1,720,958 research outputs found
Predictive energy management strategies for hybrid electric vehicles: Ehorizon for battery management system
No full textThis paper presents the development of an Electronic Horizon (or eHorizon) strategy able to increase the electric range of a plug-in hybrid supersport vehicle, thanks to the detailed knowledge of the vehicle mission ahead (traffic lights timings, road profile, road congestion, dangerous events, etc.). Speed and load profiles estimation allows optimizing the thermal management strategies on the high voltage energy storage system, with a model-based approach. Due to the increasing diffusion of Advanced Driver Assistance Systems (ADAS) and Connectivity and Communication technologies (V2X) on vehicles, the reconstruction of the electronic horizon can today be considered feasible. eHorizon represents a detailed information of the mission ahead through the knowledge of traffic conditions and road characteristics. This detailed information along the route can be used by eHorizon function in short terms (0-250m, so-called short eHorizon) medium terms (250-1000m, so-called medium horizon), and long terms (over 1000m, so called long eHorizon). Long eHorizon information are normally used to adapt the powertrain strategies to optimize the energy usage
Development of Adaptive-ECMS and predictive functions for Plug-in HEVs to Handle Zero-Emission Zones Using Navigation Data
No full textThe paper deals with the reduction of pollutant emissions in urban areas by considering a Zero-Emission Zone (ZEZ) in which hybrid electric vehicles (HEVs) are allowed to be driven without using the internal combustion engine, as several cities have planned to realize in the next decades. Moreover, since vehicle connectivity has spread more and more in the last years, a vehicle-to-network (V2N) communication system has been taken into account to retrieve real-time navigation data from a map service provider and thus reconstructing the so-called electronic horizon, which is a reconstruction of the future conditions of the vehicle on the road ahead. The speed profile and the road slope are used as input for an on-board predictive control strategy of a plug-in HEV (PHEV). In particular, a dedicated algorithm predicts the amount of necessary energy to complete the city event in full-electric mode, giving a state of charge (SoC) target value. With this aim, an adaptive equivalent consumption minimization strategy (A-ECMS) has been modified to use navigation data for approaching the ZEZ with the target SoC. The paper finally quantifies the benefits of such an approach in terms of CO2 emissions by comparing it with a heuristic, rule-based one, which represents the standard OEM solution
Combined Optimization of Energy and Battery Thermal Management Control for a Plug-in HEV
No full textThis paper presents an optimization algorithm, based on discrete dynamic programming, that aims to find the optimal control inputs both for energy and thermal management control strategies of a Plug-in Hybrid Electric Vehicle, in order to minimize the energy consumption over a given driving mission. The chosen vehicle has a complex P1-P4 architecture, with two electrical machines on the front axle and an additional one directly coupled with the engine, on the rear axle. In the first section, the algorithm structure is presented, including the cost-function definition, the disturbances, the state variables and the control variables chosen for the optimal control problem formulation. The second section reports the simplified quasi-static analytical model of the powertrain, which has been used for backward optimization. For this purpose, only the vehicle longitudinal dynamics have been considered. The third section describes the Model-in-the-Loop environment of the vehicle, implemented in Simulink. In particular, the validation of the fuel consumption and the battery temperature models against experimental data is shown, and the original control strategies for the energy and thermal management are described, as well. This powertrain model is used to evaluate vehicle performance. As the powertrain architecture offers different torque split possibilities, different approaches to the powertrain control are considered, starting from the baseline rule-based controllers for both the thermal and energy management, to the combined-optimization based controllers. This paper shows a consistent fuel economy improvement due to energy management optimization, which becomes even larger if thermal management is included in the optimization algorithm
A predictive control strategy based on A-ECMS to handle Zero-Emission Zones: Performance assessment and testing using an HiL equipped with vehicular connectivity
Full text linkRecently, several metropolitan cities introduced Zero-Emissions Zones where the use of the Internal Combustion Engine is forbidden to reduce localized pollutants emissions. This is particularly problematic for Plug-in Hybrid Electric Vehicles, which usually work in depleting mode. So, the risk of not having enough energy stored to carry out the driving mission and then paying a fee is substantial. This work presents a viable solution by exploiting vehicular connectivity to retrieve navigation data of the urban event along a selected route. The battery energy needed, in the form of a minimum State of Charge (SoC), is calculated by a Speed Profile Prediction algorithm and a Backward Vehicle Model. That value is then fed to both a Rule-Based Strategy, developed specifically for this application, and an Adaptive Equivalent Consumption Minimization Strategy (A-ECMS). The effectiveness of this approach has been tested with a Connected Hardware-in-the-Loop (C-HiL) on a driving cycle measured on-road, stimulating the predictions with multiple re-routings. The tests have been conducted with different initial SoC values for each strategy, showing a maximum error in the SoC prediction of 2.4% and up to 26.1% of CO2 saving with the A-ECMS
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Hybrid Vehicle Hardware-in-the-Loop System with Integrated Connectivity for eHorizon Functions Validation
Full text linkUrbanization led to an increasing number of vehicles on the roads, resulting in more polluted air and more congested urban centers. This is being mitigated by the Hybrid Electric Vehicles equipped with telecommunication devices, which allow the implementation of predictive control strategies. This research is focused on the setup of an innovative and universal simulation environment for the development and the validation of predictive control strategies supported by Vehicle-to-Everything (V2x) connectivity. This helps the testing and validation of predictive control strategies, granting safety, reliability, and reproducibility. The simulation environment consists of a connected Hardware-in-the-Loop (HiL) system to test a supervisory controller (Hybrid Control Unit) where the predictive functions will be implemented. In addition to all the advantages of a conventional HiL layout, it can exchange real data from cloud service providers and nearby devices. The over-the-air interfaces between the powertrain controllers, the cellular network, and the Intelligent Transportation Systems (ITS-G5) are handled using a custom connectivity control unit with proprietary functionalities. Finally, this work presents the testing of the end-to-end communication for both the short- and long-range data exchange between real controllers
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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