scholarly journals Gaseous Emissions from Light-Duty Vehicles: Moving from NEDC to the New WLTP Test Procedure

2015 ◽  
Vol 49 (14) ◽  
pp. 8315-8322 ◽  
Author(s):  
Alessandro Marotta ◽  
Jelica Pavlovic ◽  
Biagio Ciuffo ◽  
Simone Serra ◽  
Georgios Fontaras
Keyword(s):  
Test Procedure ◽  
Gaseous Emissions ◽  
Light Duty ◽  
Light Duty Vehicles

Measurement and Evaluation of Real-World Speed and Acceleration Activity Envelopes for Light-Duty Vehicles

2015 ◽  
Vol 2503 (1) ◽  
pp. 128-136 ◽  
Author(s):  
Bin Liu ◽  
H. Christopher Frey
Keyword(s):  
Real World ◽  
Test Procedure ◽  
Accurate Estimation ◽  
Vehicle Type ◽  
Light Duty ◽  
Road Grade ◽  
Light Duty Vehicle ◽  
Curb Weight ◽  
Vehicle Activity ◽  
Light Duty Vehicles

Accurate estimation of vehicle activity is critically important for the accurate estimation of emissions. To provide a benchmark for estimation of vehicle speed trajectories such as those from traffic simulation models, this paper demonstrates a method for quantifying light-duty vehicle activity envelopes based on real-world activity data for 100 light-duty vehicles, including conventional passenger cars, passenger trucks, and hybrid electric vehicles. The vehicle activity envelope was quanti-fied in the 95% frequency range of acceleration for each of 15 speed bins with intervals of 5 mph and a speed bin for greater than 75 mph. Potential factors affecting the activity envelope were evaluated; these factors included vehicle type, transmission type, road grade, engine displacement, engine horsepower, curb weight, and ratio of horsepower to curb weight. The activity envelope was wider for speeds ranging from 5 to 20 mph and narrowed as speed increased. The latter was consistent with a constraint on maximum achievable engine power demand. The envelope was weakly sensitive to factors such as type of vehicle, type of transmission, road grade, and engine horsepower. The effect of road grade on cycle average emissions rates was evaluated for selected real-word cycles. The measured activity envelope was compared with those of dynamometer driving cycles, such as the federal test procedure, highway fuel economy test, SC03, and US06 cycles. The effect of intervehicle variability on the activity envelope was minor; this factor implied that the envelope could be quantified based on a smaller vehicle sample than used for this study.

Modeling Enleanment Emissions for Light-Duty Vehicles

1998 ◽  
Vol 1641 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Feng An ◽  
Matthew Barth ◽  
George Scora ◽  
Marc Ross
Keyword(s):  
Test Procedure ◽  
Model Development ◽  
Environmental Research ◽  
Load Reduction ◽  
Lean Burn ◽  
Emission Data ◽  
Light Duty ◽  
Hc Emissions ◽  
College Of Engineering ◽  
Light Duty Vehicles

A comprehensive modal emissions model for light-duty cars and trucks is being developed under the sponsorship of NCHRP Project 25-11. Model development has been described previously for vehicles operating under stoichiometric and enrichment conditions. A modal emissions model is presented for vehicles operated under enleanment conditions. Enleanment typically occurs with sharp deceleration or load reduction events, and sometimes during long deceleration. Under enleanment conditions, the air/fuel ratio is lean and incomplete combustion or misfire occurs. Preliminary research indicates that enleanment emissions (particularly for hydrocarbons) contribute significantly to a vehicle’s overall emissions. An enleanment emissions module has been developed on the basis of second-by-second emission measurements generated at the College of Engineering—Center for Environmental Research and Technology’s vehicle testing facility using the Federal Test Procedure, US06, and a specially designed modal emission cycle (MEC01). On the basis of more than 200 vehicles tested and modeled, lean-burn hydrocarbon emissions (HClean) account for 10 to 20 percent of the overall HC emissions under the various test cycles. HClean emission contributions vary greatly from vehicle to vehicle, ranging from near 0 to more than 30 percent of total HC emissions of individual vehicles. After detailed analysis of the second-by-second emission data over the modal emission cycle MECO1, it was found that enleanment hydrocarbons emissions are mostly associated with rapid load reduction events and long deceleration events. The former is most likely to cause extremely high levels of HC as short spikes, and the latter is mostly associated with longer-lasting HC puffs. A methodology has been developed to characterize and model enleanment hydrocarbons emissions associated with these two events. The model estimates are compared with measurements, with encouraging results.

Development of the Worldwide Harmonized Test Procedure for Light-Duty Vehicles

2015 ◽  
Vol 2503 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Biagio Ciuffo ◽  
Alessandro Maratta ◽  
Monica Tutuianu ◽  
Konstantinos Anagnostopoulos ◽  
Georgios Fontaras ◽  
...  
Keyword(s):  
Carbon Dioxide Emissions ◽  
Test Procedure ◽  
Test Results ◽  
Test Cycle ◽  
Test Procedures ◽  
United Nations Economic Commission ◽  
Vehicle Performance ◽  
Light Duty ◽  
Economic Commission ◽  
Light Duty Vehicles

To assess vehicle performance on criteria compounds, carbon dioxide emissions, and fuel energy consumption, laboratory tests are generally carried out. During these tests, a vehicle is driven on a chassis dynamometer (which simulates the resistances the vehicle encounters during its motion) to follow a predefined test cycle. In addition, all conditions for running a test must strictly adhere to a predefined test procedure. The procedure is necessary to ensure that all tests are carried out in a comparable way, following the requirements set by the relevant legislation. Test results are used to assess vehicle compliance with emissions limits or to evaluate the fuel consumption that will be communicated to customers. Every region in the world follows its own approach in carrying out these types of tests. The variations in approaches have resulted in a series of drawbacks for vehicle manufacturers and regulating authorities, leading to a plethora of different conditions and results. As a step toward the harmonization of the test procedures, the United Nations Economic Commission for Europe launched a project in 2009 for the development of a worldwide harmonized light-duty test procedure (WLTP), including a new test cycle. The objective of the study reported here was to provide a brief description of WLTP and outline the plausible pathway for its introduction in European legislation.

Effects of low temperature on the cold start gaseous emissions from light duty vehicles fuelled by ethanol-blended gasoline

2013 ◽  
Vol 102 ◽  
pp. 44-54 ◽  
Author(s):  
M. Clairotte ◽  
T.W. Adam ◽  
A.A. Zardini ◽  
U. Manfredi ◽  
G. Martini ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Start ◽  
Gaseous Emissions ◽  
Light Duty ◽  
Light Duty Vehicles

scholarly journals Characterization of Exhaust CO, HC and NOx Emissions from Light-Duty Vehicles under Real Driving Conditions

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1125
Author(s):  
Hui Mei ◽  
Lulu Wang ◽  
Menglei Wang ◽  
Rencheng Zhu ◽  
Yunjing Wang ◽  
...  
Keyword(s):  
Specific Power ◽  
Emission Measurement ◽  
Nox Emissions ◽  
Emission Rates ◽  
Gaseous Emissions ◽  
Passenger Cars ◽  
Light Duty ◽  
Driving Conditions ◽  
Hc Emissions ◽  
Light Duty Vehicles

On-road exhaust emissions from light-duty vehicles are greatly influenced by driving conditions. In this study, two light-duty passenger cars (LDPCs) and three light-duty diesel trucks (LDDTs) were tested to investigate the on-road emission factors (EFs) with a portable emission measurement system. Emission characteristics of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) emitted from vehicles at different speeds, accelerations and vehicle specific power (VSP) were analyzed. The results demonstrated that road conditions have significant impacts on regulated gaseous emissions. CO, NOx, and HC emissions from light-duty vehicles on urban roads increased by 1.1–1.5, 1.2–1.4, and 1.9–2.6 times compared with those on suburban and highway roads, respectively. There was a rough positive relationship between transient CO, NOx, and HC emission rates and vehicle speeds, while the EFs decreased significantly with the speed decrease when speed ≤ 20 km/h. The emissions rates of NOx and HC tended to increase and then decrease as the acceleration increased and the peak occurred at 0 m/s2 without considering idling conditions. For HC and CO, the emission rates were low and changed gently with VSP when VSP < 0, while emission rates increased gradually with the VSP increase when VSP > 0. For NOx NOx emission rates were lower and had no obvious change when VSP < 0. However, NOx emissions were positively correlated with VSP, when VSP > 0.

Dealing with the Gap between Type-Approval and In-Use Light Duty Vehicles Fuel Consumption and CO2 Emissions: Present Situation and Future Perspective

2018 ◽  
Vol 2672 (2) ◽  
pp. 23-32 ◽  
Author(s):  
Jelica Pavlovic ◽  
Konstantinos Anagnostopoulos ◽  
Michael Clairotte ◽  
Vincenzo Arcidiacono ◽  
Georgios Fontaras ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Real World ◽  
Test Procedure ◽  
Present Situation ◽  
Future Perspective ◽  
Type Approval ◽  
Real Driving Emission ◽  
Light Duty ◽  
The Difference ◽  
Light Duty Vehicles

There is increasing evidence suggesting that real-world fuel consumption and CO2 improvements in the last decade have been much less than those measured during type-approval tests. Scientific studies have found that the offset between officially reported values and real-world vehicle CO2 emissions in Europe has constantly increased over the last years. The difference between officially reported and actual CO2 emissions of vehicles has three main implications: (i) it undermines the effectiveness of CO2 regulations in reducing greenhouse gas emissions in Europe; (ii) it distorts competition between vehicle manufacturers; (iii) it undermines innovation. As a fundamental step to deal with this issue, the European Commission has already replaced the old and outdated test procedure used so far in the emission type-approval of vehicles with the worldwide harmonized light vehicles test procedure (WLTP). Being a lab-based test procedure, the WLTP, by its nature, can only cover part of the CO2 gap. There is therefore increasing pressure to integrate the current type-approval system with additional measures based on real-world measurements. One of the options under discussion is to use the CO2 emissions measured during the real driving emission test. The objective of the present paper is to assess the validity of this proposal and to propose other possible ways to deal with the CO2/fuel consumption gap. In particular, the paper presents experimental evidence on the variability of the CO2/fuel consumption of a vehicle, questioning the idea that a single central estimate of these quantities may be sufficient.

scholarly journals 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 ◽  
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.

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

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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