IMPACTS OF AMBIENT TEMPERATURE AND PRESSURE ON PM2.5 EMISSION PROFILES OF LIGHT-DUTY DIESEL VEHICLES

2012 ◽  
Vol 11 (06) ◽  
pp. 1240037
Author(s):  
CHENYU WANG ◽  
YE WU ◽  
ZHENHUA LI ◽  
JIMING HAO
Keyword(s):  
Ambient Temperature ◽  
Size Distribution ◽  
Ambient Pressure ◽  
Passenger Cars ◽  
Test Range ◽  
Diesel Vehicles ◽  
Light Duty ◽  
Mass Size ◽  
Temperature And Pressure ◽  
The Impact

The impact of the environmental factors on the emissions of particulate matter (PM) number, size distribution and mass size distribution from diesel passenger cars was evaluated. Particle measurements from five modern light-duty diesel vehicles (LDDV) were performed in June and November 2011. Commercial low sulfur diesel fuel (less than 50 ppm) was used during the testing of these vehicles which were not equipped with after-treatment devices. The dynamometer test was based on the Economic Commission of Europe (ECE) 15 cycles. The results indicate that PM2.5 emissions from LDDV are significantly affected by ambient temperature and pressure. A comparison of the emissions concentration of PM2.5 in these two different months showed that the number concentration in June was (3.8 ± 0.69) × 107 cm-3 and (2.5 ± 0.66) × 107 cm-3 in November. The PM concentration of about 30 nm diameter was 25 ± 6% of the total emissions in November while only 14 ± 3% of total emissions in June. In the 60 nm to 2.5 μm test range, November data shows less of a contribution for number than data from June testing. The concentration of mass emissions in June was (325 ± 44) mg/m3 and (92 ± 30) mg/m3 in November. The contribution of the number of PM particles in November testing is lower than testing in June by 34% and the mass concentration in November is 70% lower than that in June. With the decrease of ambient temperature and the increase of ambient pressure, both the oxygen concentration in cylinder and air–fuel ratio are increased, which caused lower particle number and mass emissions during November testing. The size distribution is also altered by these changes: the more efficient in-cylinder combustion resulted in a higher proportion of particles in the 30 nm and smaller range than for other particle sizes.

scholarly journals Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

2016 ◽  
Vol 16 (2) ◽  
pp. 777-797 ◽  
Author(s):  
A Vara-Vela ◽  
M. F. Andrade ◽  
P. Kumar ◽  
R. Y. Ynoue ◽  
A. G. Muñoz
Keyword(s):  
Size Distribution ◽  
Metropolitan Area ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Sao Paulo ◽  
Vehicular Emissions ◽  
São Paulo ◽  
Mass Size Distribution ◽  
Mass Size ◽  
The Impact

Abstract. The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the ultraviolet radiation and induced a decrease in ozone formation. The ground-level O3 concentration decreased by about 2 % when the aerosol-radiation feedback is taken into account.

scholarly journals Testing and evaluation of cold-start emissions from a gasoline engine in RDE test at two different ambient temperatures

2021 ◽  
Vol 11 (1) ◽  
pp. 425-434
Author(s):  
Jacek Pielecha ◽  
Kinga Skobiej ◽  
Karolina Kurtyka
Keyword(s):  
Ambient Temperature ◽  
Gasoline Engine ◽  
Cold Start ◽  
Exhaust Emissions ◽  
Operating Parameters ◽  
Time Interval ◽  
Vehicle Speed ◽  
Passenger Cars ◽  
Ambient Temperatures ◽  
The Impact

Abstract In order to better reflect the actual ecological performance of vehicles in traffic conditions, both the emission standards and the applied emission tests are being developed, for example by considering exhaust emissions for a cold engine start. This article presents the research results on the impact of ambient temperature during the cold start of a gasoline engine in road emission tests. The Real Driving Emissions (RDE) tests apply to passenger cars that meet the Euro 6 emissions norm and they are complementary to their type approval tests. A portable emissions measurement system was used to record the engine and vehicle operating parameters, as well as to measure the exhaust emissions during tests. This allowed for parameters such as engine load, engine speed and vehicle speed to be monitored. The cold start conditions for two different temperatures (8°C and 25°C) were compared in detail. Moreover, the engine operating parameters, exhaust concentration values and road emissions for the 300 s time interval, were compared. The summary of the article presents the share of a passenger car’s cold start phase for each exhaust compound in the urban part of the test and in the entire Real Driving Emissions test depending on the ambient temperature.

Effective N2 capture by aryl cations at ambient temperature and pressure

2021 ◽  
Author(s):  
Xia Xu ◽  
Jianxiong Dai ◽  
Xing Guo ◽  
Cheng Qian ◽  
Pei Zhang ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Ambient Pressure ◽  
Plasma Discharge ◽  
Temperature And Pressure

N2 molecules are effectively captured by arylium cations generated via plasma discharge of arlyhalides at ambient pressure and temperature, exclusively producing relatively stable aryldiazaonium in a well-defined ion–molecule association manner.

scholarly journals Ambient Temperature and Pressure Corrections for Aircraft Gas Turbine Idle Pollutant Emissions

1976 ◽  
Author(s):  
J. W. Marzeski ◽  
W. S. Blazowski
Keyword(s):  
Ambient Temperature ◽  
Ambient Pressure ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Emission Model ◽  
Correction Factors ◽  
Ambient Conditions ◽  
Temperature And Pressure

Recent investigations have indicated that aircraft engine exhaust emissions are sensitive to ambient conditions. This paper reports on combustor rig testing intended to evaluate variations due to ambient temperature and pressure with special emphasis on idle engine operating conditions. Empirically determined CO, CxHy, and NOx correction factors — the ratio of the pollutant emission index value obtained during standard day operation to that resulting during actual ambient conditions — are presented. The effects of engine idle cycle pressure ratio, primary zone fuel-air ratio, and fuel type were investigated. Ambient temperature variations were seen to cause substantial emission changes; correction factors in excess of 2.0 were determined in some cases. Ambient pressure variations were found to be less substantial. A previously published NOx emission model and a simplified hydrocarbon combustion analysis are shown to be in general agreement with the empirical results.

scholarly journals Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

2015 ◽  
Vol 15 (10) ◽  
pp. 14171-14219 ◽  
Author(s):  
A. Vara-Vela ◽  
M. F. Andrade ◽  
P. Kumar ◽  
R. Y. Ynoue ◽  
A. G. Muñoz
Keyword(s):  
Size Distribution ◽  
Metropolitan Area ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Sao Paulo ◽  
Vehicular Emissions ◽  
São Paulo ◽  
Mass Size Distribution ◽  
Mass Size ◽  
The Impact

Abstract. The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 μm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. Weather Research and Forecasting with Chemistry (WRF-Chem) model is used as photochemical modelling tool to describe the physico-chemical processes leading to evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The study period during a month, between 7 August and 6 September 2012, is considered to perform the numerical simulations due to the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. Results show that the emission of primary gases from vehicles led to a production between 20 and 30% due to new particles formation in relation to the total mass concentration of PM2.5 in the downtown SPMA. Dust and sea-salt aerosols contributed with 40–50% of the total PM10 (PM10; ≤ 10 μm in diameter) concentration. Furthermore, ground level O3 concentration decreased by about 2% when the aerosol-radiation feedback is taken into account. Over 40% of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. An increase in the number of small particles impaired the ultraviolet radiation and induced a decrease in ozone formation. Availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model, which simulates feedbacks between meteorological variables and chemical species, made possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition in addition to evaluate its formation potential through the gas-to-particle conversion processes.

Characterization of Un-stabilized Orthorhombic Zirconia Synthesized at Ambient Temperature and Pressure

2012 ◽  
Vol 1406 ◽  
Author(s):  
Miriam P. Trubelja ◽  
Donald Potter ◽  
Claudia Rawn ◽  
Karren More ◽  
Joseph J. Helble
Keyword(s):  
Ambient Temperature ◽  
Oxygen Vacancies ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Critical Factor ◽  
Orthorhombic Structure ◽  
Elevated Pressures ◽  
Temperature And Pressure ◽  
Bulk Structures

ABSTRACTBulk structures of un-stabilized ZrO2-x with x in the 0 ≤ x ≤ 0.44 range under ambient pressure exist in three different structures (monoclinic, tetragonal and cubic). At ambient temperature and elevated pressures above 3.5 GPa, zirconia, at these compositions, a fourth phase is found, the orthorhombic structure. A dilute sol-gel method was used to produce nanoscale zirconia particles containing the unstabilized orthorhombic cotunnite structure for use in this project. Extensive characterization of this material indicates that the critical factor in determining the synthesized structures appears to be the number and placement of oxygen vacancies. These results also indicate that surface energy alone is not the controlling factor in determining the crystal structure synthesized.

The Measuring of Sodium Droplet Size Distribution and its Impact on the Consequence of Sodium Spray Fire

2017 ◽  
Author(s):  
Wang Guozhi ◽  
Du Haiou ◽  
Wang Rongdong ◽  
Shi Wentao ◽  
Piao Jun
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Input Data ◽  
Drop Size ◽  
Droplet Size Distribution ◽  
Drop Size Distribution ◽  
Liquid Sodium ◽  
The Real ◽  
Temperature And Pressure ◽  
The Impact

The sodium droplet size distribution has significant impact on the consequence of sodium spray fire. And it is fundamental input data for the validation and application of sodium spray fire code. The experiments were carried out in a closed vessel to measure the sodium droplet size distribution. Liquid sodium of 250 °C was sprayed downward into the vessel in the form of sodium droplets through a nozzle with a diameter of 2.4mm. The vessel was inerted by argon gas to prevent the sodium droplets from burning. A real time spray droplet sizing system based on ensemble diffraction technique was used to measure the size of the droplets. And the laser beam was passed through two glass windows on the wall of the vessel to reach the sodium droplets. The tests showed that the sizes of the sodium droplets ranged from 184μm to 1000μm at the nozzle pressure of 0.15MPa. And median diameter was 532μm. The sodium spray fire code named NACOM was used to evaluate the impact of particle size distribution on sodium fire. The measured sodium droplets size distribution and the Nukiyama-tanasama drop size distribution were divided into 11 groups to be used as input data for the NACOM code. A comparison showed that 23% of particles in Nukiyama-tanasama drop size distribution were over 1000μm, while the largest size of particles in the measured sodium droplets was 1000μm. The calculation by NACOM code showed that the trend and value of temperature and pressure in the vessel were similar, so to some extent Nukiyama-tanasama drop size distribution is a good approximation of the real sodium droplet size distribution. However, Nukiyama-tanasama drop size distribution may be unsuitable for application in sodium fire safety analysis, because the temperature and pressure calculated from which was lower than that of the real droplet size distribution.

scholarly journals Cold start emissions of passenger cars with gasoline and diesel engines in Real Driving Emissions tests

2019 ◽  
Vol 179 (4) ◽  
pp. 160-168 ◽  
Author(s):  
Jacek PIELECHA ◽  
Jerzy MERKISZ ◽  
Karolina KURTYKA ◽  
Kinga SKOBIEJ
Keyword(s):  
Ambient Temperature ◽  
Diesel Engines ◽  
Test Procedure ◽  
Cold Start ◽  
Exhaust Emissions ◽  
Exhaust Emission ◽  
Passenger Cars ◽  
Compression Ignition Engines ◽  
Vehicle Operation ◽  
The Impact

Modernization of passenger cars and constant development of existing legislation lead to a reduction of exhaust emissions from these vehicles. In accordance with package 3 of the RDE test procedure, the European Commission has extended testing methods by including exhaust emissions during a cold start. The article compares the research results on the impact of ambient temperature during the cold start of spark-ignition and compression-ignition engines in road emission tests. The tests were carried out in line with the requirements of the RDE test procedure for passenger cars meeting the Euro 6d-Temp emissions standard. The obtained results were analyzed, i.e. there were compared the engine and vehicle operation parameters and the values of road exhaust emissions, during the cold start of gasoline and diesel engines at the ambient temperature of approximately 25oC.The summary presents the share of cold start phase of a passenger car (at the ambient temperature of around 25oC) for each exhaust emission compound in the urban part of the test, and in the entire RDE test, depending on the engine type used.

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