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An Engine is a mechanical device that is used to convert one form of energy to another. The type of engine about which we are going to study in this article converts heat into work.
On the basis of location of actual combustion of fuel, engines can be classified into two types.
One is internal combustion engine (ICE) and another one is external combustion engine.
In this article we will limit our discussion to internal combustion engines.
What is an internal combustion engine?
It is quite obvious from the name that in internal combustion engines, fuel is burned inside the engine. Unlike external combustion engines in which fuel is burned outside the engine.
Most popular type of internal combustion engine which we see today is the engine which we use in our car and motorcycle.
We can easily note that we put fuel in these engines and that fuel gets burned inside the cylinder. Engine converts energy of fuel into power and releases exhaust gases of combustion process.
- Internal combustion Engine Working Animation
In the above animation we can easily understand working of an internal combustion engine.
Here, blue color denotes fuel and brown color denotes exhaust gases.
The most common types of internal combustion are
- Open cycle gas turbine
- Reciprocating internal combustion engine
- Wankel Engine etc.
Advantages of internal combustion engines
- Size of engine is very less compared to external combustion engines
- Power to weight ratio is high
- Very suitable for small power requirement applications
- Usually more portable than their counterpart external combustion engines
- Safer to operate
- Starting time is very less
- High efficiency than external combustion engine
- No chances of leakage of working fluids
- Requires less maintenance
- Lubricant consumption is less as compared to external combustion engines
- In case of reciprocating internal combustion overall working temperature is low because peak temperature is reached for only small period of time (only at detonation of fuel).
Disadvantages of internal combustion engines
- Variety of fuels that can be used is limited to very fine quality gaseous and liquid fuel
- Fuel used is very costly like gasoline or diesel
- Engine emissions are generally high compared to external combustion engine
- Not suitable of large scale power generation
- In case of reciprocating internal combustion noise is generated due to detonation of fuel
Types and applications of internal combustion engines
- Gasoline Engines: They are used for Automotive, Marine, Aircraft purposes.
- Gas Engines: They are used for Industrial Power purposes
- Diesel Engines: They are used for Automotive, Railways, Power, Marine purposes.
- Gas Turbines: They are used for Power, Aircraft, Industrial, Marine purposes.
Image source: By Zephyris – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10896588
While most of these are correct, in fact modern steam engines have a higher efficiency than internal combustion, whic is why they are used for power generation in stationary applications where the weight-power ratio does not matter (though in markets where time is a factor for changing power levels they are often supplemented with internal combustion, generally to offset the unpredictability of wind power)