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Hybrid Electric Vehicles (hybrid + electric_vehicle)
Selected AbstractsFuzzy torque distribution control for a parallel hybrid vehicleEXPERT SYSTEMS, Issue 1 2002Jong-Seob Won A fuzzy torque distribution controller for energy management (and emission control) of a parallel hybrid electric vehicle is proposed. The proposed controller is implemented in terms of a hierarchical architecture which incorporates the mode of operation of the vehicle as well as empirical knowledge of energy flow in each mode. Moreover, the rule set for each mode of operation of the vehicle is designed in view of an overall energy management strategy that ranges from maximal emphasis on battery charge sustenance to complete reliance on the electrical power source. The proposed control system is evaluated via computational simulations under the FTP75 urban drive cycle. Simulation results reveal that the proposed fuzzy torque distribution strategy is effective over the entire operating range of the vehicle in terms of performance, fuel economy and emissions. [source] Shortest path stochastic control for hybrid electric vehiclesINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2008Edward Dean Tate Jr Abstract When a hybrid electric vehicle (HEV) is certified for emissions and fuel economy, its power management system must be charge sustaining over the drive cycle, meaning that the battery state of charge (SOC) must be at least as high at the end of the test as it was at the beginning of the test. During the test cycle, the power management system is free to vary the battery SOC so as to minimize a weighted combination of fuel consumption and exhaust emissions. This paper argues that shortest path stochastic dynamic programming (SP-SDP) offers a more natural formulation of the optimal control problem associated with the design of the power management system because it allows deviations of battery SOC from a desired setpoint to be penalized only at key off. This method is illustrated on a parallel hybrid electric truck model that had previously been analyzed using infinite-horizon stochastic dynamic programming with discounted future cost. Both formulations of the optimization problem yield a time-invariant causal state-feedback controller that can be directly implemented on the vehicle. The advantages of the shortest path formulation include that a single tuning parameter is needed to trade off fuel economy and emissions versus battery SOC deviation, as compared with two parameters in the discounted, infinite-horizon case, and for the same level of complexity as a discounted future-cost controller, the shortest-path controller demonstrates better fuel and emission minimization while also achieving better SOC control when the vehicle is turned off. Linear programming is used to solve both stochastic dynamic programs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Integrated control method for a fuel cell hybrid systemASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009Hongwen He Abstract To apply a fuel cell engine (FCE) on a hybrid electric vehicle, an integrated control method is put forward according to the driving characteristics of the vehicle. The FCE's output power is self-regulated to minimize hydrogen consumption and at the same time to meet the driving power requirement of the vehicle. For the difference of the power output dynamics, the actual power difference between the FCE and the vehicle load is compensated passively by a secondary power battery pack. Vehicle experiments show that the fuel cell hybrid system works well without any adverse influence on the vehicle power performance. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Aliovalent Substitutions in Olivine Lithium Iron Phosphate and Impact on Structure and PropertiesADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Nonglak Meethong Abstract Lithium transition metal phosphate olivines are enabling a new generation of high power, thermally stable, long-life rechargeable lithium batteries that may prove instrumental in the worldwide effort to develop cleaner and more sustainable energy. Nanoscale (<100,nm) derivatives of the olivine family LiMPO4 (M,=,Fe, Mn, Co, Ni) are being adopted in applications ranging in size scale from hybrid and plug-in hybrid electric vehicles to utilities-scale power regulation. Following the previous paradigm set with intercalation oxides, most studies have focused on the pure ordered compounds and isovalent substitutions. In contrast, even the possibility for, and role of, aliovalent doping has been widely debated. Here, critical tests of plausible defect compensation mechanisms using compositions designed to accommodate Mg2+, Al3+, Zr4+, Nb5+ ions on the M1,and/or M2 sites of LiFePO4 with appropriate charge-compensating defects are carried out, and conclusive crystallographic evidence for lattice doping, e.g., up to at least 12 atomic percent added Zr, is obtained. Structural and electrochemical analyses show that doping can reduce the lithium miscibility gap, increase phase transformation kinetics during cycling, and expand Li diffusion channels in the structure. Aliovalent modifications may be effective for introducing controlled atomic disorder into the ordered olivine structure to improve battery performance. [source] Natural gas internal combustion engine hybrid passenger vehicleINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2008S. Wright Abstract The implementation of hybrid electric vehicles powered with alternative fuels is critical in reducing national dependence on imported crude oil, addressing the detrimental environmental impact of increasing petroleum usage worldwide, and sustaining the national economy. The question is not whether changes should be made, but instead centers on identifying pathways that will lead to the greatest environmental and economic benefits. To avoid misuse of limited infrastructure investment, the objective of this research is to consider a broad range of relevant factors to determine desirable power plant,fuel combinations for hybrid electric vehicles. In the long term, fuel cells may dominate this application, but at least in the short term, proton exchange membrane fuel cells (PEMFCs) will not likely offer immediate substantial benefit over internal combustion (IC) engines. Environmentally friendly operation of the PEMFC results partly due to low-temperature operation but primarily due to the requirement of a clean fuel, hydrogen. In addition, the differential benefits from power plant choice can be overshadowed by the advantages obtained from hybrid electric vehicle technology and alternative fuels. Consequently, the fuel flexibility of IC engines provides an advantage over the relatively fuel inflexible PEMFC. The methane/hythane IC engine hybrid option, as developed and presented here, is a promising pathway that avoids the barriers encountered with conventional non-hybrid natural gas vehicles, namely range, power and fueling infrastructure difficulties. Dynamometer testing of the natural gas hybrid prototype on the certification FTP-72 duty cycle revealed very low emissions and mileage greater than 33 miles per gallon gasoline equivalent. This hybrid option utilizes a domestic, cost-effective fuel with renewable sources. With multi-fuel capability (methane, hythane and gasoline) it is also designed for use within the emerging hydrogen market. This hybrid option offers reliability and cost-effective technology with immediate wide spread market availability. Copyright © 2007 John Wiley & Sons, Ltd. [source] Shortest path stochastic control for hybrid electric vehiclesINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2008Edward Dean Tate Jr Abstract When a hybrid electric vehicle (HEV) is certified for emissions and fuel economy, its power management system must be charge sustaining over the drive cycle, meaning that the battery state of charge (SOC) must be at least as high at the end of the test as it was at the beginning of the test. During the test cycle, the power management system is free to vary the battery SOC so as to minimize a weighted combination of fuel consumption and exhaust emissions. This paper argues that shortest path stochastic dynamic programming (SP-SDP) offers a more natural formulation of the optimal control problem associated with the design of the power management system because it allows deviations of battery SOC from a desired setpoint to be penalized only at key off. This method is illustrated on a parallel hybrid electric truck model that had previously been analyzed using infinite-horizon stochastic dynamic programming with discounted future cost. Both formulations of the optimization problem yield a time-invariant causal state-feedback controller that can be directly implemented on the vehicle. The advantages of the shortest path formulation include that a single tuning parameter is needed to trade off fuel economy and emissions versus battery SOC deviation, as compared with two parameters in the discounted, infinite-horizon case, and for the same level of complexity as a discounted future-cost controller, the shortest-path controller demonstrates better fuel and emission minimization while also achieving better SOC control when the vehicle is turned off. Linear programming is used to solve both stochastic dynamic programs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Constructing a cognition map of alternative fuel vehicles using the DEMATEL methodJOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 1-2 2009Cheng-Wei Lin Abstract Environmental protection has taken serious notice of global warming. The Intergovernmental Panel on Climate Change (IPCC) has proved that CO2 is one of the factors for global warming. Furthermore, the majority of this emission comes from the vehicles using petroleum fuels. For this reason, alternative fuels become a very popular issue. There are many automakers and researchers endeavoring to develop alternative fuel vehicles (AFVs). There already have been many types of alternative fuels used in vehicles, such as electric vehicles (EVs), hybrid electric vehicles (HEVs), fuel cell (hydrogen) vehicles, natural gas vehicles (CNG), methanol vehicles, ethanol vehicles, and bio-diesel vehicles, etc. Different types of the alternative fuels have different characteristics to which attention should be paid. It is difficult for users to identify which one is the best choice for them to use. This problem concerns the characteristics of each alternative fuel. A lot of criteria and aspects related to the alternative fuels should be considered at the same time. In this study, we try to apply the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method to deal with the importance and causal relationships among the evaluation factors of AFVs. Results show the top three critical evaluation criteria are ,new car cost', ,cruising range', and ,fuel efficiency'; ,air pollution' is the key cause factor influencing others; and ,cruising range' is the key effect factor influenced by others. It is no accident that cost is the most critical factor for users. Consequently, it is suggested to automakers and researchers to carefully analyze the characteristics of each alternative fuel. Fuel efficiency is not only focused on by users, but also it will affect the cruising range. Air pollution is what users care about, so even zero-emission vehicles (ZEVs), which cost more but have lower emission and higher fuel efficiency, could be accepted. There seems to be no perfect AFV, but to endeavor on ZEVs will reduce some disadvantages. Copyright © 2010 John Wiley & Sons, Ltd. [source] Radical innovation in a small firm: a hybrid electric vehicle development project at Volvo CarsR & D MANAGEMENT, Issue 4 2010Hans Pohl The potential paradigmatic shift in technology from the internal combustion engine to electric propulsion via hybrid electric vehicles (HEVs) has been addressed by most automakers, and has produced very different outcomes. This paper uses the framework of core capabilities to discuss how the small automaker, Volvo Cars, made substantial progress in its HEV development using an approach based on limited resources and a low risk. A comparison with Toyota's successful but very resource-demanding Prius project reveals some factors contributing towards rapid development in a context of limited resources, including focused project objectives, tight collaboration with suppliers of the new technologies, reuse of existing technologies and an unaggressive, bottom-up approach to change the firm's values and norms and other core capability dimensions. This paper provides an empirical illustration of how a small company in a mature industry worked with radical innovation in a development project drawing on the combination of organizational slack, entrepreneurial employees and an extensive use of external (knowledge) suppliers. [source] | |||||||||||||