Performance Of Continuously Variable Transmission Research Articles

To Optimise the Performance of Electric Powertrain by Tuning the CVT

There is desperate need to find an alternate power source to run the vehicles. This reasons leads to work on electric vehicles. In India, it has been noticed major part of urban air pollution is caused by auto rickshaw emissions as they are not maintained properly. So switching from conventional rickshaw to electric will significantly reduce this problem in urban areas. Continuously variable transmission (CVT) transfers power uninterrupted due to its infinite gear ratios. Moreover, it allows the motor to run at its optimum speed which ultimately reduces the current consumption. CVT available in current market is design to work efficiently with internal combustion engines. This CVT can be made compatible with pure electric power train by CVT tuning. This paper aims to study and analyses the effect on performance of CVT by varying the mass of flyweights. The driver and driven pulley RPM are measured using DAQ system. This data is then use to obtain gear ratio. The iterations are performed using two different mass of flyweights. The gear ratio verses pulley rpm graphs are compared. The result infers that as the flyweight mass is increase the engagement rpm decreases and up-shift rate increases. This enhances performance of CVT.

Lightweight electric vehicle with a CVT gearbox and performance tests

In this study, an electric go cart vehicle was designed and its prototype was built. Through use of a CVT (Continuously Variable Transmission) gearbox, the performance of the vehicle was attempted to be increased. When the transmission free (transmission rate fixed at 1) vehicle and the vehicle with CVT transmission were compared with regard to range and performance, the automatic transmission box with constantly changing rates was proven to increase the range and performance of the vehicle immensely, and various other benefits were seen as a result of the tests performed.

Investigation of the Operational Behaviour of Wide V-Belts in CVT Applications

This paper examines wide V-belt operational behaviour operated continuously variable transmission (CVT). Important for the prediction of an optimum driving performance it is necessary to understand the motion principle of the belt in the pulley during operation. First, the design of a test rig is described, where both the driving and driven pulleys are programmable controlled, giving details of the capabilities. Second, to describe the efficiency of the drive, losses due to slip and the mechanical properties of belt material are determined. To conduct the mechanical properties of the steel-reinforced belt an experimental method is introduced. Finally, emphasis is placed on determination of circumferential motion of the belt due to various drive operating parameters. Through the study, it is found that mechanical wear at both sides of the V-belt caused by the belt’s motion is the most serious problem that affects the CVT performance.

Design Improvement through Reliability Analysis of Belt-Type CVT Systems for Scooters

The purpose of the present study is to carry out failure analysis of a scooter’s continuously variable transmission (CVT) system that is considered to be one of the key components of the scooter. In the study, several reliability analytical tools such as failure mode, effect and criticality analysis (FMECA) and fault tree analysis (FTA) are used to identify possible failure modes of the CVT system and its subsystems. The failure effects of components on the CVT system are emphasized in particular. Aside from the qualitative evaluation, simulation algorithms are developed to examine the performance of the CVT system and assess the reliability of the belt. Through the study, it is found that mechanical wear at both sides of the V-belt is the most serious problem that affects the CVT performance. The sliding collar of the driven pulley is another component that has to be observed carefully. Some design improvements are pointed out at the end of the paper.

Transient dynamics of metal V-belt CVT: Effects of band pack slip and friction characteristic

A continuously variable transmission (CVT) offers a continuum of gear ratios between desired limits. The present research reports a detailed continuous one-dimensional transient-dynamic model of a metal V-belt CVT that accurately captures the various transient dynamic interactions occurring in the CVT system. Since a sundry of models mentioned in the literature ignore the influence of slip between the band pack and the belt element on the CVT performance, a unique model is outlined in this paper that aptly captures the slip-dynamics between the band-pack and the belt element. A considerable amount of effort in this paper is also dedicated towards modeling the inertial coupling between the belt and the pulley and studying its influence on the dynamic performance of a CVT. A metal V-belt CVT falls under the category of friction-limited drives as its performance and torque capacity rely significantly on the friction characteristic of the contact patch between the belt element and the pulley. A unique friction characteristic is also embedded into the CVT model to capture the effects of friction under dry and lubricated contact conditions. Simple trigonometric functions are introduced to capture the effects of pulley flexibility on the thrust ratio and slip behavior of the CVT. The results discuss the influence of band pack slip, friction characteristic, and pulley flexibility on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a metal V-belt CVT drive.

Simultaneous Control for Optimization of Fuel Consumption and Sensitivity of an Accelerator Pedal by Engine-CVT Consolidated Control.

When a continuously variable transmission (CVT) equipped with an automobile and a throttle valve angle and a CVT gear ratio were simultaneously controlled by a computer using a drive by wire (DBW) algorithm, an engine operating condition and a vehicle driving condition could be controlled independently and voluntarily. In this paper, the DBW algorithm was developed to accomplish both fuel economy and dynamics of the vehicle (hereinafter called of accelerator pedal). An experiment and an analysis focussing on the required CVT performance were carried out using the algorithm. As a result, the DBW algorithm was found to accomplish both fuel economy and sensitivity of accelerator pedal, and good agreement was obtained between analytical and experimental results.