Techniques to Control Tire Temperature

1. Rubber Compositions with Reduced Hysteresis and Heat Generation

Tire engineers have long faced a fundamental challenge in rubber formulation: optimizing for either wear resistance or low heat buildup, rarely achieving both simultaneously. Traditional approaches to enhancing wear characteristics - such as increasing carbon black content or decreasing its particle size - typically result in increased hysteresis and consequent heat generation. This trade-off creates significant design constraints, particularly for high-performance tires where durability cannot come at the expense of energy efficiency.

Recent innovations address this dilemma through strategic material selection and precise formulation. One notable approach involves a rubber blend containing both natural rubber and butadiene rubber, with natural rubber content maintained below 80%. The technical breakthrough lies not in the rubber matrix itself but in the selective combination of carbon black types. This approach utilizes Carbon Black A with high specific surface area and high toluene coloring transmittance alongside Carbon Black B with moderate surface area, while minimizing or eliminating other carbon black varieties.

The synergistic effect achieved through this combination is particularly noteworthy: Carbon Black A contributes to enhanced wear resistance and improved dispersion throughout the rubber matrix, while Carbon Black B reduces hysteresis and subsequent heat buildup. This balanced formulation represents a significant advancement in resolving the traditional performance compromise between mechanical durability and thermal efficiency.

Beyond carbon black optimization, molecular-level modifications of the rubber matrix offer another pathway to reduced heat generation. Conventional rubber compounds exhibit substantial hysteresis loss, particularly at low strains, where deformation energy dissipates as heat and negatively impacts tire fuel efficiency. However, high strain hysteresis remains necessary for maintaining durability under mechanical stress.

A chemical innovation in this domain introduces thiadiazole, a sulfur-containing heterocyclic compound, into rubber formulations. This compound selectively reduces hysteresis loss at low strain amplitudes without compromising high strain performance. The result is a rubber composition that generates less internal heat during normal rolling conditions while preserving structural integrity during high-stress scenarios. Manufacturers can further fine-tune viscoelastic properties by incorporating carbon black with varying nitrogen adsorption specific surface areas, creating a versatile platform for application-specific rubber components.

2. Thermally Optimized Tread and Sidewall Designs

Thermal degradation presents a persistent challenge in tire design, particularly affecting tread and sidewall regions where heat accumulation leads to increased hardness and diminished performance over time. This issue becomes especially critical in autonomous and shared mobility vehicles, where maintenance intervals may be irregular.

An innovative elastomer composition addresses this challenge by integrating styrene elastomer with hollow urethane particles. This formulation specifically targets heat aging effects, which typically manifest as increased rubber stiffness and reduced wet grip performance. The composition's effectiveness is quantified through a defined performance condition: limiting the percentage increase in stress at 100% elongation after heat aging.

What distinguishes this approach from conventional solutions is the functional role of the hollow urethane particles in controlling modulus increase. These particles create a microstructure that maintains flexibility even after prolonged thermal exposure, thereby preserving wet grip characteristics. This property becomes particularly valuable in transportation systems where tire maintenance may not occur at optimal intervals.

Heat management becomes further complicated by the integration of noise dampers within the tire cavity. While these dampers effectively reduce cavity resonance by converting vibrational energy to heat, they inadvertently create localized thermal stress in adjacent tread rubber.

To address this thermal challenge without sacrificing acoustic benefits, researchers have developed a multi-layered tread architecture. This design features an outer tread rubber optimized for grip and an inner tread rubber with reduced loss tangent to minimize hysteretic heat generation. Some configurations incorporate a middle layer with higher loss tangent to create a thermal gradient across the tread profile. The innovation centers on this thermally stratified tread rubber architecture, which distributes thermal load more effectively while maintaining both durability and acoustic performance.

The chemical approach to thermal optimization has also advanced through improved heat aging resistance of vulcanized rubber. While traditional antiaging agents provide limited protection against oxidative and ozone-induced degradation, newer formulations incorporate small amounts of compounds such as caffeic acid or dimethoxycinnamic acid. These compounds can be integrated with existing antioxidants to significantly enhance mechanical property retention after thermal aging, as evidenced by improved breaking elongation rates. The integration of novel cinnamic acid derivatives offers a scalable solution that can be implemented without substantial modifications to standard manufacturing processes.

3. Active Tire Temperature Control Using Thermoelectric Systems

The evolution of vehicle performance characteristics - including higher speeds, extended travel distances, and operation in diverse environmental conditions - has intensified the risk of tire overheating. Traditional monitoring systems like TPMS provide only passive pressure data and require manual intervention, failing to address dynamic temperature fluctuations that can compromise tire integrity.

A sophisticated response to this limitation comes in the form of a thermoelectric cooling/heating system integrated inside the tire. This system represents a shift from passive monitoring to active thermal management through several integrated components. A temperature sensor continuously monitors internal tire conditions, transmitting data to an intelligent controller that activates semiconductor cold and hot fins as needed. The system achieves energy independence through a suspended hub generator that harvests kinetic energy from wheel rotation.

This active approach offers multiple advantages over conventional solutions. By dynamically regulating thermal conditions, the system not only maintains optimal pressure but also reduces tire wear, improves fuel efficiency, and minimizes blowout risk. The self-sustaining power generation eliminates the need for external energy sources, making it particularly suitable for long-distance and autonomous applications.

In contrast to internal thermal management, another innovation focuses on a fluid-free, gas-free automatic thermoelectric cooling mechanism mounted directly on the tire exterior. This approach addresses the environmental and operational limitations of traditional cooling methods such as water spraying or nitrogen injection. The system employs a semiconductor cooling device controlled by a wireless monitoring unit that activates when tire temperatures exceed predetermined thresholds.

The external mounting configuration offers distinct benefits: it requires no user interaction, operates silently, and avoids invasive modifications to the tire structure. This targeted thermal management significantly reduces puncture risk, extends service life, and enhances driving safety, particularly in high-temperature environments where conventional tires are prone to failure.

A third approach focuses on surface cooling through a cold air duct system with directional control. This system addresses the intense heat accumulation on external tire surfaces during prolonged or high-speed driving. Infrared sensors monitor surface temperatures and trigger a cold air generator when limits are exceeded. The system's precision comes from stepper motors and gear-actuated ducts that direct airflow specifically to high-temperature zones.

By integrating with the vehicle's existing radiator system, this solution maintains surface temperatures within design specifications. The resulting benefits include improved braking efficiency, enhanced fuel economy, and extended tire life - advantages that become increasingly significant as vehicles trend toward higher performance specifications.

4. Air-Based Cooling Systems Triggered by Temperature Sensors

Solid tires used in industrial and military vehicles present unique thermal management challenges due to their prolonged ground contact and friction characteristics under high-load, low-speed operations. The resulting heat accumulation can accelerate structural degradation and reduce service life.

An intelligent thermal management system addresses these challenges through real-time monitoring and automated response. The system employs a temperature sensor mounted directly on the tire to continuously assess thermal conditions. When elevated temperatures are detected, a controller activates a fan that circulates filtered air through a bellows-style wind box, directing cooling airflow onto the tire surface.

The system's adaptability to environmental conditions is particularly noteworthy. A rain-responsive auto-closure mechanism utilizes a rain sensor connected to a motorized assembly that closes the wind box door during precipitation, preventing water ingress and protecting internal components from corrosion. This environmental responsiveness enhances system longevity while reducing maintenance requirements, making it especially suitable for deployment in harsh operational environments.

Internal heat buildup in pneumatic tires presents different challenges, especially under high ambient temperatures or repeated braking scenarios. The resulting thermal stress can lead to rupture and vehicle instability. A novel cooling approach integrates a cold air injection system using a vortex tube to manage internal tire temperature.

This system continuously monitors temperature via an internal sensor and employs a solenoid valve to inject cold air when thresholds are exceeded. The vortex tube, powered by compressed air from the vehicle's engine, creates temperature separation, directing the cold air stream into the tire cavity. Beyond preventing catastrophic failure, this approach extends tire lifespan by reducing material fatigue from thermal cycling. The system's adaptive response to real-time temperature data ensures consistent performance without requiring driver intervention.

Heavy commercial vehicles face particularly severe thermal challenges due to their operational characteristics. Low tire pressure combined with increased friction can lead to accelerated aging or catastrophic wheel hub failure. A sensor-driven water cooling system addresses these risks through integrated monitoring and targeted cooling.

Each wheel is equipped with temperature and pressure sensors connected to a dedicated water tank and nozzle system. When sensors detect overheating, solenoid valves regulate water flow for precise cooling. The system demonstrates environmental awareness by utilizing collected rain or snow water, and prevents thermal shock by regulating water temperature through the vehicle's heating system.

The modular architecture creates a one-to-one correspondence between sensors and actuators, allowing for scalable deployment across different vehicle configurations. This closed-loop approach not only enhances operational safety but also optimizes resource utilization through environmental water recycling.

5. Integrated Temperature Control in Non-Pneumatic and Electric Wheels

Non-pneumatic electric wheels in modern electric vehicles present complex thermal management challenges that span both propulsion and structural components. Hub motors frequently experience elevated winding temperatures during operation, accelerating insulation degradation and reducing motor lifespan. Simultaneously, tire components exposed to temperature extremes suffer from accelerated aging at high temperatures and compromised wear resistance and safety at low temperatures.

The integrated temperature control system addresses these multifaceted challenges through a comprehensive thermal management architecture embedded within the wheel structure. This system incorporates several functional elements: a heat sink attached directly to the motor that transfers excess thermal energy to a circulating cooling fluid; a heat dissipation module positioned inside the wheel shell; and strategically located vents that exhaust heated fluid.

The system's adaptive capability derives from a thermostat-regulated valve that modulates fluid flow based on real-time motor temperature readings. For cold-weather operation, a rim-integrated heating element activates in response to low tire temperatures. This bidirectional thermal management ensures optimal operating conditions across all wheel components regardless of ambient conditions or operational demands.

Non-pneumatic wheels in material handling equipment such as forklifts encounter different thermal challenges due to their compact dimensions, high load requirements, and continuous duty cycles. Traditional solid steel or cast iron hubs conduct heat directly from bearings to the elastomer tire, compromising both the adhesive bond and the elastomer's structural properties.

A thermally optimized hub architecture addresses these issues through material selection and geometric design that effectively decouples heat-generating components. The hub utilizes low-mass, high thermal conductivity materials such as extruded aluminum and incorporates axial passageways that enhance both convective and conductive cooling. The tire interface employs chemical bonding rather than mechanical interlocks, reducing stress concentrations and improving thermal durability.

The development of a quantitative "Heat Factor" metric represents a significant advancement in hub design optimization. This factor balances mass, specific heat capacity, and surface area to maximize heat rejection efficiency. By applying this metric to design iterations, engineers can systematically improve thermal performance while maintaining structural integrity under high-load conditions.

These integrated thermal management approaches demonstrate how specialized solutions can address the unique challenges of non-pneumatic and electric wheel applications. By managing the distinct thermal dynamics of both propulsion and load-bearing functions, these systems extend component life while enhancing safety and operational efficiency in demanding environments.