Four-stroke cycle (or Otto cycle)
1. intake
2. compression
3. power
4. exhaust
The is an engine in which the burning of a fuel occurs in a confined space called a combustion chamber. This exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. The defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause movement, for example by acting on pistons, rotors, or even by pressing on and moving the entire engine itself.
This contrasts with external combustion engines, such as steam engines, which use the combustion process to heat a separate working fluid, typically water or steam, which then in turn does work, for example by pressing on a steam actuated piston.
The term (ICE) is almost always used to refer specifically to reciprocating engines, Wankel engines and similar designs in which combustion is intermittent. However, continuous combustion engines, such as Jet engines, most rockets and many gas turbines are also internal combustion engines.
Internal combustion engines are seen mostly in transportation. Several other uses are for any portable situation where you need an non-electric motor. The largest application in this situation would be an Internal combustion engine driving an electric generator. That way, you can use standard electric tools driven by an internal combustion engine.
The advantages of these is the portability. It is more convenient using this type of engine in vehicles over electricity. Even in cases of hybrid vehicles, they still use an internal combustion engine to charge the battery. The disadvantage is the pollution that they put out. Not only the obvious, air pollution, but also pollution of broken or obsolete engines and waste parts, such as oil or rubber items that have to be discarded. Noise pollution is another factor, many internal combustion engines are very loud. Some are so loud, people need hearing protection to prevent damage their ears. Another disadvantage is size. It is very impractical to have small motors that can have any power. Electric motors are much more practical for this. That is why it is more likely to see an gas powered electric generator in an area that has no electricity to power smaller items.
History
Demonstration of the internal combustion indirect or suction principle. This may not meet the definition of an engine, because the process does not repeat. Early internal-combustion engines were used to power farm equipment similar to these models.The first internal combustion engines did not have compression, but ran on what air/fuel mixture could be sucked or blown in during the first part of the intake stroke. The most significant distinction between and the early designs is the use of compression and in particular of in-cylinder compression.