Motorcycle Shroud Curvature for Airflow and Stability

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Solution Overview

Problem

Conventional motorcycles face challenges in maximizing air flow to the engine while minimizing the force that causes shrouds to separate from the fuel tank, leading to inefficient air guidance and potential instability during travel.

Innovation Solution

The design includes shrouds fixed to the fuel tank that extend diagonally forward and outward, with a wider distance between their front ends than the fuel tank's width, and an outermost portion located further forward than the fixation point, enhancing air guidance to the engine and reducing separation forces by leveraging airflow dynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the shrouds are arranged to extend forward from the fuel tank with a larger distance between front ends than the fuel tank width, then the amount of air guided to the engine is increased, but the force acting outward on the fixation position increases causing the shroud to separate from the fuel tank

Engineering Contradiction:
Improveamount of airVSAvoidoutward force on fixation position
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The shroud is designed with a curved outer surface that swells outward in the right-left direction, creating a streamlined shape that guides airflow smoothly around the engine while reducing turbulent forces that would cause separation at the fixation position

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The shroud extends not only forward from the fuel tank but also curves outward in the right-left direction, utilizing three-dimensional spatial arrangement to maximize air intake volume while distributing aerodynamic forces away from the fixation point

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

2Force

If the outermost portion of the shroud is located further forward than the fixation position, then the force generated by airflow against the shroud surface increases to reduce separation tendency, but the structural complexity of the shroud increases

Engineering Contradiction:
Improveforce generated by airflowVSAvoidshroud structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The shroud employs a smooth curved profile where the outermost portion naturally protrudes forward due to the curvature geometry, generating beneficial aerodynamic forces without requiring additional structural elements or complex mechanisms

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The shroud's cross-sectional area and curvature parameters are optimized along its length, with the outermost portion positioned forward to maximize airflow capture while maintaining a simple continuous structure that avoids complexity

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

This configuration increases air flow to the engine and reduces the force that tends to separate the shrouds from the fuel tank, resulting in improved airflow efficiency and stability during motorcycle operation.

Implementation Method 1

The right and left shrouds are formed to extend forward from the fuel tank, and guide, to the engine, air which flows rearward over the front fender during running of the motorcycle

Methodology Applied
Scientific EffectAirflow guidance:

Implementation Method 2

a force which tends to make the shroud close to the center of the right-left direction becomes larger, the force being generated due to the air which is brought against outer surface of front portion of the shroud

Methodology Applied
Scientific EffectAerodynamic force:

Data Source

PatentEP2230120B1Motorcycle
Publication Date: 2019.10.16 YAMAHA MOTOR CO LTD
  • EP2230120B1 patent drawingFigure 1
  • EP2230120B1 patent drawingFigure 2
  • EP2230120B1 patent drawingFigure 3

AI summary

Provided is a motorcycle (1) capable of reducing a force, which causes shrouds (2) to be separated from side surfaces of a fuel tank (3), and of increasing an amount of air guided to an engine. The motorcycle (1) is provided with shrouds (2) fixed onto side surfaces (3a) of a fuel tank (3), respectively. The shrouds (2) are arranged to extend forward from the fuel tank (3). Further, each of the shrouds (2) is curved so as to swell outwardly in a right-left direction, and has an outermost portion (22c) that is located furthest outward in the right-left direction between a front end (22d) and a rear end of each of the shrouds (2). The outermost portion (22c) is located further forward than a fixation portion (2a,2b) at which each of the shrouds (2) is fixed to the fuel tank (3). A distance (L1) between the front end (22d) of the left shroud (2) and the front end (22d) of the right shroud (2) is larger than a width (L2) in the right-left direction of the fuel tank (3).