CO2 flow [m3/h], CO2 in raw exhaust [%]CO2 flow [m3/h],CO2 in tunnel [tenths of %]

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Vzorkov

Vzorková án ní í a měř a m ěřen ení í pevných pevných č č ástic pomoc á stic pomocí í improvizovan

improvizovan ého é ho plnopr plnopr ůto ů toč č n n ého é ho ředic ř edicí ího tunelu ho tunelu PARTICULATE MATTER MEASUREMENT WITH AN PARTICULATE MATTER MEASUREMENT WITH AN

IMPROVISED FULL

IMPROVISED FULL- -FLOW DILUTION TUNNEL FLOW DILUTION TUNNEL

Michal Vojtíšek^1,2, Jan Topinka³, Martin Pechout¹, Martin Mazač¹, Aleš Dittrich¹, Milan Čihák¹

Výzkumné centrum spalovacích motorů a automobilů Josefa Božka -

1 FS TU v Liberci, ²FS ČVUT Praha

3Ústav experimentální medicíny Akademie věd ČR, Praha Josef Božek Research Center for

Automobiles and Engines –

1 Faculty of Mechanical Engineering, Technical University of Liberec

2 Faculty of Mechanical Engineering, Czech Technical University in Prague

3 Institute of Experimental Medicine, Academy of Sciences of the Czech

Republic, Prague

Contact: michal.vojtisek(at)tul.cz, michal.vojtisek(at)fs.cvut.cz

tel. (+420) 774 262 854

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Motivation and goals of work

Exhaust gases from internal combustion engines contain ultrafine particles which are a recognized and serious hazard to human health. The current metric – total particulate mass – is not an adequate measure of the health risks.

Therefore, new metrics are needed to evaluate the effects of new fuels and new engine and exhaust gas aftertreatment technologies.

Advanced chemical analyses and direct toxicological assessments of diesel particulate matter often require a considerable amount of material to be collected.

As a pilot study, large volumes of particulate matter emitted by engines operated on biofuels have been collected using an improvised high-volume sampling system.

This paper reports on part of this pilot study, the goal of which was to

investigate the feasibility and validate the methodology for sampling of high volumes from an improvised full-flow dilution tunnel.

A secondary motivation was to enable particulate matter measurements in local

laboratories not equipped with one of the recognized setups – either a Constant Volume Sampler (CVS), or a partial flow dilution system with a proportional sampler.

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0 1 2 3 4 5 6

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 silniční nákladní doprava, desítky milionů tunokilometrů

prodej motorové nafty, miliony tun registrované automobily, miliony registrované nákladní vozy, statisíce

podíl dopravy na celkových emisích PM10, desítky procent

Increase in traffic intensity:

Nearly half of total PM mass in CZ originated from mobile sources

in Prague, 10.8 Gg (mil. tons) of particles annually

– this is 14-15x more than 0,7-0,8 Gg/from stationary sources

(Prague – State of the Environment 2009)

Source: Environmantel yearbook of the Czech Republic and Czech Republic national vehicle registry

Highway truck traffic, tens of million ton-km Diesel fuel sales, millions of tons

Passenger car registrations Heavy truck registrations

Contribution of transport to PM10, tens of %

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Typical diesel particle size distributions (number and volume weighing)

Kittelson, J. Aerosol Sci. Vol. 29, No. 5/6, pp. 575-588, 1998

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Lung particle capture efficiency Lung particle capture efficiency

A. Mayer, 12th ETH Conference on Combustion Generated Nanoparticles, Zurich, 2008

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Muir, R. et al., High-level symposium on nanotechnology safety, Praha, 30.11.2011

Lung particle capture efficiency

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B. Alfoldy et al., Aerosol Science 40 (2009) 652—663.

Lung deposition fraction:

ET – extrathoracic TB – tracheobronchial

PU – pulmonary

Particle mass median diameter:

NM – nucleation mode AM – accumulation mode

Lung particle capture efficiency

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Penetration of

Penetration of nanoparticles nanoparticles through through cell membranes (and into bloodstream) cell membranes (and into bloodstream)

1000 nm

Polystyrene Particles

78 nm

Polystyrene Particles

Barbara Rothen-Rutishauer, as quoted by A. Mayer, 12th ETH Conference on Combustion Generated Nanoparticles

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Traffic

Traffic- -generated particles are highest generated particles are highest near major roadways

near major roadways

Inkrementální PM_2.5 koncentrace z těžkých

vozidel se vznětovými motory (průjezd ve směru modrých šipek)

US EPA models, modeling by

US EPA models, modeling by KonheimKonheim & Ketcham& Ketcham, Brooklyn, New York, Brooklyn, New York

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Spatial distribution of PM

₁₀

concentrations

(ATEM / Praha – State of the Environment 2009)

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Spatial distribution of sources of PM

(Czech hydrometeorological institute)

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Current particulate matter measurement standards might not accurately reflect health effects

x 1,000 x 1,000,000

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Mikroskopické pevné částice vznikající spalováním jsou jedna z nejčastějších příčin předčasného úmrtí.

V Kalifornii zabíjejí více lidí, než dopravní nehody, a

přibližně stejně jako druhotný cigaretový kouř.

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“Fine particulate matter (PM2,5) is responsible for significant negative impacts on human health. Further, there is as yet no identifiable threshold below which PM2,5 would not pose a risk. As such, this pollutant should not be regulated in the same way as other air pollutants. The approach should aim at a general reduction of concentrations in the urban background to ensure that large sections of the population benefit from improved air quality. However, to ensure a minimum degree of health protection everywhere, that approach should be combined with a limit value, which is to be preceded in a first stage by a target value.”

(Preambule to 2008/50/EC)

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Reference method:

Partial-flow dilution tunnel

Belasch system - in-house construction at TUL Partial flow tunnel, with dilution ratio controlled by hand and monitored as ratio of concentrations of CO2

in raw/diluted exhaust

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Alternate method:

Improvised full-flow dilution tunnel

Laboratory main exhaust duct used as an improvised full-flow

dilution tunnel

Sampling ports for particulate sizing (EEPS)

and for gravimetric measurement

Sampling ports for high-volume samplers for toxicological

assays

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High-volume sampling of PM for toxicological assays

High-volume samplers

(Digitel, normally used for ambient air quality measurements, here adapted for use with diluted diesel exhaust)

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High-volume sampling of PM for toxicological assays

~ 150 11-13

Filter active area [cm²]

150 47

Filter diameter [mm]

150 47

Filter diameter [mm]

3 000 – 20 000 50 - 500

Mass of PM deposited [ug]

10 - 100

~ 0.1 – 0.5 Sampled volume [m³]

500-1000 30-50

Sampling rates [l/min]

High-vol sampler Conventional

High-volume Digitel samplers vs. conventional gravimetric measurements:

For toxicological assays and advanced chemical characterization, large quantities

of PM are needed – about two orders of magnitude more than for gravimetric measurement… usually, full-flow dilution

tunnel / CVS system is used.

Results of these studies have been presented:

Vojtíšek et al., Ovzduší 2011 Škrdlíková et al., Ovzduší 2011

Topinka et al., ETH Conference on Combustion Generated Nanoparticles, 2011

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0 10 20 30 40 50 60 70

10:28:00 10:36:00 10:44:00 10:52:00 11:00:00 11:08:00 11:16:00 11:24:00 time (Oct 27, 2010) CO2 flow [m3/h], CO2 in raw exhaust [%]

0 10 20 30 40 50 60 70 14:17:00 14:19:00 14:21:00 14:23:00 14:25:00 14:27:00 14:29:00 14:31:00 14:33:00 14:35:00time (Dec 10, 2010)14:37:00

CO2 flow [m3/h], CO2 in tunnel [tenths of %]

CO2 flow from engine [normalized m3/h] CO2 from engine (in raw exhaust) [%] - ESC - Oct 27 CO2 flow in tunnel [normalized m3/h] CO2 in tunnel [hundreds of ppm] - modified ESC - Dec 10

13-mode ESC test, 4 minutes per mode

13-mode ESC test, 1000 seconds total, time at each mode proportional to the weight of the corresponding mode, 20 s transition between modes

4 minutes per mode

mode 7

mode 11

mode 13

Comparison between engine-out and tunnel CO

₂

flows

- at the engine: instantaneous CO₂ concentrations x instantaneous exhaust mass flow

- in the full-flow dilution tunnel: instantaneous CO₂ concentrations x assumed flow (const.)

ESC test - for tunnel measurements, length at each mode proportional to the weight of that mode, with 20-s transitions between modes

Improvised dilution tunnel:

Validation of CO

₂

flows

(data from two different ESC tests)

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Particle size distribution measurements (Engine Exhaust Particulate Sizer)

Sampling from the improvised dilution tunnel

(dilution ratio 15:1-100:1)

Good repeatability for total particle number and volume

Additional dilution necessary

Additional dilution system (max. 10:1)

EEPS 10 lpm

flow HEPA

filter

Mass flow controller 0-10 lpm Sample

from tunnel

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Cummins ISBe4 engine, no aftertreatment

Diesel fuel, biodiesel and heated fuel-grade rapeseed oil

Particle volume measured by EEPS sampling from the improvised tunnel, with 3.5:1 additional dilution

ESC test - for tunnel measurements, length at each mode proportional to the weight of that mode, with 20-s transitions between modes

(Vojtíšek, Lozano, Pechout, SAE Technical Paper Series 2011-24-0104)

Improvised dilution tunnel:

Total particle number (EEPS)

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Improvised dilution tunnel:

Total particle volume (EEPS)

Cummins ISBe4 engine, no aftertreatment

Diesel fuel, biodiesel and heated fuel-grade rapeseed oil

Particle volume measured by EEPS sampling from the improvised tunnel, with 3.5:1 additional dilution

ESC test - for tunnel measurements, length at each mode proportional to the weight of that mode, with 20-s transitions between modes

(Vojtíšek, Lozano, Pechout, SAE Technical Paper Series 2011-24-0104)

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0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

Apr 27, 2011, Diesel fuel, 1480 rpm, full load Apr 27, 2011, Diesel fuel, 1480 rpm, 112 Nm Apr 27, 2011, Rapeseed oil, 1480 rpm, full load Apr 27, 2011, Rapeseed oil, 1480 rpm, 112 Nm Apr 27, 2011, Rapeseed oil+10% BuOH, 1480 rpm, full load Apr 27, 2011, Rapeseed oil+10% BuOH, 1480 rpm, 112 Nm May 17, 2011, Diesel fuel, 1480 rpm, full load October 21, 2008, Diesel fuel, 1480 rpm, full load May 17, 2011, Rapeseed oil, 1480 rpm, full load October 21, 2008, Rapeseed oil, 1480 rpm, full load

PM emissions [g/kWh]

Partial flow B Partial flow A Full-flow

All sampling on same 47-mm PallFlex T60A20 borosilicate glass fluorocarbon-coated filters Reference: Partial flow tunnel (Belasch) – filter holders A and B

Alternate method: Sampling from the exhaust duct, flow controlled by a rotameter

Improvised dilution tunnel:

Comparison of PM measurements

Sets of simultaneous measurements

Measurements on different days

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Conclusions Conclusions

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The feasibility of using laboratory exhaust duct as an improvised full-flow dilution tunnel with a dilution ratio on the order of 10:1-100:1 for particulate

matter measurement and sampling was investigated here.

The CO₂ flows (a) from the engine, determined from measured intake air flow and measured CO₂ concentrations in raw exhaust, and (b) in the tunnel, determined from

measured CO₂ concentrations and constant assumed flow through the tunnel, were comparable with differences within about 10%.

The PM mass emissions, measured by the gravimetric method during steady-state engine operation with sampling using (a) a partial flow sampling system and (b) the improvised full-

flow tunnel, were comparable, with differences within the uncertainty of PM measurement..

The particle number and particle volume data, collected over multiple repetitions of ESC cycles using different fuels, were generally repeatable, with no established reference to

compare to.

The experiences were generally positive, with some indication of the feasibility of this method, at least for preliminary measurements, in places where a „normal“

full-flow dilution system is not available.

The deposition and reentrainment of particles and volatile compounds have not been, and should be, further investigated for advanced analyses and toxicological assays.

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Acknowledgements

The experimental work reported on here was conducted at TU Liberec and was funded by the Czech Science Foundation grant no.

101/08/1717: Optimization of combustion of vegetable oils in diesel engines, and by the Czech Ministry of Education grant no.

1M0568: Josef Božek Research Center for Engines and Automobile Engineering.

The review and analysis of the data was carried on at Czech Technical University within the Josef Božek Research Center and at TUL within the project MEDETOX: Innovative Methods of Monitoring of Diesel Engine Exhaust Toxicity in Real Urban Traffic, financed by