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The aim of this study is to investigate the effect of ethanol-gasoline mixtures on cold emissive behavior of commercial motorcycles. For the newly sold motorcycles, equipped with a three-way catalyst and electronic mixture control, CO and HC cold additional emissions, if compared with those exhausted in hot conditions, represent an important proportion of total emissions. On the other hand, ethanol is known as potential alcohol alternative fuel for spark ignition engines, which can be blended with gasoline to increase oxygen content and then to decrease emissions. From this explanations, a research on cold start emissions of motorcycles using ethanol-gasoline mixtures was conducted. In this specific study, a motorcycle (belonging to the Euro-3 legislative category) was operated on a chassis dynamometer and driven according to the ECE driving cycle to analyze the exhaust cold extra emissions of CO and HC, while the ethanol was mixed with unleaded gasoline in three different percentages (10, 20 and 30 % v/v). Results of the tests and the application of a calculation procedure, designed to model the cold start transient behavior of motorcycles, indicate that CO and HC cold start extra emissions using ethanol-gasoline blended fuels decrease compared to the use of unleaded gasoline

Ethanol can be used as an alternative fuel for spark-ignition (SI) engines to increase the octane number and oxygen content of ethanol/gasoline blends, thereby reducing dependence on fossil fuels and the exhaust emissions of incomplete combustion products. Although it is widely agreed that ethanol can reduce CO and HC exhaust emissions, the literature on ethanol and NOX emissions is far from conclusive; hence there is a need for an in-depth, updated review of ethanol/gasoline blends in SI engines and the relative production of NOX emissions. In light of that, the present work aims to provide a comprehensive literature review on the current state of ethanol combustion in SI engines to shed definitive light on the potential changes in NOX emissions under various operating conditions. The first part of this paper discusses the feasibility of ethanol as an alternative transportation fuel, including world production and ethanol production processes. The physicochemical properties of ethanol and gasoline are then compared to analyze their effects on combustion efficiency and exhaust emissions. Then, the pathways of NOX formation inside the cylinder of SI engines are discussed in depth. Finally, we review and critically discuss the effects of ethanol concentration in blends and different engine parameters on NOX formation.

This paper explains a numerical optimization of a novel screw expander-based solar thermal electricity plant to evaluate the energetic benefits in specific case studies. In the proposed solar electricity generation system, which is based on the steam Rankine cycle, water is used as working fluid and storage, parabolic trough collectors as a thermal source and screw expander as power machine. Such solar system offers major advantages over conventional power plants adopting steam turbines: low operating pressures, good exploitation of low temperature heat sources, acceptable efficiency in energy conversion with steam-liquid mixtures and reduced size. Since screw expanders can operate at off-design working conditions in several situations when installed in direct steam generation solar plants, the chief purpose of the present study is to develop a thermodynamic model to analyse the energy performance of the planned solar power system when off-design operating conditions befall. To assess maximum efficiency of the whole power plant at part-load operating conditions, numerical optimization is then performed in a specific range of fluctuating evaporation temperatures under fixed condensation pressures. Keywords: Steam screw expander, Solar thermal power efficiency, Direct steam generation, Part-load behavior, Polytropic expansion phase

The objective of this study is to investigate the effect of bioethanol-gasoline blends on the exhaust emissions and engine combustion of a four-stroke motorcycle. Ethanol is known as an alternative fuel for spark-ignition engines and is suitable for making blends with gasoline, increasing the oxygen content and decreasing emission of incomplete combustion products. An experimental investigation was performed on a Euro 3 large-size motorcycle fuelled with commercial gasoline and bioethanol/gasoline blends (range of bioethanol 5% v to 30% v). Regulated and unregulated emissions and fuel consumption were quantified over the execution of chassis-dynamometer tests. The combustion analysis, realized by acquiring the pressure cycle inside the cylinder, highlights the auto adjustment of the engine control unit and guarantees use within the same parameters of several tested fuels, with the except of fuel injection time, which increases with increasing ethanol percentage. A significant reduction in carbon monoxide and particle number is associated with the ethanol content of the fuel. Volatile organic compounds, mainly alkanes and aromatics, are not substantially influenced by the bioethanol content of the fuel. The contribution of carcinogenic benzene ranges between 2 and 5%.

Screw expanders are volumetric machines particularly suitable in energy conversion with steam–liquid mixtures and for the exploitation of low temperature heat sources. This study explored the main criteria to evaluate the thermodynamic advantages and exergetic assessment of an innovative solar electricity generation system: Screw expanders are utilized as power machines and parabolic trough collectors as a thermal source. Such a direct steam generation solar system, which is based on the Rankine cycle, offers benefits in comparison with usual power plants with dynamic expanders: The best exploitation of low temperature heat sources, satisfactory thermal efficiency with steam–liquid mixtures, lower evaporation pressures, and reduced size. Under real working conditions, screw expanders can work at part-load operating conditions; thus, the chief purpose of the present paper was to analyze the exergetic advantages of the planned solar power system when solar radiation and off-design working conditions fluctuate. Initially, the polytropic expansion phase with a specific numerical model is described to evaluate the energy losses that affect the thermodynamic performance of screw expanders when installed in the planned renewable energy power plant. Subsequently, to explore the exergy harnessing in the exhausted steam at off-design working conditions and then to appraise the maximum exergetic efficiency of the proposed screw expander-based solar thermal electricity plant, numerical optimization was performed in a broad range of evaporation and condensation temperatures.

AbstractIn Campania region, southern Italy, a National Interest Priority Sites (NIPS) was identified: “Litorale Domitio-Agro Aversano” NIPS L.426/98, that includes a large part of the polluted agricultural land, belonging to more than 61 municipalities in the Naples and Caserta provinces. This paper represents a synthesis of a study developed for a LIFE project (LIFE11/ENV/IT/275–ECOREMED): “Implementation of Eco-Compatible Protocols for Agricultural Soil Remediation in Litorale Domizio-Agro Aversano NIPS”. As well known, the pollutants of the air may have an impact on the soil pollution; the contribution of the paper to this LIFE project is to provide the environmental characterization of the area, estimating the total annual emissions of the main air pollutants (CO, VOC, NOX and PM10) in the area under investigation, with municipal spatial disaggregation. The amounts of air pollutants emitted from various sources in this area were obtained through direct and continuous measures for the principal industrial systems, while for diffused sources the emissions were estimated on the basis of opportune activity indicators and fixed emission factors concerning specific emissive activities.

The purpose of this paper is the assessment of the environmental air pollution in a very densely inhabited area in the southern Italy, which is characterised by serious general contamination. Because the air pollution may have an impact on human health, this area was identified in 1998 as a National Interest Priority Site and comprises a large part of agricultural lands belonging to over 60 municipalities between Naples and Caserta provinces. This study characterises the air pollution affecting this area by estimating the total annual emissions of the major pollutants (CO, NOX, VOC, PM and heavy metals) and showing their municipal spatial disaggregation. In this study a bottom-up methodology was employed, then focusing at regional level instead of national and comprising local and specific parameters. The pollutants emitted from several sources in the area under investigation were obtained by direct measurements of the principal industrial point sources, whereas the emissions from diffuse sources were calculated on the basis of local activity indicators and specific emission factors concerning the relevant activities in this area. The results obtained in this research have identified local critical factors.