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Viewing 1 to 30 of 2739
2015-06-15
Technical Paper
2015-01-2231
Masashi Arakawa, Miho Nakatsuka, Hiroo Yamaoka
To analyze gear transmitted vibration which occurs due to transmission error, a new prediction methodology is developed when vibration transmits through engine mounts from housing. This paper focuses on a left-hand engine mount and brackets which are assembled on a transmission housing of a compact FF vehicle connecting transmission housing to body structure. Thus a modeling technique dealing with the dynamic characteristic of mount rubber and its bracket is indispensable. A mount rubber is pre-loaded under power plant weight and undergoes from its initial shape to deformed one until reaching equilibrium state. To precisely predict a dynamic characteristic of mount rubber when the power plant is mounted in vehicle, we have to consider the deformed shape when pre-load is applied.
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
2015-01-1135
Karthik Bhargav Siriyapuraju, Viswasai Konduru, Prithiviraj Eswaramoorthy
Abstract The customer of today is sensitive towards shift quality. The demand is for a crisp and precise gear shift with low shift effort. The impulses from synchronizers make shifts feel notchy. After synchronization the blocker ring releases the sleeve. The sleeve then hits the teeth of the clutch body ring. The second impulse causes a phenomenon called double bump. This can be felt at the hand and makes a shift feel notchy or sluggish. An ideal way to overcome this is to optimize the detent profile. This paper explains in detail the various factors that contribute to the perceived shift feel. Various methods to optimize the forces on the knob by changing the detent profile are discussed. Gear Shift Quality Assessment (referred as GSQA henceforth) is a tool to acquire the required shift feel data. Using this tool shift efforts and kinematics of a 5 speed manual transmission are plotted for illustration.
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
2015-01-1089
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
2015-01-1092
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
2015-01-1095
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
2015-01-1102
Katsuhiko Ohishi, Toshihiro Uehara, Ichirou Kishigami
Abstract High fatigue strength is required for maraging steel for CVT belts. Two types of next generation maraging steels for CVT belts were studied using the following conditions, (a) increasing tensile strength, (b) increasing compressive residual stress on the nitrided surface, and (c) no addition of Ti. AlloyB (Fe-19%Ni-5%Co-5%Mo-1%Cr-0.8∼1.5%Al, %=mass%) with low Co and AlloyC (Fe-19%Ni-12.5%Co-5%Mo-0.5∼1%Cr,%=mass%) with high Co, were developed by additions of optimized amounts of Al and Cr, which are based on different strengthening ideas of Ti addition. These maraging steels showed tensile strengths and fatigue strengths equal to or better than those of conventional Ti-containing maraging steels.
2015-04-14
Technical Paper
2015-01-1108
Hongqing Chu, Yong Chen, Lishu Guo, Bingzhao Gao, Hong Chen
Abstract In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock.
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
2015-01-0978
Lori Lemazurier, Neeraj Shidore, Namdoo Kim, Ayman Moawad, Aymeric Rousseau, Phillip Bonkoski, Jeremy Delhom
Abstract Near-term advances in spark ignition (SI) engine technology (e.g., variable value lift [VVL], gasoline direct injection [GDI], cylinder deactivation, turbo downsizing) for passenger vehicles hold promise of delivering significant fuel savings for vehicles of the immediate future. Similarly, trends in transmissions indicate higher (8-speed, 9-speed) gear numbers, higher spans, and a focus on downspeeding to improve engine efficiency. Dual-clutch transmissions, which exhibit higher efficiency in lower gears, than the traditional automatics, and are being introduced in the light-duty vehicle segment worldwide. Another development requiring low investment and delivering immediate benefits has been the adaptation of start-stop (micro hybrids or idle engine stop technology) technology in vehicles today.
2015-04-14
Technical Paper
2015-01-1123
Jiangwu Zhang, Donghao Liu, Haisheng Yu
Abstract 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 increase the system efficiency. System dynamics and matching performance of the driveline including a compound planetary gear set for a single-mode hybrid electric vehicle are numerically investigated. The multi-degrees of freedom torsional vibration model for the full-hybrid vehicle driveline with the power split device is established by MATLAB/Simulink. For comparison of the natural characteristic, eigenfrequencies and mode shapes are determined with the aid of a further simplified single-track mechanical model under different operation modes. Then, numerical simulations of dynamics and kinematics of the driveline and the compound planetary gear set are carried out.
2015-04-14
Technical Paper
2015-01-1120
Siddhartha Singh, Sudha Ramaswamy
Abstract 1 The modern engine is capable of producing high torque and horsepower. Now the customer wants state of the art comfort and ergonomics.Thus the manufacturers are focusing on reducing the clutch pedal effort and providing a pleasurable driving experience. In heavy traffic conditions where the clutch is used frequently, the pedal effort required to disengage the clutch should be in comfortable range. Often drivers who drive HCV complain about knee pain which is caused due to high pedal effort, this occurs when ergonomics of ABC (accelerator, brake and clutch) pedals is not designed properly. Thus there is a need to reduce the driving fatigue by optimizing the clutch system. Latest technologies like turbo charging and pressure injection have increased the engine power and torque but have also led to increase the clamp load of clutch. Thus the release load required to disengage the clutch has also increased.
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
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
Abstract The hydraulic retarder is an important auxiliary braking device for the heavy vehicle, which has some characteristics, such as the big brake torque and long duration braking, when the vehicle is traveling in braking state. However, the transmission power loss will be produced when the vehicle is traveling in non-braking state. This transmission power loss is called Air-friction. Firstly, the air flow distribution characteristics of retarder cavity are studied by computational fluid mechanics, and the Air-friction characteristic in different conditions is analyzed. Then, according to the Air-friction characteristics for the condition of different filling density, a set of vacuum air loss reduction system is designed. Meanwhile, the test bench for retarder Air-friction is set up, the test data of the revolution speed, pressure in cavity and air loss resistance is obtained according to the test bench for hydraulic retarder.
2015-04-14
Technical Paper
2015-01-1132
Jiaxing Zhan, Mohammad Fard
Abstract The self-locking gear has great potential application in controlling the position stability of gearbox, which is a critical requirement in some precision machineries and instruments. This study provides important knowledge about the dynamic performance of self-locking gear pairs. An analytical model of variation ratio of contact length (VRCL) was established. The tooth root stress, bearing force, and axial acceleration of three self-locking gear pairs are investigated by using transient dynamic finite element analysis (FEA). The FEA results presented the influences of VRCL on the meshing performance of self-locking gear pairs. The obtained results provide significant knowledge for predicting the dynamic performance of self-locking gear pairs, optimizing their design parameters, and diagnosing possible design errors in self-locking gear pair design.
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
2015-01-1146
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
2015-01-1148
Xi Li, Weiguo Zhang, Jinning Li, Ming Jiang, Yunqing Zhang
Abstract A simulation model of the single cone synchronizer is presented using the dynamic implicit algorithm with commercial Finite Element Analysis (FEA) software Abaqus. The meshing components include sleeve gear, blocking ring and clutch gear, which are all considered as deformation body. The processes mainly contain the contact between sleeve teeth and blocking teeth, meshing period and the impact of sleeve teeth and clutch gear teeth, and these nonlinear contact steps are realized with Abaqus. In addition, a shift force derives from experiment is applied to the sleeve ring, and a moment is added to the clutch gear to realize the relative rotational speed. Based on the FEA model, the effect of the varied frictional coefficients between the cone surfaces of blocking ring and clutch gear on the synchronizer time and contact stress is discussed. Variation of stresses and contact force with respect to time are evaluated from this analysis.
2015-04-14
Technical Paper
2015-01-1141
Chengwu Duan, Farzad Samie, Kumaraswamy Hebbale, Dongxu Li, Chunhao Lee
Abstract For the conventional 6 speed automatic transmission with engine stop-start powertrain, an electrically-driven auxiliary pump is implemented to maintain the transmission line pressure as required to lock-up the CB1234 clutch during engine auto-stop conditions. Upon releasing the brake pedal, the transmission engages into first gear with the objective to accelerate the vehicle in a responsive manner. In this study, a novel normally-engaged dual-piston clutch concept is designed to keep the CB1234 clutch locked-up during engine auto-stop conditions with the intention to eliminate the auxiliary pump without compromising vehicle performance. This dual piston clutch concept requires a relatively low line pressure to release the normally-engaged clutch when needed, thus, minimizing the hydraulic pumping work.
2015-04-14
Technical Paper
2015-01-1119
Guangqiang Wu, Lijun Wang
The traditional automotive hydrodynamic torque converter (TC) is equipped with single-blade stator, at the suction side of which there is apparent boundary layer separation at stalling condition because of its large impending angle. Separation flow behind the suction side of stator blade will create large area of low-energy flow which blocks the effective flow passage area, produces more energy losses, and decreases impeller torque capacity and transmission efficiency. It is found be effective to separate the stator original single-blade into primary and secondary part, or use dual-blade one, which guide high-energy flow at the pressurized side of the primary blade to the suction side of the secondary blade and suppress the boundary layer separation effectively so that impeller torque capacity and torque ratio at low-speed ratio increase tremendously at the cost of little drop of maximum efficiency.
2015-04-14
Technical Paper
2015-01-0380
Stefania Falfari, Gian Marco Bianchi, Giulio Cazzoli, Federico Brusiani, Claudio Forte, Cristian Catellani
In PFI and GDI engines the tumble motion is the most important charge motion for enhancing the in-cylinder turbulence level at ignition time close to the spark plug position. In the open literature different studies were reported on the tumble motion, experimental and not. Research on the tumble motion generation at partial load conditions is rather infrequent. In the present paper the research activity on the tumble generation at partial load and very partial load conditions was presented. The added value of the analysis was the study of the effect of the throttle valve rotational direction on the tumble motion and the final level of turbulence at the ignition time close to the spark plug location. The focus was to determine if the throttle rotational direction was crucial for the tumble ratio and the turbulence level. The analyzed engine was a PFI 4-valves motorcycle engine. The engine geometry was formed by the intake duct and the cylinder. The CFD code was FIRE AVL code 2013.1.
2015-04-14
Technical Paper
2015-01-0212
Mohamed El Morsy, Gabriela Achtenova
Abstract An efficient condition monitoring system provides early warning of faults by predicting them at an early stage. When a localized fault occurs in gears, the vibration signals always exhibit non-stationary behavior. The periodic impulsive feature of the vibration signal appears in the time domain and the corresponding gear mesh frequency (GMF) emerges in the frequency domain. However, one limitation of frequency-domain analysis is its inability to handle non-stationary waveform signals, which are very common when machinery faults occur. Particularly at the early stage of gear failure, the GMF contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations. An effective signal processing method would be necessary to remove such corrupting noise and interference. In this paper, a new hybrid method based on optimal Morlet wavelet filter and autocorrelation enhancement is presented.
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
2015-01-1149
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.
2015-04-14
Technical Paper
2015-01-1625
Frederic Boissinot, Jerome Bellavoine, Andrew Shabashevich, Siegfried Puster
In today’s competitive automotive market, car manufacturers and transmission suppliers 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 and earlier in the development process. Until now, it has been difficult to respond to these requests as the calibration tasks linked to drivability are still mostly done in vehicles. This paper describes a new methodology designed to answer these challenges by performing automated shift quality calibration for transmissions prior to the availability of test vehicles. This procedure allows development of accurate and representative transmission calibrations focused on drivability by 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.
2015-04-14
Technical Paper
2015-01-0633
Fan Luo, Jinning Li, Xingxing Feng, Yunqing Zhang
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 synchronizer sleeve, outer ring and clutch gear 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 effects of stiffness of disk spring and length of energizing teeth of sleeve are studied.
2015-04-14
Technical Paper
2015-01-1240
James Kearns, Soon Park, John Sabo, Dusan Milacic
Paper Title: MMLV - Lightweight Transmission Components Author: John Sabo, Magna International Abstract: The Multi-Material Lightweight Vehicle (“MMLV”) is a lightweight vehicle development project between Ford and Magna International, 50% co-funded by US Department of Energy (DOE) and Canadian Provincial grants. The goal of the project is to use lightweight material systems and manufacturing technologies to achieve significant overall weight reduction and demonstrate viability of such design by component-level testing. This paper presents a summary of the MMLV design development for lightweight transmission and driveline components, supported by extensive use of CAE analysis and component-level testing of prototype parts. A total mass reduction of 14kg (13.8%) relative to the 2012 Fusion baseline vehicle transmission and driveline components was achieved.
2015-04-14
Technical Paper
2015-01-1143
Ivan Rot, Daniel Fritz Plöger, Stephan Rinderknecht
Abstract In this investigation two different nonlinear dynamic black box modelling approaches are compared. The purpose of the models is to reproduce the transient gearshift process. The models are used to compute the torque at the sideshafts, which is highly correlated to the gearshift comfort. The first model is a Gaussian process (GP) model. The GP is a probabilistic, non-parametric approach, which is additionally capable to compute the confidence interval of the simulated output signal. The second black box model uses the artificial neural net (ANN) approach. In addition to training algorithms the resulting model configurations for both black box approaches are shown in this investigation. Furthermore the empirical error of both modeling approaches is compared to the predictive variance of the GP model and to the intrinsic uncertainty of the gearshift process.
2015-04-14
Technical Paper
2015-01-1124
Gerrit Knabe, Markus Zahlten, Ferit Kücükay
Abstract In order to improve the acoustic comfort inside passenger cars in terms of transmission noise, a special method has been developed. For a structured and comprehensive analysis of the transmission noise, the generation and transfer mechanisms are divided into four separate but nevertheless connected parts. Although simulation and components tests are used to analyze vibration excitation which may cause rattle and the mechanisms causing rattle in detail [1, 2], they are not the main part of the analysis. The focus of this study is on the transfer of automotive transmission rattle and the passengers' perception. The noise characteristics, which can be specified using conventional analysis methods as well as assessments by test persons, are important for the transfer path of the disturbing noise. By combining different methods of transfer path analysis (TPA), direct airborne-sound transmission is identified as a significant transfer path of the rattling noise.
Viewing 1 to 30 of 2739