Ryan Poulos Essays - Internal Combustion Engine, Tuned Exhaust

Ryan Poulos English 101 The Technology Of A Snowmobile Engine If you study and look at the history of a snowmobile engine, it has improved in many ways. I feel they have improved in two major ways. Number one being in performance, and number two they're more environmentally safe. In order for you to understand how this has happened, I will explain to you the engine of a snowmobile. A snowmobile engine is called a 2-cycle engine. This means unlike a 4-cycle which you would find in a car, 2-cycle engines fire every time the piston reaches ( top dead center ) T.D.C. Now if you look at a 4-cycle, or car engine it only fires every other time the piston reaches T.D.C. This advantage gives snowmobiles a great power to weight ratio. If you stop and take a look at a twin 600cc two cycle, it produces about 110 horsepower. Now if you take 600cc and convert it to cubic inches you get 36.6ci providing 110 horsepower. Further more we can compare that to a car and see the advantage. If you take a V8 305 cubic inches, you would figure out that it only has about 240 horsepower for all those cubic inches, and all that extra whight. That's how snowmobiles can be so powerful, but still so small and light weight. Unfortunately over the years people discovered a problem. Environmentalist thought if the piston fired every time it reached T.D.C., it had to be releasing gas and oil through the exhaust and into our atmosphere. This posed a problem for the snowmobile industry. But the companies researched and came up with three things. One is fuel injection so only the right amount of fuel is let in to the engine. This allows it to burn all the fuel, but is not very good for performance enthusiasts. So for performance machines they went back to carburetors, but cleaned the engines up two different ways. They started producing machines with variable timing, and variable exhaust. Variable Timing is done electronically by the more you advance the throttle to let the fuel in the engine, it electronically advances the timing so it fires faster to burn all the fuel faster and cleaner. Variable exhaust is a regulation of the exhaust port. This works by a slide or valve, that varies the shape of the port for true tuned exhaust. This helps burn all the fuel and gets the exhaust out the most efficient way. Another exhaust trick they use is right in the pipe itself. Today they use a megaphone pipe, to create a Venturi ( increases velocity) effect, that sucks out burned exhaust better than a normal pipe. Year by year snowmobile engines increase in performance and become more efficient and environmentally safe. This all goes together to benefit mankind in there needs and wants, and nature in its cleanliness so we can continue to go out and see nature's amazing beauty.