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Viewing 1 to 30 of 2936
2017-03-28
Technical Paper
2017-01-0157
Forrest Jehlik, Simeon Iliev, Eric Wood, Jeff Gonder
It is widely understood that cold ambient temperatures negatively impact vehicle system efficiency. This is due to increased friction (engine oil, transmission, and driveline viscous effects), cold start enrichment, heat transfer, and air density variations. Although the science of quantifying steady-state vehicle component efficiency is mature, transient component efficiency over dynamic ambient real-world conditions is less understood and quantified. This work characterizes transmission efficiency utilizing transmission heating technologies over various drive cycles and ambient conditions. Dynamometer testing over hot and cold ambient temperatures was conducted for two vehicles utilizing transmission warming technologies, and one vehicle using pads to pre-heat the transmission. For the vehicles with transmission heating technologies, tests were conducted with the systems both on and off to compare gains in efficiency.
2017-03-28
Technical Paper
2017-01-1140
Yang Xu, Yuji Fujii, Edward Dai, James McCallum, Gregory Pietron, Guang Wu, Hong Jiang
A transmission system model is developed at various complexities in order to capture the transient behaviors in drivability and fuel economy simulations. A large number of model parameters bring more degree of freedom to correlate with vehicular test data. However, in practice, it often takes extensive time and effort to tune the parameters to satisfy the model performance requirements. Among the transmission model, a hydraulic clutch actuator plays a critical role in transient shift simulations. It is particularly difficult to tune the actuator model when it is over-parameterized. Therefore, it is of great importance to develop a hydraulic actuator model that is easy to adjust while retaining sufficient complexity for replicating realistic transient behaviors. This paper describes a systematic approach for reducing the hydraulic actuator model into a piecewise 1st order representation based on piston movement.
2017-03-28
Technical Paper
2017-01-1426
Wesley D. Grimes, Thomas H. Vadnais, Gregory A. Wilcoxson
The time/distance relationship for a heavy truck accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 2016 Freightliner Cascadia truck tractor equipped with an automated manual transmission in Auto Mode. Unlike the tests in previous papers, the driver never manually shifted gears. These tests included three trailer load configurations and two different acceleration rates. Data were gathered with both a VBOX and with the Detroit Diesel Diagnostic Link (DDDL) software. Results from both data acquisition systems were compared.
2017-03-28
Technical Paper
2017-01-1631
Weizhe Qian, Henry Zhang
Double Clutch Transmission system becomes more and more popular in vehicles because of the fuel saving performance, cost efficiency and comfortable feeling during gear change. To save fuel consumption, oil pump can be used for oil pressure on demand control. Sensorless control has cost advantage because it removes the motor position sensor. This paper will introduce a technical solution for BLDC (Brushless DC) motor sensorless control for oil pump used in DCT system. To implement sensorless block commutation of BLDC motor, usually Back-emf voltage needs to be compared with a reference voltage. A `zero-crossing point’ of the Back-emf voltage can indicate the rotor position, and hence motor can be controlled without position sensor. Phase feedback pins of Infineon pre-driver device TLE9180 provide these `zero-crossing point’ information based on hardware. The outputs of phase feedback pins are connected to a module CCU6 (capture compare unit6) from 32bit micro-controller Aurix.
2017-03-28
Technical Paper
2017-01-1108
Yulong Lei, Yao Fu, Ke Liu, Li Xingzhong, Zhenjie Liu, Yin Zhang, Xuanyi Fu
Selection of gearshift point plays an important role in the field of automatic transmission technology, which directly affects the vehicle dynamic and economic performance, etc. For stepped automatic transmission, it is generally believed that improving the fuel economy while not compromising the driveability is still a challenging research problem. And the traditional calibration method based on artificial experience widely used at home and abroad suffers from many issues, such as long development cycle, high cost, and real-time fault optimization between vehicle dynamic and fuel economy. In order to designing optimal gearshift strategies for conventional passenger vehicles equipped with stepped automatic transmission, in this paper, the analysis method of vehicle power demand was studied under different environment, different driving intention and different vehicle operating conditions.
2017-03-28
Technical Paper
2017-01-1103
Sergei Aliukov, Andrei Keller, Alexander Alyukov
The inertial continuously variable transmission is a mechanical transmission which is based on the principle of inertia. This transmission has a lot of advantages, namely: compactness, minimum friction losses and high efficiency as a result of the relatively small number of rotating components, a wide range of transformation of the torque. It does not need any conventional friction clutches. This transmission protects the engine from overload when the output shaft is braked. This drive guarantees optimum conditions of work for the engine regardless of the changing of load, and smoothly changes output speed according to the load. Mostly, design of this transmission consists of a pulsed mechanism with unbalanced inertial units and two overrunning clutches. The objects of the investigation are structural dynamic analysis of the continuously variable transmission. The physical and mathematical models of this transmission are developed.
2017-03-28
Technical Paper
2017-01-1110
Muammer Yolga, Markus Bachinger
With the introduction of new regulations on emissions, fuel efficiency and driving cycles, challenges for the powertrains are significantly increasing to a new level. During the transition phase for these new targets, hybrid-electric powertrains are an unquestioned option for short and long-term solutions. Hybridization however, not only brings benefits on these challenging efficiency or emission targets, but also allows numerous new possibilities on controls of different powertrain elements as well as new approaches of design of powertrain elements. A good example is transmissions where, hybridization allows a new transmission type called Dedicated Hybrid Transmission (DHT), which enables to use novel control strategies bringing improved performance, driveability, durability and NVH behavior. This paper focuses on the novel shift strategy where friction clutches do not have to slip.
2017-03-28
Technical Paper
2017-01-1060
Sergei Aliukov, Andrei Keller, Alexander Alyukov
The inertial continuously variable transmissions are mechanical transmissions that are based on the principle of inertia. These transmissions have a lot of advantages. Usually, the design of the inertial continuously variable transmissions consists of inertia pulsed mechanism with unbalanced inertial elements and two overrunning clutches. Dynamics of the transmissions is described by systems of substantial nonlinear differential equations. In general, precise methods of solution for such equations do not exist. Therefore, in practice, approximate analytical and numerical methods must be employed. The main analytical methods employ successive approximation, a small parameter, or power series expansion. Each approach has its advantages and disadvantages. Therefore, we need to compare them in order to select the best method for dynamic study of such kind of transmissions.
2017-03-28
Technical Paper
2017-01-1596
Amar Penta, Rohit Gaidhani, Sampath Kumar Sathiaseelan, Prasad Warule
Electrical and Series Hybrid Vehicles are generally provided with single speed reduction gearbox. But to improve performance and drive range a two-speed gearbox with coordinated control of traction motor and gearshift actuator is proposed. For two speed gearbox, gearshift without clutch would increase the shifting effort. Active Synchronization is introduced for a smoother gear shift even without clutch. The shift quality is considered as a function of force and time taken. To further enhance the quality of the gearshift, the location of the synchronizer assembly in the transmission system is optimized. To validate the improvement in the quality of the gearshift, a high fidelity model of the two speed gearbox incorporating proposed location of synchronizer assembly along with active synchronization is developed. The qualitative and quantitative analysis of the results achieved is presented.
2017-03-28
Technical Paper
2017-01-1128
Yuvraj Y. Gorwade, Anand S. Damami
To ensure a robust, reliable and durable product, predicting useful life of aggregates at the concept stage is a very important aspect in the any product design. This requirement is very much necessary in today's environment, wherein the customer expectations are increasing and allow-able development time for reliable product is decreasing. Clutch is one of the important aggregate in an Automobile having Manual Transmission, which acts like a fuse in the driveline system wherein its wear & tear cannot be avoidable. The performance of Clutch is correlated with its useful life. In this paper, a unique methodology is formulated for the prediction of useful clutch life. Actual field data like warranty, type of failure, etc on a typical utility vehicle platform has been captured for over 3-4 years which have been operating on Indian roads. With the help of data analysis, beta life of clutch, for a given vehicle configuration has been calculated using statistical approach.
2017-03-28
Technical Paper
2017-01-1123
Jinyu Zhang, Yaodong Hu, Fuyuan Yang, Chao Xu
Engine torque fluctuation is a great threat to vehicle comfort and durability. Former researches tried to solve this problem by introducing active damping system, which means the motor which is directly coupled to engine shift is controlled to produce torque ripple with just the opposite phase to that of the engine. By this means, the torque fluctuation produced by the motor and the engine can be reduced. In this paper, the author attempts to propose a special used motor for HEV (Hybrid Electrical Vehicles), by changing the traditional structure of the motor which can produce ripple torque by itself. Therefore, four kinds of motors have been investigated and compared. Among which, SRM (Switched Reluctance Motor) has larger torque ripple, which means higher possibility to match with engine’s torque fluctuation while PMSM (permanent magnet synchronous motor) has relatively high efficiency and is widely used, which means lower fuel consumption for the whole system.
2017-03-28
Technical Paper
2017-01-1109
Keisuke Ota, Masami Kondo, Shuntaro Shinohara, Norihiro Tsukamoto, Seiji Masunaga, Ayumu Sagawa
To meet increasing driveability expectation of passenger cars, and stringent fuel economy regulations reducing emitted CO2; Toyota developed new 8-speed automatic transmission "UA80". "UA80" known as “Direct Shift-8AT” is first stepped automatic transmission model based on TNGA philosophy. The new Highlander and Sienna received Direct Shift-8AT. Direct Shift-8AT has an innovative control method with gear train and torque converter models, and provides enhanced driveability and fuel economy performance through high efficiency transmission technology. This paper describes details of new technology and vehicle performance.
2017-03-28
Technical Paper
2017-01-1231
Chun Tang, Natee Limsuwan, Nurani Chandrasekhar, Zhichun Ma, Jacob Krizan, Joel Hetrick, Wei Wu
Abstract: Machine three phase current driven by PWM switching inverter in PM machine drive is not ideal sinusoidal, containing different levels of harmonics. The current harmonics have important impact on the electrical machine torque ripple which could translate into transmission and vehicle level noise vibration and harshness (NVH). In this work, the current waveforms were measured from dyno test at prescribed torque and speed levels, and the electric machine torque ripple was computed with the measured current. This paper will focus on the investigation of the current harmonics behaviors and features at various torque and speed conditions, the impact on torque ripple, and the possible mitigation method to reduce torque ripple.
2017-03-28
Technical Paper
2017-01-1629
Jing Wang, John Michelini, Yan Wang, Michael H. Shelby
Time to torque (TTT) is a quantity used to measure the engine transient torque response. It is referred as the time duration from a full torque command to the time when 95% of maximum torque is achieved. In this work, we seek to control multiple engine actuators in a collaborative way such that the TTT is minimized. We pose the TTT minimization problem as an optimization problem by parameterizing each engine actuator transient trajectory as a Fourier series, followed by minimizing proper cost function with the optimization of those Fourier coefficients. This optimization problem is in general non-convex with unknown structure. To solve the problem in CAE environment, we construct an optimization framework that integrates high-fidelity GT POWER engine model and engine actuators’ Simulink model into modeFrontier computation platform. We conduct simulation study by using this optimization framework on two different turbocharged engines.
2017-03-28
Technical Paper
2017-01-1093
Yosuke Michikoshi, Daisuke Kusamoto, Hirofumi Ota, Masashi Ikemura, Noritaka Takebayashi, Ike Nobukazu, Yasuda Takashi, Inoue Ryohei
Because of environmental issues such as reducing carbon dioxide and tightening fuel economy regulations for automobiles, it has become essential to develop vehicles with superior fuel efficiency and cleaner emissions. At the same time, the demand of the basic performance characteristics such as driving performance and NVH is increasing. Toyota Motor Corporation has developed a new eight-speed automatic transaxle (UA80) which has realized these requirements at a high level, and is adopted into the new Siena and Highlander. UA80 is the first Toyota transaxle which incorporates the TNGA concept. It has high level competitiveness in wide torque range from L4 engine to V6 engine by using both optimization and standardization of main components. Additionally it has a superior installation performance by optimizing the transaxle size and arrangement and achieved a low gravity center. It contributes to vehicle’s attractiveness by improving driving performance, NVH and design.
2017-03-28
Technical Paper
2017-01-1628
Atsushi Ito, Masahiro Kawano, Shohei Fujita
In Gasoline Direct Injection (GDI) System, Various Injection types are needed to reduce polluting emission and fuel consumption. Therefore, high precision injection is required for small fuel amounts region. For the injection of small fuel amounts, the GDI solenoid injectors need to be worked in the half lift region. Although, injected fuel amount deviations in this region tend to increase by the injector needle lift deviations and the issue is to inject small fuel amounts with high precision. To reduce deviations, an attempt was made to analyze lift timing from driving waveform and adjust injected fuel amounts by ECU. In the injector opening time detection, it focused on a particular feature found on the current waveform at the time of injector needle open, and in the injector closing time detection, it focused on a particular feature found on the voltage waveform at the time of injector needle closure.
2017-03-28
Technical Paper
2017-01-1119
Fangwu Ma, Ying Zhao, Yongfeng Pu, Jiawei Wang
Gear transmission is one of the most widely used form in mechanical transmission system and plays an important role in Automobile industry. Manufacturing errors, assembly looseness, gear wear issues in gear transmission system may result in backlash of gear, noise and fatigue damage, which seriously affect the efficiency and service life of gear transmission. For the gear transmission assembled, it is of great importance to obtain the desired results monitoring the condition of gear meshing and prevent the occurrence of dangerous situations. How to determine whether there are some issues of gear tooth wear, misaligned bearing, gear eccentricity and backlash and how to define gear sets with problems and find the specific problems which already exist on gear transmission are of great value and significant to ensure the quality and design of product.
2017-03-28
Technical Paper
2017-01-1055
Baolin Yu, Zhi Fu, T. Bin Juang
The automotive industry is experiencing a profound change due to increasing pressure from environmental and energy concerns. This leads many auto makers to accelerate hybrid and electric vehicle development. Generally smaller engines utilized by hybrid and electric vehicles lend themselves to quieter operation. However, customer satisfaction could be negatively impacted by the peak whine emitted by electric motor. Unlike conventional gas vehicles, the strategy for reducing motor whine is still largely unexplored. This paper presents an analytical study on electric motor whine radiated from a hybrid vehicle transmission. The analysis includes two stages. Firstly a detailed finite element (FE) model of transmission is constructed, and case surface velocities are calculated utilizing electromagnetic force. Then a boundary element model is built for evaluating noise radiated from the transmission surface using acoustic transfer vector (ATV) method.
2017-03-28
Technical Paper
2017-01-1632
Norihiro Tsukamoto, Tomohiro Chimbe, Tomohiro Asami, Keisuke Ota, Seiji Masunaga
A new shift control system using a model-based control method for stepped automatic transmissions. Using a gear train numerical formula model, the model-based shift control system is constructed using minimum calibration parameters with feedforward and feedback controllers. It also adopts control target values for the input shaft revolution and output shaft torque, thus enabling precise control that provides the most suitable shift feeling in various driving situations and for various vehicle characteristics. Furthermore, the model-based shift control system improves robustness in terms of disturbance elements such as production tolerance, time degradation, and use environment. Toyota has adopted this model-based shift control system in its UA80/UB80 8-speed automatic transmissions for front-wheel-drive vehicles and its AGA0 10-speed automatic transmission for rear-wheel-drive vehicles. This paper describes the details of this model-based shift control system.
2017-03-28
Technical Paper
2017-01-1107
Christoph Andre Malonga Makosi, Stephan Rinderknecht, Ralf Binz, Frank Uphaus, Frank Kirschbaum
In order to offer a wide range of driving experiences to their customers, original equipment manufacturers implement different driving programs. The driver is capable of manually switching between these programs which alter drivability parameters in the engine control unit. As a result, acceleration forces and gradients are modified, changing the perceived driving experience. Nowadays, drivability is calibrated iteratively through road testing. Hence, the resulting set of parameters is strongly dependent on the individual sentiments of the test engineers. It is shown, that implementing a set of objective criteria offers a way of eliminating personal preferences and sentiment from the drivability calibration process. In combination with the expertise of the testing engineers, the desired vehicle behavior can be transferred into a transient set point sequence to design the acceleration behavior.
2017-03-28
Technical Paper
2017-01-1630
Yiu Heng Cheung, Zhijia Yang, Richard Stobart
It is well known now that a warmed up engine consumes less fuel using stopping and starting compared to idling for a certain period. Since the first stop-start system introduced in 1983, more and more vehicles have been equipped with this automatic engine control system. Recently, it was found that there is strong correlation between engine resting position and engine start time. The utilisation of the synchronization time with the prerequisite of engine stop position prior the engine start request was shown to reduce start times. Hence the position control of an engine during shutdown becomes more significant. This paper presents an experimental study of the positon control of a turbo-charged four-cylinder gasoline engine on a test bed. Various control authorities such as throttle control, alternator control and wastegate control have been investigated and compared.
2017-03-28
Technical Paper
2017-01-1637
David Cheng
Abstract This is a new design for sensor extreme long travel range detection technology especially for clutch master cylinder piston position detection and fork position detection in transmission application to replace PLCD (Permanent magnetic Linear Contactless Displacement) platform with simple manufacturing process and high accuracy. The main innovation point includes integrating a ferromagnetic concentrator into sensor module to enhance magnetic flux density at remote area of travel range and applying 3D Hall array with microcontroller for signal post process to guarantee the accuracy of sensor. SPI mode is used for communication between 3D Hall array and microcontroller while a new signal post process method with self-learning calibration is applied in microcontroller algorithm.
2017-03-28
Journal Article
2017-01-1127
Pengchuan Wang, Nikolaos Katopodes, Yuji Fujii
Wet clutch packs are widely used in today’s automatic transmission systems for gear-ratio shifting. The frictional interfaces between the clutch plates are continuously lubricated with transmission fluid for both thermal and friction management. The open clutch packs shear transmission fluid across the rotating plates, contributing to measurable energy losses. A typical multi-speed transmission includes as many as 5 clutch packs. Of those, two to three clutches are open at any time during a typical drive cycle, presenting an opportunity for fuel economy gain. However, reducing open clutch drag is very challenging, while meeting cooling requirements and shift quality targets. In practice, clutch design adjustment is performed through trial-and-error evaluation of hardware on a test bench. The use of analytical methodologies is limited for optimizing clutch design features due to the complexity of fluid-structural interactions under rotating conditions.
2017-03-28
Journal Article
2017-01-1138
Gary Stevens, Martin Murtagh, Robert Kee, Juliana Early, Roy Douglas, Robert Best
In this paper a dynamic, modular, 1-D vehicle model architecture is presented that improves modelling flexibility and can be adapted rapidly to new advanced vehicle concepts, including hybrid vehicles. Interdependencies between model sub-systems are minimized, thereby improving model flexibility in the development of new vehicle concepts and architectures. Each subsystem of the vehicle model follows a standardized signal architecture, therefore subsystems can be developed, tested and validated separately from the main model and easily re-integrated. The model uses standard dynamic equations to calculate the rotational speed of the desired driveline component within each subsystem i.e. dynamic calculations are carried out with respect to the component of interest. Sample simulations are presented for isolated and integrated components to demonstrate flexibility. Two vehicle test cases are presented.
2017-03-28
Journal Article
2017-01-1120
Kenji Tsutsumi, Yoshitaka Miura, Yusuke Kageyama, Arata Miyauchi
Abstract A CVT variator chain system is superior in transmission efficiency to a belt system because of its lower internal friction. However, a chain produces more noise than a belt due to the long pitch length of contact between the pulleys and rocker pins. This study focuses on optimization of the pitch sequence for reducing chain noise. The previous pitch sequence was suitably combined of links of different lengths to improve noise dispersibility for reducing chain noise. First, the object function was defined as the reduction of the peak level of 1st-order chain noise combined with a well-balanced the levels on the low and high frequency sides. Interior background noise consisting of road noise and wind noise have the characteristic that they increase as the frequency decreases.
2017-03-28
Journal Article
2017-01-1135
Sen Zhou, Bryan Williams
Transmission spin loss has significant influence on the vehicle fuel economy. Transmission output chain may contribute up to 10~15% of the total spin loss. However, the chain spin loss information is not well documented. An experimental study was carried out with several transmission output chains and simulated transmission environment in a testing box. The studies build the bases for the chain spin loss modeling and depicted the influences of the speed, the sprocket sizes, the oil levels, the viscosity, the temperatures and the baffle. The kriging method was employed for the parameter sensitivity study. A closed form of empirical model was developed. Good correlation was achieved.
2017-03-28
Technical Paper
2017-01-1096
Robin Temporelli, Philippe Micheau, Maxime Boisvert
Abstract Automated Manual Transmission (AMT) based on classic electrohydraulic clutch actuation gives high performances and comfort to a recreational vehicle. However, overall power consumption remains high due to the pump efficiency. In addition, the pump is often driven by the vehicle’s engine and thus is continuously working. To address this issue, a new electrified clutch based on electromechanical actuation has been designed and prototyped. In order to evaluate the effective fuel consumption reduction using this new clutch actuator, a low-cost and agile method is presented and used in this paper. Indeed, instead of integrating the clutch actuator in a real vehicle and performing expensive real emission test cycles on a road, this original method proposes to perform accurate semi-virtual emission test cycles. Moreover, the method allows to perform numerous test iterations in a short time.
2017-03-28
Technical Paper
2017-01-1095
Sankar B. Rengarajan, Jayant Sarlashkar, Peter Lobato
Abstract SAE Recommended Practice J1540 [1] specifies test procedures to map transmission efficiency and parasitic losses in a manual transmission. The procedure comprises two parts. The first compares input and output torque over a range of speed to determine efficiency. The second measures parasitic losses at zero input torque over a range of speed. As specified in J1540, efficiency of transmissions is routinely measured on a test-stand under steady torque and speed [2] [3]. While such testing is useful to compare different transmissions, it is unclear whether the “in-use” efficiency of a given transmission is the same as that measured on the stand. A vehicular transmission is usually mated to a reciprocating combustion engine producing significant torque and speed fluctuations at the crankshaft. It is thus a valid question whether the efficiency under such pulsating conditions is the same as that under steady conditions.
2017-03-28
Technical Paper
2017-01-1098
Tatsuya Imamura, Atsushi Tabata, Tooru Matsubara, Yuji Iwase, Kenta Kumazaki, Keita Imai
Abstract Lexus developed the Multi Stage Hybrid Transmission for the flagship Lexus LC500h coupe with the aim of achieving an excellent balance between fuel economy and acceleration performance. To gain these benefits, this transmission utilizes a multi-stage approach with the input split mode as an enabler for a concept of multiple high- efficiency points. In order to apply this approach to the transmission, a shift device was located immediately after a power split device. For functioning of the input split mode electrically-controlled continuously variable transmission, the power split device is connected with the motor, generator, and inverters. The optimal gear selection of the shift device to reduce the power loss in accordance with the driving state improves not only fuel economy but also heat management performance compared with the previous hybrid transmission.
2017-03-28
Journal Article
2017-01-1124
Enrico Galvagno, Pablo Gutierrez, Mauro Velardocchia, Alessandro Vigliani
Abstract This paper investigates the effect of the powertrain mounting system on the linear and nonlinear torsional dynamical behaviour of a transmission system. To this aim, two dynamic models, one with rigid mounts and the other with flexible mounts, are presented and compared: the first model considers only the torsional dynamics of transmission and driveline, while the second model includes also a 3 degrees-of-freedom powertrain block. The mechanical coupling and interaction between the powertrain block and transmission system is discussed and formulated. These models are then analyzed in terms of vibrational mode shapes, natural frequencies and Frequency Response Functions (FRFs); a sensitivity analysis of the main transmission parameters, e.g. the gear ratio, is also presented.
Viewing 1 to 30 of 2936