prototype review 2 - ohio university · 28 april 2006 team 4/5 slide 17 voltage constant 72 rpm per...

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


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


H3R Powertrain H3R Powertrain Component OverviewComponent Overview

Briggs and Stratton Etek motor4 VRLA Panasonic batteriesNavitas TPM400 controllerChain drive, 6.25:1 gear ratio


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


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


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)


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


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


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


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)


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


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


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


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


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


Questions?Questions?


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


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.


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)


Range TestRange Test

Full performance capability- Accel. spec: 22.1 ft in less than 3 sec- Able to ascend all grades

prototype review 2 - ohio university · 28 april 2006 team 4/5 slide 17 voltage constant 72 rpm per...

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