Design and analysis of a modified power-split continuously variable transmission

Abstract

Design and Analysis of a Modified Power Split Continuously Variable Transmission Andrew J. Fox The continuously variable transmission (CVT) has been considered to be a viable alternative to the conventional stepped ratio transmission because it has the advantages of smooth stepless shifting, simplified design, and a potential for reduced fuel consumption and tailpipe emissions. These benefits have driven all of the major automobile manufacturers to explore different designs of the CVT for the last century. Through this work, the CVT has been developed into a practical alternative to the conventional transmission for vehicles in the lower two thirds of the power spectrum.

Efficiency Evaluation of Continuously Variable Transmissions Including a Planetary Gear Train

“…An important factor in power flow analysis within power split transmissions, called factor of power flow, is adopted to identify the type of power flows [9] (Figures 1 and 2). The type of power flow is conventionally defined by the ratio of the power through the control circuit   cir 5 P P  by the output power (P out ) [10,11].…”

“…In Type I and Type II power flows, certain transmission components are exposed to a power load greater than that of the input load. Distinction between the three power types could be made thanks to the so-called circulating power factor, defined by [9][10][11]…”

“…The variable element in this transmission is responsible for the greatest part of the mechanical losses because it is less efficient than conventional gears [9]. The type of variable element chosen for this particular application was the metal pushing belt CVU because it offers acceptable efficiency values compared to other variable elements [3,5].…”

Torque Converter Operating with Power Splitting Concept

“…Thereafter, the two power portions are combined together with different output characteristic (torque and speed), [6]. Several studies have been carried out to illustrate its merits [7][8][9][10][11][12]. Vorecon is a well-known torque converter operated with such concept admitted by Voith company representing an example of a commercial application [13].…”

Advanced Power Transmission System

“…Thereafter, the two power portions are combined together with different output characteristic (Torque and speed) [7] . Vast studies have been carried out to illustrate its merits [7][8][9][10][11][12][13][14] . Continuous variable transmission and infinity variable transmission are wide application scale of this concept in vehicles.…”