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1
Willis, Christopher Ryan. "A Kinematic Analysis and Design of a Continuously Variable Transmission." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/79677.
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This thesis describes a method for analyzing and designing a continuously variable transmission (CVT). The analysis process is implemented in a software package that can be used to tune a CVT for a given application. The analysis is accomplished through the use of kinematic principles as well as equations developed from basic energy balances. Although the theory developed can be applied to any CVT, this thesis focuses on a case study using the Team Industries brand CVT applied to the Virginia Tech Mini Baja Team. The work was motivated by the team's need to have a reliable and inexpensive method for CVT tuning. Previous approaches to CVT tuning were strictly empirical and involved mechanical component replacement in a slow and expensive trialand- error optimization loop. The tuning software is intended to be a first step in the process of properly tuning a CVT for a specific application and not a complete replacement for the empirical methods employed previously.Master of Science
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Bell, Colin Alexander. "Constant power-continuously variable transmission (CP-CVT) : optimisation and simulation." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6279.
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A novel continuously variable transmission has previously been designed that is capable of addressing a number of concerns within the automotive industry such as reduced emissions. At the commencement of this research, the design was in the early stages of development and little attempt had been previously made to optimise the design to meet specific measurable targets. This thesis utilises and modifies several design approaches to take the design from the concept stage to a usable product. Several optimisation techniques are adapted and created to analyse the CVT from both a design and tribological prospective. A specially designed optimisation algorithm has been created that is capable of quickly improving each critical component dimension in parallel to fulfil multiple objectives. This algorithm can be easily adapted for alternative applications and objectives. The validity of the optimised design is demonstrated through a simulation-tool that has been created in order to model the behaviour of the CVT in a real automotive environment using multiple fundamental theories and models including tire friction and traction behaviour. This powerful simulation tool is capable of predicting transmission and vehicular behaviour, and demonstrates a very good correlation with real-world data. A design critique is then performed that assesses the current state of the CVT design, and looks to address some of the concerns that have been found through the various methods used. A specific prototype design is also presented, based on the optimisation techniques developed, although the actual creation of a prototype is not presented here. Additional complementary research looks at the accuracy of the tire friction models through the use of a specially design tire friction test rig. Furthermore, a monitoring system is proposed for this particular CVT design (and similar) that is capable of continuously checking the contact film thickness between adjacent elements to ensure that there is sufficient lubricant to avoid metal-on-metal contact. The system, which is based around capacitance, requires the knowledge of the behaviour of the lubricant’s permittivity at increased pressure. This behaviour is studied through the use of a specially-designed experimental test rig.
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Gibbs, John H. "Actuated Continuously Variable Transmission for Small Vehicles." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1238819759.
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Andersen, Brian S. "An Investigation of a Positive Engagement, Continuously Variable Transmission." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1878.pdf.
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Micklem, J. D. "The investigation and modelling of the steel compression V-belt continuously variable transmission." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359731.
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Cyders, Timothy J. "Analysis and Experimental Comparison of Models of a New Form of Continuously Variable Transmission." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1354807440.
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Guvey, Serkan. "Dynamic Simulation And Performance Optimization Of A Car With Continuously Variable Transmission." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/1095322/index.pdf.
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The continuously variable transmission (CVT), which has been in use in some of
the vehicles in the market today, presents the possibility of decoupling the engine
speed and the vehicle speed. By this way, it is now possible to operate the engine
at its maximum efficient or performance point and fix it at that operating point
without losing from the vehicle speed. Instead of using gears, which are the main
transmission elements of conventional transmission, CVT uses two pulleys and a
belt. By changing the pulley diameters, a continuously variable transmission ratio
is obtained. Besides all its advantages, it has some big drawbacks like low
efficiency, torque transmission ability and limited speed range. With developing
technology, however, new solutions are developed to eliminate these drawbacks.
In this study simulation models for the performance and fuel consumption
of different types and arrangements of continuously variable transmission (CVT)
systems are developed. Vehicles, which are equipped with two different
arrangements of CVT and an automatic transmission, are modelled by using
Matlab’
s simulation toolbox Simulink. By defining the required operating points for better acceleration performance and fuel consumption, and operating the engine at these points, performance optimization is satisfied. These transmissions are compared with each other according to their &
#8216
0-100 kph&
#8217
acceleration performances, maximum speeds, required time to travel 1000 m. and fuel consumptions for European driving cycles ECE and EUDC. These comparisons show that CVT systems are superior to automatic transmission, according to their acceleration and fuel consumption performances. CVTs also provide smoother driving, while they can eliminate jerks at gear shifting points.
8
Randall, Austin B. "Investigation of a Planetary Differential for Use as a Continuously Variable Transmission." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3311.
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With gas prices on the rise, the demand for high-mileage and low pollution vehicles has taken on an unprecedented role in our society. The production and implementation of electric and hybrid-electric vehicles has recently been a large focus of all major automobile manufacturers. Although these new vehicles have begun to solve much of the expensive fuel consumption and air pollution problems that our economy faces, the initial cost of these vehicles has proven to still be too expensive to capture a significant portion of the market. The further advancement of this technology must not only continue to focus on better fuel efficient and decreased pollution producing vehicles, but also decrease the cost of these vehicles to make them more available and enticing to the general public. Results from this research include one potential solution to reduce the cost of electric and hybrid-electric vehicles. Previous research performed in this area has led to the investigation and bench-top testing of a special type of mechanical system known as a Planetary Differential (PD). An exploration of the functionality of this system has shown that the PD can simplify expensive and complex electronic control systems for electric and hybrid-electric vehicles, thus reducing the cost to the consumer. In this study, fundamental speed, torque and power relationships for the PD were developed and tested under various loading conditions. Advantages and disadvantages of the PD, as compared to other similar mechanical systems, are identified and outlined. Recommendations for future work and implementation of the PD in electric and/or hybrid-electric vehicles are presented herein.
9
Alkan, Deniz. "Investigating CVT as a Transmission System Option for Wind Turbines." Thesis, KTH, Energiteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121187.
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In this study, an innovative solution is examined for transmission problems and frequency control for wind Turbines. Power electronics and the gear boxes are the parts which are responsible of a significant amount of failures and they are increasing the operation and maintenance cost of wind turbines. Continuously transmission (CVT) systems are investigated as an alternative for conventional gear box technologies for wind turbines in terms of frequency control and power production efficiency. Even though, it has being used in the car industry and is proven to be efficient, there are very limited amount of studies on the CVT implementation on wind turbines. Therefore, this study has also an assertion on being a useful mechanical analyse on that topic. After observing several different types of possibly suitable CVT systems for wind turbines; a blade element momentum code is written in order to calculate the torque, rotational speed and power production values of a wind turbine by using aerodynamic blade properties. Following to this, a dynamic model is created by using the values founded by the help of the blade element momentum theory code, for the wind turbine drive train both including and excluding the CVT system. Comparison of these two dynamic models is done, and possible advantages and disadvantages of using CVT systems for wind turbines are highlighted. The wind speed values, which are simulated according to measured wind speed data, are used in order to create the dynamic models, and Matlab is chosen as the software environment for modelling and calculation processes. Promising results are taken out of the simulations for both in terms of energy efficiency and frequency control. The wind turbine model, which is using the CVT system, is observed to have slightly higher energy production and more importantly, no need for power electronics for frequency control. As an outcome of this study, it is possible to say that the CVT system is a candidate of being a research topic for future developments of the wind turbine technology.
10
Patrão, Hernâni Martins. "Modelação de variadores contínuos de relação de transmissão." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/9713.
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Dissertação para obtenção do Grau de Mestre em
Engenharia MecânicaO crescente mercado das transmissões de variável continua tem como exigência fulcral uma caracterização aprofundada de todos os seus aspectos funcionais conhecidos e constantemente sejam actualizados. Existem inúmeros tipos de transmissões deste tipo sendo que se optou pela modelagem do sistema de polias de diâmetro variável tendo como meio de ligação uma correia. Tendo sempre a noção de que as transmissões são dos elementos mais utilizados em sistemas de transmissão de força como meio de desmultiplicar o movimento de entrada em relação ao de saída, sendo então que o modelo terá de incluir as características de saída do motor, binário (torque) e rotação e todos os elementos utilizados numa transmissão CVT, cujo objectivo inicial é chegar a um modelo matemático para determinar o rendimento funcional. Ter-se-á de então proceder a uma análise do comportamento dinâmico da transmissão, para tal apresentando-se equações de funcionamento que representam o comportamento dinâmico dos vários componentes do sistema de transmissão através de uma simulação no programa comercial Matlab para obtenção dos resultados.
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Chuang, Jason C. "Variable Speed Flapping Wing Micro Air Vehicle using a Continuous Variable Transmission Design." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401813452.
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Grupenhof, Kyle D. "Continuously Variable Amplification Device for Semi-Active Vibration Control of Seismically Loaded Structures." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1337969875.
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Mower, D. Adam. "An Investigation of Wear-Resistant Coatings on an A390 Die-Cast Aluminum Substrate." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1765.pdf.
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Mullen, John A. "Analytical and Experimental Comparison of a Positive Displacement Water Pump Using an Infinitely Variable Transmission." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492125053378972.
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Ribeiro, Felipe. "Estudos de aplicações de transmissão continuamente variável (CVT) em geradores eólicos de médio porte." reponame:Repositório Institucional da UFABC, 2010.
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McCandless, John Gregory. "Design of a belt-driven continuously variable transmission." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12147.
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Wells, Dax B. "Investigation of Mechanical Differentials as Continuously Variable Transmissions." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2904.
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In recent years the increasing demand for fuel efficient and less pollutant vehicles has stimulated the development of hybrid and electric vehicles. These vehicle platforms often incorporate drivetrains which utilize multiple power sources for vehicle propulsion in an effort to increase fuel mileage and reduce emissions. Coupling multiple power sources, such as an internal combustion engine and electric motor(s), has new challenges in drivetrain design. Understanding the torque and rpm relationships within the power transmission device used to combine power sources is fundamental to overcoming the design challenges associated with hybrid and electric vehicle platforms. Results from this research include the fundamental torque and rpm relationships that exist in a multiple-input, single-output power transmission device. These results were deduced from a test that incorporated two separate power inputs into a differential which combined to produce a single output. Testing displayed that a differential has the ability to function as an infinitely variable transmission (IVT). Additionally, the challenges associated with using a differential as a multiple-input, single-output device were identified. Recommendations for overcoming these challenges are also presented herein. This work provides the basis for future work in powertrain optimization for multiple-input, single-output transmission devices.
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Lahr, Derek Frei. "Development of a Novel Cam-based Infinitely Variable Transmission." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35759.
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An infinitely variable transmission (IVT) is a transmission that can smoothly and continuously vary the speed ratio between an input and output from zero to some other positive or negative ratio; they are a subset of continuously variable transmissions (CVTs), which themselves do not have the ability to produce a zero gear ratio. In this thesis, the operation, analysis, and development of a novel, highly configurable, Cam-based Infinitely Variable Transmission of the ratcheting drive type is presented.
There are several categories of CVTs in existence today, including traction, belt, and ratcheting types. Drives of these types, their attributes, and associated design challenges are discussed to frame the development of the Cam-based IVT. The operation of this transmission is kinematically similar to a planetary gearset, and therefore, its operation is described with that in mind including a description of the six major components of the transmission, those being the cam, followers, carriers, planet gears, sun gears, and one way clutches. The kinematic equation describing its motion is derived based on the similarities it shares with a planetary gearset. Additionally, the equations for the cam design are developed here as the operation of the CVT is highly dependent on the shape of the cam. There are six simple inversions of this device and each inversion has special characteristics and limitations, for example, the available gear range. A method was developed to select the most suitable inversion, gearing, and follower velocity for a given application.
The contact stress between the rollers and cam is the limiting stress within the transmission. A parametric study is used to quantify the relationship between this stress and the transmission parameters. Based off those results, two optimization strategies and their results are discussed. The first is an iterative brute force type numerical search and the second is a genetic algorithm. The optimization results are shown to be similar and successfully reduced the contact stress by 40%. To further improve the transmission performance, several mechanisms were developed for this unique transmission. These include a compact and lightweight differential mechanism based on a cord and pulley system to reduce the contact force on the rollers. In addition, a unique external/inverted cam topology was developed to improve the contact geometry between the rollers and said cam. A prototype was built based on both the optimization strategies and these mechanisms and is described within. Finally, a Prony brake dynamometer with cradled motor was constructed to test the transmission; the results of those tests show the Cam-based IVT to be 93% efficient at low input torque levels.Master of Science
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Haupt, Brandon Levi. "Design and Analysis of a Positively Engaged Continuously Variable Transmission." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2635.pdf.
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Smith, Michael Henry. "Vehicle powertrain modeling and ratio optimization for a continuously variable transmission." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17801.
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Dalling, Ryan R. "An Investigation of Positive Engagement, Continuously Variable Transmissions." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2391.pdf.
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Tawi, K. B. "Investigation of belt misalignment effects on metal pushing v-belt continuously variable transmission." Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387629.
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Deacon, Michael. "Optimising the control of a passenger car diesel engine and continuously variable transmission." Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362258.
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Rose, Adam. "Application of a continuously variable transmission to engine boosting and exhaust energy recovery systems." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636513.
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Governments across the world are implementing legislation for ever more strict limits for vehicle emissions; combined with customer expectations for growing levels of performance and equipment, automotive manufacturers face a significant challenge. With the aim of meeting this challenge, downsizing is an established trend in passenger car engine development. However, since downsizing is commonly achieved through pressure charging (turbocharging, for example), the associated benefits in improved fuel economy and emissions are often obtained at the expense of engine dynamic response, and, consequently, vehicle driveability. This thesis presents predominantly simulation-based research into a novel combined charging system comprising a conventional turbocharger used in conjunction with a declutchable supercharger driven through a CVT. An initial investigation using this system in place of a variable geometry turbocharger on an already downsized passenger car diesel engine demonstrated greatly increased low speed torque as well as improved dynamic response. A downsizing project that involved replacing a naturally aspirated gasoline engine with a highly boosted engine with 40% of the original displacement formed the basis for more extensive investigations. Although it was unable to produce the low speed transient response of the naturally aspirated engine, in tip-in tests the CVT-supercharger system was shown to achieve the target torque much quicker than an equivalent system with a fixed supercharger drive ratio. However, balancing this with good fuel efficiency for the initial part load period was a complex trade-off. In vehicle acceleration simulations the CVT-supercharger system did not outperform the fixed drive ratio configuration, but on the CVT system the boost limit was reached at an early stage during the transients. Thus there may be potential to include an ‘over-boost’ facility, allowing boost pressure to temporarily exceed normal steady state limits in order to improve transient performance and bring it closer to that of the baseline vehicle. It is suggested that the CVT-supercharger provides the best flexibility for calibration and compromise between performance and fuel efficiency, perhaps incorporating different user-selectable modes (such as ‘economy’ and ‘sport’ modes).
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Messick, Matthew James. "An Experimentally-Validated V-Belt Model for Axial Force and Efficiency in a Continuously Variable Transmission." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85055.
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Rubber V-belt Continuously Variable Transmissions (CVT's) are commonplace in the Baja SAE collegiate design competition, and are also used widely in the power sports industry. These transmissions offer benefits of simplicity in mechanical design, consisting of only two pulleys, and are easy to use. While most teams in the competition use commercially available designs, custom designs are becoming more common, and the Baja team at Virginia Tech has used custom CVT's since the 2014 season. The design of these CVT's has relied heavily on trial and error, requiring significant adjustments to be made during the testing phase. In addition, only qualitative information is known for the relationship between efficiency and design parameters, such as sheave angle. The goal of this thesis is to create an improved V-belt model that may be used as a design tool. This model provides quantitative information about efficiency that can be used to make more informed design decisions. The belt model also provides insight into the magnitude and relationship between the axial forces in the pulleys. This can be used to create an initial design that is more accurate, and possibly reduce the time required for tuning. A CVT dynamometer was constructed to validate the analytical results for efficiency, and this will also serve as a tuning tool for future Baja teams at Virginia Tech. This thesis will advance the state of the custom CVT design and testing process at Virginia Tech, and hopefully lead to improved results at competition in the future.Master of Science
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Akehurst, Sam. "An investigation into the loss mechanisms associated with a pushing metal V-belt continuously variable transmission." Thesis, University of Bath, 2001. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341585.
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Hameer, Sameer Hameer Jaffer. "A comparative study and application of continuously variable transmission to a single main rotor heavy lift helicopter." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33969.
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Rotorcraft transmission design is limited by empirical weight trends that are proportional to the
power/torque raised to the two-thirds coupled with the relative inexperience industry has with the
employment of variable speed transmission to heavy lift helicopters of the order of 100,000 lbs
gross weight and 30,000 installed horsepower. The advanced rotorcraft transmission program
objectives are to reduce transmission weight by at least 25%, reduce sound pressure levels by at
least 10 dB, have a 5000 hr mean time between removal, and also incorporate the use of split
torque technology in rotorcraft drivetrains of the future. The major obstacle that challenges
rotorcraft drivetrain design is the selection, design, and optimization of a variable speed
transmission in the goal of achieving a 50% reduction in rotor speed and its ability to handle high
torque with light weight gears, as opposed to using a two-speed transmission which has inherent
structural problems and is highly unreliable due to the embodiment of the traction type
transmission, complex clutch and brake system. This thesis selects a nontraction pericyclic continuously variable transmission (P-CVT) as the best approach for a single main rotor heavy
lift helicopter to target the above mentioned obstacle for drivetrain design and provides
advancement in the state of the art of drivetrain design over existing planetary and split torque
transmissions currently used in helicopters. The goal of the optimization process was to decrease
weight, decrease noise, increase efficiency, and increase safety and reliability. The objective
function utilized the minimization of the weight and the constraint is the tooth bending stress of
the facegears. The most important parameters of the optimization process are weight,
maintainability, and reliability which are cross-functionally related to each other, and these
parameters are related to the torques and operating speeds. The analysis of the split torque type
P-CVT achieved a weight reduction of 42.5% and 40.7% over planetary and split torque
transmissions respectively. In addition, a 19.5 dB sound pressure level reduction was achieved
using active gear struts, and also the use of fabricated steel truss like housing provided a higher
maintainability and reliability, low cost, and low weight over cast magnesium housing currently
employed in helicopters. The static finite element analysis of the split torque type P-CVT, both
2-D and 3-D, yielded stresses below the allowable bending stress of the material. The goal of the
finite element analysis is to see if the designed product has met its functional requirements. The
safety assessment of the split torque type P-CVT yielded a 99% probability of mission success
based on a Monte Carlo simulation using stochastic- petri net analysis and a failure hazard
analysis. This was followed by an FTA/RBD analysis which yielded an overall system failure
rate of 140.35 failures per million hours, and a preliminary certification and time line of
certification was performed. The use of spherical facegears and pericyclic kinematics has advanced the state of the art in
drivetrain design primarily in the reduction of weight and noise coupled with high safety,
reliability, and efficiency.
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Narita, Keiichi. "Influences of metal-metal friction characteristics on the performance of metal V-belt type continuously variable transmission." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445840.
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Moyers, Joseph. "An investigation into novel hybrid vehicle powertrain configurations with the application of the Milner continuously variable transmission." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558891.
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Over the last few years there has been increasing level of environmental awareness both publicly and commercially. Depleting oil reserves, high fuel prices, environmental taxes, and challenging emissions targets have resulted in increasing pressure on the automotive industry to produce powertrain solutions which reduce fuel consumption and emissions. As a result of these increasing demands, the automotive industry has been investing and developing new technologies in order to reduce fuel consumption. One of the most notable of these new technologies has been the hybrid powertrain; the first production hybrid vehicle being introduced by Toyota, implementing a powersplitting hybrid system which can make use of series and parallel hybrid power paths. Since the introduction of this vehicle, many more hybrid vehicles have come to the market, where constant development is providing improvements in fuel consumption. This thesis details the work that has been carried out to investigate the performance potential of a series of novel hybrid vehicle powertrains which use of the Milner continuously variable transmission (MCVT). Each hybrid powertrain was selected as a system which has the potential to provide all of the functionality of the current Toyota power-splitting powertrain without suffering from its limitations, and providing additional system flexibility. The aim of the project was to assess the fuel economy and emissions characteristics of each of the proposed hybrid powertrains. The work undertaken throughout this study includes the development of full system models for each of the proposed hybrid vehicle configurations, alongside a full system model of an equivalent conventional manual vehicle powertrain. Experimental testing was also carried out on the internal combustion engine from which the simulation work was based, where exhaust emissions data were obtained. This thesis investigates the capability of each hybrid system to provide the required functionality, and the fuel economy performance of each of the powertrain configurations. A sensitivity analysis is made into the impact of each of the vehicle components on the overall vehicle fuel economy. An emissions analysis is made, comparing the total exhaust emissions from that of the hybrid vehicle powertrains with that of the conventional manual system. Recommendations are made for the selection and development of the hybrid vehicle system and components in order to maximise fuel economy and minimise total exhaust emissions.
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Ingvast, Johan. "Quadruped robot control and variable leg transmissions." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-600.
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Jones, Isaac R. "An Analysis of Analytical Methods to Produce a Varying Angular Output from a Constant Angular Input Using Gearsets." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2621.
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Research in developing a Positively Engaged Continuously Variable Transmission (PECVT) has been underway at Brigham Young University for some time. The inherent problems associated with embodiments of this type of transmission, namely the Non-Integer Tooth Problem (NITP), have been identified. This research is focused on the development of a Positively Engaged Piecewise Continuous Transmission (PEPCT), which is a subset of the PECVT. This document describes the hypothesis and analysis of using non-circular gearsets to overcome the NITP. This proposed solution enables a varying angular output from a constant angular input. In this research two analytical methods were evaluated based on their theory, mathematics and simulated results. Haupt's concept is shown to have discrepancies between the theorized and mathematical results which produce a gearset that has velocity spikes in its output. The second method, proposed by Danieli, describes the behavior on an infinitesimal level and the theorized results match up with the mathematical result. As a result of the analysis, Danieli's method is declared to produce a varying output from a constant input. The method requires only the definition of an input function that defines the shape of the pitch line similar to the pitch circle for circular gears. Using this function an infinitesimal approach is used to describe the interaction of consecutive contact points on the tooth profiles. This interaction takes into consideration adapted principles that are derived from the Fundamental Law of Gearing and the Law of Conjugate Action. With these principles defined it is possible to design gearsets that are capable of producing a varying angular output from a constant angular input. With the validation of the second method, and the principles defined by which it is governed, the proposed gearset is achievable allowing a PEPCT to be conceived. The proposed transmission utilizes the non-circular gearset to accelerate a secondary shaft to the next desired ratio while maintaining constant engagement. This concept is then analyzed and recommendations are made for the development of a Positively Engaged Continuously Variable Transmission.
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Groen, Benjamin Carson. "Investigation of DC Motors for Electric and Hybrid Electric Motor Vehicle Applications Using an Infinitely Variable Transmission." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2696.
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Since the early 1900's demand for fuel efficient vehicles has motivated the development of electric and hybrid electric vehicles. Unfortunately, some components used in these vehicles are expensive and complex. AC motors, complex electronic controllers and complex battery management systems are currently used in electric (EV) and hybrid vehicles. This research examines various motors and speed control methods in an attempt to help designers identify which motors would be best suited for an EV powertrain application. The feasibility of using DC motors coupled with an Infinitely Variable Transmission (IVT), to obtain an innovative new electric or hybrid electric powertrain is also presented. The results of this research include an extensive review of the many motor types including a comparison chart and motor hierarchy. An experiment was designed and built to test motorspeed control methods. Testing with two DC separately-excited motors and a differential as an IVT was also conducted. These tests revealed that field weakening appears to be a viable low-costspeed-control method. Testing of these motors, coupled with an IVT revealed that the output of a differential or planetary gear set can be controlled by varying the speed of the inputs. Combining this information in a product development mentality led to the concept of using one DC motor as a power or traction motor while another motor acts as a speed controller, with the method of speedcontrol on the speed control motor being field weakening. This concept allows most of the power to be delivered at an efficient rate with a simple form of speed control. This concept may also eliminate the need for expensive, complex electronic motor controllers. This approach could be used to improve the safety and reduce battery management requirements by lowering the operating voltage of the entire system.
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Lukas, Martynas. "Elektrinio variatoriaus panaudojimas dyzelinio variklio darbo optimizavimui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130611_134356-26786.
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Darbe nagrinėjami elektros varikliais valdomi planetiniai reduktoriai - variatoriai. Atliktos mokslinių straipsnių analizės metu susipažinta su įvairių rūšių automobiliuose naudojamomis transmisijomis: pateikta jų klasifikacija, apžvelgtos dažniausiai naudojamos transporte pavarų dėžės. Pateikta tyrimo metodika, apžvelgti eksperimentinių tyrimų įrenginiai ir priemonės. Atlikti elektros varikliu valdomo planetinio reduktoriaus eksperimentai su suprojektuotu tyrimo stendu. Palygintos belaipsnės pavarų dėžės su parinktu dyzeliniu varikliu, bei pateiktos išvados ir rekomendacijos.This thesis analyzes the electric motor which controlled by planetary gearboxes - variator. Accomplished scientific articles during the analysis been familiarized with different kinds of transmissions which used in vehicles: submitted their classification, reviewed most commonly gearbox which used in transport. Submitted research methods, an overview of experimental research equipment and facilities. Performed experiments of electric motor controlled by planetary gear with designed study stand. Were was compared continuous variable transmission with a selected on diesel engine, submitted conclusions and recommendations.
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Schneider, Christopher William. "Derivation of solution for elliptical elastohydrodynamic contact patches with side-slip and its application to a continuously variable transmission." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4715.
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Elastohydrodynamic lubrication (EHL) allows transfer of power and forces in gears and rolling bearings without surface-to-surface contact and is the basis for a continuously variable transmission studied in this report. Previous research constructed models and derived solution methods, but often lacked full explanations of the approach and was usually applied to limited and specific cases. This report precisely develops the numerical solution of EHL contact and includes the more general cases of elliptical contacts and side-slip. The model and numerical method are validated on known benchmark cases and test results. Side-slip is investigated and the results shown in this report. Finally, the model is used to determine the film thickness and pressure of a contact patch under identical conditions to that in a physical drive developed by Fallbrook Technologies in Austin, TX. A minimum film thickness of 0.8978 [mu]m is found, setting a benchmark for the maximum allowable surface roughness values to prevent surface-to-surface contact. Additionally, under normal drive conditions the film thickness to surface roughness ratio is in the range of ideal values for maximum life.text
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D'ANDREA, Danilo. "Design and Development of a Continuously Variable Transmission (CVT) for High Efficiency and Low Weight Heavy Duty Applications." Doctoral thesis, 2020. http://hdl.handle.net/11570/3179841.
Full textAbstract:
The PhD project aims to develop a new type of CVT for application on a street sweeper, using the Jarchow model which involves the use of a multi-range transmission with hydraulic first mode. The further innovative aspects of the transmission concern the simulation of an energy recovery system and the optimization of the hydraulic units efficiency through the study of innovative coatings applicable to rotating groups of pumps and hydraulic motors. As regards the development of the transmission, Simcenter Amesim simulation software was used. The results showed that applying a CVT input coupled with HSM (hydraulic starting mode) allows the use of only 6-7 kW, and therefore decreases the power of the ICE which is initially equal to 25 kW.
As for the innovative coatings, both superhydrophobic coatings and textured coatings were tested in order to evaluate their applicability in the hydraulic field. For the superhydrophobic coatings the mechanical resistance was tested through scratch tests and tensile tests, while for the textured coatings tribological tests were performed to evaluate the CoF.
Very promising results have been obtained from tribological tests on textured coatings, while the poor resistance and durability, shown by the failure analysis, limits the application of CVT input coupled in the hydraulic field.
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Chanumolu, Raviteja. "A Novel Hybrid Vehicle Architecture : Modeling, Simulation and Experiments." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/3585.
Full textAbstract:
Electric and hybrid vehicles are particularly suited for use in urban areas since city transportation is mainly characterized by relatively short driving distances, low continuous power requirements, long idling times and high availability of regenerative braking energy. These characteristics, when carefully incorporated into the design process, create valuable opportunities for developing clean, efficient and cost effective urban vehicle propulsion systems.
In the first part of the thesis, we present data collected in the city of Bangalore, India from a very commonly seen mode of transportation for hire in India and other emerging economies, namely a three-wheeled vehicle known as the “auto-rickshaw”. From a statistical analysis, it is shown that the typical range is 72.5 km with a mean speed of 12.5 km/h. More than 60% of the time the auto-rickshaw is stationary or has a speed of less than 5 km/h. From a model of the auto-rickshaw, it is shown from simulations that 4 kW DC motor and about 10 kWh of electrical energy is enough to meet 80% of typical requirement. Based on this finding, in this thesis, a novel parallel hybrid architecture is proposed where two 2 kW DC hub motors are directly mounted on the wheels and an internal combustion (IC) engine output is connected to the stator of the DC hub motors to provide additional power when required. To match load and speed, a continuously variable transmission (CVT) is placed in-between the IC engine and the DC hub motor. The proposed hybrid configuration adds speed to the wheel output unlike the normal power split configuration which adds torque.
One of the main objective of this work is to study and compare the performance of the above novel speed-addition and compare with the typical torque-addition configuration. A MATLAB/Simulink model for both the configurations, with DC hub motor and a small IC engine, has been created and the fuel consumption has been calculated. It is shown that the proposed speed-addition concept gives better fuel efficiency for the standard modified Indian Driving Cycle. The models have also been compared for actual driving data and an optimal control strategy has been developed using dynamic programming. It is again shown that the proposed speed-addition concept results in better fuel economy.
In the last part of the thesis, a low cost experimental test-bed consisting of an auto-rickshaw
IC engine, a CVT and a 2 kW DC hub motor has been developed to validate the speed-addition concept and compare with the torque-addition configuration. The torque-speed curves of the IC engine, the DC motor and both of them together, in the speed and torque-addition configuration, have been obtained. It is shown that the speed-addition concept does indeed work and the obtained results are significantly different from the torque-addition configuration.
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Chanumolu, Raviteja. "A Novel Hybrid Vehicle Architecture : Modeling, Simulation and Experiments." Thesis, 2017. http://etd.iisc.ernet.in/2005/3585.
Full textAbstract:
Electric and hybrid vehicles are particularly suited for use in urban areas since city transportation is mainly characterized by relatively short driving distances, low continuous power requirements, long idling times and high availability of regenerative braking energy. These characteristics, when carefully incorporated into the design process, create valuable opportunities for developing clean, efficient and cost effective urban vehicle propulsion systems.
In the first part of the thesis, we present data collected in the city of Bangalore, India from a very commonly seen mode of transportation for hire in India and other emerging economies, namely a three-wheeled vehicle known as the “auto-rickshaw”. From a statistical analysis, it is shown that the typical range is 72.5 km with a mean speed of 12.5 km/h. More than 60% of the time the auto-rickshaw is stationary or has a speed of less than 5 km/h. From a model of the auto-rickshaw, it is shown from simulations that 4 kW DC motor and about 10 kWh of electrical energy is enough to meet 80% of typical requirement. Based on this finding, in this thesis, a novel parallel hybrid architecture is proposed where two 2 kW DC hub motors are directly mounted on the wheels and an internal combustion (IC) engine output is connected to the stator of the DC hub motors to provide additional power when required. To match load and speed, a continuously variable transmission (CVT) is placed in-between the IC engine and the DC hub motor. The proposed hybrid configuration adds speed to the wheel output unlike the normal power split configuration which adds torque.
One of the main objective of this work is to study and compare the performance of the above novel speed-addition and compare with the typical torque-addition configuration. A MATLAB/Simulink model for both the configurations, with DC hub motor and a small IC engine, has been created and the fuel consumption has been calculated. It is shown that the proposed speed-addition concept gives better fuel efficiency for the standard modified Indian Driving Cycle. The models have also been compared for actual driving data and an optimal control strategy has been developed using dynamic programming. It is again shown that the proposed speed-addition concept results in better fuel economy.
In the last part of the thesis, a low cost experimental test-bed consisting of an auto-rickshaw
IC engine, a CVT and a 2 kW DC hub motor has been developed to validate the speed-addition concept and compare with the torque-addition configuration. The torque-speed curves of the IC engine, the DC motor and both of them together, in the speed and torque-addition configuration, have been obtained. It is shown that the speed-addition concept does indeed work and the obtained results are significantly different from the torque-addition configuration.
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Cho, Chang-Yeh, and 卓昌衍. "Vibrations of Flat Belt Continuously Variable Transmission." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/41258074367675159689.
Full text
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Tu, Yu-Jui, and 杜育瑞. "Electronically-Controlled Continuously Variable Transmission Systems for Motorcycles." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/x9htrv.
Full textAbstract:
碩士崑山科技大學
機械工程研究所
91
The V-belt Continuously Variable Transmission (CVT) systems are widely used in almost all kinds of scooters. The major mechanism of the traditional CVT is composed of centrifugal rollers, the compression spring and the torque cam. They are used to adjust the speed ratios for complying with the engine speed and the rear wheel load. In addition to the low transmission efficiency at the lower speed, the centrifugal rollers and movable flange have the worn-up problems which may reduce the materials life-cycle. In order to improve these problems, the aim of our study is to design a brand new Electronically-Controlled Continuously Variable Transmission (ECCVT) system to overcome the limitation of the traditional CVT mechanism. In stead of the centrifugal rollers and movable flange, the new ECCVT use the electronic control equipment to change the speed ratios. Therefore, it gets rid of the material worn-up problems. The ECCVT system can also provide the overall system with higher durability and reliability, and the accurate movement. Combined with the sensor signals of the engine speed, the vehicle speed and the TPS (Throttle Position Sensor), the suitable speed ratio can be calculated. One ECCVT system can be used for different types of engines and in different kinds of driving conditions. By controlling the shift timing and the changing speed of speed ratios, the ECCVT can fulfill the various engine configurations and loading. Therefore, the ECCVT system can be expected to have better power transmission and higher energy transferred efficiencies. At the present stage, the design and experiment test of the new ECCVT system have been accomplished, the experiment results show that the ECCVT system can provide a better transmission efficiency at the lower speeds and the worn-up problems can be avoided. When the external load is changed from 1.16 N-m to 5.8 N-m, the transmission efficiency increases from 45% to 80% obviously. But the increasing tendency is becoming smoothly when the load is above 3.48 N-m. Based on the dynamic test data, the average transmission efficiency of the ECCVT system is 5% higher than that of the traditional CVT system. But, if the speed changed of speed ratio is too fast, the transmission efficiency will drop obviously while the speed ratio starts to change and latter-on the transmission efficiency will increase with the increasing speed ratios.
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WANG, YOU-HAN, and 王郁涵. "Stationary Bike with Continuously Variable Transmission of Resistance." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/c76g5x.
Full textAbstract:
碩士南臺科技大學
機械工程系
104
This research aimed to design a set of outdoor use conform resistance-type stepless load foot-fitness, which target groups for the elderly or outdoor public sports equipment users, take advantage of our home fitness equipment nearby, we will be able to effectively carry muscle power intensive training. This research purpose is a congenital conditions for the Continuously Variable Transmission system, by modifying the original system parts. In the part of the drive mechanism, using compound gear train to increase speeds and employing conventional friction clutch jig, the rider can follow the speed to the level depends on the size of the resistance. And the use of 50CC, 125CC, 125CC (modified) to compare its transmission speed difference. Then set design requirements and design constraints, the use of variable speed spring constant in 0.09 kg / mm and centrifugal roller 132g internal system variable speed of synthesis, it can be found in the original speed 8500rpm down to 1000rpm, after the number of teeth were smaller portion of design, down to the speed of this speed is more suitable for human pedaling. Discussion to the equipment moving, continuously variable transmission system, clutch throwing, and the relationship between the resistance of the friction generated by the jig, that it will be fixed at 25rpm speed, the No friction power is 107W, has been friction power is 139W; and when the No friction at 100rpm rotational speed rise when power is 171W, has been friction power is 293W, there is significant resistance values of the output power from the point of view changes, and as much as possible to speed up operations to achieves better training effect. Part of the strength of the equipment, by using ANSYS simulation software, model analysis results obtained which in different load conditions found by joints in the foot pedal to achieve the degree of damage when the force is applied to the 1470N,and this reinforcement can be a safety factor upgrade from 0.7 to 0.9, while the rest of the results of the simulation of lower extremity sports equipment, all within a safe range, the display of safety equipment are met expectations.
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Kumar, K. Vinod. "Study and Design of Automobile Continuously Variable Transmission." Thesis, 2015. http://ethesis.nitrkl.ac.in/7137/1/Study_Kumar_k_2015.pdf.
Full textAbstract:
An individual need not be an automobile designer to comprehend that the lesser fuel a motor devours the better it is, and the less poisons delivered, and the cleaner the air we inhale. Lamentably, enhancing the variables in that mathematical statement is getting to be progressively troublesome. To accomplish extra mileage changes, we have started to concentrate on expanding productivity in ranges where enhancements are significantly more troublesome and expensive to attain to - to a great extent on powertrain segments, for example, the transmission This stems from the way that transmissions work over a scope of force conditions, for example, low speed-high torque to fast low torque, and in addition through an assortment of apparatus proportions. To accomplish picks up here, we have tested the traditional speculation connected with powertrain capacities and plans. Ordinary powertrain arrangements comprise of an inner burning motor working over an extensive variety of torque and pace conditions and a transmission that has, by examination, just a couple of discrete apparatus proportions. The operational rationality of customary powertrains makes it hard to achieve most extreme motor fuel proficiency on the grounds that the open doors for working at the least fuel utilization or best "brake particular fuel utilization" are confined and by and large don't concur with the torque and rate conditions forced on the motor by the vehicle. Utilizing a CVT-arranged powertrain, the motor works at greatest burden conditions. This permits the motor to work at or close to its best brake particular fuel utilization rate, which implies that the motor is working at its most elevated normal adiabatic efficiencies. For inner ignition motors this would be 36 %, while for diesel motors it is 45 %. This task report assesses the flow condition of CVTs and upcoming innovative work, set in the connection of past improvement and issues customarily connected with it. The basic speculations and components are likewise talked about.
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HuangDeng-Jin and 黃登進. "Creative Design on an Electronically-Controlled Continuously Variable Transmission." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/91775318769561790063.
Full textAbstract:
碩士崑山科技大學
機械工程研究所
95
This research is mainly on the creative designing of electronically- controlled continuously variable transmission (ECVT) for motorcycles, and aim to get rid of the constant speed ratio curve restriction of the traditional CVT. Part of the engine power is transmitted to the transmission system for speed ratio change. A synchronous mechanism is use to reach the function of engage and disengage which is accomplished via a step motor. A power screw is used to actuate the movable sheave of the driving pulley to change the speed ratio. The computer software MATLAB/Simulink is used in this research for analyzing the performance of the electronically controlled continuously variable transmission system. Speed ratio change curve of the original CVT system is simulated by using the ECVT system. Simulation for Time Constant and Time Delay of the ECVT system is also made for better understand the ability of the ECVT system. Power consumption of the ECVT system is evaluated prior to calculate the vehicle acceleration in order to analyze the performance of the transmission system. Experiments using motor as power source which is split into power screw and transmission system are used to verify accuracy of the simulation.
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Vallabhaneni, Naveen Kumar. "Continuously Variable Rotorcraft Propulsion System: Modelling and Simulation." 2011. http://trace.tennessee.edu/utk_gradthes/1033.
Full textAbstract:
This study explores the variable speed operation and shift response of a prototype of a two speed single path CVT rotorcraft driveline system. Here a Comprehensive Variable Speed Rotorcraft Propulsion system Modeling (CVSRPM) tool is developed and utilized to simulate the drive system dynamics in steady forward speed condition. This investigation attempts to build upon previous variable speed rotorcraft propulsion studies by:
1) Including fully nonlinear first principles based transient gas-turbine engine model
2) Including shaft flexibility
3) Incorporating a basic flight dynamics model to account for interactions with the flight control system.
Through exploring the interactions between the various subsystems, this analysis provides important insight into the continuing development of variable speed rotorcraft propulsion systems.
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Hu, Bi Shyang, and 胡筆祥. "OPTIMAL DESIGN FOR CONTINUOUSLY VARIABLE TRANSMISSION OF RUBBER V-BELT." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/97877802771202129905.
Full textAbstract:
碩士國立臺灣大學
機械工程學系研究所
86
The design for V-belt CVT is a process of trial and error for multivariable. The objective function and constraint conditions are affected by multivariable. It is a difficult problem for designers that how to decide the variable value. Here use the simulated annealing algorithm, one of the numerical method of the optimization, to transfer the process into the computer search such that can save the time of finding the optimal solution. The simulated annealing algorithm is an optimization algorithm developed by simulating the annealing phenomenon of a solid in the process of finding solution, which provides an effective and general technique to find the global optimum solution or the near-global optimum solution, no matter what the objective function or the constraint conditions can be differentiated or cannot be differentiated. Furthermore, the design of CVT is necessary to match the various performances of engine, such as the maximum torque output, the quantity of consuming oil, the quantity of CO emission and the quantity of HC emission. Those quantities of performance of engine only can be obtained by experiment and are always discrete due to the limitation of time and expenditure. It is a challenge for designer to take advantage of the discrete experimental quantities of engine in the process of the optimization, so in this paper Bessel Method of curve fitting and Tensor Product Method of surface fitting were used to transform the originally discrete experimental quantities of engine into the data to be searched automatically in the process of optimization so as to design the fundamental construction for CVT. An engine was taken as example in this paper. According to the outcome of optimization of each subobject, some conflicts existed among subobjects such that subobjects couldn''t be satisfied simultaneously by the values of one set of variable, after optimal match design between CVT and engine was performed. The Compromise Programming Method was used to analyze the multiobjective function, and the effects of different value of exponent and weight were compared.
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Yoon, Hee-Duk. "Evaluation of a continuously variable transmission utilizing non-circular gears." 1995. http://catalog.hathitrust.org/api/volumes/oclc/33141582.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1995.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 75-77).
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Chung, Yuan-Yung, and 鍾源勇. "Dynamic analysis of a rubber-v-belt continuously variable transmission." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/67274736965893643265.
Full textAbstract:
碩士國立清華大學
動力機械工程學系
85
Smoother speed change, high speed-ratio range at the rated speed and load,a simpler mechanism with low cost and less maintenance, etc., have been theultimate goals for transmission design engineers. The belt-driven CVT can nearlyfulfill these requirements. However, the characteristics of less efficiency andlower load-carrying capacity have hampered the applications. This research presents an analytical and experimental investigation on the dynamic behaviors of the CVT under steady-state conditions. It includes the analyses of the speed-ratio-changing mechanisms, the force and stress distributions over the contact region, the vibration of the free span, the power-loss mechanisms and efficiency ofthe entire system, etc. The low efficiency of the V-belt CVT may attribute to the following reasons:slip, radial sliding, vibration, and hysteresis due to bending, shear, andcompression of the V-belt. These may result from the characteristics of the V-belt itself and the interaction between the belt and sheaves. By introducing thebending rigidity of the belt into equilibrium equations, a contact analysis isperformed to determine the force and stress distributions, and the radius of curvature of the belt. This formulation provides a basis for the estimation of power loss by computing the hysteresis and friction losses between the belt andsheaves. The free span of the belt is considered as an axially moving elastic material.The equation of motion, governing the dynamic behaviors of the free span of thebelt in the transverse direction, is derived by employing a mixed variationprinciple. The geometrical boundary and initial conditions are determined from the aforementioned contact analysis of a practical CVT system. A parametricstudy, such as the variation of the belt tension, transporting velocity, on natural frequencies of the belt is then performed by using assumed-modes method. An analysis of parametric instability is performed by the periodic variations of the belt shape and tension. These results may be further utilized in the design of belt-driven CVT systems. A quantitative analysis of the power-loss mechanisms, on the basis of the contact behaviors between the belt and sheaves, is accomplished. The efficiency of a motorcycle CVT under various operating conditions is evaluated by considering the bending hysteresis loss, shear hysteresis loss, shear deflection andfriction loss of radial displacement. These results are further verified by experiments. A methodology for the design of the entire rubber V-belt CVT system can be constructed on the basis of this research, that is applicable for the CVT under various operating conditions.
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He, Wei-Ta, and 何威達. "Numerical Modeling of Heat Dissipation in the Continuously Variable Transmission." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9h5k86.
Full textAbstract:
碩士國立屏東科技大學
車輛工程系所
105
In this study, the temperature of solid/fluid inside a continuously variable transmission (CVT) of a 400 cc scooter is investigated numerically utilizing ANSYS FLUENT. The moving reference frame(MRF)techniquewith conjugate heat transfer between gases and solid rotation/translationare implemented to carry out the simulation.The emphasis of the present study is put on the effects of CVT housing configuration, belt’s thermal conductivity,belt’s speed ratio and the heat dissipated from the crankcase on the thermal-flow-field of CVT. The numericalresults show that it is foundthat the proposed design of partition plate inside the CVT housing can direct the flow to belt and prevent the heat fluidremainin the CVT, and can further decrease the temperatures of the belt and pulley.The increase of thermal conductivity of belt will increase the average temperature of belt but minimizethe temperature difference on it. In addition, the temperature of driven pulley will decrease when belt transition from high ratio to low ratio due to the increase of itsrotational speed. The heat dissipation from the crankcase to CVT housing is also exploredthat the ribs in the housing adjacent to the crankcase served as the fin to enhance the heat transfer from engine to CVT housing.In comparison with the methods proposed by other researchers, thismethodis found to be the most detailed model. Keyword: CVT、CFD、Continuously Variable Transmission、Heat Dissipation
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Chen, Jun-Hong, and 陳俊宏. "Design and Fabrication of an Impulse Type Continuously Variable Transmission." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/9hbr43.
Full textAbstract:
碩士國立虎尾科技大學
機械與機電工程研究所
100
The purpose of this study proposed a new type of continuously variable transmission mechanism including kinematic analysis, kinetostatic analysis, and prototype fabrication. First, we collected the continuous variable transmission mechanisms literature and patents to analyses the basic operation principle and generalized a conclusion to create a new design of a coaxial impulse Type continuously variable transmission. This transmission is possessed a three-link and one degree of freedom. Then, according to the new concept, a 3D solid modeling was drawn by using Solid Works drawing software to illustrate the operation principle. In accordance with the vector loop method kinematic analysis and kinetostatic analysis was completed and using ADAMS simulation software to verify the correctness of these analyses. Finally, base on the results of this research a prototype was fabricated. The results in this study showed that the new design presented in this research is a feasible design and be able to provide the design reference direction for continuously variable transmission mechanisms.
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"Effect of Continuously Variable Unit on Powertrain Dynamics." University of Technology, Sydney. Faculty of Engineering, 2004. http://hdl.handle.net/2100/340.
Full textAbstract:
This thesis studies the dynamic model and simulation of a Half-Toroidal (HT) type Continuously Variable Unit (CVU) integrated into a conventional powertrain. A simplified parametric model of a HT-CVU is constructed using Finite Element Method (FEM) in which the continuous variable speed unit is discretized into lumped masses, spring and damper elements. Linearized Finite Elements (FE) have been used to model the contacts between the toroids and rollers. The phenomenon of slip and spin associated with the rolling-slipping contacts of the traction drives are modelled kinematically. All Finite Elements including the CVU model are integrated into the complete powertrain system. Free Vibration Analysis (FVA) of the multi degree of freedom system is carried out for torsional vibration for High Gear (HGR) and Low Gear Ratio (LGR) conditions. Further, FVA is carried out with a lock-up clutch engaged at high speed range. The results of the FVA indicates significant changes in natural frequencies and corresponding mode shapes for both HGR and LGR condition with a change in HT-CVU gear ratios. Change in natural frequencies and mode shapes for both HGR and LGR conditions are also observed for varying contact torsional stiffness. The change is significant till a certain value of contact torsional stiffness. Further increase in contact torsional stiffness within the HT-CVU does not affect the natural frequencies and corresponding mode shapes significantly. The results of the modal analysis carried out for a HT-CVU integrated powertrain with a lock-up clutch engaged at high speed range illustrates the ability of the lock-up clutch to simultaneously suspend engine and roller element excitation. However, for certain natural frequencies the modal analysis of the integrated powertrain system indicates suspension of engine and input toroid but increased excitation for the roller element of the HT-CVU. The transient dynamic analysis is carried out to understand the behaviour of the CVU integrated into the complete powertrain and to identify and possibly correct potential problems associated with the system. The simulation is carried out for constant and variable throttle conditions for the powertrain with and without a lock up clutch engaged at high speed ranges. A piecewise curved gear ratio map is assumed for all conditions. All analyses are carried out for throttle 'tip-in' condition. The results of the transient dynamic analysis indicate that the transient responses of input and output rollers of the HT-CVU exist when clutch change occurs during vehicle acceleration period from stand still condition. The clutch change also leads to disturbances in the HT-CVU output torque to driveline and in vehicle speed. This leads to imperfect drive feel for the driver. The simulated vehicle velocity indicates powerful acceleration characteristics of the HT-CVU integrated powertrain. Engine harmonics is modelled as a rich collection of various forcing frequencies. These frequencies impress on the response of both the roller and output toroid and are observed in the simulation. Stability analysis is carried out on the powertrain to understand the effect of damping in the tyres and damping within the HT-CVU on the stability of the powertrain. Severe or even unstable response of the HT-CVU takes place if the damping in the HT-CVU and/or the tyres is insufficient during the initial acceleration period and later after the clutch change occurs and when the vehicle is at high speeds. The results of the stability analysis lead us to reason with confidence that the tyre and HT-CVU damping have an effect on the dynamic characteristics and the stability of the system. The response of the powertrain becomes stable when a lock-up clutch is applied over the high speed ranges even if the damping in the tyres remains insufficient. The modal damping ratios for stable and unstable conditions are also discussed. Future investigations need to be carried out in order to understand in depth the fluid-metal interaction in the HT-CVU. This can be achieved by modelling in non-linear drag torque which would act on the HT-CVU elements.
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Tsung, Chung-Hsien, and 鐘顯宗. "PID Controller Design for Continuously Variable Transmission Systems for Wind Turbine." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/60295159932838888793.
Full textAbstract:
碩士崑山科技大學
機械工程研究所
105
Climate change brought about the threat to humanity and the earth, due to which countries began to focus on environmental protection and energy conservation to reduce to dependency on fossil fuel. At present, focus has been centered on development of renewable energy, such as solar energy, the wind, tidal energy and geothermal energy. One of most used and researched field is wind energy and usage of wind turbines. At present, most of the transmission systems of wind turbines are based on Planetary Gear Box (PGBs). In this paper, we mainly study the use of Electronically-Controlled Continuously Variable Transmission (ECVT). Motor and gear rotation is used to change the linear position of screw of ECVT drive disk, thus controlling the ECVT pulley diameter for the front end of transmission train. Thus by controlling the axial displacement of the screw through control of rotational speed and rotational direction, the diameter and rate of change of diameter of the front end pulley of CVT powertrain can be controlled. This paper is based on designing of a PID controller logic to control the ECVT powertrain gear ratio to provide Steady-speed and Power-split function for output (rear-end) shaft of the ECVT powertrain. In this research, main focus is development of PID with manual fine-tuning, since the output torque changes according to the load of generator used for electricity generation. After experimentation and fine-tuning of PID controller, steady-speed output and power-split function was achieved. This concludes that PID controller with ECVT powertrain is an ideal solution for providing a stable and efficient output through a wind turbine.