2021 Volume 52 Issue 4 Pages 917-922
In the wind tunnel method determined in WLTP, a correction formula is set up to correct rolling resistance measured on a drum to an equivalent for a flat surface,. The coefficient used in the correction formula is established by agreement between the automobile maker and the authorities concerned. A detailed value is not specified in regulations. In addition, the values suggested as default values have deviated from actual vehicle figures from the theoretical viewpoint of the tires. Specifically, c1 was estimated from the contribution ratio of tire in the total rolling resistance. Further, c2 was estimated from the transformation ratio of the dynamic load radius. Moreover, the drive energy corrected using the estimated coefficient was compared with the drive energy calculated from actual running resistance tests. The results confirmed that both values were almost the same.
