Pneumatic Tire Protrusions for Drag Reduction
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Solution Overview
Problem
Pneumatic tires with projection portions, ridges, or circumferential protrusions often experience a decrease in uniformity, leading to increased air resistance and reduced fuel economy, while existing solutions fail to maintain good uniformity while reducing lift and air resistance effectively.
Innovation Solution
A pneumatic tire design featuring protrusion portions that extend along the tire side surface, intersecting both the tire circumferential and radial directions, with an intermediate portion having the highest projection height and tip portions with the lowest, disposed radially outer and inner to the tire maximum width position, and a specific ratio of total width to outer diameter, which generates turbulent air flow to reduce lift and air resistance while maintaining uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If projection portions, ridges, or circumferential protrusions are added to the tire sidewall to reduce lift and air resistance, then aerodynamic performance is improved, but uniformity in the tire circumferential direction deteriorates
Solution Approach 1:
The protrusion portions are strategically positioned only in the upper region of the tire sidewall (above the equatorial plane) rather than uniformly distributed around the entire tire. This localized approach creates turbulent flow where needed for aerodynamic benefit while avoiding uniformity issues that would result from circumferential distribution. The protrusions are placed specifically in the region where air flow manipulation most effectively reduces drag and lift.
Solution Approach 2:
The tire design employs asymmetric distribution of protrusion portions, with features concentrated on one side of the tire rather than symmetric placement. This asymmetric configuration generates beneficial aerodynamic effects by creating controlled turbulence in specific flow regions while maintaining overall tire uniformity. The asymmetric pattern prevents periodic uniformity problems that would arise from symmetric, evenly-spaced protrusions around the tire circumference.
2Loss of energy
If the total width of the pneumatic tire is decreased to reduce air resistance, then fuel economy is improved, but other performance characteristics may be compromised
Solution Approach 1:
The invention modifies the aerodynamic parameters of the tire by adding protrusion portions that change the air flow characteristics around the tire. These parameter changes create turbulent flow patterns that reduce pressure drag and lift forces, achieving fuel economy improvement without requiring a reduction in tire width. The protrusions effectively change the aerodynamic 'shape factor' of the tire while maintaining its dimensional specifications.
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
The design effectively reduces lift and air resistance, improves steering stability, and maintains uniformity by minimizing sudden mass changes and optimizing air flow around the tire, leading to improved fuel economy and ride comfort.
Implementation Method 1
the protrusion portions make the air turbulent and minimize the slow air flow around the pneumatic tire
Implementation Method 2
the spread of passing air is suppressed, air resistance of the pneumatic tire can be reduced
Implementation Method 3
generating a downforce that presses down the top of a tread portion
Implementation Method 4
by the downforce being generated, lift, a force that lifts the vehicle upwards, is reduced
Data Source
AI summary
A pneumatic tire comprises a plurality of protrusion portions extending along a tire side surface of a tire side portion in a direction that intersects a tire circumferential direction and a tire radial direction; the plurality of protrusion portions each including an intermediate portion in an extension direction that includes a highest position of projection height from the tire side surface, and tip portions on either side of the intermediate portion in the extension direction that include a lowest position of projection height from the tire side surface; and the plurality of protrusion portions including a radially outer protrusion portion with at least the intermediate portion disposed outward of a tire maximum width position in the tire radial direction, and a radially inner protrusion portion with at least the intermediate portion disposed inward of the tire maximum width position in the tire radial direction.