Delhi Skill & Entrepreneurship

University
G.B. Pant DSEU Okhla-I Campus
Applied Thermodynamics
Practical File

Submitting to:- Irwin Osmond Toppo

Submitted by:- Sagar Mishra
Roll number:-41622024
Branch:- Mechanical Engineering
Year:- 2nd Year (4th Semester)
 EXPERIMENT- 1

OBJECTIVE:
To study the two-stroke petrol engine.

EQUIPMENTS:
Model of two stroke petrol engine.

THEORY:
Any type of engine or m/c which drives heat energy from the combustion of fuel or any other
source and converts this energy into mechanical work is termed as a heat engine.

Heat engines may be classified into two main classes as follows:

1. Internal combustion engine
2. External combustion engine.

Main Parts of the Petrol Engine:

1. Cylinder & Cylinder Head
2. Piston
3. Piston Rings
4. Gudgeon Pin
5. Connecting Rod
6. Crank Shaft
7. Crank
8. Engine Bearing
9. Crank Case
10.Fly Wheel
11.Governor
12.Valves
13.Spark Plug
14. Carburetor
15.Cam & Cam Shaft

Working Process of Two Stroke Petrol Engine:

In two stroke engine, the working cycle is completed into two stroke of the piston or one
revolution of crankshaft. In two stroke engine the intake and compression processes are
completed during the inward stroke and Expansion & exhaust process during the outward
stroke. In figure shows a two-stroke petrol engine the cylinder L is connected to a closed
crank chamber, during the upward stroke of the piston M, the gases in L are compressed and
at the same time fresh air and fuel (petrol) mixture enters the crank chamber through the
valve V. when the piston moves down wards, V closes and the mixture in the crank chamber
is compressed.
1. The piston is moving upwards & is compressing an explosive charge which has previously
been supplied to L. Ignition takes place at the end of the stroke. The piston then travels
downwards due to expansion of the gases.
2. And near the end of this stroke the piston uncovers the exhaust port (E.P) and the burnt
exhaust gases escape through this port.
3. The transfer port (T.P) then is uncovered immediately and the compressed charge from the
crank chamber flows into the cylinder and is deflected upwards by the hump provided on the
head of the piston. It may be noted that the incoming air petrol mixture helps the removal of
gases from the engine cylinder, if in case these exhaust gases do not leave the cylinder the
fresh charge gets diluted and efficiency of the engine will decreases. The piston then again
starts moving from B.D.C to T.D.C and the charge gets compressed when E.P and T.P are
covered by the piston, thus the cycle is repeated.

Fig 1: Two stroke petrol engine

APPLICATIONS:
1. I.C. engine are used in all road vehicles i.e. automobiles trucks, tractors etc.
2. I.C. engine are widely used in rail road, aviation & marine.
3. I.C. engine are extensively used in lawn movers boats, concretes mining equipments etc.
4. Petrol engine are used in light motor vehicles like scooty.

PRECAUTIONS:
1. Fuel supply should be controlled.
2. It requires running maintenance.
3. Maintain constant speed for better controlled.
 EXPERIMENT NO-02
OBJECTIVE:

To study the two stroke diesel engine.

EQUIPMENTS:
Model of two stroke.

THEORY:

Any type of engine or m/c which drives heat energy from the combustion of
fuel or any other source and converts this energy into mechanical work is
termed as a heat engine.
Main Parts:

1. Cylinder & Cylinder Head

2. Piston
3. Piston Rings
4. Gudgeon Pin
5. Connecting Rod
6. Crank Shaft
7. Crank
8. Engine Bearing
9. Crank Case
10. Fly Wheel
11. Governor
12. Valves
13. Fuel Pump & Injector Unit
14. Cam & Cam Shaft

Working Process of Two Stroke Diesel Engine:

In two stroke engine, the working cycle is completed into two stroke of
the piston or one revolution of crankshaft. In two stroke engine the intake
and compression processes are completed during the inward stroke and
Expansion & exhaust process during the outward stroke. In figure shows a
two stroke diesel engine the cylinder L is connected to a closed crank
chamber, during the upward stroke of the piston M, the gases in L are
compressed and at the same time fresh air enters the crank chamber
 through the valve V. When the piston moves down wards, V closes and
the air in the crank chamber is compressed (in fig.).

1. The piston is moving upwards & is compressing air which has

previously been supplied to L. Injector inject and Ignition takes
place at the end of the stroke. The piston then travels downwards
due to expansion of the gases.
2. And near the end of this stroke the piston uncovers the exhaust
port (E.P) and the burnt exhaust gases escape through this port.
3. The transfer port (T.P) then is uncovered immediately and the
compressed air from the crank chamber flows into the cylinder
and is deflected upwards by the hump provided on the head of the
piston. It may be noted that the incoming air helps the removal of
gases from the engine cylinder. The piston then again starts
moving from B.D.C to T.D.C and the charge gets compressed
when E.P and T.P are covered by the piston, thus the cycle is
repeated.

Fig. 5.1: 2 Stroke diesel engine

APPLICATIONS:

1. I.C. engine are used in steamers etc.

2. I.C. engine are widely used in small engines.
3. I.C. engine are extensively used in lawn movers boats,
concretes mining equipment
 Experiment – 03
OBJECTIVE:
To study the four stroke petrol engine.

APPARATUS USED:
Model of four stroke petrol engine.

THEORY:
Any type of engine or m/c which drives heat energy from the combustion of fuel or any other
source and converts this energy into mechanical work is t termed as a heat engine.
Heat engines may be classified into two main classes as follows:
1. Internal combustion engine
2. External combustion engine
Main Parts of the Petrol Engine:
1. Cylinder & Cylinder Head
2. Piston
3. Piston Rings
4. Gudgeon Pin
5. Connecting Rod
6. Crank Shaft
7. Crank
8. Engine Bearing
9. Crank Case
10. Fly Wheel
11. Governor
12. Valves
13. Spark Plug
14. Carburator
15. Cam & Cam Shaft

Working Process of Otto Four Stroke Engines:

The various stroke of a four stroke (Otto) cycle engine are given below:
Suction Stroke: During this stroke the piston moves from TDC to BDC, the inlet valve open
and proportionate fuel-air mixture is sucked in the engine cylinder. In fig. shown by line 5-1.
Compression Stroke: In this stroke, the piston moves (1-2) towards TDC and compressors
the enclosed fuel air mixture drawn in the engine cylinder during suction. Both the inlet and
exhaust valves remain closed during the stroke.
Expansion Stroke: When the mixture is ignited by the spark plug the hot gases are produced
which drive or through the piston from T.D.C to R.D.C and thus the work is obtained in this
stroke. A spark plug which ignites the mixture & combustion takes place at constant volume
(2-3). Both the valves remain closed during the start of this stroke but when the piston just
reaches the B.D.C the exhaust valve opens.
Exhaust Strokes: This is the last stroke of the cycle. Here the gases from which the work has
been collected become useless after the completion of the expansion stroke and are made to
escape through exhaust valve to the atmosphere. This removed of gas is accomplished during
this stroke. The piston moves from B.D.C to T.D.C and the exhaust gases are driven out of
the engine cylinder. This is also called scavenging. This is represented by the line (1-5).

APPLICATIONS:
1. I.C. engine are widely used in bikes.
2. I.C. engine are extensively used in lawn movers boats etc.
3. Petrol engine are used in light motor vehicles like bike etc.
 EXPERIMENT-04
OBJECTIVE:

To study the four stroke diesel engine.

APPARATUS USED:

Model of four stroke diesel engine.

THEORY:

Any type of engine or m/c which drives heat energy from the combustion
of fuel or any other source and converts this energy into mechanical work is
termed as a heat engine.
Heat engines may be classified into two main classes as follows:
1. Internal combustion engine
2. External combustion engine

Main Parts of the Diesel Engine:

1. Cylinder & Cylinder Head
2. Piston
3. Piston Rings
4. Gudgeon Pin
5. Connecting Rod
6. Crank Shaft
7. Crank
8. Engine Bearing
9. Crank Case
10. Fly Wheel
11. Governor
12. Valves
13. Fuel Pump & Injector Unit
14. Cam & Cam Shaft.

Working Process of Four Stroke Diesel Engines:

The various stroke of a four stroke diesel cycle engine are given below:

Suction Stroke: During this stroke the piston moves from TDC to
BDC, the inlet valve open and proportionate air is sucked in the engine
cylinder. In fig. shown by
 Fig. 6.1: 4-Stroke Diesel Engine

Compression Stroke: In this stroke, the piston moves (1-2) towards TDC
and compressors the enclosed fuel air drawn in the engine cylinder during
suction. Both the inlet and exhaust valves remain closed during the stroke.

Expansion Stroke: When the fuel is ignited by the spark plug the hot gases
are produced which drive or through the piston from T.D.C to B.D.C and
thus the work is obtained in this stroke. A injector which inject and &
combustion takes place at constant pressure (2-3). Both the valves
remain closed during the start of this stroke but when the piston just
reaches the B.D.C the exhaust valve opens.
Exhaust Stroke: This is the last stroke of the cycle. Here the gases
from which the work has been collected become useless after the
completion of the expansion stroke and are made to escape through exhaust
valve to the atmosphere. This removed of gas is accomplished during this
stroke. The piston moves from B.D.C to T.D.C and the exhaust gases are
 line driven out of the engine cylinder. This is also called scavenging. This is
represented by the (1-5).

APPLICATIONS:

1. I.C. engine are used in all road vehicles i.e. automobiles trucks,
tractors etc
2 I.C. engine are widely used in rail road, aviation & marine.
3 I.C. engine are extensively used in lawn movers boats, concretes mining
equipments.
 EXPERIMENT NO-5

OBJECTIVE: -To draw valve Timing diagram of a diesel engine and study of its impact on the
performance of an IC engine.

THEORY:- A valve-timing diagram is a graphical representation of the exact moments, in the

sequence of operations, at which the two valves (i.e. inlet and exhaust valves) open and close as well
3s firing of the fuel. It is, generally, expressed in terms of angular positions of the crankshaft.

1. Theoretical Valve Timing Diagram for Four Stroke Petrol Cycle Engine:

The theoretical valve timing diagram for a four-stroke cycle engine is Shown in Fig. I In this diagram,
the inlet valve opens at A and the suction takes place from A to B. The crankshaft revolves through
180° and the piston moves from T.D.C. to B.D.C. At B, the inlet valve closes and the compression
takes place from B to C. The crankshaft revolves through 180° and the piston moves from B.D.C. to
T.D.C. At C, the fuel is fired and the expansion takes place from C to D. The crankshaft revolves
through 180° and the piston again moves from T.D.C. to B.D.C. At D, the exhaust valve opens and
the exhaust takes place from D to E. The crankshaft again revolves through 180° and the piston moves
back to T.D.C. In four- stroke cycle, the crank revolves through 180° and the piston moves back to
T.D.C. In four-stroke cycle, the crank revolves through two revolutions

2. Valve Timing Diagram for A Four-Stroke Cycle Diesel Engine :-

In the valve timing diagram as shown in Fig. we see that the inlet valve open before
the piston reaches TDC; or in other words while the piston is still moving up before the beginning of
the suction stroke. Now the piston reaches the TDC and suction stroke starts. The piston reaches the
BDC and then starts moving up. The inlet valve closes, when the crank has moved a little beyond the
BDC. This is done as the incoming air continues to flow into the cylinder although the piston is
moving upwards from BDC. Now the air is compressed with both valves closed. Fuel valve opens a
little before the piston reaches the TDC. Now the fuel is injected in the form of very fine spray, into
the engine cylinder, which gets ignited due to high temperature of the compressed air. The fuel valve
closes after the piston has come down a little from the TDC. This is done as the required quantity of
fuel is injected into the engine cylinder. The burnt gases (under high pressure and temperature) push
the piston downwards, and the expansion or working stroke takes place
Now the exhaust valve opens before the piston again reaches BDC and the burnt gases start leaving
the engine cylinder. Now the piston reaches BDC and then starts moving up thus performing the
exhaust stroke. The inlet valve opens before the piston reaches TDC to start suction stroke. This is
done as the fresh air helps in pushing out the burnt gases. Now the piston again reaches TDC. and the
suction starts. The exhaust valve closes when the crank has moved a little beyond the TDC. This is
done as the burnt gases continue to leave the engine cylinder although the piston is moving
downwards.

TDC: Top Dead Centre

BDC: Bottom Dead Centre
IVO: Inlet Valve Opens (10°-20° before TDC)
IVC: Inlet Valve Closes (25° 40° after BDC)
FVO: Fuel valve opens (10°-15° before TDC)
FVC: Fuel valve closes (15°-20° after TDC)
EVO: Exhaust Valve Opens (39°-50° before BDC)
EVC: Exhaust Valve Closes (10-15° after TDC)
PERFORMANCE TEST OF A 4-STROKE
SINGLE CYLINDER DIESEL ENGINE

OBJECTIVES:
i. To conduct a load test on 4-stroke, single cylinder diesel engine to study its
performance under various loads.
ii. To plot the following engine performance graphs based on the experiment
write/describe the parts.

APPARATUS:
i. Test engine bed
ii. Stop Watch

THEORY:
Single cylinder stationary diesel engines that operate at a consistent speed are typically
regulated for quality performance. Unlike spark-ignition engines, where air intake is
controlled through throttling, these diesel engines maintain a steady flow of air to the
combustion chamber. Instead of adjusting air intake, the engine's power output is managed by
controlling the amount of fuel injected into the cylinder. This injection process is facilitated
by a fuel pump equipped with a rack mechanism, which allows for variable fuel delivery. The
rack can be controlled either automatically by a governor system or manually by hand.
Despite variations in power demand from the engine's output shaft, the airflow rate into the
cylinder remains relatively constant. This stability in airflow ensures consistent combustion
conditions within the cylinder. However, the amount of fuel injected varies proportionally
with the power demand. Consequently, as the engine output increases, the fuel-to-air ratio
rises accordingly. This linear relationship between power output and fuel consumption affects
the combustion process, influencing factors such as efficiency and emissions.

PROCEDURE:
1. Prior to commencing the test, it was ensured that the Test Engine Fuel Tank contained
an ample supply of fuel.

2. The operator proceeded to activate both the electrical and water supplies connected to
the engine Test Bed.
3. Deliberate action was taken to open the fuel taps on the fuel gauge, facilitating the
unhindered flow of fuel to the Test engine. Any potential presence of air bubbles
within the fuel line was diligently addressed through tapping.

4. The engine's speed control, known as the engine rack, was meticulously adjusted to a
position midway between its extremes.

5. The operator carefully pulled out the engine start handle until encountering resistance,
indicating the engine's readiness to start, and then gradually released it back to its
original position.

6. Ensuring stability, the operator positioned themselves with both hands firmly grasping
the starter handle.

7. With determination, the starting handle was pulled out firmly and swiftly, with the
expectation that the engine would spring to life. The operator maintained contact with
the starting handle as it returned to its resting position adjacent to the engine, then
released it.

8. In the event of the engine failing to start, steps 5, 6, and 7 were repeated as necessary
to troubleshoot the issue.

9. Subsequent to successful ignition, the engine was allowed to run uninterrupted for
several minutes, affording it the opportunity to attain and stabilize at its normal
operating temperature. This critical phase ensured that the engine functioned
consistently and reliably.
 EXPERIMENT – 7
1. OBJECTIVE: - Performances Analysis of a four stoke four cylinder Petrol Engine.

2. APPARATUS REQUIRED:- Digital RPM indicator to measure the speed of the engine.
Digital temperature indicator to measure various temperatures. Differential manometer to
measure quantity of air sucked into cylinder. Burette with manifold to measure the rate of
fuel consumed during test.

3. THEORY:- A Petrol Engine is an internal combustion engine in which the combustion of

a fuel (normally a fossil fuel) occurs with an oxidizer (usually air) in a combustion
chamber. In an internal combustion engine the expansion of the high-temperature and
pressure gases produced by combustion applies direct force to some component of the
engine, such as pistons. This force moves the component over a distance, generating
useful mechanical energy.The effect of water injection on a spark ignition engine thermal
balance and performance has been experimentally investigated on a four stroke four
cylinder engine with LPG (liquid petroleum gas) as fuel. The results showed that as the
water injection level to the engine increased, the percentage of useful work increased,
while the losses other than unaccounted losses decreased. Moreover, the specific fuel
consumption decreased, while the engine thermal efficiency increased. A theoretical
study of different strategies for waste heat recovery in an internal combustion engine run
by internal combustion and electric motor was conducted to reduce specific fuel
consumption [2]. The important applications of I.C. engines are road vehicles,
locomotives, ships and aircraft, portable standby units for power generation in case of
scarcity of electric power, extensively used in farm tractors, lawn movers, concrete
mixing devices and motor boats etc.Thus, aim of this paper is to study the best
performance condition of a practical ISUZU Engine.

4. THE SPECIFICATIONS OF THE SAID ENGINE ARE GIVEN BELOW:-

Ø Brake Horse Power : 10HP

Ø No of cylinder : 4
Ø Compression ratio : 8.5:1
Ø Bore Diameter : 84mm
Ø Stroke length : 82mm
Ø Types of cooling : water cooling
Ø Air drum orifice diameter : 24mm
Ø Speed : 1500rpm
 Ø Load arm : 320mm
Ø Maker : ISUZU

Schematic diagram of the experimental test rig of Petrol Engine (ISUZU Engine)

5. ANALYSIS OF ENGINE PERFORMANCE:-

The engine performance is indicated by the term efficiency η. The heat energy which is
converted to power is called indicated power, IP it is utilized to drive the piston. The useful
energy available at the shaft is called brake power BP. The fuel consumption characteristics of an
engine are generally expressed in terms of specific consumption in kg of fuel per kilowatt-hour.
It is an important parameter that reflects how good the engine performance is. The relationship
between speed, power developed and specific fuel consumption determines the performance of
an engine.

5.1 POWER AND MECHANICAL EFFICIENCY

The power developed by an engine and measured at the output shaft is called
the brake power (BP) and is
given by:-
 5.2 VOLUMETRIC EFFICIENCY
It is defined as the ratio of the mass of air inducted into the engine cylinder
during the suction stroke to the
mass of the air corresponding to the swept volume of the engine at

atmospheric pressure and temperature.

5.3 FUEL-AIR RATIO (F/A)

Fuel-air ratio of the mixture affects the combustion phenomenon in that it
determines the flame propagation
velocity, the heat release in the combustion chamber, the maximum
temperature and the completeness of
combustion.

5.4 SPECIFIC FUEL CONSUMPTION

Specific fuel consumption is defined as the amount of fuel consumed for
each unit of power developed per
hour. It is a clear indication of the efficiency with which the engine develops
power from fuel.

6. RESULTS AND DISCUSSIONS:-

Experimental results obtained on five different loads in form of water thrust of the Petrol
engine are discussed in the following paragraphs:

6.1 VARIATION OF EFFICIENCY WITH VARIATION OF AIR FUEL

RATIO:-
The Below fig. describe the variation of efficiency(ɳ) with the variation of air
fuel ratio(A: F). Initially efficiency increases linearly as the A:F ratio increases
and maximum efficiency of 31.28 % was observed at 16.3:1 (A:F) which is
slightly lean mixture. This Air : Fuel ratio (16.3:1) is very important from point of
fuel economy and also, less pollution. Complete combustion of fuel is possible at
this air fuel ratio when other parameter like rpm is 1568 and BHP is 9.85.
6.2 VARIATION OF POWER OUTPUT (HP) WITH THE VARIATION
OF AIR FUEL RATIO(A:F):-
The below fig. describes the variation of power output(HP) with the variation of
air fuel ratio(A:F). The A:F ratio at which an engine operates has a considerable
influence on its power output. Initially when A:F mixture is rich i.e. Air is less
compared to stoichiometric Air:Fuel ratio very less oxygen is available for
sufficient combustion and hence, engine produces less power. After that power
output increases with increases in A:F ratio due to availability of more oxygen for
burning. Maximum power was observed to be 12 HP at the A:F ratio 12.3:1
which is slightly richer than the stochiometric mixture.The oxygen available in
the limited air inside the cylinder is fully utilized for combustion. Dissociation is
less as CO is already present in the product of combustion and thereby, power is
highest at rich mixture.Therefore to get maximum power from the engine it
should be run at 12.3:1 A:F ratio.
6.3 VARIATION OF VOLUMETRIC EFFICIENCY WITH VARIATION
OF POWER OUTPUT
Volumetric efficiency is a very important parameter for longevity and overall
health of the engine. It also indicates the breathing ability of the engine. Here
volumetric efficiency is maximum at brake power of 2 HP when rpm of engine is
very low due to the fact that number of opening and closing of valves per unit
time is less and hence, time involved in opening and closing is less. Operation of
valves need some time to fully open the inlet. With increase in speed, the cycle
time decreases and within the short span opening of valves are disturbed and
cylinders are not fully filled with outside air and thereby, volumetric efficiency
decreases. Moreover, at higher speed throttle valve of carburetor is fully open and
hence at maximum power of 12 HP more air enter due to inertia of velocity and
volumetric efficiency is medium (45.03 %). Therefore to get longevity of engine
running at lower power is necessary and at urgency, maximum power is suitable.

6.4VARIAT ION
OF POWER OUTPUT WITH VARIATION OF RPM

The below fig. describes variation of power output with the variation of speed
(RPM). Brake power output of the engine is almost linearly proportional to speed
of the engine. Number of cycles per unit time increases with increase in RPM.
Hence, power output increases with the increase in rpm. Here we observed that
highest brake power output(9.85HP) obtained when engine running at speed of
1568 RPM. Although, all engine have certain limit, where it gives highest power
at a particular speed. So, always engine should run within its speed limit.
Otherwise it may damage any time.
 EXPERIMENT – 8
OBJECTIVE
To test the performance of reciprocating air compressor.
EQUIPMENT
Reciprocating air compressor
THEORY
A reciprocating compressor is a positive-displacement air compressor that converts power
into potential energy stored as compressed air using electric motors, diesel or gasoline
engine, among others as it’s prime-mover. It uses piston driven by a crankshaft to deliver
fluid (gases or air) at high pressure. The intake atmospheric air enters through the suction
valve, then flows into the compression chamber where it is compressed by a piston driven in
a reciprocating motion by means of a crankshaft.
The compressed air contains energy which can be employed for a variety of applications such
as operating tools in factories, operating drill and hammers in road building, excavating,
inflating of tyre, drying, spray painting among other by utilizing the kinetic energy of the air
as it is released and the tank depressurizes.
a) When the gas is compressed according to low.PVn = Constant Work req /cycle
W = P2V2+(P2V2-P1V1 /n-1) – P1V1 = [(nP2V2-P2V2)+(P2V2-P1V1)-(nP1V1-
P1V1)]/ n-1 = n (P2V2-P1V1) / n-1 W = P1V1n / n-1 (P2V2 / P1V1-1) P1V1 n =
P2V2 n V2 / V1= (P1 /P2) -1/n W =P1 V1 n / n-1[(P2 / V1).(P2 / P1) -1 / n -1] W
= P1 V1 n / n-1[(P2 / V1) n-1 /n -1] KJ / cycle
(b) When gas is compressed adiabatically:- W = P1V1r / r-1 [(P2 / V2) r-1 / r -1] Kj / cycle
(c) When gas is compressed isothermally:-W = P2V2log eV1 / V2 or P1V1log e V1 / V2 KJ/
Cycle P1 & P2 are in KN / m2 & V1 & V2 are in m3

Reciprocating air compressors can be classified in two types:

1) Single-acting reciprocating air compressor
2) Multi-acting reciprocating air compressor
The aim of this study is to employ thermodynamic concepts in the analysis of the
performance of a single –acting reciprocating air compressor design and manufactured using
locally available materials. The reciprocating compressor is to be used for practical
demonstration in the mechanical engineering laboratory during Fluid Machinery, Applied
Fluid Mechanics and Thermodynamics classes. The compressor will also be employed in
workshops and places where pressurized air is required such as for tyre inflation, dust
cleaning and spray-painting among others.

PROCEDURE
1. Check the necessary electrical connections and also for the direction of
the motor.
2. Check the lubricating oil level in the compressor.
3. Start the compressor by switching on the motor.
4. The slow increase of the pressure inside the air reservoir in observed.
5. Maintain the required pressure by slowly operating the discharge valve (open/close).
(Note there may be slight variations in the pressure readings since it is a dynamic
process and the reservoir will be filled continuously till the cut-off.)
6. Now note down the following readings in the respective units, speed of compressor,
Manometer readings.
7.Delivery pressure. Temperatures. Energy meter reading.
8. Repeat the experiment for different delivery pressures.
9. Once the set of readings are taken switch of the compressor.
10. The air stored in the tank is discharged. Be careful while doing so, because the
compressed air passing through the small area also acts as a air jet which may damage you
or your surroundings.
11. Repeat the above two steps after every experiment.