Browse Topic: Torque converters

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Development of Transmission adaptor for diesel engine application2024-26-033601/16/2024
Transmission adapter is solid, located on cylinder block , on which sits the transmission housing. The function of a flexplate is to provide a mounting point for a torque converter which is used to couple the engine and transmission together when an automatic transmission is used. Transmission adapter provide access for torque convertor and flexplate assembly and protect the flexplate from external environment. Transmission adapter is also support and locate the starter. This study deals with different alloy grade material use, improvement in process to reduce porosity. Porosity observed in first samples of the proposed grade material. The study represents investigation of Transmission adaptor porosity root cause. This also included visual observation, radiography -X ray testing , analysis,3D scan, dimensional inspection, chemical analysis and comparison, tensile testing, truck testing validation tasks. Make sure critical parameter of the clearance meet between flexplate and
Karale, Pranjali
Pseudo Transient Torque Converter Clutch Engagement Process Using Fluid-Structure Interaction Simulation2022-01-078103/29/2022
This investigation utilizes a correlated fluid-structure interaction (FSI) model of the torque converter and clutch assembly to perform a pseudo transient clutch engagement at steady state operating conditions. The pseudo transient condition consists of a series of nine steady state simulations that transition the torque converter clutch from fully released to near full lockup at a constant input torque and output speed representative of a highway cruising speed. The flow and pressured field of the torque converter torus and clutch are solved using a CFD model and then passed along to a transient structural model to determine the torque capacity of the lockup clutch. Bulk property assumptions regarding the friction material, deformation of the clutch plate and deflection of supporting structures were made to simplify the model setup, run time and solution convergence. Telemetry pressure measurements acquired in an operating torque converter under similar operating conditions on a
Beldar, Aniket, Robinette, Darrell, Blough, Jason
Vehicle surge reduction technology during towing in parallel HEV pickup trucks2022-01-073303/29/2022
In order to ensure the comfort of the parallel HEV pickup truck, this report proposes a vehicle surge reduction technology during towing that utilizes a motor and shifting. Hybridization is one of the approaches to reduce fuel consumption toward the realization of carbon neutrality. The parallel HEV is more advantageous to high-load operation such as towing and loading, which are often used in pickup trucks than the series parallel HEV represented by the Toyota Hybrid System. Since the parallel HEV has an engine, motor, torque converter, and transmission connected in series, a vehicle surge may occur when engaging the lockup clutch due to fuel efficiency and drivability needs, as with conventional powertrains. Vehicle surge is a low-frequency vibration phenomenon. In general, the applied force is the torque fluctuation caused by the engine and tires, and the amplification is the driveline torsional first-order resonance, suspension resonance, and cabin resonance. The vibration is more
Okaya, Shingo, Kokaji, Jun, Quinteros, Luis, Hasegawa, Yoshio, Masunaga, Seiji
Normally Locked Torque Converter as an Alternative Mutli-speed Transmission for Electric Vehicles2022-01-077503/29/2022
An emerging trend in electric vehicle (EV) propulsion system engineering is the proposal of a wide range of two-speed transmission to improve performance, energy consumption and potentially alter electric motor characteristics. This paper proposes the design and integration of a torque converter and clutch-damper assembly that is normally locked as an alternative means of achieving a two-speed transmission for EV drive units. The layout of the drive unit with the torque converter is included along with an overview of the hydraulic system and control strategy to minimize energy consumption. The performance attributes required to match the torque converter to an electric motor verse an internal combustion engine are reviewed in the context of achieve comparable performance to a two speed transmission tractive effort. Dynamometer testing of a torque converter in both rotational directions is provided to highlight the preferred method of operation during reverse operation of the drive unit
Robinette, Darrell
Wheel Torque-based Control: Transmission Input Torque Determination and Inertia Compensation2022-01-089703/29/2022
Traditionally, production vehicles have interpreted the driver pedal request as a transmission input torque demand. However, with the advent of electrified vehicles, where actuators are located at different positions in the drivetrain, and of autonomous vehicles, which are self-driving, there is a requirement to interpret the demand (either human or virtual) in the vehicle acceleration domain. To address this requirement, we develop a Wheel Torque-based longitudinal Control (WTC) framework, wherein the desired vehicle acceleration is first expressed as a wheel torque demand and then transformed into each actuator’s torque domain. For powertrains with a step-ratio transmission and a torque converter (TC), a key challenge of the WTC framework is the determination of the torque request in the transmission input domain, especially during open or slipping TC operation. This determination needs to take into account the Inertia Compensation Torque (ICT), i.e., the torque required to spin up
Roy, Judhajit, Ravichandran, Maruthi, Meyer, Jason, Zhao, Yanan
Toyota’s New Hybrid Unit “L4A0” 2022-01-079503/29/2022
Toyota developed a new hybrid unit “L4A0” for the new Tundra, which creates both good drivability and environmental performance. To ensure off-road, towing performance and typically truck driving characteristics, the unit is based on a transmission with a torque converter and multi-plate lock up clutch, and installing a motor and K0 clutch between the engine and transmission. The motor and K0 clutch are built into a module, making it possible to create new hybrid units by combining the module with various transmissions. The unit features many different motor controls. For example, in the case of step-in acceleration input, typically to achieve the desired output torque, a kick-down shift is necessary; however, utilizing “L4A0” both high response and high power output is realized without a kick-down shift. This is accomplished by assisting the engine with the motor during engine torque delay at low engine revolutions. Simultaneously, this contributed to better fuel economy by allowing
Tan, Guodong, Ikemura, Masashi, Hasegawa, Yoshio, Ohki, Takao, Baba, Masayuki, Nakamura, Atsuro, Herring, Craig, Niinomi, Atsushi, Hamano, Makoto, Mizoguchi, Yasuhiro
Assessing the effect of torque converter losses on the start emission and Engine stability in TGDI AT Vehicle2021-28-018510/01/2021
The emission norms around the world are continuously changing and getting stringent with every revision. India is on its way to make its emission norms at par with that prevailing in the developed nations. The cold-start condition is an important factor affecting vehicle emissions from gasoline direct injection (GDI) and port fuel injection (PFI) engines. In this paper, the effects of change in torque converter losses on emissions are experimentally investigated in a TGDI AT vehicle. The instant engagement of the torque converter puts a sudden torque on the engine and thus affects its stability. Thus, to overcome the stability issue, Engine torque has to be simultaneously increased for smooth engagement. As a result, the likelihood of the slightly leaner air-fuel mixture in the cylinder, which results in higher Nox formation, is much greater in an AT vehicle than that of a similar MT vehicle. Additionally, the temporary ineffectiveness of motor vehicle emission controls at startup
RAI, ABHISHEK, SARAN KUMAR REDDY, KETHIREDDY, SOMANI, KAPIL
Vibration Mitigation of Dynamic Skip Fire Engines with Flywheel Optimization and Torque Converter Clutch Slip2021-01-110508/31/2021
Dynamic Skip Fire (DSF) is an advanced cylinder deactivation technology to reduce fuel consumption and emissions of internal combustion engines. The firing sequence may vary dynamically depending on driver demanded torque with all cylinders capable of deactivation. This creates a challenge for managing noise vibration and harshness (NVH) caused by the low frequency excitation in the engine’s torque profile, especially in smaller engines with 3 or 4 cylinders. Due to the varying nature of firing sequences, the excitation is not limited to one or two engine orders and can vary with time, requiring broadband mitigation of the driveline. This work proposes the optimization of flywheel inertia combined with careful control of torque converter slip to overcome this challenge. Four different flywheel configurations and varying levels of torque converter slip were tested on a VW Jetta fitted with a 1.8L 4-cylinder engine with DSF control capability. For each configuration, DSF flyzone maps
Srinivasan, Vijay, Arvanitis, Anastasios
Torque Limiters 101: Benefits, Types, and ComparisonsTBMG-3783710/01/2020
Modern machines can be simple — a single element translating a rotary-to-linear motion. They can also be complex — a collection of interacting mechanisms operating in a multi-dimensional plane. The commonality of these mechanisms is the element of motion that is predictable with a known torque or force and velocity.
A Reverse Engineering Method for Powertrain Parameters Characterization Applied to a P2 Plug-In Hybrid Electric Vehicle with Automatic Transmission2020-37-002106/23/2020
Over the next decade, CO2 legislation will be more demanding and the automotive industry has seen in vehicle electrification a possible solution. This has led to an increasing need for advanced powertrain systems and systematic model-based control approaches, along with additional complexity. This represents a serious challenge for all the OEMs. This paper describes a novel reverse engineering methodology developed to estimate relevant but unknown powertrain data required for fuel consumption-oriented hybrid electric vehicle modelling. The main estimated quantities include high-voltage battery internal resistance, electric motor and transmission efficiency maps, torque converter and lock-up clutch operating maps, internal combustion engine and electric motor mass moment of inertia, and finally front/rear brake torque distribution. This activity introduces a list of limited and dedicated experimental tests, carried out both on road and on a chassis dynamometer, aiming at powertrain
Galvagno, Enrico, Millo, Federico, DiPierro, Giuseppe, Velardocchia, Mauro, Perazzo, Alessandro, Mari, Gianluca
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
Quantifying Engine Braking for Various Common Street Motorcycles2020-01-088004/14/2020
Motorcycle engine braking was measured in each forward gear for a cross-section of typical street motorcycles. Using GPS data acquisition and video, deceleration relative to speed was examined. Motorcycle characteristics included various engine displacements and types of motorcycle. The data acquired will give more insight into the extent which engine braking is a factor for deceleration, a topic which has not been addressed in a peer-reviewed journal article to this date.
Jansen, Henricus, LeBlanc, Beau, Wilhelm, Christopher, Shaw, Tyler, Lowi, Alvin
An LQR Approach of Automatic Transmission Upshift Control Including Use of Off-Going Clutch within Inertia Phase2020-01-097004/14/2020
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
Cvok, Ivan, Deur, Josko, Ivanovic, Vladimir, Zhang, Yijing, Fujii, Yuji
Testing of a wet plate clutch system for anti-shudder performance2020-01-056004/14/2020
The wet clutch system ( WCS ) is a complex combination of friction plates, separator plates and lubricant. The basic function of the WCS is to transfer torque under various operating conditions such as slipping, shifting, start/launch and/or torque converter clutch operation. During these conditions the slope of the coefficient of friction versus slip speed ( µ-V ) curve must be positive to prevent shudder of the WCS. A test procedure is needed to evaluate the WCS over a durability duty cycle to monitor the µ-V curve slope and shudder potential. The clutch plates and fluid must be tested together and remain together during the test to evaluate as a WCS. The objective of this paper is to describe this new test procedure which builds on the basics of the SAE J2964 - Low Speed Continuous Slip µ-PVT test procedure but a duty cycle is added to age the WCS. The test includes measurement of the µ-V slope at several intervals during the test ( before break in, after break in, and after each 12
Diemer, Larry, Bares, Jason, Greening, Brent, Ezanno, Philippe, Whitticar, David, Klotchikhine, Vladimir, Greening, Charles
Launch and Lock with Multi-input Multi-Output Converter Control2020-01-026204/14/2020
A torque converter is a type of fluid coupling device used to transfer engine power to the gearbox and driveline. A bypass clutch equipped in a torque converter assembly is a friction element which when fully engaged, can directly connect the engine to the gearbox. The torque converter is an important launch device in an automatic transmission which decouples engine speed from gearbox input speed while provides torque multiplication to drive the vehicle. During partial pedal launch, it is desired to engage the bypass clutch early and reduce the converter slippage in order to reduce power loss and achieve better fuel economy. However, engaging the bypass clutch early and aggressively may disturb the wheel torque and cause an unpleasant driving experience. This paper describes a multi-input multi-output (MIMO) control method to coordinate both engine and converter bypass clutch to simultaneously deliver desired wheel torque and reduce converter slippage. This control method leverages a
Xu, Yang, Chen, Weitian, Ford, Stuart, Liu, Pinzhi, Dai, Edward, Keller, Bret, Jiang, Hong
A Study on the Development of the CPA (Centrifugal Pendulum Absorber) Reducing the Rattle & Booming Noise in the Manual Transmission Vehicle2020-01-039704/14/2020
In recent years, the automotive engine strategies are forced on downsizing and down speeding to enhance fuel economy and reduce the emission. These make torque increase significantly in order to improve the vehicle performance, especially in diesel engines. At this time, the torsional damper performs the most important role in the driveline NVH of the manual transmission system. The clutch disk with torsional dampers is not easy to be applicable to the high torque of low speed RPM range. And* DMF with sufficient isolation of vibrations of driving system includes disadvantages of the expensive cost, delayed response, and engine NVH aspect deteriorated due to increase of angular acceleration of engine. This paper presents that the Centrifugal Pendulum Absorber (CPA) is applied to maximize the isolation and to compensate for the disadvantages of DMF and SMF system. Furthermore, CPA was developed for the first time in the world on SMF clutch discs in manual transmission.
Kim, Ukjin
An Iterative Method to Determine Clutch Clearances in Torque Converters by Integrating the Fluid and Structure Analyses2020-01-093604/14/2020
Determining an amount of clutch clearance for the lockup device in a torque converter is important for its being operating precisely in the intended mode. Challenges may exist for the torque converters whose nominal clearances are on purpose very small. Any potential changes in the clutch lockup system (e.g., due to the deformation of components) may make such a small clearance instantaneously diminish during the mode of open-clutch, thus leading to unwanted drag in the clutch and unnecessary loss of energy. In the open-clutch mode, the actual clutch clearance may be different from the nominal clearance anticipated, primarily because of deformation caused by the internal load acting on clutch members. It has been found that the pressure distribution in a clutch chamber also depends on the very clutch gap through which the fluid flows. This interdependence between the fluid pressure load and structural deformation is typical of two-way coupling in simulation. As an alternative approach
Yang, Zane, Jeyabalan, Subramanian, Khajamohideen, Abdur-Rasik, Solaimalai, Maheshkannan, Rajendhran, Dhashnakumar
Mathematical Analysis of Clutch Thermal Energy during Automatic Shifting Coupled with Input Torque Truncation2020-01-096704/14/2020
A step-ratio automatic transmission alters torque paths for gearshifting through engagement and disengagement of clutches. It enables torque sources to run efficiently while meeting driver demand. Yet, clutch thermal energy during gearshifting is one of the contributors to the overall fuel loss. In order to optimize drivetrain control strategy, including the frequency of shifts, it is important to understand the cost of shift itself. In a power-on upshift, clutch thermal energy is primarily dissipated during inertia phase. The interaction between multiple clutches, coupled with input torque truncation, makes the decomposition of overall energy loss less obvious. This paper systematically presents the mathematical analysis of clutch thermal energy during the inertia phase of a typical single-transition gearshift. In practice, a quicker shift is generally favored, partly because the amount of energy loss is considered smaller. However, the analysis reveals that there is a critical input
Zhang, Yijing, Fujii, Yuji, Hippalgaonkar, Rohit, Cvok, Ivan, Ivanovic, Vladimir, Deur, Josko, Ranogajec, Vanja
A Simulation Study of Rotating Impact within a Damper of Torque Converter2020-01-050004/14/2020
It is common that angular velocities can be different from time to time between an engine output and transmission input, because both are connected by a damper in torque converter with flexible elements in it. When this difference occurs abruptly for some reasons, an internal impact could start between the engine-attached members (also known as driving members) and the transmission-attached members (or driven members). The resulting impact load could be several times the torque an engine’s combustion force can generate, depending on the impact energy. An impact load can be very devastating to a torque converter and other power-train members, just as to all other mechanical systems. This work presents a comprehensive and interesting study to help understand the rotational impact behavior for a system where none of bodies is stationary at the onset of impact. Using an explicit finite-element solver for case studies, the author will assess what role a friction-based clutch, placed between
Yang, Zane
Inside Tremec's SUPERCAR DCT20AUTP02_0401/01/2020
To polish the 2020 mid-engine Corvette's driving prowess, GM and Tremec engineers joined forces to create a new and better automated transaxle. Explaining Corvette's move to one transmission for all buyers, global chief engineer Tadge Juechter notes, “Our customers began requesting a dual-clutch automatic transmission [DCT] several years ago. Following the introduction of the C7 Corvette in 2014, our take-rate for sticks [manual gearboxes] fell from 50 percent to less than 20 percent this year.” Searching the globe - read Europe - for a suitable DCT, Juechter's team found none with sufficient torque capacity to survive behind the lively LT2 6.2-L V8 planned for the all-new 2020 mid-engine edition of GM's reimagined sports car. To solve that dilemma, discussions began with Tremec, the Mexico City-based manufacturer which has supplied GM, Ford and FCA with manual transmissions for two decades. While Tremec had the expertise to make the mechanical components packed inside a dual-clutch
Sherman, Don
Hydrodynamic Drives TerminologyJ641_201912 (Current)12/02/2019
Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. EXAMPLE: Two systems of blade angle designations are described. Consequently, when a blade angle is specified, the system should be designated. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.
Automatic Transmission and Transaxle Committee
Fuel Efficiency Improvement in Automatic Transmissions by Lockup Slip Methodology2019-28-002910/11/2019
Increasing of automatic transmissions in passenger cars is based on pleasure of driving, smooth acceleration and easy operation makes the customer satisfaction. Challenges beyond 2020 is BS VI emission norms in India - a very tough goals on CO2& NOx reduction in Gasoline & Diesel vehicles. But its setback in lower fuel economy. To support & enhance fuel economy in Automatic transmissions as part of drivetrain technologies, this article discusses about the power losses in torque converters and experiments on the actual Automatic transmission (AT) vehicle on-road to understand the real city driving behavior in the aspects of gear utilization & gas pedal utilization throughout the entire traffic conditions. With that data research, slip area and slipping conditions is determined & clutch slip control is enabled at area in torque converter by ensuring that NVH parameters are not affected. The addition of the Lock-up Slip system add value in terms of “Joy of Driving” by providing a 2-3
Sukumar, Arun
Domestic Performance Torque Converter ManufacturingJ2440_201910 (Current)10/09/2019
The scope of this SAE Draft Technical Report is to establish dimensional standards for high-performance domestic torque converter manufacturers. Many torque converter manufacturers build converters to their own standards. Some of these standards may be outside of the specifications that define a quality performance torque converter.
Motor Vehicle Council
Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs2019-01-145506/05/2019
The recent automotive industry trend towards electrification has created new challenges for NVH engineers. These challenges stem from new powertrain architectures and their complex interactions, the governing control strategies which aim to optimize energy management, and new unmasked sources of excitation. Additionally, vehicle manufacturers are attempting to reduce hardware testing in order to rapidly satisfy increasing production demand and to minimize its costs. Hence, to meet the above-mentioned challenges up front in the development process of Hybrid Electrical Vehicles (HEVs) while balancing competing design objectives of drivability, durability and NVH, a simulation-led design and optimization is required. NVH problems are often the result of mechanisms that originate through complex interactions between different physical domains (flow, electromagnetic, structural/mechanical, control logic, etc.) and the assembly of individual components into a complete system. Therefore
Gomez, Llorenc Foraste, Zeman, Jonathan, Liu, Jack
Testing Methods and Signal Processing Strategies for Automatic Transmission Transient Multiplexed Pressure Data2019-01-150006/05/2019
Transmissions have multiple transient events that occur from gear shifting to torque converter clutch application. These transients can be difficult to capture and observe. A six speed front wheeled drive transmission was instrumented with pressure transducers to measure clutches and the torque converter. Due to size restrictions internal to the torque converter the data had to be multiplexed across three different transmitters. A method to capture a transient event through the use of multiplexed data was developed to create a data set with the transient event occurring on each channel. Once testing is completed, the data has to be split into individual channels and synced with the operational data. The data then can be used in both time and frequency domain analysis. It is important to understand that the data is not continuous and must be taken into consideration when post processing it for further results.
Woodland, Mark, Blough, Jason, Robinette, Darrell, Anderson, Carl, Frait, Steve, Devendran, Ram Sudarsan
Systematic CFD Parameter Approach to Improve Torque Converter Simulation06-12-02-000804/08/2019
A systematic parametrization approach was employed to simulate a torque converter operating over a wide range of speed ratios. Results of the simulation yielded torque converter impeller and turbine torques prediction errors below 11% when compared to manufacturer data. Further improvements in the computational fluids dynamic (CFD) model reduced such errors down to 3% for the impeller and 6% for the turbine torque predictions. Convergence was reached well under 300 iterations for the most optimal variable setting, but each speed ratio was let to run for 300 iterations. Solution time for the 300 iterations was 40 minutes per speed ratio. The systematic parametrization provides a very competitive procedure for torque converter simulation with reduced computational error and fast solution time.
De Jesus Rivera, Edward, Robinette, Darrell L., Blough, Jason R., Anderson, Carl L., Frait, Steve
In-Gear Slip Control Strategy of Dry-Clutch Systems Using a Sliding Mode Control2019-01-130504/02/2019
This paper proposes a clutch control strategy during in-gear driving situations for Dual Clutch Transmissions (DCTs). The clutch is intentionally controlled to make small amount of a slip to identify the torque transfer capacity. The control objective of this phase is to ensure the clutch slip fairly remaining the specified value. To achieve this, the micro-slip controller is designed based on sliding mode control theory. Experimental verifications performed on onboard control system of the DCT equipped vehicle demonstrate that the proposed controller good tracking performance of the desired slip speed.
Kim, Jinsung, Nam, Juhyun
Quantifying the Effect of Initialization Errors for Enabling Accurate Online Drivetrain Simulations2019-01-034704/02/2019
Simulations conducted on-board in a vehicle control module can offer valuable information to control strategies. Continued improvements to on-board computing hardware make online simulations of complex dynamic systems such as drivetrains within reach. This capability enables predictions of the system response to various control actions and disturbances. Implementation of online simulations requires model initialization that is consistent with the physical drivetrain state. However, sensor signals and estimated variables are susceptible to errors, compromising the accuracy of the initialization and any future state predictions as the simulation proceeds through the numerical integration process. This paper describes a drivetrain modeling and analysis method that accounts for initialization errors, thereby enabling accurate simulations of system behaviors. First, the hybrid dynamical system paradigm is employed to develop a torsional drivetrain model that captures the dynamics during a
Yang, Hang, Kidambi, Narayanan, Wang, Kon-Well, Pietron, Gregory M., Hippalgaonkar, Rohit, Fujii, Yuji
Coordinated Mode Transition Control for a Novel Compound Power-Split Hybrid Electric Vehicle2019-01-130604/02/2019
Because of the direct connection between the compound power split hybrid transmission (CPSHT) and the engine in hybrid electric vehicle (HEV), engine ripple torque (ERT) can lead to obvious jerks when the mode transition from electric driving mode to hybrid driving mode occurs. In order to enhance the riding comfort, two additional wet clutches are mounted in this novel CPSHT and the relevant coordinated control strategy is developed. Firstly, after the description of the mechanical and hydraulic parts of the novel CPSHT, the dynamic plant model including driveline model, engine ripple torque and clutch torque is deduced. Secondly, the mode transition process in the original and current designs are compared and analyzed with the equivalent level diagram and the encountered problems are stated. Thirdly, a coordinated control strategy is designed to determine the target motor torque, clutch torque, engine torque, and the moment of fuel injection based on the second-order sliding mode
Shen, Dengfeng, Guehmann, Clemens, Zhang, Tong
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
Ford engineers a tech barrage with 2020 Lincoln Aviator19AUTP01_1601/01/2019
Ford Motor Co. officially launched its 2020 Lincoln Aviator at the 2018 Los Angeles auto show, with the all-new three-row midsized luxury SUV featuring a barrage of equally new and significant technologies. Production is slated for 3Q 2019 at Ford's Chicago assembly complex. Aviator debuts Ford's first RWD/AWD vehicle platform, coded CD6, that was engineered from a clean sheet to support both conventional gasoline-ICE and plug-in hybrid models. It also features the much-anticipated electrified variant of Ford's 10R 10-speed automatic transmission, which will also be used to “hybridize” the F-Series pickup. Known internally as MHT (modular hybrid transmission), the electrified 10R packages the e-motor on the input side, between the engine and gearset. It retains its torque converter. Non-hybrid Aviators will use the conventional 10R60 unit.
Brooke, Lindsay
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
Interior Noise Refinement in an ICV Bus through Driveline Torsional Vibration Analysis2018-01-147206/13/2018
With a push for urbanization across cities, there is an increased demand for mobility in public transportation especially buses which are provided through state transport undertakings. Hence, the expectations of this class of vehicles will be high in terms of quality and comfort to the passengers. The noise inside the passenger area of the bus becomes an important parameter, which sets apart a bus manufacturer from its competitors. The driveline of the bus is the system responsible for the transfer of power from engine to the wheels. The noise and vibration problems associated with it are detected only in the late stages of the design chain, when all its elements are tested together over a wide range of conditions. Since, calibration of engine and the selection of transmission is freezed in early stages, satisfying power and torque requirements, the only viable option left to address the problem is by optimizing the clutch parameters. Combustion in multi-cylinder four stroke diesel
Kamani, Keval, Kannan, P, P, Sivaraman
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
Travelling Resistance Estimation and Sandy Road Identification for SUVs2018-01-057804/03/2018
The mechanical properties of sandy road are quite different from those of hard surface road. For vehicle control systems such as EMS (engine management system), TCU (transmission control unit) and ABS (antilock brake system), the strategies and parameters set for solid surface road are not optimal for driving on sandy road. It is an effective way to improve the mobility of all-terrain vehicles by identifying sandy road online and shifting the control strategies and parameters of control systems to sandy sets. In this paper, a sandy road identification algorithm for SUVs is proposed. Firstly, the vehicle signals, such as engine torque and speed, gear position, wheel and vehicle speed, are acquired from EMS, TCU and ESP (electronic stability program) through CAN (controller area network) bus respectively. Based on the information and longitudinal force equilibrium equation, the travelling resistance of vehicle is estimated. The hydraulic torque converter is divided into several parts to
Wu, Weixiang, Zhang, Jian, Zhao, Jian, Zhu, Bing
Classification of Time Series Measurement Data for Lock-Up Clutch of Automatic Transmission of Vehicles Using Deep Convolutional Neural Networks2018-01-039904/03/2018
A newly developed classifying method for time series measurement data of automatic transmission of vehicles is presented. The proposed method uses deep convolutional neural networks to learn what is comfortable acceleration. In addition, our proposal method employs supervised learning based on experienced engineer’s criterion. As a demonstrative problem, we consider the classification of time series measurement data for lock-up clutch control of an 8 speed automatic transmission.
Kawakami, Takefumi, Ide, Takanori, Tomita, Kiyohisa, Moriyama, Eiji, Tsutsui, Hiroshi, Hoki, Kunihito, Muramatsu, Masakazu
General Motors Hydra-Matic 9T50 Automatic Transaxle2018-01-039104/03/2018
General Motors Global Propulsion Systems’ first nine-speed automatic transmission makes its debut in the 2017 Chevrolet Malibu, advancing a legacy of multispeed transmissions designed to optimize efficiency, performance and refinement. The Hydra-Matic 9T50 nine-speed is paired with a Ecotech 2.0L Turbo engine in the Malibu, contributing to an EPA estimated 33 mpg highway, a three-percent increase over the 2016 Malibu with an eight-speed automatic paired to the same engine. The 9T50 has a wider 7.6:1 overall ratio, which is the ratio between the first gear ratio and the top gear ratio, - compared to the six-speed’s 6.0:1 ratio. The 9T50 is fitted with a “deep” 4.69 first gear ratio for excellent off-the-line acceleration and a “tall” 0.62 top gear ratio for low-rpm highway cruising. That balance optimizes acceleration and fuel economy while reducing engine noise during cruising. With nine available forward ratios, the step size between the gears is reduced providing smooth, precise
Martin, Thomas, Hendrickson, James
WHAT WE'RE DRIVING18AUTP02_1502/01/2018
It isn't every carmaker that introduces its new model with a session on a tight and slippery test track. But when it's a 1955-kg (4090-lb) sedan with 450 kW (603 hp) and 850 N·m (627 lb·ft) available at the shove of a foot, it is a useful education. That's what Mercedes-Benz offers its U.K. buyers of the new Mercedes-AMG E 63 S 4Matic+.
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
Driveline Ratio Selection and Shift Map Optimization for Automatic Transmission Vehicle at Concept Phase through Simulations06-11-01-000510/08/2017
Traditionally driveline ratios are selected based on trial and error method of proto vehicle testing. This consumes lot of time and increases overall vehicle development effort. Over last few decades, simulation-based design approach has been extensively used to alleviate this problem. This paper describes torque converter and final drive ratio (FDR) selection at concept phase for new Automatic Transmission (AT) vehicle development. Most of the critical data required for simulating vehicle performance and fuel economy (FE) targets were not available (e.g. shift map, clutch slip map, pedal map, dynamic torque, coast down, etc.) at an initial stage of the project. Hence, the risk for assuming right inputs and properly selecting FDR/Torque converter was particularly high. Therefore, a validated AVL Cruise simulation model based on an existing AT vehicle was used as a base for new AT vehicle development to mitigate the risk due to non-availability of inputs. The simulation model shows 97
Paulraj, Srinivasan, Muthiah, Saravanan
Machine Vision SystemTBMG-2730408/01/2017
A number of instruments have been built to obtain range images — a two-dimensional array of numbers that gives the depth of a scene along many directions from a central point in the instrument. Instead of measuring the brightness of many points in a scene, as in a television camera, these instruments measure where each point is in a three-dimensional space. Both range images and the more conventional intensity images from digital cameras have been used in the computer vision research community to determine the pose of observed objects or surface shapes. “Pose” refers to a complete description of an object's position and orientation. For a rigid object, this requires six numbers — such as X, Y, Z, pitch, yaw, and roll — or six equivalent coordinates. The previous methods for pose estimation all suffer from either a lack of generality or from time inefficiency.
Impact of the Future Fuel Economy Targets on Powertrain, Driveline and Vehicle NVH Development2017-01-177706/05/2017
The automotive industry continues to develop new technologies aimed at reducing overall vehicle level fuel consumption. Powertrain and driveline related technologies will play a key role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. Specifically, use of technologies such as downsized engines, idle start-stop systems, aggressive torque converter lock-up schedules, wide-ratio spread transmissions, and electrified propulsion systems are vital towards meeting aggressive fuel economy targets. Judicious combinations of such powertrain and driveline technology packages in conjunction with measures such as the use of low rolling resistance tires and vehicle lightweighting will be required to meet future OEM fleet CO2 targets. Many of the technologies needed for meeting the fuel economy and CO2 targets come with unique NVH challenges. In order to ensure customer acceptance of new vehicles, it is imperative that these NVH challenges be understood and solved. This paper
Wellmann, Thomas, Govindswamy, Kiran, Tomazic, Dean
New RWD 10 Speed Automatic Transmission for Passenger Vehicles2017-01-109703/28/2017
Aisin AW (AW) and Toyota Motor Corporation (TMC) have developed a new rear wheel drive (RWD) 10-speed automatic transmission, AWR10L65 (TMC name: AGA0), suitable for RWD/AWD luxury passenger cars and sports cars. This 10-speed automatic transmission provides enhanced drivability leading to outstanding driver satisfaction. This has been accomplished using a close ratio gear train with optimized gear steps for rhythmic shift changes and quick acceleration. Low rpm lock-up and highly responsive shift changes result in a direct shift feel. This automatic transmission contributes to improved fuel economy by having higher efficiency and lower mass than current 8-speed RWD automatic transmissions.
Suzuki, Tomohide, Sugiura, Hiroyuki, Niinomi, Atsushi, Maezuka, Shingo, Miyazaki, Terufumi, Habata, Yohei
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
Regenerative Braking Control Development for P2 Parallel Hybrid Electric Vehicles2017-01-114903/28/2017
Regenerative braking in hybrid electric vehicles is an essential feature to achieve the maximum fuel economy benefit of hybridization. During vehicle braking, the regenerative braking recuperates its kinetic energy, otherwise dissipated into heat due to friction brake, into electrical energy to charge the battery. The recuperation is realized by the driven wheels propelling, through the drivetrain, the electric motor as a generator to provide braking while generating electricity. “Rigid” connection between the driven wheels and the motor is critical to regenerative braking; otherwise the motor could drive the input of the transmission to a halt or even rotating in reverse direction, resulting in no hydraulic pressure for transmission controls due to the loss of transmission mechanical oil pump flow. Because of the potential open or slipping torque converter and the multiple step ratios in the drivetrain, and the gear shifting transients in P2 parallel hybrid electric vehicles, special
Zhao, Yanan, Kuang, Ming, Nefcy, Bernard, Colvin, Dan, Ford, Stuart, Liu, Zheng
Numerical Investigation of Jet-Wake and Secondary Flows in a Hydrodynamic Torque Converter2017-01-133503/28/2017
Jet-wake flow and secondary flows are undesirable in torque converters as they are responsible for flow losses and flow nonuniformity; that is, jet-wake flow and secondary flows negatively affect the torque converter performance. Therefore, it is very important to investigate and minimize the undesirable flows to decrease flow losses in torque converter. However, the existing studies are limited to employ geometry design parameter modifications rather than focusing on the actual causes and intrinsic physical mechanism that generate the flows to reduce the flow losses. In this paper, Calculation model of a torque converter is presented first and a three dimensional CFD code was used to simulate the internal flow field of a torque converter. The simulation results coincide with experimental measurements, which verifies the validity of the method. Based on flow field calculation results, the internal flow field of impeller, turbine and stator were analyzed, respectively. The rothalpy
Chen, Jie, Wu, Guangqiang
Driveability Improvement with Innovative Toyota 8 Speed Automatic Transmission Control2017-01-110903/28/2017
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 Compact Torque Converter with New Multiple Disk Clutch for Toyota New FWD Eight-Speed Transmission Direct Shift-8AT2017-01-111803/28/2017
Increasingly stringent environmental regulations requiring lower CO2 emissions and higher fuel economy have made it essential to develop vehicles with superior fuel efficiency and cleaner emissions. At the same time, there is growing demand for even more powerful and quieter vehicles. To help satisfy these requirements, Toyota Motor Corporation has developed a new 8-speed automatic transmission for front wheel drive vehicles, incorporating its first compact torque converter with a multiple disk lock-up mechanism. This newly developed compact torque converter with a multiple disk lock-up mechanism was designed under the Toyota New Global Architecture (TNGA) development concept to achieve an excellent balance between higher efficiency through the commonization of components and stronger product appeal through installation on a whole family of transmissions. This compact torque converter is compatible with a variety of engines from inline 4-cylinder to V6 configurations. This transmission
Hachisuwa, Isamu, Kato, Naoki, Kusamoto, Daisuke, Miyata, Hideki, Okada, Takuya, matsunaga, Hitoshi, Kuroyanagi, Takamitsu, nakazuru, Makoto
Numerical Investigation of Flow Induced Excitations in a Torque Converter2017-01-111503/28/2017
This study analyzes the flow dynamics of a fluid within an operating torque converter. Transient computational fluid dynamics (CFD) simulations have been carried out with prescribed torque converter motions using commercially available CFD software. The analysis computes torque converter excitation forces that predict flow induced excitations during converter operation. In this study, various torque converter designs are compared and assessed with the aim of limiting flow induced excitations.
Sawkar, Nandan A., Modi, Prashant, Fingerman, Michael
Toyota New TNGA High-Efficiency Eight-Speed Automatic Transmission Direct Shift-8AT for FWD Vehicles2017-01-109303/28/2017
The new eight-speed automatic transmission direct shift-8AT (UA80) is the first automatic transmission to be developed based on the Toyota New Global Architecture (TNGA) design philosophy. Commonizing or optimizing the main components of the UA80 enables compatibility with a wide torque range, including both inline 4-cylinder and V6 engines, while shortening development terms and minimizing investment. Additionally, it has superior packaging performance by optimizing the transmission size and arrangement achieving a low gravity center. It contributes to Vehicle’s attractiveness by improving driving performance and NVH. At the same time, it drastically improves fuel economy and quietness.
Michikoshi, Yosuke, Kusamoto, Daisuke, Ota, Hirofumi, Ikemura, Masashi, Takebayashi, Noritaka, Nobukazu, Ike, Takashi, Yasuda, Ryohei, Inoue
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