ANALYSIS OF MEASUREMENT ERRORS OF CVS METHOD USED FOR TESTS OF POLLUTANT EMISSIONS FROM LIGHT-DUTY VEHICLES

In order to curb pollutant emissions from light-duty vehicles in the European Union, a set of complex regulations have been ap-proved in the recent years (2016-2018) including more stringent emissions tests, independent in-service conformity checks, and a novel type-approval framework which includes market surveillance provisions to complement the type-approval requirements. Tailpipe emissions will need to meet stringent emission limits before entering the market at type-approval and at the end of the production line, as well as during their normal life under normal conditions of use. This contribution aims at providing a comprehensive but synthetic analysis of the current regulatory context in the EU.

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Air pollutant emissions of light-duty vehicles operating on various natural gas compositions

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2011.08.005 ◽

2012 ◽

Vol 4 ◽

pp. 8-16 ◽

Cited By ~ 41

Author(s):

Georgios Karavalakis ◽

Thomas D. Durbin ◽

Mark Villela ◽

J. Wayne Miller

Keyword(s):

Natural Gas ◽

Air Pollutant ◽

Pollutant Emissions ◽

Light Duty ◽

Light Duty Vehicles

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Variation of the Distribution of Atmospheric n-Alkanes Emitted by Different Fuels’ Combustion

Atmosphere ◽

10.3390/atmos11060643 ◽

2020 ◽

Vol 11 (6) ◽

pp. 643

Author(s):

Sofia Caumo ◽

Roy E. Bruns ◽

Pérola C. Vasconcellos

Keyword(s):

Particulate Matter ◽

Principal Component ◽

Air Pollutant ◽

Atmospheric Particulate Matter ◽

Pollutant Emissions ◽

Anthropogenic Sources ◽

Heavy Vehicles ◽

Light Duty ◽

Principal Factors ◽

Light Duty Vehicles

This study presents the emission profiles of n-alkanes for different vehicular sources in two Brazilian cities. Atmospheric particulate matter was collected in São Paulo (Southeast) and in Salvador (Northeast) to determine n-alkanes. The sites were impacted by bus emissions and heavy and light-duty vehicles. The objective of the present study is to attempt to differentiate the profile of n-alkane emissions for particulate matter (PM) collected at different sites. PM concentrations ranged between 73 and 488 µg m−3, and the highest concentration corresponded to a tunnel for light and heavy duty vehicles. At sites where diesel-fueled vehicles are dominant, the n-alkanes show a unimodal distribution, which is different from the bimodal profile observed in the literature. Carbon preference index values corresponded to anthropogenic sources for most of the sites, as expected, but Cmax varied comparing to literature and a source signature was difficult to observe. The main sources to air pollution were indicated by principal component analysis (PCA). For PCA, a receptor model often used as an exploratory tool to identify the major sources of air pollutant emissions, the principal factors were attributed to mixed sources and to bus emissions. Chromatograms of four specific samples showed distinct profiles of unresolved complex mixtures (UCM), indicating different contributions of contamination from petroleum or fossil fuel residues, which are unable to resolve by gas chromatography. The UCM area seemed higher in samples collected at sites with the abundance of heavy vehicles.

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Road vehicles - Supplementary grip devices for tyres of passenger cars and light duty vehicles

10.3403/bsen16662 ◽

2020 ◽

Keyword(s):

Road Vehicles ◽

Passenger Cars ◽

Light Duty ◽

Light Duty Vehicles

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Monte Carlo Simulation Methodology to Assess the Impact of Ambient Wind on Emissions from a Light-Commercial Vehicle Running on the Worldwide-Harmonized Light-Duty Vehicles Test Cycle (WLTC)

Energies ◽

10.3390/en14030661 ◽

2021 ◽

Vol 14 (3) ◽

pp. 661

Author(s):

Alexandros T. Zachiotis ◽

Evangelos G. Giakoumis

Keyword(s):

Monte Carlo Simulation ◽

Energy Consumption ◽

Commercial Vehicle ◽

Ambient Wind ◽

Simulation Methodology ◽

Road Load ◽

Light Duty ◽

Light Commercial Vehicle ◽

Light Duty Vehicles ◽

The Impact

A Monte Carlo simulation methodology is suggested in order to assess the impact of ambient wind on a vehicle’s performance and emissions. A large number of random wind profiles is generated by implementing the Weibull and uniform statistical distributions for wind speed and direction, respectively. Wind speed data are drawn from eight cities across Europe. The vehicle considered is a diesel-powered, turbocharged, light-commercial vehicle and the baseline trip is the worldwide harmonized light-duty vehicles WLTC cycle. A detailed engine-mapping approach is used as the basis for the results, complemented with experimentally derived correction coefficients to account for engine transients. The properties of interest are (engine-out) NO and soot emissions, as well as fuel and energy consumption and CO2 emissions. Results from this study show that there is an aggregate increase in all properties, vis-à-vis the reference case (i.e., zero wind), if ambient wind is to be accounted for in road load calculation. Mean wind speeds for the different sites examined range from 14.6 km/h to 24.2 km/h. The average increase in the properties studied, across all sites, ranges from 0.22% up to 2.52% depending on the trip and the property (CO2, soot, NO, energy consumption) examined. Based on individual trip assessment, it was found that especially at high vehicle speeds where wind drag becomes the major road load force, CO2 emissions may increase by 28%, NO emissions by 22%, and soot emissions by 13% in the presence of strong headwinds. Moreover, it is demonstrated that the adverse effect of headwinds far exceeds the positive effect of tailwinds, thus explaining the overall increase in fuel/energy consumption as well as emissions, while also highlighting the shortcomings of the current certification procedure, which neglects ambient wind effects.

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CFD Study and Experimental Validation of a Dual Fuel Engine: Effect of Engine Speed

Energies ◽

10.3390/en14144307 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4307

Author(s):

Roberta De Robbio ◽

Maria Cristina Cameretti ◽

Ezio Mancaruso ◽

Raffaele Tuccillo ◽

Bianca Maria Vaglieco

Keyword(s):

Natural Gas ◽

High Performance ◽

Engine Speed ◽

Pollutant Emissions ◽

Dual Fuel ◽

Automotive Market ◽

Light Duty ◽

Viable Solution ◽

Dual Fuel Engines ◽

Gas Ratio

Dual fuel engines induce benefits in terms of pollutant emissions of PM and NOx together with carbon dioxide reduction and being powered by natural gas (mainly methane) characterized by a low C/H ratio. Therefore, using natural gas (NG) in diesel engines can be a viable solution to reevaluate this type of engine and to prevent its disappearance from the automotive market, as it is a well-established technology in both energy and transportation fields. It is characterized by high performance and reliability. Nevertheless, further improvements are needed in terms of the optimization of combustion development, a more efficient oxidation, and a more efficient exploitation of gaseous fuel energy. To this aim, in this work, a CFD numerical methodology is described to simulate the processes that characterize combustion in a light-duty diesel engine in dual fuel mode by analyzing the effects of the changes in engine speed on the interaction between fluid-dynamics and chemistry as well as when the diesel/natural gas ratio changes at constant injected diesel amount. With the aid of experimental data obtained at the engine test bench on an optically accessible research engine, models of a 3D code, i.e., KIVA-3V, were validated. The ability to view images of OH distribution inside the cylinder allowed us to better model the complex combustion phenomenon of two fuels with very different burning characteristics. The numerical results also defined the importance of this free radical that characterizes the areas with the greatest combustion activity.

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Chemical characterization of PM2.5 emitted from China IV and China V light-duty vehicles in China

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.147101 ◽

2021 ◽

Vol 783 ◽

pp. 147101

Author(s):

Yanzhao Hao ◽

Shunxi Deng ◽

Zhaowen Qiu ◽

Zhenzhen Lu ◽

Hui Song ◽

...

Keyword(s):

Chemical Characterization ◽

Light Duty ◽

Light Duty Vehicles

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Revised Method for Calculating Departure Sight Distance at Two-Way Stop-Controlled (TWSC) Intersections

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211031544 ◽

2021 ◽

pp. 036119812110315

Author(s):

Essam Dabbour ◽

Said M. Easa

Keyword(s):

Traffic Safety ◽

Major Road ◽

Light Duty ◽

Sight Distance ◽

Data Loggers ◽

Global Positioning ◽

Actual Field ◽

System Data ◽

Negative Impacts ◽

Light Duty Vehicles

This paper introduces realistic acceleration profiles for light-duty vehicles departing from rest at two-way stop-controlled (TWSC) intersections where minor roads (controlled by stop signs) intersect with uncontrolled major roads. The new profiles are based on current vehicle characteristics and driver behavior patterns. They are established based on actual field data collected using global positioning system data loggers that recorded the positional and speed data of various experimental vehicles starting from rest at TWSC intersections. Acceleration profiles are established in this paper and are used to develop a revised method for calculating the departure sight distance at TWSC intersections. Design tables were created to provide realistic sight distance values at TWSC intersections for different design speeds and number of lanes on the major road. It was found that the current values of intersection sight distance suggested by the design guides may be inadequate. Such values may force some approaching drivers on the major road to reduce their speeds or move to different traffic lanes to avoid conflicting with the departing vehicles. These maneuvers may have negative impacts on traffic safety. Therefore, implementing the revised method for calculating intersection sight distance, as presented in this paper, may ultimately reduce traffic collisions at TWSC intersections.

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