As the automotive industry moves towards electrification, maximizing energy efficiency has become a key engineering priority. Advances in battery technology, aerodynamics and electric drivetrains continue to extend vehicle range, but another factor also plays an important role in real-world efficiency: tire pressure.
Underinflated tires increase rolling resistance, which means more energy is required to keep the vehicle moving. While this affects all vehicles, it is particularly relevant for battery electric vehicles (BEVs), where energy consumption directly influences how far the vehicle can travel between charges.
Maintaining the manufacturer's recommended tire pressure is therefore not only important for safety and tire performance, but also for supporting overall vehicle energy efficiency.
As a tire rolls, it continuously deforms where it contacts the road surface. Because tire rubber is viscoelastic, not all of the energy used to deform the tire is recovered as it returns to its original shape. Part of that energy is dissipated as heat, creating what is known as rolling resistance.
The level of rolling resistance is influenced by several factors, including tire construction, rubber compound, temperature, road surface and inflation pressure.
Under normal on-road conditions, when tire pressure decreases, the tire typically deforms more as it rolls. This increased deformation can increase rolling resistance, requiring more energy to propel the vehicle.
The underlying tire physics is independent of vehicle powertrain, but rolling resistance contributes directly to the energy required to move a vehicle.
Vehicle load is one of the factors affecting tire rolling resistance. Many battery-electric vehicles carry substantial battery packs, making vehicle mass and tire performance important considerations in overall vehicle energy consumption.
For an EV, higher energy consumption means less driving range from the available battery energy. Reducing avoidable losses, such as increased rolling resistance caused by underinflated tires, can therefore contribute to more efficient use of the energy stored in the battery.
Energy dissipated as heat through rolling resistance cannot be recovered through regenerative braking. Once that energy has been dissipated through the tires, it is no longer available for propulsion.
Tire pressure naturally changes over time. Tires gradually lose air, while changes in ambient temperature also affect inflation pressure. This means that a correctly inflated tire will not necessarily remain at the same pressure throughout its lifetime or across changing operating conditions.
Underinflation can increase rolling resistance and, consequently, vehicle energy consumption. The exact effect depends on factors such as tire design, vehicle load, driving conditions and speed.
For electric vehicles, avoiding unnecessary rolling resistance helps make more efficient use of the energy available in the battery and can contribute to maximizing available driving range.
Because tire pressure can change gradually, a driver may not immediately notice that a tire has become underinflated.
A Tire Pressure Monitoring System (TPMS) is designed to detect tire pressure loss and warn the driver, allowing corrective action to be taken when underinflation occurs.
For vehicle manufacturers, TPMS is an important safety function. Maintaining appropriate tire inflation can also support tire performance and vehicle energy efficiency.
Direct Tire Pressure Monitoring Systems (dTPMS) use dedicated pressure sensors installed in each wheel. These sensors measure absolute tire pressure and transmit the information wirelessly to the vehicle. This architecture requires additional in-wheel hardware, including battery-powered pressure sensors.
NIRA's Tire Pressure Indicator (TPI) takes an indirect, software-based approach.
Rather than measuring absolute tire pressure with dedicated in-wheel sensors, TPI uses signals already available in the vehicle, primarily wheel-speed information, to detect changes in wheel behavior associated with tire pressure loss.
NIRA's algorithms analyze these signals to detect underinflation without requiring dedicated pressure sensors inside the wheels. The system is implemented using existing vehicle sensors and software, reducing the need for additional TPMS hardware and the associated component and lifecycle dependencies.
This software-based architecture can reduce system complexity, component count and dependence on battery-powered in-wheel sensors while fulfilling the fundamental TPMS function of detecting tire pressure loss and warning the driver.
As vehicles become increasingly software-defined, indirect TPMS demonstrates how existing vehicle signals and software algorithms can be used to deliver important vehicle functions without adding dedicated in-wheel sensing hardware.
Read more about NIRA's iTPMS here.
Improving EV range is not only about increasing battery capacity. Reducing avoidable energy losses throughout the vehicle also plays an important role.
Maintaining the manufacturer's recommended tire pressure is one way to reduce unnecessary rolling resistance. Because tire pressure can change over time, monitoring for pressure loss helps drivers identify underinflation and take corrective action.
For manufacturers, NIRA's software-based iTPMS provides an alternative to direct, sensor-based TPMS. By using existing vehicle signals rather than dedicated in-wheel pressure sensors, TPI supports tire pressure monitoring through software while reducing additional hardware and its associated lifecycle dependencies.