Introducing the Modified Tire Power Loss and Resistant Force Regarding Longitudinal Slip

Abstract

Investigation of vehicle resistant forces and power losses is of crucial importance owing to current state of energy consumption in transport sector. Meanwhile, considerable portion of resistant forces in a ground vehicle is traced back to tires. Pneumatic tires are known to be a source of energy dissipation as a consequence of their viscoelastic nature. The current study aims to provide a modification to tire resistance by considering the power loss in a tire due to longitudinal slip. The modified tire resistance is comprised of rolling resistance and a newly introduced resistance caused by tire slip, called slip resistance. The physical model is chosen for parameters sensitivity study since the tractive force is described in this model via tangible physical parameters, e.g. tire tangential stiffness, coefficient of friction, and contact patch length. Hence, the tire physical model is capable to investigate the influence of different parameters such as coefficient of friction, normal load, and inflation pressure on dependency of tractive force upon longitudinal slip. The results show that tractive force is a determining factor in the modified tire resistance. In addition, it is seen that behavior of the modified tire resistance undergoes qualitative changes so that for a specified tractive force, it might be a strictly decreasing function of the mentioned parameters. But as the tractive force gradually increases, it might be changed to a non-monotonic function and after that to a strictly increasing function of the above parameters. Furthermore, the results are validated by measuring the vehicle constant-speed fuel consumption experimentally. History

Energy reduction by power loss minimisation through wheel torque allocation in electric vehicles: a simulation-based approach

“…The slip results in a slip velocity that is defined as the difference between the translational velocity of the wheel centre and rotational velocity of the wheel multiplied with the effective wheel radius. The slip velocity gives rise to power loss characterised by the following formula [17]:…”

A novel method to improve vehicle energy efficiency: Minimization of tire power loss

“…38 Therefore, the physical model can be simply adapted to the change of physical parameters, whereas observing the influence of parameters change on semi-empirical and empirical tire models requires time-consuming experiments and expensive test equipment. Hence, we use a physical tire model with linearized unstable zone given by equation (11) 29…”

“…where v s is sliding speed and according to Figure 2(b), equals to the difference between circumferential and longitudinal speeds of the wheel. Hence, by combining equations (10) and (13), the slip power loss is obtained by 29…”

“…As tire inflation pressure increases, rolling resistance decreases due to reduction of tire deformation, but slip loss would be increased simultaneously. 28,29 This interdependent influence of change in the inflation pressure on rolling and slip resistances should be evaluated in optimization problem. Experimental studies have shown that using a power function to express the dependency of rolling resistance to inflation pressure is favorably consistent with measurements.…”

“…Nevertheless, experimental study done by Sina et al 28 has shown that tire longitudinal slip also results in a power loss through the driveline. Accordingly, authors in Reference [29] introduced the modified tire resistance, which comprises of rolling resistance and a newly defined term, slip resistance. Since tire side slip during the cornering results in a power loss as well, minimizing the relevant slip loss by optimally adjusting the torque distribution between the wheels improves the efficiency.…”