cvut-jbrc scope

INGAS 6 months Meeting, Prague, 25-26 May, 2009INGAS 6 months Meeting, Prague, 25-26 May, 2009

INGAS INtegrated GAS PowertrainINGAS INtegrated GAS Powertrain

1

CVUT-JBRC Scope

Experimental Facilities – General Features – InGAS Customizing Simulation Facilities – Overview of Engine Models Layout – InGAS usability

EF (WPB0.4) – Calibration DataBasic AdjustmentInitial Evaluation of Fuel Blend Behavior

SF (WPB0.2) - In-house Model OBEH Recalculation of HR PatternsGT-Power Model Tuning2-zone Approach – Knock Tendency Description



2

CVUT-JBRC Experimental Facilities

Engine Features:Compression Ratio: 12Up to 20 bar BMEPBoost pressure up to 1.4 barg

4102/120 Testing Engine

= 1 (Closed Loop) or Lean BurnVGTCooled EGR up to 20 %

Test Bench Equipment: DC DynamometerComplete DAQGas Analyzers – Exhaust / IntakeTPA (Cylinder, Turbine – Inlet/Outlet)Instantaneous Speed – Engine, Turbo Knock Recognition/Quantification



3

CVUT-JBRC Experimental Facilities

Additional Fuel A

Additional Fuel B

TNG

SetPoint

Feedback

Test BenchComputer

On-line Controllable Delivery of Max. of 2 Fuel Additives into Intake Manifold



4

CVUT-JBRC Experimental Facilities4 102/110 Engine

Engine features:Compression Ratio: 10Low BMEPLow Boost PressureUncontrolled Turbocharger= 1 (Closed Loop) or Lean BurnNo EGR

Experimental Equipment:AC (W-E) Dynamometer (No Closed

Loop Control)Complete DAQTPA (Intake/Cylinder/Exhaust “Close to

Cylinder” Arrangement)Controllable Delivery of Fuel Additives(Sampling of Working Substance from

Cylinder during Compression Stroke)

Appropriate for: Emulation of “Low Cost” Version;“Steady State” Knock;Preliminary Testing;



5

CVUT-JBRC Simulation Means

OBEH (= CYCLE) – In-House Engine Working Cycle Model Source Code Written in FORTRAN (DOS Based)

0-D

Description of Working Substance Behavior Inside the Cylinder by Differential Equations

Description of Engine Manifold and Accessory (Including Turbo) by Algebraic Equation

Inertia of Gas Bulk Flows NOT Involved

Basics:HR Description by Vibe’s Function

Czallner – Woschni Recalculation FormulasHeat Transfer Selectable Woschni’s and/or Eichelberg’s

Dedicated Among Other for Use in Education Activities

Supplements:Temperature of Unburned Zone & Ignition LagAutomated Tuning/Optimization – Pre & Post Processing (Excel-Based) In-House HR Recalculation Routine



6


GT-Power – Commercial Engine Model (JBRC = Official Partner of Gamma Technologies)

Version: 6.2

1-D

Engine(s) Geometry Imposed According to Physical Reality

102/120 Engine => Turbine & Compressor Maps Obtained from TC Manufacturer

Calibration Data:Set of Engine Integrated ParametersAngle-Resolved Patterns of:

In-Cylinder PressureManifold Pressure Turbo Speed



7


Knock Recognition/Quantification Routine

Experimental Data0

20

40

60

80

100

120

140

-100 -50 0 50 100

Crank angle [deg]

Cy

lin

de

r p

res

su

re [

ba

r]

0

500

1000

1500

2000

2500

3000

3500

4000

Me

an

in

-cy

lin

de

r te

mp

era

ture

[K

]

In-cylinder pressuremeasuredIn-cylinder pressurecalculatedMean in-cylindertemperature experimentMean in-cylindertemperature calculated

Model Calibration

0

500

1000

1500

2000

2500

-100 -50 0 50 100

Crank angle [deg]

Tcy

l, T

un

b [

K]

0

0.2

0.4

0.6

0.8

1

1.2

exh

aust

ed

ign

itio

n d

ela

y [1

]

Tcyl

Tunb

exhausted ignition delay

Knock Evaluation

Experimental Verification



8

CVUT-JBRC Full Load Curve ProposalBoost Pressure Adjustement

0

20

40

60

80

100

120

140

160

180

1200 1400 1600 1800 2000 2200 2400 2600 2800

Engine Speed [1/min]

Throttle Position 0=IDLE, 160=WOT

VGT Rack 0=max A_nozzle, 80=min A_nozzle

Boost Pressure [kPag]

Exhaust Back Pressure [kPag]

Turbo Speed [1000/min]



9

CVUT-JBRC Full Load Curve ProposalIgnition Timing & EGR Adjustement

0

5

10

15

20

25

30

1200 1400 1600 1800 2000 2200 2400 2600 2800


Ign

.Tim

ing

, K

no

ck I

nte

nsi

ty,

EG

R

400

450

500

550

600

650

700

750

800

850

Exh

aust

Tem

per

atu

re

Ignition Timing [deg CA bTDC]

Knock Intensity, 0=Knock-Free, 5=Heavy Knock

EGR rate [%]

Exhaust Temperature Upstream of the Turbine [°C]

Exhaust Temperature Downstream of the Turbine [°C]



10

CVUT-JBRC Full Load Curve Proposal

-20

0

20

40

60

80

100

120

140

1200 1400 1600 1800 2000 2200 2400 2600 2800


Cra

nkA

ng

le [

deg

CA

], p

MA

X [

bar

a]

2150

2200

2250

2300

2350

2400

2450

2500

TM

AX

[K

]

10% burnt [deg CA aTDC]



Peak Pressure [bara]

Peak Pressure Position [deg CA °aTDC]

Peak Temperature [K]



11

CVUT-JBRC Full Load Curve Proposal

400

600

800

1000

1200

1400

1600

1800

2000

2200

900 1100 1300 1500 1700 1900 2100 2300 2500 2700 2900

eRPM [/min]

bm

ep [

kPa]

9.4

9.6

9.8

10

10.2

10.4

10.6

10.8

11

bsh

c [M

J/kW

h]

bmep VGT (Final) [kPa]

bmep WG (Previous) [kPa]

bmep Diesel [kPa]

bshc VGT (Final) [MJ/kWh]

bshc Diesel [MJ/kWh]



12

CVUT-JBRC Full Load Curve WG -- VGT

-5

0

5

10

15

20

25

30

35

1200 1400 1600 1800 2000 2200 2400 2600 2800


Cra

nkA

ng

le [

de

g C

A]

680

700

720

740

760

780

800

820

840

860

tEX

HA

US

T [

°C]




AKR 0=Knock Free, 5=Heavy Knock

Exhaust Temperature

Original - WG Improved - VGT



13

CVUT-JBRC -control Adjustment

80

90

100

110

120

130

140

0 10 20 30 40 50 60

Actuator Pos 0=min A_fuel, 255=max A_fuel

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50 60time [s]

Lambda Sensor Voltage [V]

0.8

0.9

1

1.1

1.2

1.3

0 10 20 30 40 50 60

Torque [% fluctuation]Fuel Flow [% fluctuation]

bmep=1.8 barbmep=10 bar



14

CVUT-JBRC CO2 Addition – Initial EvaluationValues Averaged from 80 Acquired Cycles in Each Operating Point

-10

10

30

50

70

90

110

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

vAf [m3CO2/m3(CO2+TNG)]

CA

xx

[°C

A],

pM

AX

[b

ar]

1000

1200

1400

1600

1800

2000

2200

2400

2600

TM

AX

[K

]

CA2 CA5 CA50 CA90

CA95 pMAX TMAX



15

CVUT-JBRC CO2 Addition – Initial EvaluationCycle-to-Cycle Variablity

-10

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80

Cycle #

CA

xx

[°C

A]

noCO2al2

noCO2al5

noCO2al95

37%CO2_al2

37%CO2_al5

37%CO2_al95



16

CVUT-JBRC CO2 Addition – Initial Evaluation Cycle-to-Cycle Variation

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80Cycle #

Max

P [

bar

]

14

14.1

14.2

14.3

14.4

14.5

14.6

14.7

14.8

14.9

15

IME

P [

bar

]

NoCO2_MaxP37%CO2_MaxPNoCO2_IMEP37%CO2_IMEP

9.7

9.8

9.9

10

10.1

10.2

10.3

10.4

10.5

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4vAf [m3CO2/m3(TNG+CO2)]

bsh

c [M

J/kW

h]

1340

1350

1360

1370

1380

1390

1400

bm

ep [

kPa]

bshcbmep

0

1000

2000

3000

4000

5000

6000

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4vAf [m3CO2/m3(TNG+CO2)]

CO

, H

C,

NO

[p

pm

]

0

2

4

6

8

10

12

14

16

18

CO

2, O

2 [%

]HCCONOCO2O2

50

52

54

56

58

60

62

64

66

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4vAf [m3CO2/m3(TNG+CO2)]

p_m

anif

old

[kP

ag]

600

620

640

660

680

700

720

740

t_ex

hau

st [

°C]

pK3pT1pK2tT1tT2



17

CVUT-JBRC OBEH – HR Recalculation StrategyOBEH – Recalculation of HR Pattern for Various Operational Conditions

spark

spark

spark

%90%90

%50%50

%5%5

G

H

F

ref

ref

ref

%90%90

%50%50

%5%5

i

i

ii

hH

gG

fF

fi,gi and hi are polynomial functions of:

Air excessPressure and temperature at 60° bTDCResidual gas (+EGR) fraction (?)Ignition timingEngine speed

0

500

1000

1500

2000

2500

3000

-100 -60 -20 20 60 100CrankAngle [°CA]

Tcy

l [K

]

0

10

20

30

40

50

60

70

pcy

l [b

ar]

Temperature

Pressure

1 1.6

0

0.2

0.4

0.6

0.8

1

1.2

-100 -60 -20 20 60 100CrankAngle [°CA]

Qn

m [

1]

0

0.01

0.02

0.03

0.04

0.05

dQ

nm

[1/

°CA

] 1 (reference)

Heat release

Rate-of-Heat-Release

Ignition

Qnm = const.

1.6 recalculated

Proven Usable for Various Fuel Compositions Providing: Reference cycle for Given Fuel is Available

Implemented into GT-Power Simulation



18

CVUT-JBRC GT-Power Model Layout

Three Pressure Analysis – TPA (Single Cylinder Model 4102/110)

Measured Intake Port Static Pressure

Measured In-cylinder Pressure Measured Exhaust

Port Static Pressure

Sampled TPA Outputs

pcyl, Tcyl, Tunb, Tburn, mcyl, Mass fractions



19

CVUT-JBRC GT-Power – TPA CalibrationThree Pressure Analysis – Results 1600 rpm, = 1, W.O.T.



20

0

1

2

3

-180 0 180 360 540 720

Crank Angle [dagCA]

pre

ssu

re [

ba

r]

pcyl_GTP Pcy pIN pEX

0

1

2

3

-180 0 180 360 540 720

Crank Angle [dagCA]

pres

sure

[bar

]

pcyl_GTP Pcy pIN pEX

bmep = 10.2 bar bmep = 2.1 bar

CVUT-JBRC GT-Power – TPA CalibrationThree Pressure Analysis – Results – 1600 rpm, = 1



21

CVUT-JBRC GT-Power - Layout

4102/120 Engine Model

0.5

1

1.5

2

2.5

3

-180 0 180 360 540 720

Crank Angle [deg CA]

pres

sure

[bar

], tu

rbin

e pr

essu

re

ratio

[-]

65000

66000

67000

68000

69000

turb

o sp

eed

[rpm

]

Pcyl_sim PCyl_measpiT_sim piT_meastb_speed_sim tb_speed_meas



22

CVUT-JBRC GT-Power – CalibrationEngine model Calibration Full Load Curves, VTG margins, Lean Burn

min rack pos.

max rack pos.



23

CVUT-JBRC GT-Power – CalibrationEngine model Calibration Full Load Curves, VTG margins, = 1

intake manifold

cylinder



24

CVUT-JBRC GT-Power Calibration

TPA Results 4102/120 Engine



25

CVUT-JBRC Knock Description

• Various types of knock models- chemical mechanism - empirical induction-time correlations

• Autoignition occurs when

Calls for:– Empirical relations for induction time for

methane (Constants A and B )

– Definition of end-gas temperature is crucial (Angle-Resolved Pattern of T )

it

t

dt0

11

T

BpA n exp



26


CHEMKIN3 Calculation (GRI-Mech3.0 Reaction Mechanism - 53 components/325 reaction)

0.01

0.1

1

10

100

1000

10000

100000

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.41000/T [1/K]

Ign

itio

n D

elay

[m

s]

p = 10 barp = 40 barp = 80bar

u

14

T18508

expp1013.8



27


End Gas Temperature Determination

Direct GT-Power Output

OBEH Output – Calculation Routine Based on 1st Law of Thermodynamics Uses Layer Thickness and its Heat Conductivity

Simplified Two-Zone Mean Temperature Model (Brunt, SAE Paper 981 052):

=1.338-610-5.T+1 10-8.T2

/11

SCSCu p

pTT



28

CVUT-JBRC Knock DescriptionRPM 1300, Full Throttle, no EGR, Light Knock,

Fuel = Transit Natural Gas

0

5

10

15

20

25

0 5 10 15 20 25Cycle # [-]

Kn

ock

On

set

[d

eg a

TD

C]

Knock Onset - Experiment

Knock Onset - Model before Calibration

Cycles Declared Knock-Free - Model before Calibration

Knock Onset - Calibrated Model

cvut-jbrc scope

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