University of Washington

Presented by Eric Yost

University of Washington

Electric Pontiac Fiero Project

General: To convert a gas powered ’88 Pontiac Fiero into an electric vehicle able to accelerate from 0–60 MPH in less than 5 seconds.

Specific: Design and integrate the drive train that best meets the requirements of the customer

Problem Statement:Problem Statement:

• Transmission• No transmissionNo transmission

Design Problems:Design Problems:

Dual 8” motors Single 9” motor

Permanent Magnetic Motors

Number and type of motors:

Design Problems:Design Problems:

Design Problems:Design Problems:Connecting the motors:

– PD Belt– Pulley and BeltPulley and Belt– Two-gearsTwo-gears– Three-GearsThree-Gears– ChainChain

Current Design:Current Design:

Simulation:Simulation:

Will be used to:– Determine manual transmission shift points for

maximum acceleration– Determine manual transmission shift points for

everyday commuting– Analyze specific components of the vehicle

Simulation Block Diagram:Simulation Block Diagram:

Simulation Components:Simulation Components:

• Driver• Controller• Motors• Coupling System• Transmission• Car Dynamics

Driver:Driver:

Assumes pedal to the metal

Controller:Controller:

Simulates the electric system

Controller II:Controller II:

Equation 1:• V = I R + Ke ω

– V: Voltage– I: Target Current ≈ 2000 amps– R: Motor Resistance ≈ 0.02 Ohms

– Ke: Motor Constant ≈ 0.25

– ω: Motor’s Angular Velocity

This voltage is capped at 196V

Equation 2:• I = (V – Ke ω) / R

This current is divided and fed to each motor

Controller III:Controller III:

Back EMF

Motor:Motor:

Equation for torque:

Coupling System:Coupling System:

Connects the two motors together

Transmission:Transmission:

Multiplies the torque and divides the RPM by the gear ratio

Car Dynamics:Car Dynamics:

Turns the applied torque into an acceleration and velocity

Car Dynamics II:Car Dynamics II:

Equations for Car Dynamics:– Force Equation:

– Power Equation:

Ideal Simulation Results:Ideal Simulation Results:Force Equation:

0-60 Time: 2.318s

Ideal Simulation Results:Ideal Simulation Results:

0-60 Time: 2.318s

Power Equation:

More Realistic Simulation Results:More Realistic Simulation Results:Force Equation:

0-60 Time: 4.170s

More Realistic Simulation Results:More Realistic Simulation Results:Power Equation:

0-60 Time: 4.170s

Future Addition:Future Addition:Tire SlippageTire Slippage

Two ideas of how to model tire slippage:– Realistic approach: If the torque is too high, the tires slip

– Ideal approach: The torque is capped before the tires can slip

Inaccuracies:Inaccuracies:

• Motor calculations• No tire slippage• Efficiencies • Drag constants• Modeling the driver

Questions?Questions?