Variable Width Wheel Spoke Passage for Drag Reduction
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Solution Overview
Problem
Vehicle wheels with through-openings between spokes for cooling air flow pose a challenge in reducing air resistance, particularly at higher speeds, as they increase fuel consumption without compromising the necessary cooling airflow.
Innovation Solution
The passage openings in the wheel design decrease in width radially when viewed against the direction of rotation, reducing the contact surface for obstructive pressure forces and minimizing the lever arm of these forces relative to the wheel center, thereby reducing the moment of resistance against wheel rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If passage openings between spokes are designed with constant width in the radial direction, then cooling air flow is sufficient, but air resistance and moment of resistance increase
Solution Approach 1:
The passage opening width varies locally along the radial direction, being larger near the wheel rim and smaller near the wheel center. This local variation optimizes both cooling performance (sufficient area at the rim) and aerodynamic performance (reduced resistance near the center), resolving the contradiction between adequate cooling and minimized air resistance.
Solution Approach 2:
The width parameter of the passage opening is changed continuously or stepwise in the radial direction, transitioning from a constant width design to a variable width design. This parameter change allows the passage opening to adapt to different aerodynamic and thermal requirements at different radial positions, reducing the moment of resistance while maintaining cooling effectiveness.
2Reliability
If passage openings have larger width in the radial direction, then cooling performance improves, but the lever arm of pressure force increases resulting in higher moment of resistance
Solution Approach 1:
The passage opening width is optimized locally at different radial positions, with larger width near the rim for cooling and smaller width near the center to reduce the lever arm of pressure forces. This local optimization resolves the contradiction between cooling performance and moment of resistance.
Solution Approach 2:
The passage opening design transitions from a one-dimensional constant width to a two-dimensional variable width profile in the radial direction. This dimensional change allows simultaneous optimization of cooling area and aerodynamic resistance by exploiting the radial dimension.
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 leads to a measurable reduction in fuel consumption by minimizing the moment of resistance caused by air forces, while maintaining sufficient cooling airflow through the wheel.
Implementation Method 1
the width mentioned (of the passage openings in the radial direction) decreases to such an extent and thus the contact surface of the air flow on the wheel when the vehicle is moving in the direction of travel on a vertical aligned and located above the wheel center spoke adjusting pressure force is reduced in such a way that the lever arm of this pressure force with respect to the center point of the vehicle wheel is less than the lever arm of the suction force occurring on the rear side of this spoke
Data Source
Figure 1~3
AI summary
The vehicle wheel has a passage opening (4), particularly for cooling air flow. The width (B-R1,B-R2) averages against the rotary direction (5) of the wheel during forward drive of the vehicle. The center points (M-1,M-2) of the opposite rotation direction observed in radial direction (R) move following virtual segments of the passage opening quasi in direction of the wheel center point (1).