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Viewing 1 to 30 of 2806
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.
2016-04-05
Technical Paper
2016-01-1119
Prashant Jha
The Concept of Automatic Transmission is ubiquitous and ever increasing as they offer an ease of operation. Implementation of automatic Transmission in manual gear boxes however is relatively new. Based on Fuzzy Logic a Shift Schedule has been developed for Automatic Manual Transmission (AMT), to estimate various loads and resistances incurred by road Gradients and Loading conditions. A Shift Schedule has been designed in accordance with vehicle speed, road loads and throttle valve opening. This will ultimately result in an automatic gear box with improvement in shift quality and prudent Gear shift irrespective of rider competence. This Shift Schedule control method significantly reduces Gear hunting at variable gradients and at different loading conditions.
2016-04-05
Technical Paper
2016-01-1109
Okumura Naotoshi
Transmission structure and specifications ・Technology for transmission efficiency improvement ・Development of new control to improve drivability A new generation CVT with auxiliary gear box has been developed and started to be sold in the market. It has wider ratio coverage than previous generation and lower friction realized by several technologies, such as hydraulic control system improvement, oil pump loss reduction, friction reduction of ball bearing with seal , and some other technologies. Ratio shifting control and auxiliary gear box shifting control has been improved and newly developed controls are also introduced together with torque converter lock up clutch control improvement . Those new controls improved vehicle drivability and performance. In this presentation, the outline of the new generation CVT with auxiliary gear box will be explained and topics of new technologies will also be highlighted.
2016-04-05
Technical Paper
2016-01-1107
Jing Yuan
The belt clutching CVT drive has been developed for the scooter application. It utilizes the belt as a clutching mechanism instead of the traditional centrifugal clutch that is commonly employed in conjunction with the driven clutch of the drive train. By eliminating the centrifugal clutch, 48% mass reduction of the driven clutch has been achieved as well as cost saving. By placing the belt clutching directly at the engine crankshaft, fast throttle response and better vehicle acceleration/deceleration have been attained. The belt clutching mechanism demands a better performance belt to withstand the additional clutching induced wear and tear. The newly developed carbon cord belt, G ForceTM C12, meets the challenge. The common edge cord pull-out failure mode is eliminated, and the overall wear is improved. An analytical program PTWork has been developed and proven to be instrumental in integrating CVT clutch hardware with the CVT belt.
2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei WU, Xiang Chen
During the process of vehicle creeping, severe vibro-impacts of unloaded or lightly loaded gear pairs in a manual transmission may occur in the powertrain system due to some nonlinear characteristics. Multi-staged stiffness clutch damper, as a main nonlinear component, could have a great influence on powertrain system torsional vibration performance. So a mass-production passenger sedan is taken as the research subject and the nonlinear characteristics impact of multi-staged stiffness clutch damper for vehicle creeping vibration is investigated by using lumped-parameter modeling method. Firstly, a quasi-transient 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 achieved and as the input excitation to the driveline. Secondly, a 12 DOFs (Degrees of Freedom) nonlinear and branched torsional vibration model is established.
2016-04-05
Technical Paper
2016-01-1118
Yanwu Ge, Ying Huang, Gang Li, Meng Xia
Under the torque-based control architecture, the engine and AT (automatic transmission)coordinate control for upshift process is investigated. Based on the dynamics analysis, quantitative relationship between the turbine torque of HTC (hydrodynamic torque converter) and output shaft torque of AT has been obtained. Then the coordinate control strategy has been developed to realize the torque trajectory of AT output shaft. The designed control strategy is tested on a powertrain simulation model and a test bench. Through simulation, the shift time range in which the engine control strategy is effective is acquired. The experimental results show that torque response of the diesel engine with electronic unit pump can meet the requirements of coordinate control and the developed coordinate control strategy can reduce the output torque fluctuation and improve the shift quality apparently.
2016-04-05
Technical Paper
2016-01-1142
Andrew Moskalik, Aaron Hula, Daniel Barba, John Kargul
In preparation for the midterm evaluation (MTE) of the 2017-2025 light-duty GHG emissions rule, the Environmental Protection Agency (EPA) has refined and revalidated their Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) tool using newly acquired data from model year 2013-2015 engines and vehicles. ALPHA is a physics-based, forward-looking, full vehicle computer simulation capable of analyzing various vehicle types with different powertrain technologies, showing realistic vehicle behavior, and auditing of all internal energy flows in the model. As part of the validation of ALPHA, the EPA obtained model year 2014 Dodge Chargers equipped with 3.6 liter V6 engines and either a NAG1 five-speed transmission or an 845RE eight-speed transmission. Examples of each vehicle were tested on a chassis dynamometer, with eight-speed vehicles averaging 6.5% reduction in unadjusted combined city-highway CO2 emissions over five-speed vehicles.
2016-04-05
Technical Paper
2016-01-1127
Enrico Galvagno, Guido Ricardo Guercioni, Alessandro Vigliani
This paper presents a methodology for the assessment of the NVH performance of a DCT depending on some transmission design parameters, e.g. torsional backlash in the synchronizers, clutch disk moment of inertia, etc., during low vehicle speed maneuvers. Firstly, a 21-DOFs nonlinear dynamic model of a C-segment passenger car equipped with a DDCT is presented. From the torsional variables computed during simulation, the forces at the bearings that support the transmission shafts are calculated; both the axial and radial component of each bearing force are estimated through the model. It has been noted that an impact between the teeth of two engaging rotating components, e.g. gears and synchronizers, corresponds to an impulse in the simulated forces, which leads to a bearing force time-history characterized by a very rich frequency content. A broad band excitation is therefore applied to the gearbox case thus generating noise and vibration issues.
2016-04-05
Technical Paper
2016-01-1378
TAKANORI IDE, Kentaro TODA, Yasunori Futamura, Tetsuya Sakurai
Efficient method to solve large-scale eigenvalue computation in vibration is presented. NVH(Noise, Vibration and Harshness) performance is an important quality measure of the vehicle. Therefore the reduction of vibration is one of the key considerations of new automatic transmission design. In addition, accelerating product design time is another important issue. Computer Aided Engineering (CAE) is becoming a more important methodology to reduce product design time. However computational time of eigenvalue problem takes a long. We propose parallel eigenvalue computation (Sakurai-Sugiura method) for large-scale eigenvalue problems. This method has a good parallel scalability according to a hierarchical structure of the method. As a demonstrative problem, we consider large-scale eigenvalue computation of the AISIN AW FWD automatic transmission.
2016-04-05
Technical Paper
2016-01-1110
Toshinari Sano, Masashi Inoue, Fumihiro Itoigawa
In this report, for the purpose of advancing the estimation accuracy of maximum traction coefficient, we improve the temperature estimation model in the contact portion and verify it by measurement. Traction drives have been developed such as a continuously-variable transmission component for motor vehicles. The contact portion between the rolling elements mutually transmits power and always in a state in which oil film is formed. The oil film is solidified and sheared in high pressure GPa units, and also affects its own shear properties by the heat generation temperature rise. It can be said that the most important factor in estimating the traction power transmission capability is a temperature of the contact portion. The authors have already proposed the calculation method of maximum traction coefficient, in which the inside of the contact ellipse was represented by a simple combination of viscous-plastic model.
2016-04-05
Technical Paper
2016-01-0422
Robert A. Smith, Christopher Rudzinskas
“Molecular Analysis of Automotive Electrical Components Contaminated with Engine and Powertrain Performance Fluids” Robert A. Smith and Christopher R. Rudzinskas, Advanced Materials Group, Delphi Electrical/Electronic Architecture, Warren, Ohio Increased government regulations for increased fuel efficiency to combat rising fuel costs and environmental concerns has led to marked reduction in the size of cars. Automobile downsizing has reduced engine compartment volumes - decreasing separation of polymeric electrical components from fluid accesses and reservoirs and increasing the risks of spillage onto the components. The spatial separation has been reduced even further with trends toward high performance turbo-charged engines with enhanced automotive performance. Once contaminated, the polymeric component is then exposed to heating, due to engine performance, which could exacerbate fluid contamination into the interior of the part through imbibition into amorphous regions.
2016-04-05
Technical Paper
2016-01-1358
Jerry Lai, Youssef Ziada, Juhchin Yang
During the planetary gear assembly, staking is a widely-used method for affixing pinion shafts into the position. A reliable staking process not only prevents the movement of the shaft during transmission operation, but also minimizes the distortion of the assembly due to the staking process. The quality of staking operations is determined by the component designs, the process parameters, and the staking tool geometry. It would be extremely time-consuming and tedious to evaluate these factors empirically; not to mention the requirement of prototypes in the early stage of a new program. A Non-linear Finite Element methodology has been developed to simulate the complete staking process including shaft press in, staking, and after staking tool release. The critical process parameters, such as staking force, staking length, shaft and holes interference amount, etc., are then evaluated systematically.
2016-04-05
Technical Paper
2016-01-1144
Syeda Faria Mahmud, Shahjada A. Pahlovy, Masamitsu KUBOTA, Makoto Ogawa, Norio Takakura
In a gasoline vehicle, about 5-6% of the total fuel energy is wasted due to inefficiency of transmission and other parts of the driveline. This loss can be reduced by reducing the drag torque of transmission clutch. The drag torque is developed; since the friction disks and plates of clutch are always in rotating motion with fluid.This undesired drag loss has significant effect on reducing the efficiency of transmission and increasing the fuel consumption of a car. Therefore, it is important to understand the physics of this kind of flows and identify design variables and parameters that dictate the loss mechanism. The most conventional technique to suppress the drag torque is to cut grooves on the friction disk to facilitate smooth and faster discharge of the ATF. The shape of the grooves also plays a substantial role on the drag torque characteristics.
2016-04-05
Technical Paper
2016-01-1096
Chun Hui, Yang Wang
Several factors including internal factors which are related to the structure and components of transmission and external factors which are related to the running condition influence transmission efficiency collectively. This paper mainly discusses effects of different transmission running condition under different gears for transmission efficiency and deduces a methodology for simulation of efficiency. On the test rig, the mechanical transmission is experimented in different speeds, torques and work temperature, thus the corresponding data are obtained. With these experimental data, further analysis, such as relationship between torque and efficiency under the same gear and speed, is performed. Main power-loss factors including gears meshing power loss, gears churning power loss and so on also affect transmission efficiency. Considering these, this paper applies a methodology about power-loss factors to deduce the transmission efficiency.
2016-04-05
Technical Paper
2016-01-1147
Xiaofeng Yin, Han Lu, Xiaojuan Zhao, Xiaohua Wu, Yongtong Zhang
To improve the comprehensive performance of vehicles equipped with stepped automatic transmission (SAT), the optimization of gearshift schedule should take into account various performance such as power performance, fuel economy, etc. In addition, the SATs would become more acceptable if the optimized gearshift schedule could also be individualized to reflect the driver’s expectation on vehicle performance to a reasonable extent. For the purpose of ensuring the comprehensive performance and improving the individual-ability of vehicles equipped with SAT, a linear weighted method has been proposed to construct the a performance evaluation function, which applies different weights to represent driver’s expectation on performance by using these weights to multiply the normalized value of each sub-performance index.
2016-04-05
Technical Paper
2016-01-1124
Luca Castellazzi, Andrea Tonoli, Nicola Amati, Alessandro Piu, Enrico Galliera
The term driveability describes the driver's complex subjective perception of the interactions between himself and the vehicle. One of them is associated to longitudinal acceleration aspects. At the moment, a relevant contribution to the driveability process optimization is realized by means of track tests in which the considerable amount of parameters (such as stiffnesses or dampers rather than the internal combustion engine control) can be tuned in order to obtain a feasible longitudinal acceleration response. The drawback of this approach is that it is carried out at a stage when a design iteration becomes very expensive in terms of time and cost. In addition, the actual trend of downsize and supercharge the engines leads to the design and the implementation of components able to attenuate the higher vibrations that can be transmitted to the driver because of larger torque irregularities.
2016-04-05
Technical Paper
2016-01-1007
Benjamin Ellies, Charles Schenk, Paul Dekraker
As part of its technology assessment for the upcoming midterm evaluation of the 2017-2025 LD vehicle GHG emissions regulation, EPA has been benchmarking engines and transmissions to generate inputs for use in its ALPHA model, a physics-based, forward-looking, full vehicle computer simulation tool. One of the most efficient engines today, a 2.0L Mazda SkyActiv engine, is of particular interest due to its high geometric compression ratio and use of an Atkinson combustion cycle. EPA benchmarked the 2.0L SkyActiv at its National Vehicle and Fuel Emissions laboratory. EPA then incorporated ALPHA into an engine dynamometer control system so that vehicle chassis testing could be simulated with a hardware-in-the-loop (HIL) approach.
2016-04-05
Technical Paper
2016-01-1092
Gabriela Achtenova, Jiri Pakosta
In the laboratories of CTU in Prague was newly built an inertia test stand, dedicated mainly for endurance tests of the internal shift mechanisms. With regard to the instrumentation of the stand, it can be used also for determination of lost power of the not-loaded transmission. In the article will be published the values for the no-load losses measured during the different conditions (temperature, shifted speed, speed of rotation) on the automotive mechanical gearbox for the transversal disposition of the drivetrain. For the further usage of the measured values is important to determine the portion of the different sources of losses. We are mainly interested to recognise how big portion play the churning losses and losses in the sealing, while these two losses remain the same, whatever the load of the gearbox will be. The losses of bearings on input and secondary shaft were calculated with the tool available from SKF.
2016-04-05
Technical Paper
2016-01-1148
Leonard Yousif, Ivan Rot, Stephan Rinderknecht
The base model represents a drivetrain with automatic transmission including torque converter and clutch. It is based on a greybox-model approach, which refers to ordinary differential equations of motion with identified parameters. The validated drivetrain model is extended in order to reproduce the driveshaft torque during a gear shift process. Therefore the model is upgraded by a transmission model with clutches for gear shifting in order to simulate these specific drivetrain dynamics additionally. The parameters have already been determined for the basic model using a method for isolated and structured parameter identification based on measurement data of an automotive drivetrain test bench. This identification approach will also be performed to obtain the parameters of the extended model as well. The extended model will be compared with a state observer which is based on a low-order model and neglects the detailed consideration of sub-models with nonlinear characteristics.
2016-04-05
Technical Paper
2016-01-1139
Yong Liu, Biao Ma, Binjie Xu, Zhifen Miao
Currently the theoretical filtration ratio is generally used for measuring the filters for vehicle hydraulic transmission. But in actual use conditions, the filtration ratio of the filter is far less than the theoretical filtration ratio. According to the problem of how to determine the actual filtration ratio of hydraulic filters in different conditions and based on the working principle of filters, repetitive filtration ratio and repetitive contamination rate were definited, and model with dynamic filtration ratio was obtained. We simulated the contamination control model with dynamic filtration ratio, and analyzed the influence of repetitive filtration ratio and repetitive contamination rate on dynamic filtration ratio. The variation of dynamic filtration ratio was validated through a series of experiments in different condition of flow rates, pressures and temperatures.
2016-04-05
Technical Paper
2016-01-1095
Susumu Hanyu
Weight reduction and high transmission efficiency demands are getting heavier to manual transmission (MT) for vehicle driving and fuel economy performance. Also comfortable shift feeling and low gear noise level are continuously required by customer because those sensitivity performances are directly recognized by driver which can determine the transmission's merchantability. Newly developed high torque capacity MT is based on serial transmission BG6 which is adopted into a lot of customer' vehicle. This new MT is weight reduced, shift feeling and gear noise performance are highly improved that keeps strong competitiveness in the future. Concerning shift feeling, its smoothness, force balance and cross shift performance are improved and optimized. Also for low gear noise performance, it was reduced to the level which can have advantage to competitor and highly comfortable for passenger vehicle. Those improvement technologies are reported as follows.
2016-04-05
Technical Paper
2016-01-1094
Fang Liao, Weimin Gao, Yan Gu, Fei Kang, Yinan Li, Cheng Wang
Generally, the gear rattle noise prediction models are composed of the mass and stiffness elements. The proposals are about the gear inertia or backlash and the shaft inertia, stiffness, but there are many detailed designs in the same inertia, stiffness or backlash conditions. Therefore, these proposals cannot guide detailed designs. These models only investigate the rattle in the rotating degree, and ignore rattle contribution in the radical and axial directions. Those prediction models only consider one or several factors which affect the rattle noise performance. It is difficult to predict the influence of individual factor and multi-factors coupling on the gear rattle noise in a rattle simulation model.
2016-04-05
Technical Paper
2016-01-1294
Jonggyu KIM, Pyoung Beom Kim, YoungChan Lee, Sunghee Jung, Byeong-Ug Choi
This paper presents the characteristics of a 3 Cylinder CVT vehicle and a process to improve fuel economy and reduce noise and vibration. To increase the lock-up area of damper clutch for the high fuel economy and to decrease booming and vibration affected by lock-up, chassis systems of a driveline and structure resonance characteristics are studied by experiment and simulation. CVT software calibration parameters are optimized for fuel economy and NVH. With This Study, the lock-up area has been increased by 300RPM and the fuel economy has been improved by approximately 1%, while the NVH characteristic is almost same.
2016-04-05
Technical Paper
2016-01-1098
Jongsool Park
The market demands for CO2 reduction and fuel economy have led to a variety of new gear set concepts of automatic transmissions with 4 planetary gear sets and 6 shift elements in recent years. Understanding the relationship between the torque of clutch and brake and gear ratio in the design stage is very important to assess new gear set concepts and to set up the control strategy for enhancing shift quality and to reduce the heat generation of clutch and brake. In this paper, a new system approach is used to unify the relationship between torque and gear ratio during the gear shift for all multi-step planetary automatic transmissions.
2016-04-05
Technical Paper
2016-01-1115
Thomas Huth, Stefan Pischinger
The demand for lower CO2 emissions requires more than an optimization of every single component but the complete system. Therefore not only the transmission has to be optimized but also the interaction of powertrain components. For the widely spread automatic transmission the main losses are caused by the actuation system, which can be reduced with an on-demand actuation system. In this paper a new on-demand electro-mechanical actuation with validation results on a clutch test bench is presented. The electro-mechanical actuator shows simulation an increase of the efficiency by 4.1 % compared to the conventional hydraulic actuation in the NEDC (New European Driving Cycle). This increase is based on the powerless end positions of the actuator (engaged and disengaged clutch). The thermal tension and wear are compensated with a disk spring. This allows a stable control over service life.
2016-04-05
Technical Paper
2016-01-1345
Chiranth Srinivasan, Darshak Joshi, Sujan Dhar, De Ming Wang
This paper details the capability of PumpLinx® and Simerics® in simulating both Steady-State (Multiple Reference Frame) and transient, three dimensional torque converter performance and predicting the coupling point in a closed torque converter system in automatic transmission. The focuses of the simulation is in predicting the performance characteristics of the torque converters at different turbine to impeller rotating speeds (speed ratios) for 5 different torque converter designs and determine the coupling point at 90°C temperature. The computational domain includes the complex 3D design of all the impeller, turbine and reactor blades, the path ways that the oil travels between the above three components and the leakage gaps between these components. The physics captured in the simulation include the turbulence in the flow field and the rigorous treatment of the Fluid Structure Interaction (FSI) for the one-way free wheel reactor in predicting coupling point.
2016-04-05
Technical Paper
2016-01-1108
Gordon McIndoe, Joseph VanSelous, Tongxiao Liu, Jeffrey David
Multi-mode powerpath configurations with a VariGlide continuously variable planetary transmission can yield wide ratio spreads with excellent transmission system efficiencies. A simulation methodology can be used to estimate the operating efficiencies for various power path configurations.
2016-04-05
Technical Paper
2016-01-1103
Andrei Keller, Sergei Viktorovich Alyukov
In this paper we investigate power distribution mostly in off-road vehicles. It is well known, that there are different methods of power distribution in all-wheel-drive trucks. The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity, and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-to-weight ratio of a vehicle and its weight, the growth rate of velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.
2016-04-05
Technical Paper
2016-01-1061
Guiping Yue, Wenbo Niu, Jian Zhao, Dandan Kong, Yun Li, Hangsheng Hou
Gear whine noise impacts customer perception of the interior sound quality, and it has been a much discussed topic regarding the transmission NVH performance in the automotive industry. Based on multi-body dynamics, this work carries out a transmission system whine noise simulation, taking into consideration of gear macro parameter setting and micro tooth surface modification theory. Along the same line, the transmission gear macroscopic and microscopic parameters are optimized. The results show that the control of gear transmission error is an effective measure to resolve the transmission noise issue.
2016-04-05
Technical Paper
2016-01-1116
Branimir Skugor, Joško Deur, Vladimir Ivanovic
The automatic transmission gear ratios are set in order to meet vehicle speed and propulsion torque targets while ensuring good fuel economy, drivability, and driving comfort performance. Apart from determining appropriate values of transmission gear ratios (in the hardware design stage), it is also crucial to design and parameterize shift scheduling and shift control strategies. In the automotive practice, shift scheduling is commonly implemented through shift scheduling maps that are considered robust and intuitive. These maps are calibrated by highly-experienced engineers and, as such, they result in satisfactory vehicle performance. However, the achieved performance is still suboptimal, and the calibration process can be time consuming. In order to achieve optimal vehicle performance and to shorten the calibration time, it is possible to use model-based numerical optimization methods to determine optimal shift schedules for different driving scenarios.
Viewing 1 to 30 of 2806