This document discusses heat engines and their classification. It describes heat engines as devices that convert chemical energy to heat energy and then mechanical work. Heat engines are classified as either external or internal combustion engines. The document then covers common heat engine cycles like the Carnot, Rankine, Otto, and Diesel cycles. It provides details on the processes, diagrams, applications, and limitations of each cycle.

1. Shroff S.R. Rotary Institute Of Chemical Technology
(Managed by Ankleshwar Rotary Education Society ) Approved
by AICTE, New Delhi, Govt. of Gujarat & GTU Affiliated
Sub:-Elements of Mechanical
Engineering
Topic:- Heat Engines

2. What is Heat Engine?
• Heat Engine is the device which converts
chemical energy of fuel into heat energy &
this heat energy is utilized converting it to
mechanical work.
• A heat engine is a system that performs the
conversion of heat to mechanical
energy which can then be used to do
mechanical work.

3. Elementary Heat Engine

4. Classification of Heat Engines
• External combustion engines

5. • Internal combustion Engines

6. Heat Engine Cycles

7. 1. CARNOT CYCLE

8. • Carnot theorem says that No cycle can be
more efficient than a reversible cycle
operating between the same temperature
limits.
• There are some assumption made in the
working of the Carnot cycle.

9. Carnot cycle processes

10. Limitation of Carnot cycle
• The Carnot Cycle is Hypothetical ( something
that doesn't really exist )
• Practically it is not possible to neglect friction
between piston & cylinder.
• It is impossible to construct cylinder walls
which are perfect insulator.
• The output obtained per cycle is very small.

11. RANKINE CYCLE

14. OTTO CYCLE ( constant volume cycle
)

15. P-V and T-S diagram for Otto cycle

16. Application

17. DIESEL CYCLE

18. P-V & T-S diagram for Diesel cycle

19. Application