Heat engine classifications and types

The petrol or oil engine, which is the source of power with which we are immediately concerned, is a form
of internal combustion ‘heat engine’, the function is the production of mechanical power from the chemical energy contained in the fuel.

Heat and work :

A quantity of heat is conveniently measured by applying it to raise the temperature of a known quantity of pure water.

The unit of heat is defined as that quantity of heat
required to raise the temperature of unit weight of
water through one degree , this quantity depending
,of course , on the particular unit of weight and the
temperature scale employed.

The internal combustion engine are Spark-ignition
engine (sometimes called gasoline,petrol engine,or
otto cycle engines , though other fuel can be used )
and compression ignition or Diesel engines .

Internal combustion engine start to be known when
Otto had developed the spark-igntion engine and when
Diesel invented the Compression ignition engine.

This website contains a general overview of the fundamental principles which governs internal combustion engine design and operation.

the emphasis here is on the thermodynamics,combustion physics and chemistry , fluid flow,heat transfer, friction, and lubrication process relevant to internal combustion engine design , performance , efficiecy , emissions ,and fuels requirements.

The thermal efficiency is governed chiefly by the range of temperature through which the Working fluid ,
be it gas or steam, passes on its way through the engine.This range of temperature is greater in internal combustion engines than in steam engines , hence the former are inherently capable of higher thermal
efficiencies, that is to say, thry are capable of converting into work a higher percentage of the total heat
of the fuel with which they are supplied than the latter .

Even so, the physical limitations are such that the thermal efficiency of a good Petrol engine is not more
than about 28% . The remaining heat supplied , which is not converted into work , is lost in the Exhaust
gases and cooling water, and in radiation.