Straddled Vehicle Cowl Design for Cooling and Drag Reduction
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Solution Overview
Problem
Existing straddled vehicles with front cowl designs face challenges in improving the cooling performance of heat exchangers while minimizing aerodynamic drag during driving.
Innovation Solution
The design incorporates a front cowl with a depression recessed rearward, an air passage formed downward of the cowl lower portion and upward of the front wheel, and a heat exchanger positioned rearward of the air passage. The cowl upper portion has a central portion recessed rearward, promoting the formation of a high pressure area upward, which directs airflow smoothly toward the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a front cowl with a depression is used to reduce aerodynamic drag, then aerodynamic drag is reduced, but the high pressure area formed forward of the depression causes airflow to avoid flowing downward toward the heat exchanger, worsening cooling performance
Solution Approach 1:
The invention changes the vertical positioning relationship between the cowl upper portion and cowl lower portion. By making the second front end of the cowl lower portion extend forward beyond the first front end of the cowl upper portion, the high pressure area is redirected to a higher position, allowing airflow to flow downward through the air passage toward the heat exchanger while maintaining aerodynamic drag reduction.
2Loss of energy
If the high pressure area is formed directly in front of the depression, then aerodynamic drag is reduced, but airflow is less likely to flow downward of the cowl lower portion toward the radiator, worsening cooling performance
Solution Approach 1:
The invention utilizes vertical positioning by extending the cowl lower portion's second front end forward beyond the cowl upper portion's first front end. This dimensional change in vertical arrangement shifts the high pressure area formation to a higher position, enabling airflow to naturally flow downward through the air passage to cool the heat exchanger while preserving aerodynamic drag reduction.
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 enhances the cooling performance of the heat exchanger by ensuring a smooth airflow supply while reducing aerodynamic drag during driving.
Implementation Method 1
it is possible to reduce the aerodynamic drag during driving
Implementation Method 2
airflow generated by driving
Implementation Method 3
the area forward of the front cowl is an area of high pressure
Data Source
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AI summary
There is described a straddled vehicle, wherein cooling performance of a heat exchanger is improved while reducing aerodynamic drag during driving, in parituclar a motorcycle (1) includinga front cowl (20) that has a depression (30) recessed rearward;. the front cowl (20) including a cowl upper portion (20U) located upward of the depression (30), and a cowl lower portion (20D) located downward of the depression (30);. an air passage (18) being formed downward of the cowl lower portion (20D) and upward of a front wheel (6);. a radiator (15) being arranged rearward of an air passage (18); on a vertical end surface passing through a vehicle center line of the front cowl (20), a central portion (23) of the cowl upper portion (20U) has a first front end (31) projecting forward, and the cowl lower portion (20D) having a second front end (32) located forward relative to the first front end (31).