Straddle Vehicle Radiator Side Cowl Aerodynamic Design
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Solution Overview
Problem
Conventional straddle type vehicles with side radiators have a large frontal projected area, leading to increased running resistance, which cannot be reduced without compromising exhaust wind efficiency due to the fixed arrangement of the exhaust wind port.
Innovation Solution
The design incorporates a radiator side cowl with a swelling face portion, a concave face portion, and a stepped portion that extends along the upper edge, creating a stepped-portion exhaust wind port, along with an under cowl with a lower side exhaust wind port and a cutout portion to enhance exhaust wind efficiency while minimizing the frontal projected area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side cowl is arranged to protrude in the width direction to accommodate the exhaust wind port, then the exhaust wind can be discharged efficiently, but the frontal projected area increases and running resistance increases
Solution Approach 1:
The exhaust wind port is repositioned from the lateral surface to the upper surface of the side cowl, utilizing the vertical dimension instead of the width direction. This allows exhaust wind discharge without increasing the frontal projected area, thereby reducing running resistance while maintaining exhaust efficiency
Solution Approach 2:
The side cowl is divided into multiple functional surfaces including a swelling face portion, a concave face portion, and a stepped portion. This segmentation allows each portion to serve specific aerodynamic functions, with the stepped portion creating the exhaust wind port that directs exhaust wind upward and rearward without lateral protrusion
2Force
If the amount of protrusion of the side cowl in the width direction is reduced to decrease running resistance, then the frontal projected area is reduced, but the space between the side radiator and the outside edge of the exhaust wind port becomes narrower, decreasing exhaust wind efficiency
Solution Approach 1:
The exhaust wind port is positioned on the upper surface of the side cowl rather than the lateral surface, utilizing the vertical dimension to create discharge space. This eliminates the need for lateral protrusion while maintaining adequate space for exhaust wind flow between the radiator and the cowl edge
Solution Approach 2:
The side cowl features a localized swelling face portion with a smooth surface that promotes airflow, combined with a stepped portion that creates the exhaust wind port. This local structural differentiation optimizes both aerodynamic performance and exhaust wind discharge without requiring overall lateral protrusion
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 reduces running resistance by allowing smooth and efficient discharge of exhaust wind, maintaining high exhaust wind efficiency and extending the exhaust wind port area, thereby improving airflow and reducing pressure drag.
Implementation Method 1
the swelling face portion allows the traveling wind to flow rearward smoothly as well as with a fast flow velocity
Implementation Method 2
the concave face portion arranged in front of and above the radiator in a side view and having a concaved surface inside in the width direction of the vehicle
Implementation Method 3
the stepped-portion exhaust wind port arranged behind the concave face portion as well as above the stepped portion and functioning as an exhaust wind port
Data Source
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AI summary
It is an object of the present invention to ensure the exhaust wind efficiency of the radiator arranged on the side of the body frame while reducing the running resistance by limiting the frontal projected area of the vehicle. In a straddle type vehicle (1) which has a body frame (5); an engine (20); a radiator (21) arranged on the side of the body frame (5); and a radiator side cowl (50) arranged on the outer side of the radiator (21) and having an exhaust wind port which faces the radiator (21), and wherein an outside edge in the width direction of the vehicle (51a) of the exhaust wind port is arranged with a space from the radiator (21), the radiator side cowl (50) comprises a swelling face portion (52) disposed on the lower portion thereof and swelling outward in the width direction of the vehicle with a smooth surface in the front-and-rear direction; a concave face portion (54) arranged in front of and above said radiator (21) in a side view and having a concaved surface inside in the width direction of the vehicle; a stepped portion (56) extending in the width direction of the vehicle along an upper edge (52a) of the swelling face portion (52) as well as joining the swelling face portion (52) and the concave face portion (54); and a stepped-portion exhaust wind port (60) arranged behind the concave face portion (54) as well as above the stepped portion (56) and functioning as the exhaust wind port.