FLORIDA INSTITUTE OF TECHNOLOGYCOLLEGE OF ENGINEERING

Design Presentation

Project: 2007 R.E.V. Team

Presented By:

Elizabeth Diaz Jason Miner Jared Doescher Josh Wales

Kathy Murray AJ Nick Dave Wickers Oliver Zimmerman

Project Scope:

• Design and Build an electric racing vehicle

• Promote community awareness of electric vehicles

•Electric Car designed to compete in SCCA Autocrossand Formula Hybrid competition

- Competing as “Hybrid-in-Progress” vehicle for one year only

- Electric Car designed to compete in Autocross, Acceleration and Endurance races

•Will meet requirements for the 2007 Formula Hybridcompetition and NEDRA race competition

Engineering Objectives:

• Acceleration from 0 to 60 mph in under 5 seconds

• Top speed of 80 mph

• Maximum power available between 20 and 40 mph

• Lightweight (under 650lb without driver)

• 15 minute battery life for continuous draw

Team Lead

Design Teams

Development Group Procurement Group Manufacturing Group

Integration Team

Chassis & Body

Chassis RedesignBody RedesignMounting PointsAeros/Ground Effects

Drive System

MotorDrivetrainControl SystemBattery SystemCooling SystemShielding System

Electrical

Battery Management InstrumentationData Transfer SystemPower Management

Vehicle Dynamics

Suspension SystemSteering SystemBraking System

Driver Interface & Ergonomics

Cockpit DesignSafety EquipmentDriver Interface

Team Organization:

Electrical Team:

Team Organization: REV Design Teams

Josh WalesAJ NickKathy Murray

Jason MinerDave Wickers AJ NickJared DoescherKathy Murray

Jason MinerAJ NickDave Wickers

Oliver ZimmermanDave Wickers

Drive System Team: Vehicle Dynamics Team:

Driver Interface Team:

Elizabeth Diaz

Team Lead:

Design Teams

Matt Reedy Valerie BastienAudrey MoyersKristi Harrell

Chassis & Body Team:

• Complete the car

• Create/Integrate Lithium-Ion pack

• More publicity– Autocross racing– More EV events– Local advertising

• Funding

Major Goals of the Team

Florida Tech REV

• Overall Length, Width, Height: 107in x 60in x 46in

• Wheelbase: 68.5in

• Front Track: 52in

• Rear Track: 50in

• Weight: 795lbs (without driver)

Design: Chassis

Engineering Specifications

• Static deflection – Less than .333”

• Torsional Rigidity – above -1500 ft-lbs/deg

• Wheelbase – between 60” and 70”

• Designed to fit 95 percentile person

• Withstand stresses under dynamic and static loading with factor of safety of 3

Design: Chassis

• Side Pods act as impact structure

• Upper side impact structure member attached too high to main hoop

• As requested by Formula Hybrid, new cross member had to be constructed to protect driver

Static Analysis

Deflection Analysis Static Stress Analysis

Max stress: 5361 psiFactor of safety:11.9

Max deflection: -.0098 inches

Dynamic Stress Analysis

Braking

• Using MSC ADAMS to get forces at A-Arm attachments•Braking ( 60- 0 in 3 sec)•Lane change at 50 mph

•60 mph radius turn of 343 feet•Applied loads in ANSYS to find stress

Cornering

Max stress: 22126 psi Max stress: 16159 psi

Analysis Changes: Chassis

Torsional Rigidity Analysis

•Constrained back of frame and added

forces to front hoop•Measured deflection

at nodes on hoop•Calculated Torsional

rigidity by:

)

2

21tan(

L

yya

Flk

4900 ft/lbs per degree

Manufacturing: Chassis

• Frame was constructed on campus• Weld analysis proved welds will hold• Intersections with many multiple welds were

hardest to cope

Lessons Learned: Chassis

• Have more than one designer on the chassis

• Design and analysis together• Consideration of weight

versus strength

• Allow 1” travel jounce and rebound• Achieve maximum tire contact at all times• Optimize handling

Suspension Design

• Non-equal, Non-parallel A-arms• Push rod actuated coil-overs• Variable dampers

Table 3.7: Front Suspension Geometry

Static Camber -1.5˚

Camber Gain in Jounce -.95˚/1"

Camber Gain in Rebound .89˚/1"

Caster 5˚

Kingpin Offset .915"

Kingpin Inclination 0˚

Toe In 0˚

Ground Clearance 2"

Static Roll Center 1.23"

Roll Center @ 1" Jounce -.18"

Roll Center @ 1" Rebound 2.65"

Front Track Width 52"

Table 3.8: Rear Suspension Geometry

Static Camber 0˚

Camber Gain in Jounce -1.05˚/1"

Camber Gain in Rebound 1.02˚/1"

Caster 3˚

Kingpin Offset 0.02"

Kingpin Inclination 0˚

Toe In 1˚

Ground Clearance 2"

Static Roll Center 1.34"

Roll Center @ 1" Jounce 0.4"

Roll Center @ 1" Rebound 2.75"

Rear Track Width 50"

Suspension Design Specifications

BELLCRANK POSITION CHANGE FOR CLEARANCE ISSUES

Front Suspension

COILOVER ACTUATION DESIGN

COILOVER ACTUATION BUILD

Rear Suspension

Roll Center

Shims between clevis

Suspension Adjustability

FRONT SPRING RATE ≈ 350 LB/IN REAR SPRING RATE ≈ 372 LB/IN

Suspension Spring Rates

• Nitrogen Charged• Adjustable damping in jounce and rebound• Preload adjustment• Cost effective

Dampers

Jupiter 5 by Risse Racing

Steering Geometry

• Rack and Pinion• Lower rear placement• Full Ackermann geometry

Testing and Improvements

• Final car setup and fine tuning – Ride Height– Camber– Toe

• Add anti-roll bars• Add sensors

• Check more thoroughly for clearance issues• Use proper bolts• Change clevis design

Lessons Learned: Suspension

Design: Differential

• Brute Force Kawasaki ATV front differential

• Limited Slip with a selectable locker

• 4.375 gear reduction

Differential & Mounting

•Tensile Yield Stress of Aluminum: 47000 psi•3/8” thick aluminum

•Max Von Mises stress: 33665 psi•Factor of safety of 1.3

•Instead of remanufacturing with 1/2” aluminum an additional mount was added•Max Von Mises stress: 25944 psi•Factor of Safety of 1.8

Differential & Mounting

• Warp 9” motor, 80hp peak, 140ft-lbs• 32.3 continuous horsepower (versatile)• 600amps, 144volts from Zilla 1K-HV (with power

conversion)• 2 min full throttle run time, 15min at 35mph• Top Speed 85mph @ 6000 rpm • Pic to PLC to LCD

Design: Electrical Integration

Power Source & Containment Area

Odyssey Battery,Model PC680

• Lead Acid Batteries 232lbs, 13.6 usable Ah (17ah, up to 80% discharge) at 192V (Nominal)

• 16 cells, cost approx. $1500• Odyssey PC680 Lead-acid batteries

• Diagonal Support tube thickness increased to .095” (full X)• Battery Layout

Strapped together then strapped to supportsPlexiglas to cover connections (with High Voltage Warning Label)Nomex fabric on walls and bottom for electrical insulation and fire protection

Power Source & Containment Area

Albright SW200 contactor

• Full High Voltage Accumulator Containment

Dual Contactors default to Open 3 Emergency Stop Buttons Fuse Backup High power lines outside Battery Area held in rubberized conduit

Ferraz-ShawmutFuse

• Motor, Battery, gear ratio combination was essential decision.

• Excel Spreadsheet used to compare and optimize. • Takes into account specs and calculates 0-60 time,

voltage drop, runtime, and more.• Final Configuration:

0-60mph in 4.5 seconds (calculated)

Design: Performance Calcs

Design: Brakes

• Design Criteria– Braking system that acts

on all four wheels and is operated by single control

– Two independent hydraulic circuits

• Alterations in Design– New master cylinders

were purchased due to a leak in the old ones

Design: Brakes

• Design Calculations– To optimize handling the front

wheels should lock up first in a full braking situation

• To ensure this a bias was applied to master cylinders

– Front 60% and rear 40%

– Full Braking from 60 mph• Calculated stopping distance:

124.73 ft

• Design Criteria– Must be able to hold the touch

screen– Comply with SAE rules– Designed to be as light as

possible while remaining rigid enough to protect touch screen

– Shaped for driver’s comfort

• Alterations in Design– Changed because of the

method of mounting provided from manufacturer

– Created a new wheel to be fully closed loop IAW SAE rules

Previous Design

Current Design

Design Changes: Steering Wheel

• Design Criteria– Structurally Rigid and

Reliable

• Previous Steering Wheel did not fit design criteria– Also did not need touch

screen for competition

Design Changes: Steering Wheel

• Design Criteria– Ergonomic to fit driver– Highly reliable

• Alterations in Design– Design Simplified to

increase reliability– More ergonomic for driver

Previous Design

Current Design

Design Changes: Acceleration Pedal

• Design Criteria– Must have a 5-point or 6-point harness– Driver Must Be Isolated from High-voltage– Front Impact attenuator– Side impact structure– Must have at least 3 Large Emergency Shut Off buttons

• How we meet/exceed criteria– We have a 5-point harness that corresponds to Formula SAE

regulations– High-voltage wires are isolated in Side Pods and conduit

outside of Side Pods– Impact attenuator fits FSAE regulations– Our Side Impact structure Approved Structural Equivalency– Two Emergency Shut off buttons on either side of roll hoop and

one on driver’s dash board, also one main switch– Hairball Controller Interface allows user to limit power

Design: Safety

Design: Safety

Safety Harness

Emergency Stop Switches

Main Switch

Safety Suit & HelmetHairball – Controller

Interface

• HRH-10/OX – 3/16 – 4.0 HexWeb Honeycomb • 7 – 1” layers separated by steel sheet• 650psi Typical Stabilized Strength• Designed to absorb K.E. of 945lb, 15mph car &

driver at less than 20G’s (capable of stopping greater mass than required by Formula Hybrid)

Design: Impact Attenuator

• Body covers from front tip back to the main roll bar

• Side Pods fully enclosed• Molded body to fit over front

shocks and allow room for the impact attenuator

• Floor and side panels around the motor to protect the motor from debris

Design Changes: Body

• Recommendations– Start Early– More than one committed

person involved

• Testing has been done for several different aspects of the car– Acceleration– Autocross– Endurance

• Testing still needs to be completed for– Braking

• Testing is also serving the purpose of acquainting the drivers with the handling of the car

Performance Testing

Performance Tests: Acceleration & Braking

• Tests were preformed to see if the car can reach the design specifications set with the higher weight

• These tests allow the drivers to learn the sensitivities of each of the pedal systems

Completed Testing Results• Max Speed of 67 mph• Test completed within 0.1 mile

Performance Tests: Autocross

• This testing is used to demonstrate that the car can fulfill the turning radius requirements that have been set

• Autocross testing is also used so that the drivers know how the steering will handle

Completed Testing Results• Slalom runs completed to test the suspension and steering• Resulted in sheered grade 2 bolts, all bolts replaced with grade 8 bolts

Performance Tests: Endurance

• The endurance testing serves the purpose of finding out how long the batteries will last under constant draw

• This section of the testing will also allow the team to find out how long it will take to charge the batteries during the halfway point of the endurance race at competition

Completed Testing Results• Time lasted : 20 minutes at 10 mph• Resolution: larger controller and more batteries

Testing: Conclusions

• The testing that has been performed on the car has shown that we meet the design specifications for – Turning Radius– Maximum power available between 20 and 40 mph

• We do not meet the requirements for– Lightweight (under 650lbs with driver)

• We expect to meet, but have not yet tested– Acceleration from 0 to 60 mph in under 5 seconds (4.5seconds –

calculated)– Top speed of 80 mph (85mph - calculated)– 15 minute battery life (at constant speed of 35mph)

Project Management:

Primary functions

• Budgeting

• Funding/Sponsors

• Scheduling

• Managing a Team

• Assigning Tasks

Vehicle Dynamics

PLC and Touch Screen

$13,265$13,265

Budget

Chromoly Tubing $86

Spherical Bearings $460

Brakes $160

Tires $680

Chromoly Tubing $740

Fiberglass $80

Shielding $180

Nomex $80

Miscellaneous $250

PLC and Modules $286

Touch Screen $810

Speed Sensor $55

PC Boards $150

00 Guage Wire $80

Master Switch $155

Contactor $240

Fuses $66

Miscellaneous $300

Safety Harness $180

Driver Accessories $430

Miscellaneous $200

$76Potentiometer

$700Differential

$1,440Lead Acid Batteries

$2,860Controller

$1,600DC Motor

Drive System

Battery Management Driver Interface

Chassis and Body

Budget:

Resources:

•Dr. Larochelle – Team Advisor

•Dr. Grossman – Team Advisor

•Larry Buist – Electrical Support

•Bill Bailey – Shop Supervisor/Welder

•John Amero – Machinist

•Bill Battin – Technical Support

•Stephanie Hopper – Lab Director

•Frank Leslie – Public Relations/EV Advisor

•USA

•Grassroots EV

•US Didactic

•Charles Whalen (FLEAA)

•Bob Steele Chevy

•FLEAA

•CV Restoration

•C2 Design

• Brevard Rentals

Sponsors: Personnel:Programs:

•Pro/Engineer Wildfire 3.0

•ANSYS

•ADAMS

•OrCAD

•EZ Touch – EZ Panel Enhanced

•EZ PLC Editor

•LabView

•PIC Basic

Resources

Recommendations:

• Scheduling

Design completion

Give ample time for testing

• Managing a Team

• Set goals high

• Keep the team going but give some time to relax

• Assigning Tasks

• Don’t overload one person to a task

• Assign tasks to the appropriate person

Lessons Learned

• Interdisciplinary cooperation- Start early with incorporation of electrical systems - Stay in communication- Introduce each other systems to the other group

• Leave enough time for testing and troubleshooting• Keep drawings updated as soon as something changes

Lessons Learned

Recycling of components-Cost saving-time savings

-Analysis-Production-Implementation

Examples-Rims-Shocks-Steering pinion gear-Seat-Wheel Brakes

Suspension:• Anti-roll bars• Data Logging

Recommendations:

• Keep the car fully electric • Run true performance tests• Keep electrical engineers on the team

• To Do:– Build Battery Management System– Check and Adjust Differential Mounting– Improve Real World Motor Performance– Locate Li-Ion/Li-Polymer Sponsor– Evaluate BMS (Battery

Management Systems) options

Future Improvements

Future Improvements

For Future REV Form• Schedule testing time on a real track• Reintroduce Lithium Ion batteries as power source• Reincorporate PLC control system• Expand on sensors

- Temp, speed - efficiency

• Increase Data collection for evaluation of performance

Future Improvements

For Future Formula Hybrid -Use IC as power generator-Use electric engine for propulsion-Reconsider Capacitors for rapid charging and discharging cycles-Redesign frame to fit all components

Questions?!?