Experimental verification of small diameter rollers utilization in construction of roller test stand in evaluation of energy loss due to rolling resistance

Abstract

The vehicle‘s tire rolling resistance in road traffic plays a significant role mainly in the fields of fuel consumption and produced harmful emissions. It also plays a significant role in measuring on the roller test stands. An inspection measurement has a task of revealing such vehicles in traffic which have a negative influence on the environment and the traffic safety. It is necessary to develop constantly and complement the inspection tests so that it would be possible to keep pace with vehicle producers. Vehicles have been equipped with a number of electronic systems with a direct impact on the traffic safety and ecology at the present. The widely known DieselGate affair has shown the need for roller test stands not only for homologation measurements, but also to satisfy the inspection measurement needs. For the inspection tests, the overground roller testers with smaller rollers and therefore also with lower investment costs, seem to be very advantageous. The tire rolling resistance on the small diameter rollers (approximately 100 mm) will have considerable influence on the measurement (usually, the rollers with the diameter of 180–250 mm are used). The paper is focused on the tire rolling resistance (energy losses) analysis, considering the variously sized rollers (90–400 mm), vertical loads (2000–4000 N), speeds (10–70 km/h) and inflation pressures (1.9–3.2 bar). When using a small summer tire with the size of 165/70 R13 the resulting values showed that the tire inflation pressure have lower influence than 5% on the smaller rollers, vertical load showed similar effect. On the contrary, the roller size showed a significant influence. When using the 90 mm rollers, the energy loss attributable to rolling resistance doubled in comparison with the 400 mm rollers. In general, however, the small diameter of the rollers seems appropriate for a short-time inspection test cycles, which are currently modified in order to recognize vehicles in bad technical condition, namely at measuring of emissions production and braking effect.