Post on 04-Nov-2020
Correlation between Pegasor Particle Sensor and Particle Number Counter Application of Pegasor Particle Sensor in Heavy Duty Exhaust
Dr. Harald Beck, Dr. Dieter Rothe, Christian Tyroller
MAN Truck & Bus AG, Nuremberg, Germany
Harald.beck@man.eu
The implementation of a particle number limit by Euro VI has lead to the development of an “appropriate” measurement method. This method affords the sampling from diluted engine exhaust and the usage of a complex sample treatment before measurement in a particle number counter. The commercial setups are cost intensive and more over bulky. For engine development another measurement system should be found. In the following studies a new in line sensor, developed by Pegasor was used in comparison with an AVL APC Advanced and an AVL Micro Soot Sensor.The studies have been performed in order to find similarities between the sensor signals. The tests were carried out with a heavy duty diesel EURO IV engine equipped with a continuously regenerating particle trap.
D2066 LF 31 Euro 4Number of cylinder: 6Displacement: 10.5l Power: 440 PSTorque: 2100 Nm
AVL APC 489
AVL MSS 483
Pegasor ParticleSensor(Preversion)
DPFD2066 LF 31 Euro 4Number of cylinder: 6Displacement: 10.5l Power: 440 PSTorque: 2100 Nm
AVL APC 489
AVL MSS 483
Pegasor ParticleSensor(Preversion)
DPF
Figure 1: Schematic test setup. The signal correlation has been investigated during several European Stationary and European Transient Cycles before and behind the particle trap.
29.09.201111:21:13_2023 990 mbar 0 %
P
egas
or
[mV
]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
REK_1HZ.TIME [s]
240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800
A
PC
[P
/cm
³]
0.0·100
1.0·107
2.0·107
3.0·107
4.0·107
5.0·107
M
SS
[m
g/m
3]
0
10
20
30
40
29.09.201111:21:13_2023 990 mbar 0 %
P
egas
or
[mV
]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
REK_1HZ.TIME [s]
240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800
A
PC
[P
/cm
³]
0.0·100
1.0·107
2.0·107
3.0·107
4.0·107
5.0·107
M
SS
[m
g/m
3]
0
10
20
30
40
29.09.201111:21:13_2023 990 mbar 0 %
P
egas
or
[mV
]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
REK_1HZ.TIME [s]
240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800
A
PC
[P
/cm
³]
0.0·100
1.0·107
2.0·107
3.0·107
4.0·107
5.0·107
M
SS
[m
g/m
3]
0
10
20
30
40
Figure 2: Signal of PPS, MSS and APC during a transient test cycle.
In transient tests the sensor showed a fast response time. The correlation of Pegasor signal to soot mass signal was found to be moderate, the correlation to particle number concentration was found to be good.
11.08.201111:33:34_1958 979 mbar 0 %
P
eg
aso
r [m
V]
Inte
gra
l: P
eg
aso
r [m
V]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
REK_1HZ.TIME [s]0 500 1000 1500 2000
Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,Pegasor)) = 178843
A
PC
[P
/cm
³]
0.0·100
5.0·106
1.0·107
1.5·107
2.0·107
2.5·107
3.0·107
3.5·107
4.0·107
4.5·107
5.0·107
Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,APCxDR_U)) = 8.79783e+09
Inte
gra
l :
AP
C [
P/c
m³]
0·100
1·109
2·109
3·109
4·109
5·109
6·109
7·109
8·109
9·109
0·100
2·104
4·104
6·104
8·104
1·105
1·105
1·105
2·105
2·105
Figure 3: Correlation of PPS to APC during a European Test Cycle. During the tests the Pegasor Particle Sensor showed a good signal correlation to MSS and APC. The signals were found to be reproducible. Moreover the sensor proved itself to be stable and robust und heavy duty diesel engine conditions.
Correlation between Pegasor Particle Sensor and Particle Number Counter
Application of Pegasor Particle Sensor in Heavy Duty exhaust
Dr. Harald Beck, Dr. Dieter Rothe, Christian Tyroller
16th ETH Conference on Combustion Generated Nanoparticles,
June 24th – 27th 2012
Zurich ETH Zentrum, Main Building, HG E7
2< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
1
3< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
1 Motivation
For EURO VI Homologation particle emission limits have to be fulfilled:
PN: 6 ·1011 # kW h-1 (WHTC) and 8·1011 # kW h-1 (WHSC)
PM: 10 mg kWh-1
The proposed setup according to UN ECE Regulation 49 is bulky and cost intensive (Invest and life cycle cost)
Particle number concentration measurement according to UN ECE Regulation 49 has an impact on particle mass measurement with partial dilution systems
Demands from engineers for an alternative system:
Its signal should correlate with certification standard system
It should be able to measure transient cycles
It should be small and robust (raw exhaust application)
It shall need little service effort (Cost effect in invest and life cycle),
Easy operation (plug and play) should be ensured
4< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
2
5< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
2 Peagasor Particle Sensor (1/3)(Sensor Layout)
dilution air
6< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
2 Pegasor Particle Sensor (2/3)(Operating principle)
Chargerpower
Electrometer
In = Iout - Iin
Iin
Iout
Sample in
Sample out
Isolated power transfer
Faraday cup
Aerosol charging
In
Technique referred to as “Escaping Current”
7< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
2 Peagasor Particle Sensor (3/3)(Sensor Physical Dimensions)
Main Features• Compact design, installed directly to the tailpipe• Particles are not collected• Sensitive parts protected from exhaust flow => Low maintenance• High resolution and sensitivity (10 Hz, 0.3sec Response Time)
Inlet
Outlet
Carrier air
8< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
3
9< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
3 Experimental Setup (1/3)(Schematic Overview)
D2066 LF 31 Euro 4Number of cylinder: 6Displacement: 10.5l Power: 440 PSTorque: 2100 Nm
AVL APC 489
AVL MSS 483
Pegasor ParticleSensor(Preversion)
DPF
10< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Experimental Setup (2/3)(Test cell)
MSS
APC
PegasorEngine
11< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Experimental Setup (3/3)(Test programme)
Investigation topics:
Influence of dilution air pressure on the PPS signal
Signal correlation of PPS vs APC and MSS in stationary test cycle (ESC)
Signal correlation of PPS vs APC and MSS in transient test cycle (ETC)
Correlation in raw exhaust and after diesel particulate filter
12< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
4
13< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
4 Influence of dilution air pressure (1/4)(Test programme)
23.09.201109:47:53_2006 983 mbar 42% Pegasor
P
PS
-Lu
ftd
ruck
[m
bar
]
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
Zeit11:00:00 11:20:00 11:40:00 12:00:00 12:20:00 12:40:00 13:00:00 13:20:00 13:40:00 14:00:00
M
[N
m]
400
600
800
1000
1200
1400
N
[U
/min
]
1100
1200
1300
1400
1500
1600
Air
pre
ssu
re
time
engi
ne s
peed
torq
ue
14< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
4 Influence of dilution air pressure (2/4)(Signal sequence)
31.08.201115:19:16_1990 977 mbar 39% Pegasor
P
egas
or
[mV
]
0
50
100
150
200
250
300
350
400
450
500
550
600
Zeit
15:20:00 15:40:00 16:00:00 16:20:00 16:40:00 17:00:00 17:20:00 17:40:00 18:00:00
A
PC
[P
/cm
³]
0
5000000
10000000
15000000
20000000
25000000
30000000
M
SS
[m
g/m
³]
0
5
10
15
20
25
time
15< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
4 Influence of dilution air pressure (3/4)(PPS vs. MSS)
y = 0,0106x + 6,5155
R2 = 0,9961
y = 0,013x + 7,1543
R2 = 0,9997
y = 0,0065x + 18,811
R2 = 0,955
0
5
10
15
20
25
30
35
40
0 500 1000 1500 2000 2500
Druck [mbar]
PP
S/M
SS
[m
V/(
mg
/m3 )]
M1 M2 M3
Air pressure
16< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
4 Influence of dilution air pressure (4/4)(PPS vs. APC)
y = 6E-09x + 3E-06
R2 = 0,9935
y = 8E-09x + 4E-06
R2 = 0,9982
y = 5E-09x + 1E-05
R2 = 0,9838
0,00E+00
5,00E-06
1,00E-05
1,50E-05
2,00E-05
2,50E-05
0 500 1000 1500 2000 2500
Druck [mbar]
PP
S/A
PC
[m
V/(
1/c
m3 )]
M1 M2 M3
Air pressure
17< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
5
18< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (1/7)(Test programme)
10.06.201109:43:01_1832 979 mbar 42%
N
[U
/min
]
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
Zeit09:00:00 10:00:00 11:00:00 12:00:00 13:00:00 14:00:00 15:00:00 16:00:00
M
[N
m]
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
time
19< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (2/7)(PPS vs. MSS raw exhaust)
20.06.201110:37:03_1848 979 mbar 0 %
M
SS
[m
g/m
³]
0
5
10
15
20
25
30
35
40
Pegasor [mV]0 100 200 300 400 500 600
20110620-173221_d2066lf31_tl_1848.b01.utx.nc (Pegasor,MSSxDR_U):correlation = 0.967702
20110620-173221_d2066lf31_tl_1848.b01.utx.nc (Pegasor,MSSxDR_U):Minimum.............: -0.011Maximum.............: 35.619arith. Mittelwert...: 5.25385Mittlere Abweichung.: 4.90956Varianz.............: 32.9519Standard-Abweichung.: 5.74037
Polynom-Ordnung 1: f(x) = p0 + p1*x + ...
p0 = 0.571968006025839p1 = 0.0452921444458772
R=0.97
20< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (3/7)(PPS vs. APC raw exhaust)
20.06.201110:37:03_1848 979 mbar 0 %
A
PC
[P
/cm
³]
0.0·100
5.0·106
1.0·107
1.5·107
2.0·107
2.5·107
Pegasor [mV]0 100 200 300 400 500 600
20110620-173221_d2066lf31_tl_1848.b01.utx.nc (Pegasor,APCxDR_U):correlation = 0.979386
20110620-173221_d2066lf31_tl_1848.b01.utx.nc (Pegasor,APCxDR_U):Minimum.............: -4Maximum.............: 2.34e+07arith. Mittelwert...: 4.01487e+06Mittlere Abweichung.: 3.67198e+06Varianz.............: 2.16706e+13Standard-Abweichung.: 4.65517e+06
Polynom-Ordnung 1: f(x) = p0 + p1*x + ...
p0 = 172239.323181636p1 = 37173.2869668173
R=0.98
21< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (4/7)(PPS vs. MSS post DPF)
10.06.201109:43:01_1832 969 mbar 0 %
M
SS
[m
g/m
³]
0.0
0.5
1.0
1.5
2.0
Pegasor [mV]0 5 10 15 20 25 30 35 40 45 50
20110610-153618_d2066lf31_tl_1832.b01.utx.nc (Pegasor,MSSxDR_U):correlation = 0.830476
20110610-153618_d2066lf31_tl_1832.b01.utx.nc (Pegasor,MSSxDR_U):Minimum.............: 0.039Maximum.............: 2.344arith. Mittelwert...: 0.285282Mittlere Abweichung.: 0.146267Varianz.............: 0.040331Standard-Abweichung.: 0.200826
Polynom-Ordnung 1: f(x) = p0 + p1*x + ...
p0 = 0.120228200820071p1 = 0.0255076499057002
R=0.83
22< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (5/7)(PPS vs. APC post DPF)
10.06.201109:43:01_1832 969 mbar 0 %
A
PC
[P
/cm
³]
0.0·100
5.0·105
1.0·106
1.5·106
2.0·106
2.5·106
Pegasor [mV]0 5 10 15 20 25 30 35 40 45 50
Polynom-Ordnung 1: f(x) = p0 + p1*x + ...
p0 = -19063.6623004908p1 = 57961.1049093845
20110610-153618_d2066lf31_tl_1832.b01.utx.nc (Pegasor,APCxDR_U):correlation = 0.974596
20110610-153618_d2066lf31_tl_1832.b01.utx.nc (Pegasor,APCxDR_U):Minimum.............: 17900Maximum.............: 2.06e+06arith. Mittelwert...: 355988Mittlere Abweichung.: 314468Varianz.............: 1.51209e+11Standard-Abweichung.: 388856
R=0.97
23< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (6/7)(PPS vs. MSS)
y = 0,0255x + 0,1202
y = 0,0354x + 0,3461
y = 0,0453x + 0,572
0
0,5
1
1,5
2
2,5
3
0 5 10 15 20 25 30 35 40 45 50
Pegasor [mV]
MS
S [
mg
/m3
]
Rohabgas nach DPF Ausgleichsgeraderaw exhaust post DPF Intermediate
24< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
5 Correlation Stationary tests (7/7)(PPS vs. APC)
y = 57961x - 19064
y = 47567x + 76588
y = 37173x + 172239
0,0E+00
5,0E+05
1,0E+06
1,5E+06
2,0E+06
2,5E+06
3,0E+06
3,5E+06
0 5 10 15 20 25 30 35 40 45 50
Pegasor [mV]
AP
C [
P/c
m3
]
Rohabgas nach DPF Ausgleichsgeraderaw exhaust post DPF Intermediate
25< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Agenda
1 Motivation
2 Pegasor Particle Sensor
3 Test setup and Programme
4 Pretest results
5 Stationary Tests and Results
6 Transient Tests and Results
7 Conclusion
6
26< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
6 Transient test signal (1/5) (PPS vs. MSS raw exhaust)
29.09.201111:21:13_2023 990 mbar 0 %
P
egas
or
[mV
]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
REK_1HZ.TIME [s]
240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800
A
PC
[P
/cm
³]
0.0·100
1.0·107
2.0·107
3.0·107
4.0·107
5.0·107
M
SS
[m
g/m
3]
0
10
20
30
40
27< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
6 Correlation Transient tests (2/5)(PPS vs. MSS raw exhaust)
11.08.201111:33:34_1958 979 mbar 0 %
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
REK_1HZ.TIME [s]0 500 1000 1500 2000
Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,Pegasor)) = 178843
M
SS
[m
g/m
3]
0
20
40
60
80
100
120
140Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,MSSxDR_U)) = 8589.6
Pe
ga
sor
[mV
]In
teg
ral :
P
eg
aso
r [m
V]
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
Inte
gra
l :
MS
S [
mg
/m3
]
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
28< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
6 Correlation Transient tests (3/5)(PPS vs. APC)
11.08.201111:33:34_1958 979 mbar 0 %
P
eg
aso
r [m
V]
Inte
gra
l: P
eg
aso
r [m
V]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
REK_1HZ.TIME [s]0 500 1000 1500 2000
Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,Pegasor)) = 178843
A
PC
[P
/cm
³]
0.0·100
5.0·106
1.0·107
1.5·107
2.0·107
2.5·107
3.0·107
3.5·107
4.0·107
4.5·107
5.0·107
Integral(20110811-120958_d2066lf31_etc_1958.b01.utx.nc (REK_1HZ_TIME,APCxDR_U)) = 8.79783e+09
Inte
gra
l :
AP
C [
P/c
m³]
0·100
1·109
2·109
3·109
4·109
5·109
6·109
7·109
8·109
9·109
0·100
2·104
4·104
6·104
8·104
1·105
1·105
1·105
2·105
2·105
29< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
6 Correlation Transient tests (4/5)(PPS vs. APC average 6 ETC)
-40
-30
-20
-10
0
10
20
30
Ab
we
ich
un
g [
%]
Rohabgasformel Ausgleichsformel "nach DPF"-Formel
Rohabgasformel -19,83 -22,18
Ausgleichsformel -0,80 -8,35
"nach DPF"-Formel 18,22 5,49
Messung im Rohabgas Messung nach DPF
Dev
iatio
n
Raw exhaust measurement Measurement after DPF
Raw exhaust
Intermediate
post DPF
Raw exhaust post DPFIntermediate
30< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
6 Correlation Transient tests (5/5)(PPS vs. MSS average of 6 ETC)
-60
-50
-40
-30
-20
-10
0
10
20
30
40
Ab
we
ich
un
g [
%]
Rohabgasformel Ausgleichsformel "nach DPF"-Formel
Rohabgasformel 0,65 27,19
Ausgleichsformel -23,61 -6,80
"nach DPF"-Formel -47,86 -40,79
Messung im Rohabgas Messung nach DPF
Raw exhaust Intermediate post DPF
Raw exhaust measurement Measurement after DPF
Raw exhaust
Intermediate
post DPF
Dev
iatio
n
31< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
7 Conclusion
Pegasor Particle Sensor (PPS) was tested under heavy duty real world conditions.
In transient tests the sensor proofed a fast response time
With constant dilution air pressure results were found reproducible
(For traceability reasons an additional pressure recording is recommended)
Under partial load stationary conditions good correlation were found for raw exhaust measurements MSS- (>96%) and APC-Signal (>98%) and for measurements after DPF MSS- (>83%) and APC-Signal (>97%)
The correlation equation found under partial load condition were applied on ESC and ETC. The calculated results lead to deviations of less than 10 % compared with reference analytics.
32< >MAN Truck & Bus AG Dr. Harald Beck 16th ETH Conference on Combustion Generated Nanoparticles 26.06.2012EMFA
Time for Questions
Dr. Harald Beck
MAN Truck & Bus AG
EMFA
Vogelweiherstrasse 33
90441 Nürnberg
Tel. +49-911-420-1530
harald.beck@man.eu
Dr. Dieter Rothe
MAN Truck & Bus AG
EMRE
Vogelweiherstrasse 33
90441 Nürnberg
Tel. +49-911-420-2061
dieter.rothe@man.eu
Christian Tyroller
MAN Truck & Bus AG
EMRE
Vogelweiherstrasse 33
90441 Nürnberg
Tel. +49-911-420-6597
christian.tyroller@man.eu
The authors would like to thank:Juha Tikkanen (Peagasor) Thomas Hamacher (MS4)for the technical support.