Browse Topic: Transmission gears

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Minimum Weight Design of an Electronic Continuously Variable Transmission for Rotorcraft ApplicationsF-0081-2025-02905/20/2025
This paper, explores the design and sizing of a planetary gear-based electronic continuously variable transmission (ECVT) for implementation of a parallel gas-electric hybrid helicopter propulsion system. The ECVT consists of a differential planetary gear transmission (PGT) and an electric motor/generator (MG) unit. The ECVT enables power-flow between engine, motor and helicopter main rotor. The parallel arrangement enables the main rotor speed to varied continuously based on the MG speed while the engine speed can remain constant. The performance benefits enabled by the main rotor speed variation capability are offset by the added weight penalties introduced by the ECVT system. By considering factors such a as gear tooth bending and contact stress, bearing loads, required motor torque, planetary gear kinematics and pitch-line velocity constraints, this paper conducts a minimum mass design study for several PGT / ECVT arrangements. Here, three different single stage PGT/ECVT arrangements are compared along with an improved two stage ECVT. The three single stage ECVT configurations can be summarized as; I) Sun-Engine / Carrier-Motor / Ring-Out, II) Sun-Engine / Ring-Motor / Carrier-Out, and III) Carrier-Engine / Sun-Motor / Ring-Out. Of these three types, it was found that type III was significantly lighter in weight compared with types I and II since type III would have the highest relative motor speed. When sized for a 3000 Hp engine-side power input at 6000 rpm, the minimum mass design for type III was on the order of 100 lbs compared to 400 lbs and 700 lbs respectively for types I and II. Despite the seemingly obvious advantage of design type III, it's drawback is that it is effectively a speed increasing stage with respect to the engine. To address this, a two-stage ECVT with compound planetary arrangement of Type III and II was designed which achieved an overall minimum weight of 219 lbs at the 3000 Hp level while providing 1:0.351 gear reduction form engine to output. The analysis tools developed and sizing results flowing from this study will provide a baseline for evaluating performance benefits and weight penalties introduced by parallel hybrid drive-systems for rotorcraft applications.
DeSmidt, Hans, Ai, Zhisheng
Dynamics of a Variable Speed Hybrid-Electric Helicopter Propulsion SystemF-0080-2024-12525/7/2024
In this paper, a comprehensive dynamic simulation of a parallel hybrid gas-electric single main rotor helicopter involving a motor/generator (MG) pair and a differential planetary gear transmission (PGT) arrangement forming an electronic continuously variable transmission (E-CVT) was performed. This notional hybrid electric helicopter was sized based on a retrofit of a dual engine, 10000 lb, 2500 Hp class helicopter. The total weight added by the electric components was 182 lbs which increased the propulsion system weight from 1184 to 1366 lbs. The simulation results found that at 110 kts cruise, the hybrid electric system enabled a 27% reduction in main rotor rpm which resulted in an 18% reduction in the fuel burn rate. It is concluded that use of an E-CVT parallel hybrid propulsion system offers potential for increased flight range and reduced fuel consumption in medium to large-scale helicopter applications.
DeSmidt, Hans, Ai, Zhisheng
Minimum Weight Design of a Two Speed Dual Clutch Offset Compound Gear Transmission for Rotorcraft ApplicationsF-0077-2021-168885/10/2021
ABSTRACT
DeSmidt, Hans, Ai,  Zhisheng
The Effect of Hub Moment on Main Rotor Shaft Drive GearsF-0077-2021-168865/10/2021
ABSTRACT
Binney, David, Hunte, Brian, Liu, Lin, Wright, Zach
Contact Pattern Development of the CH-53K MGB with Split-Path Gear-TrainF-0076-2020-1633310/5/2020
The US Marines CH-53K King Stallion replaces the venerable CH-53E Super Stallion and delivers almost triple the payload over the primary mission radius of 110 nm, while maintaining the same shipboard footprint. In order to achieve this the main gearbox design had to achieve an unprecedented power density. The main gearbox is a split torque gear box with three input clusters and four dual herringbone drive pinions per cluster. This paper addresses the challenges related to contact pattern development of the MGB 3rd-stage gear meshes.
He, Shulin, Leigh, Leslie, Gmiyra, Yryiy, Pierce, Chris
Modeling and Design of a Wet Clutch Offset Compound Gear Transmission for Dual-Speed Rotorcraft ApplicationsF-0076-2020-1633610/5/2020
This paper develops a lumped-parameter multi-plates wet clutch Offset Compound Gear (OCG) transmission dynamics and its thermal model for dual-speed rotorcraft applications with an active clutch slip-speed control. This model includes the Reynolds equation for the clutch oil film thickness, the clutch thermal model, the clutch transferred torques (viscous and asperity torque) and the clutch disengagement model. The wet clutch/OCG transmission system is implemented in Matlab® Simulink™ to manage the upshift clutch temperature rise, which is a main issue need to handle for a dual-speed helicopter transmission. Here, the clutch temperature rise is treated by injecting a certain amount of coolant during engagement so that the temperature rise for the wet clutch is much lower than that of an dry clutch. In order to transfer a required torque using the available power, the sizing of the wet clutch could be evaluated via the developed wet clutch/OCG transmission model. This study shows that the temperature rise drops as the wet clutch oil flow rate increases adding extra weights compared with the dry clutch. The simulation also captures a phenomenon that a larger clutch engagement pressure might be required for the wet clutch to transfer the same torque since the wet clutch oil viscosity drops as the oil temperature increases during the clutch engagement.
DeSmidt, Hans, Bill, Robert, Su, Xiaowen, Smith, Edward
Test Procedure for Parking Stability of MotorcyclesJ1101_202009 (Current)9/9/2020
Side stands and center stands are designed to support stationary two-wheel motorcycles. This SAE Standard establishes procedures for determining parking surface loading and stability limits as follows: a The footprint pressure exerted on a horizontal parking surface by the stand. b The tilt angle of the parking surface at which tip-over occurs. c The tilt angle of the parking surface at which roll-off occurs.
Motorcycle Technical Steering Committee
Modeling, Validation and Control Strategy Development of a Hybrid Super Sport Car Based on Lithium Ion Capacitors2020-01-04424/14/2020
Today, the contribution of the transportation sector on greenhouse gases is evident. The fast consumption of fossil fuels and its impact on the environment have given a strong impetus to the development of vehicles with better fuel economy. Hybrid electric vehicles fit into this context with different targets, starting from the reduction of emissions and fuel consumption, but also for performance and comfort enhancement. Lamborghini has recently invested in the development of a hybrid super sport car, due to performance and comfort reasons. Aventador series gearbox is an Independent Shift Rod gearbox with a single clutch and during gear shifts, as all the single clutch gearbox do, it generates a torque gap. To avoid the additional weight of a Dual Clutch Transmission, a 48V Electric Motor has been connected to the wheels, in a P3 configuration, to fill the torque gap, and to habilitate regenerative braking and electric boost functions. This paper discusses the usage of a control-oriented vehicle and powertrain model to analyze the performance of the first Lithium Ion Capacitor-based hybrid V12 by Automobili Lamborghini. The internal combustion engine, the gearbox, the LiC and the vehicle longitudinal dynamics models have been initially validated through the comparison with experimental data from chassis dynamometer testing, in addition to experimental results from specific components’ testing. As shown in the paper, the validated model has then been used to develop control strategies aimed at increasing comfort and performance, but also to expand the hybrid system capabilities by widening the LiC working range, and to study the possibility of implementing CO2 reduction-oriented control functions.
Franceschi, Alessandro, Cavina, Nicolo, Parenti, Riccardo, Reggiani, Maurizio, Corti, Enrico
Development of GM Allison 10-Speed Heavy Duty Transmission2020-01-04384/14/2020
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
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
An FxLMS Controller for Active Control Engine Mount with Experimental Secondary Path Identification2020-01-04244/14/2020
Active engine mounts (AEMs) notably contribute to ensuring superior performance of vehicle’s noise, vibration, and harshness. This paper incorporates a filtered-x-least-mean-squares (FxLMS) controller into the active control engine mount system to attenuate the transmitted force to the body. To avoid the error caused by substituting the load cell for acceleration transducer, the FIR model of the secondary path was obtained by experiment. Finally, a hardware-in-the-loop testing system is built to verify the performance of the active engine mount. It can be observed from the test results that the vibration is reduced notably after control, which demonstrates the effectiveness of the active engine mount and the controller in vibration attenuation.
Guo, Rong, Zhou, Ziwei, Chen, Hao
Development of a Component Level Test Methodology to Validate the Transmission Bush of a Manual Gear Box2020-01-14094/14/2020
In the era of fierce competition, launching a defect free product on time would be the key to success. In a modern automobile, the transmission system is designed with utmost care in order to transfer the maximum power from engine to driveline smoothly and efficiently. Optimized design of all the transmission components is necessary in order to meet the power requirement with the least possible weight. This optimization may require gear designs with different internal diameters. The assembly of these gears may not be possible on a solid transmission shaft. To facilitate assembling while retaining optimum design of transmission parts, a separate bush is designed to overcome this limitation. Some bushes may require a flange to restrict any free play of the mounted gear in its axial direction. During complete system level testing of one newly developed manual transmission, bush failure was observed. Bushes are generally press fitted on the transmission shafts, on which the needle roller bearing is mounted. In some cases, the free axial movement of the gear is restricted by the hub or shaft itself. But in other cases, due to assembly constraints, the bush itself is flanged to restrict the axial free play of the gear. When the respective gear is not in engaged condition, the bush does not get any axial thrust. Once the gear is engaged, due to the axial thrust caused by the helical gear, the bush experiences a certain amount of axial thrust. This axial thrust was suspected to be the reason of failure. A component level test set up maintaining the boundary condition was made and axial load was applied on the bush using a hydraulic actuator. The failure mode was simulated consistently, and design modifications were carried out. Modified designs were also tested using the newly derived test methodology and the modified design with the required durability life was adopted for implementation. The complete system level durability test was again performed with the modified bush and no failure was reported thereafter. The component level test methodology helped to test a number of design iterations and a number of samples within a stipulated time and cost. This methodology can be used in all future projects as a part of front-loading support before performing complete system level test.
Kathrecha, Devanshu, Chakraborty, Abhirup, Sirur, Avinash, Sebastian, Jobin, Savla, Jinesh
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
Real-time and Accurate Estimation of Road Slope for Intelligent Speed Planning System of Commercial Vehicle2020-01-01154/14/2020
In the intelligent speed planning system, real-time estimation of road slope is the key to calculate slope resistance and realize the vehicles’ active safety control. However, if the road slope is measured by the sensor while the commercial vehicle is driving, the vibration of the vehicle body will affect its measurement accuracy. Therefore, the relevant algorithm is used to estimate the real-time slope of the road when the commercial vehicle is driving. At present, many domestic and foreign scholars have analyzed and tested the estimation of road slope by the least square method or Kalman filter algorithm. Although the two methods both can achieve the estimation, the real-time performance and accuracy still need to be improved. In this paper, for traditional fuel commercial vehicle, the Kalman filter algorithm based on the kinematics and the extended Kalman filter algorithm based on the longitudinal dynamics are respectively used to estimate the road slope. In the process of estimation based on kinematics, considering the influence of road slope rate to estimate, the recursive least squares method with forgetting factor is used to estimate the road slope rate.Finally, the estimation results obtained by kinematics and dynamics are combined. It is expected that the error based on the algorithm-estimated slope value and the true slope value will be within 6% after the commercial vehicle is driving. The proposed algorithm has high accuracy, good real-time performance and strong stability. Using the commercial vehicle as a motion node and estimating the slope of a certain road, the intelligent planning of other vehicles’ speed in that region can be realized through the cloud platform. Then the fuel economy of the commercial vehicle can be improved.
Zhou, Mi, Tan, Gangfeng, Sun, Meng, Tian, Zhongpeng, Zhou, Fangyu, Liu, ZhiQiang
Research on Control Strategy Optimization for Shifting Process of Pure Electric Vehicle Based on Multi-Objective Genetic Algorithm2020-01-09714/14/2020
With more and more countries proposing timetables for stopping selling of fuel vehicles, China has also issued a “dual-slope” policy. As electric vehicles are the most promising new energy vehicle, which is worth researching. The integration and control of the motor and gearbox have gradually become a hot research topic due to low cost with better performance. This paper takes an electric vehicle equipped with permanent magnet synchronous motor and two-gear automatic transmission without synchronizer and clutch as the research object. Through the action of the motor, gearbox and shift actuator in the shifting process, the whole vehicle dynamics is modeled in each stage of shifting, a method for determining a short-term driving style intensity factor for decision shifting is proposed, three evaluation indexes of the shift quality of electric vehicle are put forward, the control parameters affecting the shift quality are analyzed, and the mathematical relationship between the shift control parameters, the shifting time and the shifting impact are obtain. Besides, the NSGA-II algorithm is used to carry out multi-objective global optimization of the whole process of shifting to get Pareto optimal solution. Analyze the optimization results in combination with driving style, determine some thresholds and parameters of the drive motor and shift actuator action control during the shifting process, improve the shift control strategy, and finally complete the coordinated control of the shifting process of the electric drive system based on the active synchronization of the motor. The results show that the optimization effect is good. It provides a new idea for the shifting process control of the pure electric vehicles.
Lei, Yulong, Zhang, Jingxu, Fu, Yao, Jia, Fuchun, Wang, Binyu
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
Optimized Wet Clutch Design2019-32-05531/24/2020
Multi-plate wet clutches used in motorbikes transmit the torque by friction under pressure between driving and driven Plates. The life & performance of the clutch for the friction material used, depends on amount of energy generated during clutch slip, amount & uniformity of heat dissipation amongst the plates and surface texture of mating surfaces. Above parameters if not properly considered during design stage may lead to higher temperature of rubbing surfaces. Higher temperature further reduces the friction coefficient and increases the wear rate of friction material leading ultimately to lower torque capacity of clutch. The temperature rise in a wet clutch is the balance between amount of heat generated and the amount of heat dissipated by oil flowing through clutch. The maximum amount of oil is limited by the requirement of clutch drag torque, Which decides the quality of neutral finding and gear shift feel on vehicle. Further, if roughness of rubbing surfaces is not controlled in mass production, it leads to fast wear of friction material during initial operating cycles. The rate of wear is faster if the heights of surface asperities are of high magnitude. This paper explains the design features of clutch developed by Endurance Technologies Ltd., optimized to achieve above aspects, for the engines having clutch cooling oil supply through the gear box input shaft. I. An innovative oil management concept is incorporated which distributes the oil as per requirement amongst the plates. Adequate distribution of oil facilitates to have optimum oil flow with minimum desired drag torque. It also ensures effective heat dissipation throughout the clutch assembly. A part of oil is directed to cool the clutch clamping springs which reduces the clamping load loss. II. The validation procedure to confirm the adequacy of oil flow through the plurality of plates is developed. III. The defined controlled surface texture of steel plates provides consistent and controlled wear rate in mass production. Further, it ensures the dynamic torque capacity within a narrow band over the longer life span. The above two features of multi-plate wet clutch design achieved reduction in wear by 56 % and improved dynamic torque capacity by 16 % at the end of durability tests.
Bhone, Nitin, Thakare, Sachin, Jahagirdar, Ashutosh
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
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
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
Editorial19AVEP11_0111/1/2019
After digesting some of the fascinating insights from surveys taken of automated-vehicle test riders - most of them first-timers - who participated in SAE International's Demo Days program (see pg. 31), you've got to conclude that the only thing predictable about the new-mobility landscape is its unpredictability. The year's not over yet and already it's been a wild ride.
Visnic, Bill
Fault Detection in Single Stage Helical Planetary Gearbox Using Artificial Neural Networks (ANN) and Decision Tree with Histogram Features2019-28-015110/11/2019
Drive train failures are most common in wind turbines. Lots of effort has been made to improve the reliability of the gearbox but the truth is that these efforts do not provide a lifetime solution. Majority of failures are caused by bearing and gearbox. It also states that wind turbine gearbox failure causes the highest downtime as the repair has to be done at Original Equipment Manufacturer [OEM]. This work aims to predict the failures in planetary gearbox using fault diagnosis technique and machine learning algorithms. In the proposed method the failing parts of the planetary gearbox are monitored with the help of accelerometer sensor mounted on the planetary gearbox casing which will record the vibrations. A prototype has been fabricated as a miniature of single stage planetary gearbox. The vibrations of the healthy gearbox, sun defect, planet defect and ring defect under loaded conditions are obtained. The signals show the performance characteristics of the gearbox condition. These characteristics and their number of occurrences were plotted in a histogram graph. Predominant statistical features which represent the fault condition were selected using decision tree algorithm. Using these features the Artificial Neural Network (ANN) and J48 algorithms were trained and tested to classify the faults. The accuracy of the machine learning algorithm greatly helps in deciding the optimum time to carry out the required maintenance operation.
Shaul Hameed, Syed, Vaithiyanathan, Muralidharan, Kesavan, Mahendran
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
New-generation Nissan Versa breaks for higher ground19AUTP10_1410/1/2019
Subcompact cars hardly are spotlight-grabbers at the moment, but Nissan's nonetheless delivered up an all-new 2020 Versa that notches higher fuel economy, quicker acceleration, tighter S-curve poise and a quieter cabin compared to the outgoing Versa. “Nissan's third-generation Versa is well-balanced in terms of performance, handling, and ride comfort,” Jose Romo, the car's marketability engineer, told Automotive Engineering during a recent media ride-and-drive program in Nashville, Tenn.
Buchholz, Kami
Modelling and Control of a Novel Clutchless Multiple-Speed Transmission for Electric Vehicles2019-24-00639/9/2019
Conventional electric vehicles adopt either single-speed transmissions or direct drive architecture in order to reduce cost, losses and mass. However, the integration of optimized multiple-speed transmissions is considered as a feasible method to enhance EVs performances, (i.e. top speed, acceleration and grade climbing), improving powertrain efficiency, saving battery energy and reducing customer costs. Perfectly in line with these objectives, this paper presents a patented fully integrated electric traction system, as scalable solution for electrifying light duty passenger and commercial vehicles (1.5-4.2 tons), with a focus on minibuses (<20 seats). The adoption of high-speed motor coupled to multiple-speed transmission offers the possibility of a relevant efficiency improvement, a 50% volume reduction with respect to a traditional transmission, superior output torque and power density. The proposed clutchless four-speed transmission is specifically conceived and designed to have the good matching with the traction electric motor. Indeed, clutches and synchronizers are not required thanks to the small inertia of the traction motor and its fast regulation in both torque and speed mode (torque modulation process). Therefore, an advanced shifting control system/strategy has been developed to reduce the time shifting, linked to the degree of jerk and the power interruption, guaranteeing the coordination of all the gear-shifting actuators despite the randomness of the gear shifting process. After the description of the system layout, the paper gives an insight of the plant dynamic model and its equations. The controller architecture along with its strategies are also presented. The effectiveness of the proposed solution is proven through an extensive set of simulations carried out for a vehicle running on a real driving cycle.
Malafronte, Ludovica, Grandone, Mauro, Lega, Alberto, Pennese, Michele, Pianese, Cesare
ZF shifts EV transmission efficiency up a gear19AUTP09_129/1/2019
ZF Project Engineer Volker Vogel checked that the Lausitzring test track ahead was clear and announced: “Now from stationary on full throttle.” From the rear of the prototype van came the almost instant and familiar whine of a very busy electric motor as the speed built. Then, the unexpected: A slight change in volume at 70 kph (44 mph) as the transmission shifted to a second gear. “It is only at prototype stage.” Implicit in Vogel's words was the need to make allowances. But that was not necessary; as shifters go, this is a real smoothie.
Birch, Stuart
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
Experimental Investigation on Gear Rattle Noise Reduction in Passenger Car2019-01-15616/5/2019
Gear rattle noise reduction inside the passenger cabin is one of the major challenges for customer comfort enhancement. Therefore, it becomes a prime target during transmission design and development. Gear rattle is generated due to meshing teeth collision of free gears, which is caused due to torsional vibration of engine transferred through clutch. Vibrations are generated due to free gears teeth impact and are transferred to shaft, bearings and transmission housing. The sound absorption and structural vibration of transmission housing was optimized by changing the geometrical features of the transmission housing that affects radiated noise. Experimental approach for gear rattle noise reduction through transmission housing modification is described in this paper. Moreover, CAE method is also incorporated with the experiments for optimization of future vehicle transmission system designs.
Khare, Devendra Kumar, Vaishya, Abhishek Lakhanlal, Pujara, Archan Sunibhai, Krishna, Radhe, Satpathy, Kingshuk, Choudhary, Ved Prakash, Pandey, Anant
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
Investigation on Cyclic Noise in Vehicle Creeping during Stop-Go Traffic Conditions2019-01-15576/5/2019
Now-a-days, customers are turning more sensitive towards vehicle NVH performance. In order to enhance customer NVH comfort, a specific noise phenomenon was investigated during product development. While testing stop-go traffic conditions, cyclic noise was observed in the 1st gear with the vehicle creeping. The noise was similar to a gear rattling noise. It was perceived unpleasant due to low background noise and wide frequency range of cyclic noise. This paper explains the root cause of this cyclic noise through various drivetrain experiments and also elaborates the experimental analysis approach in order to arrive to the solution in gear and clutch design for cyclic noise elimination.
Vaishya, Abhishek Lakhanlal, Pujara, Archan Sunibhai, Khare, Devendra Kumar, Satpathy, Kingshuk
Gear BearingsTBMG-345786/1/2019
NASA Goddard Space Flight Center developed gear bearing technology that combines gear and bearing functions into a single unit that significantly improves gear drives for electrical, internal combustion, and turbine motors. The gear bearing design incorporates rifle-true anti-backlash, improved thrust bearing performance, and phase-tuning techniques for superior low-speed reduction. Because it combines gear and bearing functions, it reduces weight, number of parts, size, and cost, while also increasing load capacity and performance.
An Optimal Gear Shifting Strategy for Minimizing Fuel Consumption Based on Engine Optimum Operation Line2019-01-50555/21/2019
The increasing numbers of vehicles with limited fossil fuel resources, on the one hand, and the growing level of stringent regulations on exhaust emissions, on the other hand, have galvanized automotive industries and researchers into developing solutions for more efficient vehicles. Notwithstanding the recent developments in powertrain technologies, driving behavior is still an important attribute in lowering fuel consumption. Gear shifting strategy is a staple aspect of driving behavior that affects fuel consumption and engine emissions to a large extent in both manual and automated transmission systems. According to the definition of Optimum Operating Line (OOL), this article intends to illustrate that the closer the engine operating points to the OOL, the more efficient the driving. An optimal gear-shifting strategy is presented to minimize fuel consumption and number of gear shifts while maximizing drivability in the new European driving cycle (NEDC). In order to limit the engine operating region close to the OOL, a multi-objective grid search method is used to design the two square-root-like curves (two shifting thresholds), on both sides of the OOL, in the engine Brake Specific Fuel Consumption (BSFC) map. The results show a 4% reduction in fuel consumption and a 6% increase in the driving performance when using the square-root-like shifting boundaries compared with using RPM-constant shifting boundaries.
Nikzadfar, Kamyar, Bakhshinezhad, Nima, MirMohammadSadeghi, S. Ali, Taheri Ledari, Hossein, Fathi, Alireza
Swept Volume Approach for the Characterization of Pumping Loss of Shrouded Meshed Cylindrical GearsF-0075-2019-146815/13/2019
High speed rotorcraft transmissions are subject to load-independent power losses consisting of drag and pumping loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load independent losses. However, tightly conforming axial shrouding can result in an increase in the pumping loss component. Quantifying the pumping loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating pumping loss based on the concept of swept volume borrowed from the positive displacement pump and compressor industry. In this study, pumping loss of shrouded gear transmissions is considered to be related to the swept volume of the gear sets and the downstream flow resistance created by the shroud clearances. The drag loss and pumping loss of a spur gear pair have been determined through testing using the NASA Glenn Research Center Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. Good correlation exist between the test pumping power loss and the predicted pumping power loss for tightly conforming axial shroud configurations.
Hurrell, Michael, Delgado, Irebert
Parametric Instability of Planetary Gear Transmission with Elastic Ring Gear due to Discrete Boundary Strut Parameter VariationF-0075-2019-146675/13/2019
This paper investigates the effects of different boundary strut parameters on parametric instabilities of planetary gear transmission (PGT) driveline system with elastic ring gear over the whole operating speed range. As an example, to demonstrate the PGT system boundary strut design, an optimal design strategy is briefly introduced not only to obtain a light-weight system, but also to satisfy the stress and buckling conditions of the boundary struts. Assumed-modes method is used to discretize the system and Floquet method is applied to the established PGT driveline system with elastic thin ring gear supported by discreate boundary struts to explore the parametric instabilities of the PGT system due to different boundary strut parameter variations. The results show that by properly selecting the boundary strut parameters, the parametric instabilities of the PGT driveline system can be avoided or shifted. Therefore, vibrations of the PGT system introduced by the parametric excitations can be suppressed correspondingly.
Guan, Peng, DeSmidt, Hans
Dynamic Simulation of Diagonal Shift Assist System in Transmission2019-01-05394/2/2019
In a car with a Manual Transmission, Gear Knob is the main touch point for the driver to interact with vehicle control system. Therefore, Gear Shift Quality of vehicle is very important from customer point of view. With growing competition, even in a cost sensitive market like India, importance of the gearshift quality of manual transmissions has increased significantly over the past few years. In Manual Transmission, shift tower is a system to assist the driver during selecting and shifting of gears. Diagonal Shift Assist (DSA) is a part of shift tower, which guides the gear shift from 5th gear to 4th gear and act as a safety device to prevent 5th to reverse gear engagement. The dynamic interaction of DSA system in shift tower is difficult to interpret by traditional test methods and virtually impossible at concept stage. To overcome these difficulties a dynamic model of the entire Shift Tower mechanism i.e. shift select lever, 3D ramp, detent pin, spring, interlock mechanism and DSA has been created. The model predicts the effectiveness of DSA system in smooth shifting of 5th to 4th and prevention of 5th to reverse gear shift. The model can then be used for parameter studies to investigate potential improvements in DSA system. This paper will present experience of simulation of DSA system in shift tower using a dynamic model in ADAMS software, the structure of the model, methodology used and correlation with testing results
Singh, Bhupinder, Choudhary, Ved Prakash
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
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
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
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
GKN demos eTwinster 2-speed, torque-vectoring BEV transmission19AUTP04_114/1/2019
GKN Automotive unveiled what it claims is the world's first 2-speed, torque-vectoring transmission for battery electric vehicles (BEVs). Featured on GKN's 2019 Technology Demonstrator (GTD19)-a Jeep Renegade-based prototype-the EV-enhancing tranny was revealed to media during GKN's annual winter testing program in Arjeplog, Sweden. Combining several advances in GKN's driveline technologies, the coaxial eTwinster transmission could improve BEV efficiency as well as straight-line and handling performance. The new 2-speed “seamless shift” eTransmission has the potential to extend vehicle range while also providing increased torque for improved acceleration and a higher top speed, all while using smaller electric motors. Efficiency and further powertrain downsizing are enhanced by the eTwinster's coaxial layout, while improved stability and dynamic performance are possible thanks to its torque-vectoring capabilities.
Seredynski, Paul
Generation of Optimized Rotation of Counterweights from Balancing Device for Slider-Crank Mechanisms2019-01-50203/26/2019
The main purpose of this work was to minimize the total unbalanced inertial forces generated by slider-crank mechanism during steady-state regime, developing the concept behind the Lanchester balancer. The goal approach was based on a kinematic scheme, which realizes conversion of the input crankshaft steady speed into a prescribed output speed of counter-rotating weights. The needed adaptability of output rotation speed was obtained through theoretical model of noncircular gear transmission. The dynamic result consisted in generating balancing forces that should have acquired optimized instantaneous magnitudes. A mathematical model of the required device was built and analytical investigation was performed in order to obtain geometrical features of gears. This mathematical approach supplied an exact solution for potential employment into the kinematic scheme. At this point a review of feasibility of obtained results was done. The scarcity of practical utility of previously obtained results requested another strategy to get to the target. Consequently the main problem was reformulated as Evolutionary Multi-objective Optimization (EMO) problem. Optimization method was based on Genetic Algorithms (GA) and lead to the best compromise that produced a numerical result entered into Computer-Aided Design (CAD) routines, for modelling of noncircular gears constituting the needed system. The open-source evolutionary computation library MOEA Framework was set as the work environment. It supports a variety of Multi-objective Evolutionary Algorithms, including GA, Genetic Programming, and Particle Swarm Optimization. These tools were applied in different tests in order to gain the most efficient way of optimization. NSGA-II was revealed experimentally as most appropriate algorithm. At the end of this study we do a practical employ of NSGA-II together with CAD implementations for synthesis of solid models. The overall benefit of resultant balancing action was estimated as 89% reduction in peak-to-peak amplitude of dynamic load.
Destradi, Giovanni
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
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
2019 Toyota RAV4: Doubling down on a best-seller19AUTP02_172/1/2019
To say the RAV4 is a crucial product for Toyota might be underselling it. In the U.S., the 5-seat, 5-door FWD/AWD midsize SUV has become Toyota's best-selling vehicle, the nation's best-selling non-pickup truck and the best-selling vehicle in its class. The market's SUV sway is also apparent in RAV4, as its annual sales volume has doubled in the last five years, cresting 400,000 in 2017. According to Yoshikazu Saeki, Rav4's chief engineer, his team spent the last four years working to ensure each version of the all-new 2019 RAV4 felt more confident and responded more naturally to driver input. “It sounds simple,” Saeki said, “but getting the intent of the driver to match the action of the vehicle is difficult to implement.”
Seredynski, Paul
Selection of Rational Parameters of Automated System of Robotic Transmission Clutch Control on the Basis of Simulation Modelling2019-01-00291/15/2019
The article deals with the analysis of one of the methods of selecting rational parameters of automated clutch control system for robotic transmission. The objective is to select rational parameters of automated clutch control system for robotic transmission, equipped with electropneumatic actuating mechanism on the basis of mathematical simulation. The depicted mathematical simulation of the clutch control system is characterized by the possibility to coordinate the algorithm of control unit with the dynamic processes in the execution device. The new functional interrelations between the elements of the electro-pneumatic actuator are mathematically described. The way to the selection of rational parameters of an automated control system for clutch is recommended; the selection taking into account the features of the electro-pneumatic actuator. Using the mathematical modeling method, rational control parameters of the automated clutch control system are determined. Based on comparative experimental researches, an inaccuracy is calculated for the mathematical modeling of the processes taking place in the electro-pneumatic actuator of a robotic transmission. Analysis of the results of mathematical modeling allowed finding factors that give a competitive advantage in comparison with automated clutch control systems that are used for commercial purposes.
Mikhalevich, Mykola, Yarita, Alexandr, Leontiev, Dmitry, Gritsuk, Igor V., Bogomolov, Viktor, Klimenko, Valeriy, Saravas, Viktoriya
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