Browse Topic: Electrically variable transmissions

Items (36)
Find
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 transmission is proven.
Jelaska, Damir, Perkušić, Milan, Podrug, Srdjan, Tvrdić , Vjekoslav
Design, Analysis, Simulation and Development of a Ravigneaux Gear-Train2019-26-02501/9/2019
With increased vehicular traffic density a trend has been observed where customers have started preferring automatic transmission in place of its manual version. This Automatic transmission not only shifts the gear automatically, with the help of sensors and actuators, but they are also tuned for better performance of the vehicle in terms of fuel efficiency and emission. This all comes at the cost of power consumption from the battery, increment in cost, weight and complexity. The main parts of an automatic transmission include Torque Convertor, Sensors, Actuators, Transmission Control Unit (TCU) with the epicyclic gear-train being the heart of it. In terms of use in the automotive, a system of epicyclic gear-train can provide only 2 gear ratios. Ravigneaux gear-train is the modified version of epicyclic gear-train where there are two set of Planet gears and Sun gears or Ring gears thereby capable of giving 4 gear ratios with a single system. This paper discusses the design analysis and optimization of Ravigneaux Gear-train. To compare it with Simpson gear-train, simulation of both the gear-trains are done on MATLAB(Simulink), keeping all other parameters of the vehicle like gear ratios, engine and vehicle parameters etc same and the results are compared. Acceleration for both the vehicles were same as the within 8 sec vehicle crossed the 100 kmph mark. Nature of Engine Power curve is also same for both of them. Finally, a table top model of Ravigneaux gear-train is manufactured and its performance is experimentally observed. The results are compared with percentage change in the velocity ratio and it was found that the results are within 10% of the calculated value.
Moulick, Enanko, Wani, Kiran, Kapoor, Karan, Rawat, Ankit
Offset Compound Gear Inline Two-Speed DriveTBMG-290326/1/2018
Innovators at NASA’s Glenn Research Center have developed a simple, lightweight, inline, two-speed drive that can be used either as an overall transmission, or as a supplemental add-on input transmission (i.e., overdrive or underdrive) for rotary wing aircraft and other applications benefiting from variable-speed transmission.
eFlite Dedicated Hybrid Transmission for Chrysler Pacifica2018-01-03964/3/2018
Electrified powertrains will play a growing role in meeting global fuel consumption and CO2 requirements. In support of this, FCA US has developed its first dedicated hybrid transmission (the eFlite® transmission), used in the Chrysler Pacifica Hybrid. The Chrysler Pacifica is the industry’s first electrified minivan. [2] The new eFlite hybrid transmission architecture optimizes performance, fuel economy, mass, packaging and NVH. The transmission is an electrically variable FWD transaxle with an input split configuration and incorporates two electric motors, both capable of driving in EV mode. The lubrication and cooling system makes use of two pumps, one electrically operated and one mechanically driven. The Chrysler Pacifica has a 16kWh lithium ion battery and a 3.6-liter Pentastar® engine which offers total system power of 260 hp with 84 MPGe, 33 miles of all electric range and 566 miles total driving range. [2] This paper’s focus is on the eFlite transmission.
Pittel, Mike, Martin, Dale
Lumped Parameter Based Thermo-Physical Modeling of Electrified Vehicle Transmission System2018-01-11954/3/2018
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more efficient vehicle thermal management systems to best utilize the heat produced from burning fuel and improve driveline efficiency. The greatest part of the effort is directed toward the hybridization of automotive transmission systems. The efficiency and durability of hybrid powertrain depends on the heat generation in electric motors and their interactions among each other, ambient condition, the cooling system and the transmission component configuration. These increase the complexity of motor temperature prediction as well as the computational cost of running a conjugate heat-transfer based CFD analysis. In this paper, 1D physics based thermal model is developed which allows rapid and accurate component-wise temperature estimation of the electric motor during both steady-state and transient driving cycles. The complex and combined effect of heat convection, conduction and radiation have been considered while developing the energy conservation equations. The model represents a useful tool to design and analysis of a cooling system for the electric motors of the electrified transmission systems and thus to develop more sophisticated thermal control system strategies with variable coolant flow control devices. The critical temperature predictions from the proposed were within 10% of the real-vehicle based test data under different drive cycles.
Nahid, Mohammad, Rahman, Rezwanur, Saha, Joydip, Kapatral, Shreyas, Hossainy, Tabassum Aziz, Modi, Prashant, Rahman, Sadek
Traditional and Electronic Solutions to Mitigate Electrified Vehicle Driveline Noises2017-01-17556/5/2017
Hybrid powertrain vehicles inherently create discontinuous sounds during operation. The discontinuous noise created from the electrical motors during transition states are undesirable since they can create tones that do not correlate with the dynamics of the vehicle. The audible level of these motor whines and discontinuous tones can be reduced via common noise abatement techniques or reducing the amount of regeneration braking. One electronic solution which does not affect mass or fuel economy is Masking Sound Enhancement (MSE). MSE is an algorithm that uses the infotainment system to mask the naturally occurring discontinuous hybrid drive unit and driveline tones. MSE enables a variety of benefits, such as more aggressive regenerative braking strategies which yield higher levels of fuel economy and results in a more pleasing interior vehicle powertrain sound. This paper will discuss the techniques and signals used to implement MSE in a hybrid powertrain equipped vehicle. MSE utilizes powertrain signals from the vehicle bus to determine which harmonics need to be veiled and at what output level. By enhancing and complementing the naturally occurring electric propulsion sounds, it’s possible to create a more continuous and rich hybrid powertrain sound through the hybrid transition states. As MSE is adding noise to improve the overall sound in the vehicle, this feature can also be utilized to make the vehicle sound heartier and more refined for acceleration or deceleration events while simultaneously masking unwanted tones. The MSE concepts discussed in this paper are covered under US patent 9237399.
Valeri, Frank C., Lagodzinski, James T., Reilly, Scott M., Miller, John P.
General Motors Electric Variable Transmission for Cadillac CT6 Sedan2016-01-11504/5/2016
An all-new electric variable transmission (EVT) developed by General Motors for rear-wheel-drive products is at the center of the plug-in hybrid electric vehicle (PHEV) propulsion system for the Cadillac CT6. This transmission includes two integrated electric motors, planetary gearing, and hydraulic clutches. It is capable of power-split-hybrid operation in continuously variable transmission (CVT) ratio ranges, parallel-hybrid operation in fixed gear ratios, and all-electric propulsion in different ratio combinations. Transmission operation, mechanical design, controls design, motor design, and output capability are explained, and simulation results used as the benchmark for final development are included. All-electric launch and driving, selectable regeneration, and power blending with the turbocharged engine provide smooth and seamless propulsion through the entire driving range.
Holmes, Alan, Liu, Jinming, Ames, David, Neelakantan, Vijay, Rahman, Khwaja, Grewe, Timothy
Vibration Torque Interception using Multi-Functional Electromagnetic Coupling in a HEV Drive Line2016-01-11814/5/2016
In the present paper, we introduce a drivetrain system using an electromagnetic coupling for hybrid electric vehicles, and propose a new control concept of vibration torque interception. The electromagnetic coupling is an electric machine that is composed of a pair of rotors, and electromagnetic torque acts mutually between the rotors. In the drivetrain system, the electromagnetic coupling works as a torque transmission device with a rotational-speed-converting function. We demonstrate that, by using this control, the electromagnetic coupling also works as a damping device that intercepts the vibration torque of the internal combustion engine, while transmitting the smooth torque to its drive line. Using a model of a two-inertia resonance system, a control system is designed such that a transfer function representing input-to-output torque is shaped in the frequency domain. Experimental results obtained using an electromagnetic coupling demonstrate the effectiveness of the proposed concept.
Watanabe, Takao, Fujiyoshi, Tadashi, Murakami, Akira
High Efficiency Electromagnetic Torque Converter for Hybrid Electric Vehicles2016-01-11624/5/2016
A new concept of an electromagnetic torque converter for hybrid electric vehicles is proposed. The electromagnetic torque converter, which is an electric system comprised of a set of double rotors and a stator, works as a high-efficiency transmission in the driving conditions of low gear ratio including a vehicle moving-off and as a starting device for an internal combustion engine. Moreover, it can be used for an electric vehicle driving as well as for a regenerative braking. In this concept, a high-efficiency drivetrain system for hybrid electric vehicles is constructed by replacing a fluid-type torque converter with the electromagnetic torque converter in the automatic transmission of a conventional vehicle. In this paper, we present the newly developed electromagnetic torque converter with a compact structure that enables mounting on a vehicle, and we evaluate its transmission efficiency by experiment. Furthermore, using the experimental results and finite element analysis of the electric machine, we clarify the system loss of the electromagnetic torque converter.
Watanabe, Takao, Tsuchiya, Eiji, Ebina, Masaki, Osada, Yasumitsu, Toyama, Tomoyuki, Murakami, Akira
Control Strategy of Hybrid Electric Vehicle with Double Planetary Gear Sets2015-01-12164/14/2015
Hybrid Electric Vehicles with a power split system provide a variety of possibilities to promote the fuel economy of vehicles and better adapt to various driving conditions. In this paper, a new power split system of a hybrid electric bus which consists of double planetary gear sets and a clutch is introduced. The system is able to decouple both the torque and speed of the engine from the road load, which makes it possible for the engine to operate on its optimal operation line (OOL). Considering the features of the system configuration and bus driving cycle, the driving mode of the bus is divided into Electric Vehicle (EV) mode, Electric Variable Transmission (EVT) mode and Parallel mode. By controlling the engagement of the clutch at high vehicle speed (after the mechanical point), the system operates in the parallel mode rather than EVT mode. This avoids the problem that the system efficiency sharply declines in high speed region which EVT configurations are generally faced with. Accordingly, a control strategy based on the engine OOL is proposed and a corresponding co-simulation model on the platform of Matlab/Simulink and AVL/Cruise is established. The simulation results verify that the bus is able to cover the dynamic performance requirements under UDDS cycle and reaches a fuel consumption as low as 17.84L/100km.
Song, Dafeng, Zhang, Chang, Yang, Nannan, Shang, Mingli, Peng, Yujun
Development of a Compact Compound Power-Split Hybrid Transmission Based on Altered Ravigneaux Gear Set2014-01-17934/1/2014
Several types of power-split hybrid transmissions are outlined and the strengths and weaknesses of typical compound power-split prototype designs are summarized in this paper. Based on an modified Ravigneaux gear set, a novel compound power-split hybrid transmission with compact mechanical structure is presented, its dynamic and kinematic characteristics in equations and operating modes are described, and then equivalent lever diagrams are used to investigate the proposed compound power-split device. Control strategies in different operating modes are discussed with the simplified combined lever diagram, and a global optimization method is implemented to find the optimum operation point for the hybrid powertrain. To evaluate the fuel economy of a hybrid car equipped with this hybrid transmission, a forward powertrain simulation model is developed and real vehicle performance tests are conducted in the chassis dynamometer. Simulations and test results show that the proposed hybrid transmission can improve the efficiency of the powertrain and demonstrate lower fuel consumptions than the corresponding conventional vehicle. We conclude that the most effective strategy for reducing the cost of vehicle powertrain manufacturing, decreasing the difficulty of control and improving vehicle fuel efficiency during city driving is to employ the new compound power-split hybrid transmission.
Wang, Chen, Zhao, Zhiguo, Zhang, Tong, Dai, Xianjun, Yuan, Xiyue
Optimal Design Strategies for Different Hybrid Powertrain Configurations Assessed with European Drive Cycles2013-01-17514/8/2013
The quality of the powertrain design has a significant impact on the fuel consumption and emissions of hybrid vehicles. Lack of experience with these relatively new technologies, the enormous variety of hybrid powertrain configurations, and the multitude of components make this area an ideal application for computer-based modeling and optimizations. Global optimization techniques have the advantage to explore systematically the design space to find the optimal configuration space. In this paper, a systematic procedure for an optimal design of hybrid powertrain configurations using an evolutionary algorithm is proposed. It will be shown that the design steps for parallel and power-split configurations are quite similar. This results in a computing approach with high synergy effects and the ability to exchange components seamless to compare different ‘virtual’ configurations.
Boehme, Thomas Juergen, Becker, Bernd, Ruben-Weck, Michael, Rothschuh, Matthias, Boldt, Alexander, Rollinger, Christoph, Butz, Robert, Rabba, Heiko, Drewelow, Wolfgang
Modeling and Development of E85 Fueled Two-Mode Hybrid Electric Vehicle2013-01-05474/8/2013
Texas Tech University (TTU) was one of sixteen universities competing in EcoCAR:-The Next Challenge competition. It is a three year collegiate advanced vehicle technology competition where teams are challenged to re-engineer a General Motors(GM) donated vehicle to achieve improved fuel economy and reduced emissions while maintaining consumer acceptability in the areas of stock performance, utility and safety. Two-mode hybrid which is an electrically variable transmission was selected as the Texas Tech team's architecture. The first year of the competition emphasized vehicle design through Powertrain System Analysis Toolkit (PSAT) software. The vehicle design parameters were established through vehicle technical specifications(VTS), development of software-in-the-loop (SIL) and hardware in-the-loop (HIL) techniques, rapid control system prototyping and components selection and sizing. These first year activities were continued for the vehicle development and refinement in subsequent years of the competition. This paper describes the design procedure of SIL, HIL and rapid prototyping. The Mathworks Simulink, SimDriveline, SimScape and Stateflow software provided an environment for modeling selected architecture and powertrain components. Once the model was verified HIL testing was performed with the use of National Instruments PXI and dSpace MicroAutoBox (MABX). In this way the process moved from mathematical models to lab based tests with HIL. A realistic vehicle propulsion controller was developed by moving to in-vehicle testing of the vehicles' on board software.
Patil, Kunal, Bayne, Stephen, Maxwell, Timothy T.
Control and Testing of a 2-Mode Front-Wheel-Drive Hybrid-Electric Vehicle2012-01-11924/16/2012
The new General Motors 2-mode hybrid transmission for front-wheel-drive vehicles has been incorporated into a 2009 Saturn Vue by the West Virginia University EcoCAR team. The 2-mode hybrid transmission can operate in either one of two electrically variable transmission modes or four fixed gear modes although only the electrically variable modes were explored in this paper. Other major power train components include a GM 1.3L SDE turbo diesel engine fueled with B20 biodiesel and an A123 Systems 12.9 kWh lithium-ion battery system. Two additional vehicle controllers were integrated for tailpipe emission control, CAN message integration, and power train hybridization control. Control laws for producing maximum fuel efficiency were implemented and include such features as engine auto-stop, regenerative braking and optimized engine operation. The engine operating range is confined to a high efficiency area that improves the overall combined engine and electric motor efficiency. Simulation results using Powertrain System Analysis Toolkit (PSAT) indicate fuel economy of 28.4/29.4 mpgge over the customized Morgantown Urban Drive Schedule (MUDS)/Route 19 Highway (R19HW), 14.6 second 0-60 mph and 8.6 second 50-70 mph acceleration time. The on-road test results indicated fuel economy of 24.5/31.5 mpgge over the MUDS/R19HW cycles, 16 seconds 0-60 mph and 10 seconds 50-70 mph acceleration time.
Zhu, Zhenhua, Ward, Douglas, Wayne, W. Scott
A Simulation-Based Comparison of Different Power Split Configurations with Respect to the System Efficiency2012-01-04384/16/2012
In power-split configuration, the input power is split into two parts, one of which is transmitted from the internal combustion engine through one or more planetary gear(s) to the wheels. The other part is generated as electricity and passes through an electrical variator to assist the driving torque. The latter has the characteristic of poor efficiency. In this simulation study, a comparison among the input power-split, compound power-split, and two mode power-split are discussed. Output power-split is not mentioned in this paper due to its limited applicability in specific vehicles. The idea of selection of the electrical machines is explained: the speed and torque of electrical machines was taken into consideration for the required transmission ratios spread.
Boehme, Thomas, Metwally, Osama, Becker, Bernd, Meinhardt, Nikolaj, Rucht, Martin, Rabba, Heiko, Drewelow, Wolfgang
Methodology for Assessment of Alternative Hybrid Electric Vehicle Powertrain System Architectures2012-01-10104/16/2012
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.
Zaremba, Alexander T., Soto, Ciro, Jennings, Mark
Power-Split HEV Control Strategy Development with Refined Engine Transients2012-01-06294/16/2012
Power-split hybrid-electric vehicles (HEVs) employ two power paths between the internal combustion (IC) engine and the driven wheels routed through gearing and electric machines (EMs) composing an electrically variable transmission (EVT). The EVT allows IC engine control such that rotational speed can be independent of vehicle speed at all times. By breaking the rigid mechanical connection between the IC engine and the driven wheels, the EVT allows the IC engine to operate in the most efficient region of its characteristic brake specific fuel consumption (BSFC) map. If the most efficient IC engine operating point produces more power than is requested by the driver, the excess IC engine power can be stored in the energy storage system (ESS) and used later. Conversely, if the most efficient IC engine operating point does not meet the power request of the driver, the ESS delivers the difference to the wheels through the EMs. Therefore with an intelligent supervisory control strategy, power-split architectures can advantageously combine traditional series and parallel power paths. Previous work compared two different power-split HEV powertrains using a 2-term cost function and steady-state backward-looking simulation (BLS). BLS was used to find battery power management strategies resulting in minimized fuel consumption over a user-defined drive-cycle. The supervisory control strategy design approach amounts to an exhaustive search over all kinematically admissible engine and EM operating points, leading to a minimized instantaneous cost function. While the approach provides a valuable comparison of two architectures, non-ideal engine speed fluctuations result, preventing the control strategy from being effectively implemented. In the present work, two approaches are investigated for refining IC engine state transitions for use in an implemented control strategy: i) smoothing the 2-term cost function optimization results, and ii) introducing a 3-term cost function. These approaches are tested and verified in high-fidelity forward-looking simulations (FLSs). It is found that both refinement approaches effectively reduce engine speed transitions, and result in fuel economy (FE) estimates and component operation which compare well to BLS results. It is further found that the 3-term cost function finds more efficient operating points than the smoothed 2-term cost function approach. From the investigations carried out in this paper, a two-phase control strategy development process is suggested where control strategies are first explored using highly-efficient steady-state BLS models, and then further tested and refined in high-fidelity FLS models. Favorable comparison of BLS and FLS results justify the efficacy of the two-phased process, suggesting rapid and effective development of implementable power-split HEV supervisory control strategies.
Arata, John, Leamy, Michael, Cunefare, Kenneth
Power Modules and Inverter Evaluation for GM Electrification Architectures2012-01-03404/16/2012
GM has recently developed two kinds of vehicle electrification architectures. First is VOLTec, a heavy electrification architecture, and second is eAssist, a light electrification architecture. An overview, of IGBT power modules & inverters used in VOLTec and eAssist, is presented. Alternative power modules from few cooperative suppliers are also described in a benchmarking study using key metrics. Inverter test set up, procedure and instrumentation used in GM Power Electronics Development Lab, Milford are described. GM electrification journey depends on Power Electronics lab' passive test benches; double pulse tester, inductive resistive load bench and active emulator test cell without electric machines. Such test benches are preferred before dyne test cells are used for inverter software/hardware integration and motor durability tests cycles. Specific test results are presented. Power modules reliability tests; power cycle, intermittent operation life and thermal air shock, as specified by GM and performed by Tier 1/2 suppliers are also described.
Desai, Prakash H., Bartolucci, Sean, Fatema, Marzia, Weiss, Ronald
Configuration Design, Development and Experimental Validation of Two New Powertrains for Parallel Hybrid Electric Vehicle2012-28-00241/9/2012
Hybridization of a light duty diesel vehicle based on two new different power train concepts for a parallel hybrid vehicle is discussed. The paper focuses on the design, development and performance evaluation of two new parallel HEV power trains. The diesel electric hybrid vehicles are different from other hybrids with regard to the power train. Two new hybrid drive-trains namely, a post-transmission architecture using an additional simple PGT, and a coupled PGT based parallel hybrid transmission are designed. To demonstrate the practical applicability, two research prototypes equipped with these power trains are built with the same degree of hybridization. The implementation of the new designs enables to overcome many problems encountered in the traditional vehicles. Among the various control strategies, a rule based control strategy is considered for the hybrid vehicles. The prototypes of hybrid electric vehicle are tested on chassis dynamometer and test tracks. Drive cycle used for testing of the vehicle is also discussed. Test results are analyzed and compared to an emulated diesel vehicle. The performance parameters include fuel consumption, mass emission, maximum speed and vehicle acceleration. Possible modes of operation in the intended configurations are also stated. Even if one system (the electrical system or the IC engine) fails, still the vehicle would remain functional on the other system. Based on this study, hybrid powertrain strategies for future vehicles are proposed.
Gupta, A. K., Ramanarayanan, C. P., Amarnath, C., Seth, B.
Kinematic Study of the GM Front-Wheel Drive Two-Mode Transmission and the Toyota Hybrid System THS-II Transmission2011-01-08764/12/2011
General Motors has recently developed a front-wheel drive version of its two planetary two-mode transmission (2-MT) for a hybrid-electric vehicle powertrain [1]. This newer transmission includes two planetary gears with two transfer clutches and two braking clutches. With activation of designated pairs of these four clutches, four fixed-gear ratios between the transmission's input shaft and output shaft are obtained. In addition, activation of specific individual clutches gives two modes of operation whereby the IC engine speed is decoupled from the vehicle velocity thus providing an electrical continuously variable transmission (ECVT). This present paper extends the power-split analysis in [2] by deriving a safe-operating region (SOR) in the plane of IC engine speed vs. vehicle velocity for the four fixed-gear and two ECVT modes. This SOR is bounded by the speed limitations of the 2-MT components. Similar results are presented for the Toyota Hybrid System II (THS-II) transmission. Also developed is the vehicle velocity limit for both the 2-MT and the THS-II transmissions under battery electric vehicle (BEV) operation.
Meisel, Jerome
Backward-Looking Simulation of the Toyota Prius and General Motors Two-Mode Power-Split HEV Powertrains2011-01-09484/12/2011
This paper presents a comparative analysis of two different power-split hybrid-electric vehicle (HEV) powertrains using backward-looking simulations. Compared are the front-wheel drive (FWD) Toyota Hybrid System II (THS-II) and the FWD General Motors Allison Hybrid System II (GM AHS-II). The Toyota system employs a one-mode electrically variable transmission (EVT), while the GM system employs a two-mode EVT. Both powertrains are modeled with the same assumed mid-size sedan chassis parameters. Each design employs their native internal combustion (IC) engine because the transmission's characteristic ratios are designed for the respective brake specific fuel consumption (BSFC) maps. Due to the similarities (e.g., power, torque, displacement, and thermal efficiency) between the two IC engines, their fuel consumption and performance differences are neglected in this comparison. The road-load parameters defining each system are used to calculate the required mechanical power at the driven wheels necessary to follow a given drive-cycle. Admissible engine operating states are sought based on component performance limitations and the required mechanical power at the driven wheels. Each IC engine operating point defines an accompanying battery power consistent with the constraints of the electric machines. The design approach is to exhaustively search all admissible states and minimize an instantaneous cost function based on engine power and battery power, at each time instant of the drive-cycle. Two cost functions are considered which weight battery power usage using either a linear, or an inverse-tangent, function of the current battery state-of-charge (SOC). Selected operational states are then compared against each other based on the flexibility and power delivery capabilities of the powertrains. Fuel minimizing cost functions are determined with the assistance of a charge sustaining index introduced by this paper. Finally, the most fuel efficient choices are used to determine the expected efficiency of both powertrains considered.
Arata, John, Leamy, Michael J., Meisel, Jerome, Cunefare, Kenneth, Taylor, David
Modeling and Drivability Assessment of a Single-Motor Strong Hybrid at Engine Start2010-01-14405/5/2010
Using a clutch to disconnect and shut-off the engine when engine power is not required, the single-motor strong hybrid has the potential for significant fuel economy improvement with reduced costs and less system complexity. However, it is a challenge for the single-motor strong hybrid to maintain acceptable drivability at engine start since it requires diverting motor torque through a slipping clutch to start the engine. In this study, dynamic simulations of the hybrid transmission driveline with hydraulic and motor controls have been employed to assess the feasibility of the single-motor strong hybrid, to address drivability issues specific to this hybrid architecture at engine start, and to develop control methods to manage driveline disturbances to an acceptable level.
He, Yongsheng, Bucknor, Norman K., Smith, Anthony L., Yang, Hong
Defining the Hybrid Drive System for the WVU ClearVue Crossover Sport Utility Vehicle2010-01-08414/12/2010
West Virginia University (WVU) is a participant in EcoCAR - The NeXt Challenge, an Advanced Vehicle Technology Competition sponsored by the U.S. Department of Energy, and General Motors Corporation. During the first year of the competition, the goal of the WVU EcoEvolution Team was to design a novel hybrid-electric powertrain for a 2009 Saturn Vue to increase pump-to-wheels fuel economy, reduce criteria tailpipe emissions and well-to-wheels greenhouse gas emissions (GHG) while maintaining or improving performance and utility. To this end, WVU designed a 2-Mode split-parallel diesel-electric hybrid system. Key elements of the hybrid powertrain include a General Motors 1.3L SDE Turbo Diesel engine, a General Motors Corporation 2-Mode electrically variable transmission (EVT) and an A123 Systems Lithium-Ion battery system. The engine will be fueled on a blend of 20% soy-derived biodiesel and 80% petroleum-derived ultra-low sulfur diesel fuel (B20). Emissions control is accomplished by a diesel oxidation catalyst, a catalyzed diesel particulate filter and selective catalytic reduction (SCR) with urea injection. Simulation results using the Powertrain System Analysis Toolkit (PSAT) developed by Argonne National Laboratory (ANL) indicate a combined cycle fuel economy of 6.2-liter/100 km, (32 mpg) gasoline equivalent, ≤150 g/km well-to-wheels (WTW) greenhouse gas emissions and ≤0.4 kWh/km petroleum energy use while maintaining an 8.0 second 0-60 acceleration time and 680 kg (1500 lb) towing capacity. Passenger capacity, cargo capacity and utility are not sacrificed by addition of the electrical energy storage and hybrid propulsion systems.
Zhu, Zhenhua, Yablonski, Andrew, Mearns, Howard, Wayne, William
Instantaneously Optimized Controller for a Multimode Hybrid Electric Vehicle2010-01-08164/12/2010
A multimode transmission combines several power-split modes and possibly several fixed gear modes, thanks to complex arrangements of planetary gearsets, clutches and electric motors. Coupled to a battery, it can be used in a highly flexible hybrid configuration, which is especially practical for larger cars. The Chevrolet Tahoe Hybrid is the first light-duty vehicle featuring such a system. This paper introduces the use of a high-level vehicle controller based on instantaneous optimization to select the most appropriate mode for minimizing fuel consumption under a broad range of vehicle operating conditions. The control uses partial optimization: the engine ON/OFF and the battery power demand regulating the battery state-of-charge are decided by a rule-based logic; the transmission mode as well as the operating points are chosen by an instantaneous optimization module that aims at minimizing the fuel consumption at each time step. The controller is then implemented in a Simulink/Stateflow controller that can be used in Argonne's PSAT (Powertrain System Analysis Toolkit), a forward-looking powertrain simulation toolkit with dynamic plant models. As a result, the controller described in this paper is realistically implementable on an actual vehicle. Simulation results show the mode use and describe the practical operations of the system.
Karbowski, Dominik, Kwon, Jason, Kim, Namdoo, Rousseau, Aymeric
Bond Graph Modeling and Analysis of Series-Parallel Hybrid Electric Vehicle Transmissions2010-01-13094/12/2010
The bond graph method is used to model kinematics of various one-mode and two-mode series-parallel configurations of hybrid electric vehicle transmissions. Based on the derived speed and torque equations, a comparative analysis of hybrid transmissions steady-state behaviors is conducted. An example of control-oriented bond graph modeling of hybrid transmission dynamics is presented, as well.
Cipek, Mihael, Deur, Josko, Petric, Josko
Truck Utility & Functionality in the GM 2-Mode Hybrid2010-01-08264/12/2010
The present production General Motors 2-Mode Hybrid system for full-size SUVs and pickup trucks integrates truck utility functions with a full hybrid system. The 2-mode hybrid system incorporates two electro-mechanical power-split operating modes with four fixed-gear ratios. The combination provides fuel savings from electric assist, regenerative braking and low-speed electric vehicle operation. The combination of two power-split modes reduces the amount of mechanical power that is converted to electric power for continuously variable transmission operation, meeting the utility required for SUVs and trucks. This paper describes how fuel economy functionality was blended with full-size truck utility functions. Truck functions described include: Manual Range Select, Cruise Control, 4WD-Low and continuous high load operation.
Tamai, Goro, Reeves, Shannon, Grewe, Timothy H.
General Motors Front Wheel Drive Two-Mode Hybrid Transmission2009-01-05084/20/2009
General Motors has developed a two-mode hybrid transmission for transverse front wheel drive vehicles. Mechanical components for this system were packaged into the basic space constraints of a conventional automatic transmission by using a space-saving arrangement of two planetary gear sets and four clutches extending through two electric motors with large internal diameters. This full-function hybrid system delivers electric propulsion for low-speed urban driving, regenerative braking, electric acceleration assist, two continuously variable engine-to-wheels speed ranges, and four fixed gear ratios. This electrically-variable transmission is based on a scalable architecture for applications ranging from small vehicles and engines to full-size vehicles with large engines and towing capacity.
Hendrickson, James, Holmes, Alan, Freiman, David
Developing Mode Shift Strategies for a Two-Mode Hybrid Powertrain with Fixed Gears2008-01-03074/14/2008
Two-mode hybrid architectures with three planetary gear sets and four clutches will bring both flexibility and complexity to energy management of powertrains. In order to take full advantage of the increased degrees of freedom, highly delicate operation strategies are needed. We develop transmission efficiency models for power-split modes, and present a mode shift strategy assuming no battery power. When battery load leveling is additionally considered, the respective optimal operation set for each mode can be obtained and compared to yield a mode shift algorithm for general hybrid operation situations. The investigation of the strategies shows how frequently each mode is used, and verifies the effectiveness of fixed gear operations. We check the validity of the strategies by applying the algorithm to dynamic optimization and by predicting how it works during an actual driving simulation.
Ahn, Kukhyun, Cha, Suk Won
Defining the General Motors 2-Mode Hybrid Transmission2007-01-02734/16/2007
The new General Motors 2-Mode Hybrid transmission for full-size, full-utility SUVs integrates two electro-mechanical power-split operating modes with four fixed gear ratios and provides fuel savings from electric assist, regenerative braking and low-speed electric vehicle operation. A combination of two power-split modes reduces the amount of mechanical power that must be converted to electricity for continuously variable transmission operation. Four fixed gear ratios further improve power transmission capacity and efficiency for especially demanding maneuvers such as full acceleration, hill climbing, and towing. This paper explains the basics of electro-mechanical power-split transmissions, input-split and compound-split modes, and the addition of fixed gear ratios to these modes to create the 2-Mode Hybrid transmission for SUVs.
Grewe, Tim M., Conlon, Brendan M., Holmes, Alan G.
The Algebraic Design of Transmissions & EVTs2007-01-14584/16/2007
This paper describes the creation of novel transmission mechanisms using algebraic design techniques. The objective is to create novel arrangements comprised of one or more planetary gear sets, a pair of motor-generators and several torque-transmitting mechanisms (clutches and brakes). The algebraic design procedure represents the planetary gear sets, fixed interconnections, clutches/brakes, and motor-generator sets as algebraic constraints. Appropriate subsets of constraint equations are solved to identify viable transmission mechanism designs. We have used the above design approach to create several novel candidate multi-speed transmissions as well as EVT concepts. The main benefit of the algebraic design procedure is that it allows the designer to systematically generate and assess novel designs.
Raghavan, Madhusudan, Bucknor, Norman, Maguire, Joel, Hendrickson, James, Singh, Tejinder
Advancing the State of Strong Hybrid Technology2006-21-005810/16/2006
As the hybrid automotive market becomes quickly saturated with highly competitive products and vehicles, auto manufacturers struggle with business models and the combination of current manufacturing with next generation development. The hybrid development cooperation amongst General Motors, DaimlerChrysler, and BMW offers a new business model that promotes the advancement of the state of strong hybrid technology while maintaining the strong global leadership and competition.
Schell, Andreas
Island Concept EVT2006-01-326010/16/2006
This paper presents an all-wheel-drive (AWD) hybrid electric vehicle (HEV) design approach for extreme off-road applications. The paper focuses on the powertrain design, modeling, simulation, and performance analysis. Since this project focuses on a military-type application, the powertrain is designed to enhance crew survivability and provide several different modes of limp-home operation by utilizing a new vehicle topology -herein referred to as the island topology. This topology consists of designing the vehicle such that the powertrain and other equipment and subsystems surround the crew compartment to provide a high level of protection against munitions and other harmful ordnance. Thus, in the event of an external shield penetration, the crew compartment remains protected by the surrounding equipment - which serves as a secondary shield. The powertrain system principally consists of two internal combustion engines which are coupled to three electric machines using two planetary gear sets, and also includes other transmission elements. A detailed design of the powertrain is presented, which considers the vehicle layout, space claim issues, and extreme operating conditions. Next in the paper, the mathematical model of the powertrain is outlined. The powertrain model is quasi-static, meaning that it neglects high-frequency dynamics due, for example, to gear elasticity. The model however, takes into account the inertias of the various components, as well as accounting for the parasitic losses due to friction. Finally, the powertrain model is implemented in a simulator program that provides an all-encompassing tool that allows for a complete analysis of the energy flow within the powertrain components. With this, the powertrain control strategy can be formulated with the objective of minimizing fuel consumption and / or maximizing performance using a trade-off approach.
Cantemir, Codrin-Gruie, Ursescu, Gabriel, Serrao, Lorenzo, Rizzoni, Giorgio, Bechtel, James, Udvare, Thomas, Letherwood, Michael
An Analytic Foundation for the Toyota Prius THS-II Powertrain with a Comparison to a Strong Parallel Hybrid-Electric Powertrain2006-01-06664/3/2006
Hybrid-electric powertrains for passenger vehicles and light trucks are generally being designed with two different configurations described as follows: The Toyota Hybrid System, THS-II, implemented in the 2004 Prius, the Lexus 400-H, and the Ford Hybrid Escape, is a power-split approach involving two electric machines and an internal combustion engine (ICE) mechanically coupled by a three-shaft planetary gear train. The second leading approach is a parallel hybrid-electric powertrain that generally includes a single electric machine and an ICE with a mating multi-ratio transmission. These parallel configurations are further divided as weak parallel and strong parallel. Honda uses a weak parallel powertrain in their Insight and Hybrid Civic. At Georgia Tech a strong (full), split-parallel hybrid powertrain has been implemented in a Ford Explorer. The vehicle is referred to as the Model GT. After presenting an analytic description of the THS-II operation, this paper then compares and contrasts the THS-II and Model GT powertrains outlining the advantages and disadvantages of each design.
Meisel, Jerome
Comparative Analysis of Single and Combined Hybrid Electrically Variable Transmission Operating Modes2005-01-11624/11/2005
Electrically variable transmissions divide power between the electrical and mechanical paths using input, output, or compound split schemes. When combined with an electrical energy storage element such as a battery, these systems allow numerous fuel saving and performance benefits. This paper examines the design tradeoffs in each of the three topologies in order to balance fuel economy, system performance against requirements, and electrical component size. A general EVT analysis method is presented and used to study the fuel economy and performance sensitivity of the three configurations to motor, inverter, and battery constraints, and planetary gear ratios. To evaluate fuel economy, the three systems are assessed for each of the primary fuel economy mechanisms enabled by hybridization. To evaluate performance tradeoffs, system performance against typical vehicle performance design points is compared. The effects of combining two modes that are optimized for individual speed ranges vs. a single mode covering all ranges are also discussed. The use of 2 modes provides significant advantages over a single mode design including reduced motor power for a given vehicle performance.
Conlon, Brendan
A Dual-Use Hybrid Electric Command and Control Vehicle2001-01-277511/12/2001
Until recently, U.S. government efforts to dramatically reduce emissions, greenhouse gases and vehicle fuel consumption have primarily focused on passenger car applications. Similar aggressive reductions need to be extended to heavy vehicles such as delivery trucks, buses, and motorhomes. However, the wide range of torques, speeds, and powers that such vehicles must operate under makes it difficult for any current powertrain system to provide the desired improvements in emissions and fuel economy. Hybrid electric powertrains provide the most promising, near-term technology that can satisfy these requirements. This paper highlights the configuration and benefits of a hybrid electric powertrain capable of operating in either a parallel or series mode. It describes the hybrid electric components in the system, including the electric motors, power electronics and batteries. In addition, the paper illustrates the installation of this hybrid electric hardware into a 17,000 kg (GVW) military vehicle based on an RV chassis. The analyses of the new system show that conventional benchmarks for performance and fuel economy can be met or exceeded. In fact, fuel economy increased 50 percent on an urban cycle and 25 percent on average for five different cycles. Finally, the benefits of this powertrain for military initiatives such as the 21st Century Army and 21st Century Truck Initiative will be discussed, including how the Dual-Use Hybrid Electric Command and Control Vehicle can provide a source for up to 150 kW of auxiliary electrical power.
Kluger, Michael A., Szkubiel, Don, Bass, Edward A.
Porsche Carrera 2 Tiptronic Transmission9017609/1/1990
As an alternative for the manual five-speed transmission of the Porsche 911 Carrera 2, a modern automatic transmission featuring a manual shift option and a driving style dependent control system was to be developed, which matches this sportscar's particular character. Based on the targets set for this concept, the following paper explains the design and performance characteristics of the Porsche Tiptronic which is the first of a new generation of transmissions.
Petersmann, Josef, Seidel, Willi, Möllers, Werner
Items per page:
1 – 36 of 36