Hybrid electric vehicles (HEVs) are worldwide recognized as one of the best and most immediate opportunities to solve the problems of fuel consumption, pollutant emissions and fossil fuels depletion, thanks to the high reliability of engines and the high efficiencies of motors. Moreover, as transport policy is becoming day by day stricter all over the world, moving people or goods efficiently and cheaply is the goal that all the main automobile manufacturers are trying to reach. In this context, the municipalities are performing their own action plans for public transport and the efforts in realizing high efficiency hybrid electric buses, could be supported by the local policies. For these reasons, the authors intend to propose an efficient control strategy for a hybrid electric bus, with a series architecture for the power-train.
Since 1978, the Agency of Industrial Science and Technology (AIST) of MITI has promoted research and development of “Large-Scale Energy Conservation Technology” popularly known as the “Moonlight Project”. As the first step, “system technology tests” using improved lead acid batteries started at Kansai Electric's Tatsumi Electric Energy Storage System Test Plant on October 1, 1986. The results showed that this system can work not only as a load-leveling apparatus but also as a high-quality power source which can support the utility power system with its load frequency control and voltage regulation capabilities. As the second step of these R&D activities, a 1MW/8MWh sodium-sulfur battery pilot plant was constructed at the same Tatsumi site. On July 11, 1991, 1000 kW× 8H facility, the largest of its type in the world, was completed and started operation. This paper describes the construction experience and operation results of the pilot plant.
The trend towards battery voltage vacuum fluorescent displays continues the technological advances in design and construction of VFD's, as they are applied to the automobile environment. With the ever increasing use of electronic displays for electronically tuned radios (ETR's), compact disc (CD) players, and other entertainment systems, advances in battery voltage displays and their associated drive circuitry have become a necessity. With the inherent advantages of low voltage operation and high information density, VFD's will continue to dominate the automobile audio markets. This paper will discuss battery voltage displays, the basic circuitry necessary to operate a vacuum fluorescent display, and comment on the “off the shelf” controller and driver circuitry available.
Inverters are solid state devices which change DC to 120VAC electricity. They are sufficiently rugged and reliable to make them practical for use on utility vehicles for operating thumpers, tools, lights and induction motor loads. The SCR type rather than the transistor type inverter is generally required for inductive and reactive loads. Static inverters operate from battery input. They provide power without running an engine, but are limited by battery capacity so work best in intermittent load applications. Dynamic inverters operate from alternator input and will handle continuous loads to 7200 watts with truck engine running.
This paper shows some aspects of the automotive voltage energy system level shift from 14 to 42 Volts. New features and prospective emissions/fuel economy requirements are creating electrical power needs in future automobiles, which today's conventional system cannot adequately supply at 14 Vdc (nominal, with a 12 Volt battery). It will be necessary to provide electric motors, DC/DC converters, inverters, battery management, and other electronic controls to meet higher voltage requirements. Suppliers must now include 42 Volt components and systems within their product range and make these new components as light, small, and cost efficient as possible. This paper is a compilation of several published works aiming to offer a synthesis to introduce this subject to the Brazilian Automotive Market.
The University of Maryland team converted a model year 2000 Chevrolet Suburban to an ethanol-fueled hybrid-electric vehicle (HEV) and tied for first place overall in the 2000 FutureTruck competition. Competition goals include a two-thirds reduction of greenhouse gas (GHG) emissions, a reduction of exhaust emissions to meet California ultra-low emissions vehicle (ULEV) Tier II standards, and an increase in fuel economy. These goals must be met without compromising the performance, amenities, safety, or ease of manufacture of the stock Suburban. The University of Maryland FutureTruck, Proteus, addresses the competition goals with a powertrain consisting of a General Motors 3.8-L V6 engine, a 75-kW (100 hp) SatCon electric motor, and a 336-V battery pack. Additionally, Proteus incorporates several emissions-reducing and energy-saving modifications; an advanced control strategy that is implemented through use of an on-board computer and an innovative hybrid-electric drive train.
THE BATTERY is the primary component limiting electric vehicle performance that equals today's standard of expectations as defined by the I. C. engine powered vehicles. Efforts to optimize the electric vehicle performance is leading many people to select and assemble the highest efficiency components available. High voltage electric vehicle power system can provide performance advantages over lower voltage systems, but only if this voltage is in balance with the total system. Mixing high efficiency components does not Insure total system efficiency optimization. The ability of a battery to release its stored energy is a function of its demand. Higher current demands will reduce the efficiency of a battery. This paper reveals how such a mismatch occurred and its reflection on what appeared to be a battery problem.
BlueStar Advanced Technology Corporation (BATC) as part of its participation in the USAF/NASA Li Ion Battery Development Consortium has developed a candidate 25-Ah cell for the Mars 2001 Lander. Although the capacity and cycle life requirements for this application are relatively modest, the low temperature performance (−20°C) and pulse discharge requirements (60A) are somewhat more challenging. Geometric requirements within the spacecraft also constrain the cell design leading to a cell with an aspect ratio quite different from those 25-Ah Li ion cells previously developed by BATC. The design of this cell and its compliance with the performance requirements of the mission will be discussed.
This paper presents a novel battery degradation model based on empirical data from the Racing Green Endurance project. Using the rainflow-counting algorithm, battery charge and discharge data from an electric vehicle has been studied in order to establish more reliable and more accurate predictions for capacity and power fade of automotive traction batteries than those currently available. It is shown that for the particular lithium-iron phosphate (LiFePO₄) batteries, capacity fade is 5.8% after 87 cycles. After 3,000 cycles it is estimated to be 32%. Both capacity and power fade strongly depend on cumulative energy throughput, maximum C-rate as well as temperature.
A very high power source solution was developed for the Non Line of Sight Launch System Container Launch Unit (NLOS-LS CLU). The power source solution has been shown to be capable of providing the required 72 continuous hours of operation and high power (3560 watts) to sustain launch capability. The power source consists of 18 BB-2590/U batteries connected in parallel in three layers. Several CLU battery systems have been delivered to the PEO and have been well accepted. The Army is using standard rechargeable batteries, is currently being upgraded with SMBus capability and higher capacity lithium-ion cells. For this reason, the CLU power source has been manufactured with SMBus capability. This paper will discuss the performance of one layer of the CLU power source to simulate the whole power load.
This paper aims at providing the scientific community with an overview of the H2020 European project 3beLiEVe and of its early achievements. The project has the objective of delivering the next generation Lithium-Nickel-Manganese-Oxide (LNMO) battery cells, in line with the target performance of the “generation 3b” Li-ion battery technology, as per EU SET-plan Action 7. Its activities are organized in three main pillars: (i) developing the 3b next generation LMNO battery cell, equipped with (ii) an array of internal and external sensors and complemented by (iii) manufacturing and recycling processes at scale. At present, 3beLiEVe is approaching the completion of its first project year (out of a total project planned duration of 42 months). Hence this paper, beyond presenting the overall project’s structure and objectives, focuses on its earliest results in the fields of the cell material formulation, arrangement of sensors and design of the battery pack.
This report addresses the technical challenges engineers must face, including the issues of storage devices, generation of the 42 volts, and distribution of power. It contains information on all of the critical aspects related to the adoption of this technology.
Mild hybridisation, using a 48 V system architecture, offers fuel consumption benefits approaching those achieved using high-voltage systems at a much lower cost. To maximise the benefits from a 48 V mild-hybrid system, it is desirable to recuperate during deceleration events at as high a power level as possible, whilst at the same time having a relatively compact and low cost system. This paper examines the particular requirements of the battery pack for such a mild-hybrid application and discusses the trade-offs between battery power capabilities and possible fuel consumption benefits. The technical challenges and solutions to design a 48 V mild-hybrid battery pack are presented with special attention to cell selection and the thermal management of the whole pack. The resulting battery has been designed to achieve a continuous-power capability of more than 10 kW and a peak-power rating of up to 20 kW.
Development of higher-voltage electrical systems in vehicles has been slowly progressing over the past few decades. However, tightening vehicle efficiency and emissions regulations and increasing demand for onboard electrical power means that higher voltages, in the form of supplemental 48 V subsystems, may soon be nearing production as the most cost-effective way to meet regulations. The displacement of high-wattage loads to more efficient 48 V networks is expected to be the next step in the development of a new generation of mild hybrid vehicles. In addition to improved fuel economy and reduced emissions, 48 V systems could potentially save costs on new electrical features and help better address the emerging needs of future drivers. Challenges to 48 V system implementation remain, leading to discussions by experts from leading car makers and suppliers on the need for an international 48 V standard. Initial steps toward a proposed standard have already been taken.
The University of Liege and Breuer Technical Development, Belgium, have designed a parallel hybrid drive train, now implemented in a VW Lupo. The original objectives of the concept were the reduction of total CO2 emissions without performance loss and an acceptable zero-emission range for inner cities. This paper presents: Metropol, a homemade hybrid simulation software, including engine cold start and dynamic battery models, hybrid management strategy for the lowest CO2 emissions, final performance, consumption and emissions of the vehicle.
The AVL International Commercial Powertrain Conference is the premier forum for truck, agricultural and construction equipment manufacturers to discuss powertrain technology challenges and solutions across their industries. The topics of the conference, which happens every two years, cover all five elements of a modern powertrain: engine, transmission, electric motor, battery and the electronic control which are used basically the same way in the quest for optimal efficiency and environmental compatibility. This event offers a unique opportunity for highly regarded professionals to address the synergy effects and distinctive characteristics of commercial vehicles, agricultural tractors and non-road vehicles, and industrial machinery. These proceedings are being co-published with SAE International, via a strategic partnership.
The 75 Ah actively cooled bipolar battery continues to undergo LEO life testing at 40% DOD and to date has completed 13,000 cycles. The EOC and EOD voltages indicate that there is slight degradation in the overall battery performance. The primary influence in this decline is considered to be one cell's poor performance. The potential for extended cycle life capability of bipolar batteries has been demonstrated. Ten 4-cell passively cooled bipolar batteries are on test at Space Systems/Loral (SS/L). Characterization testing has been completed. The results indicate that high capacity utilizations can be maintained at various discharge rates. Performance differences were noted and seem to be related to battery design variations. Further testing is planned.