Browse Topic: Dry disc clutches

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Modeling and Design of a Wet Clutch Offset Compound Gear Transmission for Dual-Speed Rotorcraft ApplicationsF-0076-2020-1633610/5/2020
This paper develops a lumped-parameter multi-plates wet clutch Offset Compound Gear (OCG) transmission dynamics and its thermal model for dual-speed rotorcraft applications with an active clutch slip-speed control. This model includes the Reynolds equation for the clutch oil film thickness, the clutch thermal model, the clutch transferred torques (viscous and asperity torque) and the clutch disengagement model. The wet clutch/OCG transmission system is implemented in Matlab® Simulink™ to manage the upshift clutch temperature rise, which is a main issue need to handle for a dual-speed helicopter transmission. Here, the clutch temperature rise is treated by injecting a certain amount of coolant during engagement so that the temperature rise for the wet clutch is much lower than that of an dry clutch. In order to transfer a required torque using the available power, the sizing of the wet clutch could be evaluated via the developed wet clutch/OCG transmission model. This study shows that the temperature rise drops as the wet clutch oil flow rate increases adding extra weights compared with the dry clutch. The simulation also captures a phenomenon that a larger clutch engagement pressure might be required for the wet clutch to transfer the same torque since the wet clutch oil viscosity drops as the oil temperature increases during the clutch engagement.
DeSmidt, Hans, Bill, Robert, Su, Xiaowen, Smith, Edward
An LQR Approach of Automatic Transmission Upshift Control Including Use of Off-Going Clutch within Inertia Phase2020-01-09704/14/2020
This paper considers using linear quadratic regulation (LQR) for multi-input control of the Automatic Transmission (AT) upshift inertia phase. The considered control inputs include the transmission input/engine torque, oncoming clutch torque, and traditionally not used off-going clutch torque. Use of the off-going clutch has been motivated by discussed Control Trajectory Optimization (CTO) results demonstrating that employing the off-going clutch during the inertia phase along with the main, oncoming clutch can improve the upshift control performance in terms of the shift duration and/or comfort by trading off the transmission efficiency and control simplicity to some extent. The proposed LQR approach provides setting an optimal trade-off between the conflicting criteria related to driving comfort and clutches thermal energy loss. It ensures tracking a linear-like profile of oncoming clutch slip speed reference, which was found to be nearly optimal based on control trajectory optimization results. A special attention is given on proper implementation of nonlinear energy loss term through LQR cost function cross term and using a clipped optimal control approach to provide that the clutches (described as torque source elements) can only dissipate energy. The LQR approach was applied to a fifth-order powertrain model and different upshift control scenarios ranging from the use of single clutch towards using both clutches and transmission input/engine torque reduction. It is shown that the LQR approach can reproduce Pareto frontiers obtained by multi-objective control parameter optimization demonstrating that apart from being used in closed loop controls, the proposed LQR approach can also be exploited for computationally efficient (off-line) optimization purposes.
Cvok, Ivan, Deur, Josko, Ivanovic, Vladimir, Zhang, Yijing, Fujii, Yuji
Dynamics and Control of Gearshifts in Wet-Type Dual Clutch Transmission for BEVs2020-01-07674/14/2020
The dual clutch transmission is one of the possible choices for electric vehicle drivelines. The basic principle and control mode of shifting of wet dual clutch transmission are introduced, and the dynamic process of shifting of wet double clutch transmission is studied. Combined with the dynamic model of the wet clutch engagement process, the difference between the dynamic characteristics of the dual clutch transmission modeling using the Coulomb friction model and the dual-clutch transmission model using the average flow model and the micro-convex contact theory is analyzed. The shift control strategy of the dual clutch transmission proposes a correction method to improve the shifting smoothness. Studies have shown that the torque response of the wet clutch has significant hysteresis, and the improved control algorithm can significantly improve the shifting smoothness of the wet dual clutch transmission. Based on the dynamic model of the wet clutch, the torque interruption of the shift control strategy of the dual clutch transmission is studied, and the method of improving the shift smoothness by the correction of the shift control strategy is proposed.
Lou, Zhenxiong, Duan, Yupeng, Zhang, Yunqing
Analytical Estimation of Clutch Life for Manual Transmission2019-01-03354/2/2019
The clutch is the connecting link between engine and the power train. It connects and disconnects the engine to the gearbox as per the wish of the driver. Clutch has a friction disc which acts like a fuse wire which wears in the process of the connection. This paper tries to calculate the clutch life analytically (In terms of Kms. run by vehicle), of automotive vehicles having manual transmission. As the clutch engages and disengages the engine to the gearbox, during this time due to slippage, energy is dissipated which results in the wear of the clutch disc. It calculates life based on the volumetric wear of the clutch disc and wear allowance available. The work done by other people in this domain include the empirical estimation of clutch life based on the past data, effect of the surface topography on the friction characteristics of the wet clutches, modeling of clutch housing and facing temperature for the estimation of the clutch life of a manual transmission etc. The present work simplifies the estimation of clutch performance using fundamental principles, without high end analysis software or past data. It helps to estimate the clutch performance in the concept stage itself thereby saving time and labor making the selection of the right clutch at the very first time. The complete work was done in-house and its purpose was to estimate the life of the clutch in terms of vehicle run in Kms. The results estimated were closely compared with respect to the field data of vehicles. This tool will be of immense help in such a fast changing automotive world where competition is cut-throat and product development time is shrinking continuously.
Mishra, Anurag, Chollangi, Damodar
Planetary Power Split Device for Hybrid Vehicle Powertrain2019-01-03704/2/2019
This work looks into the development of power-split planetary gear set for hybrid vehicle. The aim is to research possible solution of hybrid powertrain integrating DHT (Dedicated Hybrid Transmission), which will comply with demands of compact cars, where simplicity and low price is a primary focus. On the other hand, this solution must offer full-hybrid capability. The search of new solution is focused on the usage of one electric motor in combination with internal combustion engine, the planetary gear set (PGS) and stepped transmission. For low forward speeds and reverse the electric drive can be used. The low forward speed can be ensured also by combination of electric motor and ICE, the medium speed range will be covered by powersplit or combination/addition of power of ICE and electric motor, for highway usage the direct drive from ICE via stepped transmission is envisaged. Most of the functional modes allow also the electric energy recuperation. The paper will present the overview of existing solutions; the literature survey will be dedicated for designs with single electric motor mainly. Further will be included the description of newly proposed mechanism, the shift table and full description of all functional modes. For demonstration and simulation purpose was chosen 1.0 L spark ignition engine in combination with 48 V electric motor - the results will be included in the paper. It was decided to build a plastic demonstrator of the newly invented DHT for the functional check.
Kanera, Jaroslav, Achtenova, Gabriela, Kruta, Michal
Modeling, Control, and Adaptation for Shift Quality Control of Automatic Transmissions2019-01-11294/2/2019
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 effort. In the current work, novel model-based methods are used to accomplish feedforward control of gearshifts, involving offline calibration of fill and torque phase control parameters and learning control of the fill phase. Towards this end, a physics-based model of the oncoming clutch involved in an upshift of a production automatic transmission was developed and experimentally validated against test bench experiments for a wide variety of inputs and operating conditions. The resulting model is used to generate a feedforward controller, offline model-based calibration algorithm, and a learning controller that corrects for clutch under-fill and over-fill. The effectiveness of the resulting controller is validated by simulation studies using the experimentally validated transmission hydraulic system model, in conjunction with a powertrain model. In particular, it is demonstrated that the learning controller corrects for initial under- or over-fill error in two to three gearshifts. Convergence and robustness properties, and transient performance of the learning controller are also discussed.
Mishra, Kirti Deo, Cardwell, Gilbert, Srinivasan, Krishnaswamy
Energy Based Analytical Study of Effect of Engine Calibration, Clutch Modulation on the Life of Dry Clutch in View of City Traffic Using Road Load Data2019-26-03311/9/2019
Single plate dry clutch is one of the most abuse components in the vehicle. With the growing population of traffic in cities, useful life of clutch is affected drastically which is evident from the rise in complaints on clutch from metropolitan cities. The governing design parameter, which affects the life of clutch, is the energy dissipated in clutch per unit area of friction lining of clutch disc. The life of clutch is affected by many factors like vehicle weight, engine torque, driveline ratios, friction lining, size of clutch, which are taken into consideration during design stage of the clutch. Apart from these factors, one more factor, engine calibration, affects the clutch life drastically. However, it is not taken into consideration during design stage owing to its inherent nature as it gets matured over the vehicle development program. Engine calibration, especially driven idle speed calibration of engine in 1st, 2nd and 3rd gear for a particular vehicle, governs the vehicle behavior and drivers maneuvering of clutch, brake and accelerator in city traffic. This paper presents study done using road load data collected in metropolitan city traffics to understand drivers maneuvering in traffic, effect of engine calibrations on typical maneuvering, using energy dissipated in clutch as basis. The paper discusses the effectiveness of changes done in driven idle speed calibration of engine with two vehicle, having different calibrations, driven back to back in city traffic. As energy dissipated in clutch is used as basis, the study indicates avenues in engine calibration for improvement in clutch life.
Mohire, Sujit, Katarki, Shrirang, Chaskar, Mithun, Uttamani, Rahul, Tendulkar, Vishveshvar
AMT Reverse Gear Engagement Dynamics and Control2019-26-00461/9/2019
Now a day’s automated manual transmissions (AMT) are getting popular because of hassle-free gear shifting and improved fuel economy. OEMs are converting their existing manual gearbox to AMT gearbox with solution like hydraulic or electric AMT kit that replaces the manual shift mechanism to automated actuators. Generally, in manual gearbox, the operational principal of reverse gear is sliding mesh. Due to sliding mesh gear arrangement, it can create interruption for gearshift while controlling shift actuators. In this paper, reverse gear shift arrangement and its operational dynamics at different operating condition has been studied and analyzed in detail. Based on status of vehicle, to ease the gearshift, engagement flow process proposed. The control methods that increases probability of smooth and easier shifting in all operating condition discussed in detail. The developed control algorithm discussed along with its implementation on real vehicle and results.
Prajapati, Gaurang, Penta, Amar, Warule, Prasad
Necessity of Advance Damper Technology for Future Agriculture Domain2019-26-01931/9/2019
There is an increasing demand from end-users of tractors for longer clutch durability, reduction in driver fatigue and comfort during field operations. Tractor manufacturers are moving towards Wet Clutch Pack with torsion dampers to meet this emerging customer needs. However, in Conventional Torsion Dampers, there is a technical challenge to withstand harsh clutch engagement or high unexpected impacts of agri-implements, which are common in field operations. This is in addition to, torsional vibrations produced by the power-train. There are constraints, to further optimize a conventional damper without compromising important parameters like factor of safety, noise and durability issues. Hence the proposed next generation damper technology can meet all the new technical requirements and can ensure smooth and durable power shift transmission in tractors. This case study has been done with help of SCHAEFFLER’s tailor made “Tornado Instrument” and “Software” by acquiring real time data (directly from agricultural field operations) from several OEMs followed by quantitative analysis of unexpected impacts, and addressing this issue with next generation damper technology.
Bagadekar, Vijaykumar Shankar, Alavilli, Satya Pavan, Kadhar Maideen, Salim Malik, Rajendran, Ashok Kumar, Radhakrishnan, Padmanaban, Soni, Sandeep
Influence of Clutch Tribodynamics on Drivetrain Noise, Vibration and Harshness, (NVH), Phenomena2018-01-15376/13/2018
Limiting problematic Noise, Vibration and Harshness (NVH) phenomena in the modern automotive drivetrain is a task of critical importance. The result of such phenomena is the aggravation of the driver, which results in a reduced perception of vehicle quality. Each phenomenon can be characterized by a distinct frequency range. The aim of the current study is to assess the influence of the interfacial frictional behavior of the dry friction clutch components on the drivetrain dynamic behavior. The dynamics of the system (in terms of its stability) are studied. Surface data from the clutch components are critical to understanding the complex engagement process. The coefficient of friction was measured using a rotary tribometer at representative slip speeds and contact pressures. To aid the analysis infinite focus microscopy was used to measure the geometric properties of the constituent components of the drivetrain. The current approach allows for improved understanding of the drivetrain’s dynamic behavior. The improved understanding of the coupling between tribological characteristics and drivetrain system dynamics can lead to the mitigation of future NVH issues.
Minas, Ilias, Morris, Nicholas, Theodossiades, Stephanos, O'Mahony, Martin
Virtual Simulation for Clutch Thermal Behavior Prediction2018-37-00215/30/2018
The clutch is that mechanical part located in an internal combustion engine vehicle which allows the torque transmission from the shaft to the wheels, permitting at the same time gear shifting and supporting engine revolutions while the car is idling. This component exploits friction as working principle, therefore heat generation is in its own nature. The comprehension of all the critical issues related to thermal emission, and also of the principal physical parameters driving the phenomena are a must in design phases. The subject of this paper is the elaboration of an accurate, but also easy to use and easily replicable, methodology to simulate thermal behavior of a clutch operating inside its usual environment. The present methodology allows to prevent corrective actions in the last phase of the projects (real testing), such as changes in gear ratios, that likely worsen CO2 emissions, permitting to achieve the wished thermal performance of the clutch avoiding late changes. Using computational fluid dynamics, coupled with thermal-FEM software, working limits can be foreseen, and strengths or design flaws can be highlighted. The approach for the problem is typically bottom-up: starting with the simulation of a reduced domain around the clutch and going towards the complete car thermal simulation. Here, the aim is to show the setup of a thermal simulation, considering boundary conditions, initial conditions and geometry details. Starting from a reduced computational domain, many more attempts can be run and a final model more easily found. Consequently, a sensitivity approach to several aspects will be adopted: heat generation location and temperature of different components can be considered to evaluate the impact on the clutch thermal behavior. The paper will show the correlation between experimental and virtual results for both complete and reduced models, to identify the best trade-off between computational efforts and accuracy.
Tosi, Fabio, Gautero, Matteo, Lorefice, Laura, Paola lng, Nicola
Electro-Hydraulic Shuttle Transmission and Control for Tractors with Non-Electronic Engine2018-01-03904/3/2018
Recently, emerging technological developments in powertrain were mostly accompanied with electronics for efficient and precise control of various powertrain systems like engine, transmission, hydraulics, etc. Agricultural tractors are of no exception to this context. Most of the higher horsepower tractors above 50 HP are equipped with modern transmission systems such as Power-shuttle, Power-shift etc. having their wet clutch transmission and diesel engine controlled by an Electronic Control Unit. This is possible only with an engine that receives and provides electronic signals. Whereas a tractor with mechanical (non-electronic) engine is of predominant use in the Indian farm lands due to their low cost and immediate availability compared to that of an engine equipped with high-end electronics. Hence, there is a demand for low cost drivetrain with improved controls and without engine electronics. This research work depicts on one such development, where an effective power shuttle transmission system and controls were developed for a non-electronic engine tractor. The multi-plate wet clutch shuttle transmission is electro-hydraulically controlled, thus eliminates the operator fatigue due to frequent clutch pedal application with improved vehicle launch and smooth shuttle shift ability. This research work also address the safety features for protecting and increasing the life of system components like clutch slippage, energy dissipation, power consumption. Additional system protection was also done through fault mode diagnosis via safety features such as anti-stalling, speed cut off shuttling, wrong direction detection, etc with minimal sensors and powertrain components.
Rajagopal, MahendraMohan, M A, Velmurugan
Fuel Efficient Speed Optimization for Real-World Highway Cruising2018-01-05894/3/2018
This paper introduces an eco-driving highway cruising algorithm based on optimal control theory that is applied to a conventionally-powered connected and automated vehicle. Thanks to connectivity to the cloud and/or to infrastructure, speed limit and slope along the future route can be known with accuracy. This can in turn be used to compute the control variable trajectory that will minimize energy consumption without significantly impacting travel time. Automated driving is necessary to the implementation of this concept, because the chosen control variables (e.g., torque and gear) impact vehicle speed. An optimal control problem is built up where quadratic models are used for the powertrain. The optimization is solved by applying Pontryagin’s minimum principle, which reduces the problem to the minimization of a cost function with parameters called co-states. The proposed algorithm assumes piecewise constant slopes and speed limits, and it solves the transition vehicle speeds for each junction of such segments. In addition, a method to extract route information from digital maps is presented, which complies with the proposed optimization algorithm. The algorithms are evaluated in simulation, using Autonomie, a simulation tool for vehicle energy consumption modeling. The optimal control trajectory (e.g., torque, gear) is first computed offline. It is then applied in an open-loop fashion in online simulation, using a forward-looking model of the vehicle in Autonomie. Simulation results show over 8% fuel saving for two selected real-world routes.
Shen, Daliang, Karbowski, Dominik, Rousseau, Aymeric
Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis2018-01-04044/3/2018
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 observed in road load data. Cumulative energy calculated from all these events was extrapolated for stated life of the clutch, for vehicle application under consideration. A test cycle was derived considering maximum energy dissipated in engagement events, clutch engagement pattern and maximum temperature observed inside clutch housing, for rig testing. The life predictions and failure modes observed with this test schedule were evaluated against the field vehicles and it showed a good correlation. This paper proposes a methodology to derive test schedule for clutch life prediction based on energy dissipated in clutch and using road load data. The test on the rig with such schedules provides better avenues to shorten the development time line of clutch system as well as vehicle driveline.
Mohire, Sujit, Uttamani, Rahul, Tendulkar, Vishveshvar, Katarki, Shrirang, Patil, Shahaji
A New Rotating Wedge Clutch Actuation System2017-01-244110/8/2017
Rotating clutches play an important role in automatic transmissions (AT), dual-clutch transmissions (DCT) and hybrid transmissions. It is very important to continually improve the transmission systems in the areas such as simplifying actuator designs, reducing cost and increasing controllability. A new concept of electrical motor driven actuation using a wedge mechanism, a wedge clutch, demonstrates potential benefits. This wedge clutch has the characteristics of good mechanical advantage, self-reinforcement, and faster and more precise controllability using electrical motor. In this paper, a new rotating wedge clutch is proposed. It presents a challenge since the motor actuator has to be stationary while the clutch piston is rotating. A new mechanism to connect the motor to the wedge piston, including dual-plane bearings and two mechanical ramp linkages, is studied. The design and verification of the physical structure of the actuator are discussed in detail in the paper.
Ding, Zhao, Chen, Li, Yin, Chengliang, Yao, Jian, Lee, Chunhao, Samie, Farzad
Fluid-Solid Coupled Heat Transfer Investigation of Wet Clutches2017-01-244210/8/2017
The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in a vehicle transmission system. A two-phase coupled heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding by CFD method. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area. The outer radius temperature is higher than the inner radius temperature at the contact face. The subregions which divided by the radial grooves show similar temperature distribution. The temperature besides the groove in each subregion is not symmetric and the higher temperature occurs at the area near the leading edge. On the symmetric plane, similar asymmetric temperature distribution can also be found. The contact face temperature is about 10 K higher than the symmetric plane temperature. Further, the temperature at the bottom of the groove is about 1 to 6 K lower than other regions. The average temperature on the contact plane and symmetric plane increases almost linearly after the starting stage and the temperature difference between the two planes becomes larger with increasing time. The present study would provide basic insight in the thermal analysis of sliding friction pair and can be used for temperature control and cooling device design for wet clutches and brakes.
Xiao, Bingqing, Wu, Wei, Hu, Jibin, Yuan, Shihua, Hu, Chenhui
Combined Spatter and Immersion Type Oil Cooling System for Multi Disc Wet Clutch Transmission in Tractors2017-28-19767/10/2017
The utility of tractors in India has grown and is growing. Other than in agricultural area, it finds use in non-agricultural and construction/ earthmoving applications like loaders, dozers, power source, etc. The tractors that are subjected to heavy duty cycles are mostly with conventional dry type clutches. These types of dry clutch when operated in heavy application generate large amount of heat within shorter period of time on the surface of friction discs. This increase in disc surface temperature weakens the friction material property & bonding element leading to deterioration and decreasing the life of clutch. This curtails the clutch life extensively and is a big challenge to farmers and tractor users. The frequent clutch failures not only increases the operating cost, but also the servicing of clutches in the tractor fitted with heavy attachments leads to a higher downtime and service cost. To overcome this challenge, an innovative solution in the oil spatter concept has been evolved to provide active circulation of oil to the multi disc wet clutch friction discs while in engaged conditions. The system is designed in such a way that it cut-off the oil flow in to the clutch unit while clutch is disengaged. This oil spatter system evenly carries away the heat generated across friction & steel disc surface through the groove patterns in the discs. This combined spatter and immersion type oil cooling provides improved heat removal and significantly reduces the drag torque and reduces power loss. This oil spatter clutch system will provide a fit and forget trouble free clutch system to farmers with significantly higher ROI.
Narayana Rao, Suresh Kumar
Oil Sheer Clutch Cuts Downtime for Metal Stamping PressTBMG-270746/1/2017
In the metal stamping business, precision, repeatability, and uptime are key. But stamping accuracy suffers when improper tension on the coil feeders incorrectly supplies metal to the presses, resulting in off-spec parts and increased rejections. ART Technologies of Fairfield, OH, relies on an oil shear clutch brake to supply constant, reliable tension on the coil feeding to one of its 400-ton presses to produce the precision and repeatability it needs, with no downtime for maintenance or adjustment. When the plant is working 20 hours a day, that uptime is as critical as the tolerances it maintains.
Simulation and Experiment of Characteristics of Transmitted Torque of Dry Clutch Engagement2017-01-04023/28/2017
Based on the formation mechanism of engaging force of clutch, the engagement was divided into four stages: idle stage, cushion spring stage, diaphragm spring stage and locked stage. The mechanism of transmitted torque in each stage was analyzed and the transmitted torque model of clutch was deduced. Multi-load step analysis method based on finite element was used to analyze the coupling load-deformation characteristics of diaphragm spring and cushion spring in engagement, and the change laws of engaging force, diaphragm spring force and release bearing force were achieved and their coupling interaction were studied. And then change of friction coefficient of clutch with oscillating temperature was measured on friction test rig, and effect of temperature on transmitted torque was further discussed. Finally, simulation results of transmitted torque were validated by the experiment. Results indicate that the transmitted torque in clutch engagement has a nonlinear characteristic. The transmitted torque is increased slowly in the initial stage of engagement and has an approximate linear increase in the middle and late stage of engagement. And the transmitted torque increases first and then decreases with the rise of temperature in friction pairs, and effect of temperature on transmitted torque in the diaphragm spring stage is more obvious than the cushion spring stage.
Zhang, Zhigang, Xiaohui, Shi, Bin, Ye
Brake Clutch Assisted Mode Transition Control for Compound Power-Split Vehicle2017-01-11703/28/2017
Because a compound power-split transmission is directly connected to the engine, dramatic fluctuations in engine output torque result in strong jerks and torque losses when the hybrid vehicle is in mode transition from electric drive mode to hybrid drive mode. In order to enhance ride comfort and reduce the output torque gap during mode transition process, a brake clutch assisted coordinated control strategy was developed. Firstly, the dynamic plant model of the power-split vehicle including driveline model, engine ripple torque and brake clutch torque was deduced. Secondly, the brake clutch assisted mode transition process was analyzed, and the output torque capability was compared between cases of both brake clutch assisted and unassisted mode transition process. Thirdly, a coordinated control strategy was designed to determine the desired motor torque, brake clutch torque, engine torque, and the moment of fuel injection. Finally, the effectiveness of coordinated control strategy was verified by vehicle test. The experimental results indicate that the proposed strategy was effective to suppress driveline speed oscillations during engine cranking phase, and reduce the engine cranking time.
Zhang, Tong, Wang, Chen, Zhou, Wentai, Cheng, Huijun, Yu, Haisheng
Driveability Improvement with Innovative Toyota 8 Speed Automatic Transmission Control2017-01-11093/28/2017
To meet increasing driveability expectation and government stringent fuel economy regulations reducing CO2 emissions of passenger cars; Toyota developed a new 8-speed automatic transmission "Direct Shift-8AT". Direct Shift-8AT is the first stepped automatic transmission model based on “TNGA” philosophy. New models which received Direct Shift-8AT are the new Camry, Highlander and Sienna. Direct Shift-8AT has an innovative control method with gear train and torque converter models, providing enhanced driveability and fuel economy performance through high efficiency transmission technology. This paper describes details of the new technology and vehicle performance.
Ota, Keisuke, Kondo, Masami, Shinohara, Shuntaro, Tsukamoto, Norihiro, Masunaga, Seiji, Sagawa, Ayumu
Development of High Fidelity Dynamic Model with Thermal Response for Single Plate Dry Clutch2017-26-02601/10/2017
Single plate dry clutch is most commonly used in automotive transmission. This paper proposes a unique approach of modelling a single plate dry clutch in Simulink and Simscape simulation environment. Clutch model is divided into two subsystems as translational and rotational. The translational system is linear system of diaphragm and cushion spring as a two-degree freedom system. Nonlinearity of the diaphragm and cushion spring has been modelled based on experimental data. This enables to simulate friction torque variation during clutch engagement. In rotational system, frictional torque generation between flywheel-clutch disc and pressure plate-clutch disc has been modelled separately. This novel approach of developing separate friction models helps in understanding variation in torque carrying capacity due to rise in the temperature of the friction pads because of frictional and engine heat. The variation of friction coefficient with rise in temperature has been taken into account based on experimental data. The model is simulated for different conditions and results are discussed.
Penta, Amar, Warule, Prasad, Patel, Sanjay, Dhamija, Lohit
Efficient Dual Clutch Transmission Family for Transversal, Transaxle Powertrains2017-26-00361/10/2017
The reduction of CO2 emissions at vehicle level through the improvement of transmission efficiency represents the essential goal of transmission development engineers. New requirements, such as the recovery of the kinetic energy of the vehicle while coasting, the hybridization of drivetrains and autonomous driving, are challenges that can best be overcome with automatic transmissions. Dual clutch transmissions (DCT) with power-on-demand actuation systems offer a particularly efficient method of meeting the new requirements. However, many markets show vehicle applications with production volumes of less than 100.000 units per year. FEV’s new DCT family is conceived especially for customers in these markets. The re-use of proven subsystems which are already in series production results in a "business case" for applications with lower volumes also. This article introduces this transmission family.
Steinberg, Ingo, Freiholtz, Dan, Hellenbroich, Gereon
Low-Cost Powertrain Platform for HEV and EV2017-26-00881/10/2017
Currently known hybrid systems are technically complex, cost-intensive and referring to this for many end-customers not available. Under this boundaries IAV has developed a cost-optimal concept of an efficient and modular powertrain platform for electric and hybrid vehicles. The system is based on one unity gear-set for up to three speeds, which enables seamless shifting with only one friction based clutch. With this platform powertrains can be realized by using a maximum number of carry over parts (COP) for electric vehicles as well as for hybrids. The derivable hybrid powertrains of the platform system are designed for 48V electric motors (EM) which enables the maximum cost potential in combination with the realized gear set and transmission technology. The real simple powertrain platform concept is furthermore scalable for different vehicle segments optionally with or without a hybrid option.
Danzer, Christoph, Liebold, Jens, Schreiterer, Erik, Mueller, Jörg
Development of Indigenous Automated System to Evaluate Clutch Performance Under Real World Conditions2017-26-03201/10/2017
Automotive clutches form the most important component in the drive line which acts both as torque transmitter and as a fuse. Testing clutches, in the vehicle assembly, poses certain limitations. In this context the automotive clutch, as a component, needs to be evaluated to determine various performance parameters like wear, load loss, slipping torque, slipping time etc. to meet desired design, performance and durability requirements. It is very important to simulate engine and vehicle conditions in terms of operating environment, speed and load accurately while evaluating above parameters. This creates lot of challenges to design and develop a test rig capable of evaluating complete clutch performance. Very limited options are available for such test rigs worldwide. In India, no manufacturer provides such indigenous test rigs. Developing an indigenous, cost effective clutch test rig was the need of the hour. An indigenous, cost effective and customized clutch test rig was developed in collaboration one of India’s leading clutch manufacturer. The present such test rig developed caters to multi plate, wet clutches for 2W vehicles ranging between 100 cc to 1200 cc engine capacity; the concept can be extended for testing of dry type clutches also. The test rig is designed to operate and test clutches up to 300 Nm and 10000 rpm with complete electrical inertia simulation. Major challenges for such tests rigs are accuracy & response times for speed and torque control, maintaining engine environment conditions in terms of oil/air flow & temperature, precise, variable and fast clutch actuation etc. This paper elaborates the challenges faced in conceptualization, design and development of the clutch test rig in terms of different aspects viz.; controls automation, accuracy, precision and correlation to real world conditions and results.
Lavangare, Pravin, Jahagirdar, Ashutosh, Mengaji, Parag, Karle, Manish, Deshpande, Anand, Shailesh Karle, Ujjwala, Kulkarni, Ashok, Uthaman, Sreekumar, Dere, Amol
Modelling, Analysis and Simulation of Clutch Engagement Judder and Stick-Slip2016-01-235510/17/2016
Analytical and numerical study is carried out to study the behavior of stick-slip and judder phenomenon during engaging and disengaging of the automotive clutch. For this purpose, a four degree of freedom torsional power train lumped mass model is developed. This torsional vibration system includes engine-flywheel, clutch, gear box and vehicle drive line, which are connected to each other by shafts. Equation of motion of the system is developed and initially a stability analysis is carried out for various gradients of coefficient of friction using eigen value analysis. Later, a numerical simulation is carried out to analyze the judder and stick-slip phenomenon using commercially available mathematical tool MATLAB. It is observed that the clutch stick-slip is increased with increase in external torque and clutch pressure fluctuations.
Sivanesan, M, Jayabalaji, G
Estimation of the Clutch Characteristic Map for an Automated Wet Friction Clutch Transmission2016-01-11134/5/2016
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 functions in these two dimensions. The parameters of this model are estimated using different identification algorithms, in this case a non-linear recursive and a non-recursive identification algorithm. Both estimation algorithms result in a characteristic map of the clutch behavior. A further advantage of the presented approach is the normalization during the estimation process of the slip-based function with the cost function. Thus, the original torque characteristic can be used as fallback if the identification of the slip-based part still need reference data to converge or shows an implausible behavior.
Arndt, Thorsten, Tarasow, Alex, Bohn, Christian, Wachsmuth, Guido, Serway, Roland
An Automotive Clutch Control for Vibration Suppression of Dual Clutch Transmissions2016-01-11144/5/2016
A dry clutch induces judder phenomenon which is caused by variations in the vehicle load condition and frictional material properties. Such a problem may lead to the stick-slip limit cycle that results in undesired longitudinal vibrations of vehicles. To solve this problem, a vibration suppression control is proposed. The amplitude of vibrations is detected by the signal conditioning from the measurements with the transmission input shaft speed and the wheel speed sensors. Based upon this, a perturbation torque is applied additionally on the nominal launch controller to make the drive shaft oscillation vanish. It can be achieved by the control design without any extra hardware cost. Finally, experimental results confirm the effectiveness of the proposed mechanism.
Kim, Jinsung
Bond Graph Analysis of Automatic Transmission Shifts including Potential of Extra Clutch Control2016-01-11464/5/2016
New generation of torque converter automatic transmissions (AT) include a large number of gears for improved fuel economy. Control requirements for such transmissions become more demanding, which calls for the development of new shift optimization and analysis tools. This paper presents two contributions to the field of transmission dynamics analysis: (i) bond graph method-based shift transient analysis, and (ii) deriving a unique set of conditions for beneficial use of a third (normally-open) clutch for any upshift or downshift, with emphasis on inertia phase. The derived conditions are examined on an example of 10-speed AT based on the clutch torque input trajectory optimization results. The examination results point out that the extra clutch has a potential of significant performance improvement for any single-transition upshift in the inertia phase, in terms of reduced vehicle jerk RMS value due to the suppressed inertia bump effect. The shift quality improvement is possible in the torque phase, as well, but it is of much smaller extent when compared to that related to the inertia phase.
Ranogajec, Vanja, Deur, Joško, Coric, Mirko
Sliding Mode Adaptive PID Control of an Automotive Clutch-By-Wire Actuator2016-01-91063/14/2016
Dry clutch control is one of the main components of both conventional and advanced automotive powertrain systems. In this paper, a robust control strategy is proposed which is suitable for the precise and accurate control of a clutch-by-wire actuator in automotive applications. A parallel connection of a sliding mode controller to a proportional integral derivative (PID) controller collectively forms the proposed robust controller. The sliding mode controller alone ensures robust control against system nonlinearities by providing a high feedback gain, but it also induces a control chattering phenomenon which could be harmful for the clutch-by-wire actuator. Instead of viewing chattering as an undesirable yet inevitable feature, the chattering signals are used as natural excitation signals for identifying an equivalent PID controller using the recursive least squares algorithm. Analysis is provided on the robustness properties of the control scheme. Simulation results of the proposed controller for a clutch-by-wire actuator are presented using a highly realistic clutch-by-wire system mathematical model. The simulation results demonstrate that the proposed control approach has achieved excellent performance indices while at the same time damp the chattering signal commonly encountered in sliding mode techniques.
Haggag, Salem A.
A New Control Scheme for Automated Manual Transmission with Electromagnetic Powder Clutch2015-24-25479/6/2015
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 Vehicles2015-01-91437/1/2015
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 Nm clutch for a seamless two-speed AMT. The clutch design is based upon Wouterse's model, which is further refined using a Finite Element Analysis (FEA) on the clutch magnetic circuit. A prototype clutch is built and installed inside an existing AMT. The measured clutch coupling torque agrees well with Wouterse's model results, with a maximum error of 6%. The AMT performed seamless gear upshifts on a test bench thanks to the eddy current clutch, which confirms their viability for torque bypass.
Pouliot, Gabriel, Lacerte, Marc-Olivier, Plante, Jean-Sebastien, Micheau, Philippe
A Low Cost System for Active Gear Shift and Clutch Control2015-01-02284/14/2015
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; and, above all, shifting time is less than 20ms. System modeling, regulator design, based on PI-control, and simulation were carried out. Electronics, both signal and power, micro-controller based design and program coding, written in C language, were the next steps. Finally, accurate tests to validate the solution and assess performances were carried out.
Braghin, Francesco, Salis, Francesco
Dry Dual Clutch Transmission (DCT) Thermal Model2015-01-11444/14/2015
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 intended to be used to a) prevent clutch plate over-heating during abusive driving scenarios such as hill holding or multiple GCVW launches in both forward and reverse on grades and b) estimate clutch friction characteristics for control purposes. It is a Simulink based model that is integrated into the transmission controller to notify drivers and take corrective actions in case of overheating. The model also predicts the initial conditions for the temperature of the clutches during engine startups. The thermal model was validated fully in a test cell environment as well as in vehicles using slip ring and telemetry hardware. The thermal model has seven states that include both bell housing air and skin temperatures. Other parameters that affect cooling performance of a dry DCT, such as ambient temperature, and engine coolant and transmission oil temperatures, are also taken into consideration.
Hebbale, Kumaraswamy, Samie, Farzad, Kish, Jonathan
Application of Slope Sensor in Hill-Start to AMT (Automated Manual Transmission) Vehicles2015-01-11084/14/2015
In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock. In addition, it can also avoid backward sliding and engine over-speed effectively. Furthermore, hill-start with low-cost slope sensor and optimal clutch controller can reduce clutch wear, extend the life of dry clutch and improve the drivability.
Chu, Hongqing, Chen, Yong, Guo, Lishu, Gao, Bingzhao, Chen, Hong
A New Clutch Actuation System for Dry DCT2015-01-11184/14/2015
Dry dual clutch transmission (DCT) has played an important role in the high performance applications as well as low-cost market sectors in Asia, with a potential as the future mainstream transmission technology due to its high mechanical efficiency and driving comfort. Control system simplification and cost reduction has been critical in making dry DCT more competitive against other transmission technologies. Specifically, DCT clutch actuation system is a key component with a great potential for cost-saving as well as performance improvement. In this paper, a new motor driven clutch actuator with a force-aid lever has been proposed. A spring is added to assist clutch apply that can effectively reduce the motor size and energy consumption. The goal of this paper is to investigate the feasibility of this new clutch actuator, and the force-aid lever actuator's principle, physical structure design, and validation results are discussed in details. A prototyping of the proposed system is developed for the engagement of the clutch with a position-tracking controller. The advantages of the design and the performance of the control system developed are demonstrated through bench testing. It can be a promising low-cost clutch actuation system for a DCT transmission
Liu, Fengyu, Chen, Li, Yao, Jian, Zhang, Jianlong, Yin, Chengliang, Li, Dongxu, Lee, Chunhao, Huang, Ying
Finite Element Analysis of Transient Thermoelastic Behavior in Multi-Disc Clutches2015-01-06764/14/2015
The high thermal stresses generated between the contacting surfaces of a multi-disc clutch system (pressure plate, clutch discs, plate separators and piston) due to the frictional heating generated during the slipping, is considered to be one of the main reasons of clutch failure for contact surfaces. A finite element technique has been used to study the transient thermoelastic phenomena of a multi-disc dry clutch. The results present the contact pressure distribution, the temperature evaluation and the heat flux generated along the frictional surfaces. Analysis has been completed using two-dimensional axisymmetric model to simulate the multi-disc clutch. ANSYS software has been used to perform the numerical calculation in this paper.
Abdullah, Oday Ibraheem, Abd Al-Sahb, Wassan, Al-Shabibi, Abdullah
A Three Dimensional Finite Element Analysis for Grooved Friction Clutches2015-01-06884/14/2015
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
Model-Based Optimization for an AMT Clutch Control during the Vehicle Starting2015-01-01614/14/2015
With the continuous growth in the emission requirements and higher riding comfort demand, the shift quality becomes more and more an important evaluation index of the automated transmission control algorithms. Traditionally, the shift quality is assessed subjectively by the driver's feeling and then adjusted based on the calibration engineer experience. This classical calibration has disadvantages, such as low reproducibility of the shifting event and a high dependence on the driver's driving habit, so here a model-based multi-objective optimization method is proposed, and the optimization of the clutch control parameters during the vehicle starting is used as an example. Firstly, a Modelica® based vehicle model is introduced. A second-order sliding mode control is applied to track the clutch position trajectory. The clutch engagement point and the clutch engagement speed in the slipping stage are taken as the optimization objects. The shift quality, clutch engagement duration and mean longitudinal jerk during the vehicle starting, are taken as the evaluation criteria. An evolutionary multi-objective optimization method (non-dominated neighbor immune algorithm, NNIA) is chosen to find out the optimal control parameters. Finally the optimal clutch control parameters are determined based on a proposed mathematical function in different accelerator positions, and the testing results show that the optimized clutch control meets the driver's requirements in different conditions.
Huang, Hua, Di, Di, Chu, Yuqiang, Guehmann, Clemens
Launch Performance Optimization of GTDI-DCT Powertrain2015-01-11114/14/2015
A direct trajectory optimization approach is developed to assess the capability of a GTDI-DCT Powertrain, with a Gasoline Turbocharged Direct Injection (GTDI) engine and Dual Clutch Transmission (DCT), to satisfy stringent drivability requirements during launch. The optimization is performed directly on a high fidelity black box powertrain model for which a single simulation of a launch event takes about 8 minutes. To address this challenging problem, an efficient parameterization of the control trajectory using Gaussian kernel functions and a Mesh Adaptive Direct Search optimizer are exploited. The results and observations are reported for the case of clutch torque optimization for launch at normal conditions, at high altitude conditions and at non-zero grade conditions. The results and observations are also presented for the case of simultaneous optimization of multiple actuator trajectories at normal conditions.
Cho, David, Gupta, Rohit, Dai, Edward, McCallum, James, Pietron, Gregory, Shelton, Matthew, Kolmanovsky, Ilya V.
General Motors Front Wheel Drive Seven Speed Dry Dual Clutch Automatic Transmission2015-01-10934/14/2015
General Motors has introduced a new front wheel drive seven speed dry dual clutch automatic transmission in 2014. The 250 Nm input torque rated gear box was designed and engineered for a global market in both front wheel drive and all-wheel drive configurations. The transmission has integrated start/stop capability enabled by the use of an electric motor driven pump and a pressurized accumulator. The architecture selected was chosen for optimization of packaging, fuel economy, mass, shift pleasability, and NVH. High mileage durability and world class drivability were the cornerstone deliverables during the engineering and design process Fuel efficiency is estimated to be 3% - 10% improvement over a conventional six speed automatic transmission. FWD variant wet mass of 78.1 kg was achieved through the rigorous engineering processes used to optimize the transmission system.
Clark, Kirby S., Singh, Tejinder, Buffa, Ronald P., Gayney, Jack M., Cousins, William L., Xie, Zhe, Moorman, Steven P., Wilson, Alexandria, Fannin, Michael P., Graham, Mark L., Preston, Christopher B., Solt, Michael B., Varda, David J., Gilmore, Mark R., Foulkes, Martin G., Risko, Rebecca K.
An Investigation of Heat Generation Due To Friction Using Finite Element Method2014-01-09544/1/2014
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
Experimental Characterization and Modeling of Dry Dual Clutch Wear2014-01-17734/1/2014
Clutch wear is dominantly manifested as the reduction of friction plate thickness. For dry dual clutch with position-controlled electromechanical actuators this affects the accuracy of normal force control because of the increased clutch clearance. In order to compensate for the wear, dry dual clutch is equipped with wear compensation mechanism. The paper presents results of experimental characterization and mathematical modeling of two clutch wear related effects. The first one is the decrease of clutch friction plate thickness (i.e. increase of clutch clearance) which is described using friction material wear rate experimentally characterized using a pin-on-disc type tribometer test rig. The second wear related effect, namely the influence of the clutch wear compensation mechanism activation at various stages of clutch wear on main clutch characteristics, was experimentally characterized using a clutch test rig which incorporates entire clutch with related bell housing. Finally, the previously proposed and experimentally validated physical clutch model, which was focused on the clutch actuator and axial dynamics, is extended to capture both wear related effects as a further step towards a more comprehensive overall clutch dynamics model.
Hoic, Matija, Kranjcevic, Nenad, Herold, Zvonko, Deur, Josko, Ivanovic, Vladimir
Intelligent Energy Management Strategy for a Parallel Hybrid Vehicle2014-01-19094/1/2014
Hybrid electric vehicles (HEV's) are facing increasing challenges in optimizing the energy flow through a vehicle system, in order to improve both fuel economy and vehicle emissions. Energy management of HEV's is a difficult task due to the complexity of the total system in terms of electrical, mechanical and thermal behavior. In this paper, an advanced control strategy for a parallel hybrid vehicle is developed. Four main steps are presented, particularly to achieve a reduction in fuel consumption. The first step is the development of a highly complex HEV model, including dynamic and thermal behavior. Second, a heuristical control strategy is developed to determine the HEV modes and third, a State of Charge (SoC) leveling is developed with the interaction of a fuzzy logic controller. It is proposed to calculate the load point shifting of the Internal Combustion Engine (ICE) and the desired battery SoC. Fourth, novel multi-objective optimization techniques, such as a genetic algorithm, are used for the optimization of the fuzzy logic controller and the heuristical control strategy. The simulation results show a potential fuel reduction relative to the baseline control strategy.
Mustafa, Rashad, Schulze, Mirko, Eilts, Peter, Küçükay, Ferit
Simulation and Analysis Drive Transmission DevelopmentTBMG-172079/1/2013
Vicura is a developer of manual transmissions and dry dual clutch transmissions, as well as powertrain integration in a large number of front wheel drive and all wheel drive applications. The company’s engineers are responsible for a broad range of complex simulation and analysis testing including system, structure, and fluid mechanics. The team performs critical simulation and analysis to ascertain the strength, stiffness, thermal, and dynamic behaviors of all possible transmission assemblies and components (housings, shafts, gears, synchronizers, clutches, etc.).
Dual Mode Control of an Automotive Clutch-By-Wire System2013-01-04844/8/2013
Dry Clutch is one of the main components of both conventional and advanced automotive powertrain systems. Dry Clutch Control has a key role in ride comfort during standing-start and gear-shifting maneuvers. Vehicle shift performance and powertrain torque interruption are of key interest to the control problem. A faster shift time results in a more responsive vehicle but at the same time induces high level of powertrain torque interruption and vise versa. This is due to the high nonlinear behavior of the slip dependent friction torque of the vehicle's dry clutch. In this paper a dual mode control strategy for the dry clutch-by-wire system is proposed. The nonlinear behavior of the clutch friction torque is classified into two regions, a nonlinear region at a low level of clutch slip and a linear region at a high level of clutch slip. The presented control strategy switches between adaptive proportional control in the linear region and sliding mode control in the nonlinear one. The sliding mode control is chosen due to its high level of robustness against system nonlinearity. The proposed control strategy is tested using a highly realistic powertrain model. The simulation results show that the proposed control strategy increases ride comfort by decreasing the powertrain torque interruption that results in that fore-and-aft (jerking) motion which is annoying to vehicle drivers and at the same time ensures acceptable vehicle performance.
Haggag, Salem A., Ibrahim, Fady
Analysis of Thermal Load for Dry Clutch under the Frequent Launching Condition2013-01-08144/8/2013
According to the structural features and working characteristics of the dry clutch, this study focuses on the factors that affect the performance and life of the dry clutch. The temperature rise caused by the clutch slipping was proved as the key factor. Dynamics model of the powertrain for the dry clutch in launching process was established, and friction work generated during the launching process was simulated and calculated. Based on the basic theory of heat transfer, this paper defined the boundary conditions of the temperature field and the finite element model for the dry clutch was built. The transient temperature field of the friction disk, temperature field changes under the frequent starting conditions and the effects of friction material on temperature rise were analyzed, and measures were proposed to reduce the temperature of dry clutch from its design, use and control.
Sun, Shaohua, Lei, Yulong, Fu, Yao, Yang, Cheng, Li, ShunBo
An Approach to Vehicle Brake-By-Wire Optimal Control Tracking Strategy2013-01-06864/8/2013
In this paper, an optimal control tracking strategy for a brake-by-wire system is developed and tested on a laboratory setup consisting of a driving motor, clutch and gearbox system, rotating inertia and an electro-mechanical brake actuator. The presented brake by wire system consists of a brake pedal sub-system connected to the electro-mechanical brake actuator through an electronic control module handling the optimal control logic. A mathematical model of the proposed brake-by-wire control system is presented. The presented mathematical model is simulated and validated against the experimental data. The good agreement between both simulation results and experimental validates the mathematical model. The validated mathematical model is then used to test the proposed optimal control tracking strategy against different levels of disturbances that are difficult to emulate in the laboratory. The developed control logic ensures optimal control effort of the electro-mechanical brake actuator and, at the same time, efficient tracking between the brake pedal command and the braking deceleration profile. Consequently, the introduced logic plays a major role in keeping the tracking between the braking system command and its output as high as possible while not sacrificing the power supply (i.e. high drained electric current) in case of emergency situations. This provides acceptable braking performance while maximizing the system battery life and protects the brake actuator driver against high current.
Haggag, Salem A., Abidou, Diaa
Experimental Characterization and Modeling of Dry Dual Clutch Thermal Expansion Effects2013-01-08184/8/2013
Thermal expansion of a clutch pack with position-controlled actuation can affect the accuracy of clutch normal torque control, because it causes an increase of the clutch normal force for the given actuator position. The paper presents an experimental characterization and mathematical modeling of the dry dual clutch thermal expansion effects. The experimental data have been collected by using a clutch/transmission test rig. The acquired data point to two separate, mutually opposite thermal expansion effects. The first effect relates to increase of the clutch clearance with temperature growth, while the second one includes decrease of press plate and engagement bearing positions for a given clutch torque and a rising temperature (i.e. the clutch torque rises with temperature growth and a constant actuator position). In order to explain and describe these two effects, a geometry analysis of the clutch, focused on thermal expansion, is carried out. Based on the analysis results, a simplified thermal expansion model is developed, extended with temperature dependence of clutch friction coefficient, and experimentally validated.
Hoic, Matija, Herold, Zvonko, Kranjcevic, Nenad, Deur, Josko, Ivanovic, Vladimir
A New Control Strategy of Wet Dual Clutch Transmission (DCT) Clutch and Synchronizer for Seamless Gear Preselect2013-01-03404/8/2013
In this paper, a new gear preselect strategy of wet dual clutch transmission (DCT) is proposed by delaying the gear preselect to the time near the power shift time in order to create a seamless gear preselect. Software in the loop (SiL) method is used to investigate the proposed strategy. High fidelity 13 degree of freedom lumped inertia drivetrain models, i.e., synchronizer model and electro hydraulic model, are constructed and validated using laboratory test data. A closed loop control for electro hydraulic system is developed to control the clutch and synchronizer considering the optimum synchronizer trigger time. Furthermore, the model used in this study is constructed considering the valve spool dynamic in electro hydraulic system and the sleeve dynamic including axial drag force in synchronizer system. The genetic algorithm has been used to obtain the optimum trigger time which is close to the power shift time to sustain uninterrupted torque during gear shifting. A comparison between the conventional sport mode gear preselect strategy with the proposed gear preselect strategy is performed. The obtained results of the proposed strategy show a fuel reduction of 0.8% in New European Driving Cycle (NEDC), within the allowable limits of the shift time.
Adhitya, Mohammad, Mustafa, Rashad, Plötner, Artur, Küçükay, Ferit
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