This document provides an overview of internal combustion engines. It describes the basic components of an internal combustion engine including the cylinder, piston, connecting rod, crankshaft, and spark plug. It explains that internal combustion engines convert the chemical energy in a fuel into heat energy during combustion, and then into mechanical energy. The document further categorizes internal combustion engines and provides details on the workings of 4-stroke diesel and 2-stroke diesel engines in terms of their intake, compression, combustion, and exhaust strokes.

1. INTERNAL COMBUSTION I.C.INTERNAL COMBUSTION I.C.
ENGINE-A.J.More AISSMSIOITENGINE-A.J.More AISSMSIOIT
INTRODUCTIONINTRODUCTION ::
A HEAT ENGINE IS A DEVICEA HEAT ENGINE IS A DEVICE
IN WHICH CHEMICAL ENERGY OF AIN WHICH CHEMICAL ENERGY OF A
FUEL IS FIRST CONVERTED INTOFUEL IS FIRST CONVERTED INTO
HEAT ENERGY , SUBSEQUENTLY THISHEAT ENERGY , SUBSEQUENTLY THIS
HEAT ENERGY IS CONVERTED INTOHEAT ENERGY IS CONVERTED INTO
MECHANICAL ENERGY.MECHANICAL ENERGY.

2. TYPES OF HEAT ENGINESTYPES OF HEAT ENGINES
1.1. EXTERNAL COMBUSTIONEXTERNAL COMBUSTION
ENGINESENGINES
2.2. INTERNAL COMBUSTIONINTERNAL COMBUSTION
ENGINESENGINES

4. ENGINE COMPONENTSENGINE COMPONENTS
1.1. CYLINDERCYLINDER : A CYLINDER IN AN I.C.: A CYLINDER IN AN I.C.
ENGINE HAVE TO WITHSTAND UPTO 70ENGINE HAVE TO WITHSTAND UPTO 70
BAR & TEMPERATURE UPTO 2500’CBAR & TEMPERATURE UPTO 2500’C
BECAUSE THE COMBUSTION OF FUEL ISBECAUSE THE COMBUSTION OF FUEL IS
CARRIED OUT WITHIN THE CYLINDER.CARRIED OUT WITHIN THE CYLINDER.
THEREFORE , CYLINDERS MUST BETHEREFORE , CYLINDERS MUST BE
COOLED.COOLED.
MATERIALS USED ARE CAST IRONMATERIALS USED ARE CAST IRON
AND ALLOY STEEL .AND ALLOY STEEL .

5. 2.2. CYLINDER HEADCYLINDER HEAD : TO SEAL TOP END OF: TO SEAL TOP END OF
THE CYLINDER .THE CYLINDER .
3.3. PISTON & PISTON RINGSPISTON & PISTON RINGS : TO TRANSMIT: TO TRANSMIT
THE GAS FORCE TO CONNECTING ROD ,THE GAS FORCE TO CONNECTING ROD ,
HENCE TO THE CRANK. PISTON RINGS AREHENCE TO THE CRANK. PISTON RINGS ARE
PROVIDED TO PREVENT THE LEAKAGE OFPROVIDED TO PREVENT THE LEAKAGE OF
THE GAS TO CRANK CASE.THE GAS TO CRANK CASE.
4.4. PISTON PINPISTON PIN : IT IS MADE OF HARDENED: IT IS MADE OF HARDENED
STEEL IN SHAPE OF SPINDLE. IT CONNECTSSTEEL IN SHAPE OF SPINDLE. IT CONNECTS
THE PISTON TO SMALL END OFTHE PISTON TO SMALL END OF
CONNECTING ROD .CONNECTING ROD .

6. 5.5. CONNECTING RODCONNECTING ROD : ONE END IS: ONE END IS
CONNECTED TO PISTON THROUGHCONNECTED TO PISTON THROUGH
PISTON PIN AND OTHER END TO CRANK.PISTON PIN AND OTHER END TO CRANK.
IT CONVERTS RECIPROCATING MOTIONIT CONVERTS RECIPROCATING MOTION
INTO ROTARY MOTION OF CRANK SHAFT.INTO ROTARY MOTION OF CRANK SHAFT.
6.6. CRANK & CRANKSHAFTCRANK & CRANKSHAFT : CRANK IS: CRANK IS
INTEGRAL PART OF CRANKSHAFT.INTEGRAL PART OF CRANKSHAFT.
CRANKSHAFT IS SUPPORTED IN MAINCRANKSHAFT IS SUPPORTED IN MAIN
BEARINGS AND CARRIES BALANCINGBEARINGS AND CARRIES BALANCING
WEIGHTS. THEY ARE STEEL FORGED ANDWEIGHTS. THEY ARE STEEL FORGED AND
MACHINED TO SMOOTH FINISH.MACHINED TO SMOOTH FINISH.

7. 7.7. FLYWHEELFLYWHEEL : HEAVY ROTATING MASS IS: HEAVY ROTATING MASS IS
ATTACHED TO CRANKSHAFT OUTSIDE THEATTACHED TO CRANKSHAFT OUTSIDE THE
CRANKCASE. IT’S FUNCTION IS TO SMOOTHCRANKCASE. IT’S FUNCTION IS TO SMOOTH
OUT CYCLIC FLUCTUATION OF TORQUEOUT CYCLIC FLUCTUATION OF TORQUE
DEVELOPED BY THE RECIPROCATINGDEVELOPED BY THE RECIPROCATING
ENGINE.ENGINE.
8.8. SPARK PLUGSPARK PLUG : TO PROVIDE A HIGH: TO PROVIDE A HIGH
INTENSITY SPARK FOR COMBUSTION OFINTENSITY SPARK FOR COMBUSTION OF
FUEL AND AIR IN THE CYLINDER IN SPARKFUEL AND AIR IN THE CYLINDER IN SPARK
IGNITION ENGINES.IGNITION ENGINES.

8. CLASSIFICATION OF INTERNALCLASSIFICATION OF INTERNAL
COMBUTION ENGINECOMBUTION ENGINE
(1)NUMBER OF STROKES PER CYCLE.(1)NUMBER OF STROKES PER CYCLE.
(2)THERMODYNAMIC CYCLE.(2)THERMODYNAMIC CYCLE.
(3)NUMBER OF CYLINDERS.(3)NUMBER OF CYLINDERS.
(4)FUEL USED.(4)FUEL USED.

9. (5) LUBRICATION SYSTEM.(5) LUBRICATION SYSTEM.
(6) COOLING SYSTEM.(6) COOLING SYSTEM.
(7) FUEL SUPPLY SYSTEM.(7) FUEL SUPPLY SYSTEM.
(8) IGNITION SYSTEM.(8) IGNITION SYSTEM.
(9) ARRANGEMENT OF CYLINDER.(9) ARRANGEMENT OF CYLINDER.

10. WORKING OF 4 STROKEWORKING OF 4 STROKE
DIESEL ENGINEDIESEL ENGINE
(A)(A) SUCTION STROKESUCTION STROKE
(B)(B) COMPRESSION STROKECOMPRESSION STROKE
(C)(C)EXPANSION STROKEEXPANSION STROKE
(D)(D)EXHAUST STROKEEXHAUST STROKE

12. SUCTION STROKESUCTION STROKE
 INLET VALVE OPENS & EXHAUSTINLET VALVE OPENS & EXHAUST
VALVE REMAINS CLOSED.VALVE REMAINS CLOSED.
 ONLY AIR IS INDUCTED DURINGONLY AIR IS INDUCTED DURING
SUCTION STROKE.SUCTION STROKE.
 PISTON MOVES FROM TDC TO BDC.PISTON MOVES FROM TDC TO BDC.

13. SUCTION STROKESUCTION STROKE
 INLET VALVE OPENS & EXHAUSTINLET VALVE OPENS & EXHAUST
VALVE REMAINS CLOSED.VALVE REMAINS CLOSED.
 ONLY AIR IS INDUCTED DURINGONLY AIR IS INDUCTED DURING
SUCTION STROKE.SUCTION STROKE.
 PISTON MOVES FROM TDC TO BDC.PISTON MOVES FROM TDC TO BDC.

14. COMPRESSION STROKECOMPRESSION STROKE
 BOTH INLET VALVE AND EXHAUSTBOTH INLET VALVE AND EXHAUST
VALVE REMAIN CLOSED.VALVE REMAIN CLOSED.
 AIR SUCKED DURING SUCTIONAIR SUCKED DURING SUCTION
STROKE IS COMPERSSED UPTO ITSSTROKE IS COMPERSSED UPTO ITS
CLEARANCE VOLUME.CLEARANCE VOLUME.
 PISTON MOVES FROM BDC TO TDC.PISTON MOVES FROM BDC TO TDC.

15. EXPANSION STROKEEXPANSION STROKE
 DUE TO COMBUTION OF FUEL ,HEATDUE TO COMBUTION OF FUEL ,HEAT
IS ASSUMED TO BE ADDED ATIS ASSUMED TO BE ADDED AT
CONSTAT PRESSURE.CONSTAT PRESSURE.
 THE PRODUCTS OF COMBUSTIONTHE PRODUCTS OF COMBUSTION
EXPAND DURING PISTON MOVEMENTEXPAND DURING PISTON MOVEMENT
FROM TDC TO BDC.FROM TDC TO BDC.

16. EXHAUST STROKEEXHAUST STROKE
EXHAUST VALVE OPENS & INTAKEEXHAUST VALVE OPENS & INTAKE
VALVE REMAINS CLOSED.VALVE REMAINS CLOSED.
DIESEL ENGINE USES VERY HIGHDIESEL ENGINE USES VERY HIGH
COMPRESSION RATIO.COMPRESSION RATIO.
IT IS AUTO IGNITION.IT IS AUTO IGNITION.

20. WORKINGWORKING
THE WORKING OF A COMPRESSION IGNITIONTHE WORKING OF A COMPRESSION IGNITION
ENGINE IS BASED ON THE ENGINE DESIGNED BYENGINE IS BASED ON THE ENGINE DESIGNED BY
GERMAN ENGINEER, RADOLF DIESEL IN 1892GERMAN ENGINEER, RADOLF DIESEL IN 1892
THE WORKING IS SAME AS PETROL ENGINE ONLYTHE WORKING IS SAME AS PETROL ENGINE ONLY
THE AIR IS DRAWN DURING THE SUCTION STROKETHE AIR IS DRAWN DURING THE SUCTION STROKE
THE FUEL IS INJECTED INTO THE CYLINDERTHE FUEL IS INJECTED INTO THE CYLINDER
BEFORE THE END OF COMPRESSION STROKEBEFORE THE END OF COMPRESSION STROKE
UNDER VERY HIGH PRESSURESUNDER VERY HIGH PRESSURES
THE WORKING FUEL IS DIESEL AND IT OPERATESTHE WORKING FUEL IS DIESEL AND IT OPERATES
ON DIESEL CYCLE . THE COMPRESSION RATIO USEDON DIESEL CYCLE . THE COMPRESSION RATIO USED
FOR DIESEL ENGINES VARIES FROM 14 TO 20FOR DIESEL ENGINES VARIES FROM 14 TO 20

22. WORKING OF 2 STROKE DIESELWORKING OF 2 STROKE DIESEL
ENGINEENGINE

24.  CONSIDER PISTON AT TDC. WHEN PISTONCONSIDER PISTON AT TDC. WHEN PISTON
MOVES DOWN HOT GASES EXPANDMOVES DOWN HOT GASES EXPAND
DURING IT’S DOWNWARD MOTION, THEDURING IT’S DOWNWARD MOTION, THE
PISTON FIRSTLY UNCOVER THE EXHAUSTPISTON FIRSTLY UNCOVER THE EXHAUST
PORT & A LITTLE LATER IT UNCOVER THEPORT & A LITTLE LATER IT UNCOVER THE
TRANSFER PORT.TRANSFER PORT.
 THE AIR COMPRESS DURING THETHE AIR COMPRESS DURING THE
PRIVIOUS STROKE IN THE CRANK CASE ITPRIVIOUS STROKE IN THE CRANK CASE IT
TRANSFERRED INTO THE CYLINDER VIATRANSFERRED INTO THE CYLINDER VIA
TRANSFER PORT.THIS INCOMING AIRTRANSFER PORT.THIS INCOMING AIR
PUSHES OUT THE BURNT GASES WHILEPUSHES OUT THE BURNT GASES WHILE
PASSING OVER THE DEFLECTOR.PASSING OVER THE DEFLECTOR.

25.  PISTON MOVES FROM BDC TO TDC. ITPISTON MOVES FROM BDC TO TDC. IT
FIRST CLOSES TRANSFER PORT & AFIRST CLOSES TRANSFER PORT & A
LITTLE LATER EXHAUST PORT.LITTLE LATER EXHAUST PORT.
 THE AIR TRANSFERRED EARLIERTHE AIR TRANSFERRED EARLIER
INTO THE CYLINDER IS NOWINTO THE CYLINDER IS NOW
COMPRESSED WITH FURTHERCOMPRESSED WITH FURTHER
MOVEMENT OF PISTON UPWARDS.MOVEMENT OF PISTON UPWARDS.
SIMULTANEOUSLY, VACCUM ISSIMULTANEOUSLY, VACCUM IS
CREATED IN CRANK CASE DUE TOCREATED IN CRANK CASE DUE TO
WHICH FRESH AIR IS DRAWN INSIDEWHICH FRESH AIR IS DRAWN INSIDE
CRANK CASE THROUGH INLET PORT.CRANK CASE THROUGH INLET PORT.

26.  BEFORE THE END OF COMPRESSIONBEFORE THE END OF COMPRESSION
STROKE , THE FUEL IS INJECTED &STROKE , THE FUEL IS INJECTED &
ATOMISED FUEL BURNS DUE TO HIGHATOMISED FUEL BURNS DUE TO HIGH
TEMP OF AIR CALLED AUTOIGNITION.TEMP OF AIR CALLED AUTOIGNITION.
 THE RESULTED HOT GASES WILLTHE RESULTED HOT GASES WILL
AGAIN EXPAND, THUS COMPLETING AAGAIN EXPAND, THUS COMPLETING A
CYCLE.CYCLE.

28. 4 STROKE CYCLE4 STROKE CYCLE
ENGINEENGINE
1)1) CYCLE ISCYCLE IS
COMPLETED INCOMPLETED IN
TWO REVOLUTIONTWO REVOLUTION
OF THEOF THE
CRANKSHAFT.CRANKSHAFT.
2)2) THERMALTHERMAL
EFFICIENCY ISEFFICIENCY IS
HIGH.HIGH.
3)3) HEAVIERHEAVIER
FLYWHEEL.FLYWHEEL.
4)4) POEWR PRODUCEPOEWR PRODUCE
IS LESS.IS LESS.
2 STROKE CYCLE2 STROKE CYCLE
ENGINEENGINE
1)1) CYCLE ISCYCLE IS
COMPLETED INCOMPLETED IN
ONE REVOLUTIONONE REVOLUTION
OF THEOF THE
CRANKSHAFT.CRANKSHAFT.
2)2) THERMALTHERMAL
EFFICIENCY ISEFFICIENCY IS
LOW.LOW.
3)3) LIGHTERLIGHTER
FLYWHEEL.FLYWHEEL.
4)4) POWER PRODUCEPOWER PRODUCE
IS HIGH.IS HIGH.

29. ANY QUESTIONS ?????????ANY QUESTIONS ?????????