Four-stroke engines have a separate reservoir for oil. Gasoline engines intake both air and fuel into cylinders. Compression a. Diesel engines compress air only. Gasoline engines compress both air and fuel within the cylinders. Ignition a. Diesel engines ignite the air-fuel mixture spontaneously, due to the heat of compression.
Gasoline engines ignite the fuel-air mixture with a spark from the spark plug.
Some diesel engines remove exhaust with a blower in addition to removing it with the upward motion of the piston. C. Basic design concept 1. A two-stroke engine utilizes one revolution of the crankshaft between each power impulse. This engine completes all four of the steps of the Otto cycle in only one revolution of the crankshaft. Some overlap of the intake and exhaust parts of the cycle occur on a ported two-stroke engine such as a small chain saw or leaf blower.