Browse Topic: Continuously variable transmissions

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A Power Split eCVT Hybrid for Sustainable Urban Mobility2024-32-002904/18/2025
The main drivers for powertrain electrification of two-wheelers, motorcycles and ATVs are increasingly stringent emission and noise limitations as well as the upcoming demand for carbon neutrality. Two-wheeler applications face significantly different constraints, such as packaging and mass targets, limited charging infrastructure in urban areas and demanding cost targets. Battery electric two wheelers are the optimal choice for transient city driving with limited range requirements. Hybridization provides considerable advantages and extended operation limits. Beside efficiency improvement, silent and zero emission modes with solutions allowing fully electric driving, combined boosting enhances performance and transient response. In general, there are two different two-wheeler base categories for hybrid powertrains: motorcycles featuring frame-integrated internal combustion engine (ICE) and transmission units, coupled with secondary drives via chain or belt; and scooters equipped with
Schoeffmann, W., Fuckar, G., Hubmann, C., Gruber, M.
Technical Paper
Regression Test 08/22/24 - Tatsiana twrtwtwSAE-PP-0944808/22/2024
QA Test
Mutagaana, Festo
Pre-Print Article
Optimization of Energy Management Strategy for Multi-Mode Hybrid Transmission Based on Condition Prediction2023-01-703210/30/2023
Since there are no typical working conditions in the field of engineering vehicles, this paper implements the construction of driving conditions based on Markov stochastic model and energy management strategy of a multi-mode hybrid mine dump truck based on dynamic programming algorithm under this background. Firstly, on the basis of existing vehicle driving data, we calculate the velocity transfer probability matrix with the Markov stochastic model, and then construct the vehicle driving condition after predicting the velocity. The constructed working conditions are applied to the energy management strategy of dynamic programming algorithm to calculate the energy consumption of the hybrid mining truck. It is proved that this construction method can be applied to the hybrid electric mine dump truck, and the DP based energy management strategy has lower energy consumption.
Jiang, Y.T., Zhao, Xinxin, Zhang, J.G.
Technical Paper
A High Efficiency Transmission Architecture for Electric Vehicles2022-01-079203/29/2022
A Dual Epicyclic Electronic Continuously Variable Transmission (DE-ECVT) with an input-split, output coupled, split-power-path configuration is proposed for improving overall system efficiency and range for electric vehicles. By modulating the power split ratio between the mechanical (i.e. Planetary Gear Trains) and electrical drivelines (i.e. Motor Generator Units), a continuous range of gear ratios that facilitate a higher efficiency powertrain is obtained. The proposed concept leverages two power-split units that leads to significantly reduced power flow through the electrical drivelines (compared with single speed EV transmissions as well as single power-split E-CVTs) while providing the same overall ratio spread for transmission operation. A multi-layered optimization is performed, first on the operational control strategy to maximize the end-of-cycle SOC (State of Charge) of the battery for a given set of transmission design parameters, and then subsequently on the design
Swain, Anshuman, Gopalswamy, Swaminathan
Technical Paper
Model Based Evaluation of Parallel Hybrid Concepts for a Scooter for Reduced Fuel Consumption and Emissions2022-01-080803/29/2022
IC engines are most efficient when they operate steadily in specific zones which cannot be attained in real driving conditions. Hybrids tackle this issue and improve drivetrain efficiency. Though they are used in cars and commercial vehicles they do not find application in small two wheelers especially scooters which constitute the majority of the market in several Asian Countries. The reasons are cost of implementation and need to have a suitable design. Integrating an electric motor with a conventional scooter drivetrain while retaining the base engine and the CVT is a cost effective proposition which is the motivation behind this work. Such a development will need accounting for the behavior of the belt driven CVT. In this paper a comparison between two parallel hybrid layouts has been made with the base 110cc scooter powertrain. A map based engine model and a physics based CVT model were developed and validated to simulate the base drive-train on the WMTC drive-cycle. A rule based
Mathivanan, Arulkumaran, Elango, Pradeev, Kakani, Raghav, Das, Himadri B, Ramesh, A
Technical Paper
Local change of PV value on end faces of rocker pins of chain type CVT (Continuously Variable Transmission) under transmitting condition2022-32-005301/09/2022
The objective of this study was to investigate the local change of PV value on the end faces of rocker pins driven by a high-performance chain under transmitting torque conditions. A test bench system was prepared to evaluate the behavior of the chain belt under driven state. Local contact force of the pin was measured by strain gauges attached to a specific modified pin for which the thickness was partly reduced by machine work. Change of PV value on the end face of the pin was also calculated by considering the change of pressure generated by contact force and sliding velocity of rocker pin. Autorotation angles of the rocker pins in the groove of driving and driven sheaves were investigated by replacing the normal pulleys with visibly transparent sheaves made with acrylic resin. The representative loading points were also calculated assuming that the pin was regarded as a simple beam where an eccentric compressive load was applied. Test results showed that slight bending deformations
Kikui, Ryunosuke, Obunai, Kiyotaka, Okubo, Kazuya, Toyohara, Kouhei, Watanabe, Kyohei, Jin, Hui
Technical Paper
A Simplified Computational Fluid Dynamics Approach for Optimizing a Continuously Variable Transmission Casing2021-01-124009/21/2021
The Continuously Variable Transmission (CVT) is a popular form of automotive transmission that uses friction between a belt and pulley to transmit power. Due to the sliding and other losses associated with the belt, power is lost in the form of heat, which must be dissipated to enhance the belt‟s life. The task of heat dissipation is, however, complicated by the use of a CVT casing, which serves to protect the transmission from mud, debris, etc. Consequently, the design of an optimum CVT casing for efficient cooling is a challenging task. Experimental approaches or 3D numerical simulation approaches to tackling such problems are either involved or time-consuming or both. This article discusses a novel and simplified strategy for optimizing a CVT casing for maximum heat removal, using computational fluid dynamics (CFD). The rotating pulleys are approximated as heated, rotating cylinders inside a two-dimensional flow domain of the casing. Transient CFD calculations are carried out on a
Sharma, Ayush, Mittal, Aakrit, Tanwar, Harshit
Technical Paper
Mathematical Modeling of the Longitudinal motion of a Vehicle with a Continuously Variable Transmission2021-01-123709/21/2021
The Continuously Variable Transmission (CVT) is a widely adopted transmission system. It varies smoothly across a range of gear ratios and provides an automatic transmission. The operation of a CVT is simple, but successfully foretelling the longitudinal motion of a vehicle that utilizes such a transmission mechanism is sophisticated. As a result, different vehicles taking part in BAJA-SAE competitions were developed using various strategies to model the vehicle’s longitudinal dynamics and CVT operation. This article aims to provide a tool for obtaining a quantitative estimate of the longitudinal performance of a CVT-equipped vehicle and for the selection of an optimal drive-train gear ratio for such a vehicle. To this end, this article proposes a novel, relatively simple, and reasonably accurate mathematical approach for modeling the longitudinal motion of a vehicle utilizing a CVT, which was developed by a novel integration of existing vehicle dynamics concepts. The proposed
Sharma, Ayush, Tanwar, Harshit, Mittal, Ankit
Technical Paper
New Holland extends ag lineup with CH7.70 combine, T6 ‘multitasker’ tractorSAE-MA-0459703/12/2021
The full-line brand targets “harvesting supremacy” with the debut of a new Crossover Harvesting technology that increases throughput.
Gehm, Ryan
Magazine Article
WHAT WE'RE DRIVING21AUTP02_0802/01/2021
Since its U.S. launch for the '18 model year, the positioning of the Kicks has puzzled me. Though Nissan was anxious to bill it a “crossover,” I think most would call it a “car.” Nissan hardly is alone in this marketing sleight-of-hand. Given American buyers' refusal to tarnish themselves with anything that can't be construed as some kind of truck, it's at least understandable. But here's my rule: no calling it a crossover if it can't be had with all-wheel drive. And confoundingly, inexplicably, stubbornly against all sense, the Kicks is strictly front-drive. Apart from that, the Kicks probably accomplishes some of the mission of grabbing buyers who need to think they're not purchasing a car; Nissan sold a comparatively healthy 58,858 Kicks in 2020.
Magazine Article
Energy Efficiency of Vehicles with Combined Electromechanical Drive of Driving Wheels2020-01-226009/15/2020
In this paper the use of a combined electro mechanical drive for driving wheels of vehicles make it possible to realize potential of a stepless transmission. In this case, the use of various differential mechanisms that summarize the movement from the internal combustion engine (ICE) and the electric motor can reduce the unevenness in time of the traction force on the drive wheels. Improving energy efficiency of hybrid vehicles is also possible by ensuring the engine operation at a constant high-speed mode. In tis paper the results of evaluating the reduction of energy losses during acceleration of the vehicle and the engine at constant speed. The use of continuously variable transmission (variator, electric and electromechanical transmission) along with other advantages allows the engine to operate at a constant angular speed. In this case, when accelerating a car, energy is saved due to the absence of its costs for accelerating the rotating masses of the engine. For cars, 4-6% of
Podrigalo, Mikhail, Bogomolov, Viktor, Kholodov, Mykhailo, Koryak, Alexander, Turenko, Anatoliy, Kaidalov, Ruslan, Verbitskiy, Victor, Nikorchuk, Andrey, Volodarets, Mykyta, Kudimov, Serhii, Khodyriev, Serhii
Technical Paper
Coordination Control Strategy for Mode Switching of a Parallel Hybrid Electric System Based on Continuously Variable Transmission02-13-02-001008/11/2020
This study aims to solve the problem of impact in a parallel hybrid electric system based on the continuously variable transmission (CVT) during switching from pure electric mode to engine-driven, power-generating mode. Taking into account the torque response characteristics of the engine and motor and the dynamic characteristics of the wet clutch hydraulic control system, the mode switching process is divided into six stages, namely, pure electric mode, wet-clutch free travel, engine start-up, engine speed synchronization, clutch combination, and engine intervention drive. A coordination control strategy is developed based on the model predictive control algorithm to ensure smooth mode switching. The effectiveness of the control algorithm is verified using Matlab/Simulink and the AMESim co-simulation platform. Results show that with the mode switching coordination control strategy, the components of the system work harmoniously. The maximum impact is reduced by 52.0% at the speed
Zeng, Xiaohua, Li, Xiaojian, Dong, Bingbing
Journal Article
WHAT WE'RE DRIVING20AUTP08_0707/01/2020
Before I started a drive in the 2020 Mazda3, I had to toggle the drive-select to “sport.” And release the parking brake. Each and every time. At least the two switches are in proximity on the center console. But this annoyance mars the generally good experience of the Mazda3 (all-new in 2019) and once again suggests it's a refreshing but occasionally cockeyed prism through which Mazda engineers and planners view the world.
Magazine Article
Maximum Sound Level Potential for MotorcyclesJ47_202006 (Current)06/05/2020
This SAE Recommended Practice establishes the test procedure, environment, and instrumentation for determining the maximum sound level potential for motorcycles under wide open throttle acceleration and closed throttle deceleration.
Motorcycle Technical Steering Committee
Recommended Practice
Dynamics and Control of Gearshifts in Wet-Type Dual Clutch Transmission for BEVs2020-01-076704/14/2020
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
Lou, Zhenxiong, Duan, Yupeng, Zhang, Yunqing
Technical Paper
Analysis of CVT Element Vibration by In-Situ Measurement2020-01-090604/14/2020
When the belt of a metal pushing-belt CVT is wrapped around the pulleys, vibration is said to be generated from the friction force caused by the elements that make up the belt rubbing against each other. In order to verify this, a small data logger with a triaxial accelerometer (G Sensor) was developed in house, then fixed on a side surface of a movable pulley and measurements were conducted at engine speeds characteristic of actual driving (1500-2500 rpm). The measurement results showed that there is a difference between the average radius of the belt when it is wrapped around the pulley and when it is not wrapped around the pulley, demonstrating that vibration is occurring.
Matsumoto, Kenji, Koga, Hideharu, Saito, Toshihiro, Mihara, Yuji
Technical Paper
Main Features of Forming the Transmission of an Active Multi-Link Road Train2020-01-042704/14/2020
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
Belousov, Boris, Haritonchik, Sergey, Keller, Andrei, Bakhmutov, Sergey, Berdnikov, Alexey, Alyukov, Sergei, Alyukov, Alexander
Technical Paper
Two-Speed Transmission Gear Shift Process Analysis and Optimization Using Genetic Algorithm08-09-01-000101/16/2020
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
Cao, Zhan, Yang, Jiansen, Wang, Xinyu
Journal Article
Dynamic modeling and simulation of a powertrain system with a six-speed automatic transmission2019-36-010001/13/2020
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
de Araujo, Marcel T. da S., Falleiros, Murilo F., Gioria, Gustavo dos S.
Technical Paper
Spring and Damper Tuning of an ATV to Reduce Transmissibility2019-28-240111/21/2019
The application in vehicle ride and handling has been mostly subjective or intuitive. There are several methods to improve vehicle stability and handling. One of the methods is suspension tuning. The objective of this work is to perform dynamical analysis of suspension by spring and damper tuning to reduce transmissibility for an all-terrain vehicle. A baseline spring rate data is used for tuning to provide better ride. The Fox air shock absorbers with progressive damping are used for testing. First the dynamics simulation is carried out by using ADAMS CAR tool. A detailed characteristic of the air shocks is obtained at various loading conditions by experimentation using test rig. Based on it, the simulation has been carried out for desired tuning parameters of spring and damper to improve stability. The speculated optimum setting is validated on an all-terrain vehicle (ATV) using ultrasonic sensors, by varying vehicle speed and bump heights to evaluate the transmissibility of the
Kanade, Rajat Girish, Agrewale, Mohammad Rafiq, Vora, Kamalkishore
Technical Paper
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
Recommended Practice
Hybrid Transmission for Optimizing Input Machine Operation08-08-02-000811/14/2019
The hybrid transmission with a single energy source is presented in this article, which has the ability to, under certain constraints, transfer the energy from the input shaft with arbitrary variable speed onto the output shaft with the variable speed required for an output machine or propelling member operation - without a control system. The transmission is in a way similar to a power-split transmission for hybrid electric vehicles sans the battery and a power-split control logic. Development of a dedicated control system enables the optimal operation of the input machine. As an example, the transmission is designed for a passenger automobile. For the chosen automobile type, the power train is modeled in MATLAB/Simulink. In drive simulations during the single New European Driving Cycle (NEDC), the powertrain efficiency and fuel consumption are obtained and compared with two comparable vehicles: the conventional one and the advanced HEV. The competitiveness of the proposed
Jelaska, Damir, Perkušić, Milan, Podrug, Srdjan, Tvrdić , Vjekoslav
Journal Article
MOMENTUM: OCTOBER 201919MOMP1010/01/2019
Advanced Class Starship Georgia Tech team right on the mark with glider-deploying RC aircraft at SAE Aero Design competition. 75 points Much more time and energy go into a Formula SAE Presentation Event than one might think. Major redesign A new electronic CVT highlighted a year of major vehicle upgrades for the historically strong Baja SAE team from ETS.
Magazine
WHAT WE'RE DRIVING19AUTP10_0710/01/2019
What first impresses about the GT is how easy it is to drive. Ingress is a little tricky over the wide sill, but once situated in the comfy driver's seat you use a strap to position the foot controls to your liking in a very cramped pedal box, and you have a few degrees of seatback angle to play with. The 3.5-L EcoBoost twin-turbo-charged V6 erupts to life from what feels like just behind your right earlobe, but settles quickly in a buzzing idle. Like many competition-focused machines, the V6 has a lightened-crank eagerness about it, but the “automatic” gearbox prevents any uneasiness about getting underway. Thanks to the rear-wheel-drive GT's low and centered mass, the engine can mutter away at low rpm while easily bringing the GT up to traffic speeds.
Magazine Article
Innovative Dedicated Hybrid Transmission Concepts in the Next Generation of Hybrid Powertrains08-08-01-000509/20/2019
Due to the advantages of hybrid vehicles in comparison with pure electric vehicles, Hybrid Electric Vehicle (HEV)/Plug-in HEV (PHEV) no undoubtedly becomes the reasonable and practical solution in the development of vehicle electrification at the moment. Meanwhile, Dedicated Hybrid Transmission (DHT), as the especially designed hybrid transmission for HEV/PHEV, represents the development direction of hybrid vehicles. But in the market, the well-known DHT concepts are all protected by patents by large Original Equipment Manufacturers (OEMs). How to break the patents and more importantly develop the innovative DHT concepts in the next generation is of vital importance in the development of HEV/PHEV. In this article, firstly, the features and comparisons of different well-known DHT concepts are discussed and analyzed. The mechanical and electrical complexity are introduced to essentially analyze the advantage and disadvantage of different kinds of DHT concepts. Based on the analysis, the
Chen, Haijun, Li, Lin, Lange, Andreas, Küçükay, Ferit
Journal Article
Innovative Dedicated Hybrid Transmission Concepts in the Next Generation of Hybrid Powertrains08-08-01-0005-TEST-REC09/20/2019
Due to the advantages of hybrid vehicles in comparison with pure electric vehicles, Hybrid Electric Vehicle (HEV)/Plug-in HEV (PHEV) no undoubtedly becomes the reasonable and practical solution in the development of vehicle electrification at the moment. Meanwhile, Dedicated Hybrid Transmission (DHT), as the especially designed hybrid transmission for HEV/PHEV, represents the development direction of hybrid vehicles. But in the market, the well-known DHT concepts are all protected by patents by large Original Equipment Manufacturers (OEMs). How to break the patents and more importantly develop the innovative DHT concepts in the next generation is of vital importance in the development of HEV/PHEV. In this article, firstly, the features and comparisons of different well-known DHT concepts are discussed and analyzed. The mechanical and electrical complexity are introduced to essentially analyze the advantage and disadvantage of different kinds of DHT concepts. Based on the analysis, the
Chen, Haijun, Li, Lin, Lange, Andreas, Küçükay, Ferit
Journal Article
Ford amped for new phase of hybrid-electric offensive19AUTP06_1206/01/2019
With the persistent auto-industry question of how soon battery electric vehicles will become mainstream options, Ford is preparing to widely deploy its fourth-generation hybrid-electric vehicle (HEV) technology that Dave Felipe, the VP of powertrain engineering, said will result in a fuel-efficient, performance-rich HEV variant for “all mainstream models” in North America. The company's wide-ranging plan to implement hybridization is a central aspect of its commitment to invest $11 billion in new electrification technology by 2022, said Felipe. He added that the new modular hybrid technology (MHT) system for its larger and heavier vehicles that often are used for towing makes Ford “the only OEM that's going to play in those places” with hybrid models-while market forces sort out how quickly electric vehicles are adopted for mass-market buyers.
Visnic, Bill
Magazine Article
Modeling of the Automatic Power Distribution System among the Traction Motors of the Driving Wheels of a Multi-Axle Vehicle2019-01-091404/02/2019
Dynamics of acceleration, mobility, fuel efficiency of wheeled vehicles are largely determined by the drive circuit to the driving wheels and bridges, as well as devices used in drive link nodes to distribute power among the driving wheels. This is especially important for multi-axle wheeled vehicles. In this paper, the object of the study is a multiaxial wheeled vehicle with an electric transmission consisting of an internal combustion engine with a power of 720 kW, one common generator and twelve traction motors mounted directly on the driving wheels. In connection with the change in load on the driving wheels due to the variability of soil properties, driving conditions (acceleration, braking, uniform motion), terrain topography, it is necessary to provide external regulation of electric machines working in the transmission of the vehicle. The aims of the work are: 1) the study of currents and voltages in traction motors while changing the properties of the ground during the
Kondakov, Sergei, Pavlovskaya, Olga, Aliukov, Sergei, Smirnov, Vladimir
Technical Paper
Coordinated Mode Transition Control for a Novel Compound Power-Split Hybrid Electric Vehicle2019-01-130604/02/2019
Because of the direct connection between the compound power split hybrid transmission (CPSHT) and the engine in hybrid electric vehicle (HEV), engine ripple torque (ERT) can lead to obvious jerks when the mode transition from electric driving mode to hybrid driving mode occurs. In order to enhance the riding comfort, two additional wet clutches are mounted in this novel CPSHT and the relevant coordinated control strategy is developed. Firstly, after the description of the mechanical and hydraulic parts of the novel CPSHT, the dynamic plant model including driveline model, engine ripple torque and clutch torque is deduced. Secondly, the mode transition process in the original and current designs are compared and analyzed with the equivalent level diagram and the encountered problems are stated. Thirdly, a coordinated control strategy is designed to determine the target motor torque, clutch torque, engine torque, and the moment of fuel injection based on the second-order sliding mode
Shen, Dengfeng, Guehmann, Clemens, Zhang, Tong
Technical Paper
Optimization of the Process of Acceleration of a Vehicle Taking into Account the Regimes of Operation of Its Engine2019-01-077604/02/2019
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
Ulanov, Alexander, Aliukov, Sergei
Technical Paper
Lexus soups-up seventh-generation ES sedan18AUTP11_1011/01/2018
Sedans and any configuration of a “car” might be a tough sell at the moment, but Toyota's Lexus division certainly wasn't going to let that stop it from launching a new, seventh generation of the ES midsize sedan, which by a large margin just happens to be the brand's best-selling car (51,398 last year in a shrinking U.S. market for sedan bodystyles). The ES typically accounts for nearly half of Lexus' total car sales. Considering that kind of sales critical mass, it's tough to say the ES has been injured by its reputation as being the softer “cruiser” of the Lexus car lineup, but the company seems to continually strive to inject more sporting character into the midsize sedan. Such is the case with the new 2019 ES-there are two variants, the ES350 with a 3.5-L V6 and the ES300h hybrid that went on sale in the U.S. in September-although refinement and isolation remain at the expected high levels.
Visnic, Bill
Magazine Article
Super Low Viscosity ATF; AW-22018-01-175609/10/2018
Reducing loss torque in automatic transmissions (ATs) is a key factor in improving fuel economy. A promising approach is to reduce the viscosity of the Automatic Transmission Fluid (ATF) so as to minimize churning loss. Aisin AW and JXTG Nippon Oil & Energy Corporation have developed a super low viscosity ATF, called “AW-2”, which has approximately 50% lower kinematic viscosity at 40 °C compared to the conventional ATF “AW-1”. It is generally understood that if the viscosity of an ATF is too low, it can have a negative impact on the fatigue life of components such as gears and bearings, and possibly lead to increased wear or seizure. AW-2 was designed to solve these problems via the application of two key technologies. The first is a high performance base oil with a low traction coefficient, which translates to low viscosity under high pressure conditions. This decreases the shear resistance between sliding surfaces under elastohydrodynamic lubrication (EHL) conditions, which
Masuda, Kohei, Nakao, Hajime, Komatsubara, Hitoshi, Kurosawa, Osamu, Yamada, Katsuhito, Ishikawa, Kazunori, Mori, Atsushi
Technical Paper
WHAT WE'RE DRIVING18AUTP09_0509/01/2018
Don't know how I overlooked the Chrysler Pacifica Hybrid for so long, but it gets my personal award for most pleasant- and pleasingly surprising-vehicle I'll drive in 2018. I expected an underwhelming, underpowered groaner of a hybrid and instead I got a super-efficient and fabulously smooth do-anything limousine. The Pacifica Hybrid owes most of its agreeable nature to the “eFlite” 2-motor electrically-variable transmission that works with virtually no noise, fuss or even gear-shifting sensation, freeing you from the blaring groan of the continuously variable transmission (CVT) typical to most hybrids. Its two integral motors, 84 hp and 114 hp each, channel the power from 16 kWh lithium-ion battery pack alone or in collaboration with the Atkinson-optimized 3.6-L V6.
Magazine Article
Transmission-Mounted Power Control Unit Including 12-Volt DC-DC Converter for Two-Motor Hybrid System2018-01-045704/03/2018
This research proposes a third-generation power control unit (PCU) for a two-motor hybrid system. To make a more compact intelligent power unit (IPU) to be located under the second seat, a PCU with a 12-volt DC-DC converter (DCDC) that mounts directly on the transmission was developed, whereas the DCDC was previously mounted within the IPU. Since this has a considerable impact on the engine room layout, the technology described below was used to make the PCU even more compact than the second-generation unit. The power module, a key component of the PCU, now uses Ag nanoparticles sintering bonding rather than conventional solder bonding. This helps lower thermal resistance and enables smaller power semiconductors. The voltage control unit (VCU) has a new circuit that uses a multi-stage switching circuit and electric power transfer capacitor instead of the conventional chopper circuit. This makes it possible to shrink the reactor to less than 65% of its usual volume without raising the
Ozuchi, Yasuhiro, Tomokage, Ryoji
Technical Paper
Nonlinear Hybrid Optimization for the Powertrain of a Four-Wheel-Drive (4WD) Vehicle2018-01-123004/03/2018
Lightweight of the structure is known as an effective approach to improve fuel economy and handling of the automobile. Moreover, the optimization for the powertrain increases the acceleration performance and reduces the energy consumption of driven components. In this paper, a popular powertrain of a Four-Wheel-Drive (4WD) vehicle is considered as a research object. The nonlinear hybrid mathematical model of optimization is created. The target function, whose value varies with continuous and discrete variables, is the combined moment of inertia consisting of transmission and sub-actuator. The constraints include the gear surface fatigue, gear bending fatigue, the belt tensile failure and so on. The design variable involves the sizes of gears and sheaves, the gear thickness, the numbers of sheaves and so on. Finally, some results based on the nonlinear programming principles are derived, and relative conclusions are drawn.
Wu, Huyao
Technical Paper
Dynamic Lever: Key to Automotive Transmission and Drivetrain Dynamics2018-01-116504/03/2018
Lever analogy has been developed for more than 30 years. The powerful tool can greatly simplify transmission analysis and has been widely used for transmission powerflow analysis, selection, and control synthesis. In the past two decades, automatic transmissions have undergone a rapid growth with continual increase in the number of speeds and electrification. The increase in the system complexity has presented great challenges to system integrations. Many unpredicted issues have been NVH related and difficult to troubleshoot, partially due to the lack of proper modeling and analysis tool to capture the drivetrain dynamics including transmission components. Although the lever analogy has played important roles in the system design, the current form is not adequate and has never been used for dynamic analysis for the transmission and drivetrain system. In this article, we will introduce the dynamic lever model framework and analysis method to address the dynamic aspect of a transmission
Li, Dongxu
Journal Article
Development of a Torque-Based Control Strategy for a Mode-Switching Hydraulic Hybrid Passenger Vehicle2018-01-100704/03/2018
An increase in the number of vehicles per capita coupled with stricter emission regulations have made the development of newer and better hybrid vehicle architectures indispensable. Although electric hybrids have more visibility and are now commercially available, hydraulic hybrids, with their higher power densities and cheaper components, have been rigorously explored as the alternative. Several architectures have been proposed and implemented for both on and off highway applications. The most commonly used architecture is the series hybrid, which requires an energy conversion from the primary source (engine) to the secondary domain. From he re, the power flows either into the secondary source (high-pressure accumulator) or to the wheels depending upon the state of charge of the accumulator. A mode-switching hydraulic hybrid, which is a combination of a hydrostatic transmission and a series hybrid, was recently developed in the author’s research group. This paper focuses on the
Banerjee, Pranay, Ivantysynova, Monika
Technical Paper
Inertial Continuously Variable Transmissions and Ways to Improve Their Performance2018-01-105904/03/2018
The inertial continuously variable transmissions are transmissions of mechanical type. They have a number of advantages in comparison with other types of transmissions. For example, they have a big value of the coefficient of efficiency, since the principle of their action does not imply the need to convert energy from one type to another one. These transmissions have a compact design, a wide range of torque transformation. They can operate in direct mode, smoothing the torsional vibrations in the system. At the moment when the output shaft is stopped, the input transmission shaft continues to rotate, that prevents the engine from overloading. There are other advantages. But despite these advantages, the inertial transmissions are not widely used in the automotive industry. The main reason for this is the inadequate durability of the freewheel mechanisms involved in the designs of the inertial transmissions. The paper considers some ways to improve the efficiency and durability of the
Aliukov, Sergei, Keller, Andrei, Alyukov, Alexander
Technical Paper
TECHNOLOGY DESIGNED TO WIN18MOMP02_0202/01/2018
École de technologie supérieure (ÉTS) student engineers developed an electronic continuously variable transmission that was the first of its kind used in Baja SAE competition. INNOVATION HAS ALWAYS BEEN A PART of our team spirit, something we share with the more than 25 other scientific clubs at the École de technologie supérieure (ÉTS) in Montreal. We designed our Baja SAE car with stunning aesthetics to turn heads, but also to stand out due to the highly complex technologies we incorporated. In 2017, we set a new bar by being the first team in the history of the Baja SAE to win a competition (California) using an electronic continuously variable transmission (CVT). It worked so well that we went on to win again at the Baja SAE Illinois event.
Magazine Article
MOMENTUM: FEBRUARY 201818MOMP0202/01/2018
The drive to success Gopher Motorsports at the University of Minnesota places special emphasis on reliability, with positive results ensuing. Technology designed to win École de technologie supérieure (ÉTS) student engineers developed an electronic continuously variable transmission that was the first of its kind used in Baja SAE competition. Big Data a focus for 2018 SAE President Mircea Gradu Velodyne CQO sees use of Big Data as a way to capitalize on multiple industry trends including vehicle electrification and automated vehicles.
Magazine
WHAT WE'RE DRIVING18AUTP02_1502/01/2018
It isn't every carmaker that introduces its new model with a session on a tight and slippery test track. But when it's a 1955-kg (4090-lb) sedan with 450 kW (603 hp) and 850 N·m (627 lb·ft) available at the shove of a foot, it is a useful education. That's what Mercedes-Benz offers its U.K. buyers of the new Mercedes-AMG E 63 S 4Matic+.
Magazine Article
DANA OPENS NEW CHAPTER ON CVTs18AUTP01_0401/01/2018
A dedicated development center is hustling the unique VariGlide “spherical traction drive” toward 2020 production. Any emerging technology that warrants its own dedicated development center-40,000 ft2, staffed by 40 engineers and loaded with state-of-art design engineering, analysis, metallurgy, machining, prototyping and test cells with four dynamometers-must be considered a competitive threat. That's the buzz within the powertrain community about Dana's Cedar Park, TX, tech center, and the highly anticipated VariGlide continuously-variable planetary transmission under development there since 2014. VariGlide is slated to enter production at one or more light vehicle OEMs in 2020. Dana engineers claim it will offer up to 10% greater fuel efficiency than incumbent CVTs, with improved drivability and NVH characteristics. It is “highly scalable” according to company engineers and its compact design enables it to effectively slot into existing transmission housings without significant
Brooke, Lindsay
Magazine Article
Testing and Benchmarking a 2014 GM Silverado 6L80 Six Speed Automatic Transmission2017-01-502011/17/2017
As part of its midterm evaluation of the 2022-2025 light-duty greenhouse gas (GHG) standards, the Environmental Protection Agency (EPA) has been acquiring fuel efficiency data from testing of recent engines and vehicles. The benchmarking data are used as inputs to EPA’s Advanced Light Duty Powertrain and Hybrid Analysis (ALPHA) vehicle simulation model created to estimate GHG emissions from light-duty vehicles. For complete powertrain modeling, ALPHA needs both detailed engine fuel consumption maps and transmission efficiency maps. EPA’s National Vehicle and Fuels Emissions Laboratory has previously relied on contractors to provide full characterization of transmission efficiency maps. To add to its benchmarking resources, EPA developed a streamlined more cost-effective in-house method of transmission testing, capable of gathering a dataset sufficient to broadly characterize transmissions within ALPHA. This technique targets the range of transmission operation observed during vehicle
Stuhldreher, Mark, Kim, Youngki, Kargul, John, Moskalik, Andrew, Barba, Daniel
Technical Paper
Continuously Variable Transmission (CVT) Fuel Economy2017-01-235510/08/2017
Due to its simplicity and fuel economy benefit, continuously variable transmission (CVT) technology has gained a lot of attention in recent years. Market penetration of CVT technology is increasing rapidly compared to step-type automatic transmission technology. OEMs, Tier 1 suppliers, and lubricant suppliers are working to further improve the fuel economy benefit of CVTs. As a lubricant supplier, we want to understand the effects of fluid properties on CVT fuel economy (FE). We have formulated fluids that had KV100 ranges from 2-4 cSt to 7-9 cSt with various types and viscosities of base oils. Wide ranges of viscosity indexes, steel-on-steel friction, and other properties were tested. Full vehicle fuel economy tests were performed in a temperature controlled environment with a robotic driver. The test revealed that there was more than 3% overall FE variation compared to a reference fluid. Iron content analysis following each test confirmed there was no noticeable transmission wear
Kwak, Yungwan, Cleveland, Christopher
Technical Paper
Driveline Ratio Selection and Shift Map Optimization for Automatic Transmission Vehicle at Concept Phase through Simulations06-11-01-000510/08/2017
Traditionally driveline ratios are selected based on trial and error method of proto vehicle testing. This consumes lot of time and increases overall vehicle development effort. Over last few decades, simulation-based design approach has been extensively used to alleviate this problem. This paper describes torque converter and final drive ratio (FDR) selection at concept phase for new Automatic Transmission (AT) vehicle development. Most of the critical data required for simulating vehicle performance and fuel economy (FE) targets were not available (e.g. shift map, clutch slip map, pedal map, dynamic torque, coast down, etc.) at an initial stage of the project. Hence, the risk for assuming right inputs and properly selecting FDR/Torque converter was particularly high. Therefore, a validated AVL Cruise simulation model based on an existing AT vehicle was used as a base for new AT vehicle development to mitigate the risk due to non-availability of inputs. The simulation model shows 97
Paulraj, Srinivasan, Muthiah, Saravanan
Journal Article
Composition Platform for Conventional and Hybrid Powertrains2017-24-017209/04/2017
In view of the rapidly increasing complexity of conventional as well as hybrid powertrains, a systematic composition platform seeking for the global optimum powertrain is presented in this paper. The platform can be mainly divided into three parts: the synthesis of the transmission, the synthesis of the internal combustion engine (ICE) and the optimization and evaluation of the entire powertrain. In regard to the synthesis of transmission concepts, a systematical and computer-aided tool suitable both for conventional und hybrid transmissions is developed. With this tool, all the potential transmission concepts, which can realize the desired driving modes or ratios, can be synthesized based on the vehicle data and requirements. As a result of the transmission synthesis, the detailed information of each transmission concept, including the transmission structure, the shifting logic, the estimated efficiency in each gear, and the estimated space arrangement of the transmission can be given
Chen, Haijun, Li, Lin, Schudeleit, Mark, Lange, Andreas, Küçükay, Ferit, Stamme, Christian, Eilts, Peter
Technical Paper
Automotive Transmission TerminologyJ645_201708 (Historical)08/25/2017
The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.
Automatic Transmission and Transaxle Committee
Recommended Practice
Infinitely Variable Transmissions Using a Toroidal Traction Variator Web Seminar RePlayPD331709ON07/11/2017
An Infinitely Variable Transmission (IVT) is a subset of a CVT (Continuously Variable Transmission) defined as a device that has a range of ratios of input shaft speed to output shaft speed which includes an Infinite ratio in which the output speed is zero. Typically these devices include both positive and negative ratios on either side of zero resulting in the ability to move forward and reverse from rest without a clutch: IVTs can improve vehicle performance while maintaining or exceeding benchmark functionality and performance. IVTs are a good candidate for future, fuel-efficient vehicles, particularly hybrids and AWDs. An IVT can maintain superb functionality and performance while reducing fleet CO2 levels. No vehicles other than heavy tractors currently use IVT transmissions. A number of companies have looked at implementing IVT but they have failed to find an economical solution with sufficient upside to warrant its introduction, despite the attractive functional benefits. The
eLearning
Electric Baggage/Cargo TractorARP1804B (Current)06/09/2017
This SAE Aerospace Recommended Practice (ARP) outlines the design and performance requirements for a battery-powered electric tow tractor for the handling of baggage or cargo trailers in airline service. The use of “shall” in this document indicates a mandatory requirement. The use of “should” indicates a recommendation or that which is advised but not required.
AGE-3 Aircraft Ground Support Equipment Committee
Recommended Practice
Inertia Continuously Variable Transmissions and Investigation of their Dynamics2017-01-110303/28/2017
The inertial continuously variable transmission is a mechanical transmission which is based on the principle of inertia. This transmission has a lot of advantages, namely: compactness, minimum friction losses and high efficiency as a result of the relatively small number of rotating components, a wide range of transformation of the torque. It does not need any conventional friction clutches. This transmission protects the engine from overload when the output shaft is braked. This drive guarantees optimum conditions of work for the engine regardless of the changing of load, and smoothly changes output speed according to the load. Mostly, design of this transmission consists of a pulsed mechanism with unbalanced inertial units and two overrunning clutches. The objects of the investigation are structural dynamic analysis of the continuously variable transmission. The physical and mathematical models of this transmission are developed. For these models of the transmission the differential
Aliukov, Sergei, Keller, Andrei, Alyukov, Alexander
Technical Paper
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