inflexible rear profiles, which sub-optimally reduce fuel efficiency and increase transport costs.

Innovation Solution

A system featuring a flexible membrane actively deployable via a pressurized gas source and controller, allowing the membrane to change between pre-selected tapered aerodynamic shapes independent of vehicle speed, with optional telescoping actuators for enhanced stability and multiple profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a fixed or selectively deployable rigid panel is used at the rear of the vehicle, then the aerodynamic drag is reduced to some extent, but the system has limited capability to adjust to different operating conditions such as different speeds and cross-winds

Engineering Contradiction:

Improveaerodynamic dragVSAvoidadjustment to different operating conditions

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by replacing fixed or selectively deployable rigid panels with a flexible membrane that can dynamically adapt its shape and volume. The flexible membrane is inflatable and deflatable, allowing it to change its aerodynamic profile in response to varying operating conditions such as different speeds and cross-winds, thereby resolving the contradiction between drag reduction and adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by enabling the flexible membrane to vary its volume and shape parameters through inflation and deflation controlled by a controller. This allows the system to adjust the aerodynamic profile parameters (volume, shape, surface area) to optimize drag reduction under different operating conditions, transforming a static panel into a dynamically adjustable structure.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a flexible air bag is used at the rear of the vehicle, then the capability to adjust to different operating conditions is improved, but the shape of the bag is determined by air flow and pressure essentially fixed by the speed of the vehicle, limiting drag reduction effectiveness

Engineering Contradiction:

Improveadjustment to different operating conditionsVSAvoidaerodynamic drag

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies feedback by implementing a controller that receives input from a sensor detecting operating conditions (such as vehicle speed and cross-wind) and actively adjusts the inflation/deflation of the flexible membrane accordingly. This closed-loop feedback system ensures the membrane adopts the optimal aerodynamic shape for current conditions, resolving the issue where passive air bags are shape-constrained by fixed air flow and pressure.

Inventive Principle:

Principle #23Feedback

3Loss of energy

If the flexible membrane is deployed to create a tapered aerodynamic shape, then aerodynamic drag is reduced and fuel efficiency is improved, but the system complexity increases due to the need for pressurized gas source, controller, and membrane mechanism

Engineering Contradiction:

Improvefuel efficiencyVSAvoidsystem complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies pneumatics by using a pressurized gas source (compressor) to inflate the flexible membrane, leveraging gas compression and pressure control to achieve the desired aerodynamic shape. This pneumatic approach allows for reliable and controllable deployment of the membrane structure, managing the complexity through established pneumatic principles rather than more complex mechanical or electronic actuation systems.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 system effectively reduces aerodynamic drag by dynamically adjusting the trailer's rear profile to optimize fuel efficiency across various operating conditions, improving drivability and reducing environmental impact.

Implementation Method 1

A flexible membrane (101) is selectively inflatable to different aerodynamic profiles... A source of pressurized gas (129) is coupled to the trailer and in fluidic communication with the variable-volume cavity

Methodology Applied

Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

A source of pressurized gas (129) is coupled to the trailer and in fluidic communication with the variable-volume cavity

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11325662B1System for reducing aerodynamic drag forces on a trailer

Publication Date: 2022.05.10 AIR WING 22 LLC

AI summary

A system for reducing drag on a trailer includes a flexible membrane including a perimeter coupled to a rear end of the trailer. A variable-volume cavity is defined between the flexible membrane and the rear end. The system also includes a source of pressurized gas coupled to the trailer and in fluidic communication with the variable-volume cavity, and a controller operable to control a flow of the pressurized gas from the source to the variable-volume cavity such that the flexible membrane is moved from a stowed profile, wherein the flexible membrane is collapsed against the rear end of the trailer, to a first deployed profile, wherein the flexible membrane is maintained in a first pre-selected tapered aerodynamic shape projecting rearward from the rear end.