In this paper, a theoretical/experimental analysis of a new measurement system of the chain stren... more In this paper, a theoretical/experimental analysis of a new measurement system of the chain strength is described. Such system is functional for the control of the electrically assisted bicycles which are characterized by a driving torque due to the contribution of both electric motor and rider. The electrical assistance is commonly regulated taking into account informations such as the chain ring rotation, the bicycle speed and/or the torque given by the rider. As a consequence, suitable measurements have to be made on board in order to handle the assistance performances and to improve drivability.
This study derives from the need to evaluate the impact on the urban air quality of two-wheeler v... more This study derives from the need to evaluate the impact on the urban air quality of two-wheeler vehicular class. Mopeds and motorcycles, in fact, are increasingly used in recent years, representing a great share of motor-powered vehicles in urban environment. This paper is finalized at the examination of the emissions of the last generation motorcycles, contributing broadly to extend knowledge of twowheeler emission behavior, with reference to cold and hot operating conditions. For this aim, an experimental investigation was performed on a medium-size motorcycle belonging to the Euro-3 statutory category, evaluating the exhaust emissions of regulated pollutants. This scooter was tested on a dynamometer bench both on a type approval test cycle and on real-world test cycles in order to study the influence of driving cycles on the emission levels. The statistical processing results of the experimental data were compared with recent emission models for estimating emissions from road tra...
Abstract— The paper describes the development of an electric bicycle mathematical model and its e... more Abstract— The paper describes the development of an electric bicycle mathematical model and its experimental validation. The modelling procedure has focused on the vehicle and the electric motor dynamics. The model has been particularized with respect to an innovative electric bicycle. Preliminary experimental tests have involved the characterization of a novel chain strength sensor and then, different drive conditions have been assigned and the results have been collected in order to carry on the parameter identification. Successively, novel experimental results have been adopted to validate the proposed model. The validation procedure has highlighted the goodness of the adopted approach, allowing to employ the mathematical model for predictive analysis of the electric bicycle performances in simulation environment.
Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide ... more Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to ...
Screw expanders are volumetric machines particularly suitable in energy conversion with steam–liq... more 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 wor...
In the most recent years, renewable sources are becoming increasingly crucial owing to both the s... more In the most recent years, renewable sources are becoming increasingly crucial owing to both the stocks of fossil fuels being depleted and environmental problems around the globe. This study describes the environmental assessment of thermal power plant-based trigeneration systems fuelled by renewable energy sources for district heating/cooling system. First, the paper examines the thermal and refrigeration requests of a possible new urban area with electricity, cooling and heating provided by a new trigeneration power system; this study is performed considering a trigeneration plant based on the internal combustion engines fuelled by renewable vegetable oil. Subsequently, a numerical assessment is achieved in order to evaluate the environmental impact on the neighboring area of the trigeneration system. The results of these numerical simulations show that the impact of this power plant on air quality state is not significant in this area. As a result, this kind of trigeneration power...
Abstract In the latest years the effect of powered two-wheelers on air polluting emissions is gen... more Abstract In the latest years the effect of powered two-wheelers on air polluting emissions is generally noteworthy all over the world, notwithstanding advances in internal combustion engines allowed to reduce considerably both fuel consumption and exhaust emissions of SI engines. Nowadays, in fact, these vehicles represent common means of quotidian moving, serving to meet daily urban transport necessities with a significant environmental impact on air quality. Besides, the emissive behavior of the two-wheelers measured under fixed legislative driving standards (and not on the local driving conditions) might not be sufficiently representative of real world motorcycle riding. The purpose of this investigation is a deeper research on emissive levels of in-use motorcycles equipped with last generation SI engines under real world driving behavior. In order to analyze the effect of vehicle instantaneous speed and acceleration on emissive behavior, instantaneous emissions of CO, HC and NO X were measured in the exhaust of a four-stroke motorcycle, equipped with a three-way catalyst and belonging to the Euro-3 legislative category. Experimental tests were executed on a chassis dynamometer bench in the laboratories of the National Research Council (Italy), during the Type Approval test cycle, at constant speed and under real-world driving cycles. This analytical-experimental investigation was executed with a methodology that improves vehicles emission assessment in comparison with the modeling approaches that are based on fixed legislative driving standards. The statistical processing results so obtained are very useful also in order to improve the database of emission models commonly used for estimating emissions from road transport sector, then they can be used to evaluate the environmental impact of last generation medium-size motorcycles under real driving behaviors.
Due to increasing worldwide trade, transportations of goods through seaports have been gradually ... more Due to increasing worldwide trade, transportations of goods through seaports have been gradually growing in the past years; harbours are main centres of economic activities, with unavoidable consequences on the air quality degradation and human health of many urbanized ports. This study provides a methodology to assess the impact of pollutant emission from marine engines on ambient air quality of the coastal areas. The environmental pollution from sea traffic was evaluated by assessing the production and atmospheric dispersion of exhaust emissions produced by ship engines in manoeuvring mode and in fuel switch conditions from heavy-sulphur residual fuel oil to low-sulphur distillate fuel oil. Specifically, this study analyses the emissive behaviour of merchant ships, equipped with large size diesel engines and transiting in the port of Naples, which is located very close to the densely populated urban centre. The spatial distribution of the air pollutant concentrations was calculated with a specific dispersion modelling approach, delivering significant data about the environmental impact of merchant ship emissions on the coastal urban area. The NOX, PM and SOX pollutant concentrations estimated with this methodology were also compared with pollution levels measured in an experimental monitoring campaign performed in the port of Naples. Estimated concentration levels were lower than measured values because the latter were affected by other anthropogenic emissive sources adjacent to port area, above all exhaust emissions from the road transport sector. Both the calculated and measured concentration levels over coastal area were below the European Limit Values.
Abstract This paper proposes an innovative solar electricity generation system based on the steam... more Abstract This paper proposes an innovative solar electricity generation system based on the steam Rankine cycle, which employs screw expanders and parabolic trough collectors, with water as heat transfer and working fluid. Owing to its good efficiency at low-medium heat source temperatures, the solar generation system can meet the need to design renewable energy power plant with simple technical requirements in heat storage and collection. Screw expander-based solar thermal electricity systems have further advantages: avoidance of overheating, satisfactory applicability in energy conversion with liquid-steam mixtures, low operating pressure and good applicability for distributed power generation. In this paper a thermodynamic mathematical model on the polytropic expansion process is first investigated, revealing variation of isentropic efficiency with the operating pressure ratio and built-in volume ratio of the screw expander. Basic criteria are then provided to evaluate the energetic and exergetic benefits of such a power plant, developing a macro balance to define optimum operating conditions. Water evaporation temperature and condensation pressure were thus optimized with respect to heat-to-power conversion efficiency, solar thermal power generation efficiency and exergetic efficiency. Our results indicate that the optimum evaporation temperature ranges from about 204 °C to 276 °C with increasing solar radiation, whereas the corresponding maximum solar thermal power efficiency and exergetic efficiency are around 12.6% and 17.8%, respectively.
Abstract Ethanol is considered a clean and renewable alternative fuel for SI engines when used in... more Abstract Ethanol is considered a clean and renewable alternative fuel for SI engines when used in blends with gasoline in different fractions to increase oxygen content, thus decreasing exhaust emissions of incomplete combustion products and dependency on fossil fuels. However, the scientific literature on fuel consumption and exhaust emissions of last generation SI engines during cold operating conditions and using ethanol/gasoline blends is far from comprehensive. In this experimental investigation, ethanol obtained from grape pomace was used in fuels prepared by blending it in increasing ratios (10, 20 and 30 vol.%) with oxygen-free gasoline. These ethanol/gasoline blended fuels were used to assess emissions and energy consumption of a motorcycle equipped with a large displacement four–stroke SI engine. Fuel consumption and exhaust emissions were measured during the cold transient over the execution of chassis–dynamometer tests, and calculated as a function of oxygen content of all ethanol/gasoline test fuels. Significant reductions in cold emission factors compared to the commercial gasoline were associated with well–defined percentages of ethanol content in gasoline fuel blends.
Abstract The object of this study is the plan of original power systems of reduced size, investig... more Abstract The object of this study is the plan of original power systems of reduced size, investigating on the energetic benefits of a solar plant with parabolic trough collectors and steam screw expander. Usually, medium temperature solar systems need to be coupled with organic fluids cycles which allow high specific expansion work at low temperature and pressure, so involving a heat exchange between two fluids with the consequent exergetic degradation of the available thermal energy. This paper focuses on the steam screw expander-based solar thermal electricity system with water as heat transfer and storage fluid, clarifying in which operating conditions this simple plant layout could be convenient in terms of energy saving. A mathematical model on the system part-load behaviour is analysed and the optimum working conditions of this solar system were determined, revealing variations of maximum solar thermal power efficiency with operating pressure ratio and beam solar radiation.
Abstract This study analyses the production and the dispersion of air pollutants produced by ship... more Abstract This study analyses the production and the dispersion of air pollutants produced by ship engines of great displacement during the approaching phase to the seaports. In agreement with the present environmental rules, several scenarios were examined, considering the possibility of fuel switch, from heavy fuel oil to marine gasoil. After characterizing the emissions during this fuel change-over, and taking into account the most frequent routes, we analyzed the specific case of the port of Naples. For this case-study we evaluated different scenarios of pollutants dispersion from ships arriving and departing, by using the Gaussian model ISC and considering in particular the effect on the coastal zone adjacent to the port. The results are represented graphically and provide valuable insights about the impact of marine traffic on air quality. Such information may be seen as useful tools for the improvement of maritime legislation on emissions, since emission of air pollutants from ships of large size is a key factor in air quality state in the surrounding areas to ports.
Urban areas in developed countries are characterized by an increasing decline in air quality stat... more Urban areas in developed countries are characterized by an increasing decline in air quality state mainly due to the exhaust emissions from vehicles. Besides, due to catalyst improvements and electronic mixture control of last generation engines, nowadays CO and HC cold start extra-emissions are heavily higher than emissions exhausted in hot conditions, with a clear consequence on air quality of the urban contexts. Ethanol combined with gasoline can be widely used as an alternative fuel due to the benefit of its high octane number and its self-sustaining characteristics. Ethanol, in fact, is well known as potential alcohol alternative fuel for SI engines, since it can be blended with gasoline to increase oxygen content, then decreasing CO and HC emissions and the depletion of fossil fuels.
In this paper, a theoretical/experimental analysis of a new measurement system of the chain stren... more In this paper, a theoretical/experimental analysis of a new measurement system of the chain strength is described. Such system is functional for the control of the electrically assisted bicycles which are characterized by a driving torque due to the contribution of both electric motor and rider. The electrical assistance is commonly regulated taking into account informations such as the chain ring rotation, the bicycle speed and/or the torque given by the rider. As a consequence, suitable measurements have to be made on board in order to handle the assistance performances and to improve drivability.
This study derives from the need to evaluate the impact on the urban air quality of two-wheeler v... more This study derives from the need to evaluate the impact on the urban air quality of two-wheeler vehicular class. Mopeds and motorcycles, in fact, are increasingly used in recent years, representing a great share of motor-powered vehicles in urban environment. This paper is finalized at the examination of the emissions of the last generation motorcycles, contributing broadly to extend knowledge of twowheeler emission behavior, with reference to cold and hot operating conditions. For this aim, an experimental investigation was performed on a medium-size motorcycle belonging to the Euro-3 statutory category, evaluating the exhaust emissions of regulated pollutants. This scooter was tested on a dynamometer bench both on a type approval test cycle and on real-world test cycles in order to study the influence of driving cycles on the emission levels. The statistical processing results of the experimental data were compared with recent emission models for estimating emissions from road tra...
Abstract— The paper describes the development of an electric bicycle mathematical model and its e... more Abstract— The paper describes the development of an electric bicycle mathematical model and its experimental validation. The modelling procedure has focused on the vehicle and the electric motor dynamics. The model has been particularized with respect to an innovative electric bicycle. Preliminary experimental tests have involved the characterization of a novel chain strength sensor and then, different drive conditions have been assigned and the results have been collected in order to carry on the parameter identification. Successively, novel experimental results have been adopted to validate the proposed model. The validation procedure has highlighted the goodness of the adopted approach, allowing to employ the mathematical model for predictive analysis of the electric bicycle performances in simulation environment.
Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide ... more Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to ...
Screw expanders are volumetric machines particularly suitable in energy conversion with steam–liq... more 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 wor...
In the most recent years, renewable sources are becoming increasingly crucial owing to both the s... more In the most recent years, renewable sources are becoming increasingly crucial owing to both the stocks of fossil fuels being depleted and environmental problems around the globe. This study describes the environmental assessment of thermal power plant-based trigeneration systems fuelled by renewable energy sources for district heating/cooling system. First, the paper examines the thermal and refrigeration requests of a possible new urban area with electricity, cooling and heating provided by a new trigeneration power system; this study is performed considering a trigeneration plant based on the internal combustion engines fuelled by renewable vegetable oil. Subsequently, a numerical assessment is achieved in order to evaluate the environmental impact on the neighboring area of the trigeneration system. The results of these numerical simulations show that the impact of this power plant on air quality state is not significant in this area. As a result, this kind of trigeneration power...
Abstract In the latest years the effect of powered two-wheelers on air polluting emissions is gen... more Abstract In the latest years the effect of powered two-wheelers on air polluting emissions is generally noteworthy all over the world, notwithstanding advances in internal combustion engines allowed to reduce considerably both fuel consumption and exhaust emissions of SI engines. Nowadays, in fact, these vehicles represent common means of quotidian moving, serving to meet daily urban transport necessities with a significant environmental impact on air quality. Besides, the emissive behavior of the two-wheelers measured under fixed legislative driving standards (and not on the local driving conditions) might not be sufficiently representative of real world motorcycle riding. The purpose of this investigation is a deeper research on emissive levels of in-use motorcycles equipped with last generation SI engines under real world driving behavior. In order to analyze the effect of vehicle instantaneous speed and acceleration on emissive behavior, instantaneous emissions of CO, HC and NO X were measured in the exhaust of a four-stroke motorcycle, equipped with a three-way catalyst and belonging to the Euro-3 legislative category. Experimental tests were executed on a chassis dynamometer bench in the laboratories of the National Research Council (Italy), during the Type Approval test cycle, at constant speed and under real-world driving cycles. This analytical-experimental investigation was executed with a methodology that improves vehicles emission assessment in comparison with the modeling approaches that are based on fixed legislative driving standards. The statistical processing results so obtained are very useful also in order to improve the database of emission models commonly used for estimating emissions from road transport sector, then they can be used to evaluate the environmental impact of last generation medium-size motorcycles under real driving behaviors.
Due to increasing worldwide trade, transportations of goods through seaports have been gradually ... more Due to increasing worldwide trade, transportations of goods through seaports have been gradually growing in the past years; harbours are main centres of economic activities, with unavoidable consequences on the air quality degradation and human health of many urbanized ports. This study provides a methodology to assess the impact of pollutant emission from marine engines on ambient air quality of the coastal areas. The environmental pollution from sea traffic was evaluated by assessing the production and atmospheric dispersion of exhaust emissions produced by ship engines in manoeuvring mode and in fuel switch conditions from heavy-sulphur residual fuel oil to low-sulphur distillate fuel oil. Specifically, this study analyses the emissive behaviour of merchant ships, equipped with large size diesel engines and transiting in the port of Naples, which is located very close to the densely populated urban centre. The spatial distribution of the air pollutant concentrations was calculated with a specific dispersion modelling approach, delivering significant data about the environmental impact of merchant ship emissions on the coastal urban area. The NOX, PM and SOX pollutant concentrations estimated with this methodology were also compared with pollution levels measured in an experimental monitoring campaign performed in the port of Naples. Estimated concentration levels were lower than measured values because the latter were affected by other anthropogenic emissive sources adjacent to port area, above all exhaust emissions from the road transport sector. Both the calculated and measured concentration levels over coastal area were below the European Limit Values.
Abstract This paper proposes an innovative solar electricity generation system based on the steam... more Abstract This paper proposes an innovative solar electricity generation system based on the steam Rankine cycle, which employs screw expanders and parabolic trough collectors, with water as heat transfer and working fluid. Owing to its good efficiency at low-medium heat source temperatures, the solar generation system can meet the need to design renewable energy power plant with simple technical requirements in heat storage and collection. Screw expander-based solar thermal electricity systems have further advantages: avoidance of overheating, satisfactory applicability in energy conversion with liquid-steam mixtures, low operating pressure and good applicability for distributed power generation. In this paper a thermodynamic mathematical model on the polytropic expansion process is first investigated, revealing variation of isentropic efficiency with the operating pressure ratio and built-in volume ratio of the screw expander. Basic criteria are then provided to evaluate the energetic and exergetic benefits of such a power plant, developing a macro balance to define optimum operating conditions. Water evaporation temperature and condensation pressure were thus optimized with respect to heat-to-power conversion efficiency, solar thermal power generation efficiency and exergetic efficiency. Our results indicate that the optimum evaporation temperature ranges from about 204 °C to 276 °C with increasing solar radiation, whereas the corresponding maximum solar thermal power efficiency and exergetic efficiency are around 12.6% and 17.8%, respectively.
Abstract Ethanol is considered a clean and renewable alternative fuel for SI engines when used in... more Abstract Ethanol is considered a clean and renewable alternative fuel for SI engines when used in blends with gasoline in different fractions to increase oxygen content, thus decreasing exhaust emissions of incomplete combustion products and dependency on fossil fuels. However, the scientific literature on fuel consumption and exhaust emissions of last generation SI engines during cold operating conditions and using ethanol/gasoline blends is far from comprehensive. In this experimental investigation, ethanol obtained from grape pomace was used in fuels prepared by blending it in increasing ratios (10, 20 and 30 vol.%) with oxygen-free gasoline. These ethanol/gasoline blended fuels were used to assess emissions and energy consumption of a motorcycle equipped with a large displacement four–stroke SI engine. Fuel consumption and exhaust emissions were measured during the cold transient over the execution of chassis–dynamometer tests, and calculated as a function of oxygen content of all ethanol/gasoline test fuels. Significant reductions in cold emission factors compared to the commercial gasoline were associated with well–defined percentages of ethanol content in gasoline fuel blends.
Abstract The object of this study is the plan of original power systems of reduced size, investig... more Abstract The object of this study is the plan of original power systems of reduced size, investigating on the energetic benefits of a solar plant with parabolic trough collectors and steam screw expander. Usually, medium temperature solar systems need to be coupled with organic fluids cycles which allow high specific expansion work at low temperature and pressure, so involving a heat exchange between two fluids with the consequent exergetic degradation of the available thermal energy. This paper focuses on the steam screw expander-based solar thermal electricity system with water as heat transfer and storage fluid, clarifying in which operating conditions this simple plant layout could be convenient in terms of energy saving. A mathematical model on the system part-load behaviour is analysed and the optimum working conditions of this solar system were determined, revealing variations of maximum solar thermal power efficiency with operating pressure ratio and beam solar radiation.
Abstract This study analyses the production and the dispersion of air pollutants produced by ship... more Abstract This study analyses the production and the dispersion of air pollutants produced by ship engines of great displacement during the approaching phase to the seaports. In agreement with the present environmental rules, several scenarios were examined, considering the possibility of fuel switch, from heavy fuel oil to marine gasoil. After characterizing the emissions during this fuel change-over, and taking into account the most frequent routes, we analyzed the specific case of the port of Naples. For this case-study we evaluated different scenarios of pollutants dispersion from ships arriving and departing, by using the Gaussian model ISC and considering in particular the effect on the coastal zone adjacent to the port. The results are represented graphically and provide valuable insights about the impact of marine traffic on air quality. Such information may be seen as useful tools for the improvement of maritime legislation on emissions, since emission of air pollutants from ships of large size is a key factor in air quality state in the surrounding areas to ports.
Urban areas in developed countries are characterized by an increasing decline in air quality stat... more Urban areas in developed countries are characterized by an increasing decline in air quality state mainly due to the exhaust emissions from vehicles. Besides, due to catalyst improvements and electronic mixture control of last generation engines, nowadays CO and HC cold start extra-emissions are heavily higher than emissions exhausted in hot conditions, with a clear consequence on air quality of the urban contexts. Ethanol combined with gasoline can be widely used as an alternative fuel due to the benefit of its high octane number and its self-sustaining characteristics. Ethanol, in fact, is well known as potential alcohol alternative fuel for SI engines, since it can be blended with gasoline to increase oxygen content, then decreasing CO and HC emissions and the depletion of fossil fuels.
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