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This paper presents the experimental results obtained on Fuel Cell System designed and realized in Istituto Motori and based on 16 kW PEM (Proton Exchange Membrane) stack. This activity is part of the HBUS Project, whose goal is the realization of a midi-bus for public transportation in urban areas based on fuel cell technology. This Project involves several private and public partners, comprising Istituto Motori as research institution, I2T3 (Industrial Innovation Through Technological Transfer) agency for technological innovation and project management, together with public transportation companies and vehicle component makers.

This paper reports the results of a study on adsorption properties of zeolitic materials with different pore opening and Si/Al ratio towards engine cold start hydrocarbon emissions. Some selected zeolites were deposited on cordierite honeycomb support by a novel technique. Dynamic adsorption tests were performed at the engine exhaust on both commercial and specifically synthetised powder samples and on deposited zeolites. In order to obtain indications on selectivity properties of the different materials, equilibrium isotherm curves and dynamic tests were carried out for three model hydrocarbons (ethylene, isobutene, toluene), considered as representative of the most concentrated compounds detectable at engine start-up. The aim was to understand how the physico-chemical characteristics of the adsorbent material can affect its trapping capability in adsorbing all the types of hydrocarbons present in the engine exhaust.

The aim of this paper is to analyse the main concerns related to on board hydrogen catalytic production of fuel cell electric vehicles, starting from different gaseous and liquid fuels. In particular, limits and potentialities of hydrocarbons and alcohols have been examined, considering steam reforming and partial oxidation reactions with reference to emission and efficiency implications. Preliminary results of an experimental investigation on steam reforming of natural gas and liquid hydrocarbons are reported. Furthermore, a mono-dimensional mathematical model of methane steam reformer based on first order kinetics has been developed to simulate the experimental results.

This paper reports the results of a study on basic adsorption properties of three different zeolitic materials (HZSM5, Silicalite, HY) towards hydrocarbons present at engine exhaust during cold start. Equilibrium isotherm curves at room temperature are presented for three model hydrocarbons (ethylene, isobutene, toluene), considered as representative of the most concentrated compounds detectable at engine start-up. Breakthrough curves, obtained at different temperatures by flow adsorption tests with the selected hydrocarbons, are also discussed. Finally the results of flow adsorption tests performed on the three zeolitic materials at engine exhaust are shown. The aim is to understand how the physico-chemical characteristics of the adsorbent material can affect its trapping capability in adsorbing all the types of hydrocarbons present in the engine exhaust.

Three developmental catalytic converters, provided by different companies, were tested at the exhaust of a SI (spark ignition) NG (natural gas) engine for bus application. The catalysts were all based on noble metals: Pt (platinum), Pd (palladium), Rh (rhodium) and differed in size, metal loading and active phase composition. Emission evaluation was performed according to the European ECE-R49 procedure (13 mode cycle), in stoichiometric and lean-burn conditions. In addition to regulated emission measurement, speciation of NMHC (non-methane hydrocarbons) and carbonyl compounds was performed. The results showed that all the catalyst compositions considered allowed the European emission limits to be complied when the engine operated in stoichiometric conditions, while the overall best performance in the lean region was obtained on the catalyst with noble metal composition Pd:Rh=21:1.

Natural gas is a viable alternative fuel to obtain low exhaust emissions. A heavy duty DI Diesel engine was converted to Otto cycle natural gas operation. Two alternative solutions were compared: lean-burn technology; stoichiometric feed with three-way catalyst and EGR. Power and efficiency were similar for the two above solutions, and exhaust temperature resulted similar to the diesel engine in both cases due to the diluted operation. The lean bum engine met EURO II ECE-R49 limits except for total hydrocarbons. Stoichiometric engine emissions resulted much lower than the limits. Particulate emissions were quite negligible for the two solutions.

The present paper reports the results of an experimental investigation carried out on a four-stroke single- cylinder D.I. diesel engine (100 x 95mm bore x stroke) with the aim to evaluate the effects of a four-lobe square combustion chamber on the gaseous and particulate emissions. Fluid-dynamic behaviour of the axisymmetric toroidal and four-lobe square chambers was investigated by Laser Doppler Anemometry. Engine tests at 2000 and 3000 rpm for different start of combustion (SOC) and A/F ratio are reported. Particulate, HC and NOx emission index measured under different operating conditions are given. In addition, the volatile content of the particulates produced from the two chambers at various engine operative conditions was measured by thermogravimetric analysis (TGA). Finally, the catalytic activity of a metal-oxide-based catalyst in the combustion of particulate was also evaluated by TGA.