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Dynamic modeling and simulation of a powertrain system with a six-speed automatic transmission

Schaeffler Brasil Ltda.-Marcel T. da S. de Araujo, Murilo F. Falleiros, Gustavo dos S. Gioria
  • Technical Paper
  • 2019-36-0100
Published 2020-01-13 by SAE International in United States
The constant growth of the automotive market demands for comfort to the user and energy efficiency have caused the intensification of the industry researches and development of the automatic transmissions (AT). However, vehicles equipped with these gearboxes entails in higher fuel consumption levels than the one required by vehicles equipped with manual transmission. In the automotive industry due to the advantages offered using computer simulations, such as fast evaluation an optimization, many researchers are using virtual models for optimization of dynamic behavior of systems and fuel consumption. Aiming to study the dynamic behavior of an AT and the influence of its components on that behavior, this paper presents an AT dynamic model developed in MATLAB® / Simulink®. The AT model has three main subsystems: a torque converter model, which includes the dynamic of both the forward flow mode and the reverse flow mode; a Lepelletier gearbox model, composed by a set of three planetary gearsets in parallel, resulting in a six forward speeds gearbox; and a gear-shift schedule, which has the vehicle speed and accelerator…
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Understanding Base Oils and Lubricants for Electric Drivetrain Applications

Afton Chemical Corporation, Richmond, Virginia 23219, USA-Yungwan Kwak, Christopher Cleveland, Atanu Adhvaryu, Xinggao Fang
Afton Chemical Japan Corporation, Tokyo, Japan-Tsuneo Adachi
  • Technical Paper
  • 2019-01-2337
Published 2019-12-19 by SAE International in United States
The penetration of hybridization and electrification (HEV and EV) technology into automotive powertrain designs is an evolving trend resulting from global regulations intended to reduce transportation-related emissions of greenhouse gases and other pollutants and to improve vehicle fuel efficiency. In many HEV and EV hardware designs, drivetrain fluids have contact with the integrated electric motor (e-motor), which requires electrical and thermal properties to be considered in addition to traditional fluid properties.This paper discusses new insights gained around electrical and thermal properties of drivetrain fluids, with a specific emphasis on understanding the critical impacts of base oils (BOs). Electrical and thermal properties data as a function of temperature for a range of BOs as well as automatic transmission fluids are shared. We found that BOs and their viscosities play a critical role in cooling performance, while additives play a critical role in electrical conductivity (EC). That being said, we also have observed that additives in BOs can modify cooling performance. We will demonstrate how each component in the additive package affects EC and in some cases…
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Advanced Bench Test Methodology for Generating Wet Clutch Torque Transfer Functions for Enhanced Drivability Simulations

F.C.C. CO., LTD.-Takahiro Tsuchiya, Masatoshi Miyagawa, Shinji Nakamura, Matthew Wendel, Hiroya Miyoshi
Ford Motor Company-Hiral Haria, Yuji Fujii, Gregory M. Pietron, Anna Sun
  • Technical Paper
  • 2019-01-2340
Published 2019-12-19 by SAE International in United States
A wet clutch continues to play a critical role for step-ratio automatic transmissions and finds new utilities in hybrid and electrified propulsion systems. A torque transfer function is often employed in practice for sophisticated clutch slip controls. It provides a simple, yet practical framework to represent clutch torque as a function of actuator force. An accurate transfer function is also increasingly desired in today's vehicle design process to enable upfront assessment of clutch controls through simulations. The most common approach is based on Coulomb's linear friction model, where the coefficients are adaptively identified based on vehicle data. However, it is generally difficult to tune Coulomb's model for hydrodynamic behaviors even if the reference vehicle data are available. It also remains a challenge to produce in-vehicle clutch behaviors on a component test bench to determine realistic transfer function before prototype vehicles are built. SAE#2 test procedure is the industry standard for evaluating clutch frictional behaviors. It is a viable tool for durability assessment, but not designed to characterize hydrodynamic behaviors for clutch controls. This research focuses…
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Automatic Transmissions - Schematic Diagrams

Automatic Transmission and Transaxle Committee
  • Ground Vehicle Standard
  • J647_201911
  • Current
Published 2019-11-19 by SAE International in United States
The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.
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Simulation-Driven Model-Based Approach for the Performance and Fuel Efficiency Trade-Off Evaluation of Vehicle Powertrain

Universidade Federal de Campina Grande-Samuel Filgueira da Silva, Eisenhawer de Moura Fernandes, Wanderley Ferreira de Amorim Junior
  • Technical Paper
  • 2019-01-5085
Published 2019-11-14 by SAE International in United States
The automobile manufacturers are currently facing a double challenge. While they must meet tight vehicle emission regulations established by the authorities, they also have to achieve the current market demands, which look towards fuel efficient vehicles for city driving, but still delivering high performance for unproblematic highway cycles.The purpose of this study is to evaluate the influence of different axle ratios in the conflicting fuel economy versus acceleration performance trade-off. The article will present the modeling and simulation of a four-wheel-drive light-duty vehicle with six-speed automatic transmission subjected to three drive cycles: the FTP-72 (Federal Test Procedure) cycle, the Highway Fuel Economy Test (HWFET) cycle, and the 0-100 km/h acceleration cycle.The simulations were performed in MATLAB/Simulink® environment by using system modeling that incorporates powertrain components such as engine, transmission, torque converter, axle ratio, wheels, driveshaft, etc. The auto driver was implemented by the approximation of the commanded speed curves to the desired speed curves (driving cycles) using a controller subsystem.The vehicle model results aim to analyze the improvements generated by the optimal differential ratio in…
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Towed Vehicle Drivetrain Test Procedure Passenger Cars, Vans, and Light-Duty Trucks

Motor Vehicle Council
  • Ground Vehicle Standard
  • J1144_201910
  • Current
Published 2019-10-28 by SAE International in United States
This SAE Recommended Practice provides a means for evaluating the drivetrain of the passenger car, van, or light-duty truck being towed under a variety of road conditions. The towing equipment used is explained in SAE J1142. NOTE—For the purpose of this document, the drivetrain refers to the combination of a specific transmission (make, model, size, type), a specific differential assembly (make, model, size, type), and a specific driveline, if required.
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Fuel Efficiency Improvement in Automatic Transmissions by Lockup Slip Methodology

Mahindra & Mahindra, Ltd.-Arun Sukumar
Published 2019-10-11 by SAE International in United States
Increasing of automatic transmissions in passenger cars is based on pleasure of driving, smooth acceleration and easy operation makes the customer satisfaction. Challenges beyond 2020 is BS VI emission norms in India - a very tough goals on CO2& NOx reduction in Gasoline & Diesel vehicles. But its setback in lower fuel economy.To support & enhance fuel economy in Automatic transmissions as part of drivetrain technologies, this article discusses about the power losses in torque converters and experiments on the actual Automatic transmission (AT) vehicle on-road to understand the real city driving behavior in the aspects of gear utilization & gas pedal utilization throughout the entire traffic conditions. With that data research, slip area and slipping conditions is determined & clutch slip control is enabled at area in torque converter by ensuring that NVH parameters are not affected.The addition of the Lock-up Slip system add value in terms of “Joy of Driving” by providing a 2-3% improvement in fuel economy over the previous one.
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Rectangular Cross Section Polymeric Sealing Rings

Automatic Transmission and Transaxle Committee
  • Ground Vehicle Standard
  • J2310_201910
  • Current
Published 2019-10-09 by SAE International in United States
The purpose of this SAE Recommended Practice is to establish guidelines for the automatic transmission and hydraulic systems engineer to design rectangular cross section seals for rotating and static grooved shaft applications. Also included are property comparisons of polymeric materials suitable for these applications. Historically, material covered in this document is not intended to include aluminum contact applications.
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Innovative Dedicated Hybrid Transmission Concepts in the Next Generation of Hybrid Powertrains

SAE International Journal of Alternative Powertrains

Technische Universität Carolo-Wilhelmina zu Braunschweig, Germany-Haijun Chen, Lin Li, Andreas Lange, Ferit Küçükay
  • Journal Article
  • 08-08-01-0005
Published 2019-09-20 by SAE International in United States
Due to the advantages of hybrid vehicles in comparison with pure electric vehicles, Hybrid Electric Vehicle (HEV)/Plug-in HEV (PHEV) no undoubtedly becomes the reasonable and practical solution in the development of vehicle electrification at the moment. Meanwhile, Dedicated Hybrid Transmission (DHT), as the especially designed hybrid transmission for HEV/PHEV, represents the development direction of hybrid vehicles. But in the market, the well-known DHT concepts are all protected by patents by large Original Equipment Manufacturers (OEMs). How to break the patents and more importantly develop the innovative DHT concepts in the next generation is of vital importance in the development of HEV/PHEV. In this article, firstly, the features and comparisons of different well-known DHT concepts are discussed and analyzed. The mechanical and electrical complexity are introduced to essentially analyze the advantage and disadvantage of different kinds of DHT concepts. Based on the analysis, the possibilities of different DHT concepts in the next generation are further analyzed and demonstrated. The innovative DHT are derived from the analysis. In comparison with DHT in the market, the innovative DHT…
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Testing Methods and Signal Processing Strategies for Automatic Transmission Transient Multiplexed Pressure Data

Ford Motor Company-Steve Frait, Ram Sudarsan Devendran
Michigan Technological University-Mark Woodland, Jason Blough, Darrell Robinette, Carl Anderson
Published 2019-06-05 by SAE International in United States
Transmissions have multiple transient events that occur from gear shifting to torque converter clutch application. These transients can be difficult to capture and observe. A six speed front wheeled drive transmission was instrumented with pressure transducers to measure clutches and the torque converter. Due to size restrictions internal to the torque converter the data had to be multiplexed across three different transmitters. A method to capture a transient event through the use of multiplexed data was developed to create a data set with the transient event occurring on each channel. Once testing is completed, the data has to be split into individual channels and synced with the operational data. The data then can be used in both time and frequency domain analysis. It is important to understand that the data is not continuous and must be taken into consideration when post processing it for further results.
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