IC ENGINE IC ENGINE IC ENGINE IC ENGINE IC ENGINE IC ENGINE IC ENGINE

I C ENGINE

1. ME-420 Internal Combustion Engines
Introduction, Applications
&Classifications

2. Content
nIntroduction
nApplication of IC engines
nParts of IC Engines
nClassification of IC Engines
nWorking of IC Engines
nDifference between Two stroke and Four Stroke
nDifference between SI and CI Engines

3. Introduction
Internal Combustion Engines
Heat Engines
External Combustion Engines
Definition of Heat Engines:-
It is mechanical device , which converts heat
energy into mechanical energy
Example:-Gas turbine power plants ,
Steam power Plants,
Internal Combustion Engines(automobiles)

4. External combustion Engines
nCombustion takes
place away from
work producing
place
nSteam power plants

5. Internal Combustion Engines
Combustion takes Place inside the Cylinder
(i.e., with in the work producing place)
Example:-All Type of automobile engines

6. Basic Principle of IC Engines
Combustion Is Key
To understand the basic idea behind how a
reciprocating internal combustion engine
works, it is helpful to have a good mental
image of how "internal combustion" works.
One good example is an old Revolutionary
War cannon. You have probably seen
these in movies, where the soldiers load
the cannon with gun powder and a cannon
ball and light it. That is internal
combustion,

7. Application of Internal combustion Engines
nRoad Vehicles
nAir Craft
nLocomotives
nPumping sets
nCinemas
nHospital
nSeveral Industrial application

8. Automobile
engineeringis the
activity of
designing and
constructing
automobiles

9. Back to Content

10. 1876 –Otto’s first prototype
1st practical ICE
Power: 2 hp; Weight: 1250 pounds
Comp. ratio = 4 (knock limited), 14%
efficiency (theory 38%)
Today CR = 9 (still knock limited),
30% efficiency (theory 55%)
1881 –Two stroke engine
1892 –Diesel’s first prototype
1921 -Antiknock effect of
tetraethyl lead –General Motors
1957 –Wankel’s first prototype
1975 -Catalytic converters,
unleaded fuel
1980s -Microcomputer control of
engines

11. Parts of an IC Engines (Petrol Engines)
Cylinder
Cylinder head
Piston and piston rings
Connecting Rod
Crank and Crankshaft
Inlet Valve
Exhaust Valve
Inlet manifold
Exhaust manifold
Cam and cam follower
push Rod and Rocker Arm
Crank Case
Flywheel
Carburetor
Spark plug

12. Parts of Diesel Engines

13. Basic Engine Nomenclature
Bore : Inside diameter of the cylinder
Top Dead Center : The extreme position of the piston at the top of the
cylinder(TDC)
Bottom Dead Center : The extreme position of the piston at the bottom of the
cylinder (BDC)
Stroke : The max distance traveled by the piston from TDC to BDC or vice versa
Clearance Volume : The volume contained in the cylinder above the top of the
piston When the piston at the TDC.
Piston Displacement or Swept Volume : The volume swept through by the piston
in moving from TDC to BDC.
Compression ratio : The ratio of the volume when the piston is at BDC to the
volume when the piston is at TDC
Back to Content

14. Classification of an IC Engines
nBased on Working Cycle
nBased on type of fuels used
nBased on Number of strokes
nBased on Cooling system
nBased on number of cylinders used
nBased on Cylinder arrangement
nBased on method of ignition
nBased on their application
nBased on method of Governing

15. Based on working Cycle
nOtto Cycle
nEx :-Petrol Engines
nDiesel Cycle
nEx : -Diesel Engines
nDuel Cycle
nEx :-special purpose
engines

16. Based on types of fuel used
nPetrol Engines
nDiesel Engines
nGaseous fuels Engines
Based on number of strokes
nTwo Stroke Engines
nPower is getting in one revolution of the crank i.e., in two stroke
nFour Stroke Engines
nPower is getting in two revolution of the crank i.e., in four stroke
nBased on Cooling System
nAir cooling
nWater cooling

17. Back
The Two-stroke Cycle

18. Based on number of cylinder
nSingle cylider Engines
nMulticylinder Engines
Based on Cylinder arrangements
nInline Engines
nV –Type Engines
nRadial Engines
nOpposed piston Engines
nOpposed cylinder Engines
nDelta Type Engines
Based on method of ignition
nSpark Ignition Engines(SI Engines)
nCompression ignition(CIEngines)

19. Based on Cooling System
Air Cooling Engines
Water Cooling Engines

20. Based on Cylinder arrangement
Inline Engines V Type Engines

21. Radial Engines Opposed piston Engines Opposed cylinder Engines
Delta type

22. Based on Method of ignition
Spark ignition Engines
Compression Ignition Engines
Spark ignition

23. Based on Application
nStationary Engines
nMarine Engines
nPortable Engines
nAutomobile Engines
nAero Engines
Based on method of Governing
nHit & miss governed Engines
nQuality governed Engines
nQuantity governed Engines

24. Ignition system in diesel engines

25. Working of IC Engines
nWorking of Two Stroke Engines
Petrol Engines
Diesel Engines
nWorking of Four Stroke Engines
Petrol Engines
Diesel Engines

26. Working of Two stroke Diesel Engines
nBased on Diesel Cycle
nFuel diesel
nPower is produced in every cycle

27. Working of two stroke diesel engines
Power is produced in one
revolution of the crank
shaft and suction,
compression, expansion
and exhaust stroke is
completed in two stroke
only.

28. Working of Two stoke petrol Engines

29. Working of Two stroke Petrol Engines
Back

30. Working of Four stroke Petrol Engines
Power is produced in four stroke
i.e.,two revolution of the crank
shaft
It work on Otto cycleand it completes
in four stroke of the piston
The cycle consisting of following
process
Suction stroke
Compression stroke
Expansion stroke or power stroke
Exhaust stroke
It requires carburetor and spark plug
Figure 1

31. Working of Four stroke Petrol Engines

32. Working of Four stroke diesel engines
Power is produced in four stroke
i.e.,two revolution of the crank
shaft
It work on Diesel Cycleand it
completes in four stroke of the
piston
The cycle consisting of following
process
Suction stroke
Compression stroke
Expansion stroke or power stroke
Exhaust stroke
It consists of fuel injection and
pumping arrangement

33. Working of Four stroke Diesel Engines

34. Difference between Two stroke and Four
Stroke Engines
Aspects Four StrokeTwo Stroke
Completion of Cycle The cycle is completed in 4S of
the piston/ one power stroke in 2
revolution of the crank
The cycle is completed in 2S of
the piston/ one power stroke in 1
revolution of the crank
Flywheel required
(heavior or lighter)
Turning moment is not uniform
and hence heavier flywheel is
need
Turning moment is uniform and
hence lighter flywheel is need
Power Produced for some size of
engine
Is small or for the same power
the engine is heavy and bulky
Is more (2 Times ) or for the
same power the engine is light
and compact
Cooling and lubricants
requirements
Lesser cooling &lubricantMore cooling and lubrication is
required
Valve and valve mechanism It contains valve and valve
mechanism
No valves
Initial cost Cost is high Initial cost is less

35. Difference between Two stroke and Four Stroke
Engines
Aspects Four StrokeTwo Stroke
Volumetric efficiency more less
Thermal and part load
efficiencies
Higher and at part load efficiency
is more
Less and at part load efficiency
is less
application Cars, buses, truces, tractor ,
industrial application and etc..
Lawn movers, scooters, motor
cycles, and etc..

36. Difference between Petrol Engines and Diesel
Engines
PETROL ENGINES DIESEL ENGINES
It works on Otto Cycle It works on Diesel cycle
It draws a mixture of petrol and air during suction
stroke
It draws only air during suction stroke
Carburetor/MPFI is employed to mix air and petrol
during suction stroke.
Injector is employed to inject the fuel at the end of
compression stroke
Pressure at the end of compression is about 10 to 15
bar
Pressure at the end of compression is about 50 bar to
75 bar
The charge is ignited with the help of spark plugSelf ignited ( end of compression stroke temperature
is about 600°C)
It has a compression ratio approximately from 6 to 12It has a compression ratio approximately from14 to22
The maintenance cost is less high
The thermal efficiency is uptoabout 30% Thermal efficiency is upto 40%

37. Power and Mechanical efficiencies
Indicated power (IP) = (nPmi LANK10)/(6) KW
Brake power(BP) = (2iiNT )/(60*1000) KW
Frictional power(FP) = IP-BP
Mechanical efficiencyηmech= BP/IP
Thermal efficiencyηther= IP/heat input or = BP/ heat input
Volumetric efficiencyηVole = actual volume of the charge drawn/swept volume
Fuel –Air rartio = mass fuel to mass of air

38. ***A course in Internal combustion engines
By V.M. Domkundwar
***A course in Internal combustion engines
By Mathur and sharma
*** Internal combustion engines
By V. Ganesan
*** auto.howstuffworks.com/engine.html/
*** Google search “ animation of working of
internal combustion engines “
Reference to this topic