Criteria

Text:
Sector:
Display:

Results

Viewing 1 to 30 of 2930
2010-10-25
Journal Article
2010-01-2204
Yue Ma, Ho Teng, Marina Thelliez
Lithium-ion (Li-ion) batteries are becoming widely used high-energy sources and a replacement of the Nickel Metal Hydride batteries in electric vehicles (EV), hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV). Because of their light weight and high energy density, Li-ion cells can significantly reduce the weight and volume of the battery packs for EVs, HEVs and PHEVs. Some materials in the Li-ion cells have low thermal stabilities and they may become thermally unstable when their working temperature becomes higher than the upper limit of allowed operating temperature range. Thus, the cell working temperature has a significant impact on the life of Li-ion batteries. A proper control of the cell working temperature is crucial to the safety of the battery system and improving the battery life. This paper outlines an approach for the thermal analysis of Li-ion battery cells and modules.
2011-04-12
Technical Paper
2011-01-0345
Suresh Gopalakrishnan, Chandra Namuduri, Michael Reynolds
In this paper, a low-cost means to improve fuel economy in conventional vehicles by employing ultracapacitor based Active Energy Recovery Buffer (AERB) scheme will be presented. The kinetic energy of the vehicle during the coast down events is utilized to charge the ultracapacitor either directly or through a dc-dc converter, allowing the voltage to increase up to the maximum permissible level. When the vehicle starts after a Stop event, the energy stored in the capacitor is discharged to power the accessory loads until the capacitor voltage falls below a minimum threshold. The use of stored capacitor energy to power the accessory loads relieves the generator torque load on the engine resulting in reduced fuel consumption. Two different topologies are considered for implementing the AERB system. The first topology, which is a simple add-on to the conventional vehicle electrical system, comprises of the ultracapacitor bank and the dc-dc converter connected across the dc bus.
2011-04-12
Technical Paper
2011-01-0671
Kristel Coronado, John Lyons, Randy Curtis, Thomas Wang
Hybrid high voltage battery pack is not only heavy mass but also large in dimension. It interacts with the vehicle through the battery tray. Thus the battery tray is a critical element of the battery pack that interfaces between the battery and the vehicle, including the performances of safety/crash, NVH (modal), and durability. The tray is the largest and strongest structure in the battery pack holding the battery sections and other components including the battery disconnect unit (BDU) and other units that are not negligible in mass. This paper describes the mass optimization work done on one of the hybrid batteries using CAE simulation. This was a multidisciplinary optimization project, in which modal performance and fatigue damage were accessed through CAE analysis at both the battery pack level, and at the vehicle level.
2011-04-12
Technical Paper
2011-01-0666
Sowmyalatha Jayaraman, Gordon Anderson, Shailendra Kaushik, Philip Klaus
Fuel economy and stringent emissions requirements have steered the automotive industry to invest in advanced propulsion hybrids, including Plug-in hybrid vehicles (PHEV) and Fuel cell vehicles. The choice of battery technology, its power and thermal management and the overall vehicle energy optimization during different conditions are crucial design considerations for PHEVs and battery electric vehicles (BEV). Current industry focus is on Li-Ion batteries due to their high energy density. However, extreme operating temperatures may impact battery life and performance. Different cooling strategies have been proposed for efficient thermal management of battery systems. This paper discusses the modeling and analysis strategy for a thermally managed Lithium Ion (Li-Ion) battery pack, with coolant as the conditioning medium.
2011-04-12
Technical Paper
2011-01-0668
Yue Ma, Ho Teng
Lithium ion batteries can be developed for vehicle applications from high power specification to high energy specification. Thermal response of a battery cell is the main factor to be considered for battery selection in the design of an electrified vehicle because some materials in the cells have low thermal stability and they may become thermally unstable when their working temperature becomes higher than the upper limit of allowed operating range. In this paper the thermal characteristics of different sizes and forms of commercially available batteries is investigated through electro-thermal analysis. The relation between cell capacity and cell internal resistance is also studied. The authors find that certain criteria can be defined for battery selection for electric vehicles, hybrid electric vehicles and plug-in hybrid electric vehicles. These criteria can be served as design guidelines for battery development for vehicle applications.
2011-04-12
Technical Paper
2011-01-0667
Ramesh Rebba, Jeong Hun Seo, Ann Marie Sastry, Mary Fortier
Rechargeable energy storage systems with Lithium-ion pouch cells are subject to various ambient temperature conditions and go through thousands of charge-discharge cycles during the life time of operation. The cells may change their thickness with internal heat generation, cycling and any other mechanisms. The stacked prismatic cells thus experience face pressure and this could impact the pack electrical performance. The pack consists of stiff end plates keeping the pack in tact using bolts, cooling fins to maintain cell temperature and foam padding in between cells. The pack level thermal requirements limit the amount of temperature increase during normal operating conditions. Similarly, the structural requirements state that the stresses and the deflection in the end plates should be minimal. Uncertainties in cell, foam mechanical and thermal properties might add variation to the pack performance.
2011-04-12
Journal Article
2011-01-0654
Taeyoung Han, Seongyong Park, Uiseong Kim, Chee burm Shin
As battery temperature greatly affects performance, safety, and life of Li-ion batteries in plug-in and electric vehicles under various driving conditions, automakers and battery suppliers are paying increased attention to thermal management for Li-ion batteries in order to reduce the high temperature excursions that could decrease the life and reduce safety of Li-Ion batteries. Currently, the lack of fundamental understanding of the heat generation mechanism due to complex electrochemical phenomena prohibits accurate estimation of the heat generation within Li-ion cells under various operating conditions. Heat from Li-ion batteries can be generated from resistive dissipation, the entropy of the cell reaction, heat of mixing, and other side chemical reactions. Each of these can be a significant source of heat under a range of circumstances.
2011-04-12
Technical Paper
2011-01-0669
Azadeh Sheidaei, Xinran (Sharon) Xiao, Xiaosong Huang, Jixin Wang
The mechanical behavior of a commercially available single layer polypropylene (PP) separator was investigated using a dynamic mechanical analyzer (DMA). Samples were tested along the machine direction (MD) and transverse direction (TD). The tensile stress-strain, tensile creep and viscoelastic behaviors were studied. Experiments were performed in two conditions: (1) dry and (2) wet, i.e., samples submersed in dimethyl carbonate (DMC). The experimental results revealed that the mechanical properties of the separator were much lower while being submersed in DMC. This finding suggests that the mechanical properties measured at a dry condition may not be sufficient to represent the in-situ material behavior. Therefore, it is important to conduct material characterization in an environment close to the service condition.
2011-04-12
Technical Paper
2011-01-0653
Vijayakanthan Damodaran, Siva Murugan, Vinod Shigarkanthi, Sunil Nagtilak, Karthikeyan Sampath
This paper deals with the development of a generic approach for the thermal management of batteries used in electric vehicles. A lumped parameter model was used to determine the worst case scenario of the battery operation from thermal management standpoint. Certain driving conditions were identified as the worst load cases of battery thermal management and these driving conditions were then used to conduct on-road tests. Using the results obtained from the vehicle performance simulation and on-road tests CFD simulations were carried out to establish a relationship between the air flow requirements and the heat generated from the battery. These relations help to obtain a quick estimate of the air flow requirement to keep the battery within safe temperature limits. This methodology developed is valid for all types of batteries used in electric vehicles such as Lead Acid, Lithium Ion, Ni-MH etc.
2010-10-10
Technical Paper
2010-01-1682
Michael Herbert Putz
Scientists at the Austrian Institute of Technology (AIT), formerly Austrian Research Center, focused on investigating electro mechanical brakes (EMB) for automobiles. Research showed that EMBs can address brake distribution with regenerative and friction braking ("blending") at hybrid and electric cars due to the ability of the EMBs to be actuated as required (and do not automatically produce brake force at pedal activation). The target was to develop an EMB with low actuation force and energy that is simple and reliable, rolls back to disengage when power is off and acts as a parking brake. Several solutions were considered (with and without self-amplification). A pivotal mechanism with very high transmission ratio using eccentricity emerged as a favorable solution. Vienna Engineering (VE) took over and assumed the research during 2010. VE revealed that non-linear behavior facilitated low actuation forces at high braking torque and can use a controlled amount of self-amplification.
2010-10-10
Technical Paper
2010-01-1683
Alberto Boretti
Improvements of fuel economy of passenger cars and light- and heavy-duty trucks are being considered using a flywheel energy storage system concept to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking and then assisting torque requirements. The mechanical system has an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids rated at about 36%. The technology may improve the vehicle fuel economy and hence reduced CO₂ emissions by more than 30% over driving cycles characterized by frequent engine start/stop, and vehicle acceleration, brief cruising, deceleration and stop.
2011-04-12
Technical Paper
2011-01-0124
Dominic John, Pundlik Ghodke PhD, Nilesh Gajarlawar, Jidhin Joseph lng
High speed diesel engines are difficult to start in cold conditions (at subzero temperature) because the cylinder head and cylinder block absorbs heat of compression and thus preventing ignition due to the high surface to volume ratio. Also the coolant and the engine oil become viscous at subzero temperature and make the condition unfavorable for starting. Combustion optimization along with the help of a heating aid can make these engines to start quickly without any engine misbehavior. Cold startability is the ability of an engine to start within a specified time and continue to run without any malfunctioning. Combustion instability will lead to the misfiring of the engine unless it is calibrated properly. The European countries are subjected to a minimum temperature of -20°C to -25°C. So the intention of this work is to optimize the cold startability of Mahindra's Multi-Purpose Vehicle (MPV) up to -25°C which is to be sold in European countries.
2011-04-12
Journal Article
2011-01-0125
David Lejsek, Andre Kulzer
The introduction of CO₂-reduction technologies like Start-Stop or the Hybrid-Powertrain and the future emission legislation require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the ECU makes an explicit thermodynamic analysis of the combustion process during the start-up necessary. Initially, the well-known thermodynamic analysis of in-cylinder pressure at stationary condition was transmitted to the highly non-stationary engine start-up. There, the current models for calculation of the transient wall heat fluxes were found to be misleading. Therefore, adaptations to the start-up conditions of the known models by Woschni, Hohenberg and Bargende were introduced for calculation of the wall heat transfer coefficient in SI engines with gasoline direct injection. This paper shows how the indicated values can be measured during the engine start-up.
2011-04-12
Technical Paper
2011-01-0060
Srinivasa Raju Gavarraju
Engine starting torque requirement at extreme cold and hot conditions is not possible to evaluate by transient dynamometer. Due to this, starting system design may not meet the engine starting requirements under all operating environments. Starter motor can be used to overcome this problem. This paper deals with how to evaluate engine starting torque at all temperatures through starter motor. Conventionally, engine cold startability and hot startability are evaluated by using a starter motor of bigger rating. A new methodology found to circumvent this issue and it is, by evaluating the strain experienced by the pinion and drive mechanism, engine starting torque demand can be evaluated at any temperature. By this process, starting system design can be made to suit the correct requirements of the engine starting.
2010-04-12
Journal Article
2010-01-1236
Neeraj S. Shidore, Anant Vyas, Jason Kwon
This paper evaluates the impact of energy management strategy on the cost benefits of a plug-in hybrid electric vehicle (PHEV) by taking into account the impact of PHEV energy management on battery life and petroleum displacement over the life of the vehicle. Using Battery in the Loop (BIL), a real battery is subjected to transient power demands by a virtual vehicle. The vehicle energy management strategy is varied, resulting in different battery utilization scenarios. Battery life, which varies with battery utilization, is estimated for the different energy management scenarios. The same representative drive cycle is used over the different energy management strategies to isolate the impact of energy management on battery utilization. PHEV gasoline savings, in comparison to a charge sustaining hybrid, are calculated for each of the energy management strategies, for a fixed distance of 40 miles.
2013-05-13
Technical Paper
2013-01-2006
Sung-Kwon Hong, Bogdan Epureanu, Matthew Castanier
The goal of this work is to develop an efficient numerical modeling method for the vibration of hybrid electric vehicle (HEV) battery packs to support probabilistic forced response simulations and fatigue life predictions. There are two important sources of variations in HEV battery packs that affect their structural dynamic response. One source is the uncertain level of pre-stress due to bolts or welds used for joining cells within a pack. The other source is small structural variations among the cells of a battery pack. The structural dynamics of HEV battery packs are known to feature very high modal density in many frequency bands. That is because packs are composed of nominally identical cells. The high modal density combined with small, random structural variations among the cells can lead to drastic variations in the dynamic response compared with those of the ideal nominal system.
2013-04-08
Technical Paper
2013-01-1226
Prabhavathy Rajappan, Jaishankar Cinnasamy, Ulaganathan Shanmuganathan, Dominic S M
This paper presents a case study of design, development and testing of Ultra Capacitor (UC) based energy storage system for effective voltage ride-through in Armored Fighting Vehicle (AFV) applications. It also presents the test results of UC module delivering full load of AFV. AFV is powered with 24 V, 400 Ah battery bank and 28 V, 20 kW generator located in hull. Source is connected to the load through common single wire DC bus and chassis is the return path. DC bus voltage drops down to 16 V, during starting of heavy load. As the entire mission related sensitive systems are also connected to same DC bus, voltage sag in DC bus creates undesirable effects. Due to advancement in the field of double layer capacitor, UC module based ride-through system is developed and tested. Total capacitance of 23 F, 35.1 V UC modules was developed using 13 cells of Faradigm UCs. Dynamic voltage equalization circuit is connected across all the cells to protect the cells against over voltage.
2013-04-08
Technical Paper
2013-01-1229
Ajinkya Chinchwadkar, Alok Khare
Currently, OEMs worldwide are emphasizing more upon development and implementation of new electrical features on existing vehicles [3]. However, development and implementation of new electrical features on existing vehicle platforms create architectural as well as packaging challenges. These challenges are augmented due to following: the need to implement such features across different body styles of vehicles that are based on same or different architectures different requirement for a feature based upon market requirement This paper analyzes these challenges to help in providing design solutions for successful implementation of new features as per following requirements: 1 Provide optimum design to have low cost and high quality for existing vehicle platforms2 Provide spare capacity while designing new vehicles or architectures
2013-04-08
Journal Article
2013-01-0474
Masanori Monde, Masataka Kosaka
For safe and fast refueling hydrogen to fuel cell vehicles (FCVs) at hydrogen refueling stations (HRSs), a refueling protocol is under discussion at SAE J2601 to be a global standard. In order to realize such a standard, we have to estimate the relation between gas temperature and pressure during a refueling and for an accurate estimation we have to correctly understand the thermal characteristics of hydrogen tank. Fast refueling test data has been offered by BMW-Powertech, some test cases have been analyzed by a simulation model developed by Monde et al. It reveals that the hydrogen temperature at the end of refueling does not exceed 85°C for these analyzed cases. The effect of the pressure drop between storage bank and hydrogen tank was negligible on the gas temperature at the end of refueling, although the gas temperature shows different profile depending on the pressure drop.
2004-03-08
Technical Paper
2004-01-0119
Fuyuan Yang, Jingyong Zhang, Qiang Han, Minggao Ouyang
The high emission level during start-up process of common rail diesel engine is still a problem for ultra low emission control. For the map-based common rail system, engine start-up process goes through the initialization of injection and rail pressure build-up process, so the fuel injection status is not stable. Based on the analysis of the characteristics of rail pressure build-up, engine speed variety and exhausted smoke emission during engine start-up process, it is found that the injection parameters of the initial phase of engine start-up have large effects on the start-up time and smoke emission. To optimize the smoke emission, this paper makes a study on the methods of determining the injection parameters during start-up by means of well-phased investigation of engine speed and orthogonal bench test. The research is carried out on a 6-cylinder 7.8L turbocharged diesel engine equipped with a DENSO ECD-U2 common-rail system.
2004-03-08
Technical Paper
2004-01-0569
Peter J. Wezenbeek, David G. Evans, David P. Sczomak, John P. Absmeier, Gerald T. Fattic
Implementation of engine turnoff at idle is desirable to gain improvements in vehicle fuel economy. There are a number of alternatives for implementation of the restarting function, including the existing cranking motor, a 12V or 36V belt-starter, a crankshaft integrated-starter-generator (ISG), and other, more complex hybrid powertrain architectures. Of these options, the 12V belt-alternator-starter (BAS) offers strong potential for fast, quiet starting at a lower system cost and complexity than higher-power 36V alternatives. Two challenges are 1) the need to accelerate a large engine to idle speed quickly, and 2) dynamic torque control during the start for smoothness. In the absence of a higher power electrical machine to accomplish these tasks, combustion-assisted starting has been studied as a potential method of aiding a 12V accessory drive belt-alternator-starter in the starting process on larger engines.
2004-03-08
Technical Paper
2004-01-0566
James E. Walters, Ronald J. Krefta, Gabriel Gallegos-Lopez, Gerald T. Fattic
Due to the need for improving fuel economy, reducing tailpipe emissions and the trend towards increasing electrical content in automobiles, hybrid drivetrains are being considered by the automotive industry. In the foreseeable future, in order to address the drive towards hybridization, vehicle manufacturers will begin to use a 42 volt-based architecture in conjunction with an integrated starter and generator system. Depending on the desired power level and allowable changes to the vehicle drivetrain, either an Integrated Starter Generator which mounts between the engine and the transmission or a Belt Alternator Starter (BAS) system which mounts on the accessory belt can be used. This paper will examine the impact of choosing either a Permanent Magnet (PM) machine or an Induction machine for a BAS application. The impact of the technology on the electric machine design process, power stage implementation, control strategy and overall system design philosophy will be discussed.
2004-03-08
Technical Paper
2004-01-0544
Ulrich Kramer, Klaus Badke, Frank Wytrykus, Dieter Wissussek
Spark ignited engines with direct fuel injection into the combustion chamber can be started by injecting fuel into the combustion chamber of the stopped engine and igniting it afterwards with the spark plug. The explosion of the air fuel mixture initially rotates the crankshaft. The engine is started without motoring the crankshaft with a starter device. The described start procedure is called “Direct Start”. For a successful Direct Start a maximum oxygen concentration in the “Direct Start Cylinders” (the cylinders utilized initially for the Direct Start) is required, because the oxygen concentration in the start cylinders determines the maximum amount of energy, which can be exploited to move the crankshaft over the following “TDC” (Top Dead Center). After the engine stop the Direct Start Cylinder valves are closed. Therefore the oxygen concentration has to be maximized during the preceding engine shut down.
2004-03-08
Technical Paper
2004-01-0365
S. P. Gladyshev, Terry Feldpausch, N. Natarajan, I. S. Okrainskaya
The electrical power consumption in automobiles continues to increase thereby demanding higher power capability of the alternator. The standard alternator today is a claw-pole synchronous machine. The claw-pole alternators have brushes which are maintenance issue; it is not possible to increase power output by increasing the stack length; and the rotor inertia is large due to the steel core and rotor excitation coil. Despite these disadvantages, the claw-pole alternator is still used because of its low cost and ease of manufacturing. An alternator with DC stator excitation, has a laminated salient pole rotor with no excitation coil. Therefore the weight and inertia is less than in the claw-pole alternator. The excitation coil is located in the stator and therefore there are no brushes needed. In this type of alternator, the stator has three-phase output coils evenly shifted in space 120 degrees.
2004-03-08
Technical Paper
2004-01-0383
Christophe Ramstein, Henry da Costa, Danny Grant
Haptics refers to the sense of touch. The challenge of designing and integrating high-quality programmable haptic interfaces requires technical knowledge, usability experience and software tools. This paper provides design guidelines for software tools intended to facilitate the design and integration of programmable haptic controls and describes a suite of fundamental tools to which the design guidelines have been applied. Immersion Studio® for Automotive (ISA) is a user-friendly software application for interactively designing and programming haptic sensations. ISA supports a large variety of devices including 1D and 2D force feedback devices. Together with the Immersion API for Automotive and firmware, ISA constitutes the basis for creating high-quality programmable haptic systems.
2004-03-08
Technical Paper
2004-01-0368
Sun Liqing, Chen Wei, Yu Leiyan, Yang Lianghui, Li Yufang, Sun Fengchun
The paper presents the design and analysis of pure electric bus powered by Lithium-ion battery and ultra capacitor. For the limited power energy of battery, the ultra capacitor pack is chosen as the auxiliary on-board energy storage device. The system configuration, system modeling and on-road test result analysis will be covered in the paper and the possibility of using ultra capacitors on electric bus to improve the economical efficiency in urban areas will be discussed.
2004-03-08
Technical Paper
2004-01-1504
Tomohiro Waku, Norihiko Watanabe, Joji Matsumoto, Junichi Nakanishi
A windshield defroster has an important roll of clearing up fogged window glasses of a vehicle by blowing out warm air. In simulations parameters that affect the defogging time are the velocity, humidity and temperature of the flow from a defroster nozzle. However, individually varying all the parameters and investigating their effects will lead to many computing cases and long runtime. An approach that can considerably reduce calculation time is proposed. The approach is dictated by two key-steps: 1) First, steady-state velocity distributions for several different defroster flow rates are calculated; 2) Secondly, based on the pre-calculated velocity fields, the defogging time is estimated. This approach is compared to the conventional method that always couples all the parameters in transient calculations.
2004-03-08
Technical Paper
2004-01-1569
Jürgen Engbring, Matthias Ebert, Stefan Werry
For several years flat cables for the use in the automotive wiring harnesses have been attracting attention. Less weight, less space and higher automation degree are the key factors, which promise a benefit from the introduction of the new technology. The well defined electromagnetic properties are also often mentioned as an advantage of flat cables, because of the precise and constant routing in the car. Although it is true, that statistical error due to an unfavorable position of the cables in the harness is reduced, on the other hand the systematical error due to it's geometry is strongly enhanced. Since basic parameters like impedance or crosstalk characteristics are not specified for the cable types for CAN-transmission used in automotive, it is difficult to qualify a selected wiring system in the early development phase of a car model.
2004-03-08
Technical Paper
2004-01-1572
Kelvin Shih
A low cost fault tolerant and redundant multiplex wiring system specifically designed for automotive applications is described in this paper. Although there are many multiplex wiring systems are being used to simplify the car wiring harness, but very few are low cost, fault tolerant and redundant at the same time. Most of the system address mainly the protocol and software issues and neglected the reliability of the multiplex wiring system. This paper addresses the fault tolerant and redundancy of the system and use hardware based integrated circuit to convert from parallel to serial at the transmitter side and serial to parallel at the receiver side.
2004-03-08
Technical Paper
2004-01-1565
Jerome K. Hastings, Joseph C. Zuercher, Engelbert Hetzmannseder
Experimental data and analysis show the relationship between arcing watts, the time of the arc exposure and the degree to which common polymers experience damage. Arcing test apparatus for 125V DC and 48 volt DC are shown. Arc gap control allows 125-volts to mimic arcs in lower voltage systems. Arcing current waveforms depict the chaotic behavior of arcs and differences due to anode / cathode materials. Levels of degradation are defined and used for “Constant Damage Contours” for Vinyl, Carpeting and Sound insulation. The polymers were exposed to conditions of constant arcing watts for increasing times. Connecting the points of “first flame” establishes a “contour of constant damage”. The data indicates that a “3 second flame free” limit is between 50 and 100 watts. 4000 watts of arcing takes 1/4 to ½ second to cause burning. The influence of circuit resistance on the maximum arc power transfer is presented.
Viewing 1 to 30 of 2930

Filter

  • Range:
    to:
  • Year: