A Validated Modular Model for Hydraulic Actuation in a Pushbelt Continuously Variable Transmission

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Stan van der Meulen ◽  
Rokus van Iperen ◽  
Bram de Jager ◽  
Frans Veldpaus ◽  
Francis van der Sluis ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
First Principles ◽  
Closed Loop ◽  
Low Complexity ◽  
High Accuracy ◽  
Continuously Variable Transmission ◽  
Design Parameters ◽  
Actuation System ◽  
Modular Model ◽  
Variable Transmission

A reduction in the fuel consumption of a passenger car with a pushbelt continuously variable transmission (CVT) can be established via optimization of the hydraulic actuation system. This requires a model of the dynamic characteristics with low complexity and high accuracy, e.g., for closed-loop control design, for closed-loop simulation, and for optimization of design parameters. The hydraulic actuation system includes a large number of hydraulic components and a model of the dynamic characteristics is scarce, which is caused by the complexity, the nonlinearity, and the necessity of a large number of physical parameters that are uncertain or unknown. In this paper, a modular model for the hydraulic actuation system on the basis of first principles is constructed and validated, which is characterized by a relatively low complexity and a reasonably high accuracy. A modular approach is pursued with respect to the first principles models of the hydraulic components, i.e., a hydraulic pump, spool valves, proportional solenoid valves, channels, and hydraulic cylinders, which reduces complexity and improves transparency. The model parameters are either directly provided, directly measured, or identified. The model of the hydraulic actuation system is composed of the models of the hydraulic components and is experimentally validated by means of measurements that are obtained from a production pushbelt CVT. Several experiment types are considered. The correspondence between the measured and simulated responses is fairly good.

Investigation of Compliant Ortho-Planar Springs for Rotational Applications

2006 ◽  
Author(s):  
Nathan O. Rasmussen ◽  
Robert H. Todd ◽  
Larry L. Howell ◽  
Spencer P. Magleby
Keyword(s):  
Continuously Variable Transmission ◽  
Direct Result ◽  
Design Parameters ◽  
Stress Concentrations ◽  
Lateral Instability ◽  
Lateral Buckling ◽  
Primary Motivation ◽  
Variable Transmission

This paper explores the feasibility of using compliant-ortho-planar springs (COPS) for rotational applications. The primary motivation is the application of COPS to a rubber v-belt continuously variable transmission (CVT). Although stresses and stress concentrations are important for the design of a COPS, this paper will focus on the behavior of a COPS resulting specifically from its rotation. This paper focuses on issues related to stress stiffening and lateral instability. Both phenomena are a direct result of the inertial loads a COPS would experience in a rotating environment. The results show how stress stiffening and lateral buckling are influenced by design parameters. Conclusions and recommendations for further research are presented.

Dynamics Analysis and Control of a Holonomic Vehicle With a Continuously Variable Transmission

2000 ◽  
Vol 124 (1) ◽  
pp. 118-126 ◽  
Author(s):  
Karim A. Tahboub ◽  
Harry H. Asada
Keyword(s):  
Dynamic Characteristics ◽  
Impedance Matching ◽  
Gear Ratio ◽  
Continuously Variable Transmission ◽  
Friction Compensation ◽  
Vehicle Stability ◽  
Dynamics Analysis ◽  
Dc Motors ◽  
Variable Transmission ◽  
And Control

This paper presents kinematic and dynamic analysis of a holonomic vehicle with continuously-variable transmission. Four ball wheels, independently actuated by DC motors, enable for moving the vehicle in any direction within the plane and rotating it around its center. The angle between the two beams holding the balls can be changed to alter the gear ratio and other dynamic characteristics of the vehicle. This feature is exploited in augmenting the vehicle stability, optimizing output power, selecting an appropriate gear ratio, and in impedance matching. A simple adaptive friction-compensation-based controller is proposed to handle the complex friction properties.

FRICTIONAL PROBLEMS IN CONTINUOUSLY VARIABLE TRANSMISSION BELT DRIVES

Tribologia ◽  
2017 ◽  
pp. 93-100 ◽  
Author(s):  
Wojciech SZCZYPIŃSKI-SALA ◽  
Krzysztof DOBAJ ◽  
Adam KOT
Keyword(s):  
High Performance ◽  
Angular Speed ◽  
Continuously Variable Transmission ◽  
Design Parameters ◽  
Belt Drive ◽  
Power Losses ◽  
Belt Drives ◽  
Variable Transmission ◽  
Drive Systems ◽  
The Impact

The article describes the results of the research carried out on the evaluation of the influence of friction pairs (rubber belt – belt pulley in belt drive) on the ability to transmit power. In order to determine the characteristics of the belt drive operation, measurements were made on a real belt drive from the drive train of a light two-wheeled vehicle. The measurement was carried out in conditions of changes in the dynamic load. The measurements of the belt slip on the belt pulley within the whole range of the changes of gear ratios and angular speed of the engine were made. During the tests, belts made from various rubber mixtures were compared. The values of the friction coefficients between the surface of belts and the belt pulley were measured. Model analyses of the impact of belt slip on the wheel related to the temperature of Belt drive elements were also made. Generally, one can ascertain that, in belt drive systems, power losses are a combination of speed losses and torque losses. The increase in the efficiency of belt drives is possible by decreasing power losses. It is possible to obtain the high performance of continuously variable transmission belt drives with a V- belt solely with the proper choice of the design parameters, which is possible only after the exact recognition of the operational characteristics unique to this class of belt drive systems.

Indirect Clamping Force Measurement Method Using Current Sensor for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission System

2014 ◽  
Vol 663 ◽  
pp. 238-242
Author(s):  
Bambang Supriyo ◽  
Kamarul Baharin Tawi ◽  
Mohd Salman Che Kob ◽  
Izhariizmi Mazali ◽  
Yusrina Zainal Abidin
Keyword(s):  
Positive Impact ◽  
Force Sensor ◽  
Dc Motor ◽  
Continuously Variable Transmission ◽  
Current Sensor ◽  
Clamping Force ◽  
Primary Input ◽  
Motor Current ◽  
Actuation System ◽  
Variable Transmission

This paper introduces an electro-mechanical dual acting pulley continuously variable transmission (EMDAP CVT) system and presents a method of measuring belt-pulley clamping force indirectly using a DC motor current sensor. The EMDAP CVT mainly consists of two movable primary (input) and secondary (output) pulley sheaves connected by metal pushing V-belt. Two DC motor’s actuation systems adjust the CVT ratio. Additionally, the secondary actuation system controls belt-pulley clamping force by adjusting the flatness of the spring discs placed at the back of each secondary pulley sheave to keep the belt tight and prevent belt slip. Ideally, a force sensor is used to measure the belt-pulley clamping force however the use of force sensor inside transmission gearbox is not feasible due to high temperature and oily environment. A viable solution for indirectly measuring the clamping force using current sensor for DC motor is proposed. Since the DC motor actuates the movable pulleys to clamp the belt, the relationship between the DC motor current and belt-pulley clamping force can then be investigated experimentally. The results will give positive impact on precisely controlling belt-pulley clamping force of EMDAP CVT using current sensor which is relatively simpler and less expensive than force sensor.

Power-Transfer Capacity of a Geared-Neutral Transmission

2007 ◽  
Author(s):  
Burak Gecim ◽  
Neil Anderson ◽  
Jeffrey Wehking
Keyword(s):  
Continuously Variable Transmission ◽  
Maximum Power ◽  
Contact Temperature ◽  
Design Parameters ◽  
Power Transfer ◽  
Power Capacity ◽  
Variable Transmission ◽  
Capacity Estimates ◽  
Ratio Range

Geared-neutral Continuously Variable Transmission (CVT) designs offer various kinematic advantages including a wide ratio range, and elimination of starting devices. However, they suffer from power re-circulation through the Continuously Variable Unit (CVU), which reduces the overall CVT efficiency and increases the CVU contact temperatures. This, in turn, limits the CVT power rating. In this study, the CVU and the CVT design parameters are optimized simultaneously to yield the highest power capacity. The CVU power capacity estimates are based on an instantaneous CVU-contact-temperature of 180°C. It is shown that a CVU design that yields the maximum power capacity is different from a design that yields the highest CVU efficiency.

The Research of Axial Deflection and Generatrix of Metal Belt CVT

2009 ◽  
Author(s):  
Wu Zhang ◽  
Kai Liu ◽  
Chun-Guo Zhou ◽  
Yi-Duo Wei ◽  
Ning-Qiang Wu
Keyword(s):  
Numerical Methods ◽  
Life Span ◽  
Continuously Variable Transmission ◽  
The State ◽  
Design Parameters ◽  
Actual Situation ◽  
Contact Strength ◽  
Working Process ◽  
Calculating Method ◽  
Variable Transmission

To reduce the metal belt’s axial deflection of the metal belt continuously variable transmission (CVT) during the working process, the value of the axial deflection has been calculated by using numerical methods. The precision of two methods to calculate the deflection has been compared. A calculating method closer to the actual situation has been attained. According to the principle of conjugate curves, and with the involute generatrix of the metal belt as example, a solution to the generatrix of the pulley conjugated with it is obtained, and the relation between the pullys generatrix curvature and the pulleys generatrix contact strength is achieved. By changing the metal belt value of the design parameters, the state subject to force between the pulley and the metal belt can be improved. So as to ensure the whole metal belt level transmit in the process of speed changes. Theoretically, the axial deflection can be eliminated completely, and the life span of the metal belt and the reliability of the transmission, as well as the performance of the metal belt CVT can be greatly improved, so as to provide the references for the CVT design.

APPLICATION OF DISC SPRING IN CLAMPING FORCE MECHANISM FOR ELECTRO-MECHANICAL CONTINUOUSLY VARIABLE TRANSMISSION

2015 ◽  
Vol 77 (22) ◽  
Author(s):  
Izhari Izmi Mazali ◽  
Kamarul Baharin Tawi ◽  
Bambang Supriyo ◽  
Mohd Sabri Che Kob ◽  
Nurulakmar Abu Husain ◽  
...  
Keyword(s):  
High Power ◽  
Fuel Economy ◽  
Continuously Variable Transmission ◽  
Clamping Force ◽  
Actuation System ◽  
Variable Transmission ◽  
High Power Consumption ◽  
Force Mechanism ◽  
Compact Design ◽  
Disc Spring

Pulley-based continuously variable transmission (CVT) with metal pushing V-belt (V-belt) offers tremendous potentials in the fuel economy of the car due to its wide and continuous ratio coverage. Nevertheless, the existing pulley-based CVTs in automotive markets use electro-hydro-mechanical (EHM) actuation system to vary its ratio and to provide sufficient clamping force on the V-belt. This, unfortunately, leads to a significant high power consumption from the engine of the car which eventually worsens the car’s fuel economy. To address this issue, researchers introduce electro-mechanical CVT (EM CVT) in which the application of the EHM actuation system is replaced by an electro-mechanical (EM) actuation system. This paper discusses the application of disc spring in clamping force mechanism of EM CVT. The selected disc spring is analyzed and evaluated to prove its workability for CVT’s application. The analysis results indicate that the application of disc spring in clamping force mechanism of EM CVT is possible and it also offers some benefits particularly in term of its compact design.  

Modeling and Simulation of Continuously Variable Transmission (CVT) Hydraulic System

2012 ◽  
Vol 622-623 ◽  
pp. 1221-1225
Author(s):  
Ma Shu Yuan ◽  
Bdran Sameh ◽  
Saifullah Samo
Keyword(s):  
Control System ◽  
Modeling And Simulation ◽  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Hydraulic System ◽  
Continuously Variable Transmission ◽  
Hydraulic Control ◽  
Variable Transmission ◽  
Hydraulic Control System

As most of today’s a continuously variable transmission (CVT) adopt an electro-hydraulic control system, the role of electronically controlled solenoid valves play an important stature. This paper presents a dynamic modeling and simulation of CVT hydraulic system using Matlab-simulink package and analyzes the dynamic characteristics of the CVT hydraulic system in frequency domain.

Pulleys' Axial Movement Mechanism for Electro-Mechanical Continuously Variable Transmission

2014 ◽  
Vol 663 ◽  
pp. 185-192 ◽  
Author(s):  
Kamarul Baharin Tawi ◽  
Izhari Izmi Mazali ◽  
Bambang Supriyo ◽  
Nurulakmar Abu Husain ◽  
Mohd Salman Che Kob ◽  
...  
Keyword(s):  
Continuously Variable Transmission ◽  
Hydraulic Pressure ◽  
Actuation System ◽  
Powertrain System ◽  
Axial Movement ◽  
Variable Transmission ◽  
Movement Mechanism ◽  
Potential Benefits ◽  
High Power Consumption ◽  
Axially Moving

Pulley-based continuously variable transmission (CVT) with Metal Pushing V-belt (V-belt) is a type of automotive transmission that is widely applied currently by many car manufacturers worldwide. Unlike the conventional automotive transmissions, in a pulley-based CVT with V-belt, the transmission ratio (CVT ratio) is changed continuously without the use of discrete gears. Instead, the CVT ratio is varied through the simultaneous axial movement of the primary pulley and the secondary pulley. By axially moving both pulleys simultaneously, the radius of the V-belt on both pulleys will be changed accordingly, resulting in the change of the CVT ratio. The existing pulley-based CVTs in the market use electro-hydro-mechanical (EHM) actuation system to change and to maintain the desired CVT ratio through the hydraulic pressure. However, the application of EHM actuation system leads to some disadvantages, particularly in term of the high power consumption from the engine needed to maintain the desired CVT ratio. This reduces the efficiency of the powertrain system, which eventually increases the fuel consumption of the vehicles. In addition to that, the existing pulley-based CVTs also use single acting pulley mechanism to axially move the pulleys for changing the CVT ratio. Therefore, the issue of V-belt's misalignment, which shortens the lifespan of the V-belt, is inevitable here. In this paper, the pulleys' axial movement mechanism that uses electro-mechanical (EM) actuation system is proposed. Consequently, the working principle of the proposal is described and its potential benefits are discussed.

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