Tire inflation pressure has a relevant impact on fuel consumption and tire wear, and therefore affects both CO2 emissions and the total cost of ownership (TCO). The latter is extremely important in the case of commercial vehicles, where the cost of fuel is responsible for about 30% of the TCO.
A possible advanced central tire inflation system, which is able to inflate and deflate tires autonomously, as part of a smart energy management system and as an active safety device, has been studied. This system allows misuse due to underinflation to be avoided and adapts the tires to the current working conditions of the vehicle. For instance, the tire pressure can be adapted according to the carried load or during tire warm-up. An on board software is able to evaluate the working conditions of the vehicle and select the tire pressure that minimizes the energy expense, the TCO, or the braking distance, according to a multi-objective optimization strategy.
A simulation tool has been set up to evaluate the effects of tire pressure on fuel consumption and tire wear. The software simulates a reference cycle at different tire pressures and varies the tire pressure along a cycle. The tool also takes into account the dynamics of the actuations, e.g., the time required to reach a target pressure, starting from a certain condition. Therefore, an assessment of the effect of some pressure management strategies, with respect to a reference case, has been performed on different driving cycles. The study has been conducted on both a high-duty vehicle and on a light-duty one. The results obtained on the reference cycles have been combined to calculate the impact on the annual TCO.
