Impact of Advanced
Technologies on Medium-Duty
Trucks Fuel Efficiency
Antoine Delorme, Dominik Karbowski,
Aymeric Rousseau, Ram Vijayagopal
Argonne National Laboratory
SAE 2010 Commercial Vehicle
Engineering Congress
2010-01-1929
Presentation Outline
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Introduction
Vehicle Presentation and Description
Fuel Consumption Potential of Individual
Technologies
Fuel Consumption Potential of Combined
Technologies
Conclusion
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Introduction
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Several ways to improve vehicle fuel efficiency
Each component of the powertrain can be improved more or
less aggressively
Impact on vehicle fuel efficiency is different whether:
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Component improvements are considered separately
Advanced technologies are combined
Supported the National Academy of Science report
“Technologies and Approaches to Reducing the Fuel
Consumption of Heavy Duty Vehicles”
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Vehicle Characteristics
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Pickup Truck Class 2b
Based on a GMC Sierra 2500 HD
Component
Engine
Transmission
Model Characteristics
Diesel: Cummins 6.7 L, 272 kW
Gasoline: GM LM7 5.3 L, 276 kW
Automatic 6-speed
Tire
P245/75/R16 - Radius = 0.387 m - Rolling Resistance = 0.007
Vehicle Losses
Drag Coefficient = 0.44 - Frontal Area = 3.233 m2
Curb Weight
2659 kg
GVWR
4172 kg
Max. Payload
1513 kg
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Vehicle Model
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Vehicle model built in PSAT (Powertrain Systems Analysis Toolkit)
PSAT
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Forward-looking vehicle modeling and simulation software
Written in Matlab/Simulink/Stateflow
DOE’s primary vehicle modeling and simulation tool
Accelerator/Brake pedal
Motor
command
Engine
command
Controller Commands
Gear
command
Clutch
command
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Brake
command
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Potential of Individual Technologies
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Different advanced technologies considered separately
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Aerodynamics,
Rolling resistance,
Vehicle weight,…
Fuel consumption computed on the combined drive cycle
(UDDS+HWFET)
UDDS
HWFET
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Potential of Individual Technologies
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Improvements applied to two baseline architectures
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Conventional
Hybrid
Selected a pre-transmission parallel hybrid architecture
Engine
Final Drive
Transmission
Electric
Motor
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Wheels
Torque assist, engine ON/OFF, regenerative braking…
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Aerodynamic Improvements
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Aggressive reduction of drag coefficient: from 0.44 to 0.34
Significant technology development needed
Drag
Coefficient
0.44
Percent Fuel Saved
(Conventional)
0
Percent Fuel Saved
(Hybrid)
0
0.35
+2.7%
+3.4%
0.34
+3.0%
+3.8%
0.33
+3.3%
+4.2%
Savings consistent with light duty cars
Results may vary with different drive cycles
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Dieselization
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GMC Sierra 2500 HD available in both Gasoline and Diesel
Evaluate the Diesel fuel consumption advantage on different drive
cycles: UDDS, HWFET, LA92 and US06
All vehicles simulated at Gross Vehicle Weight
Improvements are only evaluated in comparison to the
conventional baseline
Drive Cycle
UDDS
Percent Fuel Saved
by the Diesel
(Volumetric)
18.3%
Percent Fuel Saved by
the Diesel (Gasoline
Equivalent)
9.1%
HWFET
25.3%
16.9%
LA92
20.4%
11.5%
US06
27.7%
19.5%
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Dieselization
Torque
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Traditional light duty vehicle diesel/gasoline fuel consumption
comparison is around 30% (volumetric)
Here, engine operated at low load
Torque
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Gasoline
Diesel
Speed
Speed
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Different numbers if a trailer is considered
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Tires
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A 10% rolling resistance coefficient reduction considered
From 0.007 to 0.0063
Consistent with the NAS report
Rolling
Resistance
0.007
Percent Fuel Saved
(Conventional)
0
Percent Fuel Saved
(Hybrid)
0
0.00665
+0.6%
+0.9%
0.0063
+1.2%
+1.6%
0.0059
+1.8%
+2.4%
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Engine Efficiency
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Baseline gasoline engine peak efficiency: 34.7%
Advanced engine technologies:
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Variable Valve Timing
Variable Valve Lift
Direct Injection
Could reach 38% peak efficiency
Engine Peak
Efficiency
34.7%
Percent Fuel Saved
(Conventional)
0
Percent Fuel Saved
(Hybrid)
0
38%
+8.6%
+8.9%
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Transmission
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Baseline vehicle already equipped with a 6-speed gearbox
Switch to 8-speed gearbox could lead to more fuel savings
If 4-speed was considered for baseline, significant fuel
savings
Transmission
Type
6-Speed
Automatic
8-Speed
Automatic
Percent Fuel
Saved if baseline
is 6-Speed
(Conventional)
0
Percent Fuel
Saved if baseline
is 4-Speed
(Conventional)
+4.6%
Percent Fuel
Saved if baseline
is 6-Speed
(Hybrid)
0
+1.7%
+6.2%
+1.4%
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Vehicle Weight
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No engine downsizing considered to optimize grade and
towing performances.
Curb weight reduced but same payload
Weight
Reduction (kg)
-100
Percent Fuel Saved
(Conventional)
+1.1%
Percent Fuel
Saved (Hybrid)
+1.0%
-136
+1.4%
+1.4%
-200
+2.1%
+2.0%
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Hybridization
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Architecture presented previously
Several power ratings can be chosen for the electric motor
Engine was not downsized
Electric
Machine Power
(kW)
50kW
Percent Fuel Saved
(Conventional)
+14.8%
100kW
+15.3%
50 kW is enough for cycles such as UDDS
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Individual Technologies Summary
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Fuel consumption savings summary for the selected advanced
technologies
Advanced
Technology
for…
Percent Fuel Saved
(Conventional)
Percent Fuel
Saved (Hybrid)
Aerodynamic
+3.0%
+3.8%
Tires
+1.2%
+1.6%
Engine
+8.6%
+8.9%
Transmission
+1.7%
+1.4%
Vehicle Weight
+1.4%
+1.4%
Hybridization
+14.8%
N/A
Different packages will now be simulated to compare their fuel
savings with the sum of individual gains.
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Combined Technologies
Combined
Technologies
Fuel Savings
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Fuel Consumption reduction is greater for the hybrid baseline
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<
Sum of Individual
Technologies
Fuel Savings
Components more efficient AND
Less charging required for the battery
Only the gasoline version is used for the simulation
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Combined Technologies
Aerodynam ics + W eight
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Combined Technologies
Aerodynam ics + W eight + Tires
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Combined Technologies
Aerodynam ics + W eight + Tires + Transm ission
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Combined Technologies
Aerodynam ics + W eight + Tires + Transm ission + Engine
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Combined Technologies
All Technologies
35.0%
Percent Fuel Saved
30.0%
25.0%
Hybrid CS
14.8%
Engine
20.0%
Transmission
RR
15.0%
10.0%
5.0%
0.0%
28.4%
Cd
8.6%
Weight
Hybrid improvements
1.7%
1.2%
3.0%
1.4%
Each
technology
Baseline improvements
Combination
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Conclusion
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Several component technologies have the potential to
significantly reduce fuel consumption for class 2b pickup
trucks.
Most assumptions could be achieved in the near future.
When all combined, almost 30% fuel consumption reduction
compared to the baseline.
Similar work could be done with:
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Different fuels: diesel, hydrogen, ethanol
Different cycles: Real-world drive cycles,…
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Acknowledgements/Contact
PSAT development was funded by Lee Slezak (US DOE)
This study was done to support the National Academ y of Science report
“Technologies and Approaches to Reducing the Fuel Consumption of Heavy
Duty Vehicles”
Other Papers at SAE COMVEC 2010:



Validation of a Line Haul Class 8 Combination Truck (2010-01-1998)
Hybridization of a Class 8 Line-Haul Truck (2010-01-1931)
Plug-and-Play Software Architecture to Support Automated Model-Based
Control Process (2010-01-1996)
adelorme@anl.gov / arousseau@anl.gov / www.autonomie.net
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