Internal combustion engines generate heat by burning fuel directly inside the engine cylinders. The combustion process causes the piston to move, which in turn drives the crankshaft. Some examples of internal combustion engines include gasoline engines, diesel engines, and gas turbines.
External combustion engines generate heat by burning fuel outside of the engine cylinders. The heat is then transferred to a working fluid, which is usually water or steam. The working fluid expands and drives the piston, which in turn drives the crankshaft. Some examples of external combustion engines include steam engines, Stirling engines, and Rankine cycle engines.
Here is a table summarizing the key differences between internal combustion engines and external combustion engines:
| Feature | Internal Combustion Engine | External Combustion Engine |
|---|---|---|
| Combustion process | Fuel burns inside the engine cylinders | Fuel burns outside the engine cylinders |
| Working fluid | Air and fuel mixture | Water or steam |
| Piston movement | Driven by combustion | Driven by the expansion of the working fluid |
| Examples | Gasoline engines, diesel engines, gas turbines | Steam engines, Stirling engines, Rankine cycle engines |
In general, internal combustion engines are more efficient than external combustion engines. This is because the combustion process takes place directly inside the engine cylinders, which reduces heat loss. Additionally, internal combustion engines can operate at higher temperatures than external combustion engines, which also improves efficiency.
However, internal combustion engines also produce more emissions than external combustion engines. This is because the combustion process produces exhaust gases, which contain harmful pollutants such as carbon monoxide, nitrogen oxides, and particulate matter. External combustion engines, on the other hand, do not produce exhaust gases because the combustion process takes place outside of the engine.
Overall, internal combustion engines are more efficient but produce more emissions, while external combustion engines are less efficient but produce fewer emissions. The choice of engine type depends on the specific application and the trade-offs between efficiency and emissions.
