Sub:-Elements of Mechanical Engineering

Topic:- Heat Engines

Shroff S.R. Rotary Institute Of Chemical Technology (Managed by Ankleshwar Rotary Education Society ) Approved by AICTE, New Delhi, Govt. of Gujarat & GTU Affiliated

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.

Elementary Heat Engine

Classification of Heat Engines

• External combustion engines

• Internal combustion Engines

Heat Engine Cycles

1. CARNOT CYCLE

• 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.

Carnot cycle processes

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.

RANKINE CYCLE

OTTO CYCLE ( constant volume cycle )

P-V and T-S diagram for Otto cycle

Application

DIESEL CYCLE

P-V & T-S diagram for Diesel cycle

Application