Continuously Variable Transmission Research Articles

Tooth Contact Analysis of Herringbone Rack Gears of an Impulse Continuously Variable Transmission

Finite element based tooth contact analysis of a rack and pinion system of an impulse continuously variable transmission is performed in this study. The rack and pinion system are designed with involute profile herringbone tooth profiles. The involute profile herringbone tooth profile is a type of concave-convex pro-files, which can be used for heavy load conditions. A contact load distribution model of the rack gear with involute profile herringbone tooth profiles is devel-oped to analyze normal loads of any mashing position of the rack pinion system based on the minimum elastic potential energy theory. With the aim of improving the rack and pinion system design, the actual operation of gears under the terms of the three-dimensional tooth contact analysis is conducted. A rack gear with herringbone tooth profiles and a pinion are used to tooth contact analysis. Based on comparing the results of this analysis, a new type of rack gears with concave-convex involute tooth profile are advantages and disadvantages in terms of the contact stress.

Co-Design of CVT-Based Electric Vehicles

For an electric vehicle (EV) with a continuously variable transmission (CVT), a novel convex programming (CP)-based co-design method is proposed to minimize the total-cost-of-ownership (TCO). The integration of the electric machine (EM) and the CVT is the primary focus. The optimized system with co-design reduces the TCO by around 5.9% compared to a non-optimized CVT-based EV (based on off-the-shelf components) and by around 2% compared to the EV equipped with a single-speed transmission (SST). By taking advantage of the control and design freedom provided by the CVT, the optimal CVT, EM and battery sizes are found to reduce the system cost. It simultaneously finds the optimal CVT speed ratio and air-flow rate of the cooling system reducing the energy consumption. The strength of co-design is highlighted by comparing to a sequential design, and insights into the design of a low-power EV that is energy-efficient and cost-effective for urban driving are provided. A highly integrated EM-CVT system, which is efficient, low-cost and lightweight, can be expected for future EV applications.

A Comparative Study of Energy Consumption and Recovery of Autonomous Fuel-Cell Hydrogen–Electric Vehicles Using Different Powertrains Based on Regenerative Braking and Electronic Stability Control System

Today, with the increasing transition to electric vehicles (EVs), the design of highly energy-efficient vehicle architectures has taken precedence for many car manufacturers. To this end, the energy consumption and recovery rates of different powertrain vehicle architectures need to be investigated comprehensively. In this study, six different powertrain architectures—four independent in-wheel motors with regenerative electronic stability control (RESC) and without an RESC, one-stage gear (1G) transmission, two-stage gear (2G) transmission, continuously variable transmission (CVT) and downsized electric motor with CVT—were mathematically modeled and analyzed under real road conditions using nonlinear models of an autonomous hydrogen fuel-cell electric vehicle (HFCEV). The aims of this paper were twofold: first, to compare the energy consumption performance of powertrain architectures by analyzing the effects of the regenerative electronic stability control (RESC) system, and secondly, to investigate the usability of a downsized electrical motor for an HFCEV. For this purpose, all the numerical simulations were conducted for the well-known FTP75 and NEDC urban drive cycles. The obtained results demonstrate that the minimum energy consumption can be achieved by a 2G-based powertrain using the same motor; however, when an RESC system is used, the energy recovery/consumption rate can be increased. Moreover, the results of the article show that it is possible to use a downsized electric motor due to the CVT, and this powertrain significantly reduces the energy consumption of the HFCEV as compared to all the other systems. The results of this paper present highly significant implications for automotive manufacturers for designing and developing a cleaner electrical vehicle energy consumption and recovery system.

Electronic system of rubber belt electro-mechanical continuously variable transmission for motorcycle applications

This paper deals with the design of electronic system for changing the transmission ratio of a rubber belt electro-mechanical continuously variable transmission (CVT) for motorcycle applications. In this CVT, the rubber belt is used as a medium to transfer both the speed and torque from the input pulley to the output pulley based on contact friction force existed between the belt and both pulley surfaces. Each pulley set consists of one fixed and one sliding pulley sheaves. The axial position of the input sliding pulley sheave is detected using a two channel incremental rotary encoder and controlled by an electro-mechanical shifter system utilizing DC motor, actuator gear set and cam mechanism. The sliding sheave of the output pulley is axially pushed by contra spring to provide sufficient belt compression for preventing belt slip. The CVT ratio is changed by varying the input and output belt-pulley contact radii. It can be done by controlling the axial position of sliding input pulley sheave, the angular speeds of input and output pulleys are sensed using one channel incremental rotary encoders. By knowing these two speed values, the CVT ratio can be computed. The microcontroller system of Arduino is programmed to detect and control the axial position of the input sliding pulley sheave to regulate the CVT ratio. The experimental results show that the electronic system can perform the CVT ratio changes adequately.

Experimental study of transmission ratio changing mechanism for motorcycle applications

Transmission ratio change in today’s motor cycle rubber belt Continuously Variable Transmission (CVT) are based on centrifugal forces resulted from engine revolution. Compare to manual transmission, this kind of CVT needs higher engine revolution to start engaging the transmision ratio which in turn requiring more fuel consumption. A transmission ratio change concept based on an Electro-mechanical actuator consisting of cam, actuator gears and DC motor has been developed to eliminate the dependancy of transmission ratio on engine revolution. The DC motor rotates the cam through actuator gears. The rotation of the cam causes the primary movable pulley sheave to move in axial direction, which in turn changing the belt-pulley pitch radius and changing the transmission ratio. This research aims to design and implement an electronic measurement system based on Arduino Uno as a data acquisition system and Matlab/Simulink as a controller program to obtain the measurement data of primary pulley and secondary pulley speeds and primary pulley axial position. Based on these data, the transmission ratio can be determined and the relationship between transmission ratio and primary pulley posistion can then be obtained. For future development, these measurement data will be used as important references when developing and testing the transmission ratio controller programs.

Comparative study of different electric vehicle configurations in terms of energy consumption

In order to respect the new fleet-wide average emission regulations, recent studies show that car manufacturers produce an increased number of electric vehicles.For improving the dynamic performances of an electric vehicle while maintaining a low energy consumption, different solutions are used, such as the multi-speed transmission, or the continuously variable transmission (CVT). Another solution more advantageous than other EV typologies consists of a dual motor two speed direct drive, that implies each motor being connected with the final drive through a separate gear. The aim of this paper is to analyse the energy consumption and the overall transmission performance in different test cycles for a middle class with different configurations. The study was carried out by developing a model in a performant simulation environment. The obtained simulation results from the chosen configuration are compared in different test cycles in terms of energy consumption ratio (ECR) and vehicle speed fluctuation (VSF) with the ones from a direct drive EV and a two-gear transmission EV.

An Evaluation Method of Mode Switching Quality for Double-Belt Continuously Variable Transmission

In order to improve the transmission efficiency and carrying capacity of conventional single-belt continuously variable transmission (CVT), one new type of dual-belt CVT is proposed in this paper. Under the situation that this new dual-belt CVT should be switched between single- and dual-belt modes frequently according to driver’s intention and road conditions, so five objective evaluation indexes of mode switching quality for the dual-belt CVT are proposed, considering the aspects of vehicle power, comfort, and transmission durability comprehensively. Then, the objective evaluation model of mode switching quality is established by the BP neural network optimized by the genetic algorithm. It is found that the prediction results are consistent with the subjective evaluation. After analyzing the influence of the selected five evaluation indexes on the prediction results, it is obvious that these five evaluation indexes of mode switching quality for dual-belt CVT are reasonable.

Transmission systems in agricultural tractors marketed in Brazil

ABSTRACT: In a tractor, the transmission system transmits the power generated in the engine to the driving wheels, hydraulic systems, and power take-off (PTO). There are several types of transmission systems available in the Brazilian market ranging from the simplest to the most advanced. Therefore, the objective of this study was to verify the different types of transmission systems present in 228 models of agricultural tractors produced and marketed in Brazil during 2019. The tractor models were grouped based on the engine power and the transmission systems were classified as sliding, partially synchronized, synchronized, semi powershift, full powershift, and continuously variable transmission (CVT). According to this classification, it was found that most tractors belonged to Class III (51.5-73.5 kW) with 66 models in total. However, even with continuous modernization in this field and with tractors becoming increasingly independent from the operator, 66% of transmission systems are still mechanical. However, CVT systems, which are available only in tractors with an engine power above 117.7 kW, are expected to be equipped on less powerful tractors in the coming decades.

Design and development of longitudinal vehicle dynamics for an All-terrain vehicle

Design and development of maximum efficiency in the longitudinal axis of vehicle dynamics for an ATV have been carried out by developing an optimum Transmission system in accordance with other subsystems viz Braking and Suspension. The design parameters of suspension, braking, and transmission systems has been calculated using MATLAB. 3D Computer Aided Designing, simulation, and validation of all the components have been carried out in Solidworks, ANSYS & MATLAB respectively. To achieve an optimum gear ratio considering factors - top speed and acceleration and to maximize the efficiency of longitudinal vehicle dynamics, optimum design parameters have been considered for suspension, braking, and transmission systems on an All-Terrain Vehicle. Acceleration and Braking are one of the most both essential parameters for longitudinal vehicle dynamics. Gaged GX9 model continuously variable transmission (CVT) has been used as an integral component for the powertrain of the All-terrain vehicle and the velocity of the vehicle is considered around 58 to 60 kph (~16 to 17 m/sec). Further a reduction gearbox of a ratio of 8.124 has been used for efficient transmission of torque from the engine to the wheels. Temperature plots and computational fluid dynamics plots have been obtained for the brake disc to observe the thermal dissipation behavior of the braking system and similarly, thermal plots have been obtained for the continuous variable transmission made of aluminum.

Calculation, design and analysis of two stage single speed gearbox for all terrain vehicle for baja sae

In modern era, ATVs got immense support from the audience and critics due to its complexity due to which ATVs require to work in extreme conditions that required a massive amount of analysis and testing. In this paper, we focused on the theoretical experiment of designing, calculation, and analysis of gearbox that will are used in BAJA SAE. The gearbox designed was used in BAJA SAE CALIFORNIA 2019 by Team JAABAZ. The paper describes the calculation for modern helical gears, compact shafts, and gearbox with excellent analysis. The gearbox was custom designed from every aspect for proper integration in the ATV with high efficiency. The gearbox met all the BAJA SAE International rules [1]. The gearbox will be integrated with continuously variable transmission (CVT) and coupled with UV joint to transfer torque to wheels. The gearbox is considered with efficient tolerance and had been working for 2-years. The gearbox was designed by using SOLIDWORKS for CAD design and ANSYS for analysis of the gearbox. The gearbox is designed to reduce the weight and was designed to handle in extreme conditions for approx. 2 years.

The Specifics of Calculating the Efficiency of the Continuously Variable Mechanical Transmission with Oscillatory Movement of Internal Links and Force Function Control

The paper discusses the energy flow in the continuously variable mechanical transmission with oscillatory movement of internal links and force function control. It is proposed to treat the potential energy of the twisted torsion bars, which is transferred back to the drive shaft, as useful. The formula for calculating the transmission efficiency, taking into account the return of energy flow back to the motor, hysteresis losses, and energy dissipation in the mechanical rectifier while taking up the free play, is given. When calculating the efficiency of the continuously variable mechanical transmission, it is suggested to take into consideration the clearances in the rectifier and kinematic pairs using ‘kinematic efficiency’. The examples of measured and calculated transmission efficiency in the ‘stop’ mode are given.

Determining the Drive Power of the System Controlling the Vibration Amplitude of the Rectifiers for the Continuously Variable Mechanical Transmission with Internal Force Functions

The article discusses the choice of the power and type of the drive motor for the system controlling the vibration amplitude of the rectifier rocker arms of the continuously variable mechanical transmission, intended for use on a motor vehicle. Formulas for calculating the required torque and rotational speed of the drive motor with a planetary differential control gear are given. It is shown that the use of an electrohydraulic drive provides the required speed and power operation of the control system. The results of the system testing are presented.

Design and Modeling of an Impulse Continuously Variable Transmission with a Rotational Swashplate

A novel mechanical impulse continuously variable transmission (ICVT) is developed to provide continuously variable speed ratios and smooth acceleration for drivetrains based on a rotational swashplate, and its design principle is illustrated. A swashplate-guide linkage mechanism is used in the ICVT; the speed ratio of the ICVT is changed with the swirl angle of the rotational swashplate. A slider–linkage system, whose mo-tion is controlled by a speed-regulating handle, is used to adjust the swirl angle of the swashplate. A planetary gear system converts the regulated rotational speed of the swashplate to the output shaft of the ICVT. The speed range of the ICVT can be scaled up by coupling planetary gear sys-tems with different speed ratios. Overrunning clutches are used to rectify the rotational speed from the swashplate-guide linkage mechanism to ob-tain the output speed of the ICVT. Since the rotational swashplate can in-troduce large impulse rates of the instantaneous speed ratio, a connecting linkage is used to reduce the impulse rate and unbalanced inertial forces of the ICVT. Experimental tests of the output speed of the ICVT with four guide linkages verify the feasibility of the design and operation perfor-mance of the ICVT.

Dynamics of Heaving Buoy Wave Energy Converters with a Stiffness Reactive Controller

Heaving buoy wave energy converters (WEC) are floating oscillators, commonly modeled as single-degree-of-freedom vibrating systems. As the wave frequencies change according to the sea state, these devices must be controlled to maximize energy absorption. A new short-term reactive loading control technique is proposed that maximizes power absorption. The control is realized through tuning the effective stiffness of the vibrating system; thus, adjusting its natural frequency to meet the incident waves energy frequency achieving near-to-resonance operation and maximum power absorption. This stiffness is adjusted using an external stiffness, whose value is varied by a continuously variable transmission (CVT) mechanism connected to the buoy. The system equations were derived then solved analytically to calculate the controller bandwidth. Experiments demonstrated promising results for near-resonance tuning at different input frequencies. Results show that an optimized damping value exists at which power absorption can be significantly increased. The WEC equipped with the proposed reactive controller can provide faster tuning actions than long-term techniques. It also works on longer time intervals than phase-control methods; hence, reducing the continuous demands from the PTO system.

Novel adaptive tuned viscous inertance damper (ATVID) with adjustable inertance and damping for structural vibration control

In this study, we present an approach to alter the inertance of inerter-based devices, depending on the variation of the frequency of the external excitation. In this regard, we propose a newly developed variable inerter which is able to change the inertance using a versatile type of continuously variable transmission (CVT) mounted on a ball-screw inerter, it is called adaptive tuned viscous inertance damper (ATVID). The proposed device is capable of generating a variable inertance and viscous damping simultaneously contributed to provide seamless variability in its frequency. To evaluate the device performance, damping properties of the ATVID-controlled is compared with passive controlled and uncontrolled single-degree-of-freedom structures exposed to the harmonic ground excitation with variable frequency. Results show an excellent level of vibration reduction in structure using ATVID in a large width of the frequency band of the excitation.

Technical feasibility of a pneumatically driven vehicle

In this work, the technical feasibility of an all-air vehicle is investigated. A test rig has been built for this purpose in order to assess the proposed system experimentally. The operating pressures selected are deliberately low to mitigate the heat generated/dissipated during charging and discharging of the air cylinders driving an air motor, respectively. The experimental setup consists of three cylinders charged up to 5 bar and operated via solenoid valves to control the discharge of the cylinders via a programmable logic controller. The operating modes vary according to the expected load demand on the vehicle during startup and also during cruise. The three cylinders are discharged in tandem if the demand calls for high power density, then they are operated sequentially to augment the operational range of the vehicle. A simple sprocket-chain mechanism is used for its simplicity in this proof-of-concept stage to better understand the parameters pertinent to vehicle operation, which will later be replaced by a continuously variable transmission (CVT) gear. The results show a great potential for such mode of transport, especially for vast locales, such as a hospital, golf course or a university campus, with top velocities estimated to be around 14 km/h velocities and driven sprocket powers of 0.7 hp. Other combinations of drive gear ratio and cylinder discharge sequences result in a wide range of output power and maximum speed possibilities.

Fuel enhancement of parallel hybrid electric two-wheeler motorcycle

In this paper, design and simulation of a parallel hybrid electric two-wheeler motorcycle (PHETM) by means of continuous variable transmission (CVT) is illustrated. For simulation, the parallel hybrid electric power train model type in MATLAB/ADVISOR is customized. The internal combustion engine (ICE) be supposed to drive at elevated efficiency areas, in order to attain enhanced fuel economy and a reduced amount of emission. Simultaneously, the ICE must not activate at values of low torque areas. For that reason, get better it whilst ICE is ON, a new energy control strategy is proposed. In the new strategy, the electrical machine absorbs the extra torque of the ICE. This article proposes a PHETM system to propel the vehicle efficiently with reduced amounts of emission on comparing witha conventional vehicle. This system includes two modes of operations for achieving the better results known as motoring mode and generating mode. The switching from one mode to other is based on the vehicle speed which is sensed in real time. A drive cycle is generated by running the vehicle in normal and slightly gradient condition and finally the results are compared.

Case Study on Different Go Kart Engine Transmission Systems

Go Kart, by definition is a simple 4-wheeler, single seater on track vehicle with no differential and suspension system. Fabrication of go-kart aid in learning about all the divisions involved in vehicle design like chassis, steering, transmission, brakes and so on. In any vehicle, engine determines the speed and power of a vehicle, as so in go karts. McCulloch MC-10 was the first go kart engine which is a manually transmitted two stroke engines adapted from chain saw, manufactured by McCulloch Company.At present they are many engines existing which are appropriate for go kart. This paper aims to study the velocity, acceleration, torque, sprocket ratio and slipping condition of three different types of engines (manual transmission engine, continuous variable transmission engine and industrial engine). Engines are opted as per standards issued by Society of Automobile Engineers (SAE), India and abroad. Analytical formulations are used to carry-out the performance comparison. This study helps design engineers or automobile enthusiasts in proper selection of engines based on their need and their application.

PENGARUH PUTARAN TERHADAP KETAHANAN AUS PADA ROUND ROLLER DAN SLIDING ROLLER CONTINUOUSLY VARIABLE TRANSMISSION ESP 150 CC

Primary Shave Weight or often called roller is one component of the Continuously Variable Transmission system on the ESP 150 CC automatic motor which is often damaged, both wear and crack or break. Wear and tear is a phenomenon of loss of material from its surface to another or the movement of material on a surface or surface displacement with the passage of time over time this wear will cause damage to the roller rubbing against each other. To understand the life of roller components, it needs to be studied further. In the field of tribiology studies of the phenomenon of friction, wear on two objects that are in contact. This affects the life of a component, especially those that move in fast conditions with the level of loading, the process of wear due to contact becomes three parts, which include material, environment, operating conditions and geometry of the surface of the wear object. To quickly determine the condition of wear, a tribometer pin on disk test equipment is needed, this tool is used to test round roller components and Continuously Variable Transmission sliding roller ESP 150 CC, where the material is PTFE. The design of the surface contact mechanism in the radial direction so that the disk can rotate and this test equipment is given a speed of 1000, 2000, 3000 Rpm with of loading of 3 kg. Tests are carried out experimentally to determine the occurrence of wear, from the initial conditions to continuous conditions. The results show that the tribometer pin on disk test equipment is feasible to use to determine the damage parameters that occur. By looking at the weight of the roller that is reduced due to friction

Blagonravov Continuously Variable Transmission: computational model of load distribution over elements of control system

The paper presents a kinematic scheme of a differential planetary control gear designed to change the vibration amplitude of the intermediate links of the Blagonravov mechanical continuously variable transmission on the move and under load. A computational model of load distribution over the elements of the planetary gear is developed. The influence of the internal gear ratio and vibration amplitude on the load distribution is estimated. The established dependencies are recommended to be applied when choosing the drive motor power of the transmission control system.