concawe concawe Nanoparticles from road vehicle Nanoparticles from road vehicle exhaust: an artefact or a exhaust: an artefact or a reality? reality? Diane Hall BP/CONCAWE Diane Hall BP/CONCAWE Lemnos Meeting: Round Table Discussion 11 th September 2003 concawe concawe
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Concawe Nanoparticles from road vehicle exhaust: an artefact or a reality? Diane Hall BP/CONCAWE Lemnos Meeting: Round Table Discussion 11 th September.
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Nanoparticles from road vehicle Nanoparticles from road vehicle exhaust: an artefact or a reality?exhaust: an artefact or a reality?
Diane Hall BP/CONCAWEDiane Hall BP/CONCAWE
Lemnos Meeting: Round Table Discussion
11th September 2003
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Purpose of DiscussionPurpose of Discussion
To examine data which demonstrates the emission of nanoparticles from vehicles and engines
To understand whether these measurements reflect genuine real-time engine emissions or are affected by sampling and/or methodology
•First research – had no explanation for consistency of distribution between vehicles
•Possible explanation is that we were not seeing genuine engine emissions
Source: concawe report 98/51
Gasoline vehicles at 120km/h
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Diesel vehicles
No. / km
10**10
10**11
10**12
10**13
10**14
10**15
50 km/h 120 km/h Hot MVEG
Gasoline vehicles
Total number of particles emitted per Total number of particles emitted per kilometer for each vehiclekilometer for each vehicle
Source: CONCAWE Report 98/51; SAE paper 982600Source:concawe report 98/51
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• Accumulation mode particles stabilise instantaneously• Nucleation mode particles take time to stabilise
Stabilisation time is importantStabilisation time is important
Source: concawe report 01/51
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• Accumulation mode unaffected by dilution ratio• Nucleation mode sensitive to dilution ratio• Temperature (rather than dilution ratio) is believed to be the dominating influence on
nucleation particle formation
Nucleation mode sensitive toNucleation mode sensitive to temperaturetemperature
Source: concawe report 01/51
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0.0E+0
2.0E+8
4.0E+8
6.0E+8
8.0E+8
1.0E+9
1.2E+9
1.4E+9
1 10 100 1000
Particle Diameter (nm)
Dilu
tio
n C
orr
ec
ted
Co
nc
en
tra
tio
n (
dW
/dlo
gD
p)/
cm
3
MODE1;R49#1
MODE7;R49#1
MODE13;R49#1
DETR/SMMT/CONCAWE Particulate Research Programme
•Size of idle mode appears dependent on preceding test condition
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Implications from studiesImplications from studies
Nanoparticles are emitted from Gasoline vehicles at high speed, independent of fuel and vehicle technology
Nanoparticles emitted during heavy duty engine testing are sensitive to sampling conditions
Nanoparticles measured during heavy duty testing are sensitive to preceding engine history
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BP Study – gasoline particle emissions at BP Study – gasoline particle emissions at 120km/h (measured over a week)120km/h (measured over a week)
Source: SAE 2000-01-2957
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Relationship of particle emissionsRelationship of particle emissionswith temperaturewith temperature
Source: SAE 2000-01-2957
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On-road testsOn-road tests
Source: SAE 2000-01-2957
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IndicationsIndications
continual running at high speed was ‘clearing’ the system of particles
material appeared to be laid down on surfaces at cooler conditions with particle release appearing to be temperature related
Hypothesis tested with cut off piece of exhaust sampling pipe
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Tests on old exhaust pipeTests on old exhaust pipe
Source: SAE 2000-01-2957
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TEST PROGRAMMETEST PROGRAMME
Vehicle: VW Golf 1.9l TDi, with and without oxicat
Fuels: Current EN 590 (300ppm S) Swedish Class 1
Chassis Dynamometer at BP, with measurements by AEA Technology SMPS (7-320nm); UPM total count >3nm
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RESULTSRESULTS
At road load, no nucleation particles were observed at any of the test conditions, with either fuel and independent of the presence of the catalyst
Tests were repeated at high load (30kW)
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Summary of High Load Tests at 50km/hSummary of High Load Tests at 50km/h
0.0E+00
1.0E+08
2.0E+08
3.0E+08
4.0E+08
5.0E+08
6.0E+08
7.0E+08
8.0E+08
9.0E+08
1.0E+09
EN590 EN590+CAT Swedish Swedish+CAT
Part
icle
concentr
ation [#/c
c]
SMPS
UPM
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SummarySummary
Nucleation particles were not seen under any test condition at road load
Nucleation particles were only seen at high load with the catalyst in place appear to be temperature related
The formation of nanoparticles (nucleation mode) is extremely sensitive and varies with sampling (temperature, dilution, humidity); thus repeatable measurement requires tight control and carefully defined conditions
High concentrations of small particles have been measured from gasoline vehicles operating at high speeds and from Diesel vehicles at high load
These particles have been shown to be strongly linked to the temperature of both the exhaust and sampling system
Material emitted from the engine is deposited on cool surfaces and released as particles as the temperature profile increases
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Conclusions (2)Conclusions (2)
Sustained periods of high temperature will ‘clean’ the system and reduce the number concentration to that measured at low speed
Subsequent operation at progressively higher speeds will result in further release of deposited material
The measurement of particle numbers is strongly dependent on the pre-history of both vehicle and sampling system
Further research continues to be needed to understand the formation mechanism and atmospheric fate of nucleation particles