•Up-to-date evaluation of graphene-based gas sensors.•Hybrids of graphene with noble metals, metal oxides, and conducting polymers.•Systematic comparison of gas-sensing principles graphene-based ...hybrids.•Systematic comparison of gas-sensing properties of graphene-based hybrids.•Presentation of future outlook for graphene-based hybrid gas sensors.
Gas sensors can detect combustible, explosive and toxic gases, and have been widely used in safety monitoring and process control in residential buildings, industries and mines. Recently, graphene-based hybrids were widely investigated as chemiresistive gas sensors with high sensitivity and selectivity. This systematic review is therefore timely and necessary to evaluate the success of graphene-based hybrids in gas detection and to identify their challenges. We review the sensing principles and the synthesis process of the graphene-based hybrids with noble metals, metal oxides and conducting polymers to achieve better understanding and design of novel gas sensors. Our review will assist researchers to understand the evolution and the challenges of graphene-based hybrids, and create interest in development of gas-sensing techniques.
This article presents an energy management strategy (EMS) design and optimization approach for a plug-in hybrid electric vehicle (PHEV) with a hybrid energy storage system (HESS) which contains a ...Li-Ti-O battery pack and a Ni-Co-Mn battery pack. The EMS shares power flows within the hybrid powertrain, and it employs a dual fuzzy logical controller whose inputs are predictions for PHEV powertrain states. An elitist nondominant genetic algorithm using a model in loop simulation approach as fitness functions is implemented to multiobjective optimization for the EMS under worldwide light-duty test cycles. The optimal objectives are improving PHEV mileage, minimizing battery packs capacity fades, reducing HESS degradation inconsistency, and minimizing driving cost unit distance. A hardware in loop test bench has been established to verify EMS performances in embedded systems. The test results under new European driving cycles demonstrate that optimized EMSs remain appropriate for different driving cycles and their performances are close to dynamic programming based offline optimal solutions. Due to the contributions of both the HESS and the optimized EMS, the PHEV energy efficiency has been improved by 1.6%-2.5% and the PHEV energy storage system cycle life can be improved by 159%-203%.
•The HPS classification of PEMFC-HEV was reviewed.•The structures of the HPS system were expressed by drawing intentions.•The EMSs of PEMFC-HEV were investigated and studied in recent years.•The ...characteristics of different control strategies were summarized.
Nowadays, there is a great shortage of non-renewable energy, and the environmental problems such as air pollution caused by automobile exhaust are very serious. The traditional fuel vehicle has been unable to meet the current human needs, so more and more people are concerned about the development of the hybrid electric vehicles (HEVs). Based on proton exchange membrane fuel cell (PEMFC) is a new clean energy without pollution, PEMFC-HEV has a great potential for development. In this review, we have made a comprehensive research on energy management strategy (EMS) of the hybrid power system (HPS) for PEMFC-HEV in recent years. This paper focuses on the EMS of PEMFC as the main power source, the battery and the supercapacitor (SC) as the auxiliary energy in HEV. In this research, the classification of PEMFC-HEV is introduced in detail, and the advantages and disadvantages of various combinations of HPS are summarized. In addition, according to the different requirements and optimization targets of PEMFC-HEV, this paper makes a deep study of the current PEMFC-HEV hybrid system model, and the EMS developed by the researchers. Besides, the simulation and experimental results are compared with each other. From the perspective of strict evaluation, the existing technology can perform more or less. However, high efficiency and optimization performance still fail to achieve high goals. Therefore, the current problems and main control strategies of PEMFC-HEV are discussed and summarized, which is helpful for the development of PEMFC-HEV research in the future. The review will be expected to bring more efforts to the future development of PEMFC-HEV, including faster dynamic response, longer service lifetime, economic optimization, and high efficiency for the PEMFC system.
The increasing concern regarding environmental issues has led to the adoption of stringent regulations worldwide to facilitate the urgent move towards green mobility and sustainable transportation. ...In this regard, electrified powertrains are bound to replace conventional thermal engines to reduce greenhouse gases and pollutant emissions. The synergy between the internal combustion engine and the electric unit in hybrid electric vehicles (HEVs) significantly reduces fuel consumption and emissions while maintaining high vehicle performance and driving comfort. Moreover, unlike pure electric vehicles, the hybrid electric powertrain fulfills even the most demanding energetic requirements, ranging from light- and heavy-duty vehicles to agricultural machinery, vessels, and aircraft, thus becoming the optimal sustainable solution in the short term. Nonetheless, the full potential of HEVs can only be exploited using a multidisciplinary approach to design the mechanical and electrical equipment and implement the optimal energy management strategy. This Special Issue, “Frontiers in Hybrid Vehicles Powertrain”, provides a broad perspective on the current challenges and research trends of the hybrid electric powertrain collecting nine peer-reviewed papers dealing with the main mechanical, electrical, controls, and energetic issues of HEVs.
•Two hybrid powertrains evaluated under conventional and low temperature combustion.•Parallel hybrid provides the major fuel consumption gain for both combustion modes.•Mild hybrid allows ...intermediate fuel consumption compared to conventional and parallel.•CO2 reduction with Parallel hybrid thanks to pure electric mode in city driving.•Ultra-low NOx and soot emissions achieved with the low temperature hybrid vehicle.
The stringent regulations, increased global temperature and customer demand for high fuel economy have led to rapid developments of different alternative propulsion solutions in the last decade, with special attention to the electrified vehicles. The combination of electric machines with conventional powertrains allows to diversify the powertrain architectures. In addition, alternative combustion modes as reactivity controlled compression ignition (RCCI) have been shown to provide simultaneous ultra-low NOx and soot emissions with similar or better thermal efficiency than conventional diesel combustion (CDC). Therefore, the combination of both technologies creates a promising horizon to be implemented in commercial vehicles of the near future. In this work, experimental and numerical simulations were combined to study the potential of the parallel full hybrid electric vehicle (P2-FHEV) and mild hybrid vehicle (MHEV) to obtain lower fuel consumption and NOx emissions than a conventional powertrain in the Worldwide Harmonized Light Vehicles Cycle (WLTC). The hybrid vehicles are simulated with both CDC and diesel-gasoline RCCI combustion engines as power source. Each powertrain was optimized in terms of components (battery, electric motors…) capacity, internal combustion engine operative points, energy management strategy and gear ratios. The results show a significant fuel consumption reduction as the complexity of the hybrid system increases. The parallel architecture, which represents the most complex hybrid system tested in this work, allows obtaining a fuel consumption reduction of around 20% as compared to CDC. The dual-mode CDC-RCCI concept showed improvements in NOx and soot emissions with comparable values in terms of energy consumption and CO2 emissions than CDC. Additionally, the mild hybrid technology with the functionality of start-stop, torque assist and regenerative braking showed an acceptable balance between complexity and fuel consumption gain.
Summary
A worldwide shift headed for a greener and low emissions will necessitate remarkable advancement in the way in which the energy is being produced and used. The factors such as climate changes ...induced by pollution, progressively more strict emissions norms for vehicles, depletion of petrol/diesel along with instability in their prices for transportation systems, play a vital role in the improvisation of technology involved in conventional vehicles. The hybrid electric vehicles (HEVs) are on the peak of the list of choices available for clean vehicle technologies. The various architectures of HEV, different methodologies of hybrid vehicle, are focused in this paper. The design criteria and optimization techniques with reference to the driving cycle is also elucidated. The various electric drives used for HEV are discussed in this paper. Also, the different electric propulsion systems are explained. To improve the fuel economy and emission of hybrid power system, control strategies are very significant. Researchers concentrate in optimizing the performance of HEV.
The hybrid electric vehicle (HEV) and electric vehicle (EV) are the way out to decrease the emission and increase the fuel efficiency globally. The various architectures of HEV, different methodologies of hybrid vehicle and various electric drives used for HEV are focused in this paper.
Variability and intermittency are some of the main features that characterize renewable energy sources. Intermittency usually includes both predictable and unpredictable variations. The many ...drawbacks of intermittency of renewable sources can be overcome by considering some special design considerations. Integrating more than one renewable energy source and including backup sources and storage systems are among the few measures to overcome these drawbacks. These additional design considerations usually increase the overall cost of the renewable system. Furthermore, the presence of more than one energy supply/storage system requires the control of energy flow among the various sources. Therefore, optimizing the size of the components and adopting an energy management strategy (EMS) are essential to decreasing the cost of the system and limiting its negative effects. The energy management strategy is commonly integrated with optimization to ensure the continuity of load supply and to decrease the cost of energy production. Therefore, energy management is a term that collects all the systematic procedures to control and minimize the quantity and the cost of energy used to provide a certain application with its requirements. The energy management strategy usually depends on the type of energy system and its components. Various approaches and techniques have been used to develop a successful energy management strategy. In this paper, a comprehensive review of the approaches proposed and used by authors of many papers is conducted. These approaches include both the standalone hybrid renewable energy systems and the grid-connected hybrid renewable systems. More attention is focused on popularly used techniques to address the features of each system. The selected papers in this review cover the various configurations of the hybrid renewable energy systems for electric power generation only.
There is a great appeal to develop an omnipotent player combining lithium‐ion batteries (LIBs) with the capacitive storage communities. Hybrid capacitors as a kind of promising energy storage device ...are attracting increasing attention in the main playground in recent years. Unlike supercapacitors (SCs) and LIBs, hybrid capacitors combine a capacitive electrode with a Faradaic battery electrode. In these hybrid cells, the capacitive electrode brings the power while the energy mainly comes from the Faradaic one. Numerous efforts have been conducted in the past decades; however, the research about hybrid capacitors is still at its infancy stage, and it is not expected to replace LIBs or SCs in the near future utterly. Here, the advances of hybrid capacitors, including insertion‐type materials, lithium‐ion capacitors, and sodium‐ion capacitors, are reviewed. This review aims to offer useful guidance for the design of faradic battery electrodes and hybrid cell construction. Brief challenges and opportunities for future research on hybrid capacitors are finally presented.
The latest status and advancement regarding hybrid capacitors have been elaborated, including history walk, charge storage mechanisms, scientific fundamentals, insertion‐type electrode materials architecture, and full cell design. The fundamental science behind the challenges, and potential solutions toward the goals of a long calendar life and/or high energy density future, are discussed in detail.
Hybrid sodium‐based dual‐ion capacitors (NDICs), which integrate the advantages of supercapacitors and sodium‐ion batteries, have attracted tremendous attention recently. In this work, hybrid ...sodium‐based dual‐ion capacitors are successfully developed with nitrogen‐doped microporous hard carbon as the cathode and soft carbon as the anode. N‐doping is beneficial to the functional groups, porous structure, and electric conductivity of hard carbon. Hybrid NDICs possess a wide voltage range (0.01–4.7 V), high‐energy density of 245.7 W h kg−1 at a power density of 1626 W kg−1, long cycle life (1000 cycles), and outstanding rate performance.
Hybrid sodium‐based dual‐ion capacitors (NDICs) are successfully developed with nitrogen‐doped hard carbon as the cathode and soft carbon as the anode. Hybrid NDICs exhibit high capacity, excellent cycling ability, ultrahigh energy and power densities, and with fast charging and slow discharging performance (the hybrid NDICs can be fully charged in 40 s and discharged over more than 1200 s).
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