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Viewing 1 to 30 of 2878
2017-01-10
Technical Paper
2017-26-0058
Mirko Leesch, Erik Schreiterer, Gitesh Mutha
IAV developed a complete new dual-clutch transmission (DCT) system with focus on flexible usage and costs. As an entry level DCT the design is made for an east-west installation with maximum 200 Nm input torque which could be easily adapted between 100 Nm and 300 Nm. Furthermore the transmission can deliver 6 and 7 speeds with state-of-the-art, robust design solutions and future-oriented reverse gear design with engaged countershafts. The distance between the input shaft and the differential can be changed between 170 mm and 215 mm without changes in the gear set. This is an edge breaking advantage compared to state-of-the-art systems. Beside this flexibility the transmission can realize a first gear ratio from 12.2 to 18.5 and a total ratio spread from 4.4 to 8.5.
2017-01-10
Technical Paper
2017-26-0088
Christoph Danzer, Jens Liebold, Erik Schreiterer, Jörg Mueller
Currently known hybrid systems are technically complex and cost-intensive and referring to this for many end customers not available. Under this boundaries IAV has developed a cost optimal minimal concept of an efficient and modular powertrain platform for electric and hybrid vehicles. The system based on one unity gear set for up to three speeds, which enables seamless shifting with only one friction based clutch. With this platform powertrain units can be realized by using a maximum number of carry over parts (COP) for electric vehicles as well as for powerful hybrids. The derivable hybrid powertrains of the platform system is designed for 48V electric motors which enables the maximum cost potential in combination realized gear set and transmission technology. The real simple powertrain platform concept is furthermore scalable for different vehicle segments optionally with or without a hybrid option.
2017-01-10
Technical Paper
2017-26-0036
Ingo Steinberg, Dan Freiholtz, Gereon Hellenbroich
In India, the market demand for passenger cars with automated manual transmissions is steadily increasing. So far, the most successful vehicles addressing this trend use magnitude as the sales of vehicles with manual transmissions. Since customers are expecting even smoother vehicle operation, the next anticipated step is the move to automatic transmissions without any torque interrupt during gear shift. This can favorably be addressed with the dual clutch transmission technology. Re-utilization of already existing manufacturing facilities is possible with the retention of the lay-shaft design. Dual clutch transmissions offer driving characteristics, including vehicle launch, which are very similar to the behavior of vehicles with manual transmissions. This applies also to the fuel economy. Against this background, this article introduces an all new concept for a very cost efficient dual clutch transmission family for transversal, transaxle powertrains.
2017-01-10
Technical Paper
2017-26-0101
Jakob Howard, Mike Savage
Mild-hybridisation of conventional powertrains is set to become commonplace over the next 5 years, providing a proportion of the on-cycle and real-world CO2 benefits of a high-voltage hybrid at a far lower cost. However, the majority of this focus is around engine-related systems such as belt starter-generators and electric-superchargers. Design studies and simulations have shown that hybridising elements of the transmission system can extend the efficiency gains of engine based mild-hybrid and stop-start systems. Equally important, is the potential for a transmission integrated electrical system to support value-adding features such as electric creep, engine-off coasting or electric torque support for manual or automated manual transmissions, which can either further justify or partially offset the additional cost of the hybrid system.
2016-11-08
Technical Paper
2016-32-0021
Stephen Gurchinoff
Abstract This technical paper will provide supporting lubricated test data for the use of thermoplastics like polyamide-imide (PAI) and polyetheretherketone (PEEK) in demanding wear applications at temperatures up to 285°C and pressure velocity exceeding one million psi·ft/min. Applications include needle bearing replacement in transmissions, journal bearings, pumps, marine lower units, continuous variable transmissions, and others. These materials have been used in automotive transmission applications for over 20 years and can be similarly used in small engine applications. By using a thermoplastic, applications benefit through reduced noise and vibration harshness, reduced space, and reduced weight. Mechanical property differences throughout operating temperatures will also be reviewed.
2016-11-08
Journal Article
2016-32-0036
Takamori Shirasuna, Ryoh Hatakeyama, Yukio Sakai
Abstract A simulation tool has been developed that can be used to estimate a fuel economy while driving in a mode test of a motorcycle equipped with a continuously variable transmission (CVT) at an early stage of development. For a precise estimation of a mode fuel economy, it is necessary to accurately estimate the CVT ratio, the engine speed, and the crankshaft torque during driving in a mode. To achieve this, this study has generalized the transmission efficiency of a CVT system. This study has also derived developed balance equations that can take into account the transmission efficiency of CVT and the slippage that occurs when the centrifugal clutch is about to be engaged. In the proposed method, the pulley ratio of CVT, the engine speed, and the torque at the crankshaft were obtained first by solving the developed balance equations at discrete times during driving in a mode.
2016-10-17
Technical Paper
2016-01-2311
Arun Prasath G, Saravanan Duraiarasan, R Govindarajan
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 difficult 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
Abstract 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. Typically 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 clutches and the torque converter clutch. 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. Changes in the friction system over time that result in a lowering of the friction level, particularly at higher sliding speeds, compromise the performance of both types of clutches.
2016-10-17
Technical Paper
2016-01-2207
Elizabeth Schiferl, Timothy N. Hunt, Robert Slocum
Abstract With government mandates, original equipment manufacturers are increasingly focusing on fuel economy and finding efficiency gains throughout the vehicle. Lubricant companies have been asked to design fluids that aid in this effort. Demonstrating real gains becomes 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 was encountered when testing automatic transmission fluid efficiency within a full vehicle test. While it is well known that variability in testing conditions such as engine load or vehicle speed will lead to variability in results, the magnitude of their impact on average throughout the test cycle suggests that repeat testing may not be sufficient to guard against improper conclusions.
2016-10-17
Technical Paper
2016-01-2343
Mark Devlin, Darryl Williams, Michael Glasgow, Karen Hux, Aaron Whitworth, Timothy Cameron
Abstract 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
2016-01-2357
Onkar P. Gurav, Santosh Deshmane
Abstract 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 has 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. Customer’s 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
2016-01-2356
Shaopeng Tian, Geng Li, Tongliang Que
Abstract This paper mainly researches transmission efficiency (TE) of mechanical transmission in relation to the temperature of lubricating oil. Firstly the formula of TE is calculated about the kinematic viscosity of lubricating oil, then analyze the relationship between kinematic viscosity and temperature of lubricating oil, and finally the formula of TE which is related to the oil temperature is put forward. In order to verify the theoretical formula, the test bench for mechanical transmission is designed, which is used to research the N109 transmission of one mini car. The bench can be used to measure the curve of TE under different speed , load and lubricating oil temperature. The optimum operating temperature of the transmission is obtained by analyzing the measured data and theoretical calculation results. The test bench adopts 2 AC asynchronous motors to respectively simulate the driving and load performance of a vehicle.
2016-10-17
Technical Paper
2016-01-2353
Kazunori Harima, Shinji Tsuchiya, Takuro Morino, Yuji Nagasawa
Abstract A CVT belt is composed of multiple elements and layered rings. Each of these component parts generates loss, including relative slippage caused by the geometrical relationship between the elements and innermost ring layer. An effective way of increasing CVT efficiency is to reduce this slippage. However, since the relative slippage also controls whether the rings transmit constant torque at all times, reducing the slippage will also have an effect on the torque transmission performance of the rings. Therefore, to improve CVT efficiency by reducing the relative slippage, it is first necessary to analyze the changes to torque transmission. However, this slippage is a phenomenon of the inner portion of the belt and it is extremely difficult to identify the internal thrust force when actual load is applied.
2016-10-17
Journal Article
2016-01-2205
Chris McFadden, Kevin Hughes, Lydia Raser, Timothy Newcomb
Abstract 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. 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 ATFs. All fluids had conductivities ranging from 0.9 to 8x10-9 S/cm at 100 °C and can be considered 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. We find that more polar additives have a larger effect on conductivity on a normalized (per weight %) basis.
2016-09-27
Technical Paper
2016-01-8060
Samson Rajakumar
There has been immense focus on Gear Shift Quality as it is seen as an important factor for subjective evaluation of driving comfort of a vehicle with manual transmission. Synchronizer and driveline stiffness optimization is often the only area of focus for gear shift quality during early design stage. Proven Simulation models are already available for predicting the effect of synchronizer and driveline stiffness. Though Gear shift cable also has a significant effect on gear shift quality, neither design guidelines nor simulation models are available for predicting gear shift cable performance. Designers have relied on physical approach to establish cable routing, since cable routing cannot be predicted on virtual vehicle. In design phase cable routing is imagined and modeled in CAD using constrained curve geometry and later on established by physical trials on vehicle with various cable lengths, routing paths and clamp positions.
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.
2016-09-27
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
2016-01-8114
Massimiliano Ruggeri, Pietro Marani, Michele Selvatici
Abstract Stationary (parking) brake is a very important and safety critical function in many classes of machines. The new transmissions and the “by wire” systems increase the criticality of the role of stationary brake, as it is also an emergency (secondary) brake, and it’s often used to hold the vehicle when the transmission is not locking the wheels. As an example, dual clutch and power-shift transmission gear systems, as well as hydrostatic transmissions under certain circumstances, are often unable to hold the vehicle stopped and this function is provided by the stationary brake. Due to the main need of having the brake actuated when vehicle is stopped, without any hydraulic and electric power, the brake configuration is normally a “negative” configuration, usually called “spring applied” because of the actuator configuration, but this configuration causes the brake actuation when de-energized, even in case of system failure.
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
2016-01-8019
Marius-Dorin Surcel, Adime Kofi Bonsi
Abstract 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 performance was assessed on various road profiles only. The SAE Fuel Consumption Test Procedure (J1526) was used for constant high speed fuel consumption track test evaluations. The direct-drive transmission tractor consumed less than the overdrive transmission tractor, even though it was heavier. The testing on various road profiles was conducted using a towing dynamometer, for comparing the dynamic capability of the tractors when simulating the same towing load on two hilly road profiles: the Townes Pass path (in the Rocky Mountains) and the Saguenay path (in the Saguenay region of Quebec). Each tractor was to haul the set load along the given path while trying to attain 90 km/h speed.
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.
2016-06-17
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
2016-01-0003
Alberto Taraborrelli, Francesco Braghin
Abstract This paper reports the studies, design and developments of an electronic electro-actuated gearshifter installed on the DP7, which is Politecnico di Milano car that took part at Formula SAE 2015 competitions in Hockenheim and Varano dè Melegari. The original idea was born to replace the hydraulic gearshift system used until 2011 because of its high weight and cost. After many evaluations about the kind of technology to use, made by previous team members in the electronic department, the final project was a fully electric shifter. This system has proven its qualities among which are lightness and low cost.
2016-04-05
Technical Paper
2016-01-0422
Robert A. Smith, Christopher Rudzinskas
Abstract Samples of 33% glass filled and unfilled poly(butylene terephthalate) [PBT] and nylon 66 (PA66) were injection molded into bars,which were immersed in common engine and powertrain fluids: antifreeze, motor oil and automatic transmission fluid for 25 days. Fluid uptake was measured at 1, 7, 18, and 25 days by gravimetry. Both PBT samples absorbed 0.2-0.25% antifreeze and 0.05 - 0.10% motor oil and automatic transmission fluid (ATF). Both DSC and DMA analysis showed no disruption of polymer thermal transitions or storage moduli. The glass filled PA66 sample absorbed 2.5% antifreeze and 0.25-0.3% of motor oil and ATF and showed an 80°C reduction in the tan delta maximum on DMA. The unfilled PA66 sample absorbed 7% antifreeze and 0.2-0.3% of motor oil and ATF also showed a tan delta maximum 80°C less than the unexposed control. Creep analysis was conducted on the unfilled nylon sample and compared to a virgin material.
2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei Wu, Xiang Chen
Abstract The nonlinear characteristics impact of multi-staged stiffness clutch damper on the vehicle creeping is investigated by using the lumped-parameter modeling method as a certain mass-production passenger sedan is taken as the research subject. Firstly, a quasi-transient engine model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is acquired and as the input excitation to the driveline system. Secondly, a 12-DOF (Degree of Freedom) nonlinear and branched powertrain system and vehicle longitudinal dynamics model is established. The differential mechanism characteristics and dynamic tire property based on the LuGre tire model are considered. Then, for a traditional two-staged stiffness clutch damper in consideration of hysteresis characteristics, vehicle powertrain system responses in both the time and frequency domain are obtained.
2016-04-05
Technical Paper
2016-01-1685
Sayaka Tamura, Tsutomu Yoshinari
Abstract A three-motor hybrid system suitable for a super sports car was developed. This system features high power, light weight and high response, and has high cooling performance for high-load operation such as circuit driving. The power plant drives the rear wheels using the combination of a midship-mounted V6 twin-turbo engine, the direct drive motor of a hybrid system mounted directly on the engine, and a 9-speed dual-clutch transmission (DCT). The front wheels are driven by a twin-motor unit (TMU), and the size and weight of the Intelligent Power Unit (IPU) that supplies electric power to the TMU has been reduced to enable mounting behind the seats inside the cabin. In addition, the IPU uses air-conditioner cooperative cooling to enhance the cooling performance. As a result, assist is performed even during high-load operation.
2016-04-05
Technical Paper
2016-01-0089
Mohamed Samy Barakat, Mohamed Abdelaziz
Abstract This Application is using Multilayer Perceptron Algorithm to predict the shifting gear timing based on throttle percentage, vehicle velocity, time history and engine speed, in order to enhance the fuel efficiency, shifting time, power loss and driver’s comfort during shifting. The model makes no assumptions about how transmission performance aspects like gears slipping time or the existence of distinct environments like high temperature affects the power train system performance. Instead, the model can learn to model any type of distortion or additive noise in the sensor data; induced in the CAN protocol, through sufficient training data characterization. The network will be implemented on an AMESim model to characterize the operating temperatures and optimize the gearbox design to work with an optimal temperature and advance to this temperature during operation.
Viewing 1 to 30 of 2878