The document discusses the components and functions of a crankshaft. It lists the group members and defines a crankshaft as a shaft that transmits power from the engine and converts the reciprocating motion of the piston into rotational motion. It describes the main parts of the crankshaft including the throws, journals, webs, counterweights, big end bearings and main bearings. It explains that counterweights are needed to balance the crankshaft and prevent vibrations from damaging the engine.

2. Group Members
 Muhammad Talha Farooq (14-ME-123)
 Muhammad Talha Rasheed (14-ME-124)
 Muhammad Talha Sherwani (14-ME-125)
 Muhammad Tariq Nadeem (14-ME-127)

3. What is Crankshaft?
 It is a shaft which transmits the power developed by the
engine to the various parts of the vehicle.
 It is a link between the input and output of the vehicle.
Without crankshaft your vehicle won't even move an inch
though your engine will be running.

4. Types of Crankshaft
 Same plane
 Cross plane

5. Types of Crankshaft
 Single Throw Crankshaft
 Double Throw Crankshaft
 Four Throw Crankshaft
 Six Throw Crankshaft

6. Function of Crankshaft
 Changes reciprocating motion of piston into rotating motion
to drive propeller.
 Constructed of chrome-nikel-molydenum-steel.
 The propeller is mounted the front of crankshaft using a
spline, taper or flange.
 Crankshaft rotates within the crankcase and is supported by
main bearing journals.

7. Parts of Crankshaft

8. Crank Shaft

9. Web
The portion of a crank between
the crankpin and the shaft or between
adjacent crankpins —called also crank arm,
crank throw

10. Counter Weight
 Crankshaft counterweights are designed to offset (or balance)
the inertia effect of a relatively heavy piston and connecting
rod moving in both a rotational and reciprocating (up-and-
down) fashion. The weight of the piston and connecting rod
combination affects the size and placement of the
counterweight.
 If this is not done, the engine will experience vibrations that
will eventually tear up the main bearings and cause damage.
 Crankshaft counter weights are needed to statically and
dynamically balance the crankshaft.
Without them, the vibrations caused will destroy it.

11. Crank journals
 In a reciprocating engine, the crankpins, also known
as crank journals are the journals of the big
end bearings, at the ends of the connecting rods opposite
to the piston.
 If the engine has a crankshaft, then the crank pins are the
journals of the off-centre bearings of the crankshaft. In a
beam engine, the single crank pin is mounted on the
flywheel
 In a steam locomotive, the crank pins are often mounted
directly on the driving wheels.

12. Big End Bearings

13. Main bearings
 In a piston engine, the main bearings are the bearing on
which the crankshaft rotates, usually plain or journal
bearings. The bearings hold the crankshaft in place and
prevent the forces created by the piston and transmitted
to the crankshaft by the connecting rods from dislodging
the crankshaft, instead forcing the crank to convert the
reciprocating movement into rotation.

14. Main Bearings

15. Conclusion
Crankshaft serves as important part of an engine in
avoiding vibrational motion and it allows smooth
transmission of power from engine to various parts.
Conversion of reciprocatory motion to rotational motion
was made possible using crankshaft.

16. Reference Links
 https://www.quora.com/What-is-a-crankshaft
 http://www.onallcylinders.com/2015/01/15/cross-plane-
vs-flat-plane-crankshafts/