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Nomenclature of IC Engines

The document defines key terminology used in internal combustion engines, including: - Cylinder bore, piston area, and stroke, which describe the physical dimensions of the engine. - Stroke to bore ratio, which classifies engines as under square, square, or over square. - Top dead centre and bottom dead centre, which define the limits of the piston's movement. - Displacement or swept volume, which is the volume displaced by the piston from one dead centre to the other. - Compression ratio, which is the ratio of total cylinder volume to clearance volume. It then briefly discusses two-stroke and four-stroke gasoline and diesel engines and some of their common applications.

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Surjit Kumar Gandhi
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666 views10 pages

Nomenclature of IC Engines

The document defines key terminology used in internal combustion engines, including: - Cylinder bore, piston area, and stroke, which describe the physical dimensions of the engine. - Stroke to bore ratio, which classifies engines as under square, square, or over square. - Top dead centre and bottom dead centre, which define the limits of the piston's movement. - Displacement or swept volume, which is the volume displaced by the piston from one dead centre to the other. - Compression ratio, which is the ratio of total cylinder volume to clearance volume. It then briefly discusses two-stroke and four-stroke gasoline and diesel engines and some of their common applications.

Uploaded by

Surjit Kumar Gandhi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPTX, PDF, TXT or read online on Scribd
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Terminology

of
IC Engines

Dr. S. K. Gandhi
PCTEIET Ludhiana
•Cylinder bore (d) :-
The nominal inner diameter of the working cylinder is
called bore and designated by the letter d and is usually
expressed in millimeter(mm).

•Piston area (A) :-


The area of a circle of diameter equal to the cylinder
bore is called the piston area and designated by the letter A
and usually expressed in square centimeter.

• Stroke (L)
The nominal distance through which a working
piston moves between two successive reversals of its
directions of motion is called the stroke and designated
by the letter L and usually expressed in millimeter.
• Stroke to Bore ratio :-
L/d ratio is an important parameter in classifying
the size of the engine.
If d<L, it is called under square engine.
If d=L ,it is called square engine.
If d>L, it is called over square engine.

•Dead Centre:-
The position of the working piston and moving parts
which are mechanically connected to it, at the moment
when the direction of the piston motion is reversed at
either and of the stroke is called the dead centre. There
are two types of dead centre

A. Top dead centre ( T.D.C )


B. Bottom dead centre (B.D.C)
A. Top dead centre:-
It is the dead centre when piston is farthest
from the crankshaft . It is designated as TDC for
vertical engines and Inner Dead Centre (I D C) for
horizontal engines .

B. Bottom dead centre:-


It is the dead centre when the piston is
nearest to the crankshaft. It is designated as BDC for
vertical engines and Outer Dead Centre (O D C) for
horizontal engines.

Displacement or swept volume :-


The nominal volume swept by the working piston
when Travelling from one dead centre to the other is
called the displacement volume .
It is expressed in terms of cubic centimeter (cc) and given
by

Vs = A x L = (3.14*d*d*l)/4
Cubic capacity or engine capacity:-
The displacement volume of a cylinder multiplied by Number
of cylinder in an engine will give the cubic capacity. If there are
K cylinders in an engine , then
cubic capacity = Vs x K

Clearance volume (Vc):-


The nominal volume of the combustion chamber above the
piston when it is at the top dead centre is the clearance volume. It
is expressed in cubic centimeter(cc).

Compression ratio (r) :-


It is the ratio of total cylinder volume when the piston is at
the bottom dead centre, VT , to the clearance volume , VC. It is
designated by the letter r.

r = VT / Vc = (Vc + Vs)/ Vc = 1+(Vs / Vc)


Basic Components of IC Engine
Piston
Applications of IC Engines
Applications of IC Engines: Transport on Land/ Sea/ Air,
Industries, Electric Generators.

• Two Stroke Gasoline Engines: Used where simplicity and low cost is the main
consideration. Have high specific fuel consumption due to loss of fuel air charge in

the process of scavenging.


• Two Stroke Diesel Engines: Very High power diesel engines used for ship
propulsion.

• Four Stroke Gasoline Engines: Earlier Four Stroke Gasoline Engines were used in

buses, cars , aircrafts.


• Four Stroke Diesel Engines: Agriculture purpose, Jeeps, Buses, Trucks, Earth
moving machines.

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