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Journal Article

Real Time Emissive Behaviour of a Bi-Fuel Euro 4 SI Car in Naples Urban Area

2013-09-08
2013-24-0173
An experimental campaign was carried out to evaluate the influence of CNG and gasoline on the exhaust emissions and fuel consumption of a bi-fuel passenger car over on-road tests performed in the city of Naples. The chosen route is very traffic congested during the daytime of experimental measurements. An on-board analyzer was used to measure CO, CO2, NOx tailpipe concentrations and the exhaust flow rate. Throughout a carbon balance on the exhaust pollutants, the fuel consumption was estimated. The exact spatial position was acquired by a GPS which allowed to calculate vehicle speed and the traffic condition was monitored by a video camera. Whole trip realized by the vehicle was subdivided in succession of kinematic sequences and the vehicle emissions and fuel consumption were analyzed and presented as value on each kinematic sequence. Moreover, throughout a multivariate statistical analysis of sequences, the driving cycles characterizing the use of vehicle were identified.
Journal Article

The Evaluation of a New Kinematic Emissions Model on Real and Simulated Driving Cycles

2010-05-05
2010-01-1564
The evaluation of vehicles real emissions circulating in urban areas is a basic activity for planning and management of implemented traffic measures aiming at emission control and air quality improvement. National, region, and city emission inventories require overall average emission estimation based on modeling technique with a few input parameters such as fleet composition and mission profile, represented by average speed. But in the field of emission modeling an important open issue is the very expensive costs of experimental campaigns needed to obtain driving cycle statistically representative of driving behavior, also if only in a specific link of a network. A possible approach to deal with this problem is represented by the use of traffic microscopic simulation models which are capable to simulate individual car motion on the basis of traffic conditions, road characteristics and management rules.
Technical Paper

Real Driving Emissions of a Light-Duty Vehicle in Naples. Influence of Road Grade

2015-09-06
2015-24-2509
The aim of this study is to investigate the parameters influencing the real driving emission monitoring with particular attention towards the influence of road gradient. For this purpose, an experimental activity was carried out with a Euro 5 Diesel light-duty vehicle, driven along two tracks of Naples characterized by a different road gradient: the first pattern is quite flat, the second includes positive (+2.9%) and negative (−3.6%) road gradient. Exhaust emissions of CO, THC, NOx, CO2 were acquired on road by using a portable emission measuring system (PEMS) connected also to the Engine Control Unit for saving the main engine parameters and to the GPS for the geographical coordinates and altitude. The acquired speed profiles were repeated on the chassis-dynamometer without simulating the road gradient.
Technical Paper

Emission Factors Evaluation in the RDE Context by a Multivariate Statistical Approach

2019-09-09
2019-24-0152
The Real Driving Emission (RDE) procedure will measure the pollutants, such as NOx, emitted by cars while driven on the road. RDE will not replace laboratory tests, such as the current WLTP but it will be added to them. RDE is complementary to the laboratory-based procedure to check the pollutant emissions level of a light-duty vehicle in real driving conditions. This means that the car will be driven on a real road according to random acceleration and deceleration patterns conditioned by traffic flow. So, the procedure will ensure that cars deliver real emissions over on-road and so the currently observed differences between emissions measured in the laboratory and those measured on road under real-world conditions, will be reduced. However, the identification of a path on the road to check the test conditions of RDE is not easy and hardly repeatable.
Technical Paper

Vapor and Liquid Phases of the ECN Spray G Impacting on a Flat Wall at Engine-Like Conditions

2016-10-17
2016-01-2199
Mixture formation is fundamental for the development of the combustion process in internal combustion engines, for the energy release, the consumption, and the pollutant formation. Concerning the spark ignition engines, the direct injection technology is being considered as an effective mean to achieve the optimal air-to-fuel ratio distribution at each operating condition, either through charge stratification around the spark plug and stoichiometric mixture under the high power requirements. Due to the highest injection pressures, the impact of a spray on the piston or on the cylinder walls causes the formation of liquid film (wall-film) and secondary atomization of the droplets. The wall-film could have no negligible size, especially where the mixture formation is realized under a wall-guided mode. The present work aims to report the effects of the ambient pressure and wall temperature on the macroscopic parameters of the spray impact on a wall.
Technical Paper

Impinging Jets of Fuel on a Heated Surface: Effects of Wall Temperature and Injection Conditions

2016-04-05
2016-01-0863
In spark ignition engines, the nozzle design, fuel pressure, injection timing, and interaction with the cylinder/piston walls govern the evolution of the fuel spray inside the cylinder before the start of combustion. The fuel droplets, hitting the surface, may rebound or stick forming a film on the wall, or evaporate under the heat exchange effect. The face wetting results in a strong impact on the mixture formation and emission, in particular, on particulate and unburned hydrocarbons. This paper aims to report the effects of the injection pressure and wall temperature on the macroscopic behavior, atomization, and vaporization of impinging sprays on the metal surface. A mono-component fuel, iso-octane, was adopted in the spray-wall studies inside an optically-accessible quiescent vessel by imaging procedures using a Z-shaped schlieren-Mie scattering set-up in combination with a high-speed C-Mos camera.
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