In this article, we learn what is internal combustion engines, the types of internal combustion engines, and the comparison between internal combustion engines & Gas Turbines.
Internal Combustion Engines
Any machine which derives heat energy from the combustion of fuel (chemical energy of fuel) and converts part of this energy into mechanical work is called a heat engine.
These heat engines may be externally combustion type or internally combustion type.
In the case of external combustion engines, the combustion of fuel takes place outside the cylinder. For example Steam engines, steam and gas turbines, air engines, etc.
In the case of internal combustion engines, the combustion of fuel in the presence of air takes place inside the cylinder, and produced gases act on the piston to develop the power.
For example Pet-ml engines, diesel engines, gas engines, etc.
Internal combustion (I.C.) engines are commonly used in vehicles, locomotives, and in various industrial applications.
Types of Internal Combustion Engines
The types of internal combustion engines are classified as follows:
1. According to the cycle of operation
a) Four-stroke engines: In these engines cycle is a crank.
b) Two-stroke engines: In these engines cycle is a crank.
2. According to the nature of the thermodynamic cycle
a) Constant volume or Otto cycle.
b) Constant pressure or diesel cycle.
c) Partly Otto and partly diesel cycle or dual cycle.
3. According to the method of ignition
a) Spark Ignition (S.I.) engines: In spark ignition or petrol engines, an air-fuel mixture supplied by a carburetor is ignited by producing a spark.
b) Compression Ignition (C.I.) engines: In compression ignition or diesel engines air is compressed to higher pressure and in finely atomized form fuel is injected in the combustion chamber. Hence air-fuel mixture is ignited without producing a spark.
4. According to the number of cylinders
a) Single-cylinder engines
b) Multi-cylinder engines
5. According to the type of cooling system
a) Air-cooled engines: For cooling purpose air is used.
b) Water-cooled engines: Water jackets are provided around the cylinder to cool the engine.
6. According to the speed of engines
a) Low-speed engines
b) Medium-speed engines
c) High-speed engines
7. According to the lubrication method
a) Wet sump lubrication
b) Dry sump lubrication
c) Pressure lubrication
8. According to the fuel used
a) Petrol engines
b) Diesel engines
c) Gas engines
9. According to the field of operation
a) Automotive engines
b) Stationary engines
c) Locomotive engines
d) Marine engines
10. According to the arrangement of the cylinder
b) Horizontal engines: In these engines, the cylinder is in a horizontal position.
c) V-engines: In these engines, two cylinders are arranged at an angle connected to a common crank
d) Radial engines: In these engines 4 to 6 cylinders are placed radially and equally spaced and connected to a common crank.
e) Opposed cylinder engines: In these engines, cylinders are arranged on the opposite sides of a common crank.
f) Opposed piston engines: In these engines, a single cylinder houses two pistons, each of which drives a separate crank.
Comparison between Internal Combustion Engines and Gas Turbines
Internal Combustion Engines
1. For I.C. engines flywheel is required.
2. Control of fuel supply is easy.
3. Starting I.C. engines is very easy.
4. It produces fewer exhaust gases because the work developed is also less.
5. Costlier fuel is required for the operation.
6. I.C. engines cannot be driven at high speeds.
7. Low mechanical efficiency.
8. High thermal efficiency.
1. For gas turbines flywheel is not required.
2. Control of fuel supply is comparatively difficult.
3. Starting gas turbines is difficult.
4. It produces more exhaust gases because the work developed is more.
5. Low-cost fuel can be used for the operation.
6. Gas turbines can be run at high speeds.
7. High mechanical efficiency.
8. Low thermal efficiency.