Browse Topic: Hydromechanical transmissions

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Hydrodynamic Drives TerminologyJ641_201912 (Current)12/2/2019
Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. EXAMPLE: Two systems of blade angle designations are described. Consequently, when a blade angle is specified, the system should be designated. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.
Automatic Transmission and Transaxle Committee
Automatic Transmissions - Schematic DiagramsJ647_201911 (Current)11/19/2019
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.
Automatic Transmission and Transaxle Committee
Domestic Performance Torque Converter ManufacturingJ2440_201910 (Current)10/9/2019
The scope of this SAE Draft Technical Report is to establish dimensional standards for high-performance domestic torque converter manufacturers. Many torque converter manufacturers build converters to their own standards. Some of these standards may be outside of the specifications that define a quality performance torque converter.
Motor Vehicle Council
Automotive Transmission TerminologyJ645_201708 (Historical)8/25/2017
The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.
Automatic Transmission and Transaxle Committee
Reduction in Dynamicl of the Hydromechanical Transmission on the Wheeled Chassis2015-01-27899/29/2015
The article has represented the results of researching multiple wheeled chassis (MWC) hydromechanical transmission dynamic loading. On the basis of comparing frequencies of dynamic moment resonant fluctuations and frequencies of diesel engine indignation, the hypothesis about subharmonic resonance realization in the mechanical system having strong nonlinear elastic characteristic is offered and grounded. A method of tuning out undesirable fluctuations which form dynamic loading to take subharmonic resonant modes out of the engine rpm speed working range is developed. On the basis of the results obtained, some technical decisions are suggested which allow decreasing transmission dynamic load and a new type damper designs of different models are developed. It allows taking resonant modes out of the engine rpm speed working range, thus creating the conditions of increasing transmission elements durability.
Taratorkin, Igor, Taratorkin, Alexander, Derzhanskii, Viktor
Passenger Car and Light Truck Automatic Transmission and Automatic Transaxle Test CodeJ651_201506 (Current)6/30/2015
The extent of test conditions on the dynamometer must be sufficient to determine the efficiency characteristics corresponding to the following range of vehicle operations in all gear ratios with locked torque converters (open converter can also be done where appropriate and noted). a Efficiency versus output speed versus input torque b Torque ratio versus output speed c Input speed versus output speed d Output torque versus output speed e Parasitic loss versus input speed (spin losses) f Cooler flow g Output torque bias (front wheel drive transaxles)
Automatic Transmission and Transaxle Committee
Quasi-Continuously-Variable Transmission Provides Hydraulic Regenerative Braking for Passenger Cars, Trucks, and Buses2014-01-17174/1/2014
A hydro-mechanical transmission is described that approximates the “gearing” performance of a continuously variable transmission and incorporates all functions required for hydraulic regenerative braking. Other characteristics such as efficiency, noise, and responsiveness, match or exceed that of present day conventional automatic transmissions. Performance and physical sizing are shown for passenger vehicle, bus and truck transmissions.
Lloyd, Robert
A Dual Clutch Torque Converter for Dual Input Shaft Transmissions2013-01-02324/8/2013
This paper presents an alternative launch device for layshaft dual clutch transmissions (DCT's). The launch device incorporates a hydrodynamic torque converter, a lockup clutch with controlled slip capability and two wet multi-plate clutches to engage the input shafts of the transmission. The device is intended to overcome the deficiencies associated with using conventional dry or wet launch clutches in DCT's, such as limited torque capacity at vehicle launch, clutch thermal capacity and cooling, launch shudder, lubricant quality and requirement for interval oil changes. The alternative device enhances drive quality and performance at vehicle launch and adds the capability of controlled capacity slip to attenuate gear rattle without early downshifting. Parasitic torque loss will increase but is shown not to drastically influence fuel consumption compared to a dry clutch system, however synchronizer engagement can become a concern at cold operating temperatures. The performance of the dual clutch torque converter is assessed in a 7 speed front wheel drive DCT application and compared against the dry clutch system in the areas of launch, start/stop, driveline torsional isolation, gear rattle mitigation and fuel consumption. The dual clutch torque converter is shown to overcome the shortcomings of a dry friction launch system and deliver equivalent fuel economy performance.
Robinette, Darrell, Skrzycke, Ted
Hydrodynamic Drives TerminologyJ641_201206 (Historical)6/4/2012
Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.
Automatic Transmission and Transaxle Committee
Symbols for Hydrodynamic DrivesJ640_201107 (Current)7/8/2011
The following system of symbols is recommended for use in technical papers and engineering reports dealing with hydrodynamic drives.
Automatic Transmission and Transaxle Committee
Torque Converter Clutch Optimization: Improving Fuel Economy and Reducing Noise and Vibration2011-01-01464/12/2011
The torque converter and torque converter clutch are critical devices governing overall power transfer efficiency in automatic transmission powertrains. With calibrations becoming more aggressive to meet increasing fuel economy standards, the torque converter clutch is being applied over a wider range of driving conditions. At low engine speed and high engine torque, noise and vibration concerns originating from the driveline, powertrain or vehicle structure can supersede aggressive torque converter clutch scheduling. Understanding the torsional characteristics of the torque converter clutch and its interaction with the drivetrain can lead to a more robust design, operation in regions otherwise restricted by noise and vibration, and potential fuel economy improvement. The objective of this paper is to present a generalized integration summary for torque converter clutches (TCC) to enable aggressive apply at high engine torques and engine speeds below 1500 rpm without adversely affecting noise and vibration (N&V) performance. The focus is on optimizing existing damper technologies found in a large percentage of current production automatic transmissions. The overall goal is to demonstrate that through proper hardware selection and TCC calibration, a balance between N&V and fuel economy can be achieved. A validated lumped parameter modeling technique for optimizing torque converter clutch hardware that comprehends the complete powertrain and driveline system is used to investigate required TCC hardware. A torsional isolation metric across the powertrain is presented for comparing the performance of various damper designs. For operating points with inadequate isolation a controlled amount of slip across the torque converter clutch is required to increase isolation. An analytical methodology for minimizing the amount of slip required to satisfy noise and vibration targets and maximize fuel economy is reported. The effect of gear state, torque converter slip and power delivered to the driveline on fuel economy are also discussed based upon powertrain dynamometer measurements.
Robinette, Darrell, Grimmer, Michael, Horgan, Jeremy, Kennell, Jevon, Vykydal, Richard
A Power-Split Hybrid Hydraulic Vehicle Transmission Modeling and Comparative Analysis2010-01-201010/5/2010
Recent innovative drives in hydraulics could introduce very competitive hybrid hydraulic vehicles (HHV). These drives has been considered and analyzed only in the serial HHV architecture. The series-parallel transmission architecture, also called power-split or e-CVT is highlighted as the most popular concept for full (strong) hybrid electric vehicles (HEV). The examples are one-mode power-split in Toyota Prius and two-mode (compound) power-split in GM-Allison EVT. Ambitions to make the hybrid hydraulic power trains better and more efficient would certainly require deeper analysis of more complex power-split (series-parallel) HHV transmission structures and related optimal controls. This paper presents bond graph based mathematical model of kinematics of a one-mode and a two-mode power-split hybrid hydraulic vehicle transmissions which are based on their hybrid electrical counterpart. Such models serve as a basis for the analysis of the steady-state behavior of two representative power-split HHV transmissions. The analysis encloses the power train power flow. Related consideration of limitations and possible energy recuperation is given, too. Obtained kinematics mathematical models provide the basis for their upgrade with dynamics effects using bond-graphs, and the example is given in the paper, as well.
Petric, Josko
Automatic Transmissions - Schematic DiagramsJ647_201004 (Historical)4/23/2010
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.
Automatic Transmission and Transaxle Committee
Target Volume Based Shift Controls with High Flow PWM Solenoids2010-01-03694/12/2010
The Chrysler Ultradrive four-speed transaxle 41TE was the first production transmission to pioneer fully adaptive direct clutch-to-clutch electronic controls without overrunning clutches. "Single stage" high flow PWM solenoids have been used for transmission control since 1989 and still being used in the later-developed 545RFE and 62TE transmissions. The proposed target volume-based shift control method allows the usage of flow-based control device such as PWM solenoids to implement torque-based control strategy. Vehicle test results with this new method have shown excellent shift quality and improved system consistency.
Chen, Gang, Dourra, Hussein
Automotive Transmission TerminologyJ645_200903 (Historical)3/3/2009
The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.
Automatic Transmission and Transaxle Committee
New Generation Hydraulic-Mechanical Transmission with Lock-up Mechanisms and Automatic Start Clutch2008-32-00409/9/2008
New Generation Advanced Hydraulic-Mechanical Transmission (A-HMT) with the Lock-Up mechanism and the automatic start clutch mechanism was developed. In the lock-up mechanism, an electronic control in conjunction with transmission control was adopted using oil temperature, throttle opening, and input / output rotation ratio as parameter to reduce a rotational energy change of input and output axis caused by the volumetric efficiency of A-HMT. In the automatic start clutch, the load sensing function, damper function, and cooling function by replacing the simple hydraulic mechanism are equipped. By these solutions, the transmission efficiency has enhanced approximately 10% compared with former A-HMT, and excellent starting performance and smooth transmission performance have achieved.
Yoshida, Yoshihiro, Yakigaya, Nobuyuki, Nakamura, Kazuhiko, Takeuchi, Kazuhiro, Nakano, Kenichi, Usukura, Yasutaka
A numerical model for the simulation of Diesel/CVT power split transmission2007-24-01379/16/2007
This paper presents a steady-state numerical model of a power split hydro-mechanical input-coupled transmission for off-road vehicles. In this kind of transmissions the combustion engine is connected to a planetary and to a hydrostatic unit. Depending on vehicle speed and power request, the power is transmitted either hydrostatically or mechanically, or in both ways. The performance of the Diesel engine has been simulated in a simple manner by means of a look-up table, based on the specific fuel consumption map; a similar approach has been adopted for the efficiency of the hydrostatic units. The code is able to predict the overall efficiency of the powertrain, while highlighting the contributions of the hydrostatic path, of the mechanical path and of the engine. The results show how the code can be used both for locating the optimum operating point, as a function of the specific duty, and for analysing different configurations of the transmission.
Casoli, P., Vacca, A., Berta, G.L., Meleti, S., Vescovini, M.
Analysis of a Hybrid Multi-Mode Hydromechanical Transmission2007-01-14554/16/2007
A multi-mode hybrid hydromechanical transmission (HMT) with infinite variability is designed to meet the power transmission needs of medium duty on- and off-road vehicles. A hydraulic pump-motor assembly provides output speed and torque variability in an input coupled split power configuration. Dual planetary arrangements with two multiplate clutches allow multi-mode ratio change and combination of power from the mechanical and variable branches of the power path. Hydraulic accumulators offer hydraulic power assist during launch conditions and storage of reclaimed energy during braking events. Transmission kinematic, force and power flow analyses will be developed for the HMT and analyzed for suitability in a bus application. The resulting benefits and areas for improvement will be discussed.
Fussner, Doug, Wendel, Glenn, Wray, Chris
The Fundamental Aspects of the Structural Theory of Multispeed Transmissions Control2005-01-15984/11/2005
The first level task among the tasks of analysis and synthesis of the control systems (CS) for multispeed transmissions (MT) is the organization of speed shifts process. The method of synthesis of electrohydraulic schemes of mechatronic CS, that is based on the theory of discrete logical devices is worked out by us (see SAE Tech. Pap. Ser. 2003-01-0319). It was shown, that there is a close relation between the structures of CS and MT. Therefore it is necessary to know the properties of MT as the object of control. The analysis of such properties is the subject of this paper. It is shown that the relation between CS and MT at the level of their structures may be described quite fully with help of three basic parameters of MT kinematics schemes: the number of freedom degrees, the number of control elements (CE), the number of speeds. The concept of generalized CS and MT is introduced. This concept permits to give quantitative evaluation of their multiplicity, to formulate and to decide the series of structural tasks by using mathematical methods of combinatorial analysis and graph's theory.
Krasnevski, L.
New Technology for the Management and Distribution of Torque in Modern Automotive Drivetrains2005-01-06304/11/2005
Hydraulic, mechanical, and electro-magnetic technologies have been the primary means for torque management in today's drivetrains. Recent advances in electronic controls have provided even greater performance benefits for these base technologies. These facts coupled with an extended period of design and development for these drivetrain systems make the introduction of a new technology very challenging. However, recent developments at Borg Warner's Powertrain Technical Center have shown that a new technology, hydro-mechanical technology, may hold great promise in solving some of the fundamental problems and limitations of today's torque management technologies. This paper illustrates drivetrain applications where hydro-mechanical technology offers new and improved performance benefits for some of drivetrain's oldest problems. The opportunity to bring a new technology to the market in drivetrains also provides a new opportunity for powdered metallurgy (P/M) content in same. As a leader in P/M use in drivetrains, Borg Warner seeks to continue its commitment to P/M with this new drivetrain technology.
Kelley, William R.
Power Split Transmissions Versus Hydrostatic Multiple Motor Concepts - A Comparative Analysis2004-01-267610/26/2004
The aim of the presented study was to analyze the potentials of two different drive line concepts. The comparison is made for a simple Power Split Drive and a Hydrostatic Two-motor Transmission with a disconnectable hydromotor. The main focus is put on the achievable overall efficiency of both alternatives. The system complexity of the two compared transmissions is very different. The analysis therefore also looks towards this matter and further makes an assessment of the different control requirements.
Krauss, Alexander, Ivantysynova, Monika
The Synthesis Method of Electro-Hydraulic Schemes of Mechatronic Control Systems for Hydromechanical Transmissions2003-01-03193/3/2003
The multispeed hydromechanical transmissions (HMT) belong to the most complicated automotive components. For many years the theory and the methods of the HMT analysis and synthesis were developed. For example, the “Lever Analogy” method is known (see SAE Pub. N810102 (1981). New computer-aided methods allow synthesis HMT kinematic schemes with preset gear ratio ranges. The most important element of any modern HMT is the mechatronic control system (MCS), that practically gives to it the properties of continuously variable transmission. The base of MCS is the electro-hydraulic part, that defines its liveness and safety. Nevertheless, the analysis shows that apparently there are no generally accepted methods of their construction. In this paper the analytical method of synthesising HMT electro-hydraulic control system is proposed. It is based on the theory of analysis and synthesis of discrete logical devices which is well known in technical cybernetics.
Krasnevski, Leonid
Concepts and Development Trends for Efficiency Improvement of Hydrostatics in Mobile Applications2002-01-14223/19/2002
In mobile vehicles such as earth moving machines, agriculture machines, forest machines, industrial and mining lifters there is a demand for sophisticated performance. Since the requirements on productivity are very high for mobile machinery, high output capacity combined with high overall efficiency over a wide velocity range is therefore of great importance. A traditional solution for drive train in mobile machinery is to use a hydrodynamic transmission (torque converter) in series with a multi-speed shiftable gearbox. For heavy machines, engine power above 150 kW, torque converters have been used exclusively until a few years ago. However, the development of hydrostatic drive concepts and microprocessor control have made it possible to be competitive with converter drives. Joining pumps, motors and mechanical gears in smart concepts, so called power split transmissions, has make it possible to keep prescribed output power and velocity range without the need of sophisticated power shift gearboxes. In constant pressure hydraulic systems gas loaded accumulators can be used for energy storage. During braking and lowering of loads, the kinetic energy of the load can be stored in the accumulator and then the energy will be reused for acceleration and lifting of the load. Secondary controlled motors and hydrostatic transformers are components that can be used in conjunction with accumulators to improve the overall efficiency of hydrostatic systems. The need is also growing for technology that is capable of not only efficiently producing high-quality works, but also being environmentally friendly. In that sense, high efficient hydrostatic systems with good controllability would be extremely useful in a large quantity of outdoors industrial applications. The aim of this paper is to show how the advantage of hydrostatics can be exploited to reach high capacity, high overall efficiency and controllability required for high productivity.
Rydberg, Karl-Erik
Advanced Hydro-Mechanical Transmission with High-Durability for Small Utility Vehicles2001-01-08763/5/2001
The new automatic transmission, A-HMT (Advanced Hydro-Mechanical Transmission) has been developed for the Honda ATV (All Terrain Vehicle), which is for wide applications such as utility, recreation, etc. The A-HMT system features high performance, durability and reliability attained by improving the structures from the original hydro-mechanical automatic transmission used for the scooter called “Juno”, which Honda had produced many years ago, working on the same principle. In addition to it, by applying the electronic control system, the highly responsive driveability that suits the requirements of ATV's has been realized. The A-HMT is installed in the new 500 cm3 ATV, FOURTRAX FOREMAN RUBICON, which has been introduced in the USA market since June 2000.
Hayashi, Tsutomu, Saito, Mitsuru, Yoshida, Yoshihiro, Nanri, Takehiko
The Universal Control and Protection Hydraulic Automaton for Hydromechanical Transmissions2001-01-08793/5/2001
Modern hydromechanical transmissions are equipped with electronic-hydraulic (mechatronic) control systems having much more functional capabilities compared to classic hydraulic systems. However, automatic hydraulic systems are widely used not only as the basic transmissions' control device and a mechanical part of mechatronic systems but also as an important facility providing reliability and safety of such systems. At the same time such an application has quite a number of restrictions, especially for transmissions with a great number of gearstages. One of the main reasons is the inability to control more than 3 or 4 stages of gears while using the vehicle's speed as a control parameter. It deals with the parabolic characteristic of the output pressure of centrifugal governor used as the vehicle speed sensor. This restriction can be eliminated by using a hydraulic detector of torque converter's turbine (i.e. input shaft of gearbox) speed. The paper considers the operating principles, design and testing of such a hydraulic automaton capable of controlling converter's lock-up clutch. It may be used in hydromechanical transmissions as the system's back up and protection or as a self-sufficient hydraulic automaton.
Krasnevski, L., Vysotski, M., Boikov, V.
Hydrodynamic Drive Test CodeJ643_200005 (Historical)5/16/2000
The range of test conditions on the dynamometer shall be sufficient to determine the primary operating characteristics corresponding to the full range of vehicle operations. The characteristics to be determined are: a. Torque ratio versus speed ratio and output speed b. Input speed versus speed ratio and output speed c. Efficiency versus speed ratio and output speed d. Capacity factor versus speed ratio and output speed e. Input torque versus input speed
Automatic Transmission and Transaxle Committee
Symbols for Hydrodynamic DrivesJ640_200003 (Historical)3/10/2000
The following system of symbols is recommended for use in technical papers and engineering reports dealing with hydrodynamic drives.
Automatic Transmission and Transaxle Committee
Hydrodynamic Drives TerminologyJ641_200003 (Historical)3/10/2000
Since the torque converter and fluid coupling have become commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. Example - Two systems of blade angle designations are described. Consequently when a blade angle is specified, the system should be designated. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.
Automatic Transmission and Transaxle Committee
The Safety of Mechatronic Control Systems for Hydromechanical Transmissions1999-01-10493/1/1999
Modern vehicles have a number of safety systems, main of which are basic control systems - steering and braking systems. Requirements to these systems, defined by the vehicles design safety, are regulated by the system of the international and national standards and rules. Mechatronic control systems of the hydromechanical transmissions pertain to the “yongest” automotive systems, and questions dealing with their safety don't have yet the complete theoretical and normative base. The connection between these mechatronic systems safety and their structure is investigated in this paper. The method of the safety analysis with help of the “refusal graphs” is proposed, which permits to bring out and to eliminate the possibility of the dangerous refusals capable to create the crash situations during automobile motion.
Krasnevski, L., Vysotski, M., Boikov, V.
Simulation of a Continuously Variable Power Split Transmission1999-01-00623/1/1999
Continuously variable transmissions promise to improve the performance and drivability of vehicles. The design and implementation of continuously variable transmissions for medium or large displacement (power) engines have been hampered by the power limitations of the belts. A continuously variable transmission with a power split design (CVPST) has been developed to minimize the loading on the belt while providing for increased power transfer compared to existing designs. To aid in the design and development of this CVPST, a simulator program has been developed. The simulator can be used to optimize the CVPST and to compare with other transmissions. Finally, an optimized CVPST design is presented.
Lu, Zhijian, Thompson, Gregory J., Mucino, Victor H., Smith, James E.
Hydrostatic Drives in Heavy Mobile Machinery–New Concepts and Development Trends9819899/14/1998
The use of hydrostatic transmission as vehicle drives is primarily motivated by its large range of continuously variable speed, high maneuverability and a possibility to increase the overall efficiency. Consequently an optimally designed system can provide low fuel consumption and thereby low exhaust gas emission. Modern technology involving electro-hydraulic systems, microprocessor control and control theory makes it easier to utilize the advantage of these properties than using traditional hydro-mechanical control. The requirements on productivity are very high for mobile machinery. High output capacity and a wide velocity range are therefore of great importance. To meet these requirements an ordinary hydrostatic transmission is generally used with a mechanical gearbox connected in series. The main drawback in this concept is the high cost in using a gearbox, which can switch gear ratios without jerks and other disturbances in speed and torque transmission. By joining pumps, motors and fixed gears in smart concepts, it is possible to keep prescribed output and velocity range without the need of a multi-speed mechanical gearbox. Two-motor concept and hydro-mechanical split power transmissions are representing interesting solutions. The natural control quantities of the transmission are the output shaft speed or torque. By using microprocessor control the flexibility of the control system increases which makes it possible to adapt different control loops for different states of driving, also taking into account simultaneous use of other hydraulic equipment on the vehicle.
Rydberg, Karl-Erik
A “Back-to-Back” Comparison of Currently Available Hydromechanical Transmissions – Utilising Boeing Easy 5™ Mathematical Modelling with the Ricardo Powertrain Library9819879/14/1998
Three currently available hydromechanical transmissions have been considered, all targeted at the off-highway market. For the purposes of this paper, these are designated Types “A”, “B” and “C”. Each unit has discreet qualities and types of application, and further differences will be highlighted. To provide a reference, a conventional six speed power-shift transmission has also been included, with a down-stream range change unit, held in “Hi” range; designated type “X”. The problem Ricardo have addressed in this paper is how to compare and contrast the qualities of these units for a potential user, who may not be familiar with off-high-way applications. The example considered in this study is a mobile rough-terrain crane manufacturer, contemplating a 25 tonne machine with a 193 kW engine and an on-highway max. speed of 75 kph.
Turner, Will, Anderson, Scott
Domestic Performance Torque Converter ManufacturingJ2440_199802 (Historical)2/1/1998
The scope of this SAE Draft Technical Report is to establish dimensional standards for high-performance domestic torque converter manufacturers. Many torque converter manufacturers build converters to their own standards. Some of these standards may be outside of the specifications that define a quality performance torque converter.
Motor Vehicle Council
Transmissions-Schematic DiagramsJ647_199707 (Historical)7/1/1997
The following schematic diagrams exemplify the SAE recommended method of illustrating automotive transmission arrangements. They were developed to standardize industry practice and facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of diagrams are used: Transmission in neutral and in gear. For illustrative purposes, some typical transmissions are shown.
Automatic Transmission and Transaxle Committee
The System Identification for the Hydrostatic Drive System of Secondary Regulation Using Neural Networks96223110/1/1996
In this paper, the system identification theory and method using dynamic neural networks are presented, the multilayer feedforward networks employed, the backpropagation with adaptive learning rate algorithms proposed. Finally the comparision of network output with that of the hydrostatic drive system of secondary regulation is given, and output error, sum-squared error et al, or the results that embody the effect of system identification given sine input to it are provided.
Liu, Qinghe, Zhao, Keding, Li, Shangyi, Wu, Shenglin, Wu, Guangqiang
The Intelligent Control for the Hydrostatic Drive System of Secondary Regulation Using Neural Networks9618388/1/1996
In this paper, the intelligent control theory and method using neural networks are presented, the multilayer feedforward networks employed, the back propagation learning algorithm proposed. Finally the angular velocity control result of the hydrostatic drive system of secondary regulation with such type of control is provided. Relative studies revealed that the intelligent control for the system using neural networks can be effective.
Wu, Guangqiang, Liu, Qinghe, Zhao, Keding
Theoretical Investigation into the Natural Characteristic of Torsional Vibration of a Hydromechanical Vehicular Transmission System9617708/1/1996
In this paper the working principle of hydraulic branch of the hydromechanical transmission is introduced, dynamic characteristic analysed, its actuating medium enclosed in the working space consists that of pump, soft pipeline and motor considered to be a torsional hydraulic spring whose torsional stiffness and damping provided. The multidegrees-of-freedom of the concentrated mass-elasticity discrete mechanics model is utilized to analyze the transmission system, and the finite element method is employed to model it, the torsional natural characteristic of the system are calculated, these provide the scientific basis for structural modification of controlling the vibration and noise.
Wu, Guangqiang, Liu, Qinghe, Zhao, Keding
The Flow Field Inside an Automotive Torque Converter: Laser Velocimeter Measurements9607212/1/1996
The 3-D flow field inside an automotive torque converter was measured using laser velocimetry. For the tests, a torque converter completely machined from Plexiglas was operated at the 0.065 and 0.800 turbine/pump speed ratio, and detailed velocities were measured in 13 planes throughout the torque converter. Digital shaft encoder information was used to correlate measured velocities with the pump/turbine angular positions to generate blade-to-blade profiles, 3-D vector plots, and contour through flow plots. Results showed large flow separation regions, jet/wake flows, circulatory secondary flows, and significant flow unsteadiness in all three torque converter elements (pump, turbine, and stator). From the measured velocities, torque converter performance parameters such as mass flows, input/output torque, element incidence angles, slip factors, and vorticities were determined. Mass flows were seen to be consistent between the elements and torque results agreed well with shaft load cell measurements. Incidence angles and slip factors deviated significantly from conditions at the design point.
Brun, Klaus, Flack, Ronald D.
Some Conceptual Designs of Heavy Vehicle Continuously-Variable Transmissions9521349/1/1995
Continuously-variable transmissions are reviewed with an emphasis on heavy agricultural and construction equipment. Designs of split-torque hydromechanical transmissions are discussed. The combination of powershift and hydrostatic elements should provide comfortable, stepless shifting and the ability to allow the vehicle to operate at optimum engine and travel speeds. An integration of a continuously-variable transmission and differential steering is proposed for tracked vehicles.
Schueller, John K., Khan, Naveed
Automatic Transmissions - Schematic DiagramsJ647_199506 (Historical)6/1/1995
The following schematic diagrams exemplify the SAE recommended method of illustrating automotive transmission arrangements. They were developed to standardize industry practice and facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of diagrams are used: Transmission in neutral and in gear. For illustrative purposes, some typical transmissions are shown.
Automatic Transmission and Transaxle Committee
Dynamic Modeling and Simulation of the Ford AOD Automobile Transmission9508992/1/1995
A transmission system model for Ford Motor Company's automatic transmission (AOD) system used in the Lincoln Town Car has been developed using the free-body diagram method (Newtonian approach). This model is sophisticated enough to represent the dynamic behavior of the transmission system, yet simple enough to use as a real time computer simulation tool, and as an embedded model within a dynamic observer. The transmission system and torque converter models presented in this paper are part of a larger powertrain system model at the Powertrain Control Research Laboratory, University of Wisconsin-Madison.
Pan, Chung-Hung, Moskwa, John J.
Development of Hydromechanical Transmission (HMT) for Bulldozers9417229/1/1994
Conventional medium to large-sized bulldozers have a powertrain comprised of a manually operated powershift transmission connected in series with a torque converter. There is a growing need, however, for a power train that is more efficient and easy to operate, thereby increasing bulldozer productivity. One answer to this growing demand is the hydromechanical transmission (HMT) developed by Komatsu for medium to large-sized bulldozers. The HMT consists of a powershift transmission combined in parallel with a hydrostatic transmission (HST) featuring a pair of hydraulic units. The HMT has a continuously variable shifting ratio and achieves high efficiency and automatic shifting. Additionally, it has an electronic controller that controls the transmission ratio to maintain engine speed at the maximum power point. As a result, bulldozers with the HMT demonstrate greatly improved productivity over bulldozers with the conventional powertrain. Furthermore, automatic shifting releases the operator from shifting operation, allowing the operator to concentrate on operating the work equipment and thereby reducing operator fatigue. This paper explains the method of selecting the gear train and hydraulic unit, and provides an outline of the control method.
Mitsuya, Hiroyuki, Otani, Keiji, Ishino, Tsutomu, Maruyama, Ryouichi, Akasaka, Toshiyuki
A Hydromechanical Transmission Optimized for Automotive Application-An Update93300211/1/1993
The proprietary CVT technology introduced at the 1991 SAE International Truck & Bus Meeting & Exposition in Chicago has subsequently gone through numerous design iterations and is currently in the second generation hardware stage. Ongoing optimization of the hardware has resulted in overall system performance which meets or exceeds initial predictions, thereby assuring suitability for all automotive applications.
Folsom, Lawrence R.
On Dynamic Characteristics of Passenger Car Powertrain with Hydromechanical Transmission93291810/1/1993
In this paper, the powertrain of passenger car is supposed to be a concentrated parameter model with its inertia neglected, the transfer function of the system is deduced, the relationship of natural frequency between hydromechanical and mechanical & hydraulic system is revealed, and several measures to increase values of powertrain freqency are proposed. Finally, the computer calculated result of dynamic characteristics of the powertrain is given.
Luo, Bangjie, Wu, Guangqiang, Wu, Shurong, Luo, Lang
Theoretical Formulation For Power Losses In Torque Converters93170210/1/1993
In this study are equated the main power losses that occur in the torque converters. The mathematical model is developed through empirical methods, taking into consideration the fluid circulation movement similar to the forced vortex. All equations for the fluid flow sections inside the torque converter are derived.
Santini, Joaquim E., Weber, Hans L.
Mathematical Model to Predict the Performance Characteristics of the Torque Converters92145211/1/1992
A theoretical procedure is described to predict the performance characteristics of torque converters with three elements. The mathematical model is developed assuming that the circulation motion of the fluid is similar to a forced vortex with a linear velocity distribuition from the mean radius (Rv). Therefore, all equations are developed for the flow section of the fluid inside the torque converter. The results obtained are compared with the conventional model and with the experimental measurements.
Santini, Joaquim Emanuel, Weber, Hans Ingo
The Lotus CVT and Evolution of the Smart Transmission Concept9221069/1/1992
This paper describes the process that redirected research effort from continuously variable transmissions (CVT's) to Smart Transmissions, the electronic control of a conventional manual gearbox. Initially work was carried out on theoretical and existing CVT's, and culminated in the proposal for a system that might solve some of the practical limitations. Following further simulation work comparing the CVT against an intelligently shifted 7 speed gearbox, it was concluded that the Smart Transmission could closely match the CVT for performance and fuel consumption. This meant original targets set by using a CVT could now be met without having to develop new transmission technology. At this point research effort was changed to developing this type of electronically controlled gearbox.
Thompson, Andrew C., Lipman, John M.
Automatic and Powershift Transmissions for Trucks91248611/1/1991
This paper reviews the development of automatic and powershift transmissions for both on-highway and off-highway trucks. Firstly, it discusses the development of the current generation of powershift transmissions and some of the technological factors that have influenced them before going on to look at some of the alternative types of automatic transmissions that have either been considered in the past or that are being considered for the future.
Mizon, R., Tuck, R. M.
A Hydromechanical Transmission Optimized for Automotive Application91269811/1/1991
The application of hydromechanical continuously variable transmission technology to a wide variety of automotive applications is made feasible by a unique design approach. Analysis indicates that the basic design scales readily to accommodate power inputs of under 7.5 KW to over 750 KW. The first prototype has been targeted to compete in the mid-range truck and bus market segments with transmission input torques in the order of 850 N.m to 1300 N.m and a maximum torque multiplication of approximately 10:l. The problems of high cost, poor efficiency and excessive noise which prevented prior hydromechanical units from gaining acceptance for automotive applications have been eliminated or reduced to acceptable levels in the new design.
Folsom, Lawrence R.
Static Pressure Measurement in a Torque Converter Stater9119349/1/1991
The objective of this paper is to experimentally investigate the static pressure field in a torque converter stator. Static pressure is the most reliable and useful quantity to measure since it is based on good fundamental physics and the experimental procedure is simple. Although the automotive torque converter is one of the most complicated turbomachines, static pressure measurement in this device has not been reported in the literature. Static pressure measurements were made in a stator blade passage. The measurements were taken at 72 locations under several operating conditions. Results show that: 1) the stator pressure field is three-dimensional throughout the whole range of speed ratio conditions, 2) the pressure distribution is poor at the blade tip section, 3) the well-known one-dimensional performance model can not accurately predict the radial distribution of torque from hub to tip, and 4) a two-dimensional inviscid flow model can reasonably predict the static pressure field at the mean radial section.
By, Robert R., Lakshminarayana, Budugar
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