Michele De Gennaro

Assessment of the potential of electric vehicles and charging strategies to meet urban mobility requirements

To integrate electromobility into modern urban mobility, it is necessary to assess the usability and potential of hybrid, plug-in and battery electric vehicles (BEVs) to meet urban mobility requirements, as well as their impact on electric distribution grid. Despite the progress that has been made in this field over the last decade, many technical issues still need to be addressed. This paper presents the results of a large-scale analysis of real-world driving data from activity databases, anonymously collected by Global Positioning System devices installed on conventional fuel vehicles. These data were processed to derive whether different types of BEVs and recharging strategies can meet urban mobility needs. The impact of the electric energy demand on the grid from a partially electrified urban fleet has also been addressed. The study involves approximately 28,000 vehicles, 4.5 million trips and 36 million kilometres in the Italian provinces of Modena and Firenze, monitored over a one-month period (i.e. May 2011). The results can contribute to assess the future integration of the electromobility in urban environment, their impact on the electric energy demand profile as well as possible scenarios for future European transport policies.

Experimental Investigation of the Energy Efficiency of an Electric Vehicle in Different Driving Conditions

Energy efficiency of electric vehicles (EVs) and the representativeness of different driving cycles are important aspects to address EVs performance in real-world driving conditions. This paper presents the results of an explorative tests campaign carried out at the Joint Research Centre of the European Commission to investigate the impact of different driving cycles on the energy consumption of an electric vehicle available on the market. The vehicle is a battery electric city-car which has been tested over the New European Driving Cycle (NEDC), the current version of the World-wide harmonized Light vehicles Test Cycle (WLTC) and the Worldwide Motorcycle emission Test Cycle (WMTC). The tests are performed at different ambient temperatures (namely +23 °C and −7 °C) with and without the use of the Heating Ventilation and Air-Conditioning (HVAC) system (in cooling and heating mode, respectively). The NEDC test was chosen being the driving cycle prescribed by the legislative type-approval procedure, while the WMTC and WLTC were chosen to investigate the energy demand of substantially different driving cycles, characterized by higher accelerations and a longer high speed phase duration. To further investigate the impact of the HVAC system on the energy consumption also some preliminary tests on the Mobile Air Conditioning (MAC) test procedure are presented. The results of these tests are compared with the fuel consumption and gaseous emissions results of one hybrid

European type-approval test procedure for evaporative emissions from passenger cars against real-world mobility data from two Italian provinces.

This paper presents an evaluation of the European type-approval test procedure for evaporative emissions from passenger cars based on real-world mobility data. The study relies on two large databases of driving patterns from conventional fuel vehicles collected by means of on-board GPS systems in the Italian provinces of Modena and Firenze. Approximately 28,000 vehicles were monitored, corresponding to approximately 36 million kilometres over a period of one month. The driving pattern of each vehicle was processed to derive the relation between trip length and parking duration, and the rate of occurrence of parking events against multiple evaporative cycles, defined on the basis of the type-approval test procedure as 12-hour diurnal time windows. These results are used as input for an emission simulation model, which calculates the total evaporative emissions given the characteristics of the evaporative emission control system of the vehicle and the ambient temperature conditions. The results suggest that the evaporative emission control system, fitted to the vehicles from Euro 3 step and optimised for the current type-approval test procedure, could not efficiently work under real-world conditions, resulting in evaporative emissions well above the type-approval limit, especially for small size vehicles and warm climate conditions. This calls for a revision of the type-approval test procedure in order to address real-world evaporative emissions.

Big Data for Supporting Low-Carbon Road Transport Policies in Europe: Applications, Challenges and Opportunities

Abstract Big data is among the most promising research trends of the decade, drawing attention from every segment of the market and society. This paper provides the scientific community with a comprehensive overview of the applications of a data processing platform designed to harness the potential of big data in the field of road transport policies in Europe. This platform relies on datasets of driving and mobility patterns collected by means of navigation systems. Two datasets from conventional fuel vehicles collected with on-board GPS systems have been used to perform an initial pilot study and develop its core algorithms. They consist of 4.5 million trips and parking events recorded by monitoring 28,000 vehicles over one month. The presented analyses address: (1) large-scale mobility statistics, (2) potential of electric vehicles in replacing conventional fuel vehicles and related modal shift, (3) energy demand coming from electric vehicles, (4) smart design of the recharge infrastructure and Vehicle-to-Grid, and (5) real-world driving and evaporative emissions assessment and mapping. The developed methodology and the presented outcomes demonstrate the potential of big data for policy assessment and better governance, focusing on the challenges and on the huge opportunities offered for future developments. This paper ultimately aims to show how big data can inspire smart policies together with public and private investments to enable the large scale deployment of the next generation of green vehicles, offering an unprecedented opportunity to shape policies for future mobility and smart cities.

Broadband Noise of Axial Fans: an Experimental and Computational Benchmark Study

The computation of turbomachinery airborne noise requires highly accurate numerical approaches to deal with the complexity of phenomena involved, such as turbulence and laminar-to-turbulent transition. The objective of this paper is to assess the prediction capability of an innovative LES technique, the Zonal LES, coupled with the Ffowcs Williams-Hawkings (FWH) acoustic analogy, in simulating the broadband noise of low speed axial fans. Two different LES formulations (the Wall Adapting Local Eddy-viscosity and the Wall Modeled LES) and different domain configurations (1-bladed with periodical boundary condition and 5-bladed configuration) have been compared with aerodynamic and acoustic measurements collected by the authors. Both LES formulations were able to provide reliable predictions. The 1-bladed configuration, due to numerical limitations, is not capable to properly predict the total sound pressure at the receiver locations even if it correctly reproduces the main phenomena related to broadband noise generation. The aerodynamic predictions of the 5-bladed configuration agree well with experimental aerodynamic PIV data. For a wide range of frequencies the far field sound pressure spectrum and its directivity are also in excellent agreement with experimental acoustic measurements. The numerical results have been used to single out the main noise source regions. It is found that low-frequency noise is mainly related to trailing edge fluctuations whereas mid-to-high frequency noise is mainly due to turbulent boundary layer fluctuations and laminar-to-turbulent transition.

Semi‐Empirical Modelling of Broadband Noise for Aerofoils

Turbulence related noise is widely recognized to be one of the most important aerodynamic noise sources for many applications and the development of computational tools for its modelling and prediction is an even more important target in many areas of applied engineering. On a general basis the noise generation mechanisms that can occur on an aerofoil surface can be classified in three main categories: Turbulent Boundary Layer‐Trailing Edge noise (TBL‐TE), the Laminar Boundary Layer—Vortex Shedding (LBL‐VS) noise and the Separation Stall (S‐S) noise, respectively related to the boundary layer turbulent eddies, to the boundary layer laminar instabilities and to the large vorticity that can be experienced for different Angle of Attacks, Reynolds and Mach numbers. Despite of the recent improvements of Computational Fluid Dynamics in the frame of turbulence modelling, the numerical computation of high Reynolds flow field turbulence for acoustic purposes is still a hard task to perform as it requires a time‐de...

A Numerical Investigation of the Laminar Instability Multi-Tonal Noise of Aerofoils

In the frame of applied aeroacoustics the numerical prediction of the aerofoil selfgenerated noise is key issue for a number of applications in aeronautics, vehicle industry and wind energy. Aerofoil airborne noise has been widely approached in several studies and well characterized for a number of flow conditions. Nevertheless there are still many cases where it is not yet completely clear how the flow noise is generated. The objective of this paper is to perform a deep and accurate analysis of the noise generated by laminar instabilities of the boundary layer arising for Reynolds numbers ranging approximately between 0.6M and 1.1M. The test-case chosen is the NACA 0012 aerofoil which has been investigated by means of transient RANS aerodynamic simulations coupled with the Ffowcs Williams and Hawkings acoustic analogy and a Finite Element based approach to Lighthill’s equation for the acoustic computations. Numerical sound pressure spectra have been compared to experimental data achieving a very good agreement for different flow speeds and Angles of Attack. The numerical simulations performed have been able to capture the sharply peaked multi-tonal acoustic phenomena which arise from the flow instabilities evolving within the boundary layer proving the high potentialities of such numerical approaches in the frame of the applied aeroacoustics.

Modeling and Validation of Lithium-Ion Battery based on Electric Vehicle Measurement

This contribution deals with the modeling and validation of multi-physical battery-models, by using the programming language Modelica. The article presents a battery model which can be used to simulate the electric, thermal and aging behavior of a lithium-ion traction battery of an EV in different load conditions. The model is calibrated with experimental data of an electric vehicle tested on a chassis dynamometer. The calibration parameters, that are the open circuit voltage, the serial resistance and the resistance and capacitance of two serially connected RC-circuits, are used to configure the electric equivalent circuit model of the battery. The calibration process is based on a best-fit of the measured data from one test, while the validation is made by comparing measured and simulated battery voltages of a different battery load cycle. The comparison between simulations and experiments shows that this model is capable to accurately reproduce the real-world behavior of the battery, providing the scientific community with a novel approach for design and optimization purposes.

Numerical Prediction of Laminar Instability Noise for NACA 0012 Aerofoil

Aerofoil self‐generated noise is recognized to be of fundamental importance in the frame of applied aeroacoustics and the use of computational methods to assess the acoustic behaviour of airframe components challenges an even larger community of engineers and scientists. Several noise generation mechanisms can be found which are mainly related to the physical development of turbulence over the boundary layer. They can be classified in 3 main categories: the Turbulent Boundary Layer—Trailing Edge noise (TBL‐TE), the Laminar Boundary Layer—Vortex Shedding (LBL‐VS) noise and the Separation Stall (S‐S) noise. The TBL‐TE is mainly related to the noise generated by turbulent eddies which develop into the boundary layer and usually exhibits a broadband spectrum. The LBL‐VS is related to laminar instabilities that can occur within the boundary layer which are responsible for a very late transition and generate a typical peaked tonal noise, while the S‐S noise mainly results from the development of large vortices ...