Front Cowl Headlight Openings for Saddle Vehicle Airflow Separation

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Solution Overview

Problem

Saddle riding type vehicles experience increased airflow resistance and turning difficulties due to the 'stick phenomenon' where air flowing along the front cowl surface adheres to the vehicle, requiring excessive leaning force for turning.

Innovation Solution

The front cowl structure incorporates headlight neighboring openings that communicate with the inside of the cowl, disrupting laminar airflow over the lens surfaces and allowing airflow separation, along with symmetrical side openings that guide airflow outwards, reducing resistance and enhancing turning performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the front cowl is designed to maintain laminar airflow to minimize resistance, then airflow resistance is reduced, but the stick phenomenon occurs causing increased resistance during turning operations

Engineering Contradiction:
Improveairflow resistanceVSAvoidturning operation
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The front cowl is divided into multiple functional zones: a headlight neighboring opening (first opening) that segments the airflow path to create separation points, and side openings (second openings) that further divide and direct airflow outward. This segmentation disrupts the continuous laminar flow that causes the stick phenomenon, allowing the airflow to separate from the cowl surface and reduce turning resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces airflow control in the vehicle width direction through side openings, adding a lateral dimension to airflow management. This causes airflow to jet outward in the width direction, creating forced separation from the cowl surface and eliminating the stick phenomenon that occurs with conventional streamlined designs.

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

2Productivity

If the front cowl surface is streamlined to guide airflow smoothly, then aerodynamic efficiency is improved, but turning performance deteriorates due to excessive leaning force requirement

Engineering Contradiction:
Improveaerodynamic efficiencyVSAvoidleaning force
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The invention extracts airflow from the conventional smooth cowl surface path by introducing headlight neighboring openings and side openings. These openings extract portions of the airflow and redirect them outward, creating separation zones that prevent the airflow from adhering to the cowl surface during turning, thereby reducing the leaning force required.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the harmful stick phenomenon into a beneficial airflow separation mechanism. By strategically positioning openings to create controlled separation points, the design transforms what was previously a source of resistance into a mechanism that actively reduces drag and improves turning performance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If air inlet openings are added to the front cowl, then airflow separation is improved, but device complexity increases

Engineering Contradiction:
Improveturning performanceVSAvoidcowl structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The headlight neighboring opening serves multiple functions: it acts as an air inlet for airflow separation, provides structural integration with the headlight assembly, and creates a separation point without requiring additional components. The side openings similarly serve both aerodynamic separation and structural purposes, reducing overall device complexity.

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

Solution Approach 2:

The invention merges the airflow control function with existing structural elements of the front cowl, particularly the headlight mounting areas and side cowl structures. By integrating openings into these existing features rather than adding separate components, the design achieves airflow separation while minimizing increases in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 design reduces the force required for turning by effectively separating airflow from the vehicle body, improving turning performance and maintaining uniformity on both sides.

Implementation Method 1

the airflow is a laminar flow in order to minimize airflow resistance as much as possible

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 2

The airflow can then be separated from the vehicle body in rearward portions of the headlights

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 3

the side openings are formed to allow the airflow that has flowed in through the headlight neighboring openings to flow out of the front cowl in the vehicle width direction

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP2712794B1Front cowl structure for saddle riding type vehicle
Publication Date: 2016.10.26 HONDA MOTOR CO LTD
  • EP2712794B1 patent drawingFigure 1
  • EP2712794B1 patent drawingFigure 2
  • EP2712794B1 patent drawingFigure 3

AI summary

To provide a front cowl structure for a saddle riding type vehicle, capable of containing a stick phenomenon of an airflow in the front cowl. A pair of headlights (18) is disposed on leading end lateral sides of a front cowl (10). Each of the headlights (18) has a lens surface (18a) that includes at least a part formed to face downwardly. A front cowl structure has headlight neighboring openings (10h) formed at the rear portion side of the lens surfaces (18a) of the headlights (18), the headlight neighboring openings (10h) communicating with an inside of the front cowl (10).