11% to 12% increase in fuel economy for flat backed trucks
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Transcript of 11% to 12% increase in fuel economy for flat backed trucks
Application of Pneumatic Aerodynamic Technology to Improve Drag Reduction, Performance, Safety, and Control of
Advanced Automotive Vehicles by Robert J. Englar, Georgia Tech Research Institute
Application of Pneumatic Aerodynamic Technology to Improve Drag Reduction, Performance, Safety, and Control of
Advanced Automotive Vehicles by Robert J. Englar, Georgia Tech Research Institute
Application of Advanced Pneumatic Aircraft Technology….
...Through Analytical &Experimental Development ...
..To Proof-of-ConceptFull-Scale Tests
Outline of Presentation
• Introduction: Pneumatic Heavy Vehicle Aerodynamic Technology• Pneumatic Heavy Vehicles (PHV)….Multi-Purpose Aero Devices for: Force & Moment Reductions or Augmentations Drag Reduction (Fuel Efficiency) or Drag Increase (Aero Braking) Increased Stability (Directional & Lateral) Improved Safety of Operation Reduced Spray Turbulence & Hydroplaning No-Moving-Part Integrated System Pneumatic Cooling System • Wind-tunnel Investigations &Confirmations• Initial Full-Scale Tuning Tests at Volvo Trucks • SAE Type II Fuel Economy Tests at TRC• Other Applications: Pneumatic SUV & Aero Heat Exchanger• Conclusions: Summary of Wind-Tunnel & Full-Scale Results
Basics of Circulation Control Pneumatic Aerodynamics and Application to Heavy Vehicles
Circulation Control Concept on Aircraft Navy A-6/CCW Flight Test Aircraft
Blowing on Front of Trailer and/or All 4 Trailing Edges
Pneumatic Aero Development at GTRI Showed 50%(or more) Drag Reduction, Force & Moment Augmentation from Blown Configurations, and
Drag Increase for Aero Braking if Desired
4 Blown Slots & Jet Turning on Rear Doors of Wind-Tunnel Model
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
CD
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20Momentum Coefficient, C
0.065-Scale GTRI Blown Heavy Vehicle Drag &Aero Modifications; 0.375"R Circular Arc 90°TE , Wheels on, q=11.86 psf, V=70 mph, =0°, =0°
CD=0.627
CD=0.824
Top & Bottom Slots Only=Drag Increase for Braking
All Four 90° Slots Blown= Drag Reduction
Unblown Baseline,No Gap,Square LE+TE
Unblown Baseline, Unfaired,Full Gap
Side Slots Only=Yaw orAnti-Yaw
Blown Truck,Low Cab, No Gap,Round Top LE, 0.375"R, 90° TE
90°/30° 1/2"plte TE, All 4 Slots Blown
0.25 psig
0.5 psig0.75 psig
1.0 psig
CD Due toGAP
CD Due to RoundedUnblown LE&TE
-23.9%
-10.2%
CD due to Blowing-26.8%
GTRI Extended C Tests Showed State-of-the-Art Drag Reduction!!
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
CD
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1Momentum Coefficient, C
h=0.01", 0.375"R Circular Arc 90°/30°1/2"TE, LE & TE Blowing, Wheels on,
Cab/Trailer Gap Plates E Installed, =0°, =0°
q=6.1 psf, V=51 mph
q=11.9, V=70.9 mph,
q=25 psf,V=103.0 mph
Unfaired UnblownBaseline HV, C D=0.824
BlownHeavyVehicle
CD=0.29
CD=0.33
CD=0.25
1999 Ferrari 550
1999 Corvette Coupe
2001 Honda Insight
Directional Control Capability Provided by Blowing of
Left Side Slot Only (Similar Effects on Drag)
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
CN =Half Chord Yawing Moment Coefficient
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20Momentum Coefficient, C
90°/30° 1/2"plate TE , 0.375"R=0°, Wheels ON, Left Slot Blowing Only
Nose Right
Nose Left
=-8°, Nose Yawed Left
=0°, Nose Straight Ahead
Yawing MomentTrimmed by Blowing
Blowing Produces ExcessYaw in Opposite Direction
CN
UNSTABLE
Additional Gain from Side Blowing =Reduced CD due to Yaw
Yaw Nose Left, Blow HERE
Static Jet Turning Displayed During Full-scale Run-up Testing
Setting Slot Heights and Confirming Jet Turning at Low Blowing Rate on Aft Door of Trailer
Right Rear Corner, looking up--Tufts Show Jet Turning to Left:
90° on Side and 30° on Top
Slots, 4 total, one per side
Tufts
On-the-Road Operation: Jet Turning Entraining the Freestream Flowfield and Reducing Vehicle Drag
Rear View with Jets Blowing
Close-up of Tufts Showing Jet Turning
Pneumatic Heavy Vehicle (PHV) Test Rig on Track for Fuel Test 1 at TRC, 75 mph with Blowing
SAE Fuel Test I Results: 5-6% Fuel Economy Increase ~ 10-12% CD Reduction New Wind Tunnel Tests wereConducted to Identify Initial Problem areas, then Fuel Test II was conducted in Sept. 2004
Updated PHV Blown Wind-tunnel Model to Resemble TRC Test Rig,
With New Tractor, New Top Strut Mount, New TE Geometry
Airfoil Airfoil
New Blown Trailing-edge Geometry,
53’ Trailer
High Floor, Wheels & Undercarriage Details, No Fairing
Generic Conventional Model (GCM) Cab(DOE Team design)
Faired Mounting Strut
Air Supply Line
Optional Gap Side Plates
Tests of this new model completed at GTRI; Showed 31% Lower CD than Stock Truck
Second SAE Type II Fuel Economy Test at TRC
Revised Pneumatic Heavy Vehicle Test Rig
Baseline Stock Heavy Vehicle Control Truck
SAE Fuel Economy Results at TRC, Test 2 - Improvements due to Blowing and Aft Trailer Geometry
0
2
4
6
8
10
12
14
%FEI=% Chng in MPGfrom Base-line HV
0 0.01 0.02 0.03 0.04 0.05
Momentum Coefficient C
TRC On-Track (9/04) SAE Type -II Fuel Economy Test Results
(Blower fuel not included.except as noted)
PHV Total, V=65mph
PHV Total, V=75mph
PHV, Blowing Only,V=65mph
PHV, Blowing Only,V=75mph
T/C = 1.00 forBaseline ReferenceTruck
PHV Total FuelIncluded, PulsedBlowing, V=75mph
PHV Total, FuelIncluded, PB,V=65mph
Estimated%FEI fromWind-tunnelData
Fuel Usage in the US (look at SUVs), and One Possible Fix:Increase Fuel Efficiency of SUVs
DOE Fuel Usage Data, 109 gallons/year Blown SUV in Lockheed Tunnel
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
110.0
120.0
130.0
140.0
150.0
160.0
BGY
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020Year
(Source: Refs. 12 and 13)
Total Fuel Consumed
Domestic Oil Production
Autos
Light Trucks, SUVs(Class 1&2a)
Heavy Trucks (Class 2b-8) & Buses (No Military Vehicles)Report Date
"Gap"
BGY=Billions of Gallons per Year
Full-Scale Tunnel Tests of Unblown SUV to Locate Flow Separation for Blowing Slot Location of Pneumatic SUV
Smoke Flow over Unblown SUV ,Testing in Lockheed 16’ x 23’ Low Speed Wind Tunnel, Marietta GA
Separated Flow over Aft Door of SUV
Pneumatic Capabilities of Blown SUV Confirmed in WT Test;Blowing Configs far from Optimized
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
Cyaw
0 0.01 0.02 0.03 0.04 0.05 0.06
Left Slot Momentum Coefficient, C
LSWT Test 1853, Run 17, Left Side Slot ONLY, V=50 mph, All Jet Turning Corners are 45°
NoseRight Cyaw required to offset =-15° unblown
Cyaw required to offset =-10° unblown
Cyaw required to offset =-5° unblown
0.44
0.46
0.48
0.50
0.52
0.54
0.56
CD
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
Momentum Coefficient, C
PSUV Drag Variation with Blowing, V=50mph(Blowing Geometry not yet Optimized)
Run 12, 45° Top, Bottom & Bottom Sides; 90° Top Sides
Run 11, 45° Top & Bottom; 90° Sides
Run 14, 45° All Sides
Drag Reduction or Aero Braking~Functions Interchangeable: Which Slot Blown
Directional Stability,No Moving Parts
CONCLUSIONS: Pneumatic Aerodynamic Concepts Now Demonstrated Full-Scale on PHV and PSUV
Blowing Demonstrated on Full-Scale PHV Tests at TRC, Confirming Drag Reduction, but less than from Tunnel Tests; Reasons Now Identified
15-16% Fuel Efficiency Improvement is PossibleBased onModelCD Reduction ~TRC Track Test Results Show 11-12% Fuel Economy Increase due to Blowing and Aft Geometry (not including blower fuel; better blower or pump would help) Pneumatic Yaw Stability, Side-Wind CD Reduction, and Aero Braking Capabilities
(Safety of Operation) are Confirmed, Model & Full-scale Testing
Pneumatic Full-scale Tunnel Tests Showed Similar Blown Capabilities for SUVs
• Let’s get this on Production Trucks & Fleets!! (12%FEI=2.4 Billion gals of diesel/yr)
GTRI PATENTED CONCEPTS
BACKUP Slides
The Effects of Blowing on Increasing Base Pressure for CD Reduction
TheVertical Mid Base
Vertical Mid Base
Horizontal Mid Base
Flow Visualization of Blowing Jets
Tuft Showing Flow Uniformity at Diffuser Center
Combined Jet Strength and Wake Contraction (see Shirt)
Blowing Efficiency & Drag/Thrust Increment Due to Blowing Slot Position, shown as Fraction/Multiple of Blowing Momentum Input
-5.5
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
CD/C
-0.15-0.12-0.09-0.06-0.03-0.000.030.060.090.120.15
CD = CD-CD0
Low Cab, No Gap, Round LE,0.375"R Circular Arc 90°TE, q=11.86psf, V=70mph , =0°, Re=2.5 x 10**6
Note: CD0 = CD at C=0
All 4 SlotsBlown
Bottom Slot OnlyTop & BottomSlots
Top Slot Only
2 Side Slots Only
90/30°,1/2"plate TE, All 4 Slots Blown
CD/CMomentum Recovery
Figure 6 - Blowing Efficiency & Drag Increments due to Blowing Slot Location
It’s possible to get back 5.5 times the C input as a CD Reduction….
OR 2 times the C input as Aero Braking increase