The term "engine cycle" typically refers to the sequence of events that occur within an internal combustion engine during one complete operation. There are several types of engine cycles, but the most common ones are the Otto cycle and the Diesel cycle.
Otto Cycle: This is the cycle used in gasoline engines. It consists of four strokes:
- Intake Stroke: The intake valve opens, allowing the air-fuel mixture to enter the combustion chamber as the piston moves down.
- Compression Stroke: Both intake and exhaust valves close, and the piston moves up, compressing the air-fuel mixture.
- Power Stroke: When the air-fuel mixture is compressed, a spark plug ignites it, causing an explosion that drives the piston down, producing power.
- Exhaust Stroke: Finally, the exhaust valve opens, and the piston moves up, pushing the burnt gases out of the combustion chamber.
Diesel Cycle: This cycle is used in diesel engines and is similar to the Otto cycle but differs in the method of ignition. It also consists of four strokes:
- Intake Stroke: The intake valve opens, allowing air into the cylinder.
- Compression Stroke: The air is compressed highly, raising its temperature. Fuel is then injected directly into the cylinder near the top of the compression stroke.
- Power Stroke: The injected fuel ignites due to the high temperature of the compressed air, driving the piston down.
- Exhaust Stroke: The exhaust valve opens, and the piston moves up, expelling the exhaust gases.
These cycles are fundamental to the operation of internal combustion engines and are the basis for the efficiency and performance characteristics of various engine designs.
