Browse Topic: Transaxles
Oil seal leakage is one of the major failure mode in gearbox / transaxle. Oil seal failures can be due to various reasons like high temperature, insufficient lubrication, failure due to external environment, incorrect fitment etc. Major reason for oil seal failure is insufficient oil flow inside gearbox when vehicle is running on gradient for long duration. When vehicle is running in hilly region, transmission will get incline leading to oil deficiency at one half of the transmission. Oil seal in this location will not get sufficient lubrication and will run dry. Also, there will be rise in local temperature at seal lip to shaft interface leading to failure of oil seal lip. Subsequently, oil leakage from transmission will start from this location when vehicle is running in different terrain. Due to continuous seepage, oil quantity in the transmission will get reduced and may lead to gear failure or seizure of bearing. Some OEM use transmission with transparent housing for lubrication study to get vital information on sufficiency of lubrication at critical parts at different inclinations of transmission (simulating driving of vehicle in different terrain). Such study does not provide clear idea about endurance life of oil seals and other parts under certain extreme / critical driving conditions. This paper discusses the test schedule & methodology developed to simulate oil flow inside gearbox as per real world driving scenarios on test bench and to evaluate endurance life of oil seal under such conditions. To develop the test procedure rigorous road load data need to be done at vehicle level. During this vehicle need to be driven in various road mix conditions like mines, rough road, hilly terrain in forward and reverse gear for few hundred kilometers and vehicle level and powertrain level data is recorded with help of commercially available sensors and data loggers. Test procedure need to be derived after data analysis to have test schedule for simulating real world condition on test bench. Process briefed in this paper will help to reduce development time & cost.
Recently, electric-powered vehicle such as HV, PHV, EV and FCV has been highly demanded and getting attention due to the increase of environmental-consciousness. Also, environmental regulations are getting more and more strict in many countries and regions. Then, environmental friendly vehicle is needed to be spread more and more than ever. As it is found in “TOYOTA Environmental challenge 2050”, Toyota will rapidly increase the number of new car sales of electric-powered vehicle towards 2050. This paper covers the rear wheel drive Q710 electric drive transaxle for 2nd generation MIRAI FCV. Toyota developed the transaxle for FCV (rear mounted) and for EV (front mounted) simultaneously and achieved coexistence of vehicle mountability and commonization of majority of the parts. This paper describes the hardware feature and the detailed technology which was adopted to Q710. In the 2nd generation MIRAI, the transaxle is mounted under rear floor and contributed to the improvement of drivability by rear wheel drive. In addition, two air-cooled oil cooler are placed in parallel behind transaxle for motor cooling. Based on the adoption of world’s first “differential pressure wind guide oil cooler”, Toyota succeeded in motor cooling by the air-cooled oil cooler which is placed to rear.
Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will introduce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure.
This paper presents about new concept developed on 7 speed DCT transaxle for transverse application and a torque capacity of 200 Nm to 360 Nm. How current 6 speed DCT can modified to 7 speed with packaging benefit is discussed. In this paper, discussions are focused about torque carrying parts of transaxle only. Here only single countershaft is used giving lot of packaging advantage and at first glance layout looks like four speed layout, but it is compact layout. Further in this paper effect of angular position of shaft in layout is discussed. Position of shafts in transaxle layout effects the stress, bending moment and displacement induced in shaft. Detailed study on effect of change in angle with respect to Bending moment, Stress in shaft, Cylindrical roller bearing (CRB) and Deep Groove Ball Bearing (DGBB) Bearing reaction force analysis, life calculations are computed.
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.
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.
The new P710 hybrid transaxle for a mid-size 2.5-liter class vehicle was developed based on the Toyota New Global Architecture (TNGA) design philosophy to achieve a range of desired performance objects. A smaller and lighter transaxle with low mechanical loss was realized by incorporating a new gear train structure and a downsized motor. The noise of the P710 transaxle was also reduced by adopting a new damper structure.
BorgWarner's modular strategy provides OEMs optimal electrified-driveline flexibility. Five years ago, few predicted the high level of technology fragmentation in powertrains, drivelines and fuels that exists in 2017. Nearly everyone now agrees, however, that hybridization of all types is essential to meeting the latest European, North American and Asian emissions regulations-and to connect to the long-term full-electric future. Whenever that comes. “We see it as a ‘spectrum of electrification’ from stop-start systems all the way to pure EV-and everything's in play,” observed John Barlage, Director of Product Strategy, of BorgWarner PowerDrive Systems. Like other Tier 1 powertrain systems planners, he sees “very large volumes” of 48V hybrid applications coming in the next (2019-2021) production cycle.
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.
The reduction of CO2 emissions at vehicle level through the improvement of transmission efficiency represents the essential goal of transmission development engineers. New requirements, such as the recovery of the kinetic energy of the vehicle while coasting, the hybridization of drivetrains and autonomous driving, are challenges that can best be overcome with automatic transmissions. Dual clutch transmissions (DCT) with power-on-demand actuation systems offer a particularly efficient method of meeting the new requirements. However, many markets show vehicle applications with production volumes of less than 100.000 units per year. FEV’s new DCT family is conceived especially for customers in these markets. The re-use of proven subsystems which are already in series production results in a "business case" for applications with lower volumes also. This article introduces this transmission family.
GM has developed an all-new gasoline-electric hybrid powertrain for the model year 2016 Chevrolet Malibu Hybrid vehicle, which was designed to achieve excellent fuel economy, performance, and drive quality. The powertrain shares the transmission architecture with the 2016 Chevrolet Volt extended range electric vehicle, but includes changes to optimize the system for engine driven charge sustaining operation in the range of conditions represented by the US EPA 5 cycle fuel economy tests. In this paper, we describe the Malibu Hybrid propulsion system features and components, including the battery pack, transaxle, electric motors and power electronics, engine, and thermal system. The modifications between the Volt and Malibu Hybrid propulsion systems are discussed and explained as resulting from the differences between the primarily electric and gasoline powered applications. Additionally, operation of the propulsion system under nominal and cold fuel economy driving conditions is explained, and we present and discuss the efficiency and performance benefits and results of the new propulsion system.
1 As the demand for so-called eco-cars has been increasing recently, new hybrid transaxle P610 has been developed to achieve outstanding fuel economy and an excellent driving performance. P610 was installed in the 4th generation Prius, the first car to implement TOYOTA's new development strategy, TNGA (Toyota New Global Architecture). In order to accomplish the goal, radical reduction of mechanical loss, size and weight, dual-axle motor structure are adopted to draw out the potential capability of the THS (Toyota Hybrid System) to the maximum extent possible. Furthermore, placing the compact power train low, which is realized by installed the PCU(Power Control Unit) on top of the transaxle, led to provide the low center of gravity of the vehicle and excellent driving performance.
Primary function of a drive half shaft is to transfer torque from transaxle to the wheels in East West configuration powertrain vehicles. Conventional practice is to consider either 1st gear max torque or the Wheel slip torque, whichever being the maximum as design torque. However vehicle dynamics and Powertrain characteristics have a major influence on the Driveshaft torque and the torques experienced can thus go beyond the design torque. This questions the design endurance limit for the driveshaft based on conventional design. One such situation is the torque experienced by the driveshaft during vehicle coasting condition with gear downshift. The torque experienced in such a scenario can go beyond the maximum design torque leading to failure as was observed in Vehicle level validation test. The paper mainly discusses about modelling such a scenario theoretically by a system approach to the vehicle test phenomenon and evaluating the torque pre-emptively to redefine the design torque strategy. Variables required for the calculation were identified and their values were determined using the engine and vehicle characteristics. Furthermore driveshaft torque measurement was done on the test vehicle with strained gauge shaft and telemetry to study the effect of variables and to refine the model based on measurement data. Finally a co-relation between the calculated torque values and measured torque was done to understand the level of accuracy.. Modifications were also done to the part and bench test was done to understand the level of improvement.
The powersplit transaxle is a key subsystem of Ford Motor Company's hybrid electric vehicle line up. The powersplit transaxle consists of a planetary gear, four reduction gears and various types of bearings. During vehicle operation, the transaxle is continuously lubricated by a lube oil pump. All these components consume power to operate and they contribute to the total transaxle losses which ultimately influences energy usage and fuel economy. In order to enable further model-based development and optimization of the transaxle design relative to vehicle energy usage, it is essential to establish a physics-based transaxle model with losses distributed across components, including gears, bearings etc. In this work, such a model has been developed. The model accounts for individual bearing losses (speed, torque and temperature dependency), gear mesh losses, lube pump loss and oil churning loss. The losses are implemented as physics based equations as opposed to 2D or 3D table data, to enable smooth acausal simulation. Required bearing loss data are initially obtained from bearing suppliers. To aid the model development process, transaxle spin loss and torque loss tests were conducted. The test data was used to calculate unknown component loss information. The developed model was calibrated to match the transaxle test data. The model was also validated through comparison of dynamometer test data with vehicle level fuel economy simulations of the standard EPA City, Highway, US06 and FTP20 drive cycles and detailed energy analysis.
The Chevrolet Volt is an electric vehicle (EV) with extended-range (ER) that is capable of operation on battery power alone, and on power generated by an on-board gasoline engine after depletion of the battery charge. For 2016, GM has developed the next generation of the Volt vehicle and “Voltec” propulsion system. Building on the experience of the first generation Volt, the second generation targeted improved all-electric range, improved charge sustaining fuel economy, and improved performance. All of this was to be accomplished while maintaining the EV character of the first generation Volt which customers clearly valued. This paper describes the next generation “Voltec” system and the realized improvements in efficiency and performance. The features of the propulsion system components, including energy storage, transaxle, electric motors and power electronics, on-board charging, and engine are described and compared with the previous generation. Next, the transaxle powerflow is discussed and operation under typical driving conditions is explained. Finally, system efficiency and performance data, based on component tests, is presented and compared with the previous generation. This system includes a battery pack with greater energy density, a new transaxle with integrated power electronics and motors, and an engine with optimized displacement, direct injection, and other advanced features. As a result of these improvements, the second generation Volt vehicle is projected to achieve a 30% increase in EV range, an 11% improvement in charge sustaining label fuel economy, and improved vehicle performance both as an electric vehicle, and in extended range mode.
This research developed a new measurement technology for thermal analysis of the heat radiation from a hybrid transaxle case surface to the air and improved the heat radiation performance. This heat flux measurement technology provides the method to measure heat flux without wiring of sensors. The method does not have effects of wiring on the temperature field and the flow field unlike the conventional methods. Therefore, multipoint measurement of heat flux on the case surface was enabled, and the distribution of heat flux was quantified. To measure heat flux, thermal resistances made of plastic plates were attached to the case surface and the infrared thermography was used for the temperature measurement. The preliminary examination was performed to confirm the accuracy of the thermal evaluation through heat flux measurement. The oil in the transaxle was heated and the amount of heat radiation from the case surface was measured. The input energy and heat radiation amount were compared. As a result, it was found that the measurement was accurate to be within about 13%. In addition, thermal analysis with conditions simulating an actual vehicle was performed. The surface temperature distribution and heat flux distribution were measured and results were obtained that reflected the effects of internal oil flow path layout and cooling air flow. Based on these results, locations with a large potential for improved heat radiation performance were identified and it became possible to effectively improve heat radiation performance by installing fins at those locations to enlarge the heat radiation surfaces.
Finding space for an electric motor, battery, and all the controls that go with them while still providing sufficient 5-passenger cabin room and trunk/luggage capacity is a challenge. Space fiction has become part of some auto companies' description of hybrids. Finding space for an electric motor, battery, and all the controls that go with them while still providing sufficient 5-passenger cabin room and trunk/luggage capacity is not easy. And that means the hybrid versions of some sedans suffer in useful cargo space. But at Oerlikon Graziano, Claudio Torrelli, Head of Product Development, says far better packaging can be achieved. And to demonstrate it, the company recently fitted a Mercedes-Benz SLS AMG with its new OGeco transmission that integrates a 120-kW (161-hp) electric motor within the same space as a conventional transmission. The integration saw the electric motor installed deep in the gearbox and changing of the layout of the gearbox itself. The OGeco transmission is a 2-shaft configuration with one secondary shaft, whereas the dual-clutch (DCT) is a 3-shaft with two secondary shafts.
The General Motors (GM) 1ET35 drive unit is designed for an optimum combination of efficiency, performance, reliability, and cost as part of the propulsion system for the 2014 Chevrolet Spark Electric Vehicle (EV) [1]. The 1ET35 drive unit is a coaxial transaxle arrangement which includes a permanent-magnet (PM) electric motor and a low loss single-planetary transmission and is the sole source of propulsion for the battery-only electric vehicle (BEV) Spark. The 1ET35 is designed with experience gained from the first modern production BEV, the 1996 GM EV1. This paper describes the design optimization and development of the 1ET35 and its electric motor that will be made in the United States by GM. The high torque density electric motor design is based on high-energy permanent magnets that were originally developed by GM in connection with the EV1 and GM bar-wound stator technology introduced in the 2Mode Hybrid electric transmission, used in the Chevrolet Volt and in GM eAssist systems. The 1ET35 transaxle provides high power density and low system loss over a wide speed range, resulting in a class-leading combination of vehicle performance and vehicle range on a variety of global drive cycles.
A new performance simulation capability has been developed for powersplit HEVs to enable analytical assessment of new engine technologies in the context of HEV system operation and to analyze/understand important system dynamics and control interactions affecting HEV performance. This new capability allows direct simulation with closed-loop controls and the driver, is compatible with Ford standard HEV system simulation capabilities and enables simulation with multiple levels of model fidelity and feature content across the vehicle system. The combined plant Vehicle Model Architecture (VMA) in Simulink was used for the infrastructure. The simulation capability includes a Dymola model of the powersplit transaxle, a Vehicle System Control (VSC) model implemented in Simulink, a high fidelity 2L Atkinson GT-Power engine model, and a simplified representation of the engine controls in Simulink. Also, the simulation capability interfaces to Ford standard vehicle data sets for HEVs through a Matlab interface. A GT-Power Fast Running Model (FRM) for the 2L Atkinson engine was also developed and used in the vehicle simulation in order to speed up the simulation time. The model results were validated with performance test data for the 2L Atkinson engine in a prototype Ford Fusion HEV.
Interlock mechanism have found multiple uses in the shift system of a manual transmission. It can either be used to block every other rail from moving other then the active shifting rail or it can be used to bring all rails in neutral positions. As a designer the aim is to make systems more compact and efficient in its functionality. This desire to have a compact shift system results in the design of an interlock ball mechanism which allows the use of a single shift finger for two different rails. To validate this design a 5 speed manual transaxle was used, in which the 5th rail and the reverse rail are combined in a single shift finger. Between the rails a single 8mm interlock ball is used to transmit the shifting force to the rails from the shift finger. After a complete analysis of the profile for every degree of gradient the model was manufactured for testing on bench setup established for shifting tests. Various tests were performed and the system was tested and validated. Thus this system helps the designer to make the use of single shift finger for movement on two different rails without the use of a detent mechanism to centralize the rails. This system makes the shift mechanism cheaper, more compact and effective.
The first commercially available Plug-In Hybrid Electric Vehicle (PHEV), the General Motors (GM) Volt, was introduced into the market in December 2010. The Volt's powertrain architecture provides four modes of operation, including two that are unique and maximize the Volt's efficiency and performance. The electric transaxle has been specially designed to enable patented operating modes both to improve the electric driving range when operating as a battery electric vehicle and to reduce fuel consumption when extending the range by operating with an internal combustion engine (ICE). However, details on the vehicle control strategy are not widely available because the supervisory control algorithm is proprietary. Since it is not possible to analyze the control without vehicle test data obtained from a well-designed Design-of-Experiment (DoE), a highly instrumented GM Volt, including thermal sensors, was tested at Argonne National Laboratory's Advanced Powertrain Research Facility (APRF). In this paper, we first describe the vehicle instrumentation and the test results. The vehicle control algorithm is analyzed from the test data and designed in Simulink. Finally, the Autonomie Volt component models and control strategy are validated, using APRF vehicle test data.
Manual transmissions are characterized by gear ratios that are selectable by locking selected gear pairs to the output shaft inside the transmission. Top gear is selected to get a maximum speed and is limited by the engine power, speed and the fuel economy. Lower gears are selected to get maximum speed at maximum gradient. Lower gears are also expected to give creeping speed to avoid usage of clutch and brake in city traffic. Selection of intermediate gears is such that it provides a smoother gear shift. Gear spacing is done in geometric progression. Spacing between the higher gears is usually closer than in the lower gears because drivers shift more often between the lower gears. This is opposed to the conventional idea of progressive spacing where higher gears had more space between them. An objective method is provided for selecting gear ratios for use in vehicle transmission having multiple selectable gears. The method includes selecting gear ratios for a specific application followed by calculating a low gear ratio and a high gear ratio based upon vehicle parameters and performance requirements. The total ratio spread is determined by dividing the low gear ratio by the high gear ratio. Using the total ratio spread a geometric sequence is created with a plurality of terms, such that each of the terms respectively represents the ratio steps between the gears. Lastly, each gear ratio is divided by its respective ratio step plus one to find the gear ratio for the next gear. This method provides an objective method for selecting gear ratios, such that the steps between each of the ratios are uniformly progressive. Not only the procedure is generalized and validated but also a performance prediction tool is developed in house for quick validation and results. The theoretical gear ratio thus calculated was formulated and made using ROMAX as indicated in fig. 1. Thus, for a range of torques different gear boxes like 5 MT- 320Nm transmission, 6MT transmission, 6MT transaxle, 5MT-100Nm were tested. Performance prediction for vehicles with the designed gear ratios was rigorously done and required parameters were recorded and compared. An experience with the wide range of gear boxes with different number of gears and varying engine torques has proved that the above adopted method of gear selection is optimum and can be made a standard for gear selection. With this standard method of gear ratio selection the optimum gear ratio can be selected with ease and best results can be obtained.
Hybrid electric vehicle (HEV) systems offer significant improvements in vehicle fuel economy and reductions in vehicle generated greenhouse gas emissions. The widely accepted power-split HEV system configuration couples together an internal combustion engine with two electric machines (a motor and a generator) through a planetary gear set. This paper describes a methodology for analysis and optimization of alternative HEV power-split configurations defined by alternative connections between power sources and transaxle. The alternative configurations are identified by a matrix of kinematic equations for connected power sources. Based on the universal kinematic matrix, a generic method for automatically formulating dynamic models is developed. Screening and optimization of alternative configurations involves verification of a set of design requirements which reflect: vehicle continuous operation, e.g. grade test; and vehicle dynamic operation such as acceleration and drivability. Only the former are consider in this paper. The method automatically defines a design parameter space for each configuration which eventually would allow configuration evaluation and optimization, e.g. sizing of power sources or optimization of transaxle gear ratios.
Recently, due to mounting concerns regarding the environment and energy conservation, demand for compact and hybrid vehicles with good fuel economy has been increasing. Toyota Motor Corporation has developed its first hybrid transaxle for installation in sub-compact class vehicles. This new hybrid transaxle is both smaller and lighter than the P410 hybrid transaxle for compact class vehicles, including the 2009 Prius. This was accomplished by creating new designs of the gear train, motor, and motor cooling system, and by adopting advanced technology. This paper describes the major features and performance of this transaxle in detail.
Newcomers to hybrid-vehicle development are bypassing the Prius-proven powersplit system for lower cost and moderately less capable single-motor solutions. What a difference a decade, give or take a couple years, has made in the size and breadth of the hybrid-electric vehicle segment. The original duel between the Toyota Prius and Honda's Insight has grown to include, in MY2012, nearly 40 models available in the U.S. and nearly 50 worldwide. And it's hard to find an OEM that doesn't have hybrids in its product portfolio. Not long ago, for example, HEVs were about as palatable as “lite” beer to many powertrain engineers at the German OEMs, whose belief in the diesel's superiority was unwavering. But new technologies are developed as mind-sets, regulations, and strategies change. Now, vehicle electrification is a product-development priority at BMW, Volkswagen Group, and Mercedes-Benz.
AEI travels to Friedrichshafen for an exclusive look at the development and technology behind the 9HP-the industry's first nine-speed transaxle slated for MY2013 production. With its 9.84 ratio spread, clever controls, and compact packaging, ZF's new nine-speed automatic transaxle will offer OEMs capability to increase fuel economy in their front-wheel-drive vehicles by 10-16% at 75 mph (121 kph), based on the NEDC cycle, when the gearbox is launched for MY2013 production next year. Few new transmissions have caused as much buzz within the industry as the 9HP. ZF announced it at the 2011 Detroit auto show but provided almost no details of its inner workings. But this summer, ZF's top engineers gave a select group of media, including AEI, a look inside the 9HP and its development. The visit to the company's Friedrichshafen R&D center included a long test drive of three 9HP-equipped mules (see sidebar).
The Chevrolet Volt is an electric vehicle (EV) that operates exclusively on battery power as long as useful energy is available in the battery pack under normal conditions. After the battery is depleted of available energy, extended-range (ER) driving uses fuel energy in an internal combustion engine (ICE), an on-board generator, and a large electric driving motor. This extended-range electric vehicle (EREV) utilizes electric energy in an automobile more effectively than a plug-in hybrid electric vehicle (PHEV), which characteristically blends electric and engine power together during driving. A specialized EREV powertrain, called the "Voltec," drives the Volt through its entire range of speed and acceleration with battery power alone, within the limit of battery energy, thereby displacing more fuel with electricity, emitting less CO₂, and producing less cold-start emissions than a PHEV operating in real-world conditions. The Voltec powertrain architecture provides four modes of operation, including two that are unique and maximize the Volt's efficiency and performance. The specialized electric transaxle, known as the 4ET50, enables patented operating modes both to improve electric driving range when operating as a Battery Electric Vehicle (BEV) and to reduce fuel consumption when extending range by operating with the ICE. Historically, most EVs have used a single-speed electric transaxle with one motor and a fixed gear reduction. The single-speed gear reduction is a simple arrangement that takes advantage of the wide speed range of electric motors. While this arrangement can work well, the wide speed range of most electric motors comes at the price of a well-known loss of efficiency at higher motor speeds for most types of motors. Consequently, two-speed transmissions have been proposed for BEVs that can improve both tractive effort and efficiency although with the attendant additional extra gear shift hardware and controls. The Voltec 4ET50 multi-mode electric transaxle introduces a unique two-motor EV driving mode that allows both the driving motor and the generator to simultaneously provide tractive effort while reducing electric motor speeds and the total associated electric motor losses. This new operating mode, however, does not introduce the torque discontinuities associated with a two-speed EV drive. For ER operation, the Voltec transaxle uses the same hardware and controls that enable one-motor and two-motor EV operation to provide both the completely decoupled action of a pure series hybrid, as well as a more efficient powerflow with decoupled action for driving at light loads and high vehicle speed. Construction of the General Motors Company Voltec 4ET50 transaxle employs significant re-use of the General Motors Company front-wheel-drive Two-Mode Hybrid 2MT70 transaxle with modifications to enable all-speed and full-power EV operation. A new high power driving motor, optimized generator, and modified control elements allow the two EV driving modes and the two ER driving modes to be realized in the Chevrolet Volt.
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