scholarly journals Charging-Based PN Sensing of Automotive Exhaust Particles

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 805
Author(s):  
Mario Anton Schriefl ◽  
Matthias Longin ◽  
Alexander Bergmann
Keyword(s):  
Particle Number ◽  
Motor Vehicles ◽  
Promising Alternative ◽  
Particle Properties ◽  
Exhaust Particles ◽  
Size And Morphology ◽  
Diffusion Charging ◽  
Dc Sensor ◽  
Mobile Measurement ◽  
Emission Legislation

Mobile measurement of particle number concentration (PN) in the exhaust of motor vehicles has recently become an integral part of emission legislation. Charge-based sensing techniques for the examination of PN, like Diffusion Charging (DC), represent a promising alternative to condensational particle counters (CPCs) as established PN sensors, because they enable to build robust, compact and energy efficient systems. However, due to the charging process, particle properties like size and morphology have a big impact on the sensor’s PN response. For particles of different size and shape we experimentally investigated those impacts using own-built charging-based sensors. The PN response of the DC sensor showed desired behavior for compact NaCl particles, but less satisfying behavior for combustion aerosol standard (CAST) particles, which is a widely used test aerosol for automotive applications. With a photoelectric charger, the PN response of CAST particles was significantly better.

scholarly journals Determination of car on-road black carbon and particle number emission factors and comparison between mobile and stationary measurements

2015 ◽  
Vol 8 (1) ◽  
pp. 43-55 ◽  
Author(s):  
I. Ježek ◽  
L. Drinovec ◽  
L. Ferrero ◽  
M. Carriero ◽  
G. Močnik
Keyword(s):  
Black Carbon ◽  
Particle Number ◽  
Emission Factors ◽  
Emission Measurement ◽  
Stationary Method ◽  
Characteristic Value ◽  
Portable Emission Measurement System ◽  
Specific Distribution ◽  
Mobile Measurement

Abstract. We have used two methods for measuring emission factors (EFs) in real driving conditions on five cars in a controlled environment: the stationary method, where the investigated vehicle drives by the stationary measurement platform and the composition of the plume is measured, and the chasing method, where a mobile measurement platform drives behind the investigated vehicle. We measured EFs of black carbon and particle number concentration. The stationary method was tested for repeatability at different speeds and on a slope. The chasing method was tested on a test track and compared to the portable emission measurement system. We further developed the data processing algorithm for both methods, trying to improve consistency, determine the plume duration, limit the background influence and facilitate automatic processing of measurements. The comparison of emission factors determined by the two methods showed good agreement. EFs of a single car measured with either method have a specific distribution with a characteristic value and a long tail of super emissions. Measuring EFs at different speeds or slopes did not significantly influence the EFs of different cars; hence, we propose a new description of vehicle emissions that is not related to kinematic or engine parameters, and we rather describe the vehicle EF with a characteristic value and a super emission tail.

scholarly journals Size-resolved particle number and volume emission factors for on-road gasoline and diesel motor vehicles

2010 ◽  
Vol 41 (1) ◽  
pp. 5-12 ◽  
Author(s):  
George A. Ban-Weiss ◽  
Melissa M. Lunden ◽  
Thomas W. Kirchstetter ◽  
Robert A. Harley
Keyword(s):  
Particle Number ◽  
Emission Factors ◽  
Motor Vehicles ◽  
Volume Emission

scholarly journals Increase in particle number emissions from motor vehicles due to interruption of steady traffic flow

2009 ◽  
Vol 14 (7) ◽  
pp. 521-526 ◽  
Author(s):  
E.R. Jayaratne ◽  
L. Wang ◽  
D. Heuff ◽  
L. Morawska ◽  
L. Ferreira
Keyword(s):  
Traffic Flow ◽  
Particle Number ◽  
Motor Vehicles

scholarly journals Sensitivity of global cloud condensation nuclei concentrations to primary sulfate emission parameterizations

2011 ◽  
Vol 11 (5) ◽  
pp. 1949-1959 ◽  
Author(s):  
G. Luo ◽  
F. Yu
Keyword(s):  
Boundary Layer ◽  
Compensation Effect ◽  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Nucleation And Growth ◽  
Ambient Atmosphere ◽  
Condensation Nuclei ◽  
Growth Processes ◽  
Particle Properties ◽  
The Impact

Abstract. The impact of primary sulfate emissions on cloud condensation nuclei (CCN) concentrations, one of the major uncertainties in global CCN predictions, depends on the fraction of sulfur mass emitted as primary sulfate particles (fsulfate), the fraction of primary sulfate mass distributed into the nucleation mode particles (fnucl), and the nucleation and growth processes in the ambient atmosphere. Here, we use a global size-resolved aerosol microphysics model recently developed to study how the different parameterizations of primary sulfate emission affect particle properties and CCN abundance. Different from previous studies, we use the ion-mediated nucleation scheme to simulate tropospheric particle formation. The kinetic condensation of low volatile secondary organic gas (SOG) (in addition to H2SO4 gas) on nucleated particles is calculated based on our new scheme that considers the SOG volatility changes arising from the oxidation aging. Our simulations show a compensation effect of nucleation to primary sulfate emission. We find that the change of fnucl from 5% to 15% has a more significant impact on the simulated particle number budget than that of fsulfate within the range of 2.5–5%. Based on our model configurations, an increase of fsulfate from 0% to 2.5% (with fnucl = 5%) does not improve the agreement between simulated and observed annual mean number concentrations of particles >10 nm at 21 stations but further increase of either fsulfate from 2.5% to 5% (with fnucl = 5%) or fnucl from 5% to 15% (with fsulfate = 2.5%) substantially deteriorates the agreement. For fsulfate of 2.5%–5% and fnucl of 5%, our simulations indicate that the global CCN at supersaturation of 0.2% increases by 8–11% in the boundary layer and 3–5% in the whole troposphere (compared to the case with fsulfate=0).

scholarly journals Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber

2012 ◽  
Vol 12 (4) ◽  
pp. 2205-2214 ◽  
Author(s):  
J. Voigtländer ◽  
J. Duplissy ◽  
L. Rondo ◽  
A. Kürten ◽  
F. Stratmann
Keyword(s):  
Particle Number ◽  
Response Times ◽  
Galactic Cosmic Rays ◽  
Particle Model ◽  
Particle Nucleation ◽  
Aerosol Dynamics ◽  
Particle Properties ◽  
Size Standard ◽  
Mean Size ◽  
Log Normal

Abstract. To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmics Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26.1 m3 tank at CERN (Switzerland). In the experiments, the effect of ionizing radiation on H2SO4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional computational fluid dynamics (CFD) – particle model. In the model the coupled fields of gas/vapor species, temperature, flow velocity and particle properties were computed to investigate mixing state and mixing times of the CLOUD tank's contents. Simulation results show that a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, two fans and sufficiently high fan speeds are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio were found to be in the order of few minutes. Particle nucleation and growth was also simulated and particle number size distribution properties of the freshly nucleated particles (particle number, mean size, standard deviation of the assumed log-normal distribution) were found to be distributed over the tank's volume similar to the gas species.

scholarly journals Characterization of particle number counters based on pulsed-mode diffusion charging

2020 ◽  
Vol 54 (7) ◽  
pp. 772-789 ◽  
Author(s):  
M. A. Schriefl ◽  
R. T. Nishida ◽  
M. Knoll ◽  
A. M. Boies ◽  
A. Bergmann
Keyword(s):  
Particle Number ◽  
Pulsed Mode ◽  
Diffusion Charging

scholarly journals Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Julia Schmale ◽  
Silvia Henning ◽  
Bas Henzing ◽  
Helmi Keskinen ◽  
Karine Sellegri ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Radiative Forcing ◽  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Size Distributions ◽  
Atmospheric Conditions ◽  
Condensation Nuclei ◽  
Retrieval Method ◽  
Particle Properties ◽  
Aerosol Cloud Interactions

Abstract Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data. The observatories represent nine different environments, e.g., Arctic, Atlantic, Pacific and Mediterranean maritime, boreal forest, or high alpine atmospheric conditions. This is a unique collection of aerosol particle properties most relevant for studying aerosol-cloud interactions which constitute the largest uncertainty in anthropogenic radiative forcing of the climate. The dataset is appropriate for comprehensive aerosol characterization (e.g., closure studies of CCN), model-measurement intercomparison and satellite retrieval method evaluation, among others. Data have been acquired and processed following international recommendations for quality assurance and have undergone multiple stages of quality assessment.

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