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Viewing 1 to 30 of 2848
2016-11-08
Technical Paper
2016-32-0036
Takamori Shirasuna, Ryoh Hatakeyama, Yukio Sakai
In recent years, the need is growing for a fuel efficiency enhancement of motorcycles equipped with Continuously Variable Transmissions (CVT), of which the vehicle sales volume is rapidly increasing in developing countries. To develop a vehicle with excellent fuel efficiency, a precise estimation of fuel economy is required at the beginning stage of a vehicle development. One of the indices that are used for evaluation of fuel economy of a vehicle is fuel economy to a predetermined test mode of driving (mode fuel consumption). One of the parameters that plays an important role for the mode fuel consumption calculations is pulley ratio of CVT. In rubber belt CVTs for motorcycles, their pulley ratio varies at every moment depending on the balance between the traveling resistance and thrust force applied to the sidewall of the belt. The state of this pulley ratio variation differs among vehicles and/or among CVT specifications.
2016-10-17
Technical Paper
2016-01-2311
Arun Prasath G, Saravanan Duraiarasan, Govindarajan R
Indian two wheeler market is one of the largest and highly competitive in the world. Indian scooter segment grows at a pace of around 30% YOY. The stiff competition among OEM’s to increase the market share with fuel efficient and high performance products pushes development and calibration engineers to burn the midnight oil to concoct innovative methods to design technology boosted product. Customer expectations are always high in terms of fuel economy, drivability and NVH. Due to higher level of complexity involved in CVT (Continuously Varying Transmission) engine, it is daunting task to optimize for achieving best of NVH characteristics along with Fuel Economy, drivability and reduced exhaust emission. This paper describes the experiment conducted during the development of 110cc CVT four stroke scooter engine. The development and calibration of this scooter was mainly based on real world usage pattern (RWUP).
2016-10-17
Technical Paper
2016-01-2206
Darryl Williams, Jeffrey Guevremont, John Perry
Good shift quality in automatic transmissions is important for fuel efficiency, driver comfort, and performance. Maintaining this performance over the life of the vehicle is also important. Typical lubricant development focuses on reducing viscosity and friction in order to reduce parasitic losses. In an automatic transmission, other factors are also important for good performance, primarily due to the shifting and torque converter clutches. A high level of friction is desirable for torque capacity and a steady decrease in friction as sliding speed (rpm) decreases is necessary for both good shift feel and good friction system durability over the lifetime of the vehicle. Friction system changes over time that result in a lowering of the friction level at high sliding speed compromise the performance of both types of clutches.
2016-10-17
Technical Paper
2016-01-2356
Shaopeng Tian, Geng Li, tongliang que
A set of test bench of manual transmission efficiency is designed,which is used to research the transmission efficiency of manual transmission in different working conditions. This paper introduces the basic structure and control principle of the test bench and analyzes the impact of the gearbox lubricating oil temperature and load on the transmission efficiency according to the measured data. The bench adopts two AC asynchronous motor to simulate the driving and load of the vehicle,the upper computer of test bench uses C++ to write the control program,the lower computer adopts PLC to control S120 Control cabinet which is used to adjust the speed of driving motor and the torque of load motor,the upper computer and the lower computer communicate through the OPC protocol.The bench collects experimental data signal and outputs the corresponding control signal by NI PCI-6221 data acquisition card.
2016-10-17
Technical Paper
2016-01-2344
Darryl Williams, Jeffrey Guevremont, John Perry
Good shift quality in automatic transmissions is important for fuel efficiency, driver comfort, and performance. Maintaining this performance over the life of the vehicle is also important. Typical lubricant development focuses on reducing viscosity and friction in order to reduce parasitic losses. In an automatic transmission, other factors are also important for good performance, primarily due to the shifting and torque converter clutches. A high level of friction is desirable for torque capacity, and a steady decrease in friction as sliding speed (rpm) decreases is necessary for both good shift feel and good friction system durability over the lifetime of the vehicle. Friction material surface characteristics have a dramatic impact on changes in friction level with sliding speed (the mu-v curve) and the performance of the friction system is heavily impacted by changes in these characteristics.
2016-10-17
Technical Paper
2016-01-2343
Mark Devlin, Darryl Williams, Michael Glasgow, Karen Hux, Aaron Whitworth, Timothy Cameron
Improving vehicle fuel efficiency is a key market driver in the automotive industry. Typically lubricant chemists focus on reducing viscosity and friction to reduce parasitic energy losses in order to improve automotive fuel efficiency. However, in a transmission other factors may be more important. If an engine can operate at high torque levels the conversion of chemical energy in the fuel to mechanical energy is dramatically increased. However high torque levels in transmissions may cause NVH to occur. The proper combination of friction material and fluid can be used to address this issue. Friction in clutches is controlled by asperity friction and hydrodynamic friction. Asperity friction can be controlled with friction modifiers in the ATF. Hydrodynamic friction control is more complex because it involves the flow characteristics of friction materials and complex viscosity properties of the fluid.
2016-10-17
Technical Paper
2016-01-2205
Chris McFadden PhD, Kevin Hughes PhD, Lydia Raser PhD, Timothy Newcomb
Hybrid drivetrain hardware combines an electric motor and a transmission, gear box, or hydraulic unit. With many hybrid electric vehicle (HEV) hardware designs the transmission fluid is in contact with the electric motor, and so some OEMs and tier suppliers have concerns about the electrical properties of automatic transmission fluids (ATFs). Lubrizol has conducted a fundamental research project to better understand the electrical conductivity of ATFs. In this paper we will present conductivity data as a function of temperature for a range of commercially available lubricants, including engine oils and gear oils, in addition to ATFs. All fluids, regardless of type, had conductivities in the range of 1E-8 to 1E-10 S/cm at 100oC and as such are good insulators with the ability to dissipate static charge. Next we will deconstruct one ATF to show the relative impact of the various classes of lubricant additives.
2016-10-17
Technical Paper
2016-01-2357
Onkar P. Gurav, Santosh Deshmane
Globalization has intensively driven focus of car manufacturers on comfort and ergonomics. Luxuries are becoming essential features of product mix. Customer’s expectations and desires are changing because of cut throat competition and increasing variety of options. In order to sustain in marketplace OEM has to be competitive while providing features and options with appropriate quality. Vigorously changing dimensions and definitions of comfort level, luxury and aesthetics driven the intense focus of OEM’s on customer touch points, customer touch points are those components of vehicle which customer accesses while driving the vehicle and they play vital role in generating drive feel of vehicle. Customers drive feel about the vehicle is most complex and critical factor and is of subjective nature. Now days drive feel is an important aspect of product differentiation. Gear shift feel is very crucial touch point in overall drive feel of vehicle.
2016-10-17
Technical Paper
2016-01-2207
Elizabeth Schiferl, Timothy N. Hunt, Robert Slocum
With government mandates, OEMs are increasingly focusing on fuel economy and finding efficiency gains throughout the vehicle. Lubricant companies have been asked to design fluids (engine oil, transmission fluid, and gear oil) that can deliver efficiency improvements. Demonstrating real gains becomes quite complex given the intricacies of these systems, and methods range from bench top screen tests to component test stands to full vehicle testing. This paper addresses the variation that can occur when testing automatic transmission fluid efficiency within a full vehicle test. Lubrizol has tested at several independent laboratories and found that ignoring the magnitude of the impact of variation in average operating conditions between tests can mislead as to which fluid is delivering greater efficiency benefit.
2016-10-17
Technical Paper
2016-01-2353
Kazunori Harima, Shinji Tsuchiya, Takuro morino, Yuji Nagasawa
CVT belts are constructed with multiple elements and layered rings, and friction loss occurs between each parts. Due to belt geometry, a large belt friction loss occurs between the elements and the inner most ring. Therefore, to improve efficiency, it is effective to decrease the slip between the elements and the inner most ring. So, the torque transmitted is influenced by the slip between the elements and the inner most ring. When the slip is decreased, it is thought that the amount of torque transmitted by the ring change. For efficiency improvement, it is necessary to analyze the change of the torque transmitted by the ring due to the decrease of slip between the elements and the inner most ring, but to verify of the internal thrust force in the real load state is difficult because it is a phenomenon inside the belt.
2016-09-27
Technical Paper
2016-01-8019
Marius-Dorin Surcel, Adime Kofi Bonsi
The main objective of this project was to compare the fuel consumption and dynamic performances of direct-drive and overdrive transmission tractors. Fuel consumption was evaluated at constant high speed and on various road profiles, while the dynamic performances were assessed on various road profiles only. The SAE Fuel Consumption Test Procedures Type II (J1321) was used for constant high speed fuel consumption track test evaluations. The tests were conducted with loaded two-axle van semi-trailers. The direct-drive transmission tractors consumed less than the overdrive transmission tractor, even though they were roughly 450 kg and 750 kg heavier, respectively.
2016-09-27
Journal Article
2016-01-8099
Andrea Bassi, Massimo Milani, Luca Montorsi, Stefano Terzi
Abstract The paper investigates the oil flow through a multi plate clutch for a hydro-mechanical variable transmission under actual operating conditions. The analysis focuses on the numerical approach for the accurate prediction of the transient behavior of the lubrication in the gear region: the trade-off between prediction capabilities of the numerical model and computational effort is addressed. The numerical simulation includes the full 3D geometry of the clutch and the VOF multi-phase approach is used to calculate the oil distribution in the clutch region under different relative rotating velocities. Furthermore, the lubrication of the friction disks is calculated for different clutch actuation conditions, i.e. not-engaged and engaged positions. The influence of different geometrical features of the clutch lubricating circuit on the oil distribution is also determined.
2016-09-27
Technical Paper
2016-01-8067
Suresh Kumar Kandreegula, Kamal Rohilla, Gaurav Paliwal, Naveen Sukumar, Naveen Pratap Tripathi
Abstract Three on the tree, four on the floor. The gear change mechanism is a component that is too often taken for granted but it is one of the more important features of the vehicle. It must be quick and smooth in action, efficient and totally reliable. Modern driving conditions demand that the driver makes frequent gear changes and a mechanism that is temperamental or inaccurate can be both frustrating and dangerous as well as physically tiring. The gear changing mechanism starts, quite obviously, with the gear lever. Most stem from the fact that a gear lever must move in two planes, forward and back and then from side to side to move across the gear "gate". A good many drivers think of gear changing as one simple action. This is more a tribute to the design of gear changing mechanisms than a reality. There are multiple gear selector mechanisms that are available for use in commercial vehicle industry.
2016-09-27
Technical Paper
2016-01-8080
Yanwu Ge, Ying Huang
Abstract The ever-growing number of interacting electronic vehicle control systems requires new control algorithms to manage the increasing system complexity. As a result, torque-based control architecture has been popular for its easy extension as the torque demand variable is the only interface between the engine control algorithms and other vehicle control systems. Under the torque-based control architecture, the engine and AT coordinated control for upshift process is investigated. Based on the dynamics analysis, quantitative relationship between the turbine torque of HTC and output shaft torque of AT has been obtained. Then the coordinated control strategy has been developed to smooth the torque trajectory of AT output shaft. The designed control strategy is tested on a powertrain simulation model in MATLAB/Simulink and a test bench. Through simulation, the shift time range in which the engine coordinated control strategy is effective is acquired.
2016-09-27
Technical Paper
2016-01-8069
MahendraMohan Rajagopal, Suresh Kumar N, Nageshwara Rao P
Abstract In any drive system, tooth mesh misalignment originates primarily from its torque transmitting components such as spline connections, gears, shafts, bearings and housing. The major influencing factors for tooth mesh misalignments are clearance between components, deflection, stiffness, thermal expansion, manufacturing limitations and assembly limitations. Tooth mesh misalignments in heavy duty off-highway applications like tractor, propagates drastically while handling severe loads and tends to shift the load distribution in a gear pair to an un-biased manner along the facewidth, resulting in high contact stresses and poor transmission performance. Misalignments definitely add few more decibels to the driveline system which will be an annoyance to the user. Moreover, mesh misalignments in any drive system cannot be eliminated and hence different approaches and methods were followed to compensate the misalignment.
2016-06-17
Journal Article
2016-01-9141
Vinod Saini, Sanchit Singh, Shivaram NV, Himanshu Jain
Abstract In this paper, an optimization method is proposed to improve the efficiency of a transmission equipped electric vehicle (EV) by optimizing gear shift strategy. The idea behind using a transmission for EV is to downsize the motor size and decrease overall energy consumption. The efficiency of an electric motor varies with its operating region (speed/torque) and this plays a crucial role in deciding overall energy consumption of EVs. A lot of work has been done to optimize gear shift strategy of internal combustion engines (ICE) based automatic transmission (AT), and automatic-manual transmissions (AMT), but for EVs this is still a new area. In case of EVs, we have an advantage of regeneration which makes it different from the ICE based vehicles. In order to maximize the efficiency, a heuristic search based algorithm - Genetic Algorithm (GA) is used.
2016-06-15
Journal Article
2016-01-1852
Ehsan Fatourehchi, Vishak Elisaus, Mahdi Mohammadpour, Stephanos Theodossiades, Homer Rahnejat
Abstract Efficiency and durability are key areas of research and development in modern racing drivetrains. Stringent regulations necessitate the need for components capable of operating under highly loaded conditions whilst being efficient and reliable. Downsizing, increasing the power-to-weight ratio and modification of gear teeth geometry to reduce friction are some of the actions undertaken to achieve these objectives. These approaches can however result in reduced structural integrity and component durability. Achieving a balance between system reliability and optimal efficiency requires detailed integrated multidisciplinary analyses, with the consideration of system dynamics, contact mechanics/tribology and stress analysis/structural integrity. This paper presents an analytical model to predict quasi-static contact power losses in lubricated spur gear sets operating under the Elastohydrodynamic regime of lubrication.
2016-05-01
Journal Article
2015-01-9144
Marc-Olivier Lacerte, Gabriel Pouliot, Jean-Sébastien Plante, Philippe Micheau
Electric Vehicles (EVs) with single-ratio gearbox provide high levels of smoothness, but using multi-speed gearbox can provide significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. In particular, Automated Manual Transmissions (AMTs) have characteristics of smooth shifts without torque interruption when coupled to a torque bypass clutch. However, conventional friction clutches are not best suited as torque bypass clutches because of their limited controllability and because large amount of heat must be dissipated to slow down the motor during gearshifts. This paper studies the feasibility of a seamless AMT architecture for EVs and Hybrid Electric Vehicles (HEVs) using an eddy current torque bypass clutch that is highly controllable, robust, low cost, and has no wearable parts.
2016-04-11
Journal Article
2016-01-9016
Mohammad Gerami Tehrani, Juuso Kelkka, Jussi Sopanen, Aki Mikkola, Kimmo Kerkkänen
Abstract The feasibility of improving the energy efficiency of Electric Vehicles (EV) by manipulating operation points by means of a variable transmission is investigated with an efficient mathematical model of power losses in all driveline components. Introduced model can be solved in real-time making it possible to embed it to a control scheme of EV. Empirical test results are employed to derive the efficiency of the power electronics and electric motor at operation points while the mechanical power losses are predicted by a comprehensive and generic formulation for efficiency analysis. The simulation model used comprises electrical component efficiency, drivetrain inertias, gearbox efficiency, regenerative braking, and gear ratio selection. Three different transmission types are studied in this work; a single reduction gear, a five-step gearbox and an Infinitely Variable Transmission.
2016-04-05
Technical Paper
2016-01-1061
Guiping Yue, Wenbo Niu, Jian Zhao, Dandan Kong, Yun Li, Hangsheng Hou
Abstract Gear whine noise impacts customer perception of vehicle interior quietness in general and sound quality in particular. It has been a frequently occurred annoying phenomenon during vehicle development and much discussed topic regarding transmission NVH refinement in automotive industry. This work pertains to a transmission gear whine issue encountered in prototype evaluations during a vehicle program development process. The effort centers itself on the optimization of transmission gear macroscopic and microscopic parameters to fix the issue which is deemed unacceptable for customers. Specifically, by using multi-body dynamics approach, this work carries out a transmission system whine noise simulation based on optimal gear macro parameter selection and micro tooth flank modification. The obtained results show that the proposed design changes could successfully resolve the issue, which is verified by subsequent test measurement and confirmed by subjective evaluations.
2016-04-05
Technical Paper
2016-01-1177
Aditya Dhand, Keith Pullen
Abstract There are different types of energy storage devices which are used in today’s hybrid and electric vehicles. Batteries, ultra capacitors and high speed flywheels are the most commonly used ones. While batteries and supercapacitors store energy in the form of electric energy, the flywheel (FW) is the only device that keeps the energy stored in the original form of mechanical energy the same as the moving vehicle. The flywheel needs to be coupled to the driveshaft of the vehicle in a manner which allows it to vary its speed independently of the moving vehicle in order to vary its energy content. In other words a continuously variable transmission (CVT) is needed. The common mechanical variators used in automotive applications, namely the rolling traction drives and the belt drives, have the disadvantage that their speed ratio range defined as the maximum to minimum speed ratio is generally not sufficient for flywheel energy storage system (FESS).
2016-04-05
Technical Paper
2016-01-1358
Jerry Lai, Youssef Ziada, Juhchin Yang
Abstract During the planetary gear assembly, staking is a widely-used method for affixing pinion shafts onto the position. A reliable staking process not only prevents the movement of shaft during transmission operation, but also minimizes the distortion of the assembly due to the staking process. The quality of staking operations is determined by the component designs, the process parameters, and the staking tool geometry. It would be extremely time-consuming and tedious to evaluate these factors empirically; not even mention the requirement of prototypes in the early stage of a new program. A Finite Element methodology is developed to simulate the complete staking process including shaft press in, staking, and after staking tool release. The critical process parameters, such as staking force, staking length, shaft and holes interference amount, etc., are then evaluated systematically.
2016-04-05
Technical Paper
2016-01-1378
Takanori Ide, Kentaro Toda, Yasunori Futamura, Tetsuya Sakurai
Abstract Efficient method to solve large-scale eigenvalue problem in vibration is presented. NVH (Noise, Vibration and Harshness) performance is an important quality measure of vehicles. Therefore, the reduction of vibration is one of the key considerations of new automatic transmission design. In addition, reduction of product design time is another important requirement. Computer Aided Engineering (CAE) is becoming a more important methodology to reduce product design time. However, computational time of eigenvalue problem takes long. We propose parallel eigenvalue computation (Sakurai-Sugiura method) for large-scale eigenvalue problems. This method has a good parallel scalability according to a hierarchical structure of the method. As the demonstrative problem, we consider large-scale computation of eigenvalue problem for AISIN AW FWD automatic transmission.
2016-04-05
Technical Paper
2016-01-1294
Jonggyu Kim, Pyoung Beom Kim, YoungChan Lee, Sunghee Jung, Byeong-Ug Choi
Abstract This study presents the NVH characteristics of a passenger vehicle with a three-cylinder engine and a Continuously Variable Transmission (CVT) and an optimization procedure to achieve balance between fuel economy and NVH. The goal of this study is to improve fuel economy by extending the lock-up area of the damper clutch at low vehicle speed and to minimize booming noise and body vibration caused by the direct connection of the engine and transmission. Resonance characteristics of the chassis systems and driveline have been studied and optimized by the experiment. NVH behavior of the vehicle body structure is investigated and modifications for refinement of booming and body vibration are proposed by simulation using MSC NASTRAN. Calibration parameters for CVT control are optimized for fuel economy and NVH.
2016-04-05
Technical Paper
2016-01-1172
Takashi Iwata, Kyosuke Mori, Taketoki Maruyama, Shinobu Nakamura, Yusuke Yoshida, Toshihiko Yamanaka
Abstract Recently, for the aspects of ecology and economy, fuel efficiency improvement demand has been increased globally. And, various types of hybrid systems have been suggested. In response to this market demand, AISIN SEIKI has been developing Synchronizer-less hybrid automated manual transmission (HV-AMT) system aiming excellent transmission efficiency, excellent agility, and shift change quality like a step automatic transmission (AT). This hybrid system is constructed based upon a parallel 2-axis manual transmission (MT) which originally has high transmission efficiency. The synchronizer system of a MT is replaced by a Dog clutch system which does not spoil the transmission efficiency and never makes failure in synchronization. This Dog clutch system includes a modified detent function, a shift actuator of linear motor, advanced function controls for a clutch and a shift actuator.
2016-04-05
Technical Paper
2016-01-1098
Jongsool Park
Abstract The market demands for CO2 reduction and fuel economy have led to a variety of new gear set concepts of automatic transmissions with 4 planetary gear sets and 6 shift elements in recent years. Understanding the relationship between the torque of clutch and brake and gear ratio in the design stage is very important to assess new gear set concepts and to set up the control strategy for enhancing shift quality and to reduce the heat generation of clutch and brake. In this paper, a new systematic approach is used to unify the relationship between torque and gear ratio during the gear shift for all multi-step planetary automatic transmissions. This study describes the unified concept model with a lumped inertia regardless of the specific transmission layout and derives the principal unified relationship equations using torque and energy analysis, which prove that the sum of brake torque is always gear ratio -1 in every in-gear.
2016-04-05
Technical Paper
2016-01-1100
Andrei Keller, Sergei Aliukov, Vladislav Anchukov, Stanislav Ushnurcev
Abstract The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-toweight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.
2016-04-05
Technical Paper
2016-01-1103
Andrei Keller, Sergei Viktorovich Alyukov
Abstract The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-to-weight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.
2016-04-05
Technical Paper
2016-01-1107
Jing Yuan
Abstract The belt clutching CVT drive has been developed for the scooter application. It utilizes the belt as a clutching mechanism instead of the traditional centrifugal clutch that is commonly employed in conjunction with the driven clutch of the drive train. By eliminating the centrifugal clutch, 48% mass reduction of the driven clutch has been achieved as well as cost saving. By placing the belt clutching directly at the engine crankshaft, fast throttle response and better vehicle acceleration/deceleration have been attained. The belt clutching mechanism demands a better performance belt to withstand the additional clutching induced wear and tear. The newly developed carbon cord belt, G Force™ C12, meets the challenge. The common edge cord pull-out failure mode is eliminated, and the overall wear is improved. An analytical program PTWork has been developed and proven to be instrumental in integrating CVT clutch hardware with the CVT belt.
2016-04-05
Technical Paper
2016-01-1092
Gabriela Achtenova, Jiri Pakosta
Abstract In the laboratories of CTU in Prague, an inertia test stand was recently built for endurance tests of the internal shift mechanisms of passenger cars. With regard to the instrumentation of the stand, it can be used also for determination of lost power of the not-loaded transmission. In this paper we present the values for the no-load losses measured during different conditions (temperature, shifted speed, speed of rotation) on the automotive mechanical gearbox for the transversal disposition of the drivetrain. For the further usage of the measured values is important to determine the proportion of the different sources of losses. We are mainly interested to identify the proportion of the churning losses and losses in the sealing, since these two losses remain the same, whatever the load of the gearbox will be. The losses of bearings on input and secondary shaft were calculated with the tool available from SKF.
Viewing 1 to 30 of 2848