Submitted by Anonymous on Thu, 06/12/2008 - 20:40
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Greenland Atmospheric Studies

Craig -

This is Ethan - the advisor for the electric snowmobile project from the University of Wisconsin - Madison.  I just wanted to write and say hello - it's been a week since I got home and I miss Summit already.  I really enjoyed helping out with all the projects and wish I were still there - a week was not long enough! 

I've been reading your updates every day and especially enjoy reading about the research and seeing the lunch and dinner menus.  Even though I wasn't able to stay and help out, I really appreciate that all the blogs let me keep up with what is happening.  I even check the web-camera every day to see if I can see anyone working.

I don't think we got to go over how the electric snowmobile worked before I left.  Sorry we didn't get a chance to do that - I wanted to but the time just went by so quickly.  If haven't yet had a chance to try it out, but sure to ride it around while you're there.  It's probably the most fun snowmobile for 200 miles around!  For all the planning and coordination that it took to get it up there, I hope it is getting used every day!

Do you ride snowmobiles at all in Montana?  The early years of the Clean Snowmobile Competition took place in Wyoming, at Flagg Ranch (just outside Yellowstone) and Jackson Hole. 

Best wishes,

Ethan

Fri, 06/13/2008 - 14:57

Kristin Timm

I was also really curious about the electric snowmobile when Craig was talking about it during the Live from IPY! event this week.Perhaps you would be able to send Craig a "guest journal" describing the snowmobile-- I am curious how it works at those temperatures. It would be great if we could run something like that in Alaska.
Kristin  
 

Fri, 06/13/2008 - 16:44

Craig Beals

Ethan, good to hear you made it home safely!I am going to feature your snowmobile in a later journal, but for now I would like to open this forum up to you!  I have as many questions as everyone else so maybe you can help us out.
Feel free to give us any/all information about the snowmobile and I will learn along with those folks reading this topic.
If anybody has questions for Ethan about the electric snowmobile that the team from University of Wisconsin - Madison built and sent up to Summit Camp, just post them here and I will see that they get to Ethan for answers.
Correct me if I am wrong Ethan, but doesn't the snowmobile have one of the famed EV1 motors from GM/DELPHI?
Craig 

 

Thu, 06/19/2008 - 11:34

Ethan Brodsky

Craig -It's great to hear from you. It was a long flight home - we took the ski-equipped Herc back from Kangerlussuaq to New York, so it was a 7.5 hour flight instead of the 5 hour flight up there (the planes with skis fly much slower). After that I still had to fly home to Madison on a "normal" commercial airline. It was weird to again be in an airplane that was quiet enough to have a conversation without yelling.
I could write for hours about the electric snowmobile, but I'll try to keep it somewhat brief. I'm a scientist for the Medical School at the University of Wisconsin - Madison. I'm also the volunteer assistant advisor for the electric snowmobile project. The sled was mostly built by college students either as part of a senior design class, a for-credit independent study class, or as an extracurricular volunteer activity. UW-Madison is extensively involved in student automotive design competitions - aside from the snowmobile projects (both electric and engine-powered), we also do Challenge X (hybrid-electric SUV), SAE Mini Baja (off-road "dune-buggies"), Formula SAE (race-cars), and hybrid Formula (hybrid-electric race-cars). All these projects involve building prototype vehicles every year, and they're all done mostly by undergraduate students at our school.
The Clean Snowmobile Challenge was started in 2000 as a collaboration etween the Society of Automotive Engineers (SAE), the Montana Department f Environmental Quality (DEQ), and Teton County (Wyoming) Board of Commissioners. The goal was to uilt a clean and quiet snowmobile that could be used for touring national arks with reduced environmental impact - less pollution and less noise to disturb animals and other trail users and neighbors. You'll remember that noise and pollution from snowmobiles at Yellowstone was a major issue in he news around that time.
The competition typically involves 10-15 colleges and universities in the US and Canada and lasts 3-5 days. The first few years it was held just outside Yellowstone (I miss those days!) and later it was moved to Houghton, Michigan. It really has been a showcase of innovation - with many impressive technologies seen there several years before they were available from industry in production snowmobiles.
The competition started out only involving engine-powered sleds. The all-electric category was added in 2006 at the request of the National Science Foundation (NSF), with the goal to encourage the development of zero-emissions utility sleds, specifically for use at Summit Camp. The competition scoring awards points for useful characteristics like long range and high towing capability, as well as some "fun" things like acceleration and handling. There's also a lot of points involved in written reports and presentations. We won the competition this year and the NSF asked to borrow our sled for the summer to support the projects going on at Summit.
The sled is powered by Lithium-ion batteries. They're actually not anything exotic - it's likely that some readers here have the exact same batteries in your home. The battery pack is made up of 84 modules of Milwaukee Tool V28 batteries - the same batteries used cordless power tool. Twelve modules in series makes a 336 Volt "string" and we have seven strings in parallel to get the range and power we needed.
Li-Ion batteries are very good from an "energy density" standpoint - they can store a lot of energy in a small space with minimal mass compared to other technologies like Lead Acid (Pb-Acid) or Nickel-Metal-Hydride (NiMH). Weight is always a major consideration when trying to design efficient vehicles, especially a snow machine that will sink in to the snow if it is too heavy. Even in cars, reducing weight is a surprisingly good way to improve fuel economy.
In response to Kristin's question, Li-Ion batteries also perform well in the cold - remember that your cordless drill still works just fine in the winter. We have test data from the manufacturer down to -20 C, and one of the things we hope to learn this summer is how they work even colder. We don't really see any loss in power - the sled is substantially overpowered as it is, but there is definitely a loss of range and we will study are studying it this summer to determine how significant this is.
The motor for the sled is indeed from the famed GM EV1. We got the motor from Delphi, which was formerly a part of General Motors. They had been using it for testing in a lab and it was no longer needed - I don't believe that this specific motor was ever actually in a car, though it is possible. We also have an real operating EV1 on campus, which was donated by GM for display purposes, but we have restored it to full function and we use it for testing new systems and for public-relations activities like car shows and media visits.
The EV1 motor is an amazing machine - even though it was designed 15 years ago, it rivals the performance of the modern motors. It is very efficient and, since it's liquid-cooled, it can make a lot of torque in a very small package (air-cooled motors are usually much bigger for a equivalent level of power). We've used them in a number of different projects over the years and this motor was actually a "leftover" component that had been sitting in storage "waiting" for a project like this.
The motor is coupled directly to the track using a chain in a chaincase - there's no belt or clutch like in a typical gasoline-powered snowmobile. This makes the electric drive very efficient and also very simple, compact, and reliable. The sled can be charged by plugging it into a regular wall outlet - it can be recharged in 3-4 hours.
At competition, the sled achieved a range of 19.6 miles. Our original goal was 30 miles, but we realized early on that this wouldn't be practical, and our revised goal was to make it 20 miles at competition. We came very close! This was with warm conditions on very hard-packed snow with a single rider - the best conditions for going a long distance. At Summit Station, where it is colder, the snow is softer, and we are often pulling 1500 pounds of personnel and equipment, we are only seeing a range of about 7 miles. This is enough for many tasks around camp, but not enough for some of the longer trips that researchers want to do. We are hoping that we might allow a longer range after we study how the batteries are performing in the cold weather there - discharging them too deeply can ruin them, so we want to be very conservative at first.
You might wonder why it's so difficult to build an electric snowmobile that can go, say 100 mile on a charge. Consider that gasoline has an energy density of around 12 kW-hr/kg, while the lithium-ion batteries we use are less than 0.1 kW-hr/kg. This means that, to match the range of a typical gasoline-powered snowmobile with 10 gallons of fuel, we would need 2000 lbs of batteries (assuming an IC engine efficiency 25%). Clearly this would not be very fun to ride, so it's just not practical to build electric snowmobiles with range comparable to that achievable with liquid fuels. One other thing to consider is that we have 6.6 kW-hr of total energy on the sled - that's only enough to run a 100W light bulb for almost three days (and it would cost only $0.66 to charge at typical electrical rates in the US). A single gallon of gasoline can run the same bulb for almost 35 days if it were used 100% efficiently.
One other interesting fact is that, while the sled is there supporting the climate research projects at Summit, it's also an ongoing research project for us (I think that's pretty common at Summit - it seems like many of the research projects inter-relate and share data). We have a "data-logger" installed on the sled that records everything that is going on with the vehicle. Once per second, the sled its location (based on GPS), speed, "throttle" input, motor torque, battery voltage/current/temperature, and dozens of other items. The mechanic at Summit downloads these datalogs each week (by plugging in a USB memory stick) and sends them back to us, and we can use them to further "tune" the sled to increase range, as well as to write scientific publications about the sled, and to refine the design for next year.
If anyone wants to learn more about the project, we have a website at:
http://www.badgersnowmobile.com/and you can read about the Clean Snowmobile Challenge at: http://www.mtukrc.org/snowmobile.htm
Or feel free to post here and I'll be sure to answer. I check the blog every day to hear what is happening at Summit.
How has the sled been working since I left? The Summit Camp mechanic, Willow, emails me once a week with an update and a set of datalogs, but Irarely get to hear from the people actually using it.
I hope things are well at Summit!  Stay warm!
Ethan

Fri, 06/20/2008 - 09:06

Kristin Timm

Ethan, Thanks for the great description! Very Interesting! As an avid snowmobile rider here in Alaska (a.k.a. "snowmachine"- what we call them in Alaska), I think it would be amazing to see machines be cleaner and more efficient.
Have you ever heard of "Arctic Man"? You should try to bring some of your sleds to Alaska next spring!
Kristin

Fri, 06/20/2008 - 10:03

Ethan Brodsky

One of the guys who used to be on the Clean Snowmobile team went up to Summit Lake (almost like Summit Camp) for the Arctic Man this year and he said it was a great time. Electric snowmobiles can run with the best of them when it comes to acceleration and high speeds for short times, but range is always the limitation. We've talked about trying to enter some Snowmobile Drag Races - down in the lower 48 we have this bizarre sport of "Snowmobile Ashphalt Drags", where they race snowmobiles on pavement using metal skis with wheels. The top sleds can reach speeds of 150 mph, and 100 mph is not uncommon for regular sleds.
Arctic Man is a crazy competition which involves teams of two people and a snow machine. One person is the driver and one person is is skis or a snowboard. The skier goes down a huge hill, meets up with the snow machine, grabs a rope, is towed back up another huge hill, then skis down again. This all happens at speeds of 80 mph or more.
It sounds like the course is 5.8 miles long and the snow machine only has to do two miles of it, so it might actually be possible. Riding fast uses enormous amounts of energy (power scales far more than linearly with speed), especially when going uphill or when towing cargo. While we can go 20 miles at 20 mph, we'd be lucky to make 10 at 60 mph. We can easily do two miles at high speeds on level ground, but it's hard to say whether we could do it up a huge hill. It's certainly an intriguing idea, though I'd have to look at the topo maps to see if it'd be possible.
In early years of the Clean Snowmobile competition, the gas-powered sleds would compete in the "ultimate hill climb" event at Snow King Mountain in Jackson Hole. It was a very fun time to be out there and see and hear the 1000 hp custom-built hill-climb sleds!
If anyone is interested in sponsoring our entry into Arctic Man, let's talk!

Tue, 07/08/2008 - 15:36

Kristin Timm

Ethan, Thanks again for such a great explanation of the electric snowmachine and best of luck in your future work-- I'll keep my eyes open for sponsors for you and anxiously await the day the electric snowmachine is on the market. :) 
Kristin