phd dissertation proposal
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STUDY OF TRANSIT BUS DUTY CYCLE AND ITS INFLUENCE ON
FUEL ECONOMY AND EMISSIONS OF DIESEL ELECTRIC-HYBRIDS
Jairo A SandovalPh.D. Dissertation Proposal
Center for Alternative Fuels, Engines and EmissionsMechanical and Aerospace Engineering
West Virginia UniversityMarch 5th, 2010
Outline1. Motivation2. IBIS3. Objectives4. Methodology and Preliminary Results5. Contribution6. Timeline
2
1. MotivationEnvironmental effects of transportationVehicle duty cycle Fuel economy &
Emissions Hybrid buses will not perform the same on all
service routesEmissions and fuel economy correlate very
well with cycle metrics, but transit agencies do not know the metrics corresponding to their operation (e.g. acceleration or % idle)
3
Drive Cycle MetricsMetric Units
Percentage of Idle %
Stops per mile mi-1
Maximum Speed,
Acceleration (+/-),
Grade (+/-)
-
Average Speed mph
Average Speed w/o idle mph
Aerodynamic Speed mph
Standard Deviation of
Speedmph
Standard Deviation of
Speed w/o Idlemph
Metric Units
Average Acceleration ft/s2
Average Deceleration ft/s2
Characteristic
Accelerationft/s2
Kinetic Intensity mi-1
Average Time of a Stop s
Fractions in
Accel./Decel-Speed Bins%
Fractions in Grade Bins %
Mean Grade
Ascent/Descent%
4
100/%1
1
IdleVV idleno
2
~
aeroV
aki
Time, Distance, Energy, …
2. Integrated Bus Information System - IBISSome features are:
Searchable databases of transit vehicle emissions studies
Predictive emissions modeling toolsConstruction of virtual fleets
F.E., CO2, CO, NOx, HC, PM, NMHC
Diesel, CNG, Diesel-Electric Hybrid
Source: IBIS Presentation, July 20095
IBIS (Continued) Emissions data are
available on no more than 16 standard cycles + Idle cycle
Second-by-second data micro-trips new entries into the dataset
Chassis-dynamometer test data Correlations for fuel economy and
emissions Correction factors Current inputs:
(Average speed, Stops per Mile)
(Average speed, Percentage Idle)
(Average speed, Std. Dev. Speed)
(Average speed, Kinetic Intensity)
ΔSOC=0?
6
3. Objectives1. To characterize transit bus operation
Correlations between the information available to transit agencies and the cycle metricsEvaluation of in-use routes and their properties
2. To evaluate the effects of driving cycle on the F.E., CO2 and NOx emissions of diesel-electric hybrids
Variety of driving conditionsRegression based modelAllow transit agencies to assess the best routes for the hybrids
7
4. Methodology and Preliminary ResultsCharacterization of Transit Duty Cycles:
GPS logs of transit activityCollect information from transit agencyAnalysisDevelop correlations
Hybrid Bus Emissions ModelingMY 2007-2009 Allison Hybrid BusANN model for fuel, CO2, and NOx ratesDevelop hybrid controller / CalibrationSimulations / AnalysisDevelop correlations
8
4.1. Characterization of Transit Duty CyclesGPS logs of in-use
routes. 2,900 mi / 230 hr
Classify routes:×Stop-and-go×Urban×Suburban×Commuter×Express
9
Trip distance / Trip time in light and heavy traffic
Option: Process user-provided GPS logs and extract the metrics
4.1. Characterization of Transit Duty Cycles
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y= 55.1395 - 1.4102*x+ 0.0991 (x-13.2385)∙ 2
R2 = 0.6937
ŪNI=13.8
ŪNI=17.4
ŪNI=35.7
ŪNI=42.8
4.2. Vehicle Dynamic ModelThe Road Load Equation:
11
dt
dVVmmgVmgVccVbVVVAcP errfdroad sincos
2
1 22
Aerodynamic Loads due Rolling Elevation Inertial
Drag to Driveline Resistance Load Load
Friction
Vehicle Dynamic Model (Cont.)ANL’s PSAT:
12
Vehicle Dynamic Model (Cont.)ANL’s PSAT:
13
Vehicle Dynamic Model (Cont.)2-Mode Transmission:
14
Engine /Input
Ring 1
Sun 1
Motor A /Motor 2
Ring 2
Sun 2
Motor B /Motor 1
Ring 3
Sun 3
Output
C1
C2
E1 E2 E3
Ca
rrie
r 1
Ca
rrie
r 2
Ca
rrie
r 3
4 ω’s / 4 τ’s. 4 Eqns. 4 Degrees of Freedom (2 ω’s / 2 τ’s)+ ModeRemove output τ and ω
4.3. ANN Engine ModelEmissions tests of MY 2006 Allison Hybrids (17
cycles) and BAE Series Hybrids (6 cycles)Cummins ISL280, ISB 260H
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Speed (rpm)
Tor
que
(Nm
)
800 1000 1200 1400 1600 1800 2000 2200200
300
400
500
600
700
800
900
1000
1100
1200
0
0.2
0.4
0.6
0.8
1
1.2
1.4
In-use data – ISL 280 Chassis Tests – ISB 260H
ANN Engine Model (Cont.)Trust ECU torque and speedInputs: torque, speed, delayed first derivatives
(1, 5, 10 seconds)60% training, 20% validation, 20% testingCorrect for engine NOx certification levels
(2.5/1.5 g/brp-hr)
16
Input Output
radbasLayer
logsigLayer
tansigLayer
Output Layer(linear)
ANN Engine Model (Cont.)Generalization (Partial Training):
17
Unseen Cycles
Cycles Seen in Training
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1 2 3 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8
NO x
(g/
bh
p-h
r)
Measured Predicted
Arterial Braunschweig WMATA
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1 2 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 9
NO x
(g/
bh
p-h
r)
Measured Predicted
CBD New York Bus OCTA
Training Set
ANN Engine Model (Cont.)Performance (OCTA cycle):
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200 220 240 260 280 300 320 340 360 380 4000
5
10
Fuel R
ate
(g/s
)
Target
Output
200 220 240 260 280 300 320 340 360 380 400
5
10
15
20
25
CO
2 (g/s
)
200 220 240 260 280 300 320 340 360 380 4000
0.05
0.1
Time (s)
NO
x (g/s
)
ANN Engine Model (Cont.)Overall Performance
Fuel: 50% of results within 0.5% accuracy80% 1.1%95% 2.5%
CO2: 50% 1.3%80% 2.8%95% 5.8%
NOx: 50% 3%
80% 5%95% 10%
19
ANN Engine Model (Cont.)Performance of Fuel Model:
20
% E
rror
Fue
l
-4
-3
-2
-1
0
1
2
3
4
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
S.E
. Fue
l0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
% Error Standard Error, g/s
2
ˆ 2
2
n
yy
DFE
SSEMSESE ii
ANN Engine Model (Cont.)Performance of CO2 Model:
21
% Error Standard Error, g/s
% E
rror
CO
2
-6
-4
-2
0
2
4
6
8
10
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
S.E
. CO
20.0
0.5
1.0
1.5
2.0
2.5
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
ANN Engine Model (Cont.)Performance of NOx Model:
22
% Error Standard Error, g/s
% E
rror
NO
x
-15
-10
-5
0
5
10
15
20
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
S.E
. NO
x0.000
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.010
0.011
Art
eria
l
Bee
line
Bra
un
CB
D
Com
m
CS
HV
C
ET
CU
rban Idle
KC
M
Man
hatta
n
NY
Bus
NY
-Com
p
OC
TA
Par
is
Tra
ns
UD
DS
WM
AT
A
Cycle
5. ContributionCorrelate transit bus activity with
information available to transit agencies and cycle metricsIBIS Module
Effect of driving cycle on NOx, CO2, and F.C. Model to help transit agencies assess the best
routes for the hybridsIBIS Module
23
6. Timeline
24
ACTIVITY Done2010 2011
2 3 4 5 6 7 8 9 10 11 12 1 2 3
Collection of driving data
Sizing of hybrid bus components
Analysis of drive cycle data
Development and tuning of a controller for
the 2-mode hybrid bus
Development of engine fuel consumption,
CO2, and NOx model and inclusion in PSAT
Model validation
Computer simulations varying driving
conditions
Development of regression based emissions
model
Implementation in IBIS
Compilation of the document
Oral defense
Corrections and submission
Questions???
25
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