Papers by Maria Vittoria Prati
Emission factors and fuel consumption of CNG buses in real driving conditions
Transportation Research Part D: Transport and Environment
The influence of fuel composition on particulate emissions of di diesel engines
SAE Technical Papers, 1993
Bertoli, C., Del Giacomo, N., Iorio, B., and Prati, M., "The Influence of Fuel Compo... more Bertoli, C., Del Giacomo, N., Iorio, B., and Prati, M., "The Influence of Fuel Composition on Particulate Emissions of DI Diesel Engines," SAE Technical Paper 932733 , 1993, doi:10.4271/932733. ... The effect of different fuel parameters on emissions is difficult to understand, the response depending upon different engine technologies. In addition the isolation of some of the fuel variables is often very hard. ... The present paper discusses the main results obtained testing a matrix of 14 fuels designed for obtain large variations of cetane number, sulphur and aromatic ...
Monitoraggio della qualità dell’aria in una zona influenzata dall’attività di un cementificio mediante analisi di foglie di leccio e di olivo
XX Congresso S.It.E, 2010
Journal of Aerosol Science, 2020
Take-down policy If you believe that this document breaches copyright please contact us providing... more Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Scientific Reports
A small-scale plant was built for measuring the ability of solid sorbents towards the capture of ... more A small-scale plant was built for measuring the ability of solid sorbents towards the capture of carbon dioxide (CO2) in exhaust flue gas from an internal combustion engine. The investigated sorbents were calcium and lithium hydroxides. Both sorbents are low cost and used in the breathing gas purification systems. The carbonation capacity of each sorbent was measured for different sorbent granulometry (pellets and powder), different temperature (from ambient up to 300 °C), gas space velocity, moisture content and chemical composition of the gaseous stream. The aim was, in fact, to expose the sorbents to a gas stream with chemical and physical parameters close to those at the exhaust of an internal combustion engine. Carbonation capacity was measured with a double technique: on-line by continuously CO2 measurement with a non-dispersive infrared analyzer and off-line by using scanning electron microscopy on carbonated sorbents. Experimental results showed good CO2 uptake capacity of c...
Energies, 2020
The valorization of residual biomass plays today a decisive role in the concept of “circular econ... more The valorization of residual biomass plays today a decisive role in the concept of “circular economy”, according to which each waste material must be reused to its maximum extent. The collection and energy valorization at the local level of biomass from forest management practices and wildfire prevention cutting can be settled in protected areas to contribute to local decarbonization, by removing power generation from fossil fuels. Despite the evident advantages of bioenergy systems, several problems still hinder their diffusion, such as the need to assure their reliability by extending the operating range with materials of different origin. The Italian project “INNOVARE—Innovative plants for distributed poly-generation by residual biomass”, funded by the Italian Ministry of Economic Development (MISE), has the main scope of improving micro-cogeneration technologies fueled by biomass. A micro-combined heat and power (mCHP) unit was chosen as a case study to discuss pros and cons of ...
Catalytic Conversion of CO2 to CH4 with a Ru Catalyst: Application at Vehicle Exhaust
Emission Control Science and Technology, 2017
For the first time, catalytic conversion of CO2 to CH4 (Sabatier reaction) has been studied on re... more For the first time, catalytic conversion of CO2 to CH4 (Sabatier reaction) has been studied on real vehicle exhaust. Preliminary tests were carried out on model gas mixtures using as reactants a N2/CO2 gas mixture (CO2 = 9.5 vol% concentration similar to that of road vehicle exhaust) and pure hydrogen. Ruthenium powder (5 wt%) on alumina was used as catalyst, in a fixed bed cylindrical reactor. The operating conditions investigated are P = 1 atm, temperature in the range 160–320 °C, contact time 0.6–1.29 s, and H2/CO2 ratio 2.75–4.11. Experimental conditions were varied to study the effect of temperature, contact time, and H2/CO2 ratio on conversion, yield, and selectivity of the process. Once evaluated the performance of the catalytic process and identified the best operating conditions, real exhausts of a two-wheel motorcycle and a four-wheel gasoline vehicle were treated with the same experimental apparatus. Analyses of physical and chemical characterization of catalyst samples before and after the use were also performed. Results show that, even though best performances are generally obtained with model mixtures, high CO2 conversion together with high yield and selectivity in CH4 can be obtained with real vehicle exhausts too. Moreover, phenomena causing the deactivation of catalyst have not been observed. Results seem to indicate good opportunities for the development of the process.
Journal of Catalysis, 2015
A marine engine pollution abatement system was constructed and tested on a 1.5 MW auxiliary marin... more A marine engine pollution abatement system was constructed and tested on a 1.5 MW auxiliary marine engine. The integrated system, designed to abate all of the currently legislated emissions from marine engines, consisted of a monolithic Pt/Al 2 O 3 oxidation catalyst and a seawater scrubber, both of suitable dimensions for the engine size. The test results obtained showed the general validity of the approach adopted, as significant abatement of emissions was achieved. However, under the conditions used, the system showed some limitations with regard to the sulphur content of the fuel. On the basis of the results obtained, the system can be used with fuel sulphur content of up to 0.4%, while problems were encountered when a fuel with a sulphur content of 2.0% was used. Whereas the catalytic section operated satisfactorily, fine tuning of the scrubber operating conditions is necessary to improve abatement of NO x and increase the range of fuel sulphur which can be used with the system.
SAE Technical Papers, 1992
Резюме. Статья посвящена лечению тяжелой врожденной патологии-артрогрипозу. Представлены общие ... more Резюме. Статья посвящена лечению тяжелой врожденной патологии-артрогрипозу. Представлены общие сведения о данной патологии и причинах возникновения, а также развитие системы оказания помощи больным с артрогрипозом в Институте им. Г. И. Турнера. Подробно описаны варианты деформаций верхних и нижних конечностей, а также методики комплексного лечения детей первого года жизни в зависимости от характера и степени тяжести патологии. Ключевые слова: артрогрипоз, контрактуры суставов, лечение.
International Symposium COMODIA, 1990
The effect of the air/fuel ratio on the carbon and hydrocarbon distribution inside a direct injec... more The effect of the air/fuel ratio on the carbon and hydrocarbon distribution inside a direct injection diesel engine has been studied by means of fast sampling and chemical analysis of the combustion products collected during the combustion cycle in a given location of a single cylinder diesel engine burning tetradecane.
Environmental Science and Pollution Research, 2013
For the first time until now, the results from a prediction model (Atmospheric Dispersion Modelli... more For the first time until now, the results from a prediction model (Atmospheric Dispersion Modelling System (ADMS)-Road) of pollutant dispersion in a street canyon were compared to the results obtained from biomonitors. In particular, the instrumental monitoring of particulate matter (PM10) and the biomonitoring of 14 polycyclic aromatic hydrocarbons (PAHs) and 11 metals by Quercus ilex leaves and Hypnum cupressiforme moss bags, acting as longand short-term accumulators, respectively, were carried out. For both PAHs and metals, similar bioaccumulation trends were observed, with higher concentrations in biomonitors exposed at the leeward canyon side, affected by primary air vortex. The major pollutant accumulation at the leeward side was also predicted by the ADMS-Road model, on the basis of the prevailing wind direction that determines different exposure of the street canyon sides to pollutants emitted by vehicular traffic. A clear vertical (3, 6 and 9 m) distribution gradient of pollutants was not observed, so that both the model and biomonitoring results suggested that local air turbulences in the street canyon could contribute to uniform pollutant distribution at different heights.
Transportation Engineering, 2021
In the next years, the number of circulating plug-in hybrid electric vehicles was expected to inc... more In the next years, the number of circulating plug-in hybrid electric vehicles was expected to increase worldwide. Hybrid electric/gasoline powertrain is considered a promising solution to meet the future goals of greenhouse gas emission reduction by road transport sector. This paper investigates the emissive and energetic behaviour of a plug-in hybrid electric passenger car over on road testing. Measurements of CO, CO 2 , NO x exhaust emissions and of main electric motor parameters were carried out by using portable emission measurement system over urban, rural and motorway routes in Naples (Italy). Routes were selected for complying with European Real Driving Emission (RDE) legislation. Moreover, an additional urban route, characterised by strong road grade and non-RDE compliant, was investigated. RDE test allowed to assess the influence of the battery state of charge, hybrid mode (charge sustaining and charge depleting), road grade and vehicle air conditioning on the exhaust emission and energy consumption. An overall advantage of charged battery and charge depleting mode was observed in terms of CO 2 emissions and fuel consumption. CO and NO x emissions are strongly influenced by driving when the vehicle's internal combustion engine starts. When it occurs in motorway patterns, CO and NO x peak emissions are observed at tailpipe. Pure electric driving, with consequent zero emissions, are guaranteed over urban strong uphill when battery is full charged.
Improving the NOx reduction performance of an Euro VI d SCR System in real-world condition via nonlinear model predictive control
International Journal of Engine Research, 2021
This paper deals with the possibility of improving the urea dosage control for the Selective Cata... more This paper deals with the possibility of improving the urea dosage control for the Selective Catalytic Reduction Systems (SCR) of an Euro VI d diesel light commercial vehicle in order to increase [Formula: see text] after-treatment reduction performance. To this aim, first, we assess the effective emissions abatement performance for the appraised diesel vehicle via real-world experimental campaign, carried out according to the Real Driving Emissions (RDE) tests on urban, extra-urban and motorway road sections in Naples, Italy. Based on these real-world data, we derive a parameterized control-oriented model for the SCR system which is, then, exploited for the designing of an alternative urea injection logic which could be able to maximize the [Formula: see text] reduction efficiency while minimizing tailpipe ammonia slip. Specifically, the optimal AdBlue injection rate is designed according to a Nonlinear Model Predictive Control Approach which allows obtaining a proper trade-off bet...
Idling Vehicle Emissions and Fuel Consumption in Urban Use: Influence of the Stop Technology
2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018
Engine idle stop-start (S&S) is a technology which allows a vehicle to automatically turn off... more Engine idle stop-start (S&S) is a technology which allows a vehicle to automatically turn off the internal combustion engine (ICE) when the vehicle has a rest and restarts the ICE when the driver applies pressure to the accelerator or releases the brake. Stop-Start system originated in Europe to save fuel during the type-approval New European Driving cycle (NEDC) because almost 25% of its driving time is in idling conditions. In real use, the largest benefits of S&S systems in vehicles result in urban areas where frequent stops are common. To evaluate the benefits of such systems in terms of fuel saving and emission reduction, an experimental campaign has been realized in Napoli. Three cars have been instrumented by using a Portable Emission System (PEMS) and driven along urban routes. Carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxides (NOX) have been evaluated for each trip in function of the average time spent stopping at traffic lights or for traffic conditions, as a percentage of a trip's duration.
Multi-objective optimization of a syngas powered reciprocating engine equipping a combined heat and power unit
Applied Energy, 2020
Abstract Syngas deriving from biomass gasification is receiving increased interest as an alternat... more Abstract Syngas deriving from biomass gasification is receiving increased interest as an alternative fuel in spark ignition (SI) engines for power generation, despite problems related to the variability of its composition and the low energy density. Syngas release from gasifiers is indeed strongly affected by the quality of the feedstock and by the specific features and control strategy of the reactor. The paper considers the possibility to achieve, at the same time, high efficiency and low pollutant emissions of a syngas powered engine by acting on operating variables as the spark timing and the air-to-fuel ratio, with also the possible inclusion of exhaust gas recirculation (EGR). Model-based design and multi-objective optimization methods are applied as a feasible approach to address this issue, hence to improve the energetic and the environmental performances of power generation under a flexible fuel quality. A one-dimensional (1D) model of a naturally aspirated SI engine fuelled by syngas, properly developed and validated through a specific experimental campaign, is here presented to investigate the effect of the main controlling variables on power output and emissions. A proper design of experiment (DoE) space is considered. The 1D model is coupled with a genetic optimization algorithm for the search of the best compromise solution between maximum performance and minimum pollutants amount. The identified optimal solution allows a reduction up to the 50% for both nitrogen oxides and carbon monoxide emissions with a negligible worsening of the power output.
Assessment of Euro 5 diesel vehicle NOx emissions by laboratory and track testing
Environmental Science and Pollution Research, 2019
The Volkswagen scandal has promoted experimental campaigns worldwide aimed to assess the real exh... more The Volkswagen scandal has promoted experimental campaigns worldwide aimed to assess the real exhaust emissions of in-use vehicles. Attention has been paid to diesel vehicle NOx emissions that are much higher than legislative type-approval limits. This paper analysed exhaust emissions of a fleet of ten Euro 5 diesel vehicles. NOx emissions were measured during laboratory and track testing. In both cases, the type-approval test was carried out with cold and warm starts. Moreover, in the laboratory, a modified type-approval test and a real urban driving cycle were executed in order to characterise emissions in multiple operating conditions, outside of the homologation boundaries. The testing environment did not influence the emissions behaviour of the tested vehicles. Track and laboratory results, in fact, were comparable when ambient conditions were comparable. The parameter which played the main role in terms of NOx emissions is the ambient temperature, fixed at 23 °C in laboratory and not controlled on the track. Above 28 °C, NOx emissions were much higher than the approval limit (almost 600 mg/km). Moreover, warm driving cycles always introduced higher NOx emissions than cold ones, because of the partial use and/or deactivation of the EGR circuit (one of effective measures to reduce NOx formation). The ratio between warm and cold emissions ranged from 2 to 5. The engine parameter which helped explain the relationship between NOx emissions and thermal engine status was the intake air temperature. For intake air temperatures below 40 °C, NOx emissions were lower than 0.2 g/km. Above 40 °C, they suddenly increased up to almost 0.6 g/km. Another issue highlighted by the experimental results was that dynamic real driving caused the highest NOx emissions (almost 1 g/km).
Statistical evaluation of slope's effect on real emissions and fuel consumption performed with different cars in Naples urban area
In the field of sustainable mobility emissions values are still remarkable, especially in urban a... more In the field of sustainable mobility emissions values are still remarkable, especially in urban areas, where more than one-half of the world's population now lives. To give a contribution to this issue a research activity was realized within a national scientific project. In this context it was realized the evaluation of the fuel consumption and emissions during the actual use of the vehicle on the road. Tests were carried out with different cars, in order to identify and to describe the most representative road paths of the city of Naples where topography presents significant changes in slope. The emissions and fuel consumption were analyzed according to the shape of the vehicle, the traffic information, the definition of the driving cycles and the characteristics of the path, integrated with the data available through the free cartographies. A particular attention was given to the slope variability along the streets during each journey performed by the instrumented vehicle. Finally the slope analysis can be correlated to the emission and consumption values in a specific road position, and it could be evaluated its influence on their behaviour.
Journal of the Air and Waste Management Association, 2009
To improve the accuracy, reliability, and representativeness of emission factors, 10 European lab... more To improve the accuracy, reliability, and representativeness of emission factors, 10 European laboratories worked together to study the influence of 20 parameters on the measurement of light-vehicle emission factors on chassis dynamometer of 4 main categories: driving patterns, vehiclerelated parameters, vehicle sampling, and laboratory-related parameters. The results are based on (1) literature synthesis, (2) approximately 2700 specific tests with 183 vehicles, and (3) the reprocessing of more than 900 tests. These tests concern the regulated atmospheric pollutants and pre-Euro to Euro 4 vehicles. Of the 20 parameters analyzed, 7 seemed to have no effect, 7 were qualitatively influential, and 6 were highly influential (gearshift strategy, vehicle mileage, ambient temperature, humidity, dilution ratio, and driving cycle). The first four of the six were able to have correction factors developed for them. The results IMPLICATIONS The accuracy of most air pollution modeling and the efficiency of emission standard reinforcement depend on the accuracy of emission factor measurements. The understanding of the role of various emission parameters allows for the improvement of the standard emission measurement method and the quality of the emission calculations at the local, regional, or national levels.
Does European Type approval procedure encourage the diffusion of hybrid and other low emission vehicles?
SAE Technical Papers, 2010
Abstract: European Type approval procedure defines a synthetic driving cycle (the NEDC) over whic... more Abstract: European Type approval procedure defines a synthetic driving cycle (the NEDC) over which one vehicle per type has to be tested. Euro 1, 2, 3, 4 and 5 differ (beside vehicle preconditioning and warm-up procedures introduced since Euro 3) only because limits for the different pollutants have been progressively lowered.
Emissions and Combustion Behavior of a Bi-Fuel Gasoline and Natural Gas Spark Ignition Engine
SAE International Journal of Fuels and Lubricants, 2011
Abstract In the last ten years, the number of natural gas vehicles worldwide has grown rapidly wi... more Abstract In the last ten years, the number of natural gas vehicles worldwide has grown rapidly with the biggest contribution coming from the Asia-Pacific and Latin America regions. As natural gas is the cleanest fossil fuel, the exhaust emissions from natural gas spark ignition vehicles are lower than those of gasoline powered vehicles. Moreover, natural gas is less affected by price fluctuations and its resources are more evenly widespread over the globe than to oil. However, as natural gas vehicles are usually bi-fuel gasoline and natural ...
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Papers by Maria Vittoria Prati