scholarly journals Continuously Variable Transmissions - outline

2018 ◽  
Vol 19 (6) ◽  
pp. 447-451
Author(s):  
Jarosław Goszczak ◽  
Bartosz Radzymiński
Keyword(s):  
Work Conditions ◽  
Continuously Variable Transmission ◽  
Manual Transmission ◽  
Production Data ◽  
Passenger Cars ◽  
The World ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Ratio Change ◽  
Different Parts

Paper concerned the Continuously Variable Transmission (CVT). The comparison of the engine’s work conditions with conventional manual transmission and CVT’s is presented. Also, a short historical track is included. Furthermore, a production data with the forecast is presented for different parts of the World. Various current solutions of continuous ratio change are mentioned with the more detailed description of the most popular design used in passenger cars. Technological challenges and possibilities of further transmission improvement are included.

scholarly journals Preliminary synthesis of algorithms for automatic control of automobile continuously variable transmissions with flexible links

2020 ◽  
Vol 1 (4) ◽  
pp. 25-37
Author(s):  
A.E. Yesakov ◽  
◽  
A.V. Kretov ◽  
P.A. Krasavin ◽  
◽  
...  
Keyword(s):  
Automatic Control ◽  
Direct Consequence ◽  
Continuously Variable Transmission ◽  
Factors Affecting ◽  
Flexible Links ◽  
Automatic Control Systems ◽  
High Durability ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
The One

Variators of different operating principles and designs are of interest as components of automatic transmissions for ground transport and traction machines. At the same time, one of the most popular types of variators are the variators built on the basis of continuously variable transmissions with flexible links. The main reasons for the use of such variators in the transmissions of a number of modern passenger vehicles are, on the one hand, the emergence of flexible link designs with high durability, and, on the other hand, the widespread introduction of programmable electronic devices into automatic control systems for continuously variable transmissions. A direct consequence of the latter circumstance was the need for in-depth research aimed at synthesizing such control algorithms that would make it possible to fully use the advantages inherent in continuously variable transmissions with flexible links and minimize the operational consequences of their shortcomings. This paper makes an attempt to solve the problem of synthesizing the algorithm in a preliminary form, based on the goal of providing the vehicle with the best traction and speed properties. The presence of such an attempt will allow, having set the main parameters of a continuously variable transmission for some reason, to develop the hardware of the automatic control system. In turn, this will make it possible to synthesize a refined algorithm that takes into account the dynamics of the system, errors of meters and signal conversion devices, as well as other factors affecting work pro-cesses. When considering the described problem, various variants of the geometry of the contact surfaces of the continuously variable transmission links were taken into account and the corre-sponding mathematical apparatus were formed. The results of calculations, obtained by computer program that implements these devices, are selectively presented in the materials of the paper.

Limited-slip and torque-vectoring effect of a dual continuously variable transmission

2016 ◽  
Vol 231 (3) ◽  
pp. 372-382 ◽  
Author(s):  
I-Ming Chen ◽  
Yuan-Yao Huang ◽  
Tai-Her Yang ◽  
Tyng Liu
Keyword(s):  
Dynamic Model ◽  
Rear Wheel ◽  
Continuously Variable Transmission ◽  
Transmission System ◽  
Transmission Model ◽  
Differential Model ◽  
Torque Vectoring ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Final Drive

This study investigates the limited-slip and steering characteristics of a dual continuously variable transmission system. The dual continuously variable transmission is a unique final drive system composed of two continuously variable transmissions, with one continuously variable transmission connected to each rear wheel. In this study, a dynamic model of the dual continuously variable transmission system is derived, and models of the conventional final drive systems, i.e. the solid axle and the open differential, are used as benchmarks. In the simulations, the dual continuously variable transmission model, the solid axle model and the open differential model are applied to a vehicle dynamic model for split- μ road tests and a series of steering tests. According to the results of the split- μ road tests, the limited-slip function of a dual continuously variable transmission system is verified. The results of the steering tests show that different torque distributions for the inside wheels and the outside wheels while cornering can be controlled with different gain values of the continuously variable transmissions; for this reason, the application of the dual continuously variable transmission system as a torque-vectoring device is proposed, and a basic setting principle is presented. The results of this study establish a fundamental knowledge for developing the dual continuously variable transmission as an advanced final system for improving the vehicle dynamics.

Power split continuously variable transmission systems with high efficiency

2001 ◽  
Vol 215 (3) ◽  
pp. 357-358 ◽  
Author(s):  
G. Mantriota
Keyword(s):  
Power Flow ◽  
High Efficiency ◽  
Continuously Variable Transmission ◽  
Operating Conditions ◽  
Kinetic Characteristics ◽  
The Past ◽  
Power Split ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Functional Solution

Continuously variable transmissions (CVTs) have developed notably in different applications over the past years. This is especially true in the automobile field because of advantages in terms of car handling and efficiency on urban roads. In this work an original functional solution of a power split CVT system is described. The proposed solution allows the generation of a power flow without recirculation. Kinetic characteristics of single-component devices are obtained and the power split CVT system's efficiency is determined by considering how the efficiency of the component devices changes as a function of operating conditions. The advantages for the power split CVT system are therefore shown in terms of power and efficiency in comparison with the single CVT.

scholarly journals Transmission characteristics and phase number optimization on the transmission mechanism of rod gear pulse continuously variable transmission

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775196
Author(s):  
Suifan Chen ◽  
Zhifeng Dong
Keyword(s):  
Single Phase ◽  
Basic Structure ◽  
Continuously Variable Transmission ◽  
Transmission Characteristics ◽  
Continuously Variable Transmissions ◽  
The Matrix ◽  
Variable Transmission ◽  
Working Principle ◽  
Eccentric Wheel ◽  
Selection Of

In order to solve the oversize problem of continuously variable transmission, a rod gear pulse continuously variable transmission is designed. The kinematic mathematical models of key components are established by the matrix method and are simulated by MATLAB in a single phase, based on the analysis of basic structure and working principle of transmission. Also, the length requirements of each rod are studied, and the effect of three adjustment manners on the output-speed is simulated in the single phase. Furthermore, the simulations of the movement law of annular gear are achieved on two conditions of both different phases and different eccentricities on 8-phase. The results show that the manner of adjusting the eccentricity of eccentric wheel is the preferential selection of out-speed regulating method, and 8-phase is an optimal phase of transmission; meanwhile, for the rod gear pulse continuously variable transmission, the variable range of transmission ratio is wider and the pulsation rate is far less than the other traditional continuously variable transmissions.

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.

Designing a Hydraulic Continously Variable-Transmission (CVT) for Retrofitting a Rear-Wheel Drive Automobile

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Noah D. Manring ◽  
Taha S. Al-Ghrairi ◽  
Sean D. Vermillion
Keyword(s):  
Vehicle Dynamics ◽  
Engine Speed ◽  
Rear Wheel ◽  
Continuously Variable Transmission ◽  
Hydraulic Pump ◽  
Wheel Drive ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Primary Advantage ◽  
Rear Wheel Drive

This research shows that an existing rear-wheel drive vehicle may be easily retrofitted with a continuously variable-transmission for the purposes of reducing the overall fuel consumption of the automobile. The retrofit-ability of this transmission is the primary advantage that it exhibits over other continuously variable-transmissions. By retrofitting this vehicle with the transmission components that are shown in this paper, the existing vehicle transmission continues to be used with the exception of the driveshaft which is replaced by the hydraulic continuously variable-transmission itself. Using a standard model for the vehicle dynamics, this paper presents a detailed analysis for the speed ratios of all gears, and shows how to specify the size of the hydraulic pump and motor to insure a safe pressure level of operation. To illustrate the usefulness of this method, an actual transmission is designed for the 1997 Ford Ranger, and the range of adjustability for the transmission is evaluated by seeking to hold the engine speed constant for a ramped speed output of the vehicle. In conclusion, this research shows that the design methodology is valid and that only minor errors in engine speed are observed during low ground velocities for the vehicle.

Investigation technique for dynamics of operative mechanical continuously variable transmission with a resilient member and free-wheel mechanism

2020 ◽  
pp. 28-34
Author(s):  
V. B. Derzhansky ◽  
◽  
S. V. Cherepanov ◽  
A. A. Volkov ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Lagrange Equation ◽  
Continuously Variable Transmission ◽  
Experimental Investigations ◽  
Dynamic Force ◽  
Resonant Modes ◽  
Investigation Technique ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Working Out

Mechanical continuously variable transmissions have high potential for torque conversion, are capable of providing significant technical and economic advantages when used in shafts of technological and other machines, this making investigations in this area to be pertinent. This paper represents a mechanical and mathematical technique, which enables to do research of dynamic processes, that occur in functioning of mechanical continuously variable transmission with a resilient member and free-wheel mechanism, making it possible to transmit torque to a driven shaft only in the same direction. The objective of this paper is to work out a mathematical model of the mechanical system, which determines dynamic force of transmission elements. Computational model of transmission is shown, in obedience to which there was built a mathematical model based on Lagrange equation of second kind with undetermined multipliers. A set of assumptions was made on working out the dynamic system mathematical model. In particular, possibility of excitation of resonant modes in a resilient member was not considered. Moreover, nonlinearity of free-wheel mechanisms was not considered as well as hysteresis losses of energy in on-off use cycle and significant capacity costs in disconnected machinery. In future it is necessary to carry out experimental investigations in order to make transmission dynamics more exact. By the results of simulation modeling regularities were obtained which determine dynamic moments on transmission elements. The results of the investigation may be used for making an output characteristic of transmission, its adaptation with the motor and forecasting of operational features of shafts of different technological equipment.

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