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A major decision to make in design projects is the selection of the best technology to provide some needed system functionality. In making this decision, the designer must consider the range of technologies available and the performance of each. During the useful life of the product, the technologies composing the product evolve as research and development efforts continue. The performance evolution rate of one technology may be such that even though it is not initially a preferably technology, it becomes a superior technology after a few years. Quantifying the evolution of these technologies complicates the technology selection decision. The selection of energy storage technology in the design of an electric car is one example of a difficult decision involving evolving technologies.

Military and civilian vehicles are moving towards more electrification, in response to the increasing demand for multi-mode missions, fuel consumption and emissions reduction, and dual use electrical and electronic components. Consequently, the vehicle electric load is increasing rapidly. For military vehicles, these electrical loads include: the loads for electric traction (EV and HEV), cabin climate conditioning, vehicle control and actuation, actuation by wire (X by wire), sensors, reconnaissance, communications, weapons etc. All these requirements need to be supported by an efficient, fast responding and high capacity energy storage system. The electric load of a vehicle can be decomposed into two components--- static and dynamic loads. The static component is slowly varying power with limited magnitude, whereas the dynamic load is fast varying power with large magnitude. The energy storage system, accordingly, comprises of two basic elements.

A concept of “driving situation awareness”-driven energy management system for parallel hybrid electric vehicles (HEVs) is introduced. The essential feature of the proposed energy management system is to assess the driving environment (in terms of facility type combined with traffic congestion level) using long and short term statistical features of the drive cycle. Subsequently, this knowledge is provided to a system that makes intelligent decisions with respect to the torque distribution and charge sustenance tasks. Simulation work was carried out for the validation of proposed system, and the results reveal its viability for energy management of parallel hybrid vehicles.

Due to their harsh operating environments, military vehicle drive trains have special requirements. These special requirements are usually represented by hill climbing ability, obstacle negotiation, battlefield cross country travel, hard acceleration, high speed, etc. These special requirements need the vehicle drive train to have a wider torque and speed range characteristics than commercial vehicles. We have proved that larger constant power ratio in electric motor can significantly enhance the vehicle acceleration performance. In other words, for the same acceleration performance, large constant power ratio can minimize the power rating of the traction motor drive, thus minimizing the power rating of the power source (batteries for instance). Actually, extension of the constant power range can also significantly enhance the gradeability, which is crucial for military vehicles.

A fuzzy logic technique is presented in this paper for sensorless speed and position identification of vector-controlled PWM inverterfed PMSM drives used in EV/HEV propulsion systems. Fuzzy logic is used to estimate the rotor speed and position. Operation of the drive is studied by numerical simulation. The performance for different drive conditions is also analyzed and the results are shown in the paper. Simulation results show that the proposed control method can be effectively used in controlling the PMSM drives with high performance for EV/HEV applications. It is found that the fuzzy logic system is reliable without using any speed or position sensor.

The need of upfront modeling, simulation and design optimization has been ever increasing during full vehicle product development process. The overall vehicle system and component subsystem performances remain critical considerations for making final product release decision. With these challenges in mind, the work of this paper discusses the development of feasible CAE methods, tools, and processes for multi-objective design optimization. A full integrated tractor trailer truck vehicle is used as an example to demonstrate this capability. The proposed approach allows several design objectives to be simultaneously optimized, which might otherwise be extremely difficult to achieve with experimental methods.

Conventional spark plugs ignite a fuel-air mixture via an electric-to-plasma energy transfer; the effectiveness of which can be described by an electric-to-plasma energy efficiency. Although conventional spark plug electric-to-plasma efficiencies have historically been viewed as adequate, it might be wondered how an increase in such an efficiency might translate (if at all) to improvements in the flame initiation period and eventual engine performance of a spark-ignition engine. A modification can be made to the spark plug that places a peaking capacitor in the path of the electrical current; upon coil energizing, the stored energy in the peaking capacitor substantially increases the energy delivered by the spark. A previous study has observed an improvement in the electric-to-plasma energy efficiency to around 50%, whereas the same study observed conventional spark plug electric-to-plasma energy efficiency to remain around 1%.

Two parallel HEV control concepts: ‘thermostat’ and ‘power split’ are compared in this paper. To achieve a substantial improvement in fuel economy, the ‘thermostat’ or ‘on/off’ control technique intended to improve the fuel efficiency of a series HEV has been adopted and designed for parallel HEV. Among different ‘power split’ concepts developed for parallel hybrids only the ‘electrically assist’ algorithm is considered in this paper. These two control concepts are compared for three parallel HEV architectures: pre-transmission, post-transmission and continuous variable transmission hybrids. The comparison study also includes the effect of hybridization factor-the ratio of the electric power to the total propulsion power. The matrices of comparison are level of performance, energy consumption and exhaust emissions. The SAE J1711 partial charge test procedure is followed.

There is a clear trend towards Hybrid Electric Vehicles (HEV) due to the environmental concerns. On the other hand, with increasing hotel and ancillary loads and replacement of more engine driven mechanical and hydraulic loads with electrical loads, automotive systems are becoming more electric. This is the concept of More Electric Cars (MEC) which necessitates going to a higher voltage such as 42V for conventional cars. Can the evaluation of the 42V MEC smoothly lead to the Hybrid Electric Vehicles (HEV) and More Electric Hybrid Vehicles (MEHV)? In this paper, we investigate the feasibility of 42V & 14+42V electrical power systems for MEHV. Technical issues of such a solution are explored in detail.

Vehicle dynamics requires extended-speed, constant-power operation from the propulsion system in order to meet the vehicle's operating constraints (e.g., initial acceleration and gradeability) with minimum power. Decrease in power rating will decrease the volume of the energy storage system. However, extending the constant power operating range of the electric drives increases its rated torque, thereby, increasing motor volume and weight. This paper investigates the effect of extended constant power operation on battery driven electric vehicle (BEV) propulsion system taking the change in motor weight and battery volume into account. Five BEV systems with five traction drive having different base speeds are simulated for this study. The performances of the BEVs are obtained using FUDS and HWYFET drive cycles. Two EV-HEV software packages ‘V-ELPH’ developed by Texas A&M University and ‘ADVISOR’ from NREL are used for simulation testing.

Short circuit incidents on traction motors can cause ‘wheel-locking’ on the vehicle, and may have an adverse impact on vehicle stability. This paper investigates the necessity of fault-tolerant motors for EV and HEV traction applications. Reaction of resulting fault torques differ along with electric motor types and fault variety. The paper analyzes the short-circuit behavior of three basic motor types: permanent magnet, induction and switched reluctance motor. The analysis is based on the transient simulation of the three most common inverter short-circuit cases and their effect on vehicle stability.

The recent growing interest in electric vehicle (EV) and hybrid electric vehicle (HEV) demands for an efficient, reliable and economical motor drive for electric propulsion. However, searching for a suitable traction motor becomes quite involved when vehicle dynamics and system architecture are considered. This paper makes an in-depth investigation on two highly important traction motor characteristics, extended speed range-ability and energy efficiency, from vehicular system perspective. The influences of these two motor drive features on a pure EV, a post-transmission, and two pre-transmission parallel HEV with 20% and 50% hybridization are studied in this paper. Two EV-HEV software packages ‘V-ELPH’ developed by Texas A&M University and ‘ADVISOR’ from NREL are used for simulation purposes. Based on the results in this paper, a systematic method is developed regarding the selection of traction drives for EV and HEV propulsion systems.

An electromechanical gear is presented along with design examples utilizing the electromechanical gear in hybrid electric vehicle drive trains. The designs feature the electromechanical gear (the Transmotor) in place of traditional mechanical transmissions and/or gearing mechanisms. The transmotor is an electric motor suspended by its shafts, in which both the stator and the rotor are allowed to rotate freely. The motor thus can provide positive or negative rotational energy to its shafts by either consuming or generating electrical energy. A design example is included in which the transmotor is installed on the output shaft of an internal combustion engine. In this arrangement the transmotor can either increase or decrease shaft speed by applying or generating electrical power, allowing the ICE to operate with a constant speed.

This paper addresses the fundamental issues faced in the aircraft electrical system architectures. Furthermore, a brief description of the conventional and advanced aircraft power system architectures, their disadvantages, opportunities for improvement, future electric loads, role of power electronics, and present trends in aircraft power system research will be given. Finally, this paper concludes with a brief outline of the projected advancements in the future.

Rotordynamics developed from the beginning of the 20th century to deal with problems associated with steam turbines. This paper deals with intense developments starting around 1975 through 2000 in rotordynamics to deal with new, larger machines running at higher speeds and higher power levels. Most of the new problems of interest dealt with subsynchronous instabilities. Issues associated with “synchromnously unstable” motion due to the Morton Effect is also reviewed.

A vehicle's performance depends greatly on the operating conditions, such as journey type, driving behavior etc. Driving patterns vary with geographical location and traffic conditions. In today's global economy where automobile industries are concerned with both local and international markets, it becomes necessary to investigate vehicle performance for driving cycles of different countries and develop vehicle designs which are appropriate to the consumer's market. This paper concentrates on the issues related to designing hybrid electric vehicles. A method of optimizing the size of the principal hardware components of hybrid vehicles such as, electric motors, internal combustion engines, transmissions and energy storage devices based on the demands of different drive cycles is discussed in the paper.