Browse Topic: Automatic transmissions

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SAE No. 2 Friction Test Machine µPVT TestJ2490_202511 (Current)11/25/2025
This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.The specific purpose of this document is to define a µPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users.The only variables selected by the supplier or user of the friction system are:a. Friction materialb. Fluidc. Reaction platesThese three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document.This procedure is intended to evaluate the endpoint/midpoint ratios, midpoint and breakaway coefficients. The procedure can be used to demonstrate changes that occur between the different levels of engagement speed, sump temperature, and apply pressure. Refer to SAE J2487, SAE J2488, or SAE J2489 for coefficient variations due to changes in power level.The procedure, as described in detail in Table 1, consists of four 50 cycle break-in levels at 3500 rpm with increasing steps of apply pressure, followed by 16 levels consisting of 25 dynamic engagements, and one breakaway following completion of the 25th dynamic cycle. The 16 levels are achieved by varying initial engagement speed, apply pressure, and oil sump temperature while the inertia is kept constant at 0.701 kg/m2.
Automatic Transmission and Transaxle Committee
SAE No. 2 Friction Test Machine 6000 rpm Stepped Power TestJ2488_202511 (Current)11/25/2025
This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.The specific purpose of this document is to define a 6000 rpm stepped power test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 6000 rpm and is intended as a standard procedure for common use by both suppliers and end users.The only variables selected by the supplier or user of the friction system are:a. Friction materialb. Fluidc. Reaction platesThese three variables must be clearly identified when reporting the results of using this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document.This procedure is not intended to evaluate the initial coefficient or break-in characteristics. For this information, refer to SAE J2490 SAE No. 2 Friction Test Machine PVT test.
Automatic Transmission and Transaxle Committee
SAE No. 2 Friction Test Machine 3600 rpm Stepped Power TestJ2487_202511 (Current)11/21/2025
This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.The specific purpose of this document is to define a 3600 rpm Stepped Power Test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 3600 rpm and is intended as a standard procedure for common use by both suppliers and end users.The only variables selected by the supplier or user of the friction system are:a. Friction Materialb. Fluidc. Reaction PlatesThese three variables must be clearly identified when reporting the results of using this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document.This procedure is not intended to evaluate the initial coefficient or break-in characteristics. For this information, refer to SAE J2490.
Automatic Transmission and Transaxle Committee
ENGINE, BATTERY AND VEHICLE SIMULATION STRATEGIES FOR TRANSMISSION TESTING2024-01-311711/15/2024
WHY DO WE NEED SIMULATIONS? This paper is intended to provide a broad presentation of the simulation techniques focusing on transmission testing touching a bit on power train testing. Often, we do not have the engine or vehicle to run live proving ground tests on the transmission. By simulating the vehicle and engine, we reduce the overall development time of a new transmission design. For HEV transmissions, the battery may not be available. However, the customer may want to run durability tests on the HEV motor and/or the electronic control module for the HEV motor. What-if scenarios that were created using software simulators can be verified on the test stand using the real transmission. NVH applications may prefer to use an electric motor for engine simulation to reduce the engine noise level in the test cell so transmission noise is more easily discernable.
Johnson, Bryce
Powertrain Design Optimization for a Range-Extended Electric Pickup and Delivery Truck02-13-03-001410/2/2020
The ongoing electrification and data-intelligence trends in logistics industries enable efficient powertrain design and operation. In this work, the commercial package delivery vehicle powertrain design space is revisited with a specific combination of optimization and control techniques that promise accurate results with relatively fast computational time. The specific application that is explored here is a Class 6 pickup and delivery truck. A statistical learning approach is used to refine the search for the most optimal designs. Five hybrid powertrain architectures, namely, two-speed e-axle, three-speed and four-speed automatic transmission (AT) with electric motor (EM), direct-drive, and dual-motor options are explored, and a set of Pareto-optimal designs are found for a specific driving mission that represents the variations in a hypothetical operational scenario. The modeling and optimization processes are performed on the MATLAB™-Simulink platform. A cross-architecture performance and cost comparison is performed, which shows that two-speed e-axle is the optimal architecture for the selected application.
Anil, Vijay Sankar, Zhao, Tong, Zhao, Mingjie, Villani, Manfredi, Ahmed, Qadeer, Rizzoni, Giorgio
Parking Brake Control Identification - Vehicles with Hydraulic Brake Systems and Automatic TransmissionsJ2688_202007 (Current)7/13/2020
The scope and purpose of the SAE Recommended Practice is to provide standards for the control and indication of parking brakes in hydraulic braked vehicles over 4540 kg (10000 lb) GVWR. This recommended practice pertains to automatic transmission applications and supplements the SAE J915 recommended practice. This recommended practice does not address parking brake system performance. Parking brake system performance, both static and dynamic conditions, is the responsibility of the OEM vehicle manufacturer or manufacturers that modify the vehicle by adding special vocational required equipment (such as but not limited to outriggers, cranes, etc.).
Truck and Bus Hydraulic Brake Committee
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
Classification of Time Series Measurement Data for Shift Control of Automatic Transmission of Vehicles Using Machine Learning Techniques2020-01-02604/14/2020
An efficient approach to classify time series physical measurement data of shift control of automatic transmission for vehicles is presented. Comfortable acceleration is the essential factor of today’s vehicles. Shift control of automatic transmission of vehicles directly contributes to the comfortable acceleration. Since calibration of automatic transmission of vehicles is time consuming task for expert engineers, the development of autonomous calibration is desired to reduce product development period in today’s competitive automobile market. In the stage of product development, it is difficult to obtain a large amount of physical measurement data. Therefore, we need to develop machine learning method for limited amount of data. For this purpose, we develop the method to classify time series measurement data of shift control of automatic transmission of vehicles. We use support vector machine (SVM) as a machine learning technique. Features, used by SVM, of time series measurement data of shift control of automatic transmission of vehicles is selected by expert engineers. In addition, the computation is too heavy to explore the optimal value of the high dimensional parameter space for our classification problem with grid search. To remedy this problem, we employ Bayesian optimization. Bayesian optimization is known to be much more efficient than brute force grid search, because it is a sequential parameter search strategy for global optimization. Combining SVM and Bayesian optimization, we successfully built a high accuracy classification scheme. As the consequence, our proposed method enables highly efficient calibration of automatic transmission of vehicles in the stage of the product development. We demonstrate the performance of proposed method for classification problem of shift control of AISIN AW’s automatic transmission of vehicles. The results of our experimentation show the expected average accuracy of 0.940 for upshift and 0.939 for downshift, those are promising enough in an actual use.
Morikawa, Yusuke, Ishihara, Yasuhiro, Akita, Taku, Ide, Takanori, Miyake, Noriyuki, Moriyama, Eiji, Nakagawa, Hiroshi, Tabei, Yasuo, Utsuro, Takehito
Parameter Optimization of Two-Speed AMT Electric Vehicle Transmission System2020-01-04354/14/2020
At present, many electric vehicles are often equipped with only a single-stage final drive. Although the single-stage speed ratio can meet the general driving requirements of electric vehicles, if the requirements of the maximum speed and the requirements for starting acceleration or climbing are met at the same time, the power demand of the drive motor is relatively large, and the efficient area of the drive motor may be far away from the operating area corresponding to daily driving. If the two-speed automatic transmission is adopted, the vehicle can meet the requirements of maximum speed, starting acceleration and climbing at the same time, reduce the power demand of the driving motor, and improve the economy under certain power performance. This is especially important for medium and large vehicles. Therefore, this paper considers that the working torque and speed of the motor can be changed by optimizing the speed ratio of the transmission and changing the gear position so that the motor can work more in the high-efficiency zone. Taking an electric logistics vehicle with a drive motor & two-speed AMT power transmission system as the research object, this paper takes the vehicle’s power performance requirements and AMT design requirements as constraints, and the vehicle energy consumption and driving range as the optimization objective, and adopts generic algorithm to optimize the parameters of the transmission system. Then, a complete vehicle model was built with software to verify the energy consumption of the vehicle, so as to verify the advantages of the two-gear transmission scheme. The results show that compared with the single-gear transmission scheme, the optimized two-gear transmission scheme improves the vehicle’s power performance and economy, and reduces the demand for motor power and torque.
Cui, Jian, Tan, Gangfeng, Feng, Jia'ao, Tian, Zhongpeng, Agyeman, Philip
Main Features of Forming the Transmission of an Active Multi-Link Road Train2020-01-04274/14/2020
The development of the economy and the associated growth in trade both within the country and international transport, the associated construction and development of transport routes using elements of intelligent transport systems constantly require increasing the efficiency of trunk transportation. In addition, the development of new economic regions with an undeveloped road network is impossible without high-capacity motor vehicles and cross-country ability. To achieve these goals, the creation of active road trains, including multi-link ones, based on non-traditional technical solutions, is required. The idea of using multi-link trains in the system of intercity and international transportation is not new. However, at the present stage of development of automotive technology requires rethinking and use of new achievements of science and technology. At present, the process of changing the design of land vehicles, qualitatively changing their structure and composition of the main power devices based on the integration of electronic, electrical, hydraulic, pneumatic and mechanical elements and significantly increasing the role of electronics and control systems, i.e. widespread introduction of mechatronic systems and modules in the design of a road train. The article describes some aspects of constructing the transmission of active road trains based on the mechatronic modular principle. Materials of the article are based on the results of theoretical and experimental studies conducted by the authors and with their participation. In this article, the term “mechatronics” is understood as a synthesis of electromechanics and microelectronics, combined by a common control and optimized according to system-wide criteria.
Belousov, Boris, Haritonchik, Sergey, Keller, Andrei, Bakhmutov, Sergey, Berdnikov, Alexey, Alyukov, Sergei, Alyukov, Alexander
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
Nissan's 2020 Frontier gets new V6, 9-speed20AUTP03_153/1/2020
More transmission gears and greater engine horsepower should enliven the 2020 Nissan Frontier midsize pickup truck. “We're launching a new transmission and new engine in the current Frontier, and this powertrain will be the heart of the next-generation Frontier coming in 2021,” said Tiago Castro, Nissan North America's director of commercial business unit for pickup trucks, SUVs and vans. Castro spoke with Automotive Engineering during the 2020 Chicago Auto Show. Replacing the current standard 152-hp 2.5-L 4-cylinder and an optional 261-hp 4.0-L V6, the 3.8-L V6's first application is the 2020 Frontier. “We're getting 49 more horsepower with the new V6, which is best-in-class standard horsepower,” Castro said. The new 3.8-L engine's torque, rated at 281 lb-ft (381 Nm), matches the outgoing 4.0-L V.6.
Buchholz, Kami
Two-Speed Transmission Gear Shift Process Analysis and Optimization Using Genetic Algorithm08-09-01-00011/16/2020
Electric Vehicle (EV) equipped with two-speed transmission has benefit in improving dynamic performance and saving battery consumption. However, during gear shift process, torque interruption and shift impact may lead to a bad shift quality. This work investigates gear shift process in an Automated Manual Transmission (AMT) configuration-based two-speed transmission. First of all, a typical gear shift process is analyzed. Parameters like motor speed, shift force, motor torque change rate, and speed difference between synchronizer and target engage gear are all included to find the relationships with shift duration. Then vehicle jerk is introduced as a criterion to evaluate shift impact. Besides, a comprehensive shift control strategy is developed. While keeping the output torque at wheels unchanged, the shift strategy also improved motor working efficiency after gear shift. Therefore, to determine an optimum shift strategy and achieve a balance among different parameters, Genetic Algorithm (GA) multi-objective optimization method is implemented. Through GA optimization, several solutions are presented and discussed. The final results can well satisfy the requirements of different objectives. This work provides a novel and efficient method for shift strategy development.
Cao, Zhan, Yang, Jiansen, Wang, Xinyu
Dynamic modeling and simulation of a powertrain system with a six-speed automatic transmission2019-36-01001/13/2020
The constant growth of the automotive market demands for comfort to the user and energy efficiency have caused the intensification of the industry researches and development of the automatic transmissions (AT). However, vehicles equipped with these gearboxes entails in higher fuel consumption levels than the one required by vehicles equipped with manual transmission. In the automotive industry due to the advantages offered using computer simulations, such as fast evaluation an optimization, many researchers are using virtual models for optimization of dynamic behavior of systems and fuel consumption. Aiming to study the dynamic behavior of an AT and the influence of its components on that behavior, this paper presents an AT dynamic model developed in MATLAB® / Simulink®. The AT model has three main subsystems: a torque converter model, which includes the dynamic of both the forward flow mode and the reverse flow mode; a Lepelletier gearbox model, composed by a set of three planetary gearsets in parallel, resulting in a six forward speeds gearbox; and a gear-shift schedule, which has the vehicle speed and accelerator pedal position as inputs of the model and the gear that should be selected in that condition as output of the model. The torque converter subsystem considers the transient and steady-state dynamic and their mainly operation dynamic characteristic: the conversion range, in which occurs a torque amplification and the stator is held; the coupling range, in which the stator freely rotates; and the transition periods from the forward to the reverse flow mode and vice-versa. The axial volume flow of the fluid, the speed and the torque of the three wheels (impeller, stator and turbine) were verified for the dynamic analysis of the system. In addition, the AT model was integrated into a MATLAB® / Simulink® vehicular dynamics and fuel consumption model in order to be analyzed under the ABNT 7024 standard speed profile.
de Araujo, Marcel T. da S., Falleiros, Murilo F., Gioria, Gustavo dos S.
Inside Tremec's SUPERCAR DCT20AUTP02_041/1/2020
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 box, the automated half of the equation - mechatronic actuators to engage the clutches and shift the gears - was beyond their ken. Tremec filled that need in 2012 by purchasing Hoerbiger Drivetrain Mechatronics, a Belgium-based supplier of electronic dual-clutch actuators with a customer list including AMG-Mercedes, Ferrari and McLaren.
Sherman, Don
Advanced Bench Test Methodology for Generating Wet Clutch Torque Transfer Functions for Enhanced Drivability Simulations2019-01-234012/19/2019
A wet clutch continues to play a critical role for step-ratio automatic transmissions and finds new utilities in hybrid and electrified propulsion systems. A torque transfer function is often employed in practice for sophisticated clutch slip controls. It provides a simple, yet practical framework to represent clutch torque as a function of actuator force. An accurate transfer function is also increasingly desired in today's vehicle design process to enable upfront assessment of clutch controls through simulations. The most common approach is based on Coulomb's linear friction model, where the coefficients are adaptively identified based on vehicle data. However, it is generally difficult to tune Coulomb's model for hydrodynamic behaviors even if the reference vehicle data are available. It also remains a challenge to produce in-vehicle clutch behaviors on a component test bench to determine realistic transfer function before prototype vehicles are built. SAE#2 test procedure is the industry standard for evaluating clutch frictional behaviors. It is a viable tool for durability assessment, but not designed to characterize hydrodynamic behaviors for clutch controls. This research focuses on the development of a methodology to generate realistic clutch transfer functions using an advanced engagement bench tester. The test stand is equipped with programmable slip and force controllers to replicate both torque phase and inertia phase of gear shifting. It accommodates a clutch module, not only the clutch pack, to reproduce actual in-vehicle lubrication conditions. The clutch behaviors are characterized for various combinations of operating conditions. The bench test data are compared with SAE#2 data to highlight the sensitivity of hydrodynamic behaviors to force and slip profiles. A regression technique is utilized to represent clutch behaviors as a transfer function in non-linear forms using data from the advanced tester. Shift simulations are conducted to demonstrate the value of realistic transfer functions to enable upfront drivability assessment for control development.
Haria, Hiral, Fujii, Yuji, Pietron, Gregory M., Sun, Anna, Tsuchiya, Takahiro, Miyagawa, Masatoshi, Nakamura, Shinji, Wendel, Matthew, Miyoshi, Hiroya, Wang, Pengchuan, Katopodes, Nikolaos
Understanding Base Oils and Lubricants for Electric Drivetrain Applications2019-01-233712/19/2019
ABSTRACT The penetration of hybridization and electrification (HEV and EV) technology into automotive powertrain designs is an evolving trend resulting from global regulations intended to reduce transportation-related emissions of greenhouse gases and other pollutants and to improve vehicle fuel efficiency. In many HEV and EV hardware designs, drivetrain fluids have contact with the integrated electric motor (e-motor), which requires electrical and thermal properties to be considered in addition to traditional fluid properties. This paper discusses new insights gained around electrical and thermal properties of drivetrain fluids, with a specific emphasis on understanding the critical impacts of base oils (BOs). Electrical and thermal properties data as a function of temperature for a range of BOs as well as automatic transmission fluids are shared. We found that BOs and their viscosities play a critical role in cooling performance, while additives play a critical role in electrical conductivity (EC). That being said, we also have observed that additives in BOs can modify cooling performance. We will demonstrate how each component in the additive package affects EC and in some cases cooling performance. The successful utilization of this knowledge is demonstrated on a proof-of-principle basis to show that fluids with appropriate electrical and thermal properties can be designed to meet critical factors for electrification such as cooling capacity and EC, while still maintaining essential performance features for conventional driveline fluids.
Kwak, Yungwan, Cleveland, Christopher, Adhvaryu, Atanu, Fang, Xinggao, Hurley, Susie, Adachi, Tsuneo
Hydrodynamic Drives TerminologyJ641_201912 (Current)12/2/2019
Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. EXAMPLE: Two systems of blade angle designations are described. Consequently, when a blade angle is specified, the system should be designated. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.
Automatic Transmission and Transaxle Committee
Automatic Transmissions - Schematic DiagramsJ647_201911 (Current)11/19/2019
The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.
Automatic Transmission and Transaxle Committee
Study on Engine Start Vibration Index in a Hybrid Powertrain Using Torque Sensor and Cylinder Pressure Sensor2019-01-503411/4/2019
This paper presents an investigation of drivability issue of engine start-stop. Hybrid vehicles provide excellent benefits regarding fuel efficiency and emission. However, vibration results from constant engine start and stop events generate drivability issues, thus compromising driving comfort. This paper has designed a high speed torque sensor to capture instantaneous torque at the engine shaft. Its consequences help to find out the most suitable index of vibration severity. This paper is organized in four sections. The first section introduces the powertrain to be studied. The second section introduces development of a specially designed torque sensor. The torque sensor is installed between the engine and ISG (Integrated Starter Generator), alongside with an encoder. The torque sensor is utilized to collect the instantaneous shaft torque on occasion of engine start. In the third section, this paper has performed two experiments. Firstly, a typical engine start process (from 0 to 650 rpm) is studied. Instantaneous shaft torque, encoder signal and cylinder pressure signals are gathered and synchronized. Cranking phase and initial combustion phase is observed. It is concluded that torque generated from cylinder pumping air is the main contributor to the engine torque ripple, which is the main cause of vibration. Use that, three vibration index candidates are bought out, and square of angular acceleration is chosen. Then, this paper performed another experiment with an engine working at 1000 rpm and 100 Nm to examine the performance of vibration index. The results show the effectiveness of vibration index.
Yang, Fuyuan, Du, Lei, Hu, Yaodong
WHAT WE'RE DRIVING19AUTP11_0811/1/2019
While I'm among the first media to have driven the mid-engine 2020 Stingray, my time in the car (during the North American Car, Truck and Utility of the Year judging) was but 45 minutes. A very invigorating 45 minutes. My Torch Red coupe came with a special feature: Corvette ride-and-handling engineer Mike Hurley, who rode shotgun with me through the Michigan countryside. As we discussed C8 development, Mike schooled me on the magneto-rheological (MR) dampers that underpin the desirable $5,000 Z51 performance package. With three driver-selectable suspension modes - Tour, Sport, Track - the MR dampers deliver a compliant ride in town and plushness on the open road, while transforming the car into a sharp track-day tool. Crossing railroad tracks is no longer torture in a Corvette.
Performance Analysis of an Automated Manual Transmission Controller for Two-Wheeler2019-28-012510/11/2019
This research paper presents controller development and its performance analysis for two wheeler. The comparison for different performance parameters is carried out with and without automated manual transmission (AMT) controller. The AMT considered in this case, includes a conventional manual transmission gear-box with conventional clutch pedal. It is equipped with clutch actuation with the help of linear actuator and the gear shifting using servo motor. The upshift and downshifting of the gears and the clutch actuation is done through the decisions of controller. The results generated during the engine dynamometer test are used as input creating two wheeler vehicle model using AVL cruise software. This vehicle model is used to predict vehicle performance. The vehicle performance results are validated with chassis dynamometer test data. The vehicle model is modified for generation of gear shifting plot. Also Gear shift program (GSP) is generated using the GSP generation module of AVL cruise software. The two criteria used for GSP generation are fuel economy and vehicle acceleration performance. The simulation results include generation of gear shifting graph which covers range from 0-120 kmph. The hysteresis zones are established during up shift and downshift, based on actuator and sensor limitations. The automated manual transmission controller algorithm has used the input of two parameters which are vehicle speed and throttle position. The simulation shows 4% reduction with generated gear shift plot.
Patil, Saurabh Sunil, Wani, Kiran Pralhad
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% improvement in fuel economy over the previous one.
Sukumar, Arun
Domestic Performance Torque Converter ManufacturingJ2440_201910 (Current)10/9/2019
The scope of this SAE Draft Technical Report is to establish dimensional standards for high-performance domestic torque converter manufacturers. Many torque converter manufacturers build converters to their own standards. Some of these standards may be outside of the specifications that define a quality performance torque converter.
Motor Vehicle Council
Rectangular Cross Section Polymeric Sealing RingsJ2310_201910 (Historical)10/9/2019
The purpose of this SAE Recommended Practice is to establish guidelines for the automatic transmission and hydraulic systems engineer to design rectangular cross section seals for rotating and static grooved shaft applications. Also included are property comparisons of polymeric materials suitable for these applications. Historically, material covered in this document is not intended to include aluminum contact applications.
Automatic Transmission and Transaxle Committee
Engineering the 2020 CHEVROLET CORVETTE19AUTP09_019/1/2019
The eighth-gen (C8) Corvette is a creative mix of novel and traditional technical solutions unleashed at a shockingly low base price. Two days before the 50th anniversary of astronaut Neil Armstrong's leap for mankind and 10 years after General Motors emerged from bankruptcy, the camouflage was finally ripped from the eighth-generation (C8) 2020 Chevrolet Corvette. As widely anticipated, C8 now flaunts a mid-engine layout that ostensibly puts it on equal terms with the world's most venerated supercars. After six decades of experimentation and concept-car teasing, GM acknowledged that the new Stingray will enter production before year's end. The truly shocking announcement is a base price of $59,995 including destination, only $3,000 more than today's front-engine C7. Along with moving the cockpit forward 16.5 inches (419 mm) to facilitate shifting the engine rearward, the new Corvette is an innovative mix of novel and traditional engineering solutions.
Sherman, Don
One-Way Clutches - Nomenclature and TerminologyJ1087_201907 (Current)7/24/2019
The definitions and illustrations in this SAE Recommended Practice are intended to establish common nomenclature and terminology for automotive transmission one-way clutches.
Automatic Transmission and Transaxle Committee
Testing Methods and Signal Processing Strategies for Automatic Transmission Transient Multiplexed Pressure Data2019-01-15006/5/2019
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
Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs2019-01-14556/5/2019
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, accurate system-level integrated models are becoming a requirement to solve modern NVH problems. Combining the optimal balance between simulation and experimental data, this article describes a joint effort between Ford and Gamma Technologies to develop a general methodology to perform full-vehicle low frequency NVH analysis. Using GT-SUITE software, a non-linear multi-physics simulation model of a rear wheel drive HEV was created. The model was exercised to accurately evaluate the effects of powertrain control strategy and component selection on low-frequency NVH performance during a tip-in regeneration, downshifting and in-gear acceleration maneuvers while minimizing the computational cost.
Gomez, Llorenc Foraste, Zeman, Jonathan, Liu, Jack
Long time coming19AUTP06_066/1/2019
After six decades of teasing enthusiasts with intriguing concepts, Chevrolet is launching an all-new Corvette with its engine located where Zora intended-behind the driver. In the Spring of 1957, while pondering the demise of Chevrolet's Corvette Super Sports racer at Sebring's 12-hour endurance race, legendary Corvette godfather Zora Arkus-Duntov concluded, “Heat source must be behind driver.” The official explanation offered for dropping out after 29 laps was a failed rear-suspension bushing-but the actual show-stopper was that driver John Fitch's feet were being cooked by the exhaust-header pipes snaking around the SS's sheet magnesium ‘firewall.’ Sixty-two years later, the Corvette development trek initiated by Arkus-Duntov's brainstorm reached New York's Times Square, when a camouflaged prototype (see cover image) driven by chief engineer Tadge Juechter and with GM CEO Mary Barra as passenger, finally confirmed that the 2020 Corvette will have its engine located behind the driver.
Sherman, Don
Ford demos latest digital tools at flagship transmission plant19AUTP05_135/1/2019
Ford recently provided media with a look at some of its latest digital manufacturing tools, opening up the floor at one of the world's largest transmission plants to showcase the quality- and productivity-driven initiative. The tour of Ford's Livonia Transmission Plant (LTP) was part of a Detroit-area Manufacturing in America conference hosted by Siemens. Though showcasing the latest tools in use today, Ford stressed that this was a journey that began in earnest over a decade ago-and is only just beginning to be leveraged. The digital systems Ford is employing permit a more efficient path between its computer-aided engineering (CAE), the creation of production/supply systems and the assembly process itself, improving quality by validating metrics in real time and gathering a swarm of data for analysis. Exceptional granularity in its component traceability provides a wealth of on-site data to improve quality, but leveraging such data in the cloud also can improve vehicle-specific characteristics at distant, final-assembly locations.
Seredynski, Paul
Acceleration Testing of 2000 Van Hool 45 Foot Motor Coach2019-01-04314/2/2019
The time/distance relationship for a motor coach accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 45 foot long 2000 Van Hool motor coach equipped with a Cummins ISM engine and an Allison B500 6-speed automatic transmission. These tests included three load configurations and two different acceleration rates, normal and rapid. Data were gathered with a Racelogic VBOX IIIi.
Grimes, Wesley, Balasa, Jonathan, Wilcoxson, Greg
Multi-Objective Design Exploration of Automatic Transmission Casing Using Genetic Algorithm and Data Mining Techniques2019-01-08214/2/2019
This study implemented multi-objective design exploration for an automatic transmission casing using genetic algorithm (GA) and data mining techniques. In general, real-world design problems are requested to be solved by considering all relevant disciplines simultaneously, which is called multidisciplinary design optimization (MDO). We often face the difficulty in balancing these different disciplines to satisfy required performance, such as durability, stiffness, noise, vibration, harshness, mountability, weight, and manufacturability considered in this study. In addition, we often have to improve development efficiency for shortening of the development period. Therefore, MDO has been widely implemented for taking improved design candidates according to required specifications and making a decision to fix conceptual design in an early stage. MDO is usually considered as the multi-objective optimization which aims to obtain the set of Pareto-optimal solutions. These solutions happen due to the trade-off relationships between competing objectives, and are useful to characterize the potential of a design product to be optimized. From the aforementioned points of view on MDO, this study applied GA for the MDO of the automatic transmission casing because of the superior solution searching capability in multi-objective optimization. Our design objectives were to minimize the casing weight and noise by changing the wall thickness. We divided the whole casing surface into 669 regions, and define the thickness in each region individually as the design variable in the present MDO. Since GA is computationally expensive due to the population-based search, this study combined GA with Kriging surrogate models to reduce time required for evaluating the searched solutions. Furthermore, during the optimization process, we analyzed the obtained solutions to see the trade-off relationships using data mining techniques. Finally, we obtained the shape of automatic transmission casing that was lighter than initial shape and satisfied required performance.
Toda, Kentaro, Yoshikawa, Hiroki, Shimoyama, Koji
Recognizing Similarities in Automatic Transmissions of Vehicles by Using Time Series Data and Autoencorders2019-01-03434/2/2019
In recent years, the development time of vehicles has further accelerated, and automation of the development is an urgent task. One example of time wasting tasks is gear-shift calibration. For this purpose, Kawakami et al. have studied OK/NG classification of shift quality by using neural networks. However, their classifiers have a problem in versatility over different AT hardwares. In this paper, we develop autoencoders to realize similar/not-similar classification on three AT hardwares of vehicles. These hardwares have different lock-up multi/single-plate clutch structures. Experimental results show that the performance of similar/not-similar classification is high in terms of AUC.
Kawakami, Takefumi, Ide, Takanori, Tomita, Kiyohisa, Moriyama, Eiji, Hoki, Kunihito, Muramatsu, Masakazu
Acceleration Testing of 2011 MCI J4500 45 foot Motor Coach2019-01-04094/2/2019
The time/distance relationship for a motor coach accelerating from a stop is often needed to accurately assess the events leading up to a collision. Several series of tests were conducted to document the low speed acceleration performance of a 45-foot long 2011 MCI J4500 motor coach equipped with a Detroit Diesel Series 60 engine and a ZF AS Tronic 12-speed automatic transmission. These tests included three load configurations and two different acceleration rates, normal and rapid. Data were gathered with a Racelogic VBOX IIIi.
Grimes, Wesley, Wilcoxson, Greg, Balasa, Jonathan
CVT, Promising Solutions for Electrification2019-01-03594/2/2019
A single speed transmission for electric vehicles (EV) puts specific requirements on the electric motor and battery to enable the full characteristics as offered by the internal combustion engine such as driving large distances at higher speed or towing a trailer. EV developers are facing several challenges in extending driving range, reducing recharge times and finding a performance and efficiency compromise between low and high-speed conditions. This study proposes a combination of a dedicated electric machine and a Continuously Variable Transmission (CVT) that offers a chance to overcome these challenges. The result is an efficient and cost effective solution where the surplus cost of the CVT is recovered within the powertrain by lowering cost of the electric components, cooling system and battery. A CVT reduces the maximum torque and speed requirement of the electric machine which enables a reduced size and cost of the active parts. The combination of a downsized electric machine and a pushbelt CVT can deliver the good performance that consumers expect from their EV. This paper combines the results of research into various topics to support these statements. A simulation based comparative study of various EV powertrain configurations shows that with respect to the single speed EV, efficiency benefits around 13% on WLTC are possible. A cost study based on the bill of materials furthermore concludes that a 6% cost benefit is achievable.
Van der Sluis, Francis, Romers, Luc, Van Spijk, Gert-Jan, Hupkes, Ingmar
Development of a Low Loss Clutch for CVT Reverse Function2019-01-07744/2/2019
Continuously variable transmissions (CVT) provide superior fuel economy by enabling internal combustion engines to operate at their “sweet spots”. However, there is still potential to improve CVT system’s mechanical efficiency, and further enhance vehicle-level fuel economy. In the past, extensive research work has focused on the core continuously variator unit (CVU) that includes pulleys and a belt or chain. Another thread of research has centered on optimization of CVT clamping force control to reduce hydraulic system loss. Nonetheless, to the best of our knowledge, very little research has looked into the planetary gear sets and clutches that enable the CVT system to switch between forward, neutral and reverse gears. The state-of-the-art reverse clutch usually consists of multiple friction and steel plates, and is normally open during all forward driving maneuvers. The relative speed between friction and steel plates is identical to turbine speed, which generate spin loss. We believe there is an opportunity to improve the CVT system mechanical efficiency by replacing the reverse plate clutch with a low loss clutch, for example a binary clutch. At first, we studied the theoretical spin loss associated with plate clutches. Secondly, we identified the most challenging shifting maneuver using the lever diagram analogy. Thirdly, we proposed a control strategy to address the most critical rolling garage drive-to-reverse shift, and conducted one-dimensional simulation using an AMESim model to validate our strategy by comparing our simulation result with available vehicle data. At last, we obtained spin loss data from dynamometer testing to evaluate the potential fuel economy benefit.
Duan, Chengwu, Lee, Chunhao, Yao, Jian, Samie, Farzad, Huang, Ying
Vibration Energy Harvesting Damper in Vehicle Driveline2019-01-07824/2/2019
The vibration mitigation could provide mutually interconnected results: reduction of undesired vibration levels and generating of additional electrical power. New Vibration Energy Harvesting Damper (VEHD) schematically based on author’s US Patent 7,464,800 and consists of two main components: Tuned Mass Damper and Generator of Electricity. The analysis of dynamical performance and effectiveness of developed VEHD applicable for all types of Automotives is presented. The invented VEHD could be fabricated in two main versions: for rectilinear vibration applications and for angular rotational applications, and should be integrated in driveline. Mathematical model of dynamical behaviour is developed. An example of automatic transmission 545 RFE is considered for simulation analysis. The structural study of invented schemes shows some perspective features and directions for design. Specific particularities and control properties are provided for explanation of effectiveness of VEHD operation. Test results illustrate the compliance with theoretical predictions, efficiency of proposed VEHD and some new opportunities for their applications.
Nerubenko, George
Optimization of the Process of Acceleration of a Vehicle Taking into Account the Regimes of Operation of Its Engine2019-01-07764/2/2019
Currently, in order to effectively use the engine's energy resources and implement the required indicators of the traction, speed and fuel-economic properties of a vehicle, designers and manufacturers are trying to realize some certain properties to the transmission design that will ensure the most complete coordination of their joint work. However, even the optimal constructive solution cannot be universal, i.e. what is good for some operating conditions is not effective for other conditions. Therefore, today it is economically expedient to create vehicles intended for a certain, relatively narrow range of operating conditions. A wide range of modern continuously variable transmissions (CVT), as well as automatic control systems make it possible to radically change the approach to the design of vehicle transmissions. It remains only to determine the algorithms for changing the gear ratio of the CVT. The technique of a choice of optimum transfer numbers of CVT of a car in view of modes of movement and work of its engine is offered. The results of calculation of the traction-dynamic and fuel-economic parameters of a car with CVT, the gear ratios of which change during the movement in accordance with the proposed procedure, in comparison with the actual prototype, confirmed the accepted optimization hypothesis and gave all grounds for recommending the application of this technique to practice when choosing the gear ratios of continuously variable transmission, depending on the mode of movement of vehicle and regimes of operation of its engine.
Ulanov, Alexander, Aliukov, Sergei
Control Strategy and Energy Recovery Potential for P2 Parallel Hybrid Step Gear Automatic Transmissions2019-01-13024/2/2019
The purpose of this investigation is to present a control strategy and energy recovery potential for P2 parallel hybrid step gear automatic transmissions. The automatic transmission types considered for the investigation are rear wheel drive 8 speed dual clutch transmission and 8 speed planetary automatic equipped each equipped with an electric motor between the engine and transmission. The governing equations of clutch-to-clutch upshift controls are presented and are identical for each transmission type. Various strategies are explored for executing the upshift under a range of input torques, shift times and engine torque management approaches. The differences in energy recovery potential based upon control strategy is explored piecewise as well as through a DFSS study. On a comprehensive drive cycle consisting of FTP 75, US06 and HWFET test cycles, it is shown that upshift regen torque management can be equivalent to approximately 0.8% of the total fuel energy used. Additionally, it is shown that the utilization of the P2 electric motor is a further enabler to reduced shift times and improved shift quality at part throttle without compromise to net battery energy or fuel consumption.
Robinette, Darrell, Orlando, Joshua
A Generalized Component Efficiency and Input-Data Generation Model for Creating Fleet-Representative Vehicle Simulation Cases in VECTO2019-01-12804/2/2019
The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. Any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require generic inputs or reconstructing realistic component input data. The current study attempts to address this issue by developing a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10. Subsequently, evaluating the accuracy of the process, the simulation results were compared with reference VECTO results supplied by various vehicle manufacturers. The results showed that the difference between simulated and reference CO2 emissions was on average -0.6% in the Long Haul cycle and 1% in the Regional Delivery. Such a process could be a powerful tool for calculating HDV CO2 emissions for development and analysis purposes, e.g. for new vehicle prototypes or multistage vehicles, and for creating VECTO equivalent models that can be used to assess alternative operating conditions and mission profiles of existing vehicle models. The methodology was applied for creating input of various components in the US tool for HDV certification, GEM, for generic sample-vehicle models available.
Zacharof, Nikiforos, Tansini, Alessandro, Prado Rujas, Iker, Grigoratos, Theodoros, Fontaras, Georgios
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
Application of Empirical Asperity Contact Model to High Fidelity Wet Clutch System Simulations2019-01-13014/2/2019
Wet clutches are complex hydrodynamic devices used in both conventional and electrified drivetrain systems. They couple or de-couple powertrain components for applications such as automatic shifting, engine disconnect and torque vectoring. Clutch engagement behaviors vary greatly, depending on design parameters and operating conditions. Because of their direct impact on vehicle drivability and fuel economy, a predictive CAE model is desired for enabling analytical design verification processes. During engagement, a wet clutch transmits torque through viscous shear and asperity contact. A conventional Coulomb’s model, which is routinely utilized in shift simulations, is inadequate to capture non-linear hydrodynamic effects for higher fidelity analysis. Extensive research has been conducted over the years to derive hydrodynamic torque transfer models based on 1D squeeze film or 3D CFD. They are typically coupled with an elastic asperity contact model for mechanical torque transfer. However, the recent advancement reveals no significant asperity deformation at the frictional surface during engagement and establishes a new empirical asperity contact model. This paper describes the integration of the empirical asperity contact model with CFD for developing a high-fidelity wet clutch engagement model. The asperity models are examined in detail for four friction materials to highlight distinct contact behaviors. They are coupled with 3D CFD model in OpenFOAM for engagement simulations, demonstrating the importance of selecting the right asperity model for predictive clutch analysis. A breakdown of hydrodynamic and mechanical torques is provided, enabling numerical examination of clutch engagement processes. Simulation results are compared with clutch module test data that is specifically designed to replicate actual shifting conditions. It is found that accurate simulation of a complete clutch system requires not only engagement physics, but also in-depth understanding of actuator characteristics such as seal drag.
Haria, Hiral, Fujii, Yuji, Pietron, Gregory M., Wang, Pengchuan, Katopodes, Nikolaos, Miyagawa, Masatoshi, Tsuchiya, Takahiro, Nakamura, Shinji, Wendel, Matthew, Miyoshi, Hiroya
Efficiency Evaluation of Lower Viscosity ATF in a Planetary Automatic Transmission for Improved Fuel Economy2019-01-12964/2/2019
With continued industry focus on reducing parasitic transmission and driveline losses, detailed studies are required to quantify potential enablers to improve vehicle fuel economy. Investigations were undertaken to understand the influence of lower viscosity Automatic Transmission Fluids (ATF) on transmission efficiency as compared with conventional fluids. The objectives of this study were to quantify the losses of lower viscosity ATF as compared with conventional ATF, and to understand the influence of ATF properties including viscosities, base oil types, and additive packages on fuel efficiency. The transmission efficiency investigations were conducted on a test bench following a vehicle-based break-in of the transmission using a prescribed drive cycle on a chassis dynamometer. At low temperature, the lower viscosity ATF showed a clear advantage over the conventional ATF in both spin loss and loaded efficiency evaluations. At high temperature, mixed results were obtained; it appeared the chemistry of ATF influenced the results. Overall, using the low viscosity fluid tends to improve loss behavior, but the benefits can be offset if the transmission hardware employed is not specifically designed for low viscosity fluids. Potential noise factors of the test method were discussed along with the strategies to reduce them which included oil flushing method, break-in method, and selection of test transmission design. This project was undertaken and financially supported by the Transmission Working Group (TWG) of the United States Council of Automotive Research (USCAR).
Tang, Haiying, Zreik, Khaled, Ohtani, Hiroko, D'Anna, Thomas, Murtagh, Jason E., Wellmann, Thomas
WHAT WE'RE DRIVING19AUTP04_094/1/2019
Toyota pickups fitted with gonzo oversize tires, long-travel suspensions and M1 Abrams-quality skid plates have been part of the U.S. off-roading scene since before “Ironman Ivan” Stewart won the Baja 1000 in 1993. His victory ride was developed by TRD, the automaker's U.S. race-engineering group, whose work is manifest in 2019 TRD versions of Tundra, Tacoma and 4Runner production models. As with the off-road-oriented pickups from other OEMs, the Tundra TRD Pro delivers big fun on the rocks. But it demands some compromise as a daily driver, particularly in ride quality, unless your commute is in Colorado's San Juan mountains.
The Development of Gear Tooth Micro Geometry Analysis Method for the Transmission Gear Noise Robustness2019-01-14143/25/2019
Transmission error has been well known as the main source of excitation about transmission gear whine noise. To minimize transmission error in the gear system, various analysis methods have been studied and applied for long time. Many researchers were focused on gear micro geometry to achieve the low level of transmission error. But, if the gear is misaligned by several factors such as clearance and manufacturing tolerance error, then the gear noise can rapidly and unexpectedly be increased. To overcome this problem, this new analysis method has been developed and introduced. A transmission system simulation model was constructed, which considers various factors of transmission components such as clearance, stiffness and so on. The deformation and vibration characteristics of finite element models were validated by making comparison with frequency response function experiment. Through the Placket-Burman screening method, the lead slope was found out one of the most sensitive factor for the transmission error. Full factorial combination analysis for the lead slope was performed under the various driving conditions. As a result, the transmission error distribution map according to the gear tooth modifications and various torque conditions was introduced. The transmission error map proposed by this analysis could make it easy to find the correction of gear micro geometry which is robust to noise. After all, vibration distribution of new planetary gear could result in 5dB reduction compared to former transmission. Hyundai-Motors 8 speed automatic transmission was developed successfully by using this new analysis method.
Choi, Jae Hyuk, Lee, Hyun Ku, Suh, Hyun Seung, Lee, Soo Hong
FCA debuts new Ram Heavy Duty pickups19AUTP03_163/1/2019
FCA's Ram truck division unveiled its new 2019 Heavy Duty (HD) pickup truck lineup at the 2019 North American International Auto Show (NAIAS). The new HD pickups feature the slick interiors and tech from Ram's new 1500 line, significant powertrain and chassis upgrades and all-new front and rear sheetmetal. The Ram HD lineup will face off against Chevy's new HD pickup offerings and Ford's established F-Series and includes 2500/3500 capacities in regular, crew and mega-cab configurations. Since it's a heavy-duty truck launch, Ram is of course touting new capability figures for its HD lineup, which retains its basic cab architecture, but sees nearly every other part of its chassis upgraded. A new 6.7-liter turbo-diesel producing 1,000 lb·ft of torque-the first HD pickup to break the fourfigure torque-output barrier-combines with a redone frame that's now 98.5% high-strength steel to provide what Ram claims are class-leading figures of 35,100-lb (15,921-kg) towing and 7,680-lb (3,565-kg) of payload.
Seredynski, Paul
2020 Ford Super Duty debuts all-new OHV V819AUTP03_173/1/2019
The 2020 Ford F-Series Super Duty will arrive with the heavy-duty pickup truck's best-ever conventional, gooseneck, and fifth-wheel trailer towing and payload ratings. “What makes these highest-ever ratings possible is our strongest-yet Super Duty powertrain offerings,” said Dave Filipe, Ford VP of global powertrain during the 2020 F-Series Super Duty's January 30 debut in Detroit. Automotive Engineering spoke with Ford powertrain engineers about the all-new pushrod V8, the third-generation 6.7-L Power Stroke diesel V8, and the all-new 10-speed TorqShift automatic transmission offered on the 2020 F-250, F-350, and F-450 trucks, which are expected to begin shipping to dealers in the fall of 2019.
Buchholz, Kami
2019 Chevrolet Blazer just right for the voracious SUV market19AUTP03_183/1/2019
Leaving its dirt roots in the past, the all-new 2019 Chevrolet Blazer is a stylish, on-road-focused 2-row SUV that slots between Chevy's Equinox and Traverse, deftly closing a gap in its SUV lineup. Based on the GM global-C1 architecture underpinning the Cadillac XT5, the new Chevy Blazer is quite conventional but contains a host of keen features including a versatile AWD setup. The all-new 5-door, 5-passenger FWD/AWD Blazer will compete with other 2-row SUVs-including the Ford Edge and Nissan Murano-in a segment which relies heavily on styling for purchase consideration. “The first time we saw the concept sketches we were excited about it,” said Jeff Boike, the Chevrolet Blazer program engineering manager. “I think the big challenge for engineering is to deliver. A lot of times you'll see a theme, and by the time you incorporate all the engineering criteria, you kind of lose the very thing you were after.”
Seredynski, Paul
New V8, big towing, trick features and tech for 2020 Chevy Silverado HD19AUTP03_153/1/2019
With pickup trucks seemingly taking over the personal-vehicle market, it's no surprise the Detroit Three automakers are devoting more attention than ever to the pickups-for-real-work side of the equation, too. In launching the 2020 Chevrolet Silverado HD line at a high-profile event at the trucks' newly-expanded assembly plant in Flint, Michigan, General Motors president Mark Reuss said, “At GM, we've been preparing for this changing market for years.” So have Ford and FiatChrysler, too, though, and with all three powering into 2019 with all-new (FCA's 2019 Ram HD) or significantly updated (Ford 2020 Super Duty) 2500/3500 heavy-duty pickups, expect competitive fireworks.
Visnic, Bill
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