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Viewing 1 to 30 of 2750
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.
2015-06-15
Technical Paper
2015-01-2332
Jan Deleener, Akira Sekitou, Masanori Ohta
Shift feeling is an important comfort attribute for manual transmission driven vehicles. For front-wheel-drive vehicles, there are 3 main parts of interest: the gearbox, the shifter and the shift cable. Often only a test based evaluation process on the actual assembly is available in the later stages of development. In order to frontload the shift feeling evaluation a virtual simulation process is required. For the shift lever and the gearbox there are well established models available. With 3D multibody models or even 2D planar models the effect of kinematics and compliances like connection stiffness and friction are already studied today. However, the modelling of the transmission cable, connecting the gearbox and the shifter remains a challenge to accurately represent the physical feel. By experience it was known that the 3D positioning and curvature of the cable affected the friction force and therefore the shift feeling.
2015-06-15
Journal Article
2015-01-2261
Joseph Plattenburg, Jason Dreyer, Rajendra Singh
Combined active and passive damping is an emerging trend as it should 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 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. Further scientific studies include a bench experiment that determines frequency dependent properties of the viscoelastic damping material. 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
Component sound quality is an important factor in the design of competitive diesel engines. One component noise source 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.
2015-06-15
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
2015-01-2176
Rajkumar Bhagate, Ajinkya Badkas, Kiran Mohan
Gear rattle is an annoying noise and vibrations phenomena of the automotive driveline, which is mainly controlled by the engine’s torque variations creating the source for torsional fluctuations. In the current work, torsional vibrations are analyzed for improving comfort of the drivetrains. A 6 DOF, 1-D multibody mathematical model for the torsional vibrations of front wheel drive automotive drivetrain is developed and utilized for the optimization of sensitive system parameters for reducing the driveline rattle. Second order differential equations of the mathematical model are solved by using MATLAB and the output response is validated with the testing data. The model is further utilized for optimizing the flywheel inertia and clutch stiffness which are considered to be most sensitive parameters for reducing the input excitations to transmission.
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
2015-01-1143
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
2015-01-1135
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
2015-01-1123
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
2015-01-1104
Patrick Sexton, Robert A. Smithson, Gordon McIndoe
Abstract In order to introduce Dana's Variglide Continuously Variable Planetary (CVP) technology to the mobility industry, Dana has produced demonstrator transmissions for use in a rear wheel drive C-class car and in a fork lift truck. The intention is to illustrate how the CVP can be combined with conventional transmission technology to produce either a continuously variable transmission with the ratio range comparable to that of the latest step ratio transmissions, or used in a simple IVT configuration for off-highway applications. The co-axial design of the CVP allows it to package well into current drivetrain solutions. The ratio control of the device is fast, precise, and stable and the CVP does not require high power consumption for clamping. Multiple power flow configurations of the CVP are shown to blend well with current conventional transmission technology as well as future hybrid configurations.
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
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
2015-01-1092
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
2015-01-1090
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
2015-01-1089
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
2015-01-1153
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
2015-01-1303
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
2015-01-0633
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
2015-01-1216
Dafeng Song, Chang Zhang, Nannan Yang, Mingli Shang, Yujun Peng
Abstract Hybrid Electric Vehicles with a power split system provide a variety of possibilities to promote the fuel economy of vehicles and better adapt to various driving conditions. In this paper, a new power split system of a hybrid electric bus which consists of double planetary gear sets and a clutch is introduced. The system is able to decouple both the torque and speed of the engine from the road load, which makes it possible for the engine to operate on its optimal operation line (OOL). Considering the features of the system configuration and bus driving cycle, the driving mode of the bus is divided into Electric Vehicle (EV) mode, Electric Variable Transmission (EVT) mode and Parallel mode. By controlling the engagement of the clutch at high vehicle speed (after the mechanical point), the system operates in the parallel mode rather than EVT mode.
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
2015-01-0228
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
2015-01-0231
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
2015-01-0230
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
2015-01-1737
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
2015-01-1214
Zhiguo Zhao, Chen Wang, Tong Zhang, Xianjun Dai, Xiyue Yuan
Abstract A novel compound power-split hybrid transmission based on a modified Ravigneaux gear set is presented. The equivalent lever diagrams are used to investigate the electric operating modes for the hybrid powertrain, and then its dynamic and kinematic characteristics as well as efficiency characteristics are described in equations. A brake clutch mounted on the carrier shaft is proposed to enhance the electric driving efficiency for the hybrid transmission. Three types of electric operating mode are analyzed by the simplified combined lever diagrams and the system efficiency and torque characteristics for these electric operating modes are compared. A major influence on output torque of the hybrid transmission derived from the torque capability of motors and brake clutch is depicted.
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
2015-01-1109
Yulong Lei, Ke Liu, Yao Fu, Ge Lin, Bin Song
Abstract This investigation presents a methodology to develop and optimize shift process control strategy to improve shift quality as perceived by drivers during power-on upshift events for Dual Cultch Transmission (DCT) vehicles. As part of the first study, the main factors affecting shift quality during shifting process under typical working conditions are analyzed. And taking the power-on upshift as example, dynamic model of DCT shifting process is build. An Integrated control strategy is proposed for power-on upshift, which during torque phase slipping revolving speed controller is adapted to harmonically control two clutches power switching process, and during Inertial phase engine torque is regulated to synchronize with the value of target gear while holding the oncoming clutch pressure. Oncoming clutch oil pressure gradient in torque phase and engine torque reducing target decrement in inertial phase are chosen as controlled quantity.
2015-04-14
Technical Paper
2015-01-1119
Guangqiang Wu, Lijun Wang
Abstract The traditional automotive torque converter (TC) is equipped with a single-blade stator, at the suction side of which there is an apparent boundary layer separation at stalling condition because of its large impending angle. The separation flow behind the suction side of stator blade is found to create large area of low-energy flow which blocks effective flow passage area, produces more energy losses, decreases impeller torque capacity and transmission efficiency. It is found effective to suppress the boundary layer separation by separating the original single-blade stator into a primary and a secondary part. The gap between them guides high-energy flow at the pressurized side of the primary blade to the suction side of the secondary one, which helps to make boundary layer flow stable. As a result, the impeller torque capacity and torque ratio at low-speed ratio increase tremendously at the cost of little drop of maximum efficiency.
Viewing 1 to 30 of 2750