SAE Formula Hybrid Competition

[Meatstick62]

So I just got back from the 2008 SAE Formula Hybrid competition at New Hampshire Motor Speedway yesterday. My team from school (Embry Riddle Aeronautical University) brought our car back to defend our title as national champions.

The Car:

The car is a hybrid gasoline-electric race vehicle that is powered by a 248cc internal combustion engine originally out of a Kawasaki Ninja making 36 HP at 11,500 rpm. The car utilizes an 18 HP electric motor that makes around 200 ft/lbs of torque at 1,250 rpm. The car has two capacitor banks each holding 25 Maxwell Ultracap capacitors. The frame is 4130 steel tubular chassis. The rear end is comprised of a structural transaxle that houses a rear differential from a Polaris ATV and the computer controlled, electronically actuated CVT. The front suspension is tubular and the rear a-arms are made of carbon fiber with nomex honeycomb cores. The total vehicle weight is 583 pounds wet. Our car was the lightest.

The Build

We have been designing and building the car for the past 7 months or so. We simplified our design and put the car on a massive weight reduction program. We used more composite materials and eliminated a lot of mechanical linkages, chains, and gears from our drivetrain. The design side began after last year's competition. The suspension, transaxle, and wheels wheels were designed, tested, and fitted in CATIA as were additional elements that will be incorporated into the design in the future but were unable to be included this year; these include a composite monocoque, front carbon fiber a-arms, and custom front wheels.

Nearly all of the components were constructed by us in our workshop and in our machine shop. The custom wheel centers, transaxle, CVT housing, and suspension uprights were all machined in-house on our Haas CNC machines.

We had many late nights in the shop and really got hectic as it came closer to competition. We were actually doing some final construction the night before the competition in the parking lot of the hotel. We were even wet-sanding and painting the nose cone in the bathroom that night. The body doesn't look at nice as last year's (it was a beautiful professionally painted full body last year) but the car performed much better.

The Competition

There were 16 teams at the competition including: Embry Riddle Aeronautical University (my team), Yale, Dartmouth, Illinois Institute of Tech., University of Vermont, McGill University (from Canada), Tufts University, NC State, University of Wisconsin, University of California, National Chiao Tung Univ. (from Taiwan), California Polytech, Florida Tech, Drexel University, and Moscow State Tech.

The competition included various events:
-one 75 meter acceleration event utilizing the electric motor only
-one 75 meter acceleration event utilizing the hybrid system
-an autocross competition
-a 22km endurance race
-a design presentation and sales pitch

We completed the electric acceleration run in 8.8 seconds and the hybrid run in 7.7. We were third in the acceleration test behing McGill and Dartmouth. We came in second in the autocross with the time we set in our first run but did not want to waste fuel to attempt to better it (we only get a little over a gallon of fuel for the whole competititon). We completed 32 of the 40 laps of the endurance race before our oil catch can overfilled and leaked some oil onto the track. We were told that we could not come back onto the track after we had been black flagged so that ended that event for us. We made the design finals and won for the best design in the competition.

Overall we were second in the points. Had we finished the endurance we would have won the whole thing. McGill ended up edging us out though for the second year in a row, but we have a lot more changes in store and a lot of room to improve. At least we can say that we're NATIONAL CHAMPS :thumbsup:

Pics:

Other Entrants:

McGill

Dartmouth

Yale

University of California

Illinois Institute of Technology

Wisconsin (sorry, no full shot)

Feel free to ask any question. I'll try to answer them as best I can.

[magic_hobo]

Maybe it's just the size of the car, but you guys have a huge box!

Also, I'm jealous of your haas action

Machining my stuff takes forever. Stupid ass trak POS mills

[Meatstick62]

yeah, our plenum was somewhere around 2.5 times our engine displacement. We had some problems with our airbox last year so we made sure we had one that would not choke the engine. Plus that was made during crunch-time (a few days before comptition) so it isn't th prettiest and the design wasn't optimized/tested at all. That's what next year is for.

[magic_hobo]

I meant your Al rear box structure

[Meatstick62]

oh, our transaxle casing? that was a nightmare to machine. many many late nights/early mornings. Each side took well over 20 hours to machine, the bigger sides took nearly 30. We could have just written the G-code for it and let the machine go at it, but we had limited time and messing up a piece due to faulty code 20 hours into a 24 job would be terrible. We had to do it in segements and watch the machine very closely to make sure it wasn't making any mistakes and ruining our parts.

[magic_hobo]

Quote, originally posted by Meatstick62 »

oh, our transaxle casing? that was a nightmare to machine. many many late nights/early mornings. Each side took well over 20 hours to machine, the bigger sides took nearly 30. We could have just written the G-code for it and let the machine go at it, but we had limited time and messing up a piece due to faulty code 20 hours into a 24 job would be terrible. We had to do it in segements and watch the machine very closely to make sure it wasn't making any mistakes and ruining our parts.

That's about the same amount of time I spent on ours... hopefully I can get the new one machined on the 3-axis haas. The ability to close the door and walk away is awesome

[Meatstick62]

Yes it is, at least when you're confident that your code is correct. You said "our" casing, are you on an FSAE or SAE FH team?

[flyinglizard]

How much voltage does the motor run on? Does it goe thru the variable drive also? Who did the actual engineering? Voltage, fuel .etc. Roll centers, camber gain, polar moment, What is the fuel burn rate/mpgetc. How about a turbo diesel running 4 motors at the wheels?
Can the CVT run a car? Could you build a rear axle for a VW, with two motors, driving the wheels, and than take two pistons out of the standard engine? Put the battteries in the back seat and the fuel in the trunk.. MM

[Meatstick62]

I am not sure what voltage we ran through the motor, I want to say 128 but I am not sure.

All of the systems were engineered by upperclassmen and senior team members at our university. They spent a good deal of their summers as well as their fall semester designing their systems and running calculation, doing CAD modeling, etc. They actually recieve credits for doing the project as part of their senior design project.

As for a turbo diesel, the rules limit us to a 250cc motor which basically limits us to small motorcycle engines and any internal modifications or forced induction forces us to run a restrictor plate. If you know of any 250cc turbo diesel bike engines, please let us know And as for using 4 hub mounted motors, that would be quite a feat and would actually be very hard to accomplish while maintaining a low vehicle weight.

CVT technology is being implimented on full-sized road vehicles today so it is possible to run a similar design on a road car, but this particular one would not work so well.

A rear axle with two electric motors? What you seem to be describing would not fit within the rules of this competition at all, but that's not to say that you couldn't build what you are describing.

[MuranoCVT]

Hey I was just checking up on your post. Looks like an interesting competition. I wanted to look at the presentation board pictures you took more closely. Do you think you have the actual data in the form of a pdf or something so that I can read what the numbers are?

[Meatstick62]

no I don't, sorry. I'll see if I can get my hands on them, but it may take a while.

[MuranoCVT]

Thanks, I appreciate your consideration.

[Alexis_B]

First week of May, when colleges and universities gathered together in Louden, NH for the Formula Hybrid International Competition. It was unique in that all the vehicles in the race were student-designed and built. The function was a recruiting forum for automakers seeking engineers.