this lab report include details and demonstrations about internal combustion ( IC) engine. its types like CI and SI engines, different parts of engine, 2 stroke and 4 stroke engine. The ignition system of engine, cooling system of Engine and lubricating system of Engine in detail.

1. University of Engineering and Technology Peshawar, Pakistan
Mechanical
Technology lab
Report
Prepared by Muhammad Bilal
First Year- CED Uet Peshawar, Pakistan
Contact: bilal.akhund9@gmail.com

2. 1
Table of Contents
Name of Demonstration Page number
To demonstrate and Practically
Understand Different
Components of Internal
Combustion Engine (IC Engine)
2
Demonstration of 2 and 4 stroke
Engine
4
Determination and difference
between Petrol and Diesel
Engine
7
Demonstration of Ignition
system of Engine
10
Determination of cooling system
Of Engine
12
Determination of Lubricating
System of Engine
14

3. 2
Lab # 1
To demonstrate and Practically Understand Different Components
of Internal Combustion Engine (IC Engine)
Abstract
There are 3 types of Gasoline Engines namely, The 4 Stroke Petrol Engine, The 4 Stroke
Diesel Engine and The 2 Stroke Petrol Engine. All of these are IC engines; we will here
know the basic Function and working of different Components.
Theoretical background
 Internal combustion Engine
 External Combustion engine
 Reciprocating Engine
 Rotary Engine
Main Components of IC Engine
Engine block
In this all the components are installed it is made from cast iron
Cylinder
It is actually the main body of the engine in which the piston moves linearly. It also
contains or holds the gases or fuels which are to be burned.
Piston
Known as heart of the engine, it is used to transfer energy it has to and fro motion
Piston Rings
1. Compression rings 2. Oil control/lubricating Rings

4. 3
Compression Rings: These are the rings which are present on the upper cuts of the piston.
They prevent the air-fuel mixture from leaking.
Lubricating Rings: These are present on the lower cuts of the piston. They bring engine oil
from the crank case and lubricate the sides of the cylinder
Inlet Valve: It is the valve through which the air-fuel mixture enters into the cylinder.
Exhaust Valve: It is the valve through which exhaust or burned gases go out from the
cylinder
Spark plug
It is the plug which gets power from the supply and produces spark during the ignition
stroke
Fly wheel
It is the dead weight which absorbs energy during the power stroke and utilizes it in the
remaining three strokes
Cam shaft
On the shaft are mounted CAMs which control the opening and closing of the Inlet and
Outlet valves

5. 4
Lab # 2
Demonstration of 2 and 4 stroke Engine
Objective
To understand the working/operational difference between 2-stroke and 4-stroke engine
Background
A Stroke is defined as the distance between Upper and Lower Dead Center. The Upper
Dead Centre is the highest position that the piston can reach in the cylinder while the
Lower Dead Centre is the lowest position that the piston can reach in the cylinder.
In the 4 Stroke Petrol Engine there are 4 strokes while there are two strokes in two
strokes engine. Their working operation is very different from each other.
What is a stroke?
A stroke refers to the full travel of the piston along the cylinder, in either direction. Or the
moment of the piston from top dead center to bottom dead center.
What is compression ratio?
= maximum volume/minimum volume
= (clearance volume + swept volume)/clearance volume
For petrol engines it is usually 10:1 and for diesel Engine it is 22:1
Swept volume=

6. 5
Working of 4 Stroke Petrol Engine:
1) Intake Stroke:
The inlet valve is opened and the fuel/air mixture is drawn in as the piston travels
down.
2) Compression Stroke:
The inlet valve is closed and the piston travels back up the cylinder compressing
the fuel/air mixture. Just before piston reaches the top of its compression stroke a
spark plug emits a spark to combust the fuel/air mixture.
3) Combustion Stroke:
The piston is now forced down by the power produced by the combustion of the
fuel air mixture. The engines power is derived from this stroke.
4) Exhaust Stroke:
The exhaust valve is opened and the piston travels back up expelling the exhaust
gases through the exhaust valve. At the top of this stroke the exhaust valve is
closed. This process is then repeated.

7. 6
Working Of Two Stroke Engine
In a two stroke engine the stroke starts with the piston at the lower dead center
1st stroke:
The piston is at the bottom of the cylinder. A pipe at the left side is opened and lets the
fuel mixture, which is already compressed a bit, flow from the lower to the upper part of
the cylinder. The fresh gases expulse now the exhaust through an ejection pipe.
2nd stroke:
After being hurried upward, the piston now covers the pipe on the left side and the
ejection pipe. Because there is no way out any more, the upper, fresh gas mixture gets
compressed now. At the same time in the part below fresh gas is taken in by the piston
driving upward through the open suction pipe. At the upper dead-center, the compressed
fuel mixture is ignited by the sparking plug, the piston is pressed downward while it
compresses at the same time the fresh gas below. The process begins again as soon as the
piston arrives at its lowest point.

8. 7
Lab # 3
Determination and difference between Petrol and Diesel
Engine
Objective
 To understand the working of Compression Ignition (CI) and Spark Ignition(SI)
Engines
 To study difference between CI and SI Engines
 Advantages and dis-advantages of CI and SI Engines
Theory OF IC Engines (CI and SI)
IC engines may operate on a 4 stroke cycle or a 2 stroke cycle. In a 4 stroke cycle the
piston has to go through 4 strokes in order to complete cyclic thermodynamic processes.
In the 2 stroke cycle the piston goes through only 2 strokes to complete the cycle. This
seems to make the 2 stroke cycle more advantageous. 2 stroke cycles is applied more to
marine type slow and large CI engines and to light SI engines used on motorcycles and
lawn mowers, etc.
Working of SI Engines:
Spark ignition engines are mainly used in automotive vehicles such as automobiles and
motorcycles. These engines cannot be very big in size because of auto ignition. They
induce a mixture of air and fuel during the induction process and then compress the
induced charge to a pressure of approximately 12-15 atmospheres and a temperature of
500-600 K during the compression process and towards the end of the compression
process the hot and compressed mixture is ignited by a spark produced by the electrical
ignition system of the engine.
Working of CI Engines
Compression ignition engines have a much broader field of application. It's possible to
produce approximately 2000 kW per cylinder as well as 0.2 kW per cylinder with this type

9. 8
of engine. Since they can operate at much higher powers than SI engines they are more
suitable for commercial applications.
Liquid fuel is injected into the cylinder towards the end of compression. The fuel spray
atomizes into small droplets, evaporates and mixes with hot air. Then it auto ignites after
compression stroke Once combustion starts, the remaining fuel rapidly evaporates and
enters the combustion reaction. During all this the injection of fuel is still continuing.
Difference between CI and SI Engines:
SI Engine CI Engine
Constant volume Constant Pressure
Petrol is volatile Diesel is heavy and bulky
It has spark plug No spark plug. it has glow plug ( in
winter to warm cylinder)
Low compression ratio ( 5:1 to 10:1) High compression Ratio ( 18:1 to
22:1)
Petrol efficiency 30% Diesel efficiency 40%
High power and low torque High thermal efficiency, high torque

10. 9
Advantages and disadvantages of SI and CI Engines:
SI Engine (Advantages)
 Engine feels nice and smooth. Its light and easy to drive
 Small initial and low maintenance cost
 Silent drive- engines don't produce much noise.
 Low on emissions hence environment friendly
Disadvantages:
 Torque is less , hence pulling power is less
 Overall fuel efficiency is a bit less as compared to a diesel counterpart.
CI Engine (advantages)
 High torque output hence pulling power is high (acceleration is good).
 Fuel efficiency is high as compared to petrol counterpart. They are more efficient.
 Service requirement is less frequent.
 low NOx emissions
Disadvantages
 Overall cost of the car with diesel engine is high on the pocket.
 Engine is grunt and generally produces more noise than petrol ones.
 Cars with diesel motors have high initial investment

11. 10
Lab # 4
Demonstration of Ignition system of Engine
Objective
 To study various components of Ignition system
 To understand control and timed ignition
Background
The system which ignites the air fuel mixture to form a spark, due to which power is
produced and component of engine runs.
Function of ignition system
 To control spark and to control its timings.
 To increase voltage from 12V to 20KV
Components of Ignition system
Battery:
The battery is the source of electrical energy needed to operate the ignition system. The
battery stores and produces electricity through chemical action. From 12V to 14V
Ignition coil
An ignition coil is actually a step up transformer and electromagnet having two types of
windings. 1. Primary windings 2. Secondary windings
Function
of battery
is "SLI"
Starting
IgnitingLighting

12. 11
Control Breaker
The purpose of the contact/control breaker is to interrupt the current Flowing in the
primary circuit of the ignition.
Capacitor
Wired in parallel with the contact points and grounded through the distributor housing. It
prevents burning; it provides a place where current can flow.
Spark plug
It receives a high voltage spark from secondary coil through rotor and outer terminal
having two electrodes.
1. Central electrodes 2. Ground electrodes
Distributer: As name indicates, it distributes electric current.
Ignition switch
The primary circuit starts at the battery and Flows to the ignition switch. It controls the
Flow of electricity across the terminals.

13. 12
Lab # 5
Determination of cooling system Of Engine
Objective
 To study the main component Of Cooling System
 To understand how to Remove surplus heat and maintain optimum temperature

Theory
During combustion process engine produces tremendous amount of heat. That amount of
heat is dissipated in different areas.
 1/3 of heat goes as exhaust gases
 1/3 of heat is converted to mechanical energy
 1/3 of heat is observed by engine component
Main Components of Cooling System
Radiator
The radiator core is usually made up of Aluminum with aluminum strips that zigzag
between the tubes. These fins transfer the heat in the tubes into the air stream to be
carried away from the vehicle.
Thermostat
The thermostat regulates the flow of coolant into the engine keeping it at its optimum
operating temperature. The thermostat is closed when the engine is cold.
Radiator cap/Pressure cap
The radiator cap is responsible for maintaining the proper amount of cooling system
pressure. If the amount increases above the set pressure point, a spring-loaded valve in
the cap releases extra Pressure.
Water jacket
These are passage inside engine which allows coolant to flow inside engine.

14. 13
Water Pump
The water pump is considered the ‘heart’ of the cooling system and is usually located on
the front of the cylinder block. The water pump has fan-like blades on an impeller that
spins, creating centrifugal force, moving the liquid outward. Coolant is routed through the
engine.
The coolant then absorbs heat from the engine components and, once hot, leaves the
engine and enters the radiator.
Fans
It draws the air inside the engine by passing air through radiator which cools down the
temperature of coolant.

15. 14
Lab # 6
Determination of Lubricating System of Engine
Objective:
 To Study main components
 To Understand how lubricating oil keep the Engine clean and cool
Theory
The lubricant reduces friction between Engine parts .Generally different grades of oils are
used like single grade or multi grade oil both have its advantages.
Parts of lubricating system
Oil sump/pan
It is used to store oil. And helps in cooling the oil Pan gasket splits if over tightened
Oil pump
Operated through crank shaft
Oil pressure indicator
The light turns on or gauge reads low when the pressure drops below 10psi.Commom case
of low Pressure is low oil level. Good oil pressure is 40-60 psi
Oil filter
It filters the oil
Oil Galleries or oil lines
These are like water jackets they are small in size.

16. 15
Properties of good Lubricant
 It must have high boiling point
 Low freezing point
 Free from impurities
 Average cost and more Durable
 It should must be thermally stable
Lubricating system of Engine
X
Muhammad Bilal
Student at UET Peshawar,Pakistan