The Otto Cycle

Jonathan Cheung4M-F

Background Information:• The Otto cycle is commonly known

as the four-stroke cycle used in internal combustion engines

• Invented by Nikolaus Otto in 1876

• Most commonly used for automotive and industrial purposes today

• Examples: Conventional gasoline, petroleum, and diesel engine in cars, trucks, and generators

The Process of the Cycle:

1. Intake stroke

2. Compression stroke

3. Ignition/Explosion

4. Power Stroke

5. Valve exhaust

6. Exhaust stroke

Intake Stroke Compression Stroke

Ignition/ExplosionPower StrokeExhaust stroke

Starting Position

Advantages of an Otto Cycle Engine:

Drawbacks:

• Relatively good thermodynamic efficiency• Relatively inexpensive to maintain and build • Excellent power-to-weight ratio • Good reliability

• Requires more moving parts and manufacturing expertise

• Engine is usually larger and heavier than a two-stroke engine or rotary engine of comparable power output.

Conclusion:• The Otto Cycle continues to be an integral and effective

combustion cycle amongst many engines because it provides excellent efficiency and power output.

References:

• http://auto.howstuffworks.com/engine.htm

• http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/InternalCombustion.htm

• http://en.wikipedia.org/wiki/Otto_cycle

• http://www.keveney.com/otto.html