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Viewing 1 to 30 of 2752
2015-09-06
Technical Paper
2015-24-2530
Mohamed El Morsy, Gabriela Achtenova
A vehicle gearbox serves for torque and speed conversion with help of rotating elements. Therefor the gearbox experiences periodic excitation forces with a fundamental frequency following the rotation frequency. These excitation forces give rise to corresponding periodic response signals, i.e. signals having content at the fundamental (rotational) frequency and its harmonics. Order analysis is an analysis technique which is used to extract these harmonic orders from the response signals. This article intends to use the order tracking analysis for gearbox fault diagnosis under variable speed conditions to compare between healthy and faulty cases by using order extraction. Finally, determine maximum Root Mean Square (RMS) as severity index.
2015-07-01
Journal Article
2015-01-9143
Gabriel Pouliot, Marc-Olivier Lacerte, Jean-Sebastien Plante, Philippe Micheau
This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside Automated Manual Transmissions (AMTs) to perform seamless gear upshifts. Electric vehicles (EVs) with a single-ratio gearbox may provide high levels of smoothness, but using a multi-speed gearbox provides significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. AMTs can provide smooth shifts without torque interruption when coupled to a normally-open torque bypass clutch. However, conventional dry friction clutches are not best suited for such torque bypass due to wear and controllability concerns, while wet clutches would decrease powertrain efficiency due to viscous losses. An eddy current clutch would be highly controllable, simple to manufacture, low-cost, robust, and do not wear compared to friction clutches.
2015-06-15
Technical Paper
2015-01-2176
Rajkumar Bhagate, Ajinkya Badkas, Kiran Mohan
Abstract Gear rattle is an annoying noise phenomena of the automotive transmission, which is mainly induced by torsional fluctuation of engine. In this study, torsional vibration of 3 cylinder powertrain is analyzed and improved for reducing the gear rattle from transmission by using parametric optimization. One dimensional Multi-body mathematical model for the torsional vibrations of front wheel drive automotive drivetrain is developed and utilized for the optimization of sensitive parameters of the driveline. Second order differential equations of the mathematical model are solved by using MATLAB and the output response is validated with the test data. Parametric optimization is conducted by using design of experiment method. The updated model is further utilized for optimizing the flywheel inertia, driveshaft stiffness and clutch stiffness. Mathematical modelling and optimization process has helped to achieve NVH targets for driveline.
2015-06-15
Technical Paper
2015-01-2171
Winston Spencer, Djamel Bouzit, Joseph Pace, Sudeep Dhillon
Driveline plunge mechanism dynamics has a significant contribution to the driver's perceivable transient NVH error states and to the transmission shift quality. As it accounts for the pitch or roll movements of the front powerplant and rear drive unit, the plunging joints exhibit resisting force in the fore-aft direction under various driveline torque levels. This paper tackles the difficult task of quantifying the coefficient of static friction and the coefficient of dynamic friction in a simple to use metric as it performs in the vehicle. The comparison of the dynamic friction to the static friction allows for the detection of the occurrence of stick-slip in the slip mechanism; which enables for immediate determination of the performance of the design parameters such as spline geometry, mating parts fit and finish, and lubrication. It also provides a simple format to compare a variety of designs available to the automotive design engineer.
2015-06-15
Technical Paper
2015-01-2231
Masashi Arakawa, Miho Nakatsuka, Hiroo Yamaoka
Abstract To analyze vibration generated from the gears caused by meshing error, a new prediction methodology has been developed for vibration transmitted through the engine mounts from the transmission housing. This paper focuses on the left engine mount and brackets attached to the transmission housing of a compact front-wheel drive (FWD) vehicle that connect the transmission housing to the body structure. In this methodology, a modeling technique that incorporates the dynamic characteristics of rubber mounts and brackets is indispensable. A new simulation technique deals with a detailed rubber mount FE model that considers the contact area at the attachment point of the mount and brackets. The methodology is able to estimate vibration with high accuracy by taking into account dynamic characteristics such as surging for the rubber mount, and using the actual contact area confirmed by pressure sensitive paper for the vehicle FE model.
2015-06-15
Technical Paper
2015-01-2332
Jan Deleener, Akira Sekitou, Masanori Ohta
Abstract Shift quality of a gearbox is one of the most important items contributing to the overall subjective impression of driving comfort for a vehicle with a manual transmission. Often the transmission is the only point of attention for shift quality issues with a focus on the synchronizer being the main area of optimization. This is however not always sufficient. What the driver feels at the gear lever is a result of the interaction between the gear lever, the selector system, the transmission internals and the driveline. For most of these subsystems, well established models are available which can be used in early development to get a first idea of the shift quality. However, accurately representing the physical feel of the transmission cable, connecting the gearbox and the shifter, remains a challenge.
2015-06-15
Journal Article
2015-01-2261
Joseph Plattenburg, Jason Dreyer, Rajendra Singh
Abstract Combined active and passive damping is a recent trend that can be an effective solution to challenging NVH problems, especially for lightweight vehicle components that demand advanced noise and vibration treatments. Compact patches are of particular interest due to their small size and cost, however, improved modeling techniques are needed at the design stage for such methods. This paper presents a refined modeling procedure for side-by-side active and passive damping patches applied to thin, plate-like, powertrain casing structures. As an example, a plate with fixed boundaries is modeled as this is representative of real-life transmission covers which often require damping treatments. The proposed model is then utilized to examine several cases of active and passive patch location, and vibration reduction is determined in terms of insertion loss for each case.
2015-06-15
Journal Article
2015-01-2333
Brandon Sobecki, Patricia Davies, J Stuart Bolton, Frank Eberhardt
Abstract Component sound quality is an important factor in the design of competitive diesel engines. One component noise that causes complaints is the gear rattle that originates in the front-of-engine gear train which drives the fuel pump and other accessories. The rattle is caused by repeated tooth impacts resulting from fluctuations in differential torsional acceleration of the driving gears. These impacts generate a broadband, impulsive noise that is often perceived as annoying. In most previous work, the overall sound quality of diesel engines has been considered without specifically focusing on predicting the perception of gear rattle. Gear rattle level has been quantified based on angular acceleration measurements, but those measurements can be difficult to perform. Here, the emphasis was on developing a metric based on subjective testing of the perception of gear rattle.
2015-04-14
Technical Paper
2015-01-1737
Jean-louis Ligier, Mathieu Benoit, Sylvain Damaz
Abstract Today new automotive engine design is optimized in terms of mass. However, in terms of structural stiffness, optimizations mainly consider eigenfrequency criteria. But in assembly components with very low stiffness, cumulated microslip phenomena can occur when the structures are subject to cyclic loadings. In time and after a large number of cycles, macro-displacements can be observed between assembly components and then assembly failures will occur. Bush, plain bearing, roller bearing in conrod or in gearbox can be subject to this kind of problem. In this paper, after a short description of various mechanisms which can cause microreptation phenomena, two types of cumulated microslip occurring in the engine and the gearbox are presented. Behavior specificities will be highlighted to remind how unusual cumulated microslips are. Based on field data, it appears that the probability of both phenomena occurring is extremely low.
2015-04-14
Technical Paper
2015-01-0230
Shuhan Tang, Yanfang Liu, Xiao Han
Abstract As a significant control component of vehicles, automatic transmissions should have failure protection function. The failure protection function partly is determined by the hydraulic control system. However traditional design could not cover all of failures, and there is no general design method. A design method is proposed for designing the shift control oil circuit of the hydraulic control system with the failure protection function. The design method is applied to optimize the hydraulic control system of a six-speed automatic transmission. The function of the optimized hydraulic control system is confirmed by the dynamic simulation. The results show that the design method can simplify the hydraulic control system without losing any original functions. The proposed design method is proved to be suitable for all kinds of hydraulic control systems of automatic transmissions.
2015-04-14
Technical Paper
2015-01-0231
Qingkai Wei, Yulong Lei, Xingzhong Li, Boqin Hu, Zhengwei Liu, Bin Song
Abstract Gear-shift process of automatic transmission (AT) can be achieved with hydraulic control system which operates clutches or brakes' engagement or disengagement. According to the state of engagement elements, gear-shift process can be divided into torque phase and inertia phase. This article analyses gear-shift process of automatic transmission with the lever analogy and got the variation of the transmission's output torque. Then, the control principle of clutch to clutch shift is studied. This article takes power on up shift as study example and minimum of transmission output torque fluctuations during shifting as control target. Then this article analysis two control principles including inertia phase engine & transmission integrated control principle and entire shift process engine & transmission integrated control principle.
2015-04-14
Technical Paper
2015-01-1087
Juergen Greiner, Martin Grumbach, Albert Dick, Christoph Sasse
Abstract Market trends clearly demonstrate the ongoing worldwide acceptance and success of modern automatic transmission solutions (AT, CVT, DCT) in both passenger cars and light trucks. This success is based on the further development of the driving comfort, shifting dynamics and - most important - the fuel consumption reduction modern automatic transmission systems offer. First, key driveline parameters such as overall spread and number of ratio's are to be discussed. The optimum spread for the fuel efficiency is in the range of about 8 to 9 and can typically be achieved by 8 to 10-speed transmissions. This is because modern gasoline or diesel-engines have a rather flat characteristic fuel map. Therefore the inner efficiency of the future transmissions becomes increasingly important.
2015-04-14
Technical Paper
2015-01-1089
Ajay Vasantrao Shinde, Prashant Jha, Anshuman Dev
Abstract Transmission is the drive line of a vehicle. Road load requirement are fulfilled by transmission system. Selection of gear ratios in early stage of design based on simulated vehicle performance reduces the cost and time in product design cycle. Selection of gear ratios based on acceleration performance in 1st and 2nd gear, maximum speed of vehicle achieved in last gear and grade-ability in first gear is explained in this paper for AMT. Automated manual transmission is a recent trend in two wheelers that fulfills fuel economy requirement and increases driving comfort. Gear shift strategy for AMT is derived based on fuel economy or drivability. This paper addresses the shift strategy that targets drivability of vehicle. Simulation done in GT power is done with India driving cycle to derive gear number against vehicle speed.
2015-04-14
Technical Paper
2015-01-1090
Sachin Bhide
Abstract This paper presents a method to model the transmission mechanical power loss for the unloaded and loaded losses on a planetary gearset. In this analysis, the transmission losses are differentiated into losses due to fluid churning; losses due to fluid shear between the walls of rotating parts; losses due to fluid shear between motors' stator and rotor and losses due to the meshing of gearsets while transferring torque. This transmission mechanical power loss model is validated with test data that was obtained by independently testing an eVT transmission. The mechanical power loss model mentioned in this paper was constructed to accurately represent the test setup. From the correlation with the test data, it can be inferred that the transmission losses can be modeled within an error of 3% in the relevant region of output velocity for use in performance and fuel economy simulations.
2015-04-14
Technical Paper
2015-01-1092
Gabriela Achtenova, Ondrej Milacek
Abstract The purpose of the article is to describe different possibilities of the innovative concept of the closed-loop test rig. The performed tests will be demonstrated with the example of measured data. Firstly the article will describe in detail the design of the test stand and both torque units. The power flow in the closed-loop circuit will be described and measured to find out the power losses of all parts. The measurement will be done for manual and planetary pretensioning mechanism. The comparison of the overall efficiency and demanded power for both torque units will be given. For evaluation of gearbox efficiency, the magnitude of power losses will be evaluated for different revolutions, torque levels and shifted speeds. For a long term tests, the unmanned operation is prepared. For this purpose is the stand equipped with electromechanical shift robots. The description of its concept and functioning will be part of the paper.
2015-04-14
Technical Paper
2015-01-1091
Fumikazu Maruyama, Moichio Kojima, Tomoyuki Kanda
Abstract A new CVT that is lighter in weight and more highly efficient than the previous CVT for use in compact vehicles has been developed and used in the 2014 model year FIT. The allowable torque capacity was expanded to that of the 1.8-L engine class, making this CVT usable in a greater number of vehicle models. The ratio coverage was also expanded and the transfer efficiency was increased to enhance fuel economy and drivability. Integration of hydraulic control system functional parts and reduction in the number of case component parts were carried out as structural modifications. Pulley side pressures were also reduced by the use of new CVT fluid so that the pulley could be made more compact and lighter in weight. Enhancements were made in CVT shift control, providing more acceleration considered from the driver's acceleration demand and more linearity between vehicle speed and engine speed than in previous models.
2015-04-14
Technical Paper
2015-01-1096
Robert Lloyd
Abstract The frequent stops of the typical postal delivery vehicle make it an attractive application for regenerative braking. The hydro-mechanical automatic transmission described in SAE paper 2014-01-1717 contains all the functions necessary to implement hydraulic regenerative braking including the accumulator and reservoir. This paper describes the substitution of the hydro-mechanical transmission for the present transmission of the postal LLV vehicles and estimates the performance benefits. The result represents a low impact path for the US Postal Service to extend the useful life of the LLV vehicles and increase the mpg by approx. 100%. A cost comparison between a convention ICE mid-sized passenger sedan and a similar size gas/hydraulic hybrid vehicle illustrates the cost advantage of the hydraulic approach using the new transmission design. Besides lower cost, the vehicle will have greater initial acceleration and 25%+ better mpg.
2015-04-14
Technical Paper
2015-01-1095
Makarand Kumbhar
Abstract Transmission designs over the years have evolved significantly achieving more efficiency in terms of fuel economy, comfort and reduction in emissions. This paper describes a Dc motor based E-shift mechanism which automates an existing manual transmission and clutch system to give comfort and ease for gear shifting. The basic idea of E-shift mechanism is to make hassle free gear shifting of manual transmission at sole command of driver without any control strategy for automatic shifting as in case of Automated Manual transmission (AMT). The E-shift mechanism will eliminate the manual efforts required for pressing clutch pedal and shifting gear, giving more ease while driving. The developed mechanism can be retro fitted on existing manual transmission without any major modification at lower cost. The E-shift mechanism uses two actuators for gear shifting and one actuator for clutch actuation.
2015-04-14
Technical Paper
2015-01-1101
Jun Hakamagi, Tetsuya Kono, Ryoji Habuchi, Naoki Nishimura, Masahiro Tawara, Naoki Tamura
Abstract In response to increasing demands for measures to conserve the global environment and the introduction of more stringent CO2 emissions regulations around the world, the automotive industry is placing greater focus on reducing levels of CO2 through the development of fuel-efficient technologies. With the aim of improving fuel economy, a new continuously variable transmission (CVT) has been developed for 2.0-liter class vehicles. This new CVT features various technologies for improving fuel economy including a coaxial 2-discharge port oil pump system, wider ratio coverage, low-viscosity CVT fluid, and a flex start system. This CVT is also compatible with a stop and start (S&S) system that reduces fuel consumption by shutting off the engine while the vehicle is stopped. In addition, the development of the CVT improves driveability by setting both the driving force and engine speed independently.
2015-04-14
Journal Article
2015-01-0519
Susumu Maeda, Atsushi Kobayashi, Yuichiro Shimizu, Masao Kanayama, Masato Yuya, Hideki Imataka
Abstract A new nitriding technology and material technology have been developed to increase the strength of microalloyed gears. The developed nitriding technology makes it possible to freely select the phase composition of the nitride compound layer by controlling the treatment atmosphere. The treatment environment is controlled to exclude sources of supply of [C], and H2 is applied as the carrier gas. This has made it possible to control the forward reaction that decomposes NH3, helping to enable the stable precipitation of γ′-phase, which offers excellent peeling resistance. A material optimized for the new nitriding technology was also developed. The new material is a low-carbon alloy steel that makes it possible to minimize the difference in hardness between the compound layer and the substrate directly below it, and is resistant to decline in internal hardness due to aging precipitation in the temperature range used in the nitriding treatment.
2015-04-14
Technical Paper
2015-01-0633
Fan Luo, Jinning Li, Xingxing Feng, Yunqing Zhang
Abstract The structure of a classic self-energizing synchronizer is presented, and a simulation model is developed for analyzing the synchronizer performance. The self-energizing synchronizer has a disk spring and several energizing teeth on the sleeve for increasing the shift force. Besides, the asymmetric arrangement of chamfer teeth is applied to increase the torque for rotating ring and shift gears smoothly. The parameterized model of the typical synchronizer is developed with ADAMS for studying the synchronizer performance. In order to truly reflect the reality, the teeth of the claw plate are connected to the gear ring through bushing force alone, and the stiffness coefficient are obtained through the analysis of finite element model. Based on the dynamic model, the behavior of synchronizer with asymmetric arrangement of chamfer teeth, and the energizing effect of stiffness of the disk spring are studied. The simulation results can be used to design the synchronizer.
2015-04-14
Technical Paper
2015-01-1634
Toru Ishino, Shinichi Takai
Abstract When selecting a transmission gear, it has been standard to shift by operating a lever-type gear selector, but with advances in transmission technology and vehicle control, there is currently demand for technical progress in the operating method of the gear selector, and a good balance between intuitive operation by users and prevention of accidental operation is required. The authors have developed a push button-type electrically controlled gear selector that makes shifting easy to master and enables intuitive operation. A push button-type shifter should essentially be suitable for intuitive operation, but difficulty in distinguishing between selections has been an issue. However, we posited that distinguishing gear position selections by differentiating button operation direction as well as button positioning and shape could be implemented effectively.
2015-04-14
Technical Paper
2015-01-1625
Frederic Boissinot, Jerome Bellavoine, Andrew Shabashevich, Siegfried Puster
Abstract Today, OEMs are challenged with an increasing number of powertrain variants and complexity of controls software. They are facing internal pressure to provide mature and refined calibrations earlier in the development process. Until now, it was difficult to respond to these requests as the drivability's calibration tasks are mostly done in vehicles. This paper describes a new methodology designed to answer these challenges by performing automated shift quality calibration prior to the availability of vehicles. This procedure is using a powertrain dynamometer coupled with a real-time vehicle dynamics model. By using a Power Train Test Bed (PTTB), a physical vehicle is not required. As soon as the vehicle dynamics model and its parameters have been defined, it can be simulated on the PTTB and drivability calibrations can be developed. A complete powertrain is coupled with low inertia and highly dynamic dynamometers.
2015-04-14
Technical Paper
2015-01-0228
Francesco Braghin, Francesco Salis
Abstract The objective of this study is to demonstrate the design and construction of an innovative active gear-shift and clutch for racecars, applied to a Formula Student car, based on the use of DC gear-motors. Racecars require extremely quick gear-shifts and every system to be as light as possible. The proposed solution is designed to reduce energy consumption, weight and improve gear-shift precision compared to traditionally employed electro-hydraulic solutions, although maintaining state of the art performances.
2015-04-14
Technical Paper
2015-01-0517
Masaaki Kawahara, Noriaki Katori, Tatsuya Koyama
Abstract The friction pattern on the chamfers of sleeves and dog gears is a combination of peeling and adhesive wear caused by the formation and propagation of fine cracks. The effect of additional elements on wear were checked by making a test apparatus capable of performing evaluations on test pieces equivalent to those using actual parts. The results showed that the addition of B, Ti-Nb helped improve wear resistance. This is attributed to enhanced toughness and reduced peeling due to the formation of a texture. A 45% reduction in wear was achieved in actual parts tests on steel with added B, Ti-Nb.
2015-04-14
Technical Paper
2015-01-1303
Wenli Li, Xiao-Hui Shi, Dong Guo, Peng Yi
Abstract This paper discusses the development of engine and vehicle model for performing dynamic emulation experiments on vehicle transmissions. In order to reduce costs and shorten new vehicle development cycle time, vehicle simulation on the driveline test bench is an attractive alternative at the development phase to reduce the quantity of proto vehicles. This test method moves the test site from the road to the bench without the need for real chassis parts. Dynamic emulation of mechanical loads is a Hardware-in-the-loop (HIL) procedure, which can be used as a supplement of the conventional simulations in testing of the operation of algorithms without the need for the prototypes. The combustion engine is replaced by an electric drive dynamometer, which replicates the torque and speed signature of an actual engine. The road load resistance of the vehicle on a real test road is accurately simulated on Load dynamometer.
2015-04-14
Technical Paper
2015-01-1240
James Kearns, Soon Park, John Sabo, Dusan Milacic
Abstract This paper details the lightweighting efforts of the Ford Research & Advanced Transmission team as part of the Multi Material Lightweight Vehicle Project. The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three cylinder engine resulting in a significant environmental benefits and fuel consumption reduction.
2015-04-14
Technical Paper
2015-01-1153
Kingsly Samuel, David Brigham, Mark Jennings
Abstract The powersplit transaxle is a key subsystem of Ford Motor Company's hybrid electric vehicle line up. The powersplit transaxle consists of a planetary gear, four reduction gears and various types of bearings. During vehicle operation, the transaxle is continuously lubricated by a lube oil pump. All these components consume power to operate and they contribute to the total transaxle losses which ultimately influences energy usage and fuel economy. In order to enable further model-based development and optimization of the transaxle design relative to vehicle energy usage, it is essential to establish a physics-based transaxle model with losses distributed across components, including gears, bearings etc. In this work, such a model has been developed. The model accounts for individual bearing losses (speed, torque and temperature dependency), gear mesh losses, lube pump loss and oil churning loss.
2015-04-14
Technical Paper
2015-01-1146
Matthew Barr, Krishnaswamy Srinivasan
Abstract In this paper, a new algorithm for the off-line estimation of wet clutch friction parameters is proposed for automotive transmissions, motivated by the usefulness of such an algorithm for diagnosing the condition of the clutch and transmission fluid in service. We assume that clutch pressure is measured, which is the case in dual clutch transmissions (DCT). The estimation algorithm uses measured rotational speeds and estimated accelerations at the input and output sides of a clutch, measured clutch pressures, and a simplified dynamic model of clutch friction to estimate the viscous and contact components of clutch friction torque. Coefficient of friction data is generated using the contact friction torque. A Stribeck friction model is fit to the data, and parameters in the model are then calculated by applying linear least squares estimation.
2015-04-14
Technical Paper
2015-01-1149
Donghao Liu, Haisheng Yu, Jiangwu Zhang
Abstract Electrification of the automobile propulsion system can improve the energy efficiency and reduce the environmental pollution. A novel single-mode compound split hybrid transmission with a compound planetary gear set and two brakes has been studied, which has more freedom of control to improve the system efficiency. With different activations of the two brakes, different working modes can be obtained. The kinematics and kinetics relationships of the compound planetary gear set are analyzed firstly. Then the kinematics and kinetics of the transmission in the three different operation modes are respectively presented by the numerical method and lever method. Besides, the power flow of the transmission in different modes is analyzed. It is demonstrated by analyses that the compound power-split hybrid transmission has advantages of configuration, control and energy efficiency over the mainstream products on the market.
Viewing 1 to 30 of 2752