The document discusses the crankshaft component of an internal combustion engine. It begins with an introduction to crankshafts and their purpose of converting the reciprocating motion of pistons into rotational motion. It then describes the main parts of a crankshaft, including webs, counterweights, crank journals, and flywheels. Different types of crankshafts are also shown. The document concludes with a discussion of designing a crankshaft, including considerations for material selection and sizing based on engine specifications.

1. 1
University of Baghdad
College of Engineering
Department of Mechanical Engineering
Name of experiment
Crank shaft I.C ENGINE
:‫االسم‬
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‫حمزة‬ ‫مرزة‬ ‫حاتم‬ ‫عدي‬
:‫شعبة‬
-
‫أ‬
:‫المرحلة‬
-
‫الرابعة‬

2. 2
Experiment name
IC (INTERNAL COMBUSTION) ENGINE
INTRODUCTION:-
An internal combustion engine (ICE) is a heat engine where the combustion of a
fuel occurs with an oxidizer (usually air) in a combustion chamber that is an
integral part of the working fluid flow circuit. In an internal combustion engine the
expansion of the high-temperature and high-pressure gases produced by
combustion apply direct force to some component of the engine. The force is
applied typically to pistons, turbine blades, or a nozzle. This force moves the
component over a distance, transforming chemical energy into useful mechanical
energy. The first commercially successful internal combustion engine was
created by Etienne Lenoir around 1859 and the first modern internal combustion
engine was created in 1864 by Siegfried Marcus
Diagram of a cylinder as found in 4-stroke gasoline engines:-
C – crankshaft.
E – Exhaust camshaft.
I – Inlet camshaft.
P – piston.
R – Connecting rod.
S – Spark plug.
V – Valves. red: exhaust, blue: intake.
W – Cooling water jacket.

3. 3
Applications:-
Reciprocating engine as found inside a car Reciprocating piston engines are by far
the most common power source for land and water vehicles, including
automobiles, motorcycles,ships and to a lesser extent, locomotives (some are
electrical but most use Diesel engines. Wankel engines are used in some
automobiles and motorcycles. Where very high power-to-weight ratios are
required, internal combustion engines appear in the form of combustion turbines.
Powered aircraft typically uses an ICE which may be a reciprocating engine.
Airplanes can instead use jet engines and helicopters can instead employ
turboshafts; both of which are types of turbines. In addition to providing
propulsion, airliners employ a separate ICE as an auxiliary power unit.
Big Diesel generator used for backup power Combined cycle power
plant
ICEs drive some of the large electric generators that power electrical grids. They
are found in the form of combustion turbines in combined cycle power plants with
a typical electrical output in the range of 100 MW to 1 GW. The high temperature
exhaust is used to boil and superheat water to run a steam turbine. Thus, the
efficiency is higher because more energy is extracted from the fuel than what could
be extracted by the combustion turbine alone. In combined cycle power
plants efficiencies in the range of 50 % to 60 % are typical. In a smaller scale
Diesel generators are used for backup power and for providing electrical power to
areas not connected to an electric grid. Small engines (usually 2‐stroke gasoline
engines) are a common power source for lawnmowers, string trimmers, chain
saws, leaf blowers, pressure

4. 4
Classification:-
There are several possible ways to classify internal combustion engines.
Reciprocating:

By number of strokes
Two-stroke engine
Four-stroke engine (Otto cycle)
Six-stroke engine

By type of ignition
Compression-ignition engine
Spark-ignition engine (commonly found as gasoline engines)

By mechanical/thermodynamical cycle (these 2 cycles do not encompass all
reciprocating engines, and are infrequently used):
Atkinson cycle
Miller cycle
Continuous combustion:
Gas turbine
Jet engine
Rocket engine
Ramjet

The following jet engine types are also gas turbines types:
Turbojet Turbofan Turboprop

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Crank shaft
1.Introduction:-
The crankshaft is located in the engine of a vehicle and converts the force
created by the engine's pistons moving up and down into a force that
moves the wheels in a circular motion so the car can go forward. Located
inside the car's engine, it is connected to all the pistons in the engine and
to the flywheel. To understand this shaft, it is important to understand how
the pistons and the flywheel work.
Fig.1 Crankshaft and piston

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2.Main parts of crankshaft:-
2.1 Web :-
The portion of a crank between the crankpin and the shaft or between
adjacent crankpins called also crank arm, crank throw.
2.2 Counter Weight :-
Crankshaft counter weights are needed to statically and dynamically
balance the crankshaft. Without them, the vibrations caused will destroy it.
If this is not done, the engine will experience vibrations that will eventually
tear up the main bearings and cause damage.
2.3 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.

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2.4 CRANK JOURNAL PIN
The oil passes through the ammonium crank with holes and passes the oil
inside the tube into the column to the spike and the connecting column.
The oil reaches the crankshaft through a pump located inside the oil filter
Fig.3 Crank journal pin
2.5 Flywheel :-
Flywheel is bolted and fixed connected to crankshaft. And we cannot differentiate
on macroscopic time scale the power stroke or suction stroke or in which stroke
the flywheel is storing the excessive energy. Flywheel just stores the excessive
energy in form of kinetic energy and immediately after power stroke crankshaft
uses it in other power deficient strokes. Flywheel rotates with same speed as
crankshaft
Fig.4 Crank flywheel

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3. Types of crankshafts:-
3.1 Single Throw Crankshaft 3.2 Double Throw Crankshaft
Fig.5 Single throw crankshaft Fig.6 Double throw crankshaft
3.3 Four Throw Crankshaft 3.4 Six Throw Crankshaft
Fig.7 Four throw crankshaft Fig.8 Six throw crankshaft

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4. Material Selection for crankshaft manufacturing :
Based on the stress imposed on the component during the operation, and
operating temperature, the material to be selected for this component
should has the following characteristics:
• The material should be strong in bending
• It must have excellent fatigue resistance.
• It must have less coefficient of thermal expansion so that the component
can retain its original dimension at varying temperatures.
• The material should be easily machinable so that it can take complex
shape (as required for the geometry of crankshaft) easily.
After carrying out an extensive research of materials, following materials
were listed for crankshaft:
(Aluminum, Copper, and Steel)
5. The way the crankshaft works:-
A crankshaft is a shaft driven by a crank mechanism, consisting of a
series of cranks and crankpins to which the connecting rods of an engine
are attached.[1]
It is a mechanical part able to perform a conversion
between reciprocating motion and rotational motion. In a reciprocating
engine, it translates reciprocating motion of the piston into rotational
motion, whereas in a reciprocating compressor, it converts the rotational
motion into reciprocating motion. In order to do the conversion between two
motions, the crankshaft has "crank throws" or "crankpins" additional bearing
surfaces whose axis is offset from that of the crank, to which the "big ends"
of the connecting rods from each cylinder attach. It is typically connected to
a flywheel to reduce the pulsation characteristic of the four-stroke cycle,
and sometimes a torsional or vibrational damper at the opposite end, to
reduce the torsional vibrations often caused along the length of the
crankshaft by the cylinders farthest from the output end acting on the
torsional elasticity of the metal.

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6- DESIGN OF CRANK SHAFT:-
Number of cylinders=4
Bore diameter (D) = 85 mm
Stroke length (l) = 96mm
Maximum combustion pressure=2.5 N/mm2
We know that force on the piston i,e: gas load
In order to find the thrust in connecting rod we should find out angle of
inclination of connecting rod with line of stroke.
Assume that the distance (b) between the bearings 1 and 2 is equal to twice the
piston diameter (D). b = 2D = 2 × 85 =170mm
Due to this piston gas load (FP) acting horizontally, there will be two horizontal
reactions H1and H2 at bearings 1 and 2 respectively, such that
b1 = b2= 85mm

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Assume that the length of the main bearings to be equal, i.e., c1 = c2 = c / 2. We
know that due to the weight of the flywheel acting downwards, there will be two
vertical reactions V2 and V3 at Bearings 2 and 3 respectively, such that
7. Conclusion :-
• • Crankshaft is one of the key components of automobile engine, the
performance good or bad will directly affect the service life of the car. Crankshaft
is working under heavy load and continuous
• • The crankshaft is an important part in automobile engine, it will cooperate
with connecting rod and change gas pressure rolled in the piston into the rotation
of the power, to the transmission mechanism of underpin, drive distribution
agencies and other auxiliary devices
8. References
• ASM Handbook, Volume 14A - Metalworking Bulk Forming
• ASM HandBook Volume 14 - Forming and Forging, 9th Edition ,1998
• Stress Analysis and Optimization of Crankshafts Subject to Dynamic Loading,
Project report, Farzin H. Montazersadgh and Ali Fatemi , The University of Toledo
, August 2007