FLUID DYNAMICS TRANSIENT RESPONSE … · 1910 16v jtd engine alfa romeo 147 vehicle transient...
Transcript of FLUID DYNAMICS TRANSIENT RESPONSE … · 1910 16v jtd engine alfa romeo 147 vehicle transient...
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-SUITE USERS CONFERENCE
FRANKFURT, OCTOBER 20TH 2003
FLUID DYNAMICS TRANSIENT RESPONSE
SIMULATION OF A VEHICLE EQUIPPED WITH A
TURBOCHARGED DIESEL ENGINE USING GT-POWER
TEAM OF WORK:
A. GALLONE, C. VENEZIAFIAT RESEARCH CENTRE
ENGINE ENGINEERING DIVISION
FLUIDS AND COMBUSTION ANALYSIS DEPARTMENTFrankfurt, 20 - 10 - 2003
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
PRESENTATION OVERVIEW
� INTRODUCTION
� GT-POWER MODEL DESCRIPTION
� STEADY STATE ANALYSIS – FULL LOAD CURVE
� TRANSIENT ANALYSIS
� TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
2
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INTRODUCTION
THE IMPROVEMENT OF PASSENGER CARS EQUIPPED WITH TURBOCHARGED DIESEL
ENGINES HAS ASKED FOR A BETTER UNDERSTANDING AND OPTIMISATION OF THE FLUID
DYNAMICS PHENOMENA INVOLVED IN TURBO CHARGING.
AS WELL KNOWN, AN IMPORTANT EFFECT ON SUCH VEHICLE PERFORMANCE DURING
ACCELERATION PHASES IS DUE TO THE SO-CALLED “TURBOLAG”, THE ENGINE DELAY TO
A DRIVER’S REQUEST OF TORQUE.
USING THE 1D GT-POWER CODE VARIOUS TRANSIENT PHASES HAVE BEEN SIMULATED FOR
AN ALFA ROMEO 147 VEHICLE WITH 1.9 JTD ENGINE WITH A VGT TURBOCHARGER,
DURING ACCELERATIONS FROM 1000 ERPM TO 4500 ERPM WITH 2ND, 3RD, 4TH AND 5TH
GEARS.
THE CONTROL OF THE VARIABLE GEOMETRY TURBINE HAS BEEN IMPLEMENTED IN THE
MODEL USING GT-POWER CONTROL OBJECTS ONLY, IN ORDER TO KEEP THE SET-UP AS
EASY AS POSSIBLE. THE IMPLEMENTED CONTROL REPRODUCES THE REAL ECU STRATEGY.
3
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INTRODUCTION
THE SIMULATION RESULTS, IN TERMS OF ENGINE TORQUE, VEHICLE SPEED, ETC, HAVE
BEEN COMPARED WITH VEHICLE EXPERIMENTAL DATA, PROVIDED BY FGP ITALY, AND THE
AGREEMENT IS SATISFACTORY.
AS RESULT, THE ACTIVITY HAS SHOWN THE KEY ROLE PLAYED BY THE TURBOCHARGER
INERTIA.
AFTER THIS FIRST STEP OF VALIDATION OF THE MODEL AND THE CONTROL
METHODOLOGY, A SERIES OF PARAMETRIC ANALYSES HAS BEEN PERFORMED.
THE EFFECT OF TURBOCHARGER INERTIA MANUFACTURE SCATTERING, FINAL DRIVE GEAR,
VEHICLE WEIGHT AND VOLUME DOWNSTREAM OF THE COMPRESSOR ON THE VEHICLE-
ENGINE SYSTEM BEHAVIOUR HAS BEEN EVALUATED.
4
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
PRESENTATION OVERVIEW
INTRODUCTION
� GT-POWER MODEL DESCRIPTION
� STEADY STATE ANALYSIS – FULL LOAD CURVE
� TRANSIENT ANALYSIS
� TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
5
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GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
6
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
7
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
8
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
9
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
10
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
11
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
12
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
GT-POWER MODEL DESCRIPTION
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
13
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
PRESENTATION OVERVIEW
INTRODUCTION
GT-POWER MODEL DESCRIPTION
� STEADY STATE ANALYSIS – FULL LOAD CURVE
� TRANSIENT ANALYSIS
� TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
14
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STEADY STATE ANALYSIS – FULL LOAD CURVE
GT-POWER MODEL VALIDATION WITH EXPERIMENTAL DATA
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ENGINE M729 1910 16V JTD
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500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
EXPERIMENTAL
GT-POWER
ENGINE M729 1910 16V JTD
ENGINE M729 1910 16V JTD
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100
150
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500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
EXPERIMENTAL
GT-POWER
ENGINE M729 1910 16V JTD
Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
PRESENTATION OVERVIEW
INTRODUCTION
GT-POWER MODEL DESCRIPTION
STEADY STATE ANALYSIS – FULL LOAD CURVE
� TRANSIENT ANALYSIS
� TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
16
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TRANSIENT ANALYSIS
ADDITIONAL REQUIRED DATA FOR TRANSIENT ANALYSIS
1910 16V JTD ENGINE
ALFA ROMEO 147 VEHICLE
TRANSIENT SIMULATION PHASES1) THE FIRST PHASE IS NEEDED FOR IDENTIFYING THE INITIAL STEADY-STATE CONDITION
OF THE TRANSIENT. THIS MEANS THE CALCULATION OF THE FUEL REQUIRED FOR THE
BALANCE BETWEEN THE POWER SUPPLIED BY THE ENGINE AND WHAT REQUESTED BY THE
VEHICLE AT A GIVEN VEHICLE VELOCITY WITH FIXED GEAR.
2) THE SECOND PHASE IS THE PHYSICAL TRANSIENT: THE INPUT SIGNAL, CORRESPONDING
TO A FUEL STEP FROM PART LOAD TO FULL LOAD, IS APPLIED TO THE ENGINE AND THE
VEHICLE-ENGINE SYSTEM CHANGES DEPENDING ON ITS PHYSICAL LAWS.
- ENGINE INERTIA
- TURBOCHARGER INERTIA
- VEHICLE MASS
- FRONT AREA AND CX
- WHEELS INERTIA
- FINAL GEAR AND GEARS RATIOS
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TURBOCHARGER CONTROL FOR TRANSIENT ANALYSIS
INTAKE SYSTEM:
- AIR FILTER
- COMPRESSOR
- INTERCOOLER
- MANIFOLD
TURBOCHARGER
CONTROL
EXHAUST SYSTEM:
- MANIFOLD
- TURBINE
- EXHAUST NOZZLE
18
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TURBOCHARGER CONTROL FOR TRANSIENT ANALYSIS
1) A TURBINE RACK POSITION CONTROL IS NEEDED TO ADJUST THE BOOST PRESSURE
DURING THE TRANSIENT.
2) THE TURBINE RACK POSITION CONTROL STRATEGY DURING THE TRANSIENT IS THE
FOLLOWING: AT FIRST THE MOST CLOSED RACK POSITION IS EMPLOYED, AND THEN THE
FULL LOAD REGULATIONS ARE GRADUALLY USED NEAR THE TARGET BOOST PRESSURE
ACHIEVEMENT (THE PID CONTROL ADJUSTS ON STEADY-STATE MAP).
BOOST SENSOR
ENGINE RPM
SENSOR
RACK ACTUATOR
0.1 = MINIMUM TURBINE OPENING
1 = MAXIMUM TURBINE OPENING
PID
STEADY STATE RACK
SUM
LIMITER
19
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PRESENTATION OVERVIEW
INTRODUCTION
GT-POWER MODEL DESCRIPTION
STEADY STATE ANALYSIS – FULL LOAD CURVE
TRANSIENT ANALYSIS
� TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
20
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TRANSIENT ANALYSIS: RESULTS II GEAR
BOOST PRESSURE: THE COMPARISON BETWEEN THE STEADY-STATE AND TRANSIENT
BOOST PRESSURES SHOWS THE ENGINE DELAY TO A DRIVER’S REQUEST OF TORQUE, DUE
TO THE SO-CALLED “TURBOLAG”.
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
STEADY-STATE
II GEAR
TURBOLAG
STEADY-STATE BOOST PRESSURE
TRANSIENT BOOST PRESSURE
21
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TRANSIENT ANALYSIS: RESULTS II GEAR
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
-0.2-0.10.00.10.20.30.40.50.60.70.80.91.01.11.21.3
STEADY-STATE
II GEAR
PID RACK
STEADY-STATE RACK
ACTUATOR RACK
PID RACK
STEADY-STATE RACK
ACTUATOR RACK
TURBOLAG
ENGINE M729 1910 16V JTD – VEHICLE 147
CONTROL STRATEGY: THE PID CONTROL (PID RACK) ADJUSTS TO GET THE TARGET BOOST
PRESSURE (STEADY-STATE BOOST PRESSURE) WORKING ON STEADY-STATE MAP
(STEADY-STATE RACK). THE RESULTANT SIGNAL (ACTUATOR RACK) OPERATES ON THE
TURBINE RACK POSITION. THE GRADUAL ADJUSTEMENT OF THE ACTUATOR RACK AVOIDS
THE OVERBOOST PRESSURE AND ITS OSCILLATIONS.
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TRANSIENT ANALYSIS: RESULTS II GEAR
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ENGINE M729 1910 16V JTD - VEHICLE 147
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500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
STEADY-STATE
II GEAR
ENGINE M729 1910 16V JTD – VEHICLE 147
THE EXPERIMENTAL VEHICLE TORQUE IS DERIVED FROM ACCELERATION MEASUREMENTS,
SOLVING THE MOTION EQUATION.
EXPERIMENTAL RESULTS
GT-POWER RESULTS
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TRANSIENT ANALYSIS: RESULTS II GEAR
ENGINE M729 1910 16V JTD - VEHICLE 147
0
50000
100000
150000
200000
250000
300000
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
0.00.20.40.60.81.01.21.41.61.82.02.22.42.62.83.0
STEADY-STATE
II GEAR
TURBOCHARGER SPEED
TURBINE EXPANSION RATIO
THE TURBOLAG PHENOMENON IS MAINLY RELATED TO THE TURBOCHARGER INERTIA.
THE GRADUAL ADJUSTEMENT OF THE ACTUATOR RACK AVOIDS THE INCREASE OF
TURBINE EXPANSION RATIO ABOVE THE STEADY-STATE VALUES, LIMITING THE
OVERBOOST AND THE TURBOCHARGER OVERSPEED EFFECTS.
24
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TRANSIENT ANALYSIS: RESULTS II GEAR
TYPICAL VEHICLE RESULTS ARE THE VEHICLE SPEED, VEHICLE ACCELERATION AND
VEHICLE JERK (ACCELERATION DERIVATIVE).
ENGINE M729 1910 16V JTD - VEHICLE 147
0
7
14
21
28
35
42
49
56
63
70
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
TIME [s]
-1.0
-0.4
0.2
0.8
1.4
2.0
2.6
3.2
3.8
4.4
5.0
II GEAR
VEHICLE ACCELERATION
VEHICLE JERK
VEHICLE SPEED
25
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TRANSIENT ANALYSIS: RESULTS III GEAR
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
-0.2-0.10.00.10.20.30.40.50.60.70.80.91.01.11.21.3
STEADY-STATE
III GEAR
PID RACK
STEADY-STATE RACK
ACTUATOR RACK
STEADY-STATE BOOST PRESSURE
TRANSIENT BOOST PRESSURE
26
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TRANSIENT ANALYSIS: RESULTS III GEAR
GT-POWER RESULTS
ENGINE M729 1910 16V JTD - VEHICLE 147
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500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
STEADY-STATE
III GEAR
ENGINE M729 1910 16V JTD – VEHICLE 147
EXPERIMENTAL RESULTS
27
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TRANSIENT ANALYSIS: RESULTS IV GEAR
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
-0.2-0.10.00.10.20.30.40.50.60.70.80.91.01.11.21.3
STEADY-STATE
IV GEAR
PID RACK
STEADY-STATE RACK
ACTUATOR RACK
STEADY-STATE BOOST PRESSURE
TRANSIENT BOOST PRESSURE
28
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TRANSIENT ANALYSIS: RESULTS IV GEAR
29
THE CALCULATED TRANSIENT BOOST PRESSURE SHOWS A DELAY COMPARED TO
THE STEADY-STATE ONE.THE CALCULATED TRANSIENT TORQUE
REACHES THE STEADY-STATE VALUES IN ADVANCE FOR THE EMPLOYED COMBUSTION
MODEL (FULL LOAD COMBUSTIONS).
GT-POWER RESULTS
ENGINE M729 1910 16V JTD - VEHICLE 147
50
100
150
200
250
300
350
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
0
1000
2000
3000
4000
5000
6000
STEADY-STATE
IV GEAR
TRANSIENT BOOST PRESSURE
ENGINE TORQUE
ENGINE M729 1910 16V JTD – VEHICLE 147
EXPERIMENTAL RESULTS
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TRANSIENT ANALYSIS: RESULTS V GEAR
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
-0.2-0.10.00.10.20.30.40.50.60.70.80.91.01.11.21.3
STEADY-STATE
V GEAR
PID RACK
STEADY-STATE RACK
ACTUATOR RACK
STEADY-STATE BOOST PRESSURE
TRANSIENT BOOST PRESSURE
30
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TRANSIENT ANALYSIS: RESULTS V GEAR
31
THE CALCULATED TRANSIENT BOOST PRESSURE HAS NOT A DELAY COMPARED TO
THE STEADY-STATE ONE.THE CALCULATED TRANSIENT TORQUE
EXCEEDS THE STEADY-STATE VALUES FOR THE EMPLOYED COMBUSTION MODEL (FULL LOAD
COMBUSTIONS).
GT-POWER RESULTS
ENGINE M729 1910 16V JTD - VEHICLE 147
50
100
150
200
250
300
350
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
0
1000
2000
3000
4000
5000
6000
STEADY-STATE
V GEAR
TRANSIENT BOOST PRESSURE
ENGINE TORQUE
ENGINE M729 1910 16V JTD – VEHICLE 147
EXPERIMENTAL RESULTS
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TRANSIENT ANALYSIS: RESULTS II, III, IV AND V GEARS
IN TERMS OF BOOST PRESSURE THE FLUID DYNAMICS EFFECT OF TURBOLAG IS
CORRECTLY CALCULATED BY THE CODE.
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
STEADY-STATEII GEARIII GEARIV GEARV GEAR
32
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TRANSIENT ANALYSIS: RESULTS II, III, IV AND V GEARS
BASED ON ENGINE SPEED THE TURBOLAG
SEEMS TO BE GREATER FOR LOWER GEARS.
ACTUALLY THE TURBOLAG IN TERMS OF
TIME IS LONGER FOR THE HIGHER GEARS
BECAUSE THE ENGINE SPEED INCREASES
MORE SLOWLY.
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10 15 20 25 30 35 40 45 50 55
TIME [s]
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
ENGINE M729 1910 16V JTD – VEHICLE 147
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
0 5 10 15 20 25 30 35 40 45 50 55
TIME [s]
II GEAR
III GEAR
IV GEAR
V GEAR
33
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PRESENTATION OVERVIEW
INTRODUCTION
GT-POWER MODEL DESCRIPTION
STEADY STATE ANALYSIS – FULL LOAD CURVE
TRANSIENT ANALYSIS
TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
� TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
34
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TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
THE EFFECT OF THE FOLLOWING PARAMETERS ON THE MODEL HAS BEEN EVALUATED:
• TURBOCHARGER INERTIA WITH 2ND GEAR, ANALYSING A POSSIBLE MANUFACTURE
SCATTERING OF ± 5% AND ± 10% FOR THE SAME TURBOCHARGER.
• HIGH PRESSURE INTAKE SYSTEM VOLUME WITH 2ND GEAR, REDUCING THE LENGTH
OF THE PIPES BETWEEN COMPRESSOR AND INTERCOLER AND BETWEEN INTERCOOLER
AND INTAKE MANIFOLD (REDUCTION FROM 6.3 TO 4.3 LITRES OF HIGH PRESSURE
VOLUME).
• VEHICLE WEIGHT WITH 2ND, 3RD, 4TH AND 5TH GEARS, INCREASING ITS VALUE OF 200 KG.
• FINAL GEAR RATIO WITH 2ND, 3RD, 4TH AND 5TH GEARS, INCREASING ITS VALUE OF 10%.
35
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TRANSIENT ANALYSIS: TURBOCHARGER INERTIA EFFECT
36
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
ENGINE M729 1910 16V JTD – VEHICLE 147
ENGINE M729 1910 16V JTD - VEHICLE 147
0
7
14
21
28
35
42
49
56
63
70
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0
TIME [s]
-1.0
0.2
1.4
2.6
3.8
5.0
6.2
7.4
8.6
9.8
11.0II GEAR - TURBOCHARGER INERTIA BASELINEII GEAR - TURBOCHARGER INERTIA -5%II GEAR - TURBOCHARGER INERTIA +5%II GEAR - TURBOCHARGER INERTIA -10%II GEAR - TURBOCHARGER INERTIA +10%
VEHICLE SPEED VEHICLE ACCELERATION
VEHICLE JERK
THE TURBOCHARGER INERTIA EFFECT, DUE TO THE
MANUFACTURE SCATTERING, IS LIMITED IN TERMS OF
BOOST PRESSURE OR VEHICLE PERFORMANCE.
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TRANSIENT ANALYSIS: HIGH PRESSURE VOLUME EFFECT
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ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
ENGINE M729 1910 16V JTD – VEHICLE 147
ENGINE M729 1910 16V JTD - VEHICLE 147
50
100
150
200
250
300
350
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
RPM
STEADY-STATE - VOLUME 6.3 l
STEADY-STATE - VOLUME 4.3 l
II GEAR - VOLUME 6.3 l
II GEAR - VOLUME 4.3 l
DURING TRANSIENT THE EFFECT OF HIGH
PRESSURE VOLUME REDUCTION (32%) IS
LIMITED IN TERMS OF BOOST PRESSURE.
IN STEADY-STATE CONDITION THE PIPES LENGTH
REDUCTION CHANGES THE BEHAVIOUR OF THE
VOLUMETRIC EFFICIENCY AND THEN THE ENGINE TORQUE.
THE TRANSIENT ENGINE TORQUE IS AFFECTED BY THE
STEADY-STATE CURVE.
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TRANSIENT ANALYSIS: VEHICLE WEIGHT EFFECT
DURING TRANSIENT THE VEHICLE WEIGHT INCREASES THE ENGINE DELAY TO A DRIVER’S REQUEST OF TORQUE.
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0
TIME [s]
II GEAR BASELINEIII GEAR BASELINEIV GEAR BASELINEV GEAR BASELINEII GEAR - WEIGHT + 200 KGIII GEAR - WEIGHT + 200 KGIV GEAR - WEIGHT + 200 KGV GEAR - WEIGHT + 200 KG
38
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TRANSIENT ANALYSIS: FINAL GEAR RATIO EFFECT
DURING TRANSIENT THE VEHICLE FINAL GEAR RATIO INCREASES THE ENGINE DELAY TO A DRIVER’S REQUEST OF TORQUE.
ENGINE M729 1910 16V JTD - VEHICLE 147
1000
1500
2000
2500
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0
TIME [s]
II GEAR BASELINEIII GEAR BASELINEIV GEAR BASELINEV GEAR BASELINEII GEAR - FINAL GEAR RATIO +10%III GEAR - FINAL GEAR RATIO +10%IV GEAR - FINAL GEAR RATIO +10%V GEAR - FINAL GEAR RATIO +10%
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PRESENTATION OVERVIEW
INTRODUCTION
GT-POWER MODEL DESCRIPTION
STEADY STATE ANALYSIS – FULL LOAD CURVE
TRANSIENT ANALYSIS
TRANSIENT ANALYSIS: RESULTS WITH 2ND, 3RD, 4TH AND 5TH GEARS
TRANSIENT ANALYSIS: PARAMETRIC EVALUATIONS
� REMARKS AND CONCLUSIONS
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TRANSIENT SIMULATION REMARKS
THE TRANSIENT SIMULATION REQUIRES A VERY GOOD AND DETAILED STEADY-STATE
MODEL.
THE SETTING OF THE CONTROL PARAMETERS (PID) HAS BEEN CARRIED OUT IN 2ND GEAR,
WHERE THE CONTROL HAS TO BE FASTER FOR THE HIGHER ENGINE-VEHICLE
ACCELERATION; THE DETECTED PARAMETERS DON’T CHANGE FOR THE SIMULATIONS
WITH THE OTHER GEARS.
THE PARAMETRIC ANALYSIS FOR DIFFERENT GEARS IS VERY SIMPLE: IT IS ENOUGH TO
CHANGE THE GEAR NUMBER.
THE GT-POWER CALCULATION TIME ON PC (INTEL PENTIUM 4 - CPU 1500 MHZ) VARIES FROM
30 MINUTES (II GEAR) TO 90 MINUTES ABOUT (V GEAR) FOR THE ANALYZED
CONFIGURATION.
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CONCLUSIONS
BY THE USE OF ONE DIMENSIONAL GT-POWER CODE IT IS POSSIBLE:
• TO ANALYZE ENGINE-VEHICLE TRANSIENTS, ALSO CONSIDERING THE RESPONSE
DELAY FOR TURBOCHARGED ENGINES, DUE TO THE TURBOLAG EFFECT.
• TO STUDY THE PERFORMANCE SUPPLIED BY THE ENGINE-VEHICLE SYSTEM FOR
DIFFERENT ENGINE OR VEHICLE PARAMETERS.
BY THIS CALCULATION METHODOLOGY IT IS POSSIBLE TO DEFINE THE BEST FLUID
DYNAMICS LAYOUT FOR THE INTAKE AND EXHAUST MANIFOLDS AND TURBOCHARGER
TYPE FOR TURBOCHARGED ENGINES, EVALUATING THE STEADY-STATE AND TRANSIENT
PERFORMANCE.
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Frankfurt, 20 - 10 - 2003 Centro Ricerche Fiat is the sole owner of this document. It cannot be copied or given to third parties without permission.
ACKNOWLEDGEMENTS
THE AUTHORS WISH TO THANK GAMMA TECHNOLOGIES INC., FOR THE SUPPORT PROVIDED
CONCERNING THE GT-POWER CODE AND, IN PARTICULAR, TO JOHN WILKEN FOR HIS
HELPFUL SUGGESTIONS.
FINALLY A SPECIAL THANK IS DUE TO LUIGI PILO (FGP - ITALY) FOR PROVIDING THE
VEHICLE EXPERIMENTAL DATA AND TO MARCO TONETTI (CRF) FOR HIS SUGGESTIONS
ABOUT THE REAL CONTROL SYSTEM STRATEGY.
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