Dynamics of Chain CVT Drives: Effects of Friction Characteristic

2007 ◽  
Author(s):  
Nilabh Srivastava ◽  
Imtiaz U. Haque
Keyword(s):  
Mathematical Models ◽  
Axial Force ◽  
Dynamic Performance ◽  
Continuously Variable Transmission ◽  
Friction Characteristic ◽  
Contact Patch ◽  
Multibody Model ◽  
Variable Transmission ◽  
Torque Capacity ◽  
A Chain

A chain CVT is a type of friction-limited continuously variable transmission that provides a continuum of gear ratios with fewer moving parts. The dynamic performance and torque capacity of a chain CVT drive rely significantly on the friction characteristic of the contact patch between the chain and the pulley. Since the friction characteristic of the contact patch may vary in accordance with the loading and design configurations, it is crucial to study the influence of friction characteristic on the performance of a CVT. Two different mathematical models of friction, which characterize different operating/loading conditions, are embedded into a detailed planar multibody model of chain CVT in order to understand the various friction-induced effects in the system. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction characteristics on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a chain CVT drive.

Transient Dynamics of the Metal V-Belt CVT: Effects of Pulley Flexibility and Friction Characteristic

2006 ◽  
Vol 2 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Nilabh Srivastava ◽  
Imtiaz Haque
Keyword(s):  
Dynamic Performance ◽  
Trigonometric Functions ◽  
Dimensional Model ◽  
Friction Characteristic ◽  
Friction Characteristics ◽  
One Dimensional ◽  
Contact Patch ◽  
Inertial Coupling ◽  
Variable Transmission ◽  
Torque Capacity

A continuously variable transmission (CVT) offers a continuum of gear ratios between desired limits. The present research focuses on developing a continuous one-dimensional model of the metal V-belt CVT in order to understand the influence of pulley flexibility and friction characteristics on its dynamic performance. 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. Since the friction characteristic of the contact patch may vary in accordance with the loading and design configurations, it is important to study the influence of the friction characteristic on the performance of a CVT. Friction between the belt and the pulley sheaves is modeled using different mathematical models which account for varying loading scenarios. Simple trigonometric functions are introduced to capture the effects of pulley deformation on the thrust ratio and slip behavior of the CVT. Moreover, since a number of models mentioned in the literature neglect the inertial coupling between the belt and the pulley, a considerable amount of effort in this paper is dedicated towards modeling the inertial coupling between the belt and the pulley and studying its influence on the dynamic performance of a CVT. The results discuss the influence of friction characteristics and pulley flexibility on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a metal V-belt CVT drive.

Influence of Clearance on the Dynamics of Chain CVT Drives

2006 ◽  
Author(s):  
Nilabh Srivastava ◽  
Yi Miao ◽  
Imtiaz U. Haque
Keyword(s):  
Dynamic Performance ◽  
Suitable Model ◽  
Multibody Model ◽  
System A ◽  
Automotive Transmission ◽  
Chain Link ◽  
Variable Transmission ◽  
Coulomb Approximation ◽  
A Chain ◽  
Chain Links

A continuously variable transmission (CVT) is an emerging automotive transmission technology that offers a continuum of gear ratios between desired limits. The present research focuses on developing models to understand the influence of clearance on the dynamic performance of a chain CVT drive. Clearances may arise in such a CVT during the assembly process or during extensive continual operation of the system, which further leads to wear and failure of the system. A detailed planar multibody model of a chain CVT is developed in order to accurately capture the dynamics characterized by the discrete structure of the chain, which causes polygonal excitations in the system. A suitable model for clearance between the chain links is embedded into this multibody model of the chain CVT. Friction between the chain link and the pulley sheaves is modeled using continuous Coulomb approximation theory. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of clearance parameters on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a chain CVT drive.

scholarly journals Intelligent Multiobjective Slip and Speed Ratio Control of a Novel Dual-Belt Continuously Variable Transmission for Automobiles

2014 ◽  
Vol 2014 ◽  
pp. 1-17
Author(s):  
Zhengchao Xie ◽  
Pak Kin Wong ◽  
Yueqiao Chen ◽  
Ka In Wong
Keyword(s):  
Analytical Model ◽  
Fuzzy Controller ◽  
Transmission Efficiency ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Rule Base ◽  
Passenger Cars ◽  
Variable Transmission ◽  
Torque Capacity ◽  
Low Torque

Van Doorne’s continuously variable transmission (CVT) is the most popular CVT design for automotive transmission, but it is only applicable to low-power passenger cars because of its low torque capacity. To overcome this limitation of traditional single-belt CVT, a novel dual-belt Van Doorne’s CVT (DBVCVT) system, which is applicable to heavy-duty vehicles, has been previously proposed by the authors. This paper, based on the published analytical model and test rig of DBVCVT, further proposes an intelligent multiobjective fuzzy controller for slip and speed ratio control of DBVCVT. The controller aims to safely control the clamping forces of both the primary and the secondary pulleys in order to improve the transmission efficiency, achieve the accurate speed ratio, and avoid the belt slip under different engine loads and vehicle speeds. The slip, speed ratio, and transmission efficiency dynamics of DBVCVT are firstly analyzed and modeled in this paper. With the aid of a flexible objective function, the analytical model, and fuzzy logic, a Pareto rule base for fuzzy controller is developed for multiobjective DBVCVT control. Experimental results show that the proposed controller for slip and speed ratio regulation of DBVCVT is effective and performs well under different user-defined weights.

Dynamic performance simulation of a continuously variable transmission motorcycle for fuzzy autopilot design

1997 ◽  
Vol 211 (6) ◽  
pp. 477-490 ◽  
Author(s):  
C W Hong ◽  
C C Chen
Keyword(s):  
Control Strategy ◽  
Dynamic Performance ◽  
Continuously Variable Transmission ◽  
Performance Simulation ◽  
Cycle Simulation ◽  
Powertrain System ◽  
Variable Transmission ◽  
Parametric Studies ◽  
Rubber Belt ◽  
Strategy Design

This paper describes the modelling technique of a continuously variable transmission (CVT) motorcycle for control strategy design of an autopilot on a driving cycle test bench. The simulation is carried out on a code which is the combination of an engine cycle simulation synthesis, a dynamic CVT driveline algorithm, a chassis dynamometer model and a fuzzy autopilot controller. The autopilot, which is a robot driver, includes a throttle actuator and a brake handle controller. Fundamental fuzzy theories were employed to simulate the control strategy of an experienced driver, also to form a feedback control loop for the simulation. The whole simulation package is capable of predicting the motorcycle performance under dynamic road conditions, such as ECE R40 and USA FTP75 driving patterns. Simulation results of a baseline motorcycle, equipped with a 125 cm3 four-stroke engine plus a rubber belt CVT system, are demonstrated in this paper. Parametric studies are used to design the control strategy of the autopilot as well as to improve the design of the powertrain system of the motorcycle.

Axial Force Test and Modelling of the V-Belt Continuously Variable Transmission for Mopeds

1996 ◽  
Vol 118 (2) ◽  
pp. 266-273 ◽  
Author(s):  
F. Ferrando ◽  
F. Martin ◽  
C. Riba
Keyword(s):  
Axial Force ◽  
Empirical Model ◽  
Test Bench ◽  
Continuously Variable Transmission ◽  
Transmission Ratio ◽  
Torque Transmission ◽  
Variable Transmission

This article discusses the experiments and modelling carried out on a V-belt continuously variable transmission (CVT) of the type that is used in mopeds. Our aim was to characterize the forces which determine how the system functions. A test bench was designed for them to be determined experimentally and a series of tests which cover the variable conditions of speed, torque, transmission ratio and tension of a CVT are carried out. Estimates of the principal existing models are compared and an empirical model for assessing these forces is discussed.

Physics-based modeling of a chain continuously variable transmission

2016 ◽  
Vol 105 ◽  
pp. 397-408 ◽  
Author(s):  
Chengwu Duan ◽  
Kumar Hebbale ◽  
Fengyu Liu ◽  
Jian Yao
Keyword(s):  
Continuously Variable Transmission ◽  
Variable Transmission ◽  
A Chain

Launching Performance Analysis of a Continuously Variable Transmission Vehicle With Different Torsional Couplings

2005 ◽  
Vol 127 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Jungyun Kim
Keyword(s):  
Performance Analysis ◽  
Mathematical Models ◽  
Continuously Variable Transmission ◽  
Simulation Program ◽  
Road Test ◽  
Passenger Cars ◽  
Transient Characteristics ◽  
The Road ◽  
Torsional Coupling ◽  
Variable Transmission

This article describes the launching behaviors of passenger cars equipped with continuously variable transmission (CVT), which have different torsional couplings: a torsion damper and a dual mass flywheel. To reduce the driveline vibration and noise, a torsional coupling is installed in the CVT vehicle, in which the wet type multiplate clutch is used as a start device. In addition, a torsional coupling makes considerable effects on the launching performance of a vehicle. The launching performances, considered here, are the acceleration performance with various throttle positions and the transient characteristics of vehicle creep and throttle tip-in. By using the mathematical models of each driveline component, we developed a simulation program to investigate the launching performance in various launching conditions. In order to verify our simulation program, we performed the road test of a prototype vehicle that has torsion damper as a torsional coupling. Finally, we analyzed and compared the launching performances in two cases of a torsion damper and a dual mass flywheel using the developed simulation program.

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