Commercial Vehicle Wheel Thermal Insulation Reduces Rolling Resistance
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Solution Overview
Problem
Commercial vehicle tires experience high rolling resistance due to heat dissipation, which increases tire temperature and reduces structural durability, while existing thermal insulation methods either compromise durability or are inefficient.
Innovation Solution
A thermally insulated motor vehicle wheel with a metal rim and a pneumatic tire featuring a heat-insulating layer, such as open-cell polyurethane foam, applied to the rim, optimizing rolling resistance without detrimental effects on durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thermal insulation is applied to the rim or tire surface, then rolling resistance is reduced through increased tire temperature, but structural durability deteriorates due to excessive heat accumulation
Solution Approach 1:
The patent applies open-cell foam material (such as polyurethane foam) as thermal insulation on the rim surface. The porous structure of the foam provides thermal insulation to increase tire temperature and reduce rolling resistance, while the open-cell structure allows for heat dissipation that prevents excessive temperature accumulation, thereby maintaining tire structural durability.
Solution Approach 2:
The thermal insulation is applied locally on the rim surface in the rim well area, rather than uniformly across the entire rim. This localized application provides thermal insulation where needed to increase tire temperature, while leaving other areas without insulation to allow heat dissipation, thus balancing rolling resistance reduction with durability maintenance.
2Temperature
If high thermal conductivity rim material is used, then heat dissipation is improved, but rolling resistance increases due to lower tire temperature
Solution Approach 1:
The patent introduces thermal insulation material as an intermediary layer between the high thermal conductivity rim and the tire. This intermediary layer moderates the heat transfer, preventing excessive heat dissipation from the rim to the environment, thereby maintaining higher tire temperature and reducing rolling resistance.
3Loss of energy
If thermal insulation layers are added to existing tires, then rolling resistance is reduced, but device complexity increases
Solution Approach 1:
The patent combines the thermal insulation layer with the rim structure itself, integrating the insulation into the wheel assembly rather than adding it as a separate component on the tire. This merging approach reduces device complexity by consolidating functions within the existing rim structure.
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 solution significantly reduces rolling resistance, maintaining structural durability by increasing tire interior temperature effectively, achieving a rolling resistance of ≤6.04 kg/t, corresponding to the EU label C or better, and reducing fuel consumption by approximately 0.5%.
Implementation Method 1
the high thermal conductivity of the rim material commonly used, there is a significant transfer of heat from the wheel into the environment via the rim surface
Implementation Method 2
the pneumatic vehicle tire heats up during use due to hysteresis losses
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a motor vehicle wheel (22) comprising a metal rim (23) and a pneumatic tire (6) mounted on this rim (23), wherein thermal insulation in the form of an additional heat-insulating layer (5a, 5b, 5c, 14a, 14b) is arranged on the surface of the rim (23) and/or on the surface of the pneumatic tire (6). The bare pneumatic tire (6), i.e., the pneumatic tire without the additional heat-insulating layer, has a rolling resistance of ≤ 6.04 kg/t, the rolling resistance being determined according to the rolling resistance test ISO 28580.