論文ID: 19-00098
Vehicles with a metal belt-type continuously variable transmission(CVT) that can run under optimal engine fuel consumption conditions have been popular. However, the CVT unit itself can improve in terms of the efficiency. This is possible as the clamping force of the ordinary CVT is much greater than the minimum force required to prevent a large belt slip, which results in excessive friction loss in the belt. The clamping force should be reduced to approximately equal the maximum belt friction force to prevent a large belt slip and improve the efficiency of the CVT unit. However, the belt friction force varies depending on its operating condition and age. Thus, an generating state of the maximum friction force should be detected in each running condition. In this study, we investigate the following three detection methods for the generating state. 1) detection using the speed ratio as a conventional method, 2) a detection method wherein the gradient of the belt friction force on the slip velocity between the pulley and belt is nearly 0 near the belt μ, and 3) a detection method wherein a correlation value between the input and output rotational speeds of the CVT decreases below 1.0. We have described the methods used in this study in detail, and discussed their performance and computational efficiency.
