Two stroke engines complete the intake, compression, power, and exhaust strokes in one revolution of the crankshaft, using the crankcase as a pumping device. They are lighter and simpler than four stroke engines but are less efficient and more polluting. Common applications of two stroke engines include dirt bikes, lawnmowers, outboard engines, chain saws, jet skis, and snowmobiles.

1. 2 Stroke Engines Jesse Sopko TED 346 Dr. Kallis

2. Facts 2 Strokes per cycle of the engine Intake and exhaust are performed simultaneously Intake occurs at the end of the power stroke Invented by Dugald Clerk in 1881 Fires on every revolution of the crank shaft Light weight and simple

3. Positives and Negatives Positive Negative Light Weight Simple More powerful than four stroke engines of equivalent size High power to weight ratio Inefficient Terrible polluter Large amount of unused fuel is expelled

4. How it works Intake: Fuel and air mix is drawn into the crank case by vacuum and then into the cylinder. Compression: Fuel air mix is then compresses inside the cylinder. Power: Fuel air mix is ignited forcing the piston down exposing the exhaust port. Exhaust: The exhaust gases are forced out by the incoming fuel air mix.

5. Examples Dirt Bike Lawn mowers Outboard engines Chain saws Line Trimmers Jet Skis Snowmobiles Model Air Planes Light Motorcycles Go carts Ultra lights Scooters

6. Question Where have you used a two stroke engine before?