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Despite—or because of—California’s vaunted love affair with the automobile, the state could become a leader in the development of new, climate change–friendly transport. Electric cars, hybrid vehicles, plug-in electric hybrids, robotic cars, vehicles powered by natural gas or other fuels, car sharing, bike sharing, and the matching of unused vehicle space with potential passengers are just some of the ideas on the near horizon in the Golden State. [ABSTRACT FROM PUBLISHER]

The braking system of hybrid electric vehicle (HEV) is composed of friction and regenerative braking system, meaning that braking torque is generated by the collaboration of the friction and regenerative braking system. With the attributes, there are two problems in the HEV braking system. First, rapid deceleration occurs due to dynamic characteristic difference when shifting the friction and regenerative braking systems. Second, the friction braking torque alters with temperature because the friction coefficient changes with the temperature. These problems cause the vehicle to be unstable. In this paper, the concurrence control and compensation control were proposed to solve these problems. And also, the concurrence control and compensation control were combined for the stability of the braking system. In order to confirm the effect of these control algorithms, the experiment and simulation were conducted. Consequently, it was confirmed that the control algorithm of this study improved the vehicle safety and stability. [ABSTRACT FROM AUTHOR]

Virtual power plant (VPP) is the owner and/or manager of a group of distributed generations as well as some end consumers, which may have random behavior. In addition to the uncertainties associated with generation and demand, the market price is also a source of uncertainty in VPP scheduling. In this paper, a novel stochastic operating strategy is proposed for VPPs to participate in day-ahead market, considering different uncertainties in generation, consumption, and electricity market price. Highly stochastic consumption of plug-in hybrid electric vehicles (PHEVs) is also considered in the present study, as an emerging source of uncertainty. To mitigate the loading effect of PHEVs on the network, a smart charging strategy is proposed, which encourages the owners to charge their PHEVs in off-peak hours, and the results of this strategy are used in estimating the load. To achieve the maximum profit for the VPP in an electricity market, different methods based on point estimation method and Monte Carlo simulation are analyzed to handle the uncertainties. Moreover, three strategies are proposed for charging PHEVs, and their effect on VPP's total cost is compared. The proposed stochastic programming is solved by a modified version of teaching-learning-based optimization algorithm. Numerical simulations on modified 18-bus distribution system corroborate the efficacy of the proposed methodology. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Increased use of electric vehicles has been proposed as a means of reducing anthropogenic carbon dioxide emissions. It is therefore reasonable to compare emissions associated with generating the electricity used by electric vehicles with the emissions associated with internal-combustion vehicles, including hybrid-electric vehicles. The student exercises in this activity will permit students to understand the trade-offs involved in making a choice of vehicles. When emissions from electrical generation are taken into account, electric vehicles that obtain power in most U.S. states do have lower emissions than gasoline-powered vehicles, but in some states the heavy use of fossil fuels for electric generation causes electric vehicles to do no better than gasoline-powered hybrid vehicles. In a few states, electric vehicle emissions are worse than those from comparable hybrid vehicles. [ABSTRACT FROM AUTHOR]

This paper proposes a novel multiple-input bidirectional dc–dc power converter to interface more than two dc sources of different voltage levels. This finds applications in hybrid electric/fuel cell vehicles (FCVs), where different dc sources of unequal voltage levels need to be connected with bidirectional power flow capability. The converter can be used to operate in both the buck and boost modes with bidirectional power control. It is also possible to independently control power flow between any two sources when more than two sources are actively transferring power in either directions. The operation, analysis, and design of the converter are presented with different modes of power transfer. The proposed converter is demonstrated for FCV application using real-time hardware-in-the-loop system. Experimental results for a 5-kW system are presented, validating the theoretical analysis. [ABSTRACT FROM PUBLISHER]

In this paper, we analyze the limitations that impose the presence of uncertainty in the design of optimal energy management strategies (EMSs) for fuel cell (FC) hybrid electric vehicles. Using an electric powertrain constituted by a hydrogen FC and a battery bank, the fuel consumption minimization problem is analyzed in the presence of parametric uncertainty. The conditions that ensure that the nominal optimization problem matches the solution of the real (unknown) optimization problem are clearly stated. By observing that the uncertainty will limit the feasible solutions of the minimization consumption problem, supervisory control constituted by heuristic rules is proposed to face such limitations, resulting in a mixed optimal–heuristic EMS. The effect of the powertrain design, driving cycle, and initial conditions in the proposed strategy is discussed. Numerical simulations provide evidence of the advantages and features of the supervisory control strategy. [ABSTRACT FROM PUBLISHER]

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X-rings were introduced as a result of the limitations of O-rings that twist, especially during dynamic applications. The X-ring design avoids twisting, and the presence of a groove between the lobes acts as a lubricant reservoir that improves the packing life of these seals. Because of the multiple seal points, less squeeze rate is required to provide an effective seal. In addition, friction and wear is decreased, which increases seal life and decreases maintenance costs. Therefore, a better understanding of the behavior and stress distribution of X-rings under a loading condition of uniform squeeze rate and internal pressure is necessary. However, most research to date has been done on the O-ring. We focused on analysis of contact length and contact stresses developed in X-rings under a uniform squeeze rate of 20% (which is suitable for static applications) using a photoelastic experimental hybrid method, and ascertained the packing ability of the X-ring. We show that sealing rings with the X geometry have considerably higher contact stresses than O-ring seals. Also, the contact stresses were higher than the internal stresses of the X-ring. Therefore, our analysis of the contact stresses is adequate in establishing the behavior of the X-ring. [ABSTRACT FROM AUTHOR]

A MPC5554-based hybrid control unit (HCU) is developed for a series-parallel hybrid electric bus ( SPHEB) in this paper. Firstly considering the operation features and powertrain configuration of SPHEB with minimizing fuel consumption as objective, a real-time optimal energy management strategy (EMS) based on iterative dynamic programming global optimization algorithm and Elman dynamic neural network is proposed. Then according to the vehicle requirements and EMS, the hardware system of HCU is designed with MPC5554 as CPU. Finally HCU hardware-in-the-loop simulation test is conducted with ETAS PT-LABCAR as platform. The results demonstrate that the developed HCU operates stable and reliable and can effectively realize real-time control for the SPHEB, significantly improving the fuel economy of the vehicle. [ABSTRACT FROM AUTHOR]

An empirical research on the prospects and key factors of electric vehicle development is conducted based on the questionnaires survey in the EVS25 symposium. The results demonstrate that both battery electric vehicles and hybrid electric vehicles have good prospects, in which the latter have more mature application condition. Some technical and economic factors such as price and supporting facilities are key issues for EV development, that are quite different between China and other countries. Different commercial modes and battery charging modes own different acceptances but all have certain demands, so it is not appropriate to simply accept one and reject another. [ABSTRACT FROM AUTHOR]

Plug-in hybrid electric vehicles (PHEVs) have the potential of substantially reducing petroleum consumption and vehicular CO2 emissions relative to conventional vehicles. The analysis presented in this article first ascertains the cost-effectiveness of PHEVs from the perspective of the consumer. Then, the potential effects of PHEVs to an electric utility are evaluated by analyzing a simplified hypothetical example. When evaluating the cost-effectiveness of a PHEV, the additional required premium is an important financial parameter to the consumer. An acceptable amount for the additional upfront costs will depend on the future costs of gasoline and the on-board battery pack. The need to replace the on-board battery pack during the assumed vehicle lifetime also affects the allowed premium. A simplified unit commitment and dispatch model was used to determine the costs of energy and the CO2 emissions associated with PHEVs for different charging scenarios. The results show that electricity can be used to charge PHEVs during off-peak hours without an increase in peak demand. In addition, the combined CO2 emissions from the vehicles and the electric generation facilities will be reduced, regardless of the charging strategy. [ABSTRACT FROM AUTHOR]

An assessment is made of on-the-road performance, for a pure hydrogen fuel cell car, a pure battery operated car, and a hydrogen fuel cell-battery hybrid car. The tool used for this study is the modular software-package ADVISOR [Markel T, et al. ADVISOR. J Power Sources 2002; 110:255–66], which is well tested and offers a range of simple, parametrized sub-models or more detailed physical models for the fuel cell stack, the batteries, the electric motor, the exhaust control, the transmission and entire power train including controls and control strategies. The basis configuration of the cars modelled is characterized by high energy efficiency, before adding a fuel cell and electric motor also of high conversion efficiencies. Preceding the presentation of results, the best way to characterize energy efficiency is discussed. [Copyright &y& Elsevier]