Presented by: Ashley Kelly Nathan Hansen Utah State University Electric Snowmobile Team

Overview Team Structure and Organization Objectives Comparison to Stock Testing and Energy Models Modifications Results Features of Final Product Future Work and Conclusion

Our Team Top row, left to right: Nathan Hansen (team leader), Denton Johnson, Byard Wood (faculty advisor), Scott Duhadway, Rob Silver, Paul Carpenter Front row, left to right: Nathaniel Hollingsworth, Ashley Kelly, Jed Jenkins, Merin Swasey, Steven Hanson, Ira Tibbits (Not pictured: Justin Maughan)

USU Electric Snowmobile Team Organization

Specifications StockModified Electric

Video Comparison of Stock vs. Electric Conversion (1997 Polaris Indy Trail 500)

Dyno Testing the Motor

Field Testing to Find Energy Requirements It was desired to know the energy requirement of the snowmobile at various velocities. This was accomplished by “drag testing” and gathering force vs. velocity data.

Modeling and Testing Energy models were built based on testing results and theoretical analysis. These were built using Mathsoft Mathcad, Microsoft Excel, and Intel FORTRAN 90/95 software. The use of this software made perturbation of possible solutions simple, and helped uncover the full scale effect of changing variables. Example of how energy models were used: Selection of drive train gear ratio, based on energy requirements of the snowmobile, discharge characteristics of the battery, and motor performance. Decisions were made towards meeting competition requirements.

Motor Testing: Series vs. Parallel The electric motor was rewired so that half of the four field coils could be run in parallel. This was done to reduce the amount of current that would be required at cruising speeds. The discharge rate of the batteries is the largest factor in electric snowmobile range, and any decrease in discharge rate leads to a logarithmic increase in range. Parallel Series

Testing Progression Major Milestones in Testing DatePurpose of TestChanges Since Last TestRange (miles) 11/28/2005rangefirst test of the year2.9 12/17/2005rangetrack tension optimized6.5 1/21/2006series/parallel testingmotor rebuilt, DAQ system - 1/25/2006rangedirect drive transmission9.5 1/26/2006rangeCVT transmission8.5 3/7/2006abuse and handlingsuspension rebuilt - 3/10/2006final pre-competition test - (total miles in testing this school year: 67.4 miles)

Modifications Many of the stock components in the snowmobile had to be redesigned to accommodate the requirements of electric vehicle parts. Possible designs were analyzed for performance and integrity. For example, the electric motor mount was rebuilt: Original electric motor mount: Yielded excessively under motor load Current electric motor mount: More appropriate to performance of motor

Suspension Modification was required in the rear suspension to handle additional loading from the batteries, and also to improve performance. The new suspension gives twice as much rear travel as the stock design did when loaded with batteries. Rider Comfort also increased.

User Friendly Batteries charge off of 120 V AC household current Charge time approximately 3.5 hours Easy quick disconnect to isolate high voltage system Drive and control just like a normal snowmobile Reverse Towing hitch Comfortable seat Stow compartments in seat Simple dash gauges to indicate speed, distance, current, voltage, and motor speed

Towing Capability and Utility SnoWatt towing a 1995 Jeep Grand Cherokee (4345 lbs)

Replaceable, Durable, and Low Cost Aftermarket parts are COTS (Commercial Off The Shelf) technology Motor: Advanced DC Controller: Curtis 1221-C Throttle: Curtis PB-6 Potbox Contactor: Kilovac Czonka Batteries: Universal Power UB12550 VRLA AGM Drive Train: Gates Polychain GT HTD All major parts engineered to provide an additional safety factor in endurance and performance Parts are readily available from a variety of suppliers Charging system is “plug and play,” using a standard power outlet All other components remain stock Cost TICA Cost of $ for fully electric conversion

Safety Not Pictured: Sealed, vented, and secured battery box In-line fuses in all electrical systems All major components are hermetically sealed Handle bar and tether kill switch Inertial kill switch (removed for performance handling) Anderson style disconnect for high voltage Warning lights to indicate connected high voltage High voltage contactor Additional guards for mechanical components

Performance Improvements: Zero on-site Emissions Substantial Reduction in Noise (no motor or clutch noise) Good Acceleration (0-500 feet in 10.9 seconds) Excellent Utility Performance Compromises: Range (9-12 miles) Weight (nearly 300 pounds heavier) Top Speed (reduced to 35 mph in direct drive system) Range and weight could be massively improved just by dropping in a different battery technology.

Future Work Weight Reduction! Reduction in energy requirements Friction in track Drive Train losses Noise reduction in mechanical components (track, chain) Improvements in battery technology Improvements in suspension and handling Much of efforts this year have been to establish a foundation that future teams may build on. Plans for next year’s CSC snowmobile include:

Conclusion Our strength is in simple design and solid engineering choices Unique electric approach is a quiet, clean, and practical solution Possible Markets: Scientists National Parks and Recreation Areas Utility Users (snowmobile equivalent of heavy duty truck) Environmentally conscientious snowmobilers Short range commuting The involvement of the National Science Foundation (summer 2006) and Yellowstone National Park lend great credibility and further the possibility of long term research into this exciting new technology.