Components of an internal combustion (I.C.) engine


  • Cylinder block:-

  1. The basic framework of the engine is formed by the cylinder block.
  2. It houses the engine cylinders, which serves as bearings and guides for the pistons reciprocating in them.
  3. Cylinder block also carries lubrication oil to various components through drilled passages.
  4. Materials: Alloy cast iron, Aluminium alloy.
  • Cylinder head:-
  1. It is attached to the top of the cylinder block by means of studs fixed to the block.
  2. The cylinder head forms a combustion chamber above each cylinder.
  3. It also contains spark plug or injector holes and cooling water jackets.
  4. Materials: Aluminium alloy, gray iron or cast iron.
  • Head gasket:-
  1. The cylinder head gasket is used to obtain a water and gas-tight joint.
  2. It has a heat proof material to combat high temperature and pressure.
  3. Materials: copper fillings or asbestos is filled and pressed in between two thin copper or steel sheet.
  • Crankcase:-
  1. The part of the cylinder block which houses the revolving parts, the crankshaft and the camshaft is termed as crankcase.
  2. Materials:Cast iron, aluminium.
  • Engine sump:-
  1. It is used to store lubricating oil and prevention of oil swirl, when the vehicle is in motion.
  2. It also collects grit and dirt at the lowest point.
  3. Materials: Pressed sheet steel.
  • Piston Pins:-
  1. The piston and gudgeon pin connect the piston with the small end of the connecting rod.
  2. Materials: Nickel-chromium alloy steel.

  • Connecting rod:-

  1. The connecting rod is act as a link between the piston and the crankshaft.
  2. It converts the reciprocating motion of the piston into a rotary motion.
  3. Materials: High grade alloy steel and drop-forged steel.
  • Engine valves:-
  1. Every cylinder of a four stroke engine has two valves: the intake and the exhaust.
  2. Materials: Inlet valves- Nickel chromium alloy steel.
  3. Materials: Exhaust valve- Silicon chromium alloy steel.
  • Camshaft:-
  1. The camshaft changes the rotary motion of the crankshaft into reciprocating motion at the valve.
  2. It also runs other accessories like lubricating gear pump, distributor, mechanical fuel pump and compressor.
  3. Material: High quality of gray iron, alloy steel.

  • Piston:-
  1. The piston is cylindrical is in shape and forms the movable portion of the combustion chamber.
  2. The gas pressure acts on the head of the piston which is also called crown.
  3. The force due to this pressure is transmitted to the connecting rod via the piston.
  4. The connecting rod help to change the reciprocating motion of piston into a revolving motion at the crank shaft.

  • Piston Ring:-
  1. The ring is generally casted individually and machined carefully so that it is able to exert uniform pressure against the cylinder walls.
  2. To form a seal for the high pressure gases from the combustion chamber against leak into the crank case.
  3. To provide easy passage for heat flow from the piston crown to the cylinder walls.
  4. To maintain sufficient lubricating oil on cylinder walls throughout the entire length of thr piston travel.

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