28 April 2006 Team 4/5 Slide 1
Prototype Review 2Prototype Review 2
Dan Tyburski
Bryan Marlow
Philip Poll
Jason Gray
Matt Decker
Julio Cumba
Chris Short
Katie Melton
Mike Caples
Eric Krouse
TJ Cyders
Craig Foglesong
Adam Koloff
Adam Shank
Chris Williams
Jared Donnamiller
28 April 2006 Team 4/5 Slide 2
Presentation OverviewPresentation Overview
EPCT Powertrain Components SelectedMotor, batteries, controller
Predictions of Prototype PerformanceUpdated Matlab simulation results
Fuel EconomyPredicted Measuring during competition
Determination of “Best” VehiclePrototype Status and Plans for Qualification
28 April 2006 Team 4/5 Slide 3
H3R Powertrain H3R Powertrain Component OverviewComponent Overview
Briggs and Stratton Etek motor4 VRLA Panasonic batteriesNavitas TPM400 controllerChain drive, 6.25:1 gear ratio
28 April 2006 Team 4/5 Slide 4
Targeted Performance SpecsTargeted Performance SpecsFully Loaded Vehicle: 600 lbs
Speed: 19.5 mph , fully loaded
Acceleration: min of 1.5 m/s2 up to 10 mph; min of 0.5 m/s2 up to 18 mph
Gradeability: Ascend max grade of 10% for 1/8 mile; maintain 15 mph up 5% grade
Range: At least 20 miles in 14 hour period
28 April 2006 Team 4/5 Slide 5
Matlab Simulation:Matlab Simulation:Speed, Acceleration, GradeabilitySpeed, Acceleration, Gradeability
Mass: 600 lb = 272 kgWheel mass: 9 lb = 4 kg eachWheel radius: 6.25 in = .159 mGear ratio: 6.25 : 1Frontal Area: 11.8 ft2 = 1.1 m2
Battery Voltage: 48 VoltsCurrent Limit: 90 ampsMotor resistance: 0.145 OhmTorque constant: 1.14 in-lb/A = 0.13 Nm/ACoeff. Of Drag: 0.5Coeff. Of Rolling: 0.01Air Density: 0.07 lb/ft3 = 1.2 kg/m3
28 April 2006 Team 4/5 Slide 6
Speed and Acceleration Speed and Acceleration ACCELERATION
• 90 amps current limiting
• After 3 sec, 10 mph
• Acceleration of 1.5 m/s2
attained (up to 18 mph)
Acceleration Spec: min of 1.5 m/s2 up to 10 mph; min of 0.5 m/s2 up to 18 mph
SPEED
• Max. speed = 21.2 mph
Speed Spec: 19.5 mph
Peak power = 3100 W
(1/20th scale)
28 April 2006 Team 4/5 Slide 7
Gradeability Gradeability –– 10% Grade10% Grade• Maximum speed of 17.7 mph
• Max acceleration of 0.5 m/s2
Gradeability: Ascend max grade of 10% for 1/8 mile
28 April 2006 Team 4/5 Slide 8
Gradeability Gradeability –– 5% Grade5% Grade• Maximum speed of 19.5 mph
• Max acceleration of 1.0 m/s2
Gradeability: maintain 15 mph up 5% grade
28 April 2006 Team 4/5 Slide 9
RangeRange• Battery discharge curve calculation would only yield a rough estimation of range
• Physical test more appropriate
• Plan on running simulated drive cycle (competition course) and recording distance traveled until vehicle no longer maintains full performance capabilities
28 April 2006 Team 4/5 Slide 10
Approximating Energy UseApproximating Energy Use5 Trips, 2 miles Each:
• 3 Accelerations• 0-10 mph
@ 1.5 m/s2
• 6 Accelerations• 10-19.5 mph
@ 0.5 m/s2
• ½ mile• 5% grade
@ 15 mph
• 1/8 mile• 10% grade
@ 10 mph
• 1 ¼ mile• 0% grade (steady-state)
@ 19.5 mph
*w/o 10 additional miles @ steady state826 Wh
160480120010
180288022560
280168060035
152182430038
5443204590
Energy (Wh)
Power (W)
Time (s)
Current (A)
28 April 2006 Team 4/5 Slide 11
Energy UseEnergy Use
kWhmiles
kWhmiles 11.12
826.10
=
• Energy content of gasoline = 33.5
• Equivalent Fuel Economy = =∗galkWh
kWhmiles 5.3311.12 405.7 mpgge*
• Assuming 80% Overall Powertrain Efficiency:
Fuel Economy = 325 mpgge
Expected Fuel Economy = 275 – 350 mpgge
* mpgge = miles per gallon, gasoline equivalent
galkWh
28 April 2006 Team 4/5 Slide 12
Measuring Energy Use Measuring Energy Use During CompetitionDuring Competition
Known: System voltage = 48 V System amp hour capacitance = 33 A hr
1. Measure system voltage after race2. Using approximate running time, find average current draw
from battery discharge curve3. Subtract current draw from amp hour capacitance4. Multiply remaining amp hours with remaining voltage5. Subtract kWh (after race) from kWh (before race) to find
kWh used 6. Knowing distance driven, calculate miles per kWh and mpgge
28 April 2006 Team 4/5 Slide 13
Energy Use ExampleEnergy Use Example
===kWhmiles
kWhmiles 75.7
29.110
System:
Before = 48 V* 33 Ah =1.58 kWh
After = 40.8 V, X Ah = Y kWh
• 10.2 V per battery left after 2 hour running time
• Avg. current draw = 13 A
• 13 A * 2 hr = 26 Ah used
• 33 Ah – 26 Ah = 7 Ah remain
• 40.8 V * 7 Ah = .287 kWh remain
•1.58 kWh - .287 kWh = 1.29 kWh
260 mpgge
28 April 2006 Team 4/5 Slide 14
Determination of “Best” VehicleDetermination of “Best” Vehicle
3 Vehicles awarded 1st, 2nd, or 3rd in:
Vehicle Efficiency (mpg, mpgge) – 55%Competition Course Placement – 25%Vehicle Aesthetics – 20%
“Best” vehicle awarded to team with lowest score
28 April 2006 Team 4/5 Slide 15
Prototype Status andPrototype Status andQualification PlansQualification Plans
Qualification To-Do List:Finish installation and test braking systemMount adjustable steering mechanism and seatbeltAdd battery charge gauge to prevent inoperable vehicleImplement battery plug for recharging demonstration
Non-Qualification To-Do List:Front bumper, dash/steering gauges, entrance/exit handle, cargo lid, paint frame
Safety Qualification & Specification CheckMonday, May 2 @ 5pm
28 April 2006 Team 4/5 Slide 16
Questions?Questions?
28 April 2006 Team 4/5 Slide 17
Voltage Constant 72 RPM per Volt
Torque Constant 1.14 in-lb per Amp
Stall Current 330 A (for 1 minute)
Rated Peak Output 15 Hp
Rated Continuous Output 6 Hp
Maximum Torque 32 ft-lb
Maximum No-Load Current 6 A
Maximum Motor Voltage 48 V
Vender for Prototype Robotmarketplace.com Price: $450.00
Vender in Lots of 5000 Briggs & Stratton (direct)
Estimated Price: $405.00(Retail less 10%)
.
Estimated Price: $400-500If controller is made specifically for
our vehicle application in lots of 5000.
Navitas Technologies Ltd.Vender in Lots of 5000
Price: $595CloudElectric.comVender for Prototype
0-5kΩ, 5kΩ-0, or bi-directionalAnalog Throttle Input
16 VBattery Under-Voltage Limit
62 VBattery Over-Voltage Limit
400 ACoast Regen Current (Max)
400 ABraking Regen Current (Max)
330 A (for 1 minute)Stall Current
200 AMaximum Continuous Current
400 AMaximum Peak Current
28 April 2006 Team 4/5 Slide 18
Power 2.8 hpTorque (at the wheel) 54.0 ft-lb (73.1 Nm)Torque (at the motor) 8.7 ft-lb (11.7 Nm)Rear wheel diameter=12.5”, Gear ratio=6.25:1,
Vehicle weight= 600 lb (272 kg)
VIP =
wTTwN
ωω
==
IKT T=
T
w
KNT
I⋅
=
Electric power formula; P=power, V=voltage, I=current.
Gear ratio: Tw=required wheel torque, T=motor torque, ω=motor angular velocity, ωw=wheel angular
velocity
Motor torque: KT=motor torque constant
Relationship between current and wheel torque.
Peak power and torque required to achieve the acceleration requirement.
28 April 2006 Team 4/5 Slide 19
20 Mile Drive Cycle MPGGE20 Mile Drive Cycle MPGGE
With 20 mile drive cycle:20 miles / 1.072 kWh = 18.7 mi/kWh501.2 mpgge (w/ 80% efficiency)
28 April 2006 Team 4/5 Slide 20
Range TestRange Test
Full performance capability- Accel. spec: 22.1 ft in less than 3 sec- Able to ascend all grades