The main components of an internal combustion (IC) engine include the cylinder block, cylinder head, piston, cylinder, piston rings, connecting rod, crankshaft, camshaft, valves, fuel injector or spark plug, crankcase, and flywheel. The cylinder block forms the main structure and houses the cylinders, while the cylinder head covers the top of the cylinders and includes components like the valves and fuel injector. The piston is fitted inside the cylinder and transfers the force from combustion to the connecting rod. The connecting rod then converts the reciprocating motion of the piston to rotational motion through the crankshaft.

1. Components of IC Engine

2. ● Cylinder block
● Cylinder Head
● Piston
● Cylinder
● Piston Rings
● Gudgeon Pin
● Connecting Rod
● Crankshaft
● Cam Shaft
● Cams
● Inlet & Exhaust valve
● Fuel Injector
● Spark Plug
● Crankcase
● Flywheel
Components of IC Engine

3. The cylinder block is the main supporting structure for the various components. The
cylinder of multi cylinder engine are cast in single unit called as Cylinder Block
➔ Material : Cast Iron, Aluminum alloy
◆ CI for diesel engines, that
produce stronger explosion.
◆ Al for gasoline engine that
produces soft explosion.
Cylinder Block

4. Cylinder Head
The top end of the cylinder is covered by cylinder head over which inlet and
exhaust valve, spark plug or injectors are mounted

5. Piston
● It is cylindrical component fitted into the cylinder forming the moving boundary
of combustion system.
● Transmit the force exerted by the burning of charge to the connecting rod
● It fits perfectly into the cylinder providing a gas-tight space with the piston ring
and lubricant.
➔ Material : aluminium alloy
◆ Light Weight
◆ Thermal Conductivity
◆ Good tensile strength

8. Cylinder
● It is the main part of the engine in which the piston reciprocate to and fro.
● It also acts in transferring the heat from:
○ combustion chamber to water jacket in liquid cooled engine.
○ Combustion chamber to fins in air cooled engine.
➔ Material : Cast Iron
◆ Good wear Resistance
◆ Good Damping behaviour
◆ High Thermal conductivity
◆ inexpensive

11. Piston Rings
● Piston rings, fitted into the slots around the piston, provides tight seal between
the piston and cylinder wall thus preventing the leakage of combustion gases.
● There are two types of rings:
○ Compression ring is upper ring of the piston which provides air tight seal to prevent
leakage of the burnt gases into the lower portion.
○ Oil ring is lower ring which provides effective seal to prevent leakage of the oil
into the engine cylinder.
➔ Material : Cast Iron, steel
alloys(coated or heat treated)
◆ High thermal conductivity
◆ Wear resistance

14. Connecting Rod
● It converts reciprocating motion of the piston into circular motion of the
crankshaft, in the working stroke.
● The smaller end of the connecting rod is connected with the piston by
gudgeon pin and bigger end of the connecting rod is connected with the
crank with crank pin.
➔ Material : Steel alloys(drop
forged), Titanium, Aluminum
◆ Lightweight, flexible (Al)
◆ High performance(Ti)

17. Gudgeon Pin
It forms the link between the small end of connecting rod and piston

18. Crankshaft
● It converts the reciprocating motion of the piston into the useful rotary motion
of output shaft with the help of connecting rod.
● In the crankshaft of single cylinder engine there are a pair of crank arms and a
balance weights. The balance weights are provided for static and dynamic
balancing of the rotatory system.
● The crankshaft is enclose in the crankcase
➔ Material: Medium carbon
steel alloy(0.25-0.45%C) -
Foging
◆ High fatigue strength
◆ Hardness

20. Cam Shaft
● The cam shaft and its associate parts control the opening and closing of two
valves. The associate parts are pushrod, rocker arms,valve spring and tappets.
● The shaft also provide the drive to the ignition system.
● The camshaft is driven by the crankshaft through timing chain or timing gears.
➔ Material : chilled cast iron(1% Cr),
Billet Steel.
◆ high volume production,
have good wear resistance.
◆ high quality camshaft or low
volume production

22. Cams
These are made as integral parts of the camshaft and are designed in such a way to
open the valves at the correct timings and to keep them open for necessary duration
Cams

23. Inlet and exhaust valves
● Valves are commonly mushroom shape poppet type
● They are provided on the cylinder head for regulating the charge coming into
the cylinder(inlet valve) and for discharging the products of combustion
(exhaust valve) from the cylinder.
➔ Material: Stainless steel,
Titanium, Inconel,
◆ high
temperature,oxidation
,corrosion resistant

27. Spark Plug
● It is a component to initiate the combustion process in spark ignition(SI) engines
and is usually located on the cylinder head.

28. Fuel Injector
● It is a component to initiate the combustion process in compression ignition(CI)
engines and is usually located on the cylinder head.

30. CrankCase
● It is the bottom part of the Engine block
● It hose the crankshaft of the IC Engine and also serve as the sump for the
lubricating oil.

31. Flywheel
● It is big wheel mounted on the crankshaft, whose function is to maintain
its speed constant. It is done by storing excess energy during the power
stroke, which is returned during other stroke.
➔ Material : Cast iron,
Steel, (Dense Material)

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