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 EnginesJesse SopkoTED 346Dr. Kallis

2. Facts2 Strokes per cycle of the engineIntake and exhaust are performed simultaneouslyIntake occurs at the end of the power stroke Invented by Dugald Clerk in 1881Fires on every revolution of the crank shaftLight weight and simple

3. Positives and NegativesPositiveNegativeLight WeightSimpleMore powerful than four stroke engines of equivalent sizeHigh power to weight ratioInefficientTerrible polluterLarge amount of unused fuel is expelled

4. How it worksIntake: 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. ExamplesDirt Bike Lawn mowersOutboard enginesChain sawsLine TrimmersJet SkisSnowmobilesModel Air PlanesLight MotorcyclesGo cartsUltra lightsScooters

6. QuestionWhere have you used a two stroke engine before?