Continuously Variable Transmission Research Articles

Decoupling Analysis of Brushless Dual-Mechanical-Port Dual- Electrical-Port Machines

The brushless dual-mechanical-port dual-electrical-port (BLDD) machine has emerged as a promising alternative to the traditional mechanical continuously variable transmission (CVT), due to its gearless and brushless design. In BLDD machines, two sets of windings are placed in the same stator, and care must be taken to avoid strong coupling that may deteriorate the machine performance and reliability. This paper categorizes the topologies of existing BLDD machines into five types and presents a systematic decoupling analysis from the perspective of field-modulation theory. Using the presented method, the conditions to achieve decoupled designs are concluded and the decoupling characteristics of each type of BLDD machine are identified. Besides, a simple indicator is developed to fast identify the coupling type, i.e., decoupled, low or high coupling design, of BLDD machines, enabling an efficient selection of slot-pole combinations. With the aid of finite-element analysis (FEA), the coupling degree of BLDD machines with various slot-pole combinations has been analyzed for verification. Other performances, such as torque density and PM utilization, are also compared among the five types of BLDD machines to provide a more comprehensive view of their characteristics. Finally, a prototype of a BLDD machine is manufactured and tested to validate the analysis.

Design, Analysis and Manufacturing of Continously Variable Transmission of all Terrain Vehicle

This project focuses on the integration of Continuously Variable Transmission (CVT) technology into All-Terrain Vehicles (ATVs) to enhance their adaptability and performance. The aim is to design, analyse, and manufacture a specialized CVT system tailored to the unique requirements of ATVs. Recognizing the challenges faced by conventional transmission systems in off-road environments, the project seeks to optimize power delivery, improve acceleration, and enhance fuel efficiency through the implementation of a well-designed CVT. The project begins with a comprehensive literature review, providing insights into the existing knowledge on CVT technology and its relevance to off-road vehicles. The conceptual design phase involves generating innovative design concepts, aligning with the specific needs of ATV applications. Engineering analysis, a critical aspect of the project, utilizes simulation tools and mathematical modelling to ensure the reliability, durability, and efficiency of the proposed CVT system under diverse operating conditions.

A Duster Plug-in Hybrid Electric Vehicle with Wireless Charging System

The paper presents the GASTER Electricway 4WD concept, Plug-in Hybrid Electric Vehicle (PHEV) type, in development within the Automotive Engineering Research Centre of the University of Pitesti, aiming to create a green and versatile version of Romanian Dacia Duster. The car has been built by implementing a hybrid propulsion system with electrified rear axle. This hybrid system is PHEV, parallel type with two shafts, organized in a motorized solution E4WD (Electricway 4WD). It is composed of a thermal power train with a 1.6 litre engine fuelled with Compressed Natural Gas (CNG) and a CVT (Continuously Variable Transmission), placed in the front of the vehicle. The electric powertrain, located at the rear side of the vehicle includes an electric motor coupled with a mechanical transmission. The traction battery is Lithium-ion NMC type. The charging of the traction battery can be performed with the on board charger of by cable from a Wallbox or public station, in the Standard version, and Plug-in bidirectional or Wireless from renewable sources in the Premium version.

Pengaruh Massa Weight Roller terhadap Keausan Material dan Akselerasi Motor N-Max

The Nmax motorbike roller basically consists of 6 units which function to maintain and regulate motor acceleration found in the Roller Housing in the Continuously Variable Transmission (CVT) section which allows friction and wear to occur on the roller material. Acceleration is the level of acceleration that occurs in an object at a certain time, while material wear is the mechanical property of an object to accept loads, power and energy without causing damage. This research was carried out using a Tribometer test tool and logger pro analysis software. The results obtained show that material wear increases with increasing RPM. At 500 rpm, standard roller wear ranges from 0.107% to 0.346%, while at 1400 rpm, wear increases to range from 0.323% to 0.938%. The acceleration test results show that the standard roller with a mass of 13 grams has the lowest acceleration performance, with the lowest value occurring in test II at 1.26 m/s². Meanwhile, the 9 gram roller has the highest average acceleration of 4.82 m/s².

Common transmission theory and wide application

Gear and belts/chains are the most common solution for modern mechanical devices. The allowable stress and gear ratio are two of the main factors that decide the performance of the ear section for transmission. The allowable stress can be calculated by bending stress and contact stress from design criteria. The performance of the belt solution is decided by the belt/chain material, center distance and the belt length. The allowable strength of the belt/chain solution is strongly related to the materials selected. With the current study of belts and gears, the related factors could be calculated to design the optimum shape and material. Dual clutch transmission (DCT) and continuously variable transmission (CVT) are two widely applied transmissions with gear and belt/chain solutions that are introduced in the research. The advantages of DCT could be the reliability and high transmission efficiency of the gear solution and the space and energy efficiency of belt/chain structure advantages of the CVT. Both DCT and CVT could be applied in different conditions to maximize the specific performance.

A Continuously Variable Transmission-Based Variable Stiffness Actuator for pHRI: Design Optimization and Performance Verification

Abstract Physical human–robot interfaces (pHRIs) enabled the robots to work alongside the human workers complying with the regulations set for physical human–robot interaction systems. A variety of actuation systems named variable stiffness/impedance actuators (VSAs) are configured to be used in these systems’ design. Recently, we introduced a new continuously variable transmission (CVT) mechanism as an alternative solution in configuring VSAs for pHRI. The optimization of this CVT has significant importance to enhance its application area and to detect the limitations of the system. Thus, in this paper, we present a design optimization approach (an adjustment strategy) for this system based on the design goals, desired force, and minimization of the size of the system. To implement such design goals, the static force analysis of the CVT is performed and validated. Furthermore, the fabrication of the optimized prototype is presented, and the experimental verification is performed considering the requirements of VSAs: independent position and stiffness variation, and shock absorbing. Finally, the system is calibrated to display 6 N continuous output force throughout its transmission variation range.

APPLYING REGULAR RELIEF ONTO CONICAL SURFACES OF CONTINUOUSLY VARIABLE TRANSMISSION TO ENHANCE ITS WEAR RESISTANCE

While investigating the variator transmission of vehicles, the relationship between the technological and service parameters of the working surfaces of conical disks treated by technological methods was established. The service properties are proposed to be enhanced by Regular MicroReliefs (RMRs) created on such surfaces. The optimal technological processing conditions were found, which allow retaining the greatest amount of lubricant. The causes of surface defects, formed on the working surfaces of conical disks of the Continuously Variable Transmission (CVT), are systematized and classified. The wear resistance of such surfaces is proposed to be enhanced by technological methods, in particular, by forming partially RMRs on them. Their application facilitates relaxation processes on the material near to the surface, reduces shear stresses and strains, thus preventing the formation of burrs and extending the life of the conical disks of the CVT. A novel approach for obtaining the toolpaths of the deforming element, based on the so-called “Commis–Voyageur problem” algorithms, is employed in order to research the possibilities for involving that methods in toolpath generation. Dependences between the partial RMR’s formation conditions (deforming forces and feedrate) and microgeometric quality parameters are established. The latter include surface roughness, with a partially RMR applied onto the face surfaces of the test specimen (rotary body). It is found that these microreliefs enhance the ability of oil retaining in plastically deformed traces, formed over the operational surfaces, in comparison with those, that are processed by traditional cutting methods, as turning for example.

Battery Electric Vehicles: How Many Gears? A Technical–Economic Analysis

The large majority of electric cars have a single-speed gearbox, because electrified powertrains provide maximal power across a wide operating range, and single-speed simplifies construction and reduces capital costs. Nevertheless, multi-speed transmissions have also been developed for electric cars, and some of them have recently appeared as commercial products. This paper aims to compare, through some practical examples, solutions with single-speed and dual-speed transmissions. In particular, given the very smooth driving of electric cars, for dual-speed solutions, a dual-clutch gearbox was considered. Finally, a continuously variable transmission (CVT) was also used. Different solutions were analyzed from a technical–economic point of view, based on a simulation of the vehicle under standardized driving cycles, thus evaluating the capital and running electricity costs. The obtained results show that the comparison between the two solutions is very open, and in the majority of cases, the advantages in terms of efficiency overcome the disadvantages due to the additional capital costs. For a rather low battery cost of 150 €/kWh, the total cost reduction moves from about 100–150 € up to 1500–2000 €, depending on the electricity cost, along the whole vehicle lifespan.

AGRICULTURAL MECHANIZATION EVOLUTION: the journey of mechanizing harvesters and tractors - a study focusing on CASE IH® machinery

The research presents an analysis of the evolution of agricultural mechanization, focusing on the tractors and harvesters of the brand CASE IH®. CASE IH® has a deep-rooted history in American agriculture, resulting from the merger of several pioneering companies in the early 20th century. Since then, it has played a crucial role in the global evolution of agriculture, offering high-quality equipment that has transformed agricultural work methods. The present study aims to: present the evolution of machinery in agriculture, emphasizing innovation and technology over time, and demonstrate the progression of CASE IH® brand tractors and harvesters. This research has a basic nature and adopts a qualitative approach with descriptive and exploratory objectives, using the method of narrative literature review through bibliographic research. The evolution of agricultural mechanization has had a significant impact on the productivity and efficiency of the agricultural sector. CASE IH® demonstrates its commitment to efficiency and sustainability by introducing technologies such as the Advanced Farming System (AFS) and the Continuously Variable Transmission. This research underscores the importance of understanding this evolution to envision the future potential of agriculture and the opportunities that may arise.

Research on Designing the Continuously Variable Transmission Test Bench

The continuously variable transmission (CVT) is designed to enhance the performance of the powertrain system. It helps the vehicle have better acceleration as well as improves the fuel economy. Fuel consumption in a car is directly linked to transmission efficiency, primarily influenced by the vehicle's drivetrain system. Factors affecting the transmission efficiency of transmission including belt structure, hydraulic pressure, and control technique are factors that need to be studied and improved. This study was carried out to calculate and design the mechanical, hydraulic, and electrical control systems of a CVT test bench. With the initially designed test bench simulated, it is possible to evaluate the characteristic quantities controlling the transmission ratio of the gearbox such as the pressure acting on the pulleys, the force acting on the belt, the torque at axes corresponding to different load modes vary from 2kW to 6 kW. The results of this study will be the basis for manufacturing an experimental system for in-depth studies and evaluation of the CVT such as belt slip, as well as the factors affecting transmission efficiency of CVT.

The Effectiveness of Using Continuous Variable Transmission (CVT) in 2WD Buggy Vehicles

Continuous Variable Transmission (CVT) is a transmission system that does not have gears like in manual transmission cars or conventional automatic transmission cars. CVT has the advantage of being able to maintain the proper rotational speed at any time in terms of engine efficiency by changing the speed ratio flexibly and continuously. A continuously variable transmission (CVT) is a transmission that can change steplessly through an infinite effective gear ratio between maximum and minimum. This is in contrast to other mechanical transmissions which only allow a few different gear ratios to choose. The flexibility of the CVT allows the drive shaft to maintain a constant angular speed over the output speed range. Torque is transmitted from the drive to the pulley which is driven by friction acting between the belt and pulley surfaces. Tests were carried out using a dynotest to obtain wheel rotation data and the resulting torque. The loading is given from 3 kg, 5 kg, 7 kg and 8 kg, the engine rpm used is 5500 rpm, 6000 rpm, 6500 rpm, 7000 rpm and 8000 rpm. Rear wheel rotation is inversely proportional to the load, the greater the load the rotation will decrease. Load is directly proportional to torque, the greater the load given the torque will increase. The CVT system is still effective for use as a power successor. The power that can be transmitted is still greater than 50%, namely 68%.

Investigation and Optimization of Energy Consumption for Hybrid Hydraulic Excavator with an Innovative Powertrain

This paper presents an innovative powertrain design and an energy regeneration system for hybrid hydraulic excavators to reduce energy consumption and emissions. The proposed system is designed to maximize engine efficiency and make full use of the energy gained from boom and arm retraction. The powertrain features an innovative design that incorporates a continuously variable transmission (CVT), which drives the main pump. It enables precise control of both the engine’s speed and torque, ensuring that the engine operates within the high-efficiency range. The energy regeneration system is applied to regenerate the potential energy of the boom and arm, which can be used to either charge the battery or directly supply power to the main pump. Moreover, an energy management strategy based on an equivalent consumption minimization strategy is used to distribute the power while offering maximum engine efficiency. When compared with the existing hybrid system and conventional system, the simulation results indicated that the proposed approach achieves energy-saving efficiencies of 16.9% and 77.1%, respectively, at high velocities and 22.25% and 53.5%, respectively, at medium velocities. This research signifies a promising advancement for sustainable and efficient hydraulic excavator operations.

Rotational Speed Optimization of Coaxial Compound Helicopter and Turboshaft Engine System

In order to enhance the overall performance and operational efficiency of the integrated coaxial compound helicopter and turboshaft engine system, a preliminary study on the optimal rotational speeds was implemented based on multidisciplinary integration. First, the flight mechanics model of coaxial compound helicopter and the aerothermodynamic model of turboshaft engine were developed. Then, the minimum fuel flow of the turboshaft engine was selected as the optimization objective, and an integrated optimization method of optimal rotational speeds based on the golden section method was proposed according to fixed ratio transmission (FRT) and continuously variable transmission (CVT). Finally, the effect of the optimal rotational speeds on the overall performance of the integrated system was investigated, and the variation laws of the optimal rotational speeds under different operating modes were revealed. The results indicated that the optimal rotational speeds can decrease engine fuel flow by a maximum of more than 10%, which is conducive to promoting operational economy and overall performance. Moreover, the flight conditions, helicopter weight, and engine degradation significantly affect the optimal main rotor speed.

Design principles and traction performance of a novel zero-spin rolling conical traction continuously variable transmission

In the existing traction continuously variable transmission (CVT), half toroidal CVT (HT-CVT) is considered to have a better traction performance. However, the HT-CVT has the spin losses due to its structural limitations, which significantly influences the traction efficiency. In this paper, the kinematic qualities and contact models of a novel zero-spin rolling conical CVT (RC-CVT) are studied, and then the rollers and conical disks are compactly designed through the proposed design principles. Subsequently, the transmission efficiency is investigated by using a detailed numerical model and compared with HT-CVT. Based on these computational models and parameters, the practical spin ratio, spin momentum and traction efficiency of RC-CVT are calculated and compared with HT-CVT. The results show that the practical spin ratio and spin momentum of RC-CVT are much smaller than that of HT-CVT, and the efficiency on fixed transmission ratio is consequently higher than that of HT-CVT.

On the design and power output response of hydraulic wind turbines

Standard horizontal axis wind turbines typically use gearboxes for large-scale applications and direct coupling for small-scale designs to connect the rotor to the generator. However, gearboxes pose challenges due to their weight, cost, and exposure to dynamic loads and vibrations within the nacelle. A promising alternative is replacing mechanical transmission with a hydrostatic counterpart, offering advantages such as reduced nacelle mass, generator placement at the tower base, and elimination of the gearbox. It can potentially lead to cost savings of up to 20% in the levelized cost of electricity for offshore wind turbines. This study compares regulated hydrostatic transmission with unregulated transmission and damping components under different wind conditions, including atmospheric boundary layer and low-level jet inputs. Dynamic simulations of a horizontal axis wind turbine incorporating a hydrostatic transmission are conducted to evaluate its response to wind fluctuations caused by prevailing wind velocity profiles, atmospheric boundary layer, and low-level jet velocity profiles. Addressing torque fluctuations and power impact on power quality and mechanical components is crucial in wind turbine operation. The proposed hydrostatic transmission includes primary and secondary proportional controllers for adaptability to varying wind speeds, along with integrated accumulators in the high and low-pressure lines. The main findings indicate that the regulated hydrostatic transmission achieves an efficiency range of 69%–75% across various wind velocity profiles, surpassing the unregulated counterpart. It reduces torque fluctuation amplitude by 35% and improves efficiency by nearly 20% compared to the basic transmission. Torque and power fluctuations are also reduced by 35% and 40%. These improvements are attributed to the damping capabilities of the hydrostatic transmission and the actions of the proportional controller. Implementing the regulated hydrostatic transmission offers several technical and economic advantages, including relocating the generator to ground level and achieving continuous hydraulic variable transmissions without the need for a gearbox. The methodology is applicable to a range of wind turbine sizes.

ANALISA DISTRIBUSI KEKERASAN KOMPONEN MOVABLE PULLEY DRIVEN (MPDN) PADA TRANSMISI KENDARAAN

Transmission on the vehicle is very important component to ensure maximum power transfer from the engine to the wheels. The speed of four-wheeled vehicles is influenced by the transmission system used. Pulley is the component of continuous variable transmission (CVT) which is currently widely used in the automotive industry. The CVT transmission is type of automatic transmission with gearshift process that does not use gears, but uses pulley. The pulley is made of stainless steel. For CVT transmission there are two pulleys, both of which are called driven pulleys. The CVT transmission shift operation is controlled electronically from the computer to drive the two pulleys. These two pulleys can move to the right or to the left, respectively, so that the width of the two pulleys can change to narrow or widen. The drive pulley moves away so the belt will move inward and the same time the driven pulley will narrow so the belt will move further out. The pulley diameter becomes the gear ratio in a CVT transmission. In the CVT transmission process there will be friction between the two surfaces of the pulley and the belt, therefore it is necessary to measure the hardness of the material from the pulley to ensure the vehicle's transmission capability. In this study, the hardness of the pulley material was measured using a Vickers machine according to the ASTM 6507 standard with a given load of 0.3 kg. The measurement results obtained an average value of hardness Vickers (HV) for the pulley material of 473.

Application and Efficiency of a Series-Hybrid Drive for Agricultural Use Based on a Modified Version of the World Harmonized Transient Cycle

Off-road vehicles and transportation are vital for agricultural economics, yet the transition to green energies is challenging. To make this transition easier, a tool that enables the testing of heavy-duty off-road vehicles in various scenarios was created. Based on the methods of the World Harmonized Transient Cycle (WHTC), a new Hybrid Operational Cycle (HOC) that reflects the features of agricultural work was created and applied in a graphical model simulation. This was a newly developed methodology. The cycle and the model were based on gathered research data. A numerical model of a medium-power tractor with an internal combustion engine and a series-hybrid setup was created, and simulations were performed in Matlab and AVL Cruise. Both diesel and hybrid vehicles were compared in terms of their power production, fuel consumption, and efficiency in fieldwork and transportation scenarios. The results showed that a series-hybrid transmission can achieve an efficiency similar to that of a tractor with a continuously variable transmission (CVT), but because it uses an electric powertrain, it still provides the opportunity to exploit energy regeneration during transportation and under low-load conditions. The designed model may also be used to develop control algorithms for hybrid drives and improve their efficiency.

The Effect of Continuous Variable Transmission Spring Variation on 110 CC 4 Stroke Fuel Motor

Dalam penelitian ini yang dilakukan terhadap sepeda motor khususnya sepeda motor bertransmisi otomatis (matic). Berdasarkan hasil observasi yang dilakukan kepada pengguna sepeda motor bertransmisi otomatis (matic) terdapat keluhan yang dirasakan pengguna, hal yang sering dikeluhkan yaitu performa motor yang kurang responsife. Ada beberapa cara untuk meningkatkan performa sepeda motor maic salah satunya mengganti spring pada continuous variable transmission (CVT). Pengujian dilakukan pada sepeda motor Honda Beat FI 110 cc tahun 2013. Tujuan pengujian untuk mengetahui seberapa besar pengaruh spring cvt terhadap daya, torsi, dan konsumsi bahan bakar yang dihasilkan pada sepeda motor dengan variasi spring racing 6100 – 6300 rpm. Metode yang digunakan dalam penelitian ini adalah metode penelitian eksperimen, yaitu sebuah penelitian yang berusaha mencari pengaruh variabel tertentu terhadap variable lain dalam kondisi yang terkontrol. Dari hasil penelitian didapatkan hasil daya terbesar pada spring racing sebesar 7,1 hp pada putaran meisn 6300 rpm, sedangkan torsi terbesar yang dihasilkan terdapat pada putaran mesin 6300 rpm sebesar 8,1 N.m dengan penggunaan spring racing. Pada kosumsi bahan bakar minimal yang dihasilkan sebesar 0,233 Kg/jam.hp pada putaran mesin 6100 rpm dengan menggunakan spring racing.

Design of Linear Functional Noncircular Gear with High Contact Ratio Used in Continuously Variable Transmission

Continuously variable transmission (CVT) of noncircular gear has the technical advantages of large bearing capacity and high transmission efficiency. The key technology of CVT with noncircular gear has been broken through some countries, and is in the stage of deep application research. Although the characteristics and design methods of noncircular gear pairs have been continuously studied in China, the noncircular gear CVT is still in the preliminary exploration and research stage. The linear functional noncircular gear pair, whose transmission ratio is a linear function in the working section, to realize continuously variable transmission was the research object in this paper. According to the required transmission ratio in the working section, the transmission ratio function in the non-working section was constructed by using a polynomial. And then the influence of pitch curve parameters in the working section on which in the non-working section was also analyzed to obtain the pitch curve suitable for transmission of this gear pair. In addition, for improving the stability and bearing capacity of gear transmission, the noncircular gear pair transmission with high contact ratio was designed. Furthermore, the accurate value of the contact tooth length was calculated based on the gear principle and the characteristics of the involute tooth profile, from this the contact tooth length error was calculated by comparing the accurate value with its actual value obtained by the rolling experiment. Finally, an indirect method to verify the contact ratio by detecting the contact length error of the tooth profile was proposed.

THE EFFECT OF V-BELT SIZE AND GROOVE ANGLE VARIATION ON THE SURFACE OF THE CVT CLUTCH DISK ON THE POWER AND TORQUE TRANSMISSION OF 125CC MOTORCYCLE

Continuously Variable Transmission (CVT) is an automatic transmission system with gear ratio shifts following engine speed controlled by the primary and secondary pulleys, as well as the V-belt that connects the two pulleys. The disadvantage of the CVT transmission system is that it often loses grip on the CVT clutch lining and the V-belt at low and high rotation so that research needs to be done so that the power from the engine to the wheels can be maximized. This study used an experimental method by changing the variation in the size of the V-belt and the groove angle on the clutch pads to find the best size for a 125 CC motorbike. The results showed that to get maximum results it is recommended to use a V-belt 803 x 19.0 mm with a CVT lining of 30° producing the highest power and a V-belt 840 x 21.8 mm with a CVT lining of 90° producing the highest torque