How It Works Picture Advantages And Disadvantages Common Applications

1. Two-Stroke Motors How It Works Picture Advantages And Disadvantages Common Applications Click the screen to continue or click the arrows to go to a specific location. Exit

2. How It Works, Part I Two-stroke engines have one valve, the reed valve. This valve allows the air/fuel/oil mixture into the crankcase. The actual piston itself allows the air/fuel/oil mixture and burned gases into and out of the combustion cylinder. As the piston moves downward, it compresses the air/fuel/oil mixture in the crankcase. At the same time, the exhaust port is open and the compression from the piston causes most all of the burned gases to exit through the exhaust port. Title Exit

3. How It Works, Part II Once the piston bottoms out, the intake port is open and the pressurized air/fuel/oil mixture is forced into the cylinder. At the same time, the fresh intake charge forces out the last of the exhaust. The momentum of the piston drives it back toward the spark plug for the compression stroke. As the air/fuel mixture in the piston is compressed, a vacuum is created in the crankcase. This vacuum opens the reed valve and sucks air/fuel/oil in from the carburetor. Once the piston makes it to the end of the compression stroke, the spark plug fires again to repeat the cycle. Title Exit

4. How It Works, Part III Basically, the piston is doing three different things in a two-stroke engine: On one side of the piston is the combustion chamber, where the piston is compressing the air/fuel mixture and capturing the energy released by the ignition of the fuel. On the other side of the piston is the crankcase, where the piston is creating a vacuum to suck in air/fuel from the carburetor through the reed valve and then pressurizing the crankcase so that air/fuel is forced into the combustion chamber. The sides of the piston act like valves, covering and uncovering the intake and exhaust ports drilled into the side of the cylinder wall. Title Exit

5. Two-Stroke Engine Diagram Title Exit

6. Advantages Two-stroke engines do not have valves, which simplifies their construction and lowers their weight. Spark plugs fire once every rotation which gives them a bigger power boost. Two-stroke engines can work in any orientation. Two-stroke engines are lighter, simpler, and less expensive to manufacture. Disadvantages Lack of a dedicated lubrication system means parts wear faster. Two-stroke oil is expensive and a large amount is required for two-stroke motors. Two-stroke engines do not use fuel efficiently. Two-stroke motors produce a lot of pollution because they burn oil and there are no valves; unburned air/fuel can escape through the exhaust port. Advantages And Disadvantages Title Exit

7. Common Applications Although two-stroke engines are not very economical for cars, they do have many applications: Chain Saws Dirt Bikes Jet Skis Leaf Blowers Mopeds Radio-controlled Model Airplanes Small Outboard Boats Title Exit