inter-laboratory comparison exercise cpc calibration
TRANSCRIPT
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Inter-Laboratory Comparison ExerciseCPC CALIBRATIONCALIBRATION AEROSOLS AND LABORATORY SETUPS
2016-10-12Alexander Terres
Intermediate Status Report
MOTIVATION
- Comparison of Calibration Aerosols
- Comparison of Laboratory Setups
- Suitability for Calibration sub-23nm ?
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 2
CPC CALIBRATION ROUND ROBIN SCHEDULE
TIME LABORATORY Type
02 / 2016 TSI Germany Instrument Manufacturer
03 / 2016 JRC Research Institute
04 – 05 / 2016 AVL Austria Instrument Manufacturer
06 – 07 / 2016 PTB National Metrological Institute
07 – 08 / 2016 BMW Vehicle Manufacturer
09 – 10 / 2016 Ricardo Energy & Environment Calibration Service
11 / 2016 VW Vehicle Manufacturer
12 / 2016 TSI Germany Instrument Manufacturer
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 3
We are here
REFERENCE DEVICES & CALIBRATION
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 4
LABORATORY REFERENCE INSTRUMENT CALIBRATION TYPE
TSI Germany Aerosol Electrometer National Metrological Institute
JRC Aerosol ElectrometerCPC
Manufacturer CalibrationIn-house
AVL Austria Aerosol Electrometer Manufacturer Calibration
PTB Aerosol Electrometer In-house
BMW Germany Aerosol ElectrometerCPC
Manufacturer CalibrationManufacturer Calibration
Ricardo Energy & Environment CPC National Metrological Institute
VW Germany Aerosol ElectrometerCPC
Manufacturer CalibrationIn-house
LABORATORY SETUPS
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 5
Device under test
Reference
Dilutionbridge
Source DMA
Y-Splitter
Splitter-type: ISO 27891 compliant setup
Device under test
Reference
Source DMA
Sampling volume-type: not ISO 27891 compliant
Device under test
Sampling volume
Dilu
tion
Air
TESTING PROCEDURES: COUNTING EFFICIENCY
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 6
0%
20%
40%
60%
80%
100%
120%
0 20 40 60 80 100 120 140 160
Co
un
tin
g Ef
fici
ency
Mobility Diameter [nm]
Reference Electrometer
Extra Engine Exhaust CPC
Mobility Diameter 10 15 23 41 70 100
Corresponding Diameter,Double Charges
- - 33 59 103 150
Burner Operating Point A A B C D E
Motivation Sub-23 Sub-23 PMP PMP Linearity PN-PEMS
TESTING PROCEDURES: COUNTING EFFICIENCY
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 7
Measurement
• Recording uncorrected Raw Data
• No K-factor on devices under test
• Averaging time: 60-240 seconds
Flow
• Correction: Nominal / actual Flow
• Flow measurement: Volume or Mass
Charges
• Correction for double charges
• Charge distribution: Wiedensohler
• No correction for triple charges
• No correction <23nm
Splitter Bias: Only corrected in certain labsrequired in ISO 27891
Electrometer Zero: Not correctedTo be applied in the future?
Critical when using reference Electrometer
Influenced by:Aerosol characteristicse.g. size distribution, chemistry etc.
TESTING PROCEDURES: EXEMPLARY EVALUATION
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 8
Reference Electrometer Device under Test (CPC)
Raw Concentration 8255/cm³ 6904/cm³
Zero Offset 116/cm³ 0/cm³
Nominal Flow : measured Flow 3 l/min : 2,87 l/min 1 l/min : 1,01 l/min
Flow correction 1,045 0,99
Flow corrected concentration 8629/cm³ 6836/cm³
Flow corr. concentration @59nm 3170/cm³ 2864/cm³
Double charge ratio (Theory) 5,7% 5,7%
Double charged particles 181/cm³ 163/cm³
Double Charge Correction 8629-2*181 6836-163
Charge corrected concentration 8267/cm³ 6673/cm³
CPC Counting Efficiency 6673 : 8267 = 80,7%
Example: Calibration at 41nm
TESTING PROCEDURES: LINEARITY
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 9
Target ConcentrationReference Device
0 1.000 2.000 4.000 6.000 8.000 10.000
Linearity Measurement & Linear Fit
y = 0,84x + 17,73R² = 1,00
0
2000
4000
6000
8000
10000
12000
0 2000 4000 6000 8000 10000 12000
Test
Dev
ice
Co
nce
ntr
atio
n [
1/c
m³]
Reference Concentration [1/cm³]
Grimm Engine Exhaust CPC
Linear (Grimm Engine Exhaust CPC)
Reference Device: Aerosol Electrometer or CPC
PossiblyElectrometer offset
Extra Engine Exhaust CPC
Linear Fit
TESTING PROCEDURES: COUNTING EFFICIENCY
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 10
Measurement
• Recording uncorrected Raw Data
• No K-factor on devices under test
• 70nm mobility diameter
• Averaging time: 60-240 seconds
Flow
• Correction: Nominal / actual flow
• Flow measurement: Volume or Mass
Charges
• Correction for double charges
• Charge distribution: Wiedensohler
• Derived from Counting Efficiency test
Splitter Bias: Only corrected in certain labsrequired in ISO 27891
Electrometer Zero: Not correctedTo be applied in the future?
Critical when using reference Electrometer
Influenced by:Aerosol Characteristicse.g. size distribution, chemistry etc.
SOOT GENERATORS: SIZE RANGE
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 11
0
5000
10000
15000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Mobility Diameter [nm]
0
1000
2000
3000
4000
5000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Mobility Diameter [nm]
0
10000
20000
30000
40000
50000
Part
icle
Co
nce
ntr
atio
n [
1/c
m³] miniCAST 6204C at BMW
Round Robin APG w miniCAST 6203C
PALAS DNP 3000 with N2
SOOT GENERATORS: SIZE RANGE
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 12
0
5000
10000
15000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Mobility Diameter [nm]
0
1000
2000
3000
4000
5000
10 100Pa
rtic
le C
on
cen
trat
ion
[1
/cm
³]
Mobility Diameter [nm]
0
10000
20000
30000
40000
50000
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
PALAS DNP 3000 with N2
Round Robin APG w miniCAST 6203C
miniCAST 6204C at BMW
SOOT GENERATORS: MAXIMUM CONCENTRATION COMPARISON @10NM
EXAMPLE: Maximum Concentration at BMW laboratory setup (sampling volume, 15l/min dilution air)
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 13
On-site miniCAST AVL Particle Generator PALAS DNP 3000
GMD Max. Conc. GMD Max. Conc. GMD Max. Conc.
10nmVery small 2500/cm³ Very small 35/cm³
Small 1300/cm³ Small 600/cm³ Small 200/cm³
Medium 400/cm³ Medium 180/cm³ Medium 250/cm³
15nm
Very small 1700/cm³ Very small 25/cm³
Small 7900/cm³ Small 1020/cm³ Small 700/cm³
Medium 1700/cm³ Medium 1200/cm³ Medium 2000/cm³
10nm: Insufficient concentration for calibration vs. electrometer with example setup
Going to larger sizes (GMD 20nm – 30nm): No need to worry about multiple charges?
SOOT GENERATORS: CAST – INTERCHANGING SETTINGS
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 14
0
1000
2000
3000
4000
5000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Mobility Diameter [nm]
Round Robin APG w miniCAST 6203C
0
10000
20000
30000
40000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Mobility Diameter [nm]
miniCAST 6204C with APG burner settings
CAST-settings are not transferable between models!
SOOT GENERATORS: CAST – SINGLE SIZE DISTRIBUTION CALIBRATION
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 15
0%
20%
40%
60%
80%
100%
120%
10 100
Co
un
tin
g Ef
fici
ency
Mobility Diameter
Reference Electrometer
GMD 20nm
GMD 35nm
GMD 50nm
0
10000
20000
30000
40000
50000
10 100
Part
icle
Co
nce
ntr
atio
n [
1/c
m³]
Electrometer OffsetVery low absolute concentration
Size distribution influenceWith double charge correction applied
Especially when comparing Electrometer & CPC
Calibration Aerosols
CPC CALIBRATION ROUND ROBINFIRST FINDINGS
Participants from all areas of the engine exhaust PN –community
Measurements examine CAST soot as a calibration aerosol
Possible concentration issues for sub-23nm calibration
No universal burner settings for different CAST models
Size distribution influences measurement results
Terres: CPC Calibration Round Robin | Calibration Aerosols and Laboratory Setups | 2016-10-12 Page 16
A big “Thank You” to all the labs that are contributing to this Round Robin!
Open questions for calibration with CAST soot
(only partly covered in ISO 27891):
Clear definition of suitable size distributions
Accurate correction for multiple charges / Strategies to avoid multiple charges
Zero correction and Zero drift of Electrometers
Suitability of „Sample volume-type“ test setup for calibration