Table of Contents
What is a Heat Engine?
Before moving on to the heat engines (Classification of Heat Engines), let us first understand what is an engine.
An Engine is a device which converts one form of energy into another form.
Engines can further be divided into two types i.e. combustion engines and non-combustion engines. Examples of non-combustion engines are wind turbine and water turbine. Example of combustion engine is heat engine.
Now we will move on to the definition of heat engines.
A heat engine is a device converts chemical energy of fuel into thermal energy and utilize this thermal energy to perform useful work.
Types of Heat Engines
Heat Engines can be broadly classified into Internal and External Combustion Engines.
Internal Combustion Engines are the Engines in which fuel is burned inside the cylinder. Chemical energy of fuel gets converted into thermal energy which ultimately gets converted to mechanical energy.
External Combustion Engines are the Engines in which fuel is burned outside the cylinder and with the help of working fluid, brought to cylinder. Chemical energy of fuel gets converted into thermal energy which ultimately gets converted to mechanical energy.
Both the types of Heat Engines can be divided into Rotary and Reciprocating each. In Rotary Engines work is obtained from the heat with the help of Rotary devices (e.g. Turbines). In reciprocating Engines heat is converted to the work with the help of reciprocating mechanism (e.g. piston and cylinder).
Below are some abbreviation
IC – Internal Combustion
EC – External Combustion
Heat Engines
-
IC Engines
(i) Rotary
- Open Cycle Gas Turbine
- Wankel Engine
(ii) Reciprocating
- Gasoline Engine
- Diesel Engine
-
EC Engine
(i) Reciprocating
- Steam Engine
- Stirling Engine
(ii) Rotary
- Steam Turbine
- Closed Cycle Gas Turbine
Comparison between internal and external combustion engines
| Internal Combustion Engines | External Combustion Engines |
| Initial Cost is low | Initial cost is high |
| Can’t be operated by solid fuels | Can be operated by solid fuels |
| They require less space | They require more space |
Featured image source: By Jeff Dahl, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=3235265