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Within the “Industria 2015” Italian framework program, the HI-ZEV project has the aim to develop two high performance vehicles: one full electric and one hybrid. This paper deals with the electric energy storage (EES) design and testing of the hybrid vehicle. A model of the storage system has been developed, simulating each cell like an electric generator with more RC circuits in series. To take account of the heat transfer, a forced convection model has been used with the air speed proportional to the vehicle speed. The model had two calibration steps: the first has determined the electrical parameters of the model (open voltage circuit, internal resistances and capacitors); the second to calibrate the heat transfer model. The first calibration has been made on a climatic chamber at 23 °C discharging one single module with different constant currents from 5C (5 times the nominal capacity) to 25C and charging with currents in the range from 1C to 5C.

The adoption of composed (hybrid) lead acid battery-supercapacitor (SC) storage systems is able to improve performances (availability, durability, range) of an electric microcar. As a matter of fact, the supercapacitors extend the operation time not only by improving the energy efficiency (thanks to a higher contribution of regenerative braking), but also by reducing the power down caused by voltage drop at higher discharge rates. The integration of battery with supercapacitors requires careful analysis and calculation of the relationship between battery peak power and size of the SC bank, needed to have a balanced composition of the hybrid storage system. For this purpose, the optimization process, summarized here, is based on the combination of a conventional lead-acid battery and a commercial SC, with the vehicle running the ECE15 driving cycle.

This paper reports the results of experimental tests performed at ENEA (Italian National Agency for New Technologies, Environment and Sustainable Development) in its “Casaccia” Energy Research Center to evaluate the energetic and environmental performances of a Heavy-Duty Compressed Natural Gas (HD CNG) engine fuelled with a hydrogen-methane blend of 15% in volume. A lean burn Mercedes 906 LAG engine has been optimized properly calibrating ECU engine maps regarding both ignition advance and air to fuel ratio (AFR). It was therefore possible to correct ignition advance to take into account the faster combustion speed given by the hydrogen content of the fuel mixture. Equivalence ratio (Lambda) has instead been modified in order to minimize the NOx emissions. All the tests were performed on a steady engine test-bed focusing the attention on the most important parts of the engine maps.

Hybrid electric vehicles (HEVs) are worldwide recognized as one of the best and most immediate opportunities to solve the problems of fuel consumption, pollutant emissions and fossil fuels depletion, thanks to the high reliability of engines and the high efficiencies of motors. Moreover, as transport policy is becoming day by day stricter all over the world, moving people or goods efficiently and cheaply is the goal that all the main automobile manufacturers are trying to reach. In this context, the municipalities are performing their own action plans for public transport and the efforts in realizing high efficiency hybrid electric buses, could be supported by the local policies. For these reasons, the authors intend to propose an efficient control strategy for a hybrid electric bus, with a series architecture for the power-train.

A feasibility study related to the realization of a fuel-cell medium-size bus, has been committed by the Tuscany Region with the support of the municipality of Florence and Bologna, and realized by the association ONLUS I2T3 (Industrial Innovation Through Technological Transfer), ENEA, the Italian National Agency for Energy and Environment, and CAM, Carrozzeria Autodromo Modena, an Italian company leader in the field of eco-compatible solutions in the public transport sector. A hybrid traction system has been chosen, to reduce costs and to boost the vehicle efficiency thanks to regenerated energy during deceleration. The paper deals with the general strategic framework, the mission, the vehicle design and, finally, costs and benefits of FCHEVs, compared to conventional buses and hybrid-electric buses with motorgenerators.

When the first hybrid vehicles were commercialized in the early '90, traction lead-acid batteries were used as on board storage system, and their limits in this application were soon complained from users and recognized by manufacturers. Therefore the battery industry has developed specific high-power lead-acid batteries, which constitute an industrialized and economic alternative to the alkaline batteries (Ni-Cd, Ni-MeH). Under the direction and funding support of the Commission of the European Community, the R&D Organization EUCAR (European Council for Automotive Research, a collaborative partnership of most European car manufacturers), has been conducting an autonomous characterization activity of these high-power systems using agreed test procedures, through bench tests carried out by different independent laboratories throughout Europe.

The paper deals with the study of an original on-board power system that combines battery, ultracapacitors (UCs) and a Fuel Cell. The project was funded by the Italian Government in the framework of the new Hydrogen Research Project and is conceived as the first step of a project involving ENEA, (Italian National Agency for New Technology, Energy and Environment, and University of Rome “Roma 3”, aimed at developing a Fuel Cell-powered drive train, for a city-car. It foresees the realization of the drive train in a prototype version, powered by a 5 kW DeNora Fuel Cell, and its testing beside the ENEA laboratories in Casaccia. The report highlights the storage system design phase, emphasising the role that ultracapacitors could fulfill in a near future thanks to their peculiar characteristics, and point at an optimisation method, based on the “simplesso method”, for the technical and economic sizing of such a hybrid storage system.

ENEA is studying innovative vehicles such as pure electric and hybrid-electric vehicles, aiming to increase their energy efficiency and to reduce pollutant emissions. As part of such activities, a quite large demonstration project for verifying technical and economical viability of hybrid buses under real public transport operation conditions, has been carried out. Furthermore, a controller for an electric hybrid vehicle has been developed that allows to achieve a further 30% fuel economy improvement. The results of such activities are the input information of the TREMOVE model to investigate the potential impact of electric hybrid vehicle deployment in an Italian city, as a case study. The positive effects of new hybrid vehicle introduction for freight transport in terms of fuel saving and emission reduction, have been also investigated.

Among the research and development subjects of ENEA (Italian National Agency for New Technology, Energy and Environment) an important theme is the study of innovative vehicles with high energy efficiency and low emissions. ENEA has set up an infrastructure in order to execute research and development activity for hybrid and electrical vehicles. The paper deals with features and working methods throughout the testing campaign on the ALTRA minibus drive-train, a 6m. series hybrid developed by IVECO and ANSALDO. The test demonstrated that the energy consumption is strong correlated to the power management strategy. Subsequently, a testing work was carried on with a controller developed by ENEA and University of Pisa, by using the roll bench of ENEA, while the IVECO tested on the road an other control system. All these tests convalidates the need of a controller to achieve fuel economy.