Measurement of the Instantaneous In-Cylinder Soot Temperature … · 2016. 4. 13. · Zylinderdruck [bar] Zyl. 1 Zyl. 2 Zyl. 4 0 5 10 15 20 0 0.5 1 1.5 2 2.5 x 10-8 Betriebspunkt

11th ETH Conference on Combustion Generated Nanoparticles 15.08.2007 Kirchen et al.

Measurement of the Instantaneous In-Cylinder Soot Temperature and Concentration in a Multi-

Cylinder Engine

Patrick KirchenStefan WaltherPeter ObrechtKonstantinos Boulouchos

Aerothermochemistry and Combustion Systems Laboratory ETH Zürich

Dieter KarstClaudio Cavalloni

Kistler Instruments AG

Sensoptic


OVERVIEW

Overview of instrumentation and measurements

Selection and evaluation of a suitable correlation between FSN and Pyrometry

Use of the correlation to investigate cycle to cycle soot emission variations

Investigation of soot formation and oxidation processes

GOALS: Correlation between in-cylinder and engine-out soot emissionsCharacterize cylinder and cycle specific soot emissions in a multi - cylinder engine


INTRODUCTION SOOT INSTRUMENTATION

In-cylinder measurement of soot formation and oxidation processesLight radiated from soot is used to determine:

Soot temperatureKL-Factor (~ soot concentration)

Considers only hot (glowing) soot

PyrometryMeasurement of the steady-state, engine-out soot emissions (in exhaust system)Extracted exhaust is drawn through filter paper – paper blackening is measured A measure of all particulate components

FSN

GOALS: Correlation between in-cylinder and engine-out soot emissionsCharacterize cylinder and cycle specific soot emissions in a multi - cylinder engine


MEASUREMENTS TESTBENCH/INSTRUMENTATION

VW TDI, 4 cyl. (Kistler)Soot instrumentation

In-cylinder 3 color pyrometry (KL-factor)Exhaust mounted AVL 415S (FSN)

Additional parametersCylinder pressure (cylinders 1, 2, 4)Intake air pressure (1 Sensor)Air mass flow rate (venturi)Exhaust CO2 concentration for λ


1000 1500 2000 2500 3000 3500 40002

4

6

8

10

12

14

16

18

Engine Speed [min-1]

Engi

ne L

oad,

IM

EP [

bar]

MEASUREMENTS OPERATING POINTS

20 steady state operating points from the entire map

Wide soot emission range: FSN = 0.4 … 4.1

Reference point

Cylinders 1, 2, 4 with 3 color pyrometry und cylinder pressure

Reference point repeated 4x


3 COLOR PYROMETRY IMPLEMENTED SENSOR

System developed by:

Kistler AGLAV (ETH Zürich)Sensoptic

Uses 3 wavelengths for redundancy

Window heated to 600°C to prevent contamination

Small size permits use in production engines (glowplugadapter, for eg.)

dSensor = 3mm


3 COLOR PYROMETRY OVERVIEW

Kalibration


KL-FACTOR TYPICAL FEATURES

350 400 4500

5

10

15

x 10-10

Kurbelwinkel [°KW nGWOTP]

KL

Fakt

or [

m1

.39 ]

350 400 4500

0.5

1

1.5

2

x 10-9


KL

Fakt

or [

m1

.39 ]

Characteristics of the KL-factor that can potentially be correlated to FSN

Maximum KL-factor value1st plateau2nd plateau (KLend)

0.910.890.880.872. Plateau

0.840.91 0.800.791. Plateau

All Cyl.Cyl. 4Cyl. 2Cyl. 1R2

CORRELATION OF KL VALUES WITH FSN OVER ALL POINTS


0 1 2 3 4 50.5

1

1.5

2

2.5

3

3.5

4x 10

-8

FSN [-]

KL

Fact

or [

m1

.39]

R2 = 0.91

KL-FSN CORRELATION COMPARISON

Maximum KL-Factor value – no correlation with FSNInvestigation of the correlation between 1st and 2nd plateau and FSNCorrelations using cylinder specific and summed KL factor valuesBest correlation with the summed KL factors from all cylinders

0.910.890.880.872. Plateau

0.840.91 0.800.791. Plateau

All Cyl.Cyl. 4Cyl. 2Cyl. 1R2


FSN and KL COMPARISON


Engi

ne L

oad,

IM

EP [

bar]

1500 2000 2500 3000 35004

6

8

10

12

14

16

0.5

1

1.5

2

2.5

3

3.5


Engi

ne L

oad,

IM

EP [

bar]

1500 2000 2500 3000 35004

6

8

10

12

14

16

1

1.5

2

2.5

3

3.5x 10

-8

Pyrometry(KLEND)FSN

Time averaged, engine-out soot emissionsQualitative soot emission tendencies are reproduced by both methods


KLEND VALUES CYLINDER SPECIFIC CONSIDERATIONS

Cylinder 2:KLend is an order of magnitude higher than other cylindersNon-perpendicular sensor installationAdditional sensor access (lower compression ratio)

Combustion and KL-factors in cylinders 1 and 4 are similar

340 350 360 370 380 39035

40

45

50


Zylin

derd

ruck

[ba

r]

Zyl. 1Zyl. 2Zyl. 4

0 5 10 15 200

0.5

1

1.5

2

2.5x 10

-8

Betriebspunkt [-]

KL

Fakt

or E

ndw

ert

(2. P

late

au)

[m1.

39]

Zyl. 1Zyl. 2Zyl. 4

Cyl. 4 Cyl. 3 Cyl. 2 Cyl. 1

n=2000 [min-1]; IMEP=4.0 [bar]


CYCLE TO CYCLE VARIATIONS

KL history comapred for 144 consecutive operating cycles during steady state operation (ne = 2500 [min-1], IMEP = 16 [bar])Soot formation process ~const.Soot oxidation higher variability

350 360 370 380 390 400 410

0

2

4

x 10-9

Crank Angle [CAD aGETDC]

KL

Fact

or [

m-1

.39 ]

350 360 370 380 390 400 410

0

1000

2000

Soot

Tem

pera

ture

[K

]


Engi

ne L

oad,

IM

EP [

bar]

σ(KLend)

1500 2000 2500 3000 35004

6

8

10

12

14

16

0.12

0.14

0.16

0.18

0.2

0.22

0.24



Engi

ne L

oad,

IM

EP [

bar]

1500 2000 2500 3000 35004

6

8

10

12

14

16

0.6

0.65

0.7

0.75

0.8

0.85

KLMAX AND KLEND SOOT FORMATION AND OXIDATION

KLmax -> maximum soot concentrationKLend -> soot quantity after oxidation


Engi

ne L

oad,

IM

EP [

bar]

1500 2000 2500 3000 35004

6

8

10

12

14

16

KL

Fact

or m

ax [

m1

.39]

1.5

2

2.5

3

3.5

4

4.5

x 10-9

More soot formed at higher loads (NOT the same as engine out)

Oxidized soot fraction strongly influenced by operating point…


1500 2000 2500 3000 35000

1

2

3

4

5x 10

-9

KL-

Fact

or [

m1

.39]

1500 2000 2500 3000 3500

0.70.750.80.850.90.95

Oxi

dize

d So

ot F

ract

ion,

Δ K

L [-

]

Engine Speed, ne [min-1]

KLmax

KLend

Δ KL

KLMAX AND KLEND LOAD AND SPEED VARIATIONS

IMEP = 12 [bar], ~const KLmax

4 6 8 10 12 14 160

5

x 10-9

KL-

Fact

or [

m1

.39]

4 6 8 10 12 14 16

0.6

0.8

Oxi

dize

d So

ot F

ract

ion,

Δ K

L [-

]

Engine Load, IMEP [bar]

KLmax

KLend

Δ KL

ne=2000 [min-1], KLmax increasing

TemperatureTime available for oxidation

Oxidation influenced by:Turbulence (ne, pinj)Oxygen concentration (EGR, λ)


CONCLUSIONS / SUMMARY

Engine out and in-cylinder soot emissions from a production, multi-cylinder engine were measured using FSN and 3 color pyrometryThe KLend value provides a measure of the cylinder and cycle specific cylinder out soot emissionsFSN correlates well to the sum of the average cylinder specific KLendvaluesCylinder out soot emissions are defined by:

Soot formed (~injected fuel quantity)Soot oxidized:

TurbulenceOxygen availabilityTemperature

Fluctuations in KLend values during steady state operation are predominantly due to fluctuations in the oxidation process


THANK YOU FOR YOUR ATTENTION!

Measurement of the Instantaneous In-Cylinder Soot Temperature … · 2016. 4. 13. · Zylinderdruck [bar] Zyl. 1 Zyl. 2 Zyl. 4 0 5 10 15 20 0 0.5 1 1.5 2 2.5 x 10-8 Betriebspunkt

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