Tire Sidewall Protuberance Geometry for Lower Wheel Drag
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aerodynamic drag generated by the wheels of vehicles, particularly due to turbulence at the connection between the tire and its mounting rim, increases fuel consumption and CO2 emissions, while existing protective cords cause geometric discontinuities that exacerbate this issue.
Innovation Solution
Optimizing the geometric positioning and design of a sidewall protuberance relative to the rim flange, with specific dimensions and configurations to minimize turbulence and maintain aerodynamic continuity, including radial and axial distances, angles, and contact points, ensuring effective protection and ease of mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective cord is arranged in the radially inner part of the tire sidewall to protect the connection between tire and rim, then the protection of the rim flange and tire bead is improved, but geometric discontinuity is created between the sidewall and rim flange, generating turbulence and increasing aerodynamic drag
Solution Approach 1:
The invention changes the geometric parameters of the protective cord by positioning its radially inner end at a specific distance (≤10mm inside or ≤4mm outside the radially outermost point of the rim flange) and defining its contour with specific curvature radius (≥15mm). These parameter optimizations reduce the geometric discontinuity and turbulence generation while maintaining protective function.
Solution Approach 2:
The protective cord is designed with non-uniform cross-sectional thickness, being thickest at the radially inner end and gradually thinning toward the axially outer end. This local quality variation allows the cord to provide maximum protection where needed (at the vulnerable bead-rim connection) while minimizing aerodynamic disruption at the outer regions.
2Reliability
If the radially inner end of the protuberance is positioned further inside the rim flange to enhance protection, then the protection effect is improved, but the geometric discontinuity increases and aerodynamic drag increases
Solution Approach 1:
The invention establishes an optimal parameter range for the radial position of the protuberance's inner end (≤10mm inside the rim flange's outermost point), balancing protection and aerodynamics. This quantified parameter optimization prevents excessive intrusion into the rim flange space while ensuring adequate protection coverage.
Solution Approach 2:
The protuberance contour is designed with a minimum curvature radius of 15mm at the radially inner end, creating a smooth, rounded transition rather than a sharp edge. This curvature reduces flow separation and turbulence in the aerodynamic field while maintaining structural protection capability.
3Object-generated harmful factors
If perfectly smooth sidewalls in continuity with the rim flange are used, then aerodynamic drag is minimized, but protection against impacts and damage to the tire-rim connection is reduced
Solution Approach 1:
The protective cord acts as an intermediary element between the tire sidewall and rim flange. It provides mechanical protection to the vulnerable connection zone while its optimized geometry (smooth contours, appropriate positioning) minimizes its aerodynamic interference, effectively mediating between protection and aerodynamic efficiency requirements.
Solution Approach 2:
The protective cord is designed with flexible, gradual thickness variation along its length rather than rigid uniform structure. This dynamic geometry allows it to adapt to both protective functions and aerodynamic flow patterns, reducing turbulence while maintaining protection.
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
Reduces aerodynamic drag, thereby decreasing fuel consumption and CO2 emissions, while maintaining tire protection and ease of mounting, with optimized aerodynamic efficiency and reduced energy dissipation.
Implementation Method 1
the aerodynamic drag applying to a wheel is generated by the turbulence of air flow around the wheel
Implementation Method 2
This aerodynamic drag corresponds to the aerodynamic resistance which opposes the forward motion of the object in the fluid
Data Source
AI summary
A tire (1), intended in particular for a private passenger vehicle and comprising at least one sidewall (3) with a protuberance of the sidewall (3) close to the connection of the tire with its mounting rim (2), and intended to reduce the aerodynamic drag and hence the resistance to forward motion of the wheel, in order to contribute to the reduction in fuel consumption and hence to the reduction in CO2 emissions. According to the invention, when the tire (1) is mounted on the rim (2) and inflated to a pressure as defined by the “ETRTO” standard, the radially inner end I of the protuberance (6) is positioned radially inside the radially outermost point J of the rim flange (21) at a radial distance H1 at most equal to 10 mm, or radially outside the radially outermost point J of the rim flange (21) at a radial distance H1 at most equal to 4 mm.