Air Pollution and Air Quality State in an Italian National Interest Priority Site. Part 2: The Pollutant Dispersion

Abstract In 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 second paper represents an analysis 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". The contribution of this second paper to the above-mentioned LIFE project consists in the appraisal of the air quality state in this NIPS area, estimating the pollutant concentrations of the main air pollutants (CO, VOC, NO X and PM 10 ) in the area under investigation due to the principal industrial systems (namely punctual sources) and to the main diffused sources. All entropic activities which determine emissions in the atmosphere, in fact, depending on the distance from the areas under examination, could contribute to the soil qualification. The assessment of the air quality to local scale was carried by integrating the data of emission inventory in the NIPS area, that was estimated and reported in the first paper (Part 1), with elaborations of a Gaussian dispersion model

Cold Start Emissions of a Motorcycle Using Ethanol-gasoline Blended Fuels☆

Abstract The object of this study is to investigate the effect of ethanol–gasoline blends on CO and HC cold start emissions from a four- stroke motorcycle. Nowadays, due to catalyst improvements and efficient electronic mixture control, a significant part of the total emissions during a trip takes place during the cold phase. The employ of alternative fuels could be one of means to lessen the cold-start emissions from two-wheeler engines: 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 CO and HC emissions. From this considerations, an experimental-analytical investigation was performed on the exhaust cold extra emissions of one motorcycle belonging to the Euro-3 legislative category. The study explains a calculation procedure to model the cold start transient behavior of motorcycles in order to evaluate the impact of ethanol addition (10, 20 and 30 vol.%) on cold start emissions compared with a reference commercial gasoline. Results of the tests indicate that CO and HC cold start extra emissions by using ethanol–gasoline blended fuels decrease compared to the use of unleaded gasoline. Emission factors during the cold start transient were quantized as a function of the ethanol percentage in the blended fuels

Simulation of engagement control in automotive dry-clutch and temperature field analysis through finite element model

The tribological contact under sliding condition in the clutch facing surfaces during the engagement manoeuvre is strongly affected by heat transfer occurring in the system. The frictional forces acting on the contact surfaces produce mechanical energy losses which are converted in heat with ensuing temperature increase. Reports about the temperature rise after repeated clutch engagements prove the occurrence of interface temperature peaks as high as 300 °C. Unfortunately, only few papers address their focus towards experiments and their outcomes about the influence of temperature and the other operating parameters on the frictional behaviour of the clutch facing materials. In this paper, the Authors mainly explored the frictional behaviour modification for thermal level higher than 250–300 °C, whose effect is a sharp decline of the friction coefficient related to the decomposition of the phenol resin of the facings. Moreover, this phenomenon induces not expected transition from dry friction to mixed dry-lubricated friction which explains the reasons of the friction coefficient drop. The temperature affects also the cushion spring load-deflection characteristic and the ensuing transmitted clutch torque. Thus, an original frictional map has been implemented in a control algorithm to estimate the heat flux during vehicle launch and up-shift manoeuvres. The results of the longitudinal vehicle dynamics has been used in a FEA to predict the temperature field during repeated clutch engagement on the contact surfaces. The simulation results prove that during each engagement the interface temperature increases of 30–35 °C. This means that after only few repeated clutch engagements the temperature field could reach values near the critical point of 300 °C. In such a way, this paper aims at providing useful references to control engineers in order to improve the dry-clutch transmissions performances

Air Pollution and Air Quality State in an Italian National Interest Priority Site. Part 1: The emission Inventory

Abstract In 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

Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

This paper presents the application of an improved Yasutomi correlation for lubricant viscosity at high pressure in a Newtonian elastohydrodynamic line contact simulation. According to recent experimental studies using high pressure viscometers, the Yasutomi pressure-viscosity relationship derived from the free-volume model closely represents the real lubricant piezoviscous behavior for the high pressure typically encountered in elastohydrodynamic applications. However, the original Yasutomi correlation suffers from the appearance of a zero in the function describing the pressure dependence of the relative free volume thermal expansivity. In order to overcome this drawback, a new formulation of the Yasutomi relation was recently developed by Bair et al. This new function removes these concerns and provides improved precision without the need for an equation of state. Numerical simulations have been performed using the improved Yasutomi model to predict the lubricant pressure-viscosity, the pressure distribution, and the film thickness behavior in a Newtonian EHL simulation of a squalane-lubricated line contact. This work also shows that this model yields a higher viscosity at the low-pressure area, which results in a larger central film thickness compared with the previous piezoviscous relations

diagnostic process by using vibrational sensors for monitoring cavitation phenomena in a getoror pump used for automotive applications

Abstract A full experimental investigation on a Gerotor pump used for the lubrication of engines is described in this paper. These pumps, as well known, are widely used on engines for all hydraulic circuits and, for this reason, often they work in some conditions (such as at high speeds and pressure value) which are very challenging. In this paper one of the most unwanted phenomena that often occurs during the pump operation has been investigated: the cavitation. The cavitation can be triggered by many multiple factors such as the sloshing in the tank (translational and rotational motions), high percentage of gas dissolved in the fluid and pressure too low at the pump suction port. Therefore, the characterization of a Gerotor pump in cavitation condition is really interesting. In order to replay the cavitating conditions a pump has been installed on a dedicated test bench of the Department of Industrial Engineering of the university of Naples "Federico II". The pump has been forced to cavitate by placing calibrated orifices on the suction side of the pump. Many decreasing diameters have been located in an aluminum connection block, to measure all the working parameters like the flow-rate, pressure (at the suction and delivery ports), pump speeds and pressure ripple. Cavitating and no-cavitating conditions have been investigated by using an accelerometer sensor in proximity of the pump suction chamber with the aim of monitoring the phenomena in terms of vibration amplitude. As afore mentioned, the pump under investigation has been studied in all operative conditions with and without cavitation phenomena by using a non-intrusive sensor like accelerometer in order to monitoring if cavitation is present. More precisely, the accelerometer sensor has been located close to the pump suction chamber and the vibrations have been acquired contemporarily with pressure signals (intake and outgoing discharge) and properly triggered with tachometer signal by using a multichannel acquisition system (Siemens™). A spectral vibration analysis has been used as diagnostic tool for accurately detecting pump degradation. The results coming from the analysis have shown that in presence of cavitation phenomena the non-intrusive monitoring technique represent a good diagnostic method for assessing pump operability

A Numerical Analysis of an Innovative Flow Ripple Reduction Method for External Gear Pumps

In this paper, an innovative solution to minimize noise emission, acting on the flow ripple, in a prototype External Gear Pump (EGP) is presented. Firstly, a new tool capable to completely simulate this pump’s typologies, called EgeMATor, is presented; the hydraulic model, adopted for the simulation, is based on a lumped parameter method using a control volume approach. Starting from the pump drawing, thanks to different subroutines developed in different environments interconnected, it is possible to analyze an EGP. Results have been compared with the outputs of a three-dimensional CFD numerical model built up using a commercial code, already used with success by the authors. In the second section, an innovative solution to reduce the flow ripple is implemented. This technology is called Alternative Capacitive Volumes (ACV) and works by controlling and uniformizing the reverse flow, performing a consistent reduction of flow non-uniformity amplitude. In particular, a high reduction of the flow non-uniformity is notable in the frequency domain on the second fundamental frequency. The technology is easy to accommodate in a pump housing, especially for high-pressure components, and it helps with reducing the fluid-borne noise

A Critical Analysis on the Lubrication Circuit of a Non-road Diesel Engine by Adopting a 3D and 1D Approaches

AbstractThe aim if this paper is the analysis of a lubrication circuit adopting two simulation models to study the influence of three different lubrication oils.First, the oils pump performance were analyzed with a tri-dimensional simulation model, realized with the commercial code PumpLinx®, which allowed to obtain the performance curves of the oil pump, varying the oils. Then the lubrication circuit was studied with a 1D model, realized with the commercial code LMS AMESim®, and the behaviour of the lubrication circuit was analyzed in terms of pressure drops and components oil consumption.The adopted oils were: 0W30; 5W40 and10W60. In previous activities, both models showed good correlation with experimental data.Analyzing the models results, it was noted that the pressure behavior in the lubrication circuit is highly influenced by the oil, especially for low engine speed and high temperatures.The adopted methodology, that couples mono-dimensional and tri-dimensional models, allowed to analyze the oil influence in a lubrication circuit, avoiding excessive computational cost, but with an acceptable accurac

Electric Motor and Dry Clutch Control in Launch Manoeuvres of Mild-Hybrid Vehicles Based on AMT/DCT Transmissions

Mild-Hybrid Electric Vehicles (mild-HEVs) earned market share over the last years an as effective roadmap to limit air pollution in big cities. In addition to this role, hybrid propulsion can be used to avoid dry clutch overheating in mild-HEVs equipped with automated manual transmissions. Indeed, high thermal level could result in serious damaging of dry clutch linings with very fast decay of expected lifespan affecting vehicle reliability. This paper shows results of vehicle launch simulations to highlight how the propulsion due to electric motor can effectively reduce clutch thermal stress during the slipping phase

3D CFD Transient Analysis of the Forces Acting on the Spool of a Directional Valve

Abstract In this paper, a study of a hydraulic directional valve using a tridimensional fluid-dynamic approach will be shown. During the valve spool displacement, the fluid-dynamics inside the valve creates forces who could reduce the valve performance. The adopted methodology allowed the valve designer to study the complex fluid-dynamic behavior inside the valve and greatly help them to design the internal geometry with the objective of improving the valve performance. This paper shows how a tridimensional fluid-dynamic approach can help engineers to develop the best valve geometry reducing the prototyping requirement and finally the time-to-market and, consequently, the development cost