Continuously Variable Transmission (CVT) offers a continuum of gear ratios between desired limits. This allows the engine to operate more time in the optimum range. In contrast, traditional automatic and manual transmissions have several fixed transmission ratios forcing the engine to operate outside the optimum range. The need for a transmission system and the working principle of CVT has been discussed in depth. An attempt has been made to understand the contribution of Hydraulic Actuators, which is an integral part of a CVT. Furthermore, the question of how and why a Torque Converter has effectively replaced a conventional clutch has been answered. The materials used, constructional aspects and stress analysis of the belt has been discussed in detail. A graphical comparison of fuel efficiency between a manual transmission and a CVT in different high end vehicles is included. Recent developments in clamping force control for the push belt Continuously Variable Transmission (CVT) have resulted in increased efficiency in combination with improved robustness. Current control strategies attempt to prevent macro slip between elements and pulleys at all times for maximum robustness.
This document presents information on continuously variable transmissions (CVTs). It discusses the three main types of CVTs: pulley-based, toroidal, and hydrostatic. Recent developments in CVTs from Subaru, Honda, and Nissan are outlined, focusing on improved fuel efficiency and driving experiences. Advantages include improved fuel efficiency and engine performance, while disadvantages include higher costs and limitations for high-torque applications. Future applications in hybrid vehicles are also discussed.
1) The document reports on a student project to study, analyze, and build a model of a continuously variable transmission (CVT).
2) It discusses various types of CVTs, including belt-driven, toroidal, magnetic, ratcheting, hydrostatic, and cone-based systems.
3) For their project, the students chose to model a cone-based CVT, building a wooden prototype and using a speedometer to demonstrate variable output speeds.
This document summarizes a seminar report on infinitely variable transmissions. It begins with an introduction to different types of transmissions, defining IVT as a type of continuously variable transmission. The key elements of IVT are described as the input gear set, variator, and planetary gear set. The variator is the heart of IVT and can be a toroidal CVT. A toroidal CVT works by varying the angle of roller discs between input and output discs to provide infinite gear ratios. IVT combines a toroidal CVT with a planetary gear set to provide continuous variation between zero output speed and the maximum while keeping the engine at optimal RPM. Advantages include improved fuel efficiency and acceleration, while drawbacks include
This document discusses continuous variable transmissions (CVTs). It begins by explaining the basic function of a transmission to change the speed ratio between an engine and wheels. It then discusses problems with manual and automatic transmissions. The benefits of a CVT are that it provides constant engine torque optimization and improved fuel efficiency through a continuously variable transmission ratio. The main types of CVTs are pulley-based, toroidal, and hydrostatic. Pulley-based CVTs vary the gear ratio by adjusting the distances between two pulley sheaves. Toroidal and hydrostatic CVTs use different mechanisms to provide a continuous range of transmission ratios. The document concludes by discussing CVT control systems and advantages/disadvantages of
A continuously variable transmission (CVT) can seamlessly change through an infinite number of gear ratios, allowing the engine to operate at optimal power and efficiency levels. CVTs are being applied in automobiles, heavy industry, oil production, and wind energy technology. They provide benefits like improved fuel economy and reduced emissions compared to traditional transmissions. While CVTs have fewer moving parts, their intricate designs require expensive materials and there is limited expertise with the new technology.
This document discusses continuously variable transmissions (CVTs). It describes the key parts of a CVT including a belt, fixed sheaves, adjustable sheaves, and centrifugal weights. It explains how a CVT works by varying the diameter of the input and output sheaves to provide an infinite range of gear ratios. CVTs allow the engine to run at optimal speeds for efficiency. Some advantages are smooth gear changes, compact design, and cost effectiveness. CVTs are used in many passenger vehicles and motorcycles.
This presentation discusses continuously variable transmissions (CVTs). It begins with an introduction to transmission systems and the three main types: manual, automatic, and CVT. It then defines a CVT as a transmission that can change seamlessly through an infinite number of gear ratios. The presentation outlines the history and development of CVTs, from da Vinci's sketches to their use in modern cars. It describes the two most common types of CVTs: pulley-based and toroidal. It concludes with examples of CVT applications in vehicles, machinery, and a simulation comparing the fuel efficiency of a manual vs. CVT in an Audi A6.
Group 3 presented on continuously variable transmissions (CVT). There are several types of CVTs but they all aim to provide infinite gear ratios between maximum and minimum values without discrete steps. CVTs use mechanisms like pulleys and belts or discs and rollers to vary the drive ratio continuously. They allow the engine to run at optimal RPMs for efficiency and provide smooth, stepless acceleration. CVTs are simpler than conventional automatic transmissions and more efficient, using 25% fewer parts. They are emerging as an important technology for enhanced driving performance and fuel efficiency.
This document presents information on continuously variable transmissions (CVTs). It discusses the three main types of CVTs: pulley-based, toroidal, and hydrostatic. Recent developments in CVTs from Subaru, Honda, and Nissan are outlined, focusing on improved fuel efficiency and driving experiences. Advantages include improved fuel efficiency and engine performance, while disadvantages include higher costs and limitations for high-torque applications. Future applications in hybrid vehicles are also discussed.
1) The document reports on a student project to study, analyze, and build a model of a continuously variable transmission (CVT).
2) It discusses various types of CVTs, including belt-driven, toroidal, magnetic, ratcheting, hydrostatic, and cone-based systems.
3) For their project, the students chose to model a cone-based CVT, building a wooden prototype and using a speedometer to demonstrate variable output speeds.
This document summarizes a seminar report on infinitely variable transmissions. It begins with an introduction to different types of transmissions, defining IVT as a type of continuously variable transmission. The key elements of IVT are described as the input gear set, variator, and planetary gear set. The variator is the heart of IVT and can be a toroidal CVT. A toroidal CVT works by varying the angle of roller discs between input and output discs to provide infinite gear ratios. IVT combines a toroidal CVT with a planetary gear set to provide continuous variation between zero output speed and the maximum while keeping the engine at optimal RPM. Advantages include improved fuel efficiency and acceleration, while drawbacks include
This document discusses continuous variable transmissions (CVTs). It begins by explaining the basic function of a transmission to change the speed ratio between an engine and wheels. It then discusses problems with manual and automatic transmissions. The benefits of a CVT are that it provides constant engine torque optimization and improved fuel efficiency through a continuously variable transmission ratio. The main types of CVTs are pulley-based, toroidal, and hydrostatic. Pulley-based CVTs vary the gear ratio by adjusting the distances between two pulley sheaves. Toroidal and hydrostatic CVTs use different mechanisms to provide a continuous range of transmission ratios. The document concludes by discussing CVT control systems and advantages/disadvantages of
A continuously variable transmission (CVT) can seamlessly change through an infinite number of gear ratios, allowing the engine to operate at optimal power and efficiency levels. CVTs are being applied in automobiles, heavy industry, oil production, and wind energy technology. They provide benefits like improved fuel economy and reduced emissions compared to traditional transmissions. While CVTs have fewer moving parts, their intricate designs require expensive materials and there is limited expertise with the new technology.
This document discusses continuously variable transmissions (CVTs). It describes the key parts of a CVT including a belt, fixed sheaves, adjustable sheaves, and centrifugal weights. It explains how a CVT works by varying the diameter of the input and output sheaves to provide an infinite range of gear ratios. CVTs allow the engine to run at optimal speeds for efficiency. Some advantages are smooth gear changes, compact design, and cost effectiveness. CVTs are used in many passenger vehicles and motorcycles.
This presentation discusses continuously variable transmissions (CVTs). It begins with an introduction to transmission systems and the three main types: manual, automatic, and CVT. It then defines a CVT as a transmission that can change seamlessly through an infinite number of gear ratios. The presentation outlines the history and development of CVTs, from da Vinci's sketches to their use in modern cars. It describes the two most common types of CVTs: pulley-based and toroidal. It concludes with examples of CVT applications in vehicles, machinery, and a simulation comparing the fuel efficiency of a manual vs. CVT in an Audi A6.
Group 3 presented on continuously variable transmissions (CVT). There are several types of CVTs but they all aim to provide infinite gear ratios between maximum and minimum values without discrete steps. CVTs use mechanisms like pulleys and belts or discs and rollers to vary the drive ratio continuously. They allow the engine to run at optimal RPMs for efficiency and provide smooth, stepless acceleration. CVTs are simpler than conventional automatic transmissions and more efficient, using 25% fewer parts. They are emerging as an important technology for enhanced driving performance and fuel efficiency.
This document provides an overview of continuously variable transmissions (CVTs) and hybrid electric vehicles (HEVs). It discusses the history and development of CVTs, including early inventions. The key components of CVTs are described, including the primary and secondary clutches and different types of belts. The document explains how CVTs work by varying the gear ratio through movement of the sheaves. Research and applications of CVTs are expanding, and they are beginning to be used more widely in vehicles. Hybrid vehicles combine an internal combustion engine with electric motors and batteries, and can have parallel or series configurations. CVTs may be beneficial for improving fuel efficiency in vehicles.
1) A continuously variable transmission (CVT) can change through an infinite number of gear ratios between maximum and minimum values without fixed steps.
2) There are several types of CVTs including pulley-based, toroidal, magnetic, hydrostatic, and cone-based transmissions.
3) CVTs provide advantages like constant acceleration, better fuel efficiency than manual transmissions, and allowing the engine to run at optimal RPMs regardless of vehicle speed.
This document discusses continuous variable transmissions (CVTs). It begins by explaining the basic function of a transmission to change the speed ratio between an engine and wheels. It then discusses problems with manual and automatic transmissions. CVTs are introduced as having benefits like providing optimal engine torque, no shift clunk, continuous ratio adjustment, better acceleration, and improved fuel efficiency. The main types of CVTs are then outlined as pulley-based, toroidal, and hydrostatic. Details are provided on the mechanisms and operation of each type. Control and modeling of CVTs are also briefly covered. Advantages are said to include decreased engine fatigue and improved efficiency over automatic transmissions, while disadvantages include limited torque and higher cost
The team created theoretical models of the continuously variable transmission (CVT) on the Cal Poly Baja car to improve performance. Their Adams model showed that increasing weight on the primary pulley results in faster expansion and quicker response time. Their Simulink model calculated that using the ideal CVT ratio would reduce the 0-100 ft time to under 5 seconds, improving their acceleration time by over 10%. Testing different ramp angles on the primary pulley also showed potential for obtaining the ideal ratio. Experimental validation was recommended over relying solely on analytical models.
CVT transmission can change seamlessly through an infinite number of effective gear ratios between maximum and minimum values giving jerk free driving experience.
In this presentation we mainly discuss about Variable-diameter pulley (VDP) and how basically it functions.
This document provides an overview of continuously variable transmissions (CVTs). It discusses the history and development of CVTs, the main types including pulley-based, cone, toroidal, and hydraulic CVTs. The advantages of CVTs are allowing the engine to run at an ideal RPM regardless of vehicle speed and fewer moving parts compared to automatic transmissions. Disadvantages include limited torque capacity and higher cost compared to manual transmissions. CVTs are commonly used in automobiles and are being developed for other applications like trucks, buses, and wind turbines.
The document discusses continuous variable transmissions (CVTs). It explains that CVTs provide an infinite number of gear ratios compared to traditional transmissions which have discrete gears. This allows the engine to run at optimal RPMs for efficiency. CVTs also provide seamless acceleration and improved fuel economy compared to automatic transmissions. While CVT technology is still developing, it is emerging as the preferred transmission type due to its advantages over other transmission options.
This document provides an overview of continuously variable transmissions (CVTs). It discusses the history of CVTs, including early sketches by Leonardo Da Vinci. It describes the main components and designs of CVTs, such as pulley-based, toroidal, and hydrostatic systems. The document outlines the advantages of CVTs, such as improved acceleration and fuel efficiency, as well as disadvantages like higher costs. It also discusses future applications of CVTs in electric vehicles and how the technology continues to develop.
This document provides information on continuously variable transmissions (CVTs). It begins with an introduction that defines CVTs as transmissions that can change seamlessly through an infinite number of gear ratios. It then covers the history, components, applications, advantages, and disadvantages of CVTs. The document concludes that the use of CVTs will likely continue increasing due to benefits like improved fuel efficiency and as automakers further develop the technology.
This document discusses continuously variable transmissions (CVTs). It provides a brief history of CVTs from their conception in 1490 to modern implementations. It then describes the basic components and types of CVTs including belt-driven systems. The document discusses the efficiency and losses associated with CVTs and strategies to improve efficiency. It compares CVTs to manual and automatic transmissions in terms of advantages like fuel economy and disadvantages like cost and reliability. The conclusion is that CVTs offer benefits for emission control and fuel economy and will likely become more widely adopted in the future.
This document appears to be a mini project report on continuously variable transmission (CVT) submitted by four students - Harshal Patil, Pooja Patil, Vijay Patil, and Priyanka Salve - at Vishwakarma Institute of Technology in Pune, India under the guidance of Professor S.P. Joshi. The report includes an introduction to CVTs, descriptions of their key components like pulleys and belts, an overview of different CVT types, and details about the students' own work on developing a CVT model. It aims to explain the technology and operation of CVTs through text, diagrams, and documentation of their hands-on project.
The document discusses continuously variable transmissions (CVTs). It provides an overview of CVTs, noting they vary the transmission ratio continuously and allow the engine to operate in its optimal power range. The main types of CVTs are described as metal push belt, toroidal drive, and cone designs. A brief history of CVTs is given, along with illustrations of how metal push belt CVTs work. Advantages like fuel efficiency and disadvantages like limited torque capacity are outlined. An example compares the acceleration of a car with a CVT versus manual transmission. A CATIA model of a CVT is shown along with component details.
The document discusses continuous variable transmissions (CVTs). It explains that CVTs provide infinite gear ratios between a minimum and maximum rather than distinct gears. This allows the engine to constantly operate at the ideal RPM for better fuel efficiency and acceleration without jerks between gears. CVTs also have fewer moving parts, wider ratio ranges, and are simpler than traditional automatic transmissions while providing constant acceleration. The document predicts CVTs will become more prominent as the technology further develops.
PPT ON CONTINUOUSLY VARIABLE TRANSMISSION CVT by Pukhraj Palariyapukhraj palariya
The document presents information on continuously variable transmissions (CVTs). It discusses how CVTs provide infinite gear ratios compared to conventional transmissions with discrete ratios. CVTs use a variable-diameter pulley system to seamlessly vary the transmission ratio based on engine speed. This allows the engine to stay in the optimal power band for efficiency. CVTs provide benefits like improved fuel economy and acceleration performance over manual and automatic transmissions. While more expensive initially, CVT technology is improving and allowing vehicles to meet stricter emissions standards. CVTs are expected to become more widely adopted in the future.
The document discusses the history and operation of continuously variable transmissions (CVTs). It notes that Da Vinci first sketched the concept of a CVT in 1490. Modern CVTs were introduced in cars starting in the 1950s and became more common in the 2000s. A CVT uses a pulley system with two variable-diameter pulleys connected by a push belt to provide an infinite range of gear ratios. This allows the engine to operate at optimal speeds for efficiency. The CVT's smooth acceleration and constant engine speed are advantages over traditional automatic and manual transmissions.
This document discusses the cone ring traction drive, a type of continuously variable transmission (CVT). It begins with an abstract that introduces the CVT and its advantages over other transmission types. It then discusses the need for the study, objectives, basic characteristics and principles of operation of the cone ring traction drive CVT. Key advantages are that it provides infinite gear ratios, allows the engine to run at peak efficiency, and operates smoothly without gear changes. The document outlines the methodology, including different types of CVTs and the specific design of the cone ring traction drive. Applications are in agricultural equipment, power tools, automobiles and motorcycles. The conclusion restates that the CVT improves fuel efficiency by allowing variable engine speeds.
The document discusses the transmission system of an automobile. It describes the purpose of a transmission as sending power from the engine to the drive wheels. It then discusses the main types of transmissions, focusing on continuously variable transmissions (CVTs). CVTs allow for infinite gear ratios between the engine and wheels for better acceleration and fuel efficiency. The document outlines the key components of a transmission system, including the flywheel, clutch, gearbox, propeller shaft, differential, axles and gears. It provides details on specific parts like the purpose of a differential and how gear ratios are calculated.
Power Transmission units in agricultural Tractors and their design conceptschelpuri Ramu
Power Transmission Units in Agricultural Tractors and their Design Concepts
1. The power transmission system in agricultural tractors functions to transmit power from the engine to the rear wheels, reduce the engine speed for field operations, and allow altering the speed ratio to suit field conditions.
2. Common types of gears used include helical, spur, and bevel gears. Gearboxes include sliding mesh, constant mesh, and synchromesh types. Planetary gear systems are becoming more common for the final drive due to their compact size and even load distribution.
3. Typical gear reduction ratios range from 1:175 for lower gears to 1:12 for higher gears. Design considerations for gearboxes include minimizing sizes, using
Design and Analysis of Drive System with Slip Ring Induction Motor for Electr...IJPEDS-IAES
The use of Squirrel Cage Motor for Traction has revolutionised the motive power of a Locomotive. The Asynchronous Motor is rugged, has high starting Torque, very smooth Voltage and Speed control as compared to a DC Series Motor. When looking at the Traction perspective, a Wound Rotor Induction Motor can be an alternative to the Squirrel Cage Motor as it has higher starting Torque at lower starting current and better efficiency than a Squirrel Cage Motor. The Slip Power Recovery scheme also plays a proactive role as there can be substantial savings of energy in case of a Wound Rotor Induction Motor as the Slip Power recovered can be used to drive the Auxiliary Loads of the Locomotive and also for powering the trailing Passenger Cars. A detailed design and analysis of a Drive System with Wound Rotor Induction Motor for Electric Traction is presented in this Research Paper.
This document discusses the fabrication of a continuously variable transmission (CVT) operated motorcycle. It begins with background on CVT technology, noting its advantages over traditional transmissions like fuel efficiency and smooth shifting. It then describes the specific CVT design for the motorcycle, using two variable diameter pulleys connected by a metal belt, with one pulley on the engine crankshaft and the other on the drive wheel. Drawings and descriptions of the fabricated CVT components and their operation are provided. The objectives of the CVT motorcycle design are given as providing a gearless transmission that varies ratios continuously for optimal engine efficiency. Prior research on CVT technology is also reviewed.
The constant rise in fuel prices on a day to day basis, maximum performance with minimum compromise on the front of fuel economy and emissions is highly desirable and expected from a vehicle’s transmission system. These friction drive CVTs were common in automotive use until engines capable of producing higher torques became common and necessitated the move to geared, fixed-ratio transmissions capable of high torque transfer and having better wear characteristics than friction dependent CVTs. Only in the past few years, with the advent of advanced materials and technology, have friction dependent CVTs returned to commercial application in the automotive industry. To provide a foundation and motivation for the research presented, this chapter first presents a definition of a continuously variable transmission.
This document provides an overview of continuously variable transmissions (CVTs) and hybrid electric vehicles (HEVs). It discusses the history and development of CVTs, including early inventions. The key components of CVTs are described, including the primary and secondary clutches and different types of belts. The document explains how CVTs work by varying the gear ratio through movement of the sheaves. Research and applications of CVTs are expanding, and they are beginning to be used more widely in vehicles. Hybrid vehicles combine an internal combustion engine with electric motors and batteries, and can have parallel or series configurations. CVTs may be beneficial for improving fuel efficiency in vehicles.
1) A continuously variable transmission (CVT) can change through an infinite number of gear ratios between maximum and minimum values without fixed steps.
2) There are several types of CVTs including pulley-based, toroidal, magnetic, hydrostatic, and cone-based transmissions.
3) CVTs provide advantages like constant acceleration, better fuel efficiency than manual transmissions, and allowing the engine to run at optimal RPMs regardless of vehicle speed.
This document discusses continuous variable transmissions (CVTs). It begins by explaining the basic function of a transmission to change the speed ratio between an engine and wheels. It then discusses problems with manual and automatic transmissions. CVTs are introduced as having benefits like providing optimal engine torque, no shift clunk, continuous ratio adjustment, better acceleration, and improved fuel efficiency. The main types of CVTs are then outlined as pulley-based, toroidal, and hydrostatic. Details are provided on the mechanisms and operation of each type. Control and modeling of CVTs are also briefly covered. Advantages are said to include decreased engine fatigue and improved efficiency over automatic transmissions, while disadvantages include limited torque and higher cost
The team created theoretical models of the continuously variable transmission (CVT) on the Cal Poly Baja car to improve performance. Their Adams model showed that increasing weight on the primary pulley results in faster expansion and quicker response time. Their Simulink model calculated that using the ideal CVT ratio would reduce the 0-100 ft time to under 5 seconds, improving their acceleration time by over 10%. Testing different ramp angles on the primary pulley also showed potential for obtaining the ideal ratio. Experimental validation was recommended over relying solely on analytical models.
CVT transmission can change seamlessly through an infinite number of effective gear ratios between maximum and minimum values giving jerk free driving experience.
In this presentation we mainly discuss about Variable-diameter pulley (VDP) and how basically it functions.
This document provides an overview of continuously variable transmissions (CVTs). It discusses the history and development of CVTs, the main types including pulley-based, cone, toroidal, and hydraulic CVTs. The advantages of CVTs are allowing the engine to run at an ideal RPM regardless of vehicle speed and fewer moving parts compared to automatic transmissions. Disadvantages include limited torque capacity and higher cost compared to manual transmissions. CVTs are commonly used in automobiles and are being developed for other applications like trucks, buses, and wind turbines.
The document discusses continuous variable transmissions (CVTs). It explains that CVTs provide an infinite number of gear ratios compared to traditional transmissions which have discrete gears. This allows the engine to run at optimal RPMs for efficiency. CVTs also provide seamless acceleration and improved fuel economy compared to automatic transmissions. While CVT technology is still developing, it is emerging as the preferred transmission type due to its advantages over other transmission options.
This document provides an overview of continuously variable transmissions (CVTs). It discusses the history of CVTs, including early sketches by Leonardo Da Vinci. It describes the main components and designs of CVTs, such as pulley-based, toroidal, and hydrostatic systems. The document outlines the advantages of CVTs, such as improved acceleration and fuel efficiency, as well as disadvantages like higher costs. It also discusses future applications of CVTs in electric vehicles and how the technology continues to develop.
This document provides information on continuously variable transmissions (CVTs). It begins with an introduction that defines CVTs as transmissions that can change seamlessly through an infinite number of gear ratios. It then covers the history, components, applications, advantages, and disadvantages of CVTs. The document concludes that the use of CVTs will likely continue increasing due to benefits like improved fuel efficiency and as automakers further develop the technology.
This document discusses continuously variable transmissions (CVTs). It provides a brief history of CVTs from their conception in 1490 to modern implementations. It then describes the basic components and types of CVTs including belt-driven systems. The document discusses the efficiency and losses associated with CVTs and strategies to improve efficiency. It compares CVTs to manual and automatic transmissions in terms of advantages like fuel economy and disadvantages like cost and reliability. The conclusion is that CVTs offer benefits for emission control and fuel economy and will likely become more widely adopted in the future.
This document appears to be a mini project report on continuously variable transmission (CVT) submitted by four students - Harshal Patil, Pooja Patil, Vijay Patil, and Priyanka Salve - at Vishwakarma Institute of Technology in Pune, India under the guidance of Professor S.P. Joshi. The report includes an introduction to CVTs, descriptions of their key components like pulleys and belts, an overview of different CVT types, and details about the students' own work on developing a CVT model. It aims to explain the technology and operation of CVTs through text, diagrams, and documentation of their hands-on project.
The document discusses continuously variable transmissions (CVTs). It provides an overview of CVTs, noting they vary the transmission ratio continuously and allow the engine to operate in its optimal power range. The main types of CVTs are described as metal push belt, toroidal drive, and cone designs. A brief history of CVTs is given, along with illustrations of how metal push belt CVTs work. Advantages like fuel efficiency and disadvantages like limited torque capacity are outlined. An example compares the acceleration of a car with a CVT versus manual transmission. A CATIA model of a CVT is shown along with component details.
The document discusses continuous variable transmissions (CVTs). It explains that CVTs provide infinite gear ratios between a minimum and maximum rather than distinct gears. This allows the engine to constantly operate at the ideal RPM for better fuel efficiency and acceleration without jerks between gears. CVTs also have fewer moving parts, wider ratio ranges, and are simpler than traditional automatic transmissions while providing constant acceleration. The document predicts CVTs will become more prominent as the technology further develops.
PPT ON CONTINUOUSLY VARIABLE TRANSMISSION CVT by Pukhraj Palariyapukhraj palariya
The document presents information on continuously variable transmissions (CVTs). It discusses how CVTs provide infinite gear ratios compared to conventional transmissions with discrete ratios. CVTs use a variable-diameter pulley system to seamlessly vary the transmission ratio based on engine speed. This allows the engine to stay in the optimal power band for efficiency. CVTs provide benefits like improved fuel economy and acceleration performance over manual and automatic transmissions. While more expensive initially, CVT technology is improving and allowing vehicles to meet stricter emissions standards. CVTs are expected to become more widely adopted in the future.
The document discusses the history and operation of continuously variable transmissions (CVTs). It notes that Da Vinci first sketched the concept of a CVT in 1490. Modern CVTs were introduced in cars starting in the 1950s and became more common in the 2000s. A CVT uses a pulley system with two variable-diameter pulleys connected by a push belt to provide an infinite range of gear ratios. This allows the engine to operate at optimal speeds for efficiency. The CVT's smooth acceleration and constant engine speed are advantages over traditional automatic and manual transmissions.
This document discusses the cone ring traction drive, a type of continuously variable transmission (CVT). It begins with an abstract that introduces the CVT and its advantages over other transmission types. It then discusses the need for the study, objectives, basic characteristics and principles of operation of the cone ring traction drive CVT. Key advantages are that it provides infinite gear ratios, allows the engine to run at peak efficiency, and operates smoothly without gear changes. The document outlines the methodology, including different types of CVTs and the specific design of the cone ring traction drive. Applications are in agricultural equipment, power tools, automobiles and motorcycles. The conclusion restates that the CVT improves fuel efficiency by allowing variable engine speeds.
The document discusses the transmission system of an automobile. It describes the purpose of a transmission as sending power from the engine to the drive wheels. It then discusses the main types of transmissions, focusing on continuously variable transmissions (CVTs). CVTs allow for infinite gear ratios between the engine and wheels for better acceleration and fuel efficiency. The document outlines the key components of a transmission system, including the flywheel, clutch, gearbox, propeller shaft, differential, axles and gears. It provides details on specific parts like the purpose of a differential and how gear ratios are calculated.
Power Transmission units in agricultural Tractors and their design conceptschelpuri Ramu
Power Transmission Units in Agricultural Tractors and their Design Concepts
1. The power transmission system in agricultural tractors functions to transmit power from the engine to the rear wheels, reduce the engine speed for field operations, and allow altering the speed ratio to suit field conditions.
2. Common types of gears used include helical, spur, and bevel gears. Gearboxes include sliding mesh, constant mesh, and synchromesh types. Planetary gear systems are becoming more common for the final drive due to their compact size and even load distribution.
3. Typical gear reduction ratios range from 1:175 for lower gears to 1:12 for higher gears. Design considerations for gearboxes include minimizing sizes, using
Design and Analysis of Drive System with Slip Ring Induction Motor for Electr...IJPEDS-IAES
The use of Squirrel Cage Motor for Traction has revolutionised the motive power of a Locomotive. The Asynchronous Motor is rugged, has high starting Torque, very smooth Voltage and Speed control as compared to a DC Series Motor. When looking at the Traction perspective, a Wound Rotor Induction Motor can be an alternative to the Squirrel Cage Motor as it has higher starting Torque at lower starting current and better efficiency than a Squirrel Cage Motor. The Slip Power Recovery scheme also plays a proactive role as there can be substantial savings of energy in case of a Wound Rotor Induction Motor as the Slip Power recovered can be used to drive the Auxiliary Loads of the Locomotive and also for powering the trailing Passenger Cars. A detailed design and analysis of a Drive System with Wound Rotor Induction Motor for Electric Traction is presented in this Research Paper.
This document discusses the fabrication of a continuously variable transmission (CVT) operated motorcycle. It begins with background on CVT technology, noting its advantages over traditional transmissions like fuel efficiency and smooth shifting. It then describes the specific CVT design for the motorcycle, using two variable diameter pulleys connected by a metal belt, with one pulley on the engine crankshaft and the other on the drive wheel. Drawings and descriptions of the fabricated CVT components and their operation are provided. The objectives of the CVT motorcycle design are given as providing a gearless transmission that varies ratios continuously for optimal engine efficiency. Prior research on CVT technology is also reviewed.
The constant rise in fuel prices on a day to day basis, maximum performance with minimum compromise on the front of fuel economy and emissions is highly desirable and expected from a vehicle’s transmission system. These friction drive CVTs were common in automotive use until engines capable of producing higher torques became common and necessitated the move to geared, fixed-ratio transmissions capable of high torque transfer and having better wear characteristics than friction dependent CVTs. Only in the past few years, with the advent of advanced materials and technology, have friction dependent CVTs returned to commercial application in the automotive industry. To provide a foundation and motivation for the research presented, this chapter first presents a definition of a continuously variable transmission.
This document summarizes research on continuously variable transmissions (CVTs). It discusses the basic components and operation of belt-driven and chain-driven CVTs. The document outlines the history and development of CVTs. It notes advantages like improved fuel efficiency and performance over traditional transmissions. Challenges in earlier CVT designs are described, such as belt slipping. The document discusses ongoing research focused on CVT control systems to optimize performance and efficiency. Different types of CVT control strategies, including ratio control and classical vs advanced control, are also summarized.
Drivetrain was designed and manufacture in such a way that it provides good acceleration, top speed and is reliable on different terrains. To obtain an infinite range of gear ratios so as to obtain the highest torque and as well reach the maximum speed, a CVT along with a self-designed auxiliary reduction gearbox was incorporated. Also driver comfort and fuel economy were include by using CVT.
This document discusses various transmission systems used in hybrid electric vehicles (HEVs). It describes manual, automatic, and automatic manual transmissions. It also covers continuously variable transmissions (CVTs), electronic CVTs (e-CVTs), and dedicated hybrid transmissions. CVTs provide an infinite number of gear ratios by varying the diameter of two cone pulleys connected by a belt or chain. Dedicated hybrid transmissions combine an electric motor and gasoline engine. Types include parallel, series, and plug-in hybrid configurations. The document also briefly discusses differentials which allow wheels to spin at different speeds during turns.
Latest Transmission Technologies In Passenger Cars- A ReviewIRJET Journal
This document reviews latest transmission technologies in passenger cars. It discusses the history and purpose of transmission systems, including manual and automatic transmissions. The key points covered include:
- Automatic transmissions provide more convenience than manual transmissions by shifting gears automatically, but are less fuel efficient due to losses in the torque converter and hydraulic actuators.
- Electronic control transmissions (ECT) use sensors and an electronic control unit to control shifting instead of a hydraulic system. This allows for smoother gear changes.
- The electronic control unit programs optimal shift patterns and controls transmission components like solenoid valves, shift valves, and the lock-up clutch based on vehicle speed and throttle position sensor inputs.
- Dri
IRJET- Survey on Gear Shifting Strategies in the VehiclesIRJET Journal
The document discusses gear shifting strategies in vehicles. It provides an overview of manual and automatic transmissions. For manual transmissions, the driver operates the clutch and shifts gears. Automatic transmissions electronically change gears based on speed without driver input. The document also reviews recent research on improving manual shift quality and developing automated manual transmissions. It describes how automated systems reduce effort and ensure smooth gear changes but are more complex than manual. Electromagnetic systems are presented as an alternative for situations requiring frequent shifting.
Hydrostatic Continuous Variable Power Transmission Drive for Two wheelers usi...ijsrd.com
Power transmission is an extremely important factor for the automotive industry today. In vehicles, the power transmission system is the major source of energy losses. This is an intentionally compact review for a module addressing basic Fluid Mechanics for incompressible fluids within the context of Applied Energy Systems. Rather than attempting to cover Fluid Mechanics in a very broad and general way, two practical areas are selected in the use of fluids, hydrostatic power transmission systems and the flow of fluids through pipes and fittings. Thus readers are prepared for applying the same and similar principles to a much broader range of practical applications in the future. The present review work relates to a rotary pump and motor transmission system, which permits a change in ratio between the speed of the driver and driven shafts from direct drive to neutral position. This transmission, which may be adopted for many uses, such as vehicles and machine tools, is endowed with the utmost ease of operation even under load, is of a simple and rugged construction and offers safety of operation even after an extended use.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.t
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Analysis, Design and Application of Continuously Variable Transmission (CVT)
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Analysis, Design and Application of Continuously Variable
Transmission (CVT)
Vishnu Seelan
( B.Tech. Mechanical Engineering, Department of Mechanical Engineering, School of Engineering, Cochin
University of Science and Technology-CUSAT, Kochi, India)
ABSTRACT
Continuously Variable Transmission (CVT) offers a continuum of gear ratios between desired limits. This
allows the engine to operate more time in the optimum range. In contrast, traditional automatic and manual
transmissions have several fixed transmission ratios forcing the engine to operate outside the optimum range.
The need for a transmission system and the working principle of CVT has been discussed in depth. An attempt
has been made to understand the contribution of Hydraulic Actuators, which is an integral part of a CVT.
Furthermore, the question of how and why a Torque Converter has effectively replaced a conventional clutch
has been answered. The materials used, constructional aspects and stress analysis of the belt has been discussed
in detail. A graphical comparison of fuel efficiency between a manual transmission and a CVT in different high
end vehicles is included. Recent developments in clamping force control for the push belt Continuously
Variable Transmission (CVT) have resulted in increased efficiency in combination with improved robustness.
Current control strategies attempt to prevent macro slip between elements and pulleys at all times for maximum
robustness.
Keywords - Belt Design, CVT, Hydraulic Actuators, Torque Converter, Transmission
I. INTRODUCTION
A Continuously Variable Transmission (CVT)
has been around for more than a 100 years, but has
only recently found its way into automotive
applications. The overwhelming majority of
transmissions in road going vehicles are either
manual or conventional automatic in design. These
transmissions use meshing gears that give discrete
ratio steps between engine and the vehicle speed.
However, alternative designs exist that can transmit
power and simultaneously give a step less change of
ratio; in other words a Continuously Variable
Transmission. Continuously Variable Transmission is
a type of automatic transmission that provides an
uninterrupted range of speed ratios, unlike a normal
transmission that provides only a few discrete ratios.
However, until recently it was reserved for
industrial applications like running lathes or light
duty drill presses. But with the introduction of
improved materials, such as high density belts,
advanced hydraulics and more recently, high speed
sensors and microprocessors, the stage was set for
CVT’s rise in the automobile arena.
Many small tractors for home and garden use
have simple rubber belt CVTs. For example, the John
Deere Gator lines of small utility vehicles use a belt
with a conical pulley system. They can deliver an
abundance of power and can reach speeds of 10–15
mph (16–24 km/h), all without need for a clutch or
shifting gears. Nearly all snowmobiles, old and new,
and motor scooters use CVTs, typically the rubber
belt/variable pulley variety.
II. TRANSMISSION
The understanding of the meaning and function
of a simple transmission is a pre-requisite to the
CVT.
The transmission adapts the output of the
internal combustion engine to the drive wheels. Such
engines need to operate at a relatively high rotational
speed, which is inappropriate for starting, stopping,
and slower travel. The transmission reduces the
higher engine speed to the slower wheel speed,
increasing torque in the process.
The transmission will generally be connected to
the crankshaft of the engine. The output of the
transmission is transmitted via driveshaft to one or
more differentials, which in turn, drive the wheels.
The need for a transmission in an automobile is a
consequence of the characteristics of the internal
combustion engine. Engines typically operate over a
range of 600 to about 7000 revolutions per minute
(though this varies, and is typically less for diesel
engines), while the car's wheels rotate between 0 rpm
and around 1800 rpm. Often the greatest torque is
required when the vehicle is moving from rest or
traveling slowly, while maximum power is needed at
high speed. Therefore, a system that transforms the
engine's output so that it can supply high torque at
low speeds, but also operate at highway speeds with
RESEARCH ARTICLE OPEN ACCESS
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the motor still operating within its limits, is required.
Transmissions perform this transformation.
The structural aspects of the transmission,
predominantly the casting, often contribute
significantly to the structure of the power train and
the vehicle as a whole. This is important when it
comes to engineering for the lowest noise and
vibration. The stiffness of the power train assembly
itself is important in determining the magnitude and
frequency of the vibrations at the source (the engine).
II.1 OPTIMUM RPM RANGE
An automobile engine runs at its best efficiency
at a certain Revolutions Per Minute (RPM) range and
it is the transmission's function to make sure that the
power is delivered to the wheels while keeping the
engine speed within this optimum range. The
transmission accomplishes this through various gear
combinations.
In addition to the various forward gears, a
transmission also has a Neutral stance which
disconnects the engine from the drive wheels, and the
Reverse stance, which causes the drive wheels to turn
in the opposite direction thereby reversing the
direction of the car.
III. CONTINUOUSLY VARIABLE
TRANSMISSION (CVT)
A Continuously Variable Transmission (CVT)
is a transmission that can change steplessly through
an infinite number of effective gear ratios between
maximum and minimum values.
On the other hand, the conventional mechanical
transmissions offer only a fixed set of gear ratios.
The unique feature of a CVT allows the driving shaft
to maintain a constant angular velocity over a range
of output velocities. This property produces better
fuel efficiency compared to other transmissions by
allowing the engine to run at its most efficient
revolutions per minute (RPM) for a range of
automobile speeds.
Another possibility is that a CVT can be used to
achieve the best automobile performance by
permitting the engine to revolve at the RPM at which
it produces the peak power. This is normally higher
than the RPM that achieves peak efficiency.
The use of CVT makes the engine to go from an
idle to a pre-programmed rpm immediately, so the
engine input is constant and then varies the output
speed for smooth, seamless acceleration. CVTs
enable power application without any jerk.
The continuously variable transmission (CVT)
has been around as long as the automobile. Engineers
have always recognized its theoretical advantage over
the multi ratio gearbox. A CVT enables the engine to
run at its most fuel-efficient or most power-efficient
speed while driving the vehicle at any speed desired.
With a CVT, engine speed and vehicle speed are
no longer connected by a series of discrete ratios.
Instead, they can function independently across a
wide and step less band according to engine
characteristics and performance requirements. The
advantages of this infinite ratio selectivity are
enormous. Most obvious in the IC engine application
is that the engine can be loaded into its most fuel-
efficient region at cruising speeds, then allowed to
accelerate into its region of greatest output when
peak power is needed, regardless of vehicle speed.
Practical problems have consistently plagued the
design, but the CVT is now coming of age.
III.1. COMPONENTS OF A CVT
1. A high power/density belt.
2. A set of Cone pulleys.
3. Hydraulic Actuator.
4. Mechanical torque sensor.
5. Microprocessor.
6. Torque Converter or Multi-layered
clutch (replacing conventional
clutches).
IV. WORKING PRINCIPLE OF A CVT
A Continuously Variable Transmission operates
by varying the working diameter of the two main
pulleys in the transmission.
Fig(1): Working of CVT.
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The pulleys have V-shaped grooves on which the
connecting belt is mounted. One side of the pulley is
fixed; the other side is moveable, operated by a
hydraulic actuator. The hydraulic actuator can
increase or decrease the amount of space between the
two sides of the pulley. This makes the belt to ride
lower or higher along the inner walls of the pulley,
depending on driving conditions, thereby changing
the gear ratio. This action is infinitely variable with
no “steps” in between. Thus a CVT can maintain the
engine in its optimum rpm range, in turn boosting the
efficiency and gas Mileage.
As explained above the two pulley widths are
adjusted by oil pressure in the hydraulic actuator
which responds to position of the throttle, speed, and
other conditions, which are sensed by
microprocessors & other sensors.
IV.1. HYDRAULIC ACTUATORS
A Hydraulic Actuator (also called a linear
hydraulic motor) is a mechanical device that is used
to give a unidirectional force through a unidirectional
stroke.
Fig(2): A Cut Away of a Hydraulic Actuator.
Hydraulic Actuators get their power from
pressurized hydraulic fluid, which is typically oil.
The hydraulic cylinder consists of a cylinder barrel,
in which a piston connected to a piston rod moves
back and forth. The barrel is closed on each end by
the cylinder bottom (also called the cap end) and by
the cylinder head where the piston rod comes out of
the cylinder. The piston has sliding rings and seals.
The piston divides the inside of the cylinder in two
chambers - the bottom chamber (cap end) and the
piston rod side chamber (rod end). The hydraulic
pressure acts on the piston to do linear work and
motion.
The piston rod also has mounting attachments to
connect the cylinder to the object or machine
component that it is pushing/pulling.
A hydraulic cylinder is the actuator or "motor"
side of this system. The "generator" side of the
hydraulic system is the hydraulic pump which brings
in a fixed or regulated flow of oil to the bottom side
(.i.e. bottom chamber) of the hydraulic cylinder, to
move the piston rod upwards. The piston pushes the
oil in the other chamber back to the reservoir. If we
assume that the oil pressure in the piston rod chamber
is approximately zero, the force F on the piston rod
equals the pressure P in the cylinder times the piston
area A:
Push Force, (1)
The piston moves downwards if oil is pumped into
the piston rod side chamber and the oil from the
bottom chamber area flows back to the reservoir
without pressure.
The fluid pressure in the piston rod area chamber is:
(Pull Force) / (piston area - piston rod area):
(2)
Thus the Pull Force, Fp = P(Ap – Ar)(3)
Where P is the fluid pressure, Fp is the pulling force,
Ap is the piston face area and Ar is the rod cross-
section area.
IV.2. TORQUE CONVERTER
An engine is connected to a transmission by way
of a clutch. Without this connection, a car would not
be able to come to a complete stop without killing the
engine. But cars with CVT have no clutch that
disconnects the transmission from the engine.
Instead, they use an amazing device called a torque
converter.
As shown in the figure below, there are four
components inside the very strong housing of the
torque converter:
Pump
Turbine
Stator
Transmission fluid
The housing of the torque converter is bolted to
the flywheel of the engine, so it turns at whatever
speed the engine is running at. The fins that make up
the pump of the torque converter are attached to the
housing, so they also turn at the same speed as the
engine. The cutaway below shows how everything is
connected inside the torque converter.
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Fig(3): Torque Converter.
The pump inside a torque converter is a type of
centrifugal pump. As it spins, fluid is flung to the
outside, much as the spin cycle of a washing machine
flings water and clothes to the outside of the wash
tub. As fluid is flung to the outside, a vacuum is
created that draws more fluid in at the center.
The fluid then enters the blades of the turbine,
which is connected to the transmission. The turbine
causes the transmission to spin, which basically
moves your car. You can see in the graphic below
that the blades of the turbine are curved. This means
that the fluid, which enters the turbine from the
outside, has to change direction before it exits the
center of the turbine. It is this directional change
that causes the turbine to spin.
In order to change the direction of a moving
object, you must apply a force to that object. And
whatever applies the force that causes the object to
turn must also feel that force, but in the opposite
direction. So as the turbine causes the fluid to change
direction, the fluid causes the turbine to spin.
The fluid exits the turbine at the center, moving
in a different direction than when it entered. If we
look at the arrows in the figures (4) & (5) below, we
can see that the fluid exits the turbine moving
opposite the direction that the pump (and engine) is
turning. If the fluid were allowed to hit the pump, it
would slow the engine down, wasting power. This is
why a torque converter has a stator.
Fig(4):Pump.
Fig(5): Turbine.
Fig(6):Stator
The stator resides in the very center of the torque
converter. Its job is to redirect the fluid returning
from the turbine before it hits the pump again. This
dramatically increases the efficiency of the torque
converter.
The stator has a very aggressive blade design
that almost completely reverses the direction of the
fluid. A one-way clutch (inside the stator) connects
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the stator to a fixed shaft in the transmission (the
direction that the clutch allows the stator to spin is
noted in the fig(6) above). Because of this
arrangement, the stator cannot spin with the fluid -- it
can spin only in the opposite direction, forcing the
fluid to change direction as it hits the stator blades.
V. BELT DESIGN
As the belt is the highly stressed member, it must
be very strong and grip very well on the pulleys.
V.1. BELT MATERIALS
1. Rubber.
2. Steel.
3. Thin & high strength Metals.
The variable-diameter pulleys are the heart of a
CVT. Each pulley is made of two 20-degree cones
facing each other. A belt rides in the groove between
the two cones. V-belts are preferred if the belt is
made of rubber. V-belts get their name from the fact
that the belts bear a V-shaped cross section, which
increases the frictional grip of the belt.
In earlier applications of the CVT, the
transmissions have relied on high-density rubber
belts, which can slip and stretch, thereby reducing
their efficiency.
The introduction of new materials makes CVTs
even more reliable and efficient. One of the most
important advances has been the design and
development of metal belts to connect the pulleys.
These flexible belts are composed of several
(typically nine or 12) thin bands of steel that hold
together high-strength, bow-tie-shaped pieces of
metal. Metal belts don't slip and are highly durable,
enabling CVTs to handle more engine torque. They
are also quieter than rubber-belt-driven CVTs.
Fig(7): Metal Belt Design Layout.
Fig(8): Photograph of a Metal Belt.
Fig(9): Mounting a metal belt on the Pulley.
As shown in the figures(7), (8) & (9) above, a
CVT belt is constructed by stacking up 9 to 12 Steel
bands (called “Rings”) in the grooves on either sides
of a thin high strength metal known as the
“Element”.
Fig(10): Cross section of the Push belt/Pulley system.
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V.2. STRESS CONSIDERATIONS
Stepless shifting between the extreme LOW
(under drive) and OD (overdrive) ratios is achieved
by varying the pulley clamping forces and thereby
changing the axial position of the moveable pulley
sheaves, modifying the effective running radius.
During operation of the variator, the push-belt and
pulleys undergo cyclic (fatigue) loading. Stress levels
in the push-belt elements and pulleys are determined
by the applied pulley clamping forces, rotational
speeds, and torque levels. Experience has shown that
fatigue loading of the elements and pulleys is less
critical in practice than ring fatigue loading. The
push-belt rings are mainly subjected to bending and
tensile stresses (see Figure11 below). In general, the
bending stresses are determined by the applied
running radii (transmission ratio) and the ring
thickness. The tensile stresses are mainly determined
by the applied pulley clamping forces, rotational
speeds, and torque levels.
Fig(11): Push-belt loading (ring stresses, running
radii, pulley centre distance, ratio coverage).
A film of lubricant is applied to the pulleys. It
needs to be thick enough so that the pulley and the
belt never touch and it must be thin in order not to
waste power when each element dives into the
lubrication film. Additionally, the chain elements
stabilize about 12 steel bands. Each band is thin
enough so that it bends easily. If bending, it has a
perfect conical surface on its side. In the stack of
bands each band corresponds to a slightly different
gear ratio, and thus they slide over each other and
need oil between them.
CVT stands for continuously variable
transmission. This type of transmission allows for a
change in ratios without stopping or disengaging.
Most CVT's are friction drive, with some means of
varying the relative diameters of the driving
components while driving. These friction drive
transmissions are simple, but can only transmit a
limited amount of torque before the wheels start
slipping. There are some CVT's that use gears and
cranks that offer positive drive without a chance for
slippage, but these are much more complicated.
VI. ADVANTAGES OF CVT
1. CVTs provide unlimited gear ratios and
improved performance.
2. Pulleys and a belt inside the CVT seamlessly
change the gear ratios without any “shift shock”
or delay.
3. The infinite ratios help in maintaining a steady
cruising speed, reducing the fuel emissions and
thus improve fuel economy.
4. Due to its ability to change the ratios
continuously, a CVT helps to keep the engine in
its optimum rpm range, thereby increasing the
fuel efficiency.
5. The 2012 model of the Honda Jazz sold in the
UK actually claims marginally better fuel
consumption for the CVT version than the
manual version.
6. CVTs provide quicker acceleration than a
conventional automatic.
7. A key advantage of a CVT for a manufacturer is
that its production costs lesser than a
conventional multispeed automatic because it
uses fewer parts.
8. CVT eliminates the gear shifts of a manual
transmission and the accompanying rise and fall
of engine speed.
Fig(12):
0
2
4
6
8
10
fuel
consumpti
on[l/100k
m]
Honda
HR-V 1.6i
4WD
Subaru
R2 660R
Comparison Manual Transmission (MT)
versus CVT for a drive cycle.
Manual T
CVT
The Above Graph shows the Fuel Efficiency
comparison of the following vehicles:
1. Honda HR-V 1.6i 4WD
2. Honda Jazz 1.4i
3. Nissan Primera 2.0
4. Subaru R2 660R
5. Mercedes Benz A-class A200
7. Vishnu Seelan Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 3, ( Part -1) March 2015, pp.99-105
www.ijera.com 105 | P a g e
VII. LIMITATIONS OF CVT
1. CVTs use steel metal belts, which have less
torque transmitting capacity and thus a CVT
cannot be used in heavy vehicles. Its application
is limited to small vehicles.
2. Friction between the belt and the pulley causes
greater wear.
3. The transmission fluid is a little expensive.
VIII. HISTORY
1490 - Leonardo da Vinci sketches a stepless
continuously variable Transmission.
1886 - First toroidal CVT patent filed.
1935 - Adiel Dodge receives U.S. patent for toroidal
CVT.
1939 - Fully automatic transmission based on
planetary gear system introduced.
1958 - Daf (of the Netherlands) produces a CVT in a
car.
1989 - Subaru Justy GL is the first U.S. sold
production automobile to offer a CVT.
2002 - Saturn Vue(General Motors’ SUV) with a
CVT debuts.
2004- Ford begins offering a CVT.
IX. CONCLUSION
“A Continuously Variable Transmission or CVT
blends the ease of an automatic transmission with the
efficiency of a manual transmission.” This statement
made by the Honda Motors completely summarizes
the concept of CVT.
CVT is definitely a technology of the future with
its higher fuel efficiency, infinite gear ratios, lower
manufacturing costs, steady cruising speeds & better
acceleration capabilities.
This technology has found such wide
applications only recently. Thus most of us have to
get used to the dynamics of a CVT-equipped vehicle
for its better appreciation.
X. ACKNOWLEDGEMENT
I express my deep gratitude to almighty, the
supreme guide, for bestowing his blessings upon me
in my entire endeavor.
I would like to express my sincere thanks to Dr.
K.K. Saju, Head of the Department of Mechanical
engineering(SOE, CUSAT) for all his assistance. I
wish to express my deep sense of gratitude to Dr.
Tide P.S., Department of Mechanical
Engineering(SOE, CUSAT) who guided me
throughout my graduation. His overall direction and
guidance has been responsible for the successful
completion of my academic endeavors.
I am also indebt to all the faculty members of
Mechanical Engineering Department for their kind
co-operation. Finally, I would like to acknowledge
the assistance of all my friends in the process of
completing this work.
REFERENCES
[1] C.de Silva, M.Schultz (2002) “Kinematic
analysis & Design of a CVT” -University of
British Columbia.
[2] howstuffworks.com
[3] Ir. B. Pennings, Ir. M.D. Tran (2010)
“New CVT push-belt design” - journal for
Bosch Group.
[4] John M.Miller (2004), Propulsion Systems
for Hybrid Vehicles, Publisher: Institution of
Engineering & Technology.
[5] Nilabh Srivastava, Imtiaz Haque (2009)
“A review on belt & chain CVT: Dynamics
& Control” - University of North Carolina.
[6] wikipedia.com
[7] world.honda.com