Browse Topic: Friction clutches

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Slip energy evaluation for a conventional friction clutch2021-26-048009/22/2021
The importance of clutch in a vehicle’s performance is not new to the automotive, commercial or agricultural sectors. So is the importance of the clutch life when it comes to the durability of a vehicle. In process of making the machines more and more efficient, one can observe a steady reduction in the overall mass of the vehicle and the parts in it. While the parts were heavier, and the friction lining surfaces were more than adequate, the life of clutch has been the best. But with reduction of the overall masses, the energy has lesser amount of sink to dissipate and is being liberated in the form of heat, rising the overall temperatures. This leads to an early wear or even a burn in the clutch. In such scenario, it is necessary to estimate accurately the energy dissipation through a defined cycle to understand the clutch performance. Although different methods exist to evaluate energy, most cases include obtaining a high amount of sophisticated data. This paper discusses a simpler
Alavilli, Satya Pavan, KADHAR MAIDEEN, SALIM MALIK
Development of GM Allison 10-Speed Heavy Duty Transmission2020-01-043804/14/2020
This paper describes the development of the GM Allison 10-Speed Heavy Duty (HD) Transmission. The trend of increased towing capacity and engine horsepower in the automotive heavy-duty truck segment has been steadily climbing for the past 10 years. The development of 10-Speed HD Transmission is designed to be best in class in for towing performance in the 2500/3500 series segment while optimizing fuel economy. The 10-Speed HD Transmission also gives the customers the option to order an integrated power take-off (PTO) unit that benefits downstream installation of utility accessories such as hydraulic pumps, generators, etc.
Lee, Chi Teck, Ames, David, Caldwell, Brett, Knoth, Matthew, Reinhart, Timothy, Kelly, Jeffrey, Kannan, Rajesh, Tanasi, German
Unpowered, Lightweight Ankle ExoskeletonTBMG-3571712/01/2019
A lightweight, low-profile, inexpensive ankle exoskeleton could be widely used among elderly people, those with impaired lower-leg muscle strength, and workers whose jobs require substantial walking or running.
Development of a Low Loss Clutch for CVT Reverse Function2019-01-077404/02/2019
Continuously variable transmissions (CVT) provide superior fuel economy by enabling internal combustion engines to operate at their “sweet spots”. However, there is still potential to improve CVT system’s mechanical efficiency, and further enhance vehicle-level fuel economy. In the past, extensive research work has focused on the core continuously variator unit (CVU) that includes pulleys and a belt or chain. Another thread of research has centered on optimization of CVT clamping force control to reduce hydraulic system loss. Nonetheless, to the best of our knowledge, very little research has looked into the planetary gear sets and clutches that enable the CVT system to switch between forward, neutral and reverse gears. The state-of-the-art reverse clutch usually consists of multiple friction and steel plates, and is normally open during all forward driving maneuvers. The relative speed between friction and steel plates is identical to turbine speed, which generate spin loss. We
Duan, Chengwu, Lee, Chunhao, Yao, Jian, Samie, Farzad, Huang, Ying
Modeling, Control, and Adaptation for Shift Quality Control of Automatic Transmissions2019-01-112904/02/2019
The parameters determining shift quality control in automatic transmissions are determined as part of the calibration of the transmission control. The resulting control system typically has three components: feedforward control, where the control output is determined before a gearshift; feedback control, where the control output is determined during the gearshift based on sensed feedback; and learning control (adaptation), where the feedforward or feedback controller parameters are modified after the current gearshift has ended and before the next similar gearshift begins. Gearshifts involving the same ratio change are referred to here as similar gearshifts, though such gearshifts may involve differences in other variables such as vehicle speed or engine torque. In most automatic transmissions, gearshifts are controlled by hydraulic clutches, and operating conditions for these clutches may vary widely, requiring a dedicated transmission controller involving significant calibration
Mishra, Kirti Deo, Cardwell, Gilbert, Srinivasan, Krishnaswamy
Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and ChartingJ2188_201807 (Current)07/25/2018
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B). Some modern vehicles
Truck and Bus Powertrain Committee
Structural Analysis Based Sensor Placement for Diagnosis of Clutch Faults in Automatic Transmissions2018-01-135704/03/2018
This paper describes a systematic approach to identify the best sensor combination by performing sensor placement analysis to detect and isolate clutch stuck-off faults in Automatic Transmissions (AT) based on structural analysis. When an engaged clutch in the AT loses pressure during operation, it is classified as a clutch stuck-off fault. AT can enter in neutral state because of these faults; causing loss of power at wheels. Identifying the sensors to detect and isolate these faults is important in the early stage of the AT development. A universal approach to develop a structural model of an AT is presented based on the kinematic relationships of the planetary gear set elements. Sensor placement analysis is then performed to determine the sensor locations to detect and isolate the clutch stuck-off faults using speed sensors and clutch pressure sensors. The proposed approach is then applied to a 10-Speed AT to demonstrate its effectiveness. A simulator is developed to qualitatively
Deosthale, Eeshan Vijay, Ahmed, Qadeer, Arasu, Mukilan, Rizzoni, Giorgio, Mohammed, Majed, Hathaway, Richard
Performance Optimization of Compressor Rotor Clutch Sub-assembly Using Electro- Magnetic Analysis2018-01-048404/03/2018
Rotor Clutch sub-assembly is one of the very important sub-assemblies (S/A) of an automotive compressor as it delivers the required torque/power to run the compressor. It mainly consists of rotor and bearing, stator, hub and armature. Rotor is rotated by engine pulley through belt drive system, while stator housing has got number of coils winded around stator slot. The hub sub-assembly is attached to the compressor shaft via spline arrangement and bolted across. When direct current (DC) is supplied to the terminal of the rotor, an electromagnetic field is generated which causes to attract the hub part towards rotor. Once the hub and rotor gets engaged each other, torque is transmitted to the compressor shaft which then helps to complete the suction and compression of refrigerant gas and thus making the vapor cycle run to produce adequate cooling in the air-conditioning (AC) system. Hence it is most important to ensure adequate and even distribution of electromagnetic field which is
Meena, Avadhesh, Sen, Somnath
Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis2018-01-040404/03/2018
During every clutch engagement energy is dissipated in clutch assembly because of relative slippage of clutch disc w.r.t. flywheel and pressure plate. Energy dissipated in clutch is governed by many design parameters like driveline configuration of the vehicle vis-a-vis vehicle mass, and operational parameters like road conditions, traffic conditions. Clutch burning failure, which is the major failure mode of clutch assembly, is governed by energy dissipation phenomenon during clutch engagement. Clutch undergoes different duty cycles during usage in city traffic, highways or hilly regions during its lifetime. A test schedule was derived using energy dissipated during every clutch engagement event as a base and using road load data collected on the vehicle. Road load data was collected in different road mix conditions comprised of city traffic, highway, hilly region, rough road for few hundred kilometers. Using this data clutch energy was calculated in all the clutch engagement events
Mohire, Sujit, Uttamani, Rahul, Tendulkar, Vishveshvar, Katarki, Shrirang, Patil, Shahaji
Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis2018-01-038904/03/2018
During every clutch engagement energy is dissipated in clutch assembly because of relative slippage of clutch disc w.r.t. flywheel and pressure plate. Energy dissipated in clutch is governed by many design parameters like driveline configuration of the vehicle vis-a-vis vehicle mass, and operational parameters like road conditions, traffic conditions. Clutch burning failure, which is the major failure mode of clutch assembly, is governed by energy dissipation phenomenon during clutch engagement. Clutch undergoes different duty cycles during usage in city traffic, highways or hilly regions during its lifetime. A test schedule was derived using energy dissipated during every clutch engagement event as a base and using road load data collected on the vehicle. Road load data was collected in different road mix conditions comprised of city traffic, highway, hilly region, rough road for few hundred kilometers. Using this data clutch energy was calculated in all the clutch engagement events
Mohire, Sujit, Chatterjee, Soumik, Bhandari, Kiran Kamlakar
Inertial Continuously Variable Transmissions and Ways to Improve Their Performance2018-01-105904/03/2018
The inertial continuously variable transmissions are transmissions of mechanical type. They have a number of advantages in comparison with other types of transmissions. For example, they have a big value of the coefficient of efficiency, since the principle of their action does not imply the need to convert energy from one type to another one. These transmissions have a compact design, a wide range of torque transformation. They can operate in direct mode, smoothing the torsional vibrations in the system. At the moment when the output shaft is stopped, the input transmission shaft continues to rotate, that prevents the engine from overloading. There are other advantages. But despite these advantages, the inertial transmissions are not widely used in the automotive industry. The main reason for this is the inadequate durability of the freewheel mechanisms involved in the designs of the inertial transmissions. The paper considers some ways to improve the efficiency and durability of the
Aliukov, Sergei, Keller, Andrei, Alyukov, Alexander
GKN readies new 2-speed e-axle for 202017AUTP11_1111/01/2017
Driveline-enhancement technology is hot these days, with Tier 1s rolling out new axle-disconnect, electric axle and light-weighting innovations in rapid cadence. In the vanguard of this trend is GKN Driveline, whose masterpiece Twinster dual-clutch differential imparted the 2016 Ford Focus RS and Range Rover Evoque dynamic torque vectoring functions across the entire speed range. That was followed by the company's eTwinster, bringing e-axle technologies pioneered in the Volvo XC90 T8 and other hybrids. Now comes eTwinsterX, which leverages those learnings and integrates a compact 2-speed transmission into a unit aimed at broad vehicle applications-from city cars to plug-in SUVs, high-performance hybrids and EVs and the upcoming wave of electrified light trucks in North America. The system is engineered for front-drive, rear-drive and all-wheel drive configurations and is claimed to be the first e-axle that is fully off-road capable. It can incorporate electric motors from 80 to 120 kW
Brooke, Lindsay, Adcock, Ian
Electronic Bi-Directional Shift Control Design and Calibration for Farm Vehicle2017-01-220510/08/2017
Agricultural tractors are often subjected to various applications like front end loading work, cultivation work, where frequent forward and reverse gears are needed. Most of Indian agricultural tractors are equipped with mechanical transmission system which demands repeated clutching and de-clutching operation for such applications resulting in increased operator fatigue and lesser productivity. Also need of electronics in Indian agricultural industry for better farm mechanization is growing high. This research work depicts development of electronic bi-directional shifting (power shuttle) control design and calibration for farm vehicle fitted with wet clutch transmission. This research also reduces operator fatigue via frequent directional shift through electronic transmission. The control system is designed without any electronic interfacing with engine and also provides clutch-less gear shifting and auto-launch which offers ease to drive even for novice driver. The power shuttle
M A, Velmurugan, Rajagopal, MahendraMohan
Road-efficient mud machine17AUTP04_0504/01/2017
Jeep's all-new 2017 Compass gets its go-anywhere guts from GKN's AWD system. Replacing the decade-old Jeep Compass is the new-for-2017 Compass, FCA's (and Jeep's) first truly global vehicle program. Styled to resemble a slightly scaled-down Grand Cherokee, the new C-segment SUV is being produced in four plants (Mexico, China, India and Brazil) and offered in 17 powertrain combinations that include diesels and 6-speed manual gearboxes. The U.S. gets the manual ‘box but not the diesel. The new Compass is based on a stretched version of FCA's so-called “small-wide 4×4” vehicle architecture that also underpins the smaller Jeep Renegade. That platform is designed primarily as front-wheel-drive and accommodates nicely the axle-disconnect all-wheel-drive system supplied by GKN (see sidebar). As a “4.4-meter” car designed to fit European and other global parking spaces, the Jeep's overall length is 173 in (4394 mm), riding on a 103.8 in (2636 mm) wheelbase.
Brooke, Lindsay
Development and Challenges of Electrically Selectable One-Way Clutches2017-01-113303/28/2017
This paper discusses new developments in the field of one-way clutches (OWC). These recent developments involve “Selectable OWC (SOWC)” actuating both hydraulically as well as electrically. The primary focus of this paper is a low-current consuming Electrical SOWC (eSOWC) used in hybrid transmission being designed and developed at Ford Motor Company. Other SOWCs currently being utilized across different applications at Ford are also discussed. Clutching devices represent significant cost, weight, size and drag-loss in automatic transmissions. However, implementation of SOWCs offers the potential to reduce transmission cost, size, weight, and spin loss; eSOWCs may also improve shift quality, reduce shift times, improve shift consistency and reduce OWC-related NVH. In Hybrid applications the electric motor(s) and SOWC create a system that is analogous to a manual transmission synchronizer. Similarly, in automatic transmissions SOWC are analogous to pump-solenoid-valve-friction-clutch
Bird, Norman J., Bindra, Raunak, Klaser, Jacob
Bond Graph Based Approach for Modeling of Automatic Transmission Dynamics2017-01-114303/28/2017
This paper describes a method for modeling the dynamics of planetary automatic transmissions by using bond graphs. Bond graph models for the most relevant planetary gear sets (single, double and stepped pinion and Ravigneaux) are summarized and used as building blocks to construct the "device-mapping" bond graphs of complete planetary transmissions. Examples used include the legendary Ford Model T transmission and state-of-the-art six- and ten-speed transmissions. A systematic procedure of deriving mathematical models based on the constructed bond graph models is described which can be applied to any clutch application combination. It is illustrated how device-mapping bond graph models can be converted into conceptual torque-path bond graphs for better insight on the analysis of transmission shift events. Lastly, the effect of system rotational inertias on shift dynamics is discussed for practical concerns.
Ivanovic, Vladimir, Tseng, H. Eric
Modeling of Dynamic Processes for Inertial Continuously Variable Transmissions2017-01-106003/28/2017
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. In this paper a comparative analysis of approximate methods of solving of differential equations for the inertial
Aliukov, Sergei, Keller, Andrei, Alyukov, Alexander
Novel Shift Control without Clutch Slip in Hybrid Transmissions2017-01-111003/28/2017
With the introduction of new regulations on emissions, fuel efficiency, driving cycles, etc. challenges for the powertrains are significantly increasing. In order to fulfil these regulations, hybrid-electric powertrains are an unquestioned option for short and long-term solutions. Hybridization however, is not only fulfilling these challenging efficiency or emission targets, but also allows numerous new possibilities on control strategies of different powertrain elements as well as new approaches of designing them. 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. The strategy introduces a novel shifting control using the integrated electric motor and special power flow of the dedicated hybrid
Yolga, Muammer, Bachinger, Markus
Analysis of Methods for Solution of Differential Equations of Motion of Inertial Continuously Variable Transmissions2017-01-110503/28/2017
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. In this paper a comparative analysis of approximate methods of solving of differential equations for the inertial
Aliukov, Sergei, Alyukov, Alexander
Estimation of the Clutch Characteristic Map for an Automated Wet Friction Clutch Transmission2016-01-111304/05/2016
Higher demands on comfort and efficiency require a continuous improvement of the shift process. During the launch and shift process the clutch control is used to get a smooth and efficient behavior. In this short time of acting the shifting behavior can be rated. Many control concepts use a clutch characteristic to calculate the actuator signal based on the clutch torque. Therefore, a high quality of this characteristic is necessary. Because of the dynamic process during clutch engagement the clutch characteristic needs further information to reach a high accuracy for the control algorithm. In this paper an existing clutch torque characteristic is extended to a characteristic map where the clutch torque becomes a function of the current actuator signal of the clutch and the clutch slip. The extension of the torque characteristic describes the slip based dependencies, e.g. the friction coefficient. The model of the characteristic map consists of the multiplication of two separate
Arndt, Thorsten, Tarasow, Alex, Bohn, Christian, Wachsmuth, Guido, Serway, Roland
Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and ChartingJ2188_201510 (Historical)10/21/2015
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B). Some modern vehicles
Truck and Bus Powertrain Committee
Prospects for Future Non-Manual Transmissions Developments for Vehicle Applications in Brazil2015-36-034809/22/2015
The purpose of this paper is to present the origins and the technology of the different types of non-manual transmissions systems currently available and the wide potential to incorporate such technologies to the vehicles made in Brazil. The Brazilian market is experiencing a huge increase in automated and automatic transmissions vehicles share, and the OEMs are adopting different strategies to offer competitive products with affordable prices to enter in this segment. Many different alternatives are available, and there is no obvious winner. This paper will describe the concepts, the architecture and the operations of such systems and point out the pros and cons of each one.
Fornari, Rafael V., Yamada, Decio, Suzuki, Alexandre
A New Control Scheme for Automated Manual Transmission with Electromagnetic Powder Clutch2015-24-254709/06/2015
This study aims to provide modeling and control approaches for automated manual passenger and commercial vehicle transmissions in order to improve the overall disengagement-gear shifting-engagement performance using electromagnetic powder clutch (EMPC). The rationale behind selecting this clutch is its rapid behavior. During the modeling procedure of the EMPC, the analogy between this type of clutches and dry plate friction clutches has been exploited and a simple control method is proposed. The study also includes modeling method for gear shifting and selecting mechanisms of the automated manual transmission gearbox as well as development and implementation of controllers which is designed for these mechanisms. Automated manual transmission gearbox is utilized due to its combination of ease of construction and ability for electronic automation.
Ergenc, Ali Fuat, Ergenc, Alp, Erdogan, Caner, Dumanli, Alper
Design of an Eddy Current Torque Bypass Clutch for Seamless Automated Manual Transmissions of Electric and Hybrid Vehicles2015-01-914307/01/2015
This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside Automated Manual Transmissions (AMTs) to perform seamless gear upshifts. Electric vehicles (EVs) with a single-ratio gearbox may provide high levels of smoothness, but using a multi-speed gearbox provides significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. AMTs can provide smooth shifts without torque interruption when coupled to a normally-open torque bypass clutch. However, conventional dry friction clutches are not best suited for such torque bypass due to wear and controllability concerns, while wet clutches would decrease powertrain efficiency due to viscous losses. An eddy current clutch would be highly controllable, simple to manufacture, low-cost, robust, and do not wear compared to friction clutches. The potential of eddy current clutches is assessed from a representative case study consisting of a ∼190
Pouliot, Gabriel, Lacerte, Marc-Olivier, Plante, Jean-Sebastien, Micheau, Philippe
Estimation of Wet Clutch Friction Parameters in Automotive Transmissions2015-01-114604/14/2015
In this paper, a new algorithm for the off-line estimation of wet clutch friction parameters is proposed for automotive transmissions, motivated by the usefulness of such an algorithm for diagnosing the condition of the clutch and transmission fluid in service. We assume that clutch pressure is measured, which is the case in dual clutch transmissions (DCT). The estimation algorithm uses measured rotational speeds and estimated accelerations at the input and output sides of a clutch, measured clutch pressures, and a simplified dynamic model of clutch friction to estimate the viscous and contact components of clutch friction torque. Coefficient of friction data is generated using the contact friction torque. A Stribeck friction model is fit to the data, and parameters in the model are then calculated by applying linear least squares estimation. The proposed estimation algorithm is tested using the simulation of a powertrain utilizing a DCT, where the clutch friction model incorporates a
Barr, Matthew, Srinivasan, Krishnaswamy
A Three Dimensional Finite Element Analysis for Grooved Friction Clutches2015-01-068804/14/2015
This paper presents three-dimensional thermal model, performed transient thermal analysis for the grooved dry friction clutches. A finite element technique has been used to study the effect of radial and /or circumferential grooves (classic models) on the temperature distribution for dry friction clutch during a single engagement. The friction clutch has been discretised using 20-noded brick elements. The effect of the groove area ratio (G.R=groove area / total contact area), number of grooves and their location are investigated. Furthermore, new groove shapes have been suggested, e.g., curved groove. The response of the new suggested groove has been compared to the already existing shapes. The commercial ANSYS13 has been used to perform the numerical computations in this paper.
Abd Al-Sahb, Wassan, Abdullah, Oday Ibraheem
Dry Dual Clutch Transmission (DCT) Thermal Model2015-01-114404/14/2015
Dual Clutch Transmissions (DCT) for passenger cars are being developed by OEMs and suppliers. The driving force is the improvement in fuel economy available from manual transmissions together with the comfort of automatic transmissions. A dry clutch system (dDCT) is currently the subject of research, development, and production implementation. One of the key issues in the development of a dDCT is clutch durability. In dry clutches with current linings, above a critical temperature, the friction system starts to suffer permanent damage. In addition, the clutch friction characteristics are a function of the clutch interface temperature. Because a reliable, low-cost temperature sensor is not available for this application, the clutch control engineers rely on a good thermal model to estimate the temperature of the clutches. A thermal model was developed for dry dual clutch transmissions to predict operating temperature of both pressure and center plates during all maneuvers. The model is
Hebbale, Kumaraswamy, Samie, Farzad, Kish, Jonathan
Normally-Engaged Dual-Piston Clutch for Engine Stop-Start Application2015-01-114104/14/2015
For the conventional 6 speed automatic transmission with engine stop-start powertrain, an electrically-driven auxiliary pump is implemented to maintain the transmission line pressure as required to lock-up the CB1234 clutch during engine auto-stop conditions. Upon releasing the brake pedal, the transmission engages into first gear with the objective to accelerate the vehicle in a responsive manner. In this study, a novel normally-engaged dual-piston clutch concept is designed to keep the CB1234 clutch locked-up during engine auto-stop conditions with the intention to eliminate the auxiliary pump without compromising vehicle performance. This dual piston clutch concept requires a relatively low line pressure to release the normally-engaged clutch when needed, thus, minimizing the hydraulic pumping work. To explore the functionality of this concept under a wide-open-throttle (WOT) auto-start transition, modeling and simulation of the normally-engaged dual-piston clutch is completed. A
Duan, Chengwu, Samie, Farzad, Hebbale, Kumaraswamy, Li, Dongxu, Lee, Chunhao
A Low Cost System for Active Gear Shift and Clutch Control2015-01-022804/14/2015
The objective of this study is to demonstrate the design and construction of an innovative active gear-shift and clutch for racecars, applied to a Formula Student car, based on the use of DC gear-motors. Racecars require extremely quick gear-shifts and every system to be as light as possible. The proposed solution is designed to reduce energy consumption, weight and improve gear-shift precision compared to traditionally employed electro-hydraulic solutions, although maintaining state of the art performances. The proposed gear motor actuation satisfies all the above objectives: energy can be saved by removing the need for power when clutch is not pulled, thus improving efficiency; by substituting the entire electro-hydraulic-systems, that accounts for approx. 5% of the overall car weight (10kg); a significant weight reduction is achieved (weight is reduced to 2kg); a fine actuation force modulation, in order to properly shift to neutral, can easily obtained with an DC electric motor
Braghin, Francesco, Salis, Francesco
The Performance Study of Air-Friction Reduction System for Hydraulic Retarder2014-01-228309/30/2014
The hydraulic retarder, which is an auxiliary brake device for enhancing traffic safety, has been widely used in kinds of heavy commercial vehicles. When the vehicle equipped with the retarder is traveling in non-braking state, the transmission loss would be caused because of the stirring air between working wheels of the rotor and the stator no matter if the retarder connects in parallel or in series with the transmission [1]. This paper introduces an elaborate hydraulic retarder air-friction reduction system (AFRS) which consists of a vacuum generating module and pneumatic control module. AFRS works to reduce the air friction by decreasing the gas density between working wheels when the retarder is in non-braking state. The pneumatic control model of hydraulic retarder is built first. Then various driving conditions are considered to verify the performance of the AFRS. The stability of the AFRS is analyzed based on the complete driveline model. And the vacuum power of AFRS and the
Wang, Can, Tan, Gangfeng, Yang, Bo, Chen, Ming, Wei, Fudong, Ni, Yabei
New Gear Locking Design in Synchromesh Gearbox Which Reduces Gear Shift Effort2014-01-232809/30/2014
This paper introduces a new design for the synchromesh gear boxes, which serves dual purpose of economizing the production cost and time of the gears manufacturing and enhancing the shift experience by reducing the shift effort. This is achieved by making changes in the “Entry chamfers” which are the angles placed on the shift sleeve and gear dog teeth, and the “Back Taper Angle” also placed on the shift sleeve and gear dog teeth. In the new design the “Entry chamfer angles” is reduced from 120° (in the existing design) to 90° and is made “Un-symmetric” from “Symmetric”. This help in reducing the shift effort, hence enhancing the shift experience by making it smooth. Another change is the “Back Taper Angle”, which is eliminated from the sleeve and the gear dog teeth and is repositioned on the hub, keeping all other important design parameters like strut / insert design, gear cone angle, gear cone finish, number of cones, cone friction material the same. The new design ensures that the
Singh, Jagjeet, Singh, Gagandeep
Analytical Study of a Dog Clutch in Automatic Transmission Application2014-01-177504/01/2014
A dog clutch, if successfully implemented in an automatic transmission, provides better packaging and the potential for improved fuel economy. The technical requirements for this concept are examined through modeling and simulation. As a first step, a physics-based component level model is developed that provides an understanding of the basic contact and impact dynamics. The model is compared to a built-in AMESim block to establish confidence. This component level model is then integrated into a powertrain system model within the AMESim environment. As a test bed, the powertrain model is exercised to simulate a friction plate to dog clutch shift in a 6-speed automatic transmission. The analysis helps to define the slip speed target at the onset of the dog clutch engagement while ensuring shift requirements are met. Finally, the model is validated by comparing the simulated results with measured dynamometer data.
Duan, Chengwu
On the Question of External Characteristic of the Inertial Continuously Variable Transmission2014-01-173304/01/2014
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 one-way clutches. The pulsed mechanism is well developed and possesses high reliability. However, the one-way clutches are the most unreliable parts of the transmission and restrain wide use of the transmission. In this paper a new design of the inertial
Aliukov, Sergei, Gorshenin, Vladimir
Design Optimization of the Rigid Drive Disc of Clutch Using Finite Element Method2014-01-080004/01/2014
A friction clutch is an essential component in the process of power transmission. Due to this importance, it's necessary to investigate the stresses and vibration characteristics of the rigid drive disc of clutch to avoid failure and obtain an optimal weight and cost. This work presents the numerical solution of computing the stresses and deformations during the steady-state period, as well as the vibration characteristics of the rigid drive disc of friction clutch. Furthermore, new models for rigid drive disc have been suggested. The response of the new suggested models have been compared to the classic model, the numerical results show that the stresses and vibration characteristics of rigid drive disc of clutch can be controlled by adjusting design parameters. They show as well that the suggested models improve the response of the friction clutch considerably. The ANSYS/WORKBENCH14 and SolidWorks 2012 have been used to perform the numerical calculation in this paper.
Abdullah, Oday Ibraheem, Schlattmann, Josef, Pireci, Emir
Sensitivity Analysis on a Synchronization Mechanism for Manual Transmission Gearbox2014-01-176804/01/2014
This paper presents the dynamic and analysis models of a typical synchronizer, which are mainly used to analyze the sensitivity of parameters of synchronizer on the gear shift performance. Because there are so many parameters namely coefficient of friction, cone angle, mean radius, blocker angle, etc, affected the synchronizer performance, which the times of experience will increase in a geometrical ratio if tested them one by one, it is almost impossible to evaluate all parameters by experience alone. Due to virtual prototype technology, the synchronizer parameterized virtual models can be built for the synchronizer studies. The parameterized virtual models of the typical synchronizers are developed with ADAMS. Then the gear shift process is simulated and analyzed for the given input parameters respectively. The models also predict the shift time and the peak of the shift force, and the model is validated by the good correlation between simulation results and test data. Finally, this
Li, Jinning, Luo, Fan, Luo, Yong, Zhang, Yunqing, Jiang, Ming
An Investigation of Heat Generation Due To Friction Using Finite Element Method2014-01-095404/01/2014
Most of failures in automotive friction clutches occur due to the excessive heat generated between the contact surfaces during the slipping period; for this reason, the accurate calculation of the heat generation during the slipping is considered an essential item in the successful design process to avoid the failures due to the high thermal stresses. A finite element technique has been used to study the temperature field, the heat generation and the contact pressure distribution when friction disc slides over the steel disc. Analysis has been completed using a three dimensional model to simulate the thermo-structural coupling in automotive clutches. ANSYS software has been used to perform the numerical calculation in this paper.
Abdullah, Oday Ibraheem, Schlattmann, Josef
Simulation of Clutch Inertial Effects on Gear Shifting, Synchronizer Capacity and Accelerated Testing of Synchronizers2013-01-280711/27/2013
In today's scenario, most of the OEMs use manual transmissions with synchronizer gear shifting system for ease of gear shifting. It gives very high fuel efficiency. Gear shifting is a customer touch point, hence it is very important to select adequate synchronizer capacity so that it will perform in better and last longer. To test the synchronizers, there are many test methods which give the idea about life of synchronizer and its performance, in different conditions. Regular synchronizer rig tests consume lot of time in deriving the results. So it is very important to find out a way which will give same results within short time period. To carry out the short time test or accelerated test, we need to understand the effect of various factors like reflected inertia, drag torque, differential speed, synchronizing time, and gear shifting force on synchronizer capacity. After understanding the effect of various factors on synchronizer, test method is developed to carry the test which will
Dhanal, Yuvraj V., Jadhav, Yuvaraj M.
Definition of Slippage Parameters of Friction Clutches for Different Installation Versions in Tractor Gearboxes2013-01-289411/27/2013
The aim of the work is to present the methodology for calculating the slippage parameters of friction clutches (the work and the time of slippage) for different installation options of such clutches in tractor gearboxes, and of the tractor acceleration time at different degrees of gear overlap. The authors suggest a universal diagram of tractor acceleration at gear shifting at different degrees of gear overlap in the gearbox, which is true for any interrelation of the times of gearing and slippage of the friction clutch. Based on the mathematical model of the tractor acceleration, suggested by the authors, a methodology was developed for calculating the slippage parameters of friction clutches (the work and the time of slippage) for a variety of installation options of such clutches in the gearbox during gear shifting with varying overlap degrees and the acceleration time of the tractor unit at each gear. The developed universal mathematical model allows defining - at the design stage
Sharipov, Valery, Dmitriev, Mikhail
Development of Advanced Propeller Damper (Shift Dampener System)2013-32-906810/15/2013
Generally, the gearshift mechanism for outboard motors shifts into forward or reverse gear without using the synchromesh arrangement (dog clutch engagement)(See Fig.1). This type of shift mechanism has advantages in simple structure and in saving space and cost, but at the same time, this is often the source of problem due to the abrasion caused by the hitting of gear against the dog clutch before the engagement, as well as large gearshift shock and noise. In addition, the outboard motor horsepower is getting bigger in recent years. As they are equipped with bigger and heavier engines and propellers, the shifting shock and noise tend to become more severe. For this reason, the improvement in this aspect is required. We looked into the way to reduce the shock and noise by means of propellers, because the propeller can be mounted and replaced easily, which allows the effective improvement to be spread to the outboard motors already in the market. Consequently, the advanced propeller
Kuroki, Yohei, Tsunekawa, Hiroyuki, Yukawa, Shunsuke
Development and Implementation of Hardware in the Loop Simulation for Dual Clutch Transmission Control Units2013-01-081604/08/2013
A control oriented model of a Dual Clutch Transmission was developed for real time Hardware In the Loop (HIL) applications. The model is an innovative attempt to reproduce the fast dynamics of the actuation system maintaining a step size large enough for real time applications. The model comprehends a detailed physical description of hydraulic circuit, clutches, synchronizers and gears, and simplified vehicle and internal combustion engine sub-models; a stable real time simulation is achieved with a simplification of the model without losing physical validity. After an offline validation, the model was implemented in a HIL system and connected to the TCU (Transmission Control Unit) via two input-output boards, and to a load plate which comprehends all the actuators. The paper presents a selection of the several tests that have been performed for the development of the DCT controller: electrical failure tests on sensors and actuators, mechanical failure tests on hydraulic valves
Cavina, Nicolo, Olivi, Davide, Corti, Enrico, Mancini, Giorgio, Poggio, Luca, Marcigliano, Francesco
The Design, Development and Industrialization of an New 8 Speed Automatic Transmission in China2013-01-127704/08/2013
Shengrui Transmission Limited Corporate (Shengrui) has developed a new 8 speed automatic transmission (SR 8AT) for front wheel drive (FWD) vehicle. The concept of SR 8AT is unique and different from the conventional automatic transmission. The design of the SR 8AT system and components are new and compact. By combining an innovative gear train which is similar with the conventional manual transmission and the simple planetary gear structure, SR 8AT achieved 8 speed with the shortest length of the FWD transmission, the competitive fuel economy and the smooth shift performance among comparable automatic transmissions.
Lu, Jan Gang
Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and ChartingJ2188_201207 (Historical)07/31/2012
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B). Some modern vehicles
Truck and Bus Powertrain Committee
High Efficiency, Hydro-Mechanical Passenger Vehicle Transmission using Fixed Displacement Pump/Motors and Digital Hydraulics2012-01-062404/16/2012
It is widely accepted that the plug-in hybrid vehicle is the most economically viable near-term solution to the petroleum and CO₂ problems associated with passenger vehicles. The battery and electrics costs of gas/electric plug-in hybrid vehicles can be significantly reduced with the use of a hydraulic transmission and the implementation of hydraulic regenerative braking. This has not been done to date due to the unavailability of a low cost, reliable, compact, and efficient hydraulic transmission. This paper describes a conceptual design of such a transmission and evaluates its performance using the attributes of existing components. The main causes of the lack of past success with hydraulic transmissions are the many drawbacks of variable-displacement hydraulic pumps and motors. This transmission is based on fixed displacement pumps and motors to avoid these drawbacks. The efficiency of the transmission is evaluated under various driving conditions and is equal to or better than
Lloyd, Robert H.F.
Parametric Importance Analysis and Design Optimization of a Torque Converter Model Using Sensitivity Information2012-01-080804/16/2012
Torque converters are used as coupling devices in automobile powertrains involving automatic transmissions. Efficient modeling of torque converters capturing various modes of operation is important for powertrain design and simulation, (Hroval and Tobler 1, Ishihara and Emori 2) optimization and control applications. Models of torque converters are available in various commercial simulation packages, Hadi et. al. 3. The information about the effect of model parameters on torque converter performance is valuable for any design operation. In this paper, a symbolic sensitivity analysis of a torque converter model will be presented. Direct differentiation (Serban and Freeman 4) is used to generate the sensitivity equations which results in equations in symbolic form. By solving the sensitivity equations, the effect of a perturbation of the model parameters on the behavior of the system is determined. A parametric importance analysis is performed on the model: the model parameters are
Banerjee, Joydeep, Adibi asl, Hadi, Lashgarian Azad, Nasser, McPhee, John
Method for Identification of the Kiss Point as well as Takeoff Point of a Hydraulically Actuated Friction Clutch2012-01-011204/16/2012
For control of most automatic transmissions with wet clutches (e.g. dual clutch transmission), it is important to know the kiss point with high accuracy. The kiss point describes the value of the control variable for which the friction clutch begins to transmit torque. Another significant value during the filling process of a wet clutch is the takeoff point. This is the hydraulic pressure which causes the clutch piston to begin to move. This paper presents an innovative approach that enables the joint determination of the kiss point as well as the takeoff point in only one identification procedure. In contrast to existing methods, this method is able to identify both points without the necessity for undesired auxiliary system excitation. Therefore it is possible to reduce wear on system components such as synchronization rings. The method presented in this paper analyzes the measured filling pressure characteristic over time as the system response to a defined excitation. The
Tarasow, Alex, Bohn, Christian, Wachsmuth, Guido, Serway, Roland, Eisbach, Marcel, Zhao, Qi, Bauer, Georg
Inside ZF's nine-speed transaxle for 201311AEID1101_0211/01/2011
AEI travels to Friedrichshafen for an exclusive look at the development and technology behind the 9HP-the industry's first nine-speed transaxle slated for MY2013 production. With its 9.84 ratio spread, clever controls, and compact packaging, ZF's new nine-speed automatic transaxle will offer OEMs capability to increase fuel economy in their front-wheel-drive vehicles by 10-16% at 75 mph (121 kph), based on the NEDC cycle, when the gearbox is launched for MY2013 production next year. Few new transmissions have caused as much buzz within the industry as the 9HP. ZF announced it at the 2011 Detroit auto show but provided almost no details of its inner workings. But this summer, ZF's top engineers gave a select group of media, including AEI, a look inside the 9HP and its development. The visit to the company's Friedrichshafen R&D center included a long test drive of three 9HP-equipped mules (see sidebar).
Brooke, Lindsay
Multi-domain Modeling and Simulation of AMT Based on Modelica2011-01-123704/12/2011
The automatic mechanical transmission (AMT) was designed by automobile manufacturers to provide a better driving experience, especially in cities where congestion frequently causes stop-and-go traffic patterns. It uses electronic sensors, processors, hydraulic or pneumatic actuators execute clutch actuation and gear shifts on the command of the driver. Such systems coupled with various physical domains have great influence on the dynamic behavior of the vehicle, such as shift quality, driveability, acceleration, etc. This paper presents a detailed AMT model composed of various components from multi-domains like mechanical systems (clutch, gear pair, synchronizer, etc.), pneumatic actuator systems (clutch actuation system, gear select actuation system, gear shift actuation system, etc.). Various components and subsystem models, such as the vehicle, engine, AMT, wheels, etc., are integrated into an overall vehicle system model according to the transmission power flow and control logic
Jiang, Ming, Chen, Wei, Zhang, Yunqing, Chen, Liping
Simulating and Correlation of Vehicle Startability on Grade Maneuvers2010-36-032510/06/2010
The behavior knowledge of the vehicle on uphill maneuvers - startability on grade, is an important metric for sizing powertrain components, such as the engine torque, clutch, first and reverse gear ratios, final drive and tire sizes. During the uphill maneuver, all components of the powertrain are subject to efforts that determine the vehicle performance in this condition. The analysis of this maneuver, for a front-wheel-drive vehicle, is evaluated in this article, through a correlation of a computer program developed in Matlab-Simulink, with experimental measurements performed on the vehicle at the track, becoming an important tool for analysis of passenger vehicles subject to these conditions present on Brazilian streets.
Junior, Jacob Ferezini
Kinematic Discrepancy Minimization for AWD Terrain Vehicle Dynamics Control2010-01-189510/05/2010
Stability of motion, turnability, mobility and fuel consumption of all-wheel drive terrain vehicles strongly depends on engine power distribution among the front and rear driving axles and then between the left and right wheels of each axle. This paper considers kinematic discrepancy, which characterizes the difference of the theoretical velocities of the front and rear wheels, as the main factor that influences power distribution among the driving axles/wheels of vehicles with positively locked front and rear axles. The paper presents a new algorithm which enables minimization of the kinematic discrepancy factor for the improvement of AWD terrain vehicle dynamics while keeping up with minimal power losses for tire slip. Three control modes associated with gear ratio control of the front and rear driving axles are derived to provide the required change in kinematic discrepancy. Computer simulation results are presented for different scenarios of terrain and road conditions. The
Vantsevich, Vladimir, Augsburg, Klaus, Shyrokau, Barys, Ivanov, Valentin
Independent Power Take Off (IPTO) with Mechanically Operated Multiplate Wet Clutch for Agricultural Tractors2010-01-198210/05/2010
Tractors along with implements are used to prepare the soil. There are two broad classification in implements attached, one is passive or trailed implements and other one is active tilling implements which will take drive from engine through Power Take Off (PTO). The drivelines for transmission and PTO should have clutches to engage / disengage them from the engine while changing gears and switching PTO On/Off respectively. In present scenario, there are independent clutches for both drivelines to operate PTO driven implements without disrupting vehicle speed. In general, IPTO is being achieved by dry clutch which is integral with engine mounted clutch operated by separate linkages or by hydraulically operated wet clutch located in PTO driveline after auxiliary pump. An attempt is made with mechanically operated wet clutch in the PTO driveline to have an IPTO. Design proposals for mechanically operated multiplate wet clutch and linkage mechanism for engagement/disengagement were
Range Gounder, Ramaraj, Sriraman, Sethuraman, Verma, Rakesh
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