environmentally-friendly technology they think of hybrid cars and fluorescent light bulbs. These two items are so well-known because of their prevalence in today’s world. It makes sense to develop cars that get sixty MPG’s, just as it makes sense to produce light bulbs that draw 14 watts. After all, who can get by without cars and light bulbs? Green-thinking companies know that the best products to produce are the ones that are most popular. Still, this doesn’t mean that the power supply in your computer or the watch on your wrist shouldn’t be energy efficient. If it’s possible to design it that way without too much an increase in production cost, then why not? This is the thinking behind the Society of Automotive Engineers’ Clean Snowmobile Challenge. Snowmobiles aren’t nearly as plentiful on this planet as cars, but they do have access to some of the most environmentally pristine (and sensitive) areas on the globe. Thus, steps should be taking to minimize their environmental impact. It used to be that snowmobiles were loud, clunky machines that had little in the way of pollution control or efficiency. This has changed somewhat, with some current snowmobiles using 4-stroke engines and fuel injection. Still, compared to cars, little effort goes into making snowmobiles energy efficient and clean. The goal of SAE’s Clean Snowmobile Challenge is to show that this can not only be done, but that it can be done easily. Engineering colleges from across the country compete in the event, which is held in March in Michigan. I’m part of the University of Maine’s clean snowmobile team, and in the rest of this article I’ll share what I have learned on the subject. The first two topics discussed are useful if you’re looking to buy a moderately clean snowmobile right off the lot, and the rest are useful if you want to know what the next step is beyond factory condition. A good measure of a vehicle’s “greenness”, so to speak, is the amount of pollutants it releases to travel a certain distance. The lower the number the better. This can be affected by a number of factors, some of which are the quality of the combustion in the engine, the type of fuel being burned, and the fuel economy (efficiency) of the vehicle as a whole. What I’ve found is that it isn’t too hard to clean up a snowmobile with current technology; it just takes a little time. 4-Stroke Engines When selecting a snowmobile to work with, we at UMaine went with one that already had a 4-stroke engine. 2-stroke engines can be sloppy with how they handle the intake and exhaust gasses, and thus are generally worse for the environment than 4-strokes (this is the reason why no cars today are 2-strokes). Still, plenty of snowmobiles are sold with 2-stroke engines. Since there is no way to turn a 2-stroke engine into a 4-stroke, the only option for a 2-stroke snowmobile is to swap the engine out. But, if you’re buying a new sled, there’s no reason not to go with a 4-stroke right away. The option might be more expensive, but it’ll get better fuel economy and will be quieter than a 2-stroke machine. Fuel Injection Just as cars strayed away from 2-stroke engines, they have also moved away from carburetion. Fuel injection is the standard in cars because it allows for precise computerized control of the engine’s operation. Many snowmobiles are stuck in the past and are being sold with carburetors. It is possible to convert a snowmobile to fuel injection, but it’s an intensive process suited to those who love engines and long hours of greasy work. If you’re looking to buy a snowmobile, just get one that’s fuel injected right away. The performance and fuel economy boost will more than make up for the increased price. Weight Reduction Lighter=Faster, and more efficient. The lighter the snowmobile, the less the engine needs to work to get it moving. Weight can typically be shaved off in many areas, from body panels to batteries. Composite materials are very promising, as they have tremendous strength to weight ratios (many sports cars are made of carbon fiber). Aluminum alloys are also a good choice, and are less expensive than fiber solutions. Snowmobiles designed with aluminum alloys instead of steel will be much lighter and all-around better performers. Since lighter sleds are desirable from a performance standpoint, many manufacturers have taken steps to produce the lightest products possible, within reason. A little research before buying is always good, but generally today’s snowmobiles are lighter than those of a decade ago. If you’re looking to lighten up your current snowmobile, you could start with finding a smaller battery with the same specs as your current battery. It might be more expensive, but it’s a good way to lose a few pounds. You can also go about switching components such as handlebars with lighter alternatives, but in the end you probably won’t shave more than twenty pounds off the sled unless you start converting the body of the thing to carbon fiber. Catalytic Converters Catalytic converters (aka cats) are standard equipment on all cars and trucks. They sit in the exhaust path and are responsible for reducing the majority of pollution in the exhaust. They do this by lighting off unburned fuel (thus breaking hydrocarbons into water and carbon dioxide), breaking harmful nitrogen oxides down into nitrogen and oxygen, and oxidizing carbon monoxide to form carbon dioxide. Because the regulations are rather lax on off-road vehicles as compared to regular cars, snowmobiles are not required to have cats installed. Still, if you can weld or if you know someone who can, you can install a cat on a snowmobile. This simple addition will slash the snowmobile’s emissions, and it probably won’t cost that much to do (you might be able to get a small converter out of a junkyard for twenty bucks). This is by far the simplest and most effective modification, and it’s a wonder why snowmobile manufacturers don’t incorporate catalytic converters into their designs. Advanced Computer Control One of the things that can be done to improve engine performance is to upgrade the computer controlling the engine. This could be a hardware upgrade, a software upgrade, or both. Some cars automatically adjust the engine timing and fuel curves depending on the driver’s demand of the vehicle. Implementing this on a snowmobile would result in a computer that automatically switches between power mode and economy mode depending on the rider’s inputs. Alternate Fuels/Hybrid Designs Most internal combustion engines can burn fuels other than gasoline, and there’s no reason why a snowmobile couldn’t be made to burn a fuel like ethanol or natural gas. The UMaine clean snowmobile team is working to convert our snowmobile to E85 ethanol, as ethanol is a renewable fuel. Other snowmobile teams in the CSC have produced hybrid snowmobiles that get double the mileage of traditional machines (think Toyota Prius). If Toyota can produce a hybrid car, then the snowmobile companies surely could design a hybrid snowmobile. The market for such a machine would be tremendous, as there aren’t many places to refuel when you’re riding in the middle of nowhere. Conclusion There are many ways in which a snowmobile can be made more environmentally friendly, although most of them are not bothered with by manufacturers. Simple modifications like adding a catalytic converter and switching to a lighter battery can be done in one’s own garage. However, some new snowmobiles, such as carbureted 2-strokes, are just too far gone from the start. The EPA figures that ten percent of vehicular pollution comes from off-road vehicles, and it’s surprising that regulations haven’t been tightened to control emissions on these vehicles. If college students can modify a snowmobile to reduce its emissions by 70%, then why shouldn’t the manufacturers take action? If you plan to purchase a new snowmobile, I recommend going with a fuel-injected 4-stroke. It’ll be much quieter than a 2-stroke as well as cleaner. From there, welding a catalytic converter in-between your engine and muffler would further slash emissions, but this of course isn’t an option for everyone (it’ll probably void the warranty). For the gritty technical information on clean snowmobiles, please check out our website. Note: Although the following deals with snowmobiles, the information can be applied to other off-road vehicles, such as dirtbikes, ATVs, and jet skis.