The document discusses internal combustion (IC) engines. It defines an IC engine as a heat engine that converts the chemical energy from combustion of a fuel into mechanical energy. The combustion occurs inside the engine, with the expanding gases directly applying force to engine components. In contrast, external combustion engines perform combustion externally and transfer heat to the working fluid via a heat exchanger. Common IC engine components are discussed, along with the combustion process and applications such as steam engines.

1. IC Engines

2. IC Engines
• IC Engines  Internal + Combustion + Engines
• Internal – Inside
• Combustion – Burning
• Engine – Energy conversion device (Chemical Energy to
Mechanical Energy)
• Chemical Energy
• Energy stored in the bonds of chemical compounds
• Released during chemical reaction
• Mostly released energy in the form of “Heat”  Exothermic
reactions
• Example : Human body (Food  Movement)

3. Endothermic Reaction vs. Exothermic
Reaction

4. Mechanical Energy

6. Energy - Types
Definition: Ability to do the Work
Many forms of energy exist, but they all fall into two basic
categories:
• Potential energy
• Kinetic energy

7. Combustion Requirements

8. Fuel
• Material such as coal, gas, or oil that is
burned to produce heat or power.
• Hydrocarbon
• Hydrogen – Highly Inflammable, Oxygen –
Supports combustion, why Water (H2O)
not a flammable and used as fire
distinguisher ?

9. Combustion Engines
Internal Combustion Engines
• An internal combustion engine (ICE or IC
engine) is a heat engine in which the
combustion of a fuel occurs with an
oxidizer (usually air) in a combustion
chamber that is an integral part of the
working fluid flow circuit.
• In an internal combustion engine, the
expansion of the high-temperature and
high-pressure gases produced by
combustion applies direct force to some
component of the engine.
External Combustion Engines
• An external combustion engine (EC
engine) is a reciprocating heat
engine where a working fluid, contained
internally, is heated by combustion in an
external source, through the engine wall
or a heat exchanger.
• The fluid then, by expanding and acting
on the mechanism of the engine,
produces motion and usable work.
• Examples: Steam Engines, Stirling Engine

10. Comparison of IC Engine Vs. EC Engine
Parameter IC Engine EC Engine
Combustion of fuel Takes place inside the cylinder Takes place inside the cylinder
Fuel /Working Fluid Petrol/Diesel/Gas, etc Steam
Space Requirement Less High
Capital Cost Less High
Engine Starting Easy Little difficult
Thermal Efficiency High Low
Fuel Cost High Low

11. Combustion Engines- Applications

12. Steam Engine

13. IC Engine Working

14. IC Engine Components