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THERMAL ENGINEERING LAB MANUAL (For III Year B. Tech I Semester (R-14), Mechanical Engineering)

DEPARTMENT OF MECHANICAL ENGINEERING

SRI VENKATESWARA COLLEGE OF ENGINEERING AND TECHNOLOGY

(AUTONOMOUS)

R. V. S. NAGAR, CHITTOOR-517127.

Name of the student: _____________________________

Roll Number: ______________ Branch: ______________

Name of the Laboratory: __________________________

Year & Sem: _______________ Academic Year: _______

THERMAL ENGINEERING LAB MANUAL LIST OF EXPERIMENTS

1. Determination of Viscosity of lubricating oil using

i. Redwood Viscometer –I

ii. Redwood Viscometer –I

iii. Say bolt Viscometer.

2. Determination of Flash point and fire point of sample fluid using

i. Abel’s apparatus

ii. Pensky Marten’s apparatus.

3. Study of Bomb and Junker’s gas calorimeter to determine the Calorific value of fuels.

4. Study of the constructional details & working principles of two-stroke/ four stroke

petrol/diesel engine and to draw

i.Valve Timing Diagram

ii. Port Timing Diagram

5. Performance test on two stage reciprocating Air compressor.

6. Performance test and Preparation of Heat balance sheet on 4-stroke, single cylinder

diesel engine.

7. Retardation test on 4-stroke, single cylinder diesel engine

8. Morse test on 4-stroke, 4- cylinder petrol engine.

9. Performance test on 2- stroke, single cylinder petrol engine.

10. Performance test on refrigeration test rig.

11. Assembly and Disassembly of IC engines.

INDEX

S. No

Date Name of the Experiment Page No:

Signature of the

Faculty

AIM

To determine the viscosity in Redwood seconds of the given sample of oil and to

plot the variation of Redwood seconds, kinematic and dynamic viscosity with temperature. APPARATUS

o Redwood viscometer-I,

o Stopwatch,

o Thermometer (0-1100C)

o Measuring flask. (50 c.c.) THEORY

The viscosity of given oil is determined as the time of flow in Redwood seconds. The

viscosity of a fluid indicates the resistance offered to shear under laminar condition.

Dynamic viscosity of a fluid is the tangential force on unit area of either of two parallel

planes at unit distance apart when the space between the plates is filled with the fluid and

one of the plate’s moves relative to the other with unit velocity in its own plane. The unit of

dynamic viscosity is dyne-sec/cm2. Kinematic viscosity of a fluid is equal to the ratio of the

dynamic viscosity and density of the fluid. The unit of kinematic viscosity is cm2/sec. DESCRIPTION

Redwood viscometer-I consists of a water bath and oil bath, both provided with two

thermometers inside them. There is a ball valve, which is located at center of oil bath to

flow of oil through the orifice. A heater with regulator is fixed for heating purpose.

PROCEDURE

1. Clean the oil cup with a suitable solvent thoroughly and dry it using soft tissue paper.

2. Keep the ball valve in its position so as to keep the orifice closed.

RREEDD WWOOOODD VVIISSCCOOMMEETTEERR-- II

3. The water is taken into the water bath and the oil whose viscosity is to be

determined is taken into the oil cup up to the mark.

4. Note down the time taken in Redwood seconds for a collection of 50 cc . of oil

with a stopwatch at the room temperature without supply of electric supply.

5. Heat the bath and continuously stir it taking care to see that heating of the bath is

done in a careful and controlled manner.

6. When the desired temperature is reached, place the cleaned 50 c.c. Flask below

the orifice in position.

7. Remove the ball valve and simultaneously start a stopwatch. Note the time of

collection of oil up to the 50 c.c. Mark.

8. During the collection of oil don’t stir the bath. Repeat the process at various

temperatures.

OBSERVATIONS

Time for Kinematic

Absolute

viscosity

Oil collecting

Density () Viscosity

A t B

S. No. Temperature 50 c.c. of

gm

OC oil

t sec dyne sec/ cm 2

cm 2/ sec

sec

Where

A = 0.0026 cm2/sec2

B = 1.72 cm 2

GRAPHS TO BE DRAWN

1. Redwood seconds Vs . temperature

2. Kinematic Viscosity Vs . temperature

3. Absolute Viscosity Vs . temperature

MODEL GRAPHS

Te

mp

Redwood seconds Kinematic Viscosity Absolute Viscosity

PRECAUTIONS

1. Stir the water continuously so that the temperature of the oil and water are equal.

2. Before collecting the oil at a temperature, check whether the oil is up to the Indicator

in the oil cup.

3. Always take the readings at a stable temperature

4. Ensure proper setting of the ball valve to avoid leakage

RESULT Variation of Redwood seconds, absolute viscosity and Kinematic viscosity with

temperature, were observed and found to be decreasing with temperature.

AIM To determine the viscosity in redwood second of the given samples of oil and to plot the

variation of Redwood seconds, kinematic and dynamic viscosity with temperature. INSTRUMENTS: Redwood

viscometer-II, Stopwatch,

Thermometer (0-1100C),

Measuring flask. (50 c.c.) THEORY The viscosity of given oil is determined as the time of flow in redwood seconds. The






dynamic viscosity and density of the fluid. The unit of kinematic viscosity is

cm 2

sec DESCRIPTION Redwood viscometer-II consists of a water bath and oil bath, both provided with two


flow of oil through the orifice. A heater with regulator is fixed for heating purpose. PROCEDURE


2. Keep the ball valve in its position so as to keep the orifice closed.



RREEDD WWOOOODD VVIISSCCOOMMEETTEERR-- IIII

4. Before switch on the electric supply, at room temperature note down the time taken

in Redwood seconds for a collection of 50 c.c. of oil with a stopwatch.



6. When the desired temperature is reached, place the cleaned 50 c.c. flask below the

orifice in position.

7. Remove the ball valve and simultaneously start a stopwatch.

8. Note the time of collection of oil up to the 50 c.c. Mark.

9. During the collection of oil don’t stir the bath.

10. Repeat the process at various temperatures.

OBSERVATIONS

\

Time for

Kinematic Absolute

viscosity

Density Oil collecting

Viscosity

B () S. No. Temperature 50 c.c. of A t

0C oil t gm/sec dyne sec/ cm 2

cm 2/ sec

sec

Where

A = 0.0272 cm2/sec2 B = 11.2 cm 2

GRAPHS TO BE DRAWN

1. Redwood seconds vs. temperature

2. Kinematic Viscosity vs. temperature

3. Absolute Viscosity vs. temperature

MODEL GRAPHS

Te

mp


PRECAUTIONS


2. Before collecting the oil at a temperature, check whether the oil is up to the

Indicator in the oil cup.

3. Always take the readings at a stable temperature

4. Ensure proper setting of the ball valve to avoid leakage

RESULTS

Variation of Redwood seconds -II, absolute viscosity and Kinematic viscosity with

temperature, were observed and found to be decreasing with temperature

AIM

To determine the viscosity in Saybolt seconds of the given sample of oil and to plot

the variation of Saybolt seconds, kinematic and dynamic viscosity with temperature. INSTRUMENTS

o Saybolt viscometer,

o Stop watch,

o Thermometer (0-1100C),

o Measuring flask (60 cc) THEORY

The viscosity of given oil is determined as the time of flow in Saybolt seconds. The






dynamic viscosity and density of the fluid. The unit of kinematic viscosity is

cm 2 sec .

DESCRIPTION

Saybolt viscometer consists of a water bath and oil bath, both provided with two


flow of oil through the orifice. A heater with regulator is fixed for heating purpose.

PROCEDURE


2. Keep the cork in its position so as to keep the orifice closed.



SSAAYYBBOOLLTT VVIISSCCOOMMEETTEERR

4. Before switch on the electric supply, at room temperature note down the time

taken in Saybolt seconds for a collection of 60 c.c. of oil with a stop watch.



6. When the desired temperature is reached, place the cleaned 60 c.c. flask below

the orifice in position.

7. Remove the cork valve and simultaneously start a stopwatch. Note the time of

collection of oil up to the 60 c.c. Mark.

8. During the collection of oil don’t stir the bath.

9. Repeat the process at various temperatures.

OBSERVATIONS

Time for

Kinematic Absolute

viscosity

Density Oil collecting

Viscosity

B () S. No. Temperature 50 c.c. of A t

0C oil t gm dyne sec/ cm 2

cm 2/sec sec

sec

Where

A= 0.00226 cm2/sec2

B=1.8 cm 2

GRAPHS TO BE DRAWN

1. Saybolt seconds vs. temperature

2. Kinematic Viscosity vs. temperature

3. Dynamic Viscosity vs. temperature

MODEL GRAPHS

Te

mp


Tem p

PRECAUTIONS


2. Before collecting the oil at a temperature, check whether the oil is up to the level.

3. Always take the readings at a stable temperature.

4. Ensure proper setting of the cork to avoid leakage.

RESULT Variation of Saybolt Seconds, Absolute viscosity and Kinematic viscosity with temperature,

were observed and found to be decreasing with temperature.

AIM

To determine the flash and fire point of the given sample of oil using Abel’s

apparatus closed cup methods. APPARATUS

Abel’s apparatus, Thermo meter (0-110oC). THEORY

This method determines the closed cup flash and fire points of petroleum products

and mixtures to ascertain whether they give off inflammable vapours below a certain

temperature. FLASH POINT: It is the lowest temperatures of the oil, at which, application of test flame causes the vapour

above the sample to ignite with a distinct flash inside the cup. FIRE POINT: It is the lowest temperature of the oil, at which, application of test flame causes burning for

a period of about five seconds. DESCRIPTION

The apparatus consists of a brass cup and cover fitted with shutter mechanism, test

flame arrangement, hand stirrer, thermometer socket. The brass cup is heated by water

bath (with energy regulator), fitted with a funnel and overflow pipe. PROCEDURE

1. Clean the oil cup and fill the up to the mark with the sample oil.

2. Insert the thermometer into the oil cup through the provision to note down the oil

temperature.

3. Using the Energy regulator, control the power supply given to the heater and rate of

heating

4. The oil is heated slowly when temperature of oil rises; it is checked for the flash point

for every one-degree rise in temperature.

AABBEELL’’SS FFLLAASSHH AANNDD FFIIRREE PPOOIINNTT TTEESSTT

5. After determining the flash point, the heating shall be further continued. The

temperature at which time of flame application that causes burning for a period at

least 5 seconds shall be recorded as the fire point.

6. Repeat the experiment 2 or 3 times with fresh sample of the same oil

7. Take the average value of flash and fire points.

PRECAUTIONS:

1. Stir the oil bath continuously to maintain the uniform temperature of sample oil.

2. The bluish halo that some time surrounds the test flame should not be

confused with true flash. OBSERVATIONS:

Sample oil Flash Point, 0 C Fire Point, 0 C

RESULT

The flash point is observed at _____ 0 C

The fire point is observed at ______ 0 C

AIM

To determine the flash and fire point of the given sample of oil using Pensky

Marten’s apparatus by both open and closed cup methods. APPARATUS

o Pensky Marten’s apparatus,

o Thermometer (0-110oC). THEORY

This method determines the closed cup and open cup flash and fire points of

petroleum products and mixtures to ascertain whether they give off inflammable vapours

below a certain temperature. Flash Point: It is the lowest temperatures of the oil at which application of test flame

causes the vapour above the sample to ignite with a distinct flash inside the cup.

Fire point It is the lowest temperature of the oil, at which, application of test flame causes

burning for a period of about five seconds.

DESCRIPTION

The apparatus consists of a brass cup and cover fitted with shutter mechanism

without shutter mechanism (open cup), test flame arrangement, hand stirrer (closed cup),

thermometer socket, etc., heated with energy regulator, a thermometer socket made of

copper. PROCEDURE

1. Clean the oil cup thoroughly and fill the oil cup with the sample oil to be tested up to

the mark.

2. Insert the thermometer into the oil cup through a provision, which measures the rise

of oil temperature.

3. Using the Energy regulator, control the power supply given to the heater and rate of

heating

4. The oil is heated slowly when temperature of oil rises, it is checked for the flash point

for every one degree rise in temperature.

PPEENNSSKKYY MMAARRTTEENN’’SS FFLLAASSHH AANNDD FFIIRREE PPOOIINNTT

5. After determining the flash point, the heating shall be further continued. The

temperature at which time of flame application which causes burning for a period at

least 5 seconds shall be recorded as the fire point.

6. Repeat the experiment 2 or 3 times with fresh sample of the same oil

7. Take the average value of flash and fire points.

PRECAUTIONS

1. Stir the oil bath continuously to maintain the uniform temperature of sample oil.

2. The bluish halo that some time surrounds the test flame should not be confused with

true flash.

OBSERVATIONS

Sample oil Flash Point, 0 C Fire Point, 0 C

RESULT

The flash point is observed at _________ 0 C

The fire point is observed at _____________ 0 C

AIM

To determine the water equivalent of the calorimeter using the given sample of solid

or liquid fuel of known calorific value (or) To determine the calorific value of the given solid

or liquid fuel if the water equivalent of the calorimeter known.

APPARATUS

Bomb, water jacket, stirrer, calorimeter vessel, combined lid, sensitive thermometer,

analytical balance with weight box, oxygen cylinder with pressure gauge, fuse wire, cotton

thread, firing unit, regulating valve and crucible hand pellet press

PRINCIPLE OF OPERATION

A Bomb Calorimeter will measure the amount of heat generated when matter is

burnt in a sealed chamber (Bomb) in an atmosphere of pure oxygen gas. A known amount

of the sample of fuel is burnt in the sealed bomb, the air in the bomb being replaced by

pure oxygen under pressure. The sample is ignited electrically. As the sample burns heat is

produced and rises in the temperature. Since the amount of heat produced by burning the

sample must be equal to the amount of heat absorbed by the calorimeter assembly, and

rise in temperature enables the determination of heat of the combustion of the sample. If

W = Water equivalent of the calorimeter assembly in calories per degree centigrade. T

= Rise in temperature (registered by a sensitive thermometer) in

degrees centigrade.

H = Heat of combustion of material in calories per gram. M

= Mass of sample burnt in grams.

Then W T H M

If the water equivalent of the calorimeter is to be determined, a substance like Benzoic acid

has a stable calorific value can be burnt in the bomb. Assuming the calorific value of

Benzoic acid and water equivalent can be determined.

BBOOMMBB CCAALLOORRIIMMEETTEERR

CALORIFIC VALUE

Gross or higher calorific value: The total amount of heat produced when one unit

mass of fuel has been burnt completely and the products of combustion have been cooled

to room temperature.

Net or Lower Calorific Value: The net heat produced when unit mass of fuel is burnt

completely and the products are permitted to escape.

LCV = HCV – Latent heat of water vapour formed DESCRIPTION

i. BOMB

The bomb consists of three parts i.e. bomb body, lid and the cap. Bomb Body

and the lid are made of corrosion resistant stainless steel containing Chromium,

Nickel and Molybdenum. The bomb body is cylindrical vessel having a capacity

of 300 ml. The walls are strong enough to withstand the normal operating

pressure (30atm) to extreme high pressures (300 atm.). During burning at high

pressure the nitrogen and sulphur contents are oxidized to nitric acid and

sulphuric acid respectively. The corrosion resistant nature of the bomb material

protects it from corrosive vapors. The bomb has lid, which is provided with two

terminals. The metallic rods pass through the terminals one of which are

provided with a ring for placing the crucible with a small hook and the other with a

groove. Each rod is also provided with a ring to press the fuse wire attached to it.

The upper side of the lid also provided with a small hook rod lifting and with a

Schrader valve for filling oxygen in the bomb

ii. WATER JACKET

The water jacket is made of copper and is highly chromium plated on the inside

and outside to minimize radiative losses. The jacket is filled with water.

iii. STIRRER UNIT

A stirrer is provided which is driven directly by an electric motor. The stirrer is

immersed in the water. The water is continuously stirred during the experiment

for uniform heat distribution.

iv. COMBINED LID

This is made of Borolite sheet and is provided with a hole for to keep the stirrer

unit in fixed position and hole to insert the temperature sensor. It has also

another hole to take out the connecting wires from the terminals on the bomb lid

to firing unit.

v. HAND PELLET PRESS

It is used for pressing the powder into a pellet.

vi. CRUCIBLE

It is made of stainless steel. The fuel to be burnt is weighed in this crucible.

vii. IGNITION WIRE

It is recommended that platinum wire used but an alternative nichrome wire is

also being offered.

viii. FIRING UNIT

It consists of the firing key, provision to give power to the stirrer motor, a switch

for operating the stirrer motor, two indicating lamps. When the circuit is

completed the indicating lamp glows. After the firing key is closed on, the fuse

wire burns, the indicating lamp stops glowing indicating the burning of the fuse

wire. PROCEDURE

About 0.5 to 1 grm of finely ground benzoic acid (Preferably compressed into a

pellet) is accurately weighed and taken into crucible.

Place the bomb lid on the stand provided and stretch pieces of fuse wire across

the electrodes (metal rods) provided in the lid tie about 5 cm of sewing cotton round

the wire.

Place the crucible in position and arrange the loose end of the cotton thread to

contact the Benzoic acid pellet in the crucible.

About 10 ml of distilled water are introduced into the bomb to absorb vapors of

sulphuric acid and nitric acids formed during the combustion and lid of the bomb is

screwed

Charge the bomb slowly with oxygen from the oxygen cylinder to a pressure of 25

atm. close the value and detach the bomb from the oxygen supply.

Fill the calorimeter vessel with sufficient water to submerge the cap of the bomb to a

depth of at least 2mm leaving the terminals projecting lower the bomb carefully in

the calorimeter vessel and after ascertaining that it is gas tight, connect the

terminals to the ignition circuit.

Adjust the stirrer and place the temperature sensor and cover in position. Start the

stirring mechanism, which must be kept in continuous operation during the

experiment after stirring for 5 minutes note the temperature reading of the

calorimeter. Close the circuit momentarily to fire the charge and continue the

observations of the temperature at an interval of one minute till the rate of change of

temperature becomes constant.

Afterwards stop the stirrer and remove the power supply to the firing unit. Remove

the bomb from the calorimeter and relax the pressure by opening the value. Verify

that the combustion is complete and washout the contents of the bomb clean and

dry.

Calculate the calorific value of the fuel or water equivalent of the calorimeter.

OBSERVATIONS:

Weight of the empty crucible W1 = gm

Weight of the empty crucible + Benzoic acid pellet W2 = gm

Weight of the benzoic acid pellet W2 W1 = gm

Weight of water taken in the calorimeter W3 = gm

Temperature of the water just before firing t1 = 0 C

Temperature of the water after firing t3 = 0 C

CALCULATIONS

Heat produced by burning of benzoic acid + Heat produced by burning of fuse wire

and cotton wire etc = Heat absorbed by calorimeter.

W2 W1 Cv W3 We t2 t1

PRECAUTIONS

Sample should not exceed 1 gms .

Don’t charge with more oxygen than is necessary.

Don’t fire the bomb if gas bubbles are leaking from the bomb when it is submerged in

water.

RESULT

Water equivalent of calorimeter We = gm

Calorific value of sample Cv = Cal/ gm

RESULT

Water equivalent of calorimeter We = gm

Calorific value of sample Cv = Cal/gm

AIM

To find the calorific value of given gaseous fuel. APPARATUS i) Calorimeter

a) Main calorimeter body

b) Three thermometers ii) Gas flow meter

a) Main gas flow meter body

b) Inlet / outlet nozzles

c) Union net with washer for thermometers iii) Pressure governor

a) Pressure governor body

b) Balancing beam arrangement

c) Counter balance tube

d) Inlet and outlet union nuts with washers and iv) Jars 2000 ml & 50 ml

PROCEDURE 1. Pour water into the governor till water starts overflowing through the overflow passage. 2. Replace and tighten the over flow nut. 3. Insert three thermometers provided with calorimeter into the rubber corks. 4. Insert rubber corks with thermometers into their places in calorimeter. 5. Insert burner into its support rod in the bottom of the calorimeter and turn the knurled

knob so that the burner is fixed tightly. The burner must go into the center of the

calorimeter body. 6. Connect the calorimeter, the flow meter and the pressure governor as shown in figure

using rubber tubing provided. Do not connect gas supply line. Take care to see that the

water regulator of calorimeter is in OFF position.

JJUUNNKKEERR’’SS GGAASS CCAALLOORRIIMMEETTEERR

7. Turn water regulator knob on calorimeter to ON position. Allow water to flow through the

calorimeter from overhead tank/ tap. Allow water to flow for 3 to 4 min into laboratory

sink, through the calorimeter. 8. Ensure that outlet tap of governor is closed. Connect gas supply line to governor inlet.

Remove burner from calorimeter then open governor outlet tap. Allow gas to pass

through the burner. 9. Light up the burner by holding a lighted match stick near the mesh at the top. 10. Adjust the air regulator sleeve at the bottom of the burner to get a blue, non-luminous

flame. Fix the lighted burner back into position. 11. Adjust water regulator on calorimeter to get a temperature difference of 12 0 C to

15 0 C between the inlet water & outlet water as indicated by the respective

Thermometers at the top of the calorimeter. 12. Allow 20 to 30 min for outlet water temperature to become steady. 13. Measure the water flow rate with the help of measuring jar. Simultaneously, note the

flow meter reading.

14. Note down the inlet &outlet water temperatures. 15. Repeat the test with same volume of gas 3 or 4 times and take average temperatures of

inlet and outlet water. CALCULATIONS

The formula to be used to calculate the calorific value to the test gas is as follows

C V = VW

x (T2-T1)x1000 VG

Where

C.V = calorific value of gas in Kcal

m3

VG = volume of gas in liters consume during test period

Vw = volume of water in liters passed during test period

VVAALLVVEE TTIIMMIINNGG DDIIAAGGRRAAMM

VALVE TIMING DIAGRAM ON SECTIONAL MODEL OF 4-STROKE SINGLE CYLINDER

DIESEL ENGINE

AIM:-To draw the actual valve timing diagram of a four-stroke single cylinder vertical diesel

engine.

APPARATUS:-Thread, scale, sectional four stroke single cylinder diesel engine test rig.

THEORY:-

Valve timing is the regulation of the points in the cycle at which the valves are set to

open and close. While the intake and exhaust valves should open, theoretically, at dead

centers, almost all SI engines employ an intake and exhaust valves opening and closing

a few degrees before dead centers .There are two factors: Mechanical and Dynamic for

the actual valve timing to be different from the theoretical valve timing.

a) Mechanical factor:-

The valves of a reciprocating engine are operated by cam mechanism. To avoid noise

and wear, the valve should be lifted slowly. For the same reason the valve cannot be

closed abruptly else it will bounce on its seat. Then the opening and closing periods are

spread over a considerable number of crank shaft degrees. As a result the opening of

the valve must commence a head of time at which it is fully opened. The same reason

applied for the closing time and valve must close after dead centers.

b) Dynamic factor:-

Besides the mechanical factor the actual valve timing is set taking the dynamic effects

of gas flow into consideration. As the piston moves all in the suction stroke, the fresh

air is drawn into the cylinder through the inlet valve when the piston reaches the BDC

and to move towards TDC in the compression stroke, the inertia of the entering fresh air

tends to cause to continue to move in the cylinder after BDC.

The exhaust valve is set to open before BDC. By earlier opening of the exhaust valve,

the scavenging period is increased. Also earlier opening means that exhaust pressure

is higher than the atmospheric pressure, which helps in scavenging process. The

exhaust valve is closed a few degrees after TDC. The inertia of the exhaust gases

tends to scavenge the cylinder by carrying out a greater mass gas lift in Clearance

volume. For some period there is valve overlapping i.e., the kinetic energy of fresh

charge helps in forcing out at exhaust gases.

WORKING PRINCIPLE:-

In a four stroke engine, the thermodynamic cycle of operations is completed in two

revolutions of the crank shaft or four strokes of the piston. During the four strokes, there are

five events to be completed, viz., suction, compression, combustion, expansion and

exhaust.

Suction stroke starts when the piston is at TDC and about to move downwards. The

inlet valve is open at this time and exhaust valve is closed. Due to the suction created by

the motion of the piston towards the BDC, air is drawn into the cylinder. When the piston

reaches the BDC the suction stroke ends and the inlet valve closes.

The air taken into the cylinder during the suction stroke is compressed by the return

stroke of the piston. During this stroke both inlet and exhaust valves are in closed position.

The air is now compressed to the clearance volume. At the end of the compression stroke

a metered quantity of fuel (diesel) is injected into the hot compressed air in fine sprays by

the fuel injector and it starts burning. During burning process the chemical energy of the

fuel is converted into heat energy.

The high pressure of the burnt gases forces the piston towards the BDC. Both the

valves are in closed position. Of the four-strokes only during this stroke, power is produced.

Both pressure and temperature decreases during expansion.

At the end of the expansion stroke the exhaust valve opens and the inlet valve remains

closed. The pressure falls to atmospheric level as a part of the burnt gases escape. The

piston starts moving from BDC to TDC and sweeps the burnt gases out from the cylinder.

The exhaust valve closes when the piston reaches TDC.

PROCEDURE:-

1. T.D.C. is identified and marked on the fly wheel with respect to one fixed point in the

engine.

2. The circumference of fly wheel is measured using thread and scale.

3. The BDC is marked on the flywheel by taking half the circumference.

4. By slowly cranking the camshaft in the direction of rotation the opening of inlet valve

is marked on the fly wheel w.r.t. fixed point when the push rod of inlet valve

becomes tight to move.

5. Mark a point on the fly wheel where the inlet valve is completely closed.

6. In the same way mark the points where the exhaust valve open and close.

7. The distance of opening of inlet valve and closing of exhaust valve from TDC and

closing of inlet valve and opening of the exhaust valve from BDC are measured

using thread and scale.

8. The angles of opening and closing of inlet and exhaust valves are calculated w.r.t.

TDC and BDC.

PRECAUTIONS:-

1. The decompression lever must be checked (Should be in disengaged position) when

conducting the test.

2. Cranking should be done carefully and slowly so that the salient points are located

carefully.

OBSERVATIONS: circumference of the fly wheel = 2R

Sl.No. Event Distance from nearest dead

center Angle

1 IVO

2 IVC

3 EVO

4 EVC

5 FI

IVO = Inlet valve open

IVC = Inlet valve close

EVO = Exhaust valve open

EVC = Exhaust valve close

FI = Fuel Injection

1 cm = (1 rev of fly wheel / circumference of fly wheel) 0

X cm = X * (360/ π D) 0

Where D= diameter of the fly wheel in cm

Model Calculations:

1. Inlet valve opens at ……. cm before TDC =….. X 30 = …..0

2. Inlet valve closes at …….

3. Exhaust valve opens at

4. Exhaust valve closes at

5. Total suction process = IVO to IVC =

6. Total compression = BDC to TDC =

7. Total expansion = TDC to EVO =

8. Total exhaust = EVO to EVC =

RESULT:-

1. Total suction process :

2. Total compression process :

3. Total expansion process :

4. Total exhaust process :

5. Fuel Injection at :

PPOORRTT TTIIMMIINNGG DDIIAAGGRRAAMM

PORT TIMING DIAGRAM ON SECTIONAL MODEL OF 2-STROKE SINGLE CYLINDER

PETROL ENGINE

AIM: To draw the actual port timing diagram of a two stroke single cylinder petrol engine.

APPARATUS: Thread, scale, sectional single cylinder two stroke petrol engine test rig.

THEORY:

Port timing is the determination of points in the cycle at which the ports are set to open

and close. In the ideal cycle inlet, exhaust and transfer port opens and closes at dead

centers, but there is a difference between actual and ideal cycle.

WORKING PRINCIPLE:-

In two-stroke engine the cycle is completed in one revolution of the

crankshaft. The main difference between two-stroke and four stroke engines is in the

method of filling the fresh charge and removing the burnt gases from the cylinder. In the

four-stroke engine these operations are performed by the engine piston during the suction

and exhaust strokes respectively. In a two-stroke engine, the filling process is

accomplished by the charge compressed in crankcase or by a blower. The induction of the

compressed charge moves out of the product of combustion through exhaust ports.

Therefore, no piston strokes are required for these two operations. Two strokes are

sufficient to complete the cycle, one for compressing the fresh charge and the other for

expansion or power stroke.

The air or charge is inducted into the crankcase through the spring loaded

inlet port when the pressure in the crankcase is reduced due to the upward motion of the

piston during compression stroke. After compression and ignition, expansion takes place in

the usual way.

During the expansion stroke the charge in the crankcase is compressed. Near

the end of the expansion stroke, the piston uncovers the exhaust ports and the cyl inder

pressure drops to atmospheric pressure as the combustion products leave the cylinder.

Further movement of the piston uncovers the transfer port, permitting the slightly

compressed charge in the crankcase to enter the engine cylinder.

PROCEDURE:

1. The circumference of the flywheel is measured using thread and scale.

2. T.D.C. is identified and marked on the flywheel with respect to one fixed point in the

engine.

3. The B.D.C. is measured on the fly wheel by taking half of the circumference.

4. Mark various points on the flywheel relative to the opening and closing of ports.

OBSERVATIONS:-

S.NO Event Distance From Nearest

dead center Crank angle

1. IPO

2. IPC

3. TPO

4. TPC

5. EPO

6. EPC

I.P.O = Inlet port open

I.P.C = Inlet port close

T.P.O = Transfer port open

T.P.C = Transfer port close

E.P.O = Exhaust port open

E.P.C = Exhaust port close

1 cm = (1 rev of fly wheel / circumference of fly wheel) 0

X cm = X * (360/ ∏ D) 0

Model Calculations:

1. Transfer port opens at ….. cm before BDC = …… 0 before BDC.

2. Transfer port closes at

3. Exhaust port opens at

4. Exhaust port closes at

5. Spark ignition is produced at

RESULT:-

1. Total suction process:

2. Total compression process:

3. Total expansion process:

4. Total exhaust process

PPEERRFFOORRMMAANNCCEE TTEESSTT OONN TTWWOO SSTTAAGGEE RREECCIIPPRROOCCAATTIINNGG

AAIIRR CCOOMMPPRREESSSSOORR

PERFORMANCE TEST ON TWO STAGE RECIPROCATING AIR COMPRESSOR

AIM:

To conduct performance test on reciprocating air compressor, to determine its volumetric

efficiency and Isothermal efficiency.

EQUIPMENT /APPARATUS:

1. Two stage air compressor

2. Tachometer 0-2000 rpm

3. Stop watch

SPECIFICATIONS: Make : Altech

Dia. of low pressure piston : 70 mm

Dia. of High Pressure Piston : 50 mm

Stroke : 90 mm

Operating Pressure : 8 kgf / cm2

Speed : 700 rpm

Diameter of orifice : 20 mm

Power : 3 HP

Energy Meter Constant : 300 rev/kwh

DESCRIPTION:

The air compressor is a two stage, reciprocating type. The air is sucked from

atmosphere and compressed in the first cylinder. The compressed air then passes through

an inter cooler into the second stage cylinder, the compressed air then goes to reservoir

through safety valve. This valve operates an electrical switch that shuts off the motor when

pressure exceeds the set limit.

The test consists of an air chamber containing an orifice plate and a u-tube

manometer, the compressor and an induction motor.

PROCEDURE:

1) Open the discharge valve of the compressor and drain off air completely and

Close the valve.

2) Start the compressor, by starting the compressor motor & observe the pressure

developing slowly

3) At the particular test pressure, the outlet valve is opened slowly and adjusted so

that the pressure in the tank maintained constant.

4) At the particular test pressure, note the following reading

(i) Manometer,

(ii) Speed of the compressor,

(iii) Pressure,

(Iv) Time taken for 10 revolutions of energy meter.

5) Close the discharge valve so that pressure increases.

6) Repeat the above procedure for different pressures.

7) Switch off the power supply and stop the compressor.

PRECAUTIONS:

1. Check oil level in the compressor crank case

2. The orifice should never be closed

3. At the end of the experiment the outlet valve at of the reservoir should be opened as

the compressor is to be started again at low pressure to prevent undue strain on the

piston.

OBSERVATIONS:

S.No. Gauge

Pressure (kgf/cm2)

manometer readings in m

of water

Air head causing

flow in m of water

Speed

Actual Volume

Va

m3 / Sec

Theoretical Volume,

Vt

m3 / Sec

vol

% h1 h2 hw

1.

2.

3.

4.

5.

`

S.No.

Gauge Pressure (kgf/cm2)

Time for ‘n’ no: of

revolutions of Energy meter ‘s’

Motor input=

tk

n

3600

KW

Motor output=

8.0

motorinput

KW

Compressor input=

95.08.0

motorinput

KW

Compressor output=

ClnVP aa

KW

iso

%

1.

2.

3.

4.

5.

CALCULATIONS:

1. Actual Air intake:

Manometer reading h1 = …………..mm of water

Manometer reading h2 = …………..mm of water

Difference in water level, hw = 1000

21 hh m of water

Equivalent air column, ha = 16.1

1000

ww h

AirofDensity

waterofDensityh ….m. of air

Where hw = m. of water column

ha =m. of air column

w =Density of water in kg/m3 (1000 kg/m3)

a =Density of air in kg/m3 (1.16 kg/m3)

2. The actual volume of air compressed, Va = Cd a agh2 …..m3 / Sec

Where Cd=co efficient of discharge for the orifice =0.62

Orifice diameter = 0.02 m

Area of orifice, a = 4

)02.0( 2 = …..m2

ha= equivalent air column in ‘m’ of water

3. Theoretical volume of air compressed, Vt = 60

NLD4

2

…..m3 / Sec

Diameter of piston, D = 0.07 m

Stroke length, L = 0.09 m

Speed of the compressor, N = ……..rpm

4. Volumetric efficiency = 100V

V

t

a

5. Compressor input = Motor input 95.08.0 …..KW

Where

Energy meter constant, K= 300 Rev/KWh

Time for ‘n’ number of rev. = t sec

Motor input = tK

n

3600…….. KW

Efficiency of motor = 80%

Output of motor = Motor input 8.0

Belt transmission efficiency = 95 %( assumed)

Compressor input = Motor input 95.08.0 …..KW

6. Compressor output = ClnVP aa …….Kw

Compression ratio, C = pressure Atm.

pressure Atm. pressure Gauge

= 1.01325

1.01325 pressure Gauge

Note: Gauge pressure in Kgf/cm2

Pa= Atmospheric pressure = 101.325 KPa

Va= Actual volume of air compressed m3/sec

7. Isothermal efficiency = 100input Compressor

output Compressor

Model Graphs: Pressure Pressure Result:

Volu

met

ric

Eff

icie

ncy

Isoth

erm

al

Eff

icie

ncy

PPEERRFFOORRMMAANNCCEE TTEESSTT OONN 44--SSTTRROOKKEE,,

SSIINNGGLLEE CCYYLLIINNDDEERR DDIIEESSEELL EENNGGIINNEE

PPEERRFFOORRMMAANNCCEE TTEESSTT OONN 44--SSTTRROOKKEE SSIINNGGLLEE CCYYLLIINNDDEERR DDIIEESSEELL EENNGGIINNEE

AAIIMM:: TToo ccoonndduucctt aa ppeerrffoorrmmaannccee tteesstt oonn 44--ssttrrookkee ssiinnggllee ccyylliinnddeerr ddiieesseell eennggiinnee

uunnddeerr vvaarriioouuss llooaaddss..

EEQQUUIIPPMMEENNTT//AAPPPPAARRAATTUUSS::

11.. 44--SSttrrookkee,, ssiinnggllee ccyylliinnddeerr DDiieesseell eennggiinnee wwiitthh aa rrooppee bbrraakkee ddyynnaammoommeetteerr TTeesstt rriigg

22.. SSttooppwwaattcchh..

SSPPEECCIIFFIICCAATTIIOONNSS::

MMaakkee :: KKiirrlloosskkaarr

BBoorree :: 8800mmmm

SSttrrookkee :: 111100 mmmm

RRaatteedd SSppeeeedd :: 11550000 rrppmm

MMaaxx.. BB..PP :: 33..77KKWW ((55 HH..PP))

CCoommpprreessssiioonn RRaattiioo :: 1166..55::11

OOrriiffiiccee DDiiaammeetteerr :: 2200 mmmm

FFuueell :: DDiieesseell

DDeennssiittyy ooff DDiieesseell :: 882277 KKgg//mm33

SSppeecciiffiicc ggrraavviittyy ooff DDiieesseell :: 00..882277

CCaalloorriiffiicc VVaalluuee ooff DDiieesseell :: 4433440000 KKJJ // kkgg

BBrraakkee ddrruumm ddiiaammeetteerr :: 336600 mmmm

RRooppee ddiiaammeetteerr :: 1155 mmmm

EEqquuiivvaalleenntt ddiiaammeetteerr :: 337755 mmmm

CCooeeffffiicciieenntt ooff ddiisscchhaarrggee :: 00..6622

DDEESSCCRRIIPPTTIIOONN::

This is a water cooled single cylinder vertical diesel engine. It is coupled to a rope

pulley brake arrangement to absorb the power produced. Necessary weights and spring

balances are included to apply load on the brake drum. Suitable cooling water arrangement

for the brake drum is provided. Separate cooling water lines are provided for the engine

cooling. Thermocouples are provided for measuring temperature. A fuel measuring system

consists of a fuel tank mounted on a stand, burette, and a 3-way cork.

Air consumption is measured by using a M.S. tank, which is fitted with a standard

orifice and a U-tube water manometer that measures the pressures inside the tank..

TTHHEEOORRYY::

SSiinnggllee ccyylliinnddeerr ssttaattiioonnaarryy,, ccoonnssttaanntt ssppeeeedd ddiieesseell eennggiinneess aarree ggeenneerraallllyy qquuaalliittyy

ggoovveerrnneedd.. AAss ssuucchh tthhee aaiirr ssuupppplliieedd ttoo tthhee eennggiinnee iiss nnoott tthhrroottttlleedd aass iinn tthhee ccaassee ooff SS..II..

eennggiinneess.. TToo mmeeeett tthhee ppoowweerr rreeqquuiirreemmeennttss ooff tthhee sshhaafftt,, tthhee qquuaannttiittyy ooff ffuueell iinnjjeecctteedd iinnttoo tthhee

ccyylliinnddeerr iiss vvaarriieedd bbyy tthhee rraacckk iinn tthhee ffuueell ppuummpp.. TThhee rraacckk iiss uussuuaallllyy ccoonnttrroolllleedd bbyy aa ggoovveerrnnoorr

oorr bbyy aa hhaanndd.. TThhee aaiirr ffllooww rraattee ooff ssiinnggllee ccyylliinnddeerr eennggiinnee ooppeerraattiinngg aatt ccoonnssttaanntt ssppeeeedd ddooeess

nnoott vvaarryy aapppprreecciiaabbllyy wwiitthh tthhee oouuttppuutt ooff tthhee eennggiinnee.. SSiinnccee tthhee ffuueell ffllooww rraattee vvaarriieess mmoorree oorr

lleessss lliinneeaarrllyy wwiitthh oouuttppuutt,, tthhee ffuueell aaiirr rraattiioo iinnccrreeaasseess wwiitthh oouuttppuutt.. PPeerrffoorrmmaannccee tteessttss ccaann bbee

ccoonndduucctteedd eeiitthheerr aatt ccoonnssttaanntt ssppeeeedd ((oorr)) aatt ccoonnssttaanntt tthhrroottttllee.. TThhee ccoonnssttaanntt ssppeeeedd mmeetthhoodd

yyiieellddss tthhee FF..PP.. ooff tthhee eennggiinnee..

TThhee eennggiinnee ppeerrffoorrmmaannccee iiss iinnddiiccaatteedd bbyy tthhee tteerrmm ““eeffffiicciieennccyy””.. FFiivvee iimmppoorrttaanntt

eennggiinnee eeffffiicciieenncciieess aanndd ootthheerr rreellaatteedd eennggiinnee ppeerrffoorrmmaannccee ppaarraammeetteerrss aarree::

11.. IInnddiiccaatteedd tthheerrmmaall eeffffiicciieennccyy 22..BBrraakkee tthheerrmmaall eeffffiicciieennccyy

33.. MMeecchhaanniiccaall eeffffiicciieennccyy 44..VVoolluummeettrriicc eeffffiicciieennccyy

55.. RReellaattiivvee eeffffiicciieennccyy 66..MMeeaann eeffffeeccttiivvee pprreessssuurree

77.. SSppeecciiffiicc ppoowweerr oouuttppuutt 88..SSppeecciiffiicc ffuueell ccoonnssuummppttiioonn

99.. FFuueell--aaiirr rraattiioo 1100..CCaalloorriiffiicc vvaalluuee ooff tthhee ffuueell

SSTTAARRTTIINNGG TTHHEE EENNGGIINNEE::

11.. EEnnggaaggee ddee--ccoommpprreessssiioonn lleevveerr bbeeffoorree ccrraannkkiinngg..

22.. CCrraannkk tthhee eennggiinnee aanndd ddiisseennggaaggee tthhee ddee--ccoommpprreessssiioonn lleevveerr..

33.. AAddjjuusstt tthhee ggoovveerrnnoorr ttoo aattttaaiinn tthhee rraatteedd ssppeeeedd..

PPRROOCCEEDDUURREE::

11.. OOppeenn tthhee tthhrreeee wwaayy ccoorrkk ssoo tthhaatt ffuueell fflloowwss ttoo tthhee eennggiinnee ddiirreeccttllyy ffrroomm tthhee ttaannkk..

22.. OOppeenn tthhee ccoooolliinngg wwaatteerr vvaallvveess aanndd eennssuurree wwaatteerr fflloowwss tthhrroouugghh tthhee eennggiinnee..

33.. SSttaarrtt tthhee eennggiinnee aanndd aallllooww rruunnnniinngg oonn nnoo llooaadd ccoonnddiittiioonn ffoorr ffeeww mmiinnuutteess..

44.. LLooaadd eennggiinnee bbyy aaddddiinngg wweeiigghhttss uuppoonn tthhee hhaannggeerr..

55.. AAllllooww tthhee ccoooolliinngg wwaatteerr iinn tthhee bbrraakkee ddrruumm aanndd aaddjjuusstt iitt ttoo aavvooiidd ssppiilllliinngg..

66.. AAllllooww tthhee eennggiinnee ttoo rruunn aatt tthhiiss llooaadd ffoorr ffeeww mmiinnuutteess..

77.. NNoottee tthhee ffoolllloowwiinngg rreeaaddiinnggss

aa)) EEnnggiinnee ssppeeeedd..

bb)) WWeeiigghhtt oonn tthhee hhaannggeerr..

cc)) SSpprriinngg bbaallaannccee

dd)) MMaannoommeetteerr

ee)) TTiimmee ffoorr 1100 cccc ooff ffuueell ccoonnssuummppttiioonn

88.. RReeppeeaatt tthhee aabboovvee pprroocceedduurree aatt ddiiffffeerreenntt llooaaddss..

99.. SSttoopp tthhee eennggiinnee aafftteerr rreemmoovviinngg llooaadd oonn tthhee eennggiinnee..

PPRREECCAAUUTTIIOONNSS::

11.. BBeeffoorree ssttaattiinngg tthhee eennggiinnee cchheecckk aallll tthhee ssyysstteemmss ssuucchh aass ccoooolliinngg,, lluubbrriiccaattiioonn aanndd ffuueell

ssyysstteemm

22.. EEnnssuurree ooiill lleevveell iiss mmaaiinnttaaiinneedd iinn tthhee eennggiinnee uupp ttoo rreeccoommmmeennddeedd lleevveell aallwwaayyss.. NNeevveerr

rruunn tthhee eennggiinnee wwiitthh iinnssuuffffiicciieenntt ooiill..

33.. NNeevveerr rruunn tthhee eennggiinnee wwiitthh iinnssuuffffiicciieenntt eennggiinnee ccoooolliinngg wwaatteerr aanndd eexxhhaauusstt ggaass

ccaalloorriimmeetteerr ccoooolliinngg wwaatteerr..

44.. FFoorr ssttooppppiinngg tthhee eennggiinnee,, llooaadd oonn tthhee eennggiinnee sshhoouulldd bbee rreemmoovveedd..

GRAPHS

11.. TT..FF..CC VVss BB ..PP 44.. II tthh VVss BB ..PP

22.. SS..FF..CC VVss BB ..PP 55.. mm VVss BB ..PP

33.. BBtthh VVss BB ..PP

OOBBSSEERRVVAATTIIOONNSS::

SS..NN

OO

LLooaadd

oonn

tthh

ee

bbrr aakk

ee dd

rr uu

mm

SSpp

ee ee dd

MMaann

oomm

ee tt ee

rr

rr ee aa

ddii nn

gg

AAii rr

hhee aadd

ccaauu

ss iinn

gg ff

ll ooww

(( HHaa))

mm oo

ff aaii rr

TTii mm

ee ff

oorr 11

00 cc

cc

ooff

ff uuee ll

TT.. FF

.. CC

HHee aatt

II nnpp

uutt

BB.. PP

FF.. PP

II ..PP

hh11 hh22 hh11~~hh22 WW11

kkgg SS

kkgg WW

kkgg

RRPP

MM

SSeecc kkgg//hhrr kkWW kkWW kkWW kkWW

11

22

33

44

55

66

SSAAMMPPLLEE CCAALLCCUULLAATTIIOONNSS::

11.. MMaannoommeetteerr RReeaaddiinngg hh11== mmmm

hh22 == mmmm

hh11~~hh22 ==hh== ……………………..mmmm ooff aaiirr

22.. AAiirr hheeaadd ccaauussiinngg ffllooww:: HHaa ==1000

h

air

water

== …….. mm ooff wwaatteerr

33.. EEnnggiinnee oouuttppuutt ((BBrraakkee PPoowweerr)) [[BB..PP]] == 100060

NT2

………… KKWW

WWhheerree,,

NN == RRaatteedd ssppeeeedd …….... RRppmm,,

WW11 == WWeeiigghhtt oonn hhaannggeerr ……………….. kkgg

SS == sspprriinngg bbaallaannccee rreeaaddiinngg ………………..kkgg

RRee == EEffffeeccttiivvee bbrraakkee ddrruumm rraaddiiuuss == ((RR ++ rr)) …… mm

WWhheerree RR iiss BBrraakkee ddrruumm rraaddiiuuss

rr iiss RRooppee rraaddiiuuss

WW == NNeett LLooaadd == ((WW11--SS)) 99..8811 ……………… NN

TT == TToorrqquuee == ((WW ** RRee))……………………NN--mm

TTiimmee ffoorr 1100cccc ooff ffuueell ccoonnssuummppttiioonn,, tt == ………….. SSeecc,,

S.NO

II..SS..FF..CC BB..SS..FF..CC

AAccttuuaall

vvoolluummee

ooff aaiirr VVaa MMaassss ooff aaiirr

TThheeoorreettiiccaall

vvoolluummee ooff aaiirr

VVtthh EEffffiicciieenncciieess

kkgg//kkww--hh kkgg//kkww--hh mm33//ss kkgg//ss

mm33//ss vv BB tthh II tthh mm

11

22

33

44

55

66

MMaassss ooff ffuueell ccoonnssuummppttiioonn ppeerr sseecc,, mmff == 1000

.10 dieselofGravitySp

t kkgg//sseecc

44.. TToottaall FFuueell ccoonnssuummppttiioonn,, TTFFCC == …… mmff 33660000……..kkgg // hhrr..

55.. HHeeaatt IInnppuutt,, HHII == 6060

CVTFC …………..KKWW

WWhheerree CCVV iiss ccaalloorriiffiicc vvaalluuee ooff DDiieesseell == 4433440000 KKJJ // kkgg

66.. FF.. PP == FFrriiccttiioonnaall PPoowweerr ffrroomm WWiilllliiaamm’’ss lliinnee ddiiaaggrraamm..

((TTFFCC VVss BB..PP))

77.. IInnddiiccaatteedd PPoowweerr,, II..PP == BB..PP ++ FF..PP

88.. BBrraakkee ssppeecciiffiicc ffuueell ccoonnssuummppttiioonn,, BBSSFFCC == PB

CFT

.

..…………....KKgg //KKww--hhrr

99.. IInnddiiccaatteedd ssppeecciiffiicc ffuueell ccoonnssuummppttiioonn,, IISSFFCC ==PI

CFT

.

..…………KKgg //KKww--hhrr

1100.. AAccttuuaall vvoolluummee ooff aaiirr iinnttaakkee==VVaa== CCdd AA00 aHg 2 == …….. mm33

WWhheerree CCdd== 00..6622

AA00== 33..1144 XX 1100--44 mm22

1111.. MMaassss ooff aaiirr iinnttaakkee mmaa == air VVaa …….. KKgg..

1122.. TThheeoorreettiiccaall vvoolluummee ooff aaiirr == VVtthh == 602

N Ls D4

2

mm33//SSeecc

1133.. VVoolluummeettrriicc eeffffiicciieennccyy == 100Vth

Va %%

1144.. BBrraakkee tthheerrmmaall eeffffiicciieennccyy,, BB tthh == 100.

.

IH

PB

1155.. IInnddiiccaatteedd tthheerrmmaall eeffffiicciieennccyy,, II tthh == 100.

HI

PI

1166..

1177.. MMeecchhaanniiccaall eeffffiicciieennccyy,, mm == 100.

.

PI

PB

MMOODDEELL GGRRAAPPHHSS::

BB..PP ,, KKWW

SSFF

CC

KKgg

// KKWW

-- hhrr

BB

tthh,, %%

RESULT:-

BB..PP,, KKWW

mm

eecchh ,,%%

BB..PP,, KKWW

ii tthh,, %%

BB..PP,, KKWW

BB..PP,, KKWW FF.. PP,, KKWW

TTFF

CC,,

KKgg

// hh

rr

HEAT BALANCE SHEET PREPARATION ON 4-

STROKE, SINGLE CYLINDER DIESEL ENGINE

TEST RIG

HEAT BALANCE SHEET PREPARATION ON 4-STROKE, SINGLE CYLINDER

DDIIEESSEELL EENNGGIINNEE TTEESSTT RRIIGG

AAIIMM:: TToo ccoonndduucctt aa HHeeaatt BBaallaannccee TTeesstt oonn aa 44-- ssttrrookkee ssiinnggllee ccyylliinnddeerr vveerrttiiccaall ddiieesseell eennggiinnee

aatt ddiiffffeerreenntt llooaaddss aanndd ttoo ddrraaww uupp aa hheeaatt bbaallaannccee sshheeeett oonn mmiinnuuttee bbaassiiss..

EEQQUUIIPPMMEENNTT // AAPPPPAARRAATTUUSS::

11.. 44--SSttrrookkee SSiinnggllee ccyylliinnddeerr DDiieesseell eennggiinnee wwiitthh aa rrooppee bbrraakkee ddyynnaammoommeetteerr..

22.. TTaacchhoommeetteerr ((00--22000000 rrppmm..))


SSPPEECCIIFFIICCAATTIIOONNSS

MMaakkee :: KKiirrlloosskkaarr mmooddeell AAVVII

BBoorree :: 8800 mmmm



MMaaxx.. BB..PP :: 33..77 KKWW

CCoommpprreessssiioonn RRaattiioo :: 1166 ..55::11

OOrriiffiiccee ddiiaammeetteerr :: 2200 mmmm

FFuueell :: DDiieesseell



BBrraakkee ddrruumm ddiiaammeetteerr :: 336600 mmmm

RRooppee ddiiaammeetteerr :: 1155 mmmm

EEqquuiivvaalleenntt ddiiaammeetteerr :: 337755 mmmm


TThhiiss iiss aa wwaatteerr ccoooolleedd ffoouurr ssttrrookkee ssiinnggllee ccyylliinnddeerr vveerrttiiccaall ddiieesseell eennggiinnee iiss ccoouupplleedd ttoo

aa rrooppee ppuulllleeyy bbrraakkee aarrrraannggeemmeenntt ttoo aabbssoorrbb tthhee ppoowweerr pprroodduucceedd,, NNeecceessssaarryy wweeiigghhttss aanndd

sspprriinngg bbaallaanncceess aarree iinncclluuddeedd ttoo aappppllyy llooaadd oonn tthhee bbrraakkee ddrruumm.. SSuuiittaabbllee ccoooolliinngg wwaatteerr

aarrrraannggeemmeenntt ffoorr tthhee bbrraakkee ddrruumm iiss pprroovviiddeedd.. SSeeppaarraattee ccoooolliinngg wwaatteerr lliinneess aarree pprroovviiddeedd ffoorr

tthhee eennggiinnee ccoooolliinngg.. TThheerrmmooccoouupplleess aarree pprroovviiddeedd ffoorr mmeeaassuurriinngg tteemmppeerraattuurree.. AA ffuueell

mmeeaassuurriinngg ssyysstteemm ccoonnssiissttss ooff aa ffuueell ttaannkk mmoouunntteedd oonn aa ssttaanndd,, bbuurreettttee,, aanndd aa 33--wwaayy ccoorrkk..

AAiirr ccoonnssuummppttiioonn iiss mmeeaassuurreedd bbyy uussiinngg aa MM..SS.. ttaannkk,, wwhhiicchh iiss ffiitttteedd wwiitthh aa ssttaannddaarrdd oorriiffiiccee

aanndd aa UU--ttuubbee wwaatteerr mmaannoommeetteerr tthhaatt mmeeaassuurreess tthhee pprreessssuurreess iinnssiiddee tthhee ttaannkk..

TTeesstt RRiigg iiss pprroovviiddeedd wwiitthh eexxhhaauusstt ggaass ccaalloorriimmeetteerr.. TThhee eexxhhaauusstt ggaass ppiippee iiss

ccoonnnneecctteedd ttoo aa hheeaatt eexxcchhaannggeerr wwhheerreeiinn,,tthhee ggaasseess aarree ccoooolleedd bbyy aa ccoooolliinngg wwaatteerr lliinnee..

TThheerrmmooccoouupplleess aarree pprroovviiddeedd ttoo mmeeaassuurree tthhee iinnlleett aanndd oouuttlleett tteemmppeerraattuurreess ooff eexxhhaauusstt ggaass

aass wweellll aass ccoooolliinngg wwaatteerr ffoorr tthhee ccaalloorriimmeetteerr..

TTHHEEOORRYY::

PPaarrtt ooff tthhee hheeaatt ssuupppplliieedd ttoo aann II..CC.. eennggiinnee tthhrroouugghh tthhee ffuueell iiss uuttiilliizzeedd iinn ddooiinngg uusseeffuull

wwoorrkk,, aanndd tthhee rreesstt iiss wwaasstteedd iinn oovveerrccoommiinngg ffrriiccttiioonn,, iinn eexxhhaauusstt ggaasseess aanndd iinn eennggiinnee ccoooolliinngg

wwaatteerr.. AA ssttaatteemmeenntt ooff tthhee ssuupppplliieedd hheeaatt,, uusseeffuull wwoorrkk aanndd hheeaatt wwaasstteedd iinn oovveerrccoommiinngg

ffrriiccttiioonn,, eexxhhaauusstt ggaasseess,, eennggiinnee ccoooolliinngg iiss ccaalllleedd hheeaatt bbaallaannccee sshheeeett.. IItt mmaayy bbee ddrraawwnn oonn

tthhee bbaassiiss ooff uunniitt ttiimmee oorr ccyyccllee ooff ooppeerraattiioonn..

TThhee hheeaatt bbaallaannccee tthhuuss ggiivveess aa ppiiccttuurree aabboouutt tthhee uuttiilliittyy ooff hheeaatt ssuupppplliieedd tthhrroouugghh tthhee ffuueell..

TThhee lloosssseess ddeeppeennddss uupp oonn ttyyppee ooff tthhee eennggiinnee,, sseerrvviiccee ttoo wwhhiicchh iitt iiss eemmppllooyyeedd,, llooaadd,,

aattmmoosspphheerriicc ccoonnddiittiioonnss eettcc.. AA ddeessiiggnneerr iiss iinntteerreesstteedd ttoo kkeeeepp tthhee lloosssseess aass llooww aass ppoossssiibbllee

iinn oorrddeerr ttoo mmaaxxiimmiizzee tthhee rraatteedd ppoowweerr.. TTwwoo iimmppoorrttaanntt ffaaccttoorrss tthhaatt iinnfflluueennccee tthhee lloosssseess aarree

ssppeeeedd aanndd oouuttppuutt ooff aann eennggiinnee.. TThhee lloossss dduuee ttoo ffrriiccttiioonn iinnccrreeaasseess ccoonnssiiddeerraabbllyy mmoorree dduuee ttoo

iinnccrreeaassee iinn eennggiinnee ssppeeeedd tthhaann bbyy aann iinnccrreeaassee iinn llooaadd.. HHeeaatt ccaarrrriieedd aawwaayy bbyy eennggiinnee wwaatteerr

iinnccrreeaasseess sslloowwllyy wwiitthh llooaadd wwhhiillee hheeaatt ccaarrrriieedd aawwaayy bbyy eexxhhaauusstt ggaasseess iinnccrreeaasseess aabbrruuppttllyy

bbeeyyoonndd 8800%% ooff tthhee rraatteedd ppoowweerr oouuttppuutt dduuee ttoo hhiigghheerr ccoommbbuussttiioonn tteemmppeerraattuurreess,, iinneeffffiicciieenntt

ccoommbbuussttiioonn eettcc.

SSTTAARRTTIINNGG TTHHEE EENNGGIINNEE::

11.. EEnnggaaggee ddee--ccoommpprreessssiioonn lleevveerr bbeeffoorree ccrraannkkiinngg..

22.. CCrraannkk tthhee eennggiinnee aanndd ddiisseennggaaggee tthhee ddee--ccoommpprreessssiioonn lleevveerr..

33.. AAddjjuusstt tthhee ggoovveerrnnoorr ttoo aattttaaiinn tthhee rraatteedd ssppeeeedd..


11.. OOppeenn tthhee tthhrreeee wwaayy ccoorrkk ssoo tthhaatt ffuueell fflloowwss ttoo tthhee eennggiinnee ddiirreeccttllyy ffrroomm tthhee ttaannkk..

22.. OOppeenn tthhee ccoooolliinngg wwaatteerr vvaallvveess aanndd eennssuurree wwaatteerr fflloowwss tthhrroouugghh tthhee eennggiinnee..

33.. SSttaarrtt tthhee eennggiinnee aanndd aallllooww rruunnnniinngg oonn nnoo llooaadd ccoonnddiittiioonn ffoorr ffeeww mmiinnuutteess..

44.. LLooaadd eennggiinnee bbyy aaddddiinngg wweeiigghhttss uuppoonn tthhee hhaannggeerr..

55.. AAllllooww tthhee ccoooolliinngg wwaatteerr iinn tthhee bbrraakkee ddrruumm aanndd aaddjjuusstt iitt ttoo aavvooiidd ssppiilllliinngg..

66.. AAllllooww tthhee eennggiinnee ttoo rruunn aatt tthhiiss llooaadd ffoorr ffeeww mmiinnuutteess..

77.. AAddjjuusstt tthhee ccoooolliinngg wwaatteerr rreegguullaattoorrss ssuucchh tthhaatt tthhee tteemmppeerraattuurree rraaiissee ooff CCoooolliinngg wwaatteerr

ffoorr eennggiinnee jjaacckkeett iiss aarroouunndd 5500CC aanndd ffoorr ccaalloorriimmeetteerr aarroouunndd 225500CC..

88.. NNoottee tthhee ffoolllloowwiinngg rreeaaddiinnggss

aa)) EEnnggiinnee SSppeeeedd

bb)) WWeeiigghhtt oonn tthhee hhaannggeerr

cc)) SSpprriinngg bbaallaannccee

dd)) MMaannoommeetteerr

ee)) TTiimmee ffoorr 1100cccc ooff ffuueell ccoonnssuummppttiioonn

ff)) FFllooww ooff CCoooolliinngg wwaatteerr tthhrroouugghh CCaalloorriimmeetteerr..

gg)) FFllooww ooff CCoooolliinngg wwaatteerr tthhrroouugghh EEnnggiinnee..

hh)) IInnlleett aanndd oouuttlleett tteemmppeerraattuurreess ooff eennggiinnee ccoooolliinngg wwaatteerr

ii)) IInnlleett aanndd oouuttlleett tteemmppeerraattuurreess ooff ccaalloorriimmeetteerr ccoooolliinngg wwaatteerr

jj)) IInnlleett aanndd oouuttlleett tteemmppeerraattuurreess ooff eexxhhaauusstt ggaasseess

kk)) AAmmbbiieenntt tteemmppeerraattee

99.. RReeppeeaatt tthhee aabboovvee pprroocceedduurree ffoorr ddiiffffeerreenntt llooaaddss..

1100.. SSttoopp tthhee eennggiinnee aafftteerr rreemmoovviinngg llooaadd oonn tthhee eennggiinnee..

OOBBSSEERRVVAATTIIOONNSS::


11.. BBeeffoorree ssttaattiinngg tthhee eennggiinnee cchheecckk aallll tthhee ssyysstteemmss ssuucchh aass ccoooolliinngg ,, lluubbrriiccaattiioonn aanndd ffuueell

ssyysstteemm

22.. EEnnssuurree ooiill lleevveell iiss mmaaiinnttaaiinneedd iinn tthhee eennggiinnee uuppttoo rreeccoommmmeennddeedd lleevveell aallwwaayyss.. NNeevveerr

rruunn tthhee eennggiinnee wwiitthh iinnssuuffffiicciieenntt ooiill..

33.. NNeevveerr rruunn tthhee eennggiinnee wwiitthh iinnssuuffffiicciieenntt eennggiinnee ccoooolliinngg wwaatteerr aanndd eexxhhaauusstt ggaass

ccaalloorriimmeetteerr ccoooolliinngg wwaatteerr..

44.. BBeeffoorree ssttooppppiinngg tthhee eennggiinnee,, llooaadd oonn tthhee eennggiinnee sshhoouulldd bbee rreemmoovveedd..

SS..

NN

OO

LLooaadd oonn tthhee

bbrraakkee ddrruumm

SSpp

eeeedd

MMaannoommeetteerr

rreeaaddiinngg

AAii rr

hheeaadd

ccaauu

ssii nn

gg ff

ll ooww

(( HHaa))

mm oo

ff aaii rr

TTiimmee

ffoorr

1100

cccc ooff

ffuueell

EEnnggiinnee

ccoooolliinngg

wwaatteerr

tteemmppeerraattuurree

CCaalloorriimmeetteerr

wwaatteerr


CCaalloorriimmeetteerr

eexxhhaauusstt

ggaasseess


AAmmbb

iieenntt

TTeemm

ppeerraa

ttuurree

TT66OOCC II//PP OO//PP II//PP OO//PP II//PP OO//PP

WW11

kkgg SS

kkgg WW

kkgg RRPP

MM

hh11 hh22 hh11--hh22 SSeecc TT11OOCC TT22

OOCC TT11

00

CC TT33

OOCC TT44OOCC TT55

OOCC TT66OOCC

11

22

33

44

55

66

CCAALLCCUULLAATTIIOONNSS::

11.. EEnnggiinnee oouuttppuutt ((BBrraakkee PPoowweerr)) [[BB..PP]] == 100060

NT2

………… kkWW

WWhheerree,,

NN == RRaatteedd ssppeeeedd …….... RRppmm,,

WW00 == WWeeiigghhtt ooff hhaannggeerr

WW11 == WWeeiigghhtt oonn hhaannggeerr ……………….. kkgg

WW22 == sspprriinngg bbaallaannccee rreeaaddiinngg ………………..kkgg

RRee == EEffffeeccttiivvee bbrraakkee ddrruumm rraaddiiuuss == ((RR++rr)) …… mm

WWhheerree RR iiss BBrraakkee ddrruumm rraaddiiuuss

rr iiss RRooppee rraaddiiuuss

WW == NNeett LLooaadd == [[((WW11--WW22))++ WW00]] 99..8811 ……………… NN

TT == ((WW ** RRee))……………………NN--mm

22.. MMaassss ooff ffuueell ccoonnssuummppttiioonn ppeerr mmiinn,, mmff == 601000

.10X

dieselofGravitySp

t kkgg// mmiinn..

tt == TTiimmee ffoorr 1100cccc ooff ffuueell ccoonnssuummppttiioonn…………SSeecc

33.. HHeeaatt IInnppuutt,, HH//II == mmff xx CCvv ………….. kkJJ// mmiinn

CCVV iiss ccaalloorriiffiicc vvaalluuee ooff ggiivveenn ffuueell == 4433440000 KKJJ // kkgg

44.. AAccttuuaall AAiirr iinnttaakkee::

MMaannoommeetteerr rreeaaddiinngg hh11 == ……………………....mmmm ooff wwaatteerr

MMaannoommeetteerr rreeaaddiinngg hh22 == ……………………....mmmm ooff wwaatteerr

DDiiffffeerreennccee iinn wwaatteerr lleevveell,, hhww == 1000

21hh

………………..mm ooff wwaatteerr

EEqquuiivvaalleenntt aaiirr ccoolluummnn,, hhaa ==airofDensity

waterofDensityhw ==

16.1

1000wh ......mm.. ooff aaiirr

OOrriiffiiccee ddiiaammeetteerr,, dd == 00..0022 mm

AArreeaa ooff oorriiffiiccee,, aa == 4

)02.0( 2…………....mm22

55.. AAccttuuaall VVoolluummee ooff aaiirr iinnttaakkee,, VVaa == CCdd aa agh2 ………… mm33 // sseecc..

CCooeeffffiicciieenntt ooff DDiisscchhaarrggee,, CCdd == 00..6622

66.. MMaassss ooff aaiirr iinnttaakkee,, mmaa == a VVaa 6600…………kkgg // mmiinn

DDeennssiittyy ooff aaiirr a == 11..1166 KKgg//mm33

77.. TToottaall mmaassss ooff EExxhhaauusstt GGaass,, mmgg == mmaa ++ mmff …….. kkgg//mmiinn

TThhee ssppeecciiffiicc hheeaatt ooff eexxhhaauusstt ggaass iiss ddeetteerrmmiinneedd bbyy eeqquuaattiinngg

HHeeaatt lloosstt bbyy eexxhhaauusstt ggaass == HHeeaatt ccaarrrriieedd bbyy ccaalloorriimmeetteerr ccoooolliinngg wwaatteerr

88.. HHeeaatt lloosstt bbyy eexxhhaauusstt ggaass iinn ccaalloorriimmeetteerr

HHeegg == mmgg CCppgg ((TT44 –– TT55))…….... kkJJ//mmiinn

99.. HHeeaatt ggaaiinneedd bbyy ccaalloorriimmeetteerr ccoooolliinngg wwaatteerr

HHccww== mmccww CCppww ((TT33-- TT11)) kkJJ//mmiinn

1100.. HHeeaatt iinnppuutt,, HHII == mmff CCVV………… kkJJ//mmiinn

1111.. HHeeaatt EEqquuiivvaalleenntt ooff BB..PP,, HHBB..PP == BB..PP 6600 ……………….... kkJJ//mmiinn

1122.. HHeeaatt lloosstt bbyy eexxhhaauusstt ggaass,, HHeegg == mmgg CCppgg ((TT44 -- TT66)) …….... kkJJ//mmiinn

1133.. HHeeaatt CCaarrrriieedd bbyy eennggiinnee CCoooolliinngg wwaatteerr HHeeww == mmww CCppww ((TT22 –– TT11))…… kkJJ//mmiinn

1144.. HHeeaatt uunnaaccccoouunntteedd lloossss ,,HHuu == HHII –– ((HHBBPP ++ HHeeww ++ HHeegg)) ………… kkJJ//mmiinn

HHEEAATT BBAALLAANNCCEE SSHHEEEETT OONN MMIINNUUTTEE BBAASSIISS::

HHeeaatt

SSuupppplliieedd kkJJ//mmiinn %% Heat distributed kkJJ// mmiinn %%

HHeeaatt

ssuupppplliieedd bbyy

tthhee ffuueell

AA== 110000

HHeeaatt iinn BB..PP B= B/ AA==

HHeeaatt ccaarrrriieedd bbyy eennggiinnee CCoooolliinngg

wwaatteerr

C= C/ AA==

HHeeaatt CCaarrrriieedd bbyy eexxhhaauusstt ggaasseess D= D/ AA==

UUnnaaccccoouunntteedd lloosssseess

((rraaddiiaattiioonn,, ffrriiccttiioonn,, eettcc..,,))

E= E/ AA==

TToottaall AA== 110000 AA== 110000

RREESSUULLTT::--

RREETTAADDAATTIIOONN TTEESSTT OONN 44--SSTTRROOKKEE,, SSIINNGGLLEE

CCYYLLIINNDDEERR DDIIEESSEELL EENNGGIINNEE TTEESSTT RRIIGG

RREETTAARRDDAATTIIOONN TTEESSTT OONN 44--SSTTRROOKKEE,, SSIINNGGLLEE CCYYLLIINNDDEERR DDIIEESSEELL EENNGGIINNEE TTEESSTT RRIIGG

AAIIMM::

TToo ccoonndduucctt rreettaarrddaattiioonn tteesstt oonn 44--ssttrrookkee,, ssiinnggllee ccyylliinnddeerr ddiieesseell eennggiinnee,, ttoo ccaallccuullaattee

ffrriiccttiioonnaall ppoowweerr ddeevveellooppeedd bbyy tthhee eennggiinnee

EEQQUUIIPPMMEENNTT//AAPPPPAARRAATTUUSS::

11.. 44-- SSttrrookkee,, ssiinnggllee ccyylliinnddeerr DDiieesseell eennggiinnee wwiitthh rrooppee bbrraakkee ddrruumm ddyynnaammoommeetteerr..



MMaakkee :: KKiirrlloosskkaarr AAVV

BBoorree :: 8800mmmm



MMaaxx.. BB..PP :: 33..77KKWW ((55 HH..PP))

CCoommpprreessssiioonn RRaattiioo :: 1166 ..55::11

OOrriiffiiccee DDiiaammeetteerr :: 2200 mmmm

FFuueell OOiill :: DDiieesseell



TTHHEEOORRYY::

TThhee ffrriiccttiioonnaall ppoowweerr ooff aann II..CC.. eennggiinnee iiss ddeetteerrmmiinneedd bbyy tthhee ffoolllloowwiinngg mmeetthhooddss

aa)) WWiilllliiaann’’ss lliinnee mmeetthhoodd

bb)) IInnddiiccaattoorr aarreeaa mmeetthhoodd

cc)) RReettaarrddaattiioonn tteesstt

dd)) MMoottoorriinngg tteesstt

ee)) MMoorrssee tteesstt..

RREETTAARRDDAATTIIOONN TTEESSTT::

TThhiiss tteesstt iinnvvoollvveess tthhee mmeetthhoodd ooff rreettaarrddiinngg tthhee eennggiinnee bbyy ccuuttttiinngg tthhee ffuueell

ssuuppppllyy.. WWhheenn tthhee eennggiinnee iiss ssttooppppeedd ssuuddddeennllyy iittss rreettaarrddaattiioonn iinn ssppeeeedd iiss ddiirreeccttllyy rreellaatteedd ttoo

tthhee ffrriiccttiioonnaall rreessiissttaannccee iinnssiiddee tthhee eennggiinnee.. TThhee eennggiinnee iiss mmaaddee ttoo rruunn aatt nnoo llooaadd aanndd rraatteedd

ssppeeeedd ..wwhheenn tthhee eennggiinnee iiss rruunnnniinngg uunnddeerr sstteeaaddyy ooppeerraattiinngg ccoonnddiittiioonnss tthhee ssuuppppllyy ooff ffuueell iiss

ccuutt ooffff aanndd ssiimmuullttaanneeoouussllyy tthhee ttiimmee ooff ffaallll iinn ssppeeeeddss bbyy ssaayy 2200%% ,, 4400%%,, 6600%% ,, 8800%% ooff tthhee

rraatteedd ssppeeeedd iiss rreeccoorrddeedd.. TThhee tteessttss aarree rreeppeeaatteedd oonnccee aaggaaiinn wwiitthh 5500%% llooaadd oonn tthhee eennggiinnee.. AA

ggrraapphh ccoonnnneeccttiinngg ttiimmee ffoorr ffaallll iinn ssppeeeedd ((xx-- aaxxiiss )) aanndd ssppeeeedd ((yy –– aaxxiiss )) aatt nnoo llooaadd aass wweellll aass

5500 %% llooaadd ccoonnddiittiioonnss iiss ddrraawwnn aass sshhoowwnn iinn ffiigg..

110000rrppmm

SSppeeeedd

tt33 tt22

TTiimmee

GGrraapphh ffoorr rreettaarrddaattiioonn TTeesstt

IInn tthhiiss sseett uupp ttoo ssttoopp tthhee eennggiinnee rruunnnniinngg ffrroomm ssuuppppllyy ooff ffuueell aa vvaallvvee iiss pprroovviiddeedd.. AAss

tthhee eennggiinnee hhaass rruunn ffoorr ssuuffffiicciieenntt ttiimmee,, tthhee vvaallvvee iiss ccuuttooffff aanndd aatt tthhee ssaammee ttiimmee ddiiggiittaall ttiimmeerr iiss

sswwiittcchheedd oonn.. TTiimmee ffoorr rreedduuccttiioonn iinn ssppeeeedd ttiillll aa ppaarrttiiccuullaarr ssppeeeedd iiss nnootteedd..


11.. CChheecckk tthhee ffuueell aanndd lluubbrriiccaattiinngg ooiill lleevveellss..

22.. SSuuppppllyy tthhee ffuueell ttoo tthhee eennggiinnee..

33.. OOppeenn tthhee ccuutt ooffff vvaallvvee ttoo eenntteerr tthhee ffuueell iinnttoo tthhee eennggiinnee

44.. NNooww ssttaarrtt tthhee eennggiinnee..

55.. CCoonnnneecctt tthhee wwaatteerr ssuuppppllyy ttoo tthhee eennggiinnee ffoorr ccoooolliinngg

66.. AAfftteerr iinniittiiaall wwoorrmm uupp tthhee eennggiinnee,, ccuutt ooff tthhee ffuueell ssuuppppllyy uussiinngg ((ccuutt ooffff vvaallvvee)) aatt nnoo llooaadd..

77.. TThhee ssuuppppllyy ooff ffuueell iiss ccuutt ooffff aanndd ssiimmuullttaanneeoouussllyy tthhee ttiimmee ooff ffaallll iinn ssppeeeeddss bbyy ssaayy 2200%%

,, 4400%%,, 6600%% ,, 8800%% ooff tthhee rraatteedd ssppeeeedd iiss rreeccoorrddeedd bbyy uussiinngg ddiiggiittaall ttiimmeerr aanndd ddiiggiittaall

RRPPMM iinnddiiccaattoorr..

88.. TThhee aabboovvee pprroocceedduurree iiss ffoolllloowweedd ffoorr 5500%% llooaadd ((ii..ee 77KKgg))..

BBeeffoorree SSTTAARRTTIINNGG TTHHEE EENNGGIINNEE::

11.. CChheecckk tthhee DDiieesseell LLeevveell iinn tthhee ddiieesseell ttaannkk..

22.. CChheecckk tthhee WWaatteerr ffllooww tthhrroouugghh EEnnggiinnee ccyylliinnddeerr..

33.. FFiirrsstt,, sswwiittcchh --OONN tthhee MMCCBB (( MMaaiinnss )) ooff tthhee ccoonnttrrooll ppaanneell aatt tthhee rriigghhtt bboottttoomm

ssiiddee ..

44.. EEnnssuurree tthhaatt wwaatteerr iiss fflloowwiinngg tthhrroouugghh tthhee eennggiinnee..

OOBBSSEERRVVAATTIIOONNSS

LLeett,,

tt22 aanndd tt33 bbee tthhee ttiimmee ooff ffaallll aatt nnoo llooaadd aanndd 5500%% llooaaddss

ωω == AAnngguullaarr vveelloocciittyy iinn rraadd//sseecc

α =dt

dw= Angular acceleration in rad/sec2

SS.. NNoo DDrroopp iinn ssppeeeedd TTiimmee ffoorr ffaallll ooff

ssppeeeedd aatt nnoo llooaadd,,

SSeecc

TTiimmee ffoorr ffaallll ooff

ssppeeeedd aatt 77KKgg llooaadd,,

SSeecc

11..

22..

33..

44..

55..

Torque, T= Moment of inertia ×Angular acceleration

TT==II××dt

dw

Moment of inertia of rotating parts is constant throughout the test

T=mk2 ×dt

dw (I = mk2 )

dw= dtI

T (eq1)

Now integrating the equation 1 between the limits ω1 aanndd ωω22

2

1

w

wdw= dt

I

Tt

t

2

1

2

1

w

ww == 12 ttI

T

Let, TF be the frictional torque and TL be the load torque . At no load condition both frictional and load torques will act. Hence at no load condition

ω2 – ω1= 02 tI

TF (eq 2)

Where TF = frictional torque Similarly for load condition

ω2 – ω1= 03 tI

TL (eq 3)

where TL = load torque

tt33 ((TTff++TTLL)) == ((ωω22 –– ωω11))mmkk22

tt33 ((TTff++TTLL)) == TTff××tt22 ((ffrroomm eeqq 22))

3

2

t

t=

I

TT LF

3

2

t

t = 1+

F

L

T

T

F

L

T

T =

3

32

t

tt

TF = TL×32

3

tt

t


11.. DDoonn’’tt ssttaarrtt oorr ssttoopp tthhee eennggiinnee wwiitthh llooaadd..

22.. DDoonn’’tt ffoorrggeett ssuuppppllyy ooff ccoooolliinngg wwaatteerr ttoo tthhee eennggiinnee..

33.. AAfftteerr ssttaarrttiinngg tthhee eennggiinnee rreemmoovvee tthhee hhaannddllee ccaarreeffuullllyy ffrroomm tthhee sshhaafftt..

44.. TTaakkee tthhee ttiimmee ccaarreeffuullllyy ffoorr ddrrooppppiinngg ooff tthhee ssppeeeedd

SSAAMMPPLLEE CCAALLCCUULLAATTIIOONNSS::

LLooaadd TToorrqquuee oonn ddrruumm ((TTLL)) == 81.9rM NN mm

MM-- MMaassss iinn KKgg ooff sspprriinngg BBaallaannccee

rr -- RRaaddiiuuss ooff ttoorrqquuee aarrmm == 2

015.036.0 mm

FFrriiccttiioonnaall llooaadd TToorrqquuee (( FT )) == LTtt

t

32

3

tt22

== RReettaarrddaattiioonn ttiimmee aatt nnoo llooaadd

tt33 == RReettaarrddaattiioonn ttiimmee aatt 5500%% llooaadd

FFrriiccttiioonnaall ppoowweerr ((FF..PP)) == 60

2 FTN WW

BBrraakkee ppoowweerr BB..PP == 60

2 TN WW

MMeecchhaanniiccaall EEffffiicciieennccyy == 100.

.

PI

PB

RREESSUULLTT::--

MMOORRSSEE TTEESSTT OONN 44--SSTTRROOKKEE,, 44-- CCYYLLIINNDDEERR

PPEETTRROOLL EENNGGIINNEE TTEESSTT RRIIGG

MORSE TEST ON 4-STROKE, 4-CYLINDER PETROL ENGINE AIM: To conduct Morse test on a 4-stroke multi cylinder (4 – cylinder) petrol engine to

establish friction power & mechanical efficiency

EQUIPMENT REQUIRED:

1. 4-stroke,4 -cylinder petrol engine with a hydraulic dynamometer with provision to cut

off ignition to each cylinder independently.

2. Tachometer (0-2000 rpm).

3. Stop watch


MMaakkee :: PPrreemmiieerr

NNoo ooff ccyylliinnddeerrss :: 44

BBoorree :: 6688 mmmm



BB..PP :: 77..3355 KKww ((1100 HHpp))

FFuueell :: PPeettrrooll

SSppeecciiffiicc GGrraavviittyy ooff ppeettrrooll :: 00..771166

CCaalloorriiffiicc vvaalluuee ooff ppeettrrooll :: 4477110000 KKJJ//kkgg

CCoommpprreessssiioonn RRaattiioo :: 77..88::11

OOrriiffiiccee ddiiaammeetteerr :: 2200 mmmm


TThhee tteesstt rriigg ccoonnssiissttss ooff aa mmuullttii ccyylliinnddeerr ppeettrrooll eennggiinnee ccoouupplleedd ttoo aa hhyyddrraauulliicc

ddyynnaammoommeetteerr.. TThhee eennggiinnee iiss 44--ccyylliinnddeerr,, 44--ssttrrookkee vveerrttiiccaall eennggiinnee ddeevveellooppiinngg 77..3355KKww aatt

11550000 rrppmm.. TThhiiss ttyyppee ooff eennggiinnee iiss bbeesstt ssuuiitteedd ffoorr aauuttoommoobbiilleess wwhhiicchh ooppeerraattee aatt vvaarryyiinngg

ssppeeeedd.. TThhee eennggiinnee iiss ffiitttteedd oonn aa rriiggiidd bbeedd aanndd iiss ccoouupplleedd tthhrroouugghh aa fflleexxiibbllee ccoouupplliinngg ttoo aa

hhyyddrraauulliicc ddyynnaammoommeetteerr tthhaatt aaccttss aass tthhee llooaaddiinngg ddeevviiccee.. AAllll tthhee iinnssttrruummeennttss aarree mmoouunntteedd oonn

aa ssuuiittaabbllee ppaanneell bbooaarrdd.. FFuueell ccoonnssuummppttiioonn iiss mmeeaassuurreedd wwiitthh aa bbuurreettttee aanndd aa 33--wwaayy ccoorrkk

wwhhiicchh rreegguullaatteess tthhee ffllooww ooff ffuueell ffrroomm tthhee ttaannkk ttoo tthhee eennggiinnee..

AAiirr ccoonnssuummppttiioonn iiss mmeeaassuurreedd bbyy uussiinngg aa MM..SS.. ttaannkk,, wwhhiicchh iiss ffiitttteedd wwiitthh aa ssttaannddaarrdd

oorriiffiiccee aanndd aa UU--ttuubbee wwaatteerr mmaannoommeetteerr tthhaatt mmeeaassuurreess tthhee pprreessssuurreess iinnssiiddee tthhee ttaannkk..

TToo ccoonndduucctt MMoorrssee tteesstt,, aann aarrrraannggeemmeenntt iiss pprroovviiddeedd ttoo ccuutt ooffff tthhee iiggnniittiioonn ttoo eeaacchh

ssppaarrkk pplluugg..

THEORY:

The frictional power of an I.C. engine is determined by the following methods:

f) William’s line method

g) Indicator area method

h) Motoring test

i) Morse test

The Morse test is applicable for multi cylinder petrol (or) diesel engine. The engine

is run at the rated speed and the output is measured. Then one cylinder is made not to fire

by Cut-off ignition, under this condition, the other cylinder operates the engine. As a

consequence the speed of the engine falls. The output is measured by restoring the speed

to the original value by decreasing the load. The difference between two outputs gives the

indicated power of the cylinder cutout.

Thus the indicated power of all cylinders can be evaluated and by deducting brake

power from the indicated power of all cylinders, the frictional power of the engine can be

estimated.

Let I.P of cylinders 1, 2, 3 & 4, be I.P1, I.P2, I.P3&I.P4 respectively. Let Frictional

power of the engine be ‘F.P’ at a given load. Thus for a four cylinder engine.

I.P1+I.P2+I.P3+I.P4 – F.P = B .P ………. (1)

Where B.P= Brake Power of engine when all cylinders are working.

When first cylinder is cut out I1 = 0, but Friction power of the engine remains at F.P

Then I.P2 + I.P3 + I.P4 - F.P = B.P1 …….. (2)

By (1) – (2) we have I.P1 = B.P – B.P1

Similarly I.P2 = B.P – B.P2

I.P3 = B.P – B.P3

I.P4 = B.P – B.P4

I.P. of the engine I.P = I.P1 + I.P2 + I.P3 + I.P4

F.P. of the engine F.P = I.P – B.P

STARTING THE ENGINE:

1. Disengage the clutch and start the engine using the ignition key.

2. Engage the clutch slowly.

3. Adjust the throttle valve, so that the engine attains rated speed.

PROCEDURE:

1. Open the three- way cork so that fuel flows to the engine directly from the tank

2. Open the cooling water valves and ensure water flows through the engine

3. Open the water line to the hydraulic dynamometer

4. Start the engine and allow to run on No Load condition for few minutes

5. Operate the throttle valve so that the engine picks up the rated speed

6. Load the engine at full load and maintain the speed at rated rpm i.e., 1500 rpm

by adjusting the throttle and dynamometer loading wheel.

7. Allow the engine to run at this load for a few minutes.

8. Cut-off ignition to the first cylinder, and thus speed is decreased.

9. Without disturbing the throttle valve position, decrease the load on the engine,

until the original speed is restored.

10. Note the dynamometer reading, restore the ignition to the first cylinder

11. Repeat the above procedure by cutting off ignition to each of the cylinders.

12. Note the dynamometer readings for each cylinder when they are cut -off.

13. Engine stopped after removing the load.

PRECAUTIONS:

1. Before stating the engine check all the systems such as cooling , lubrication and

fuel system

2. Ensure oil level is maintained in the engine upto recommended level always.

Never run the engine with insufficient oil.

3. Never run the engine with insufficient engine cooling water and exhaust gas

calorimeter cooling water.

4. For stopping the engine, load on the engine should be removed.

OBSERVATIONS:

RRaatteedd SSppeeeedd==11550000 rrppmm

S. No

Condition Dynamometer load (W) Kg

B.P,

KW

I.P,

KW

F.P

KW

1 All cylinders working

W =

2 1st cylinder cut-off W1=

3 2nd cylinder cut-off W2=

4 3rd cylinder cut-off W3=

5 4th cylinder cut-off W4=

SAMPLE CALCULATIONS:

`B.P =60000

2 TN ……. KW (where T= torque = W×R)

B.P1= 60000

2 1TN ……. KW (R=320mm)

B.P2=60000

2 2TN .…… KW

B.P3= 60000

2 3TN …… KW

B.P4= 60000

2 4TN …… KW

I.P1 = B.P-B.P1 …… KW

I.P2 = B.P-B.P2…… KW

I.P3 = B.P-B.P3 …… KW

I.P4 = B.P-B.P4….. KW

I.P = I.P1+I.P2+I.P3+I.P4 . .KW

F.P = I.P-B.P…… Kw

Frictional power, F.P = KW

Mechanical efficiency m = 100P.I

P.B

RESULT:-

PPEERRFFOORRMMAANNCCEE TTEESSTT OONN 22-- SSTTRROOKKEE,,

SSIINNGGLLEE CCYYLLIINNDDEERR

PPEETTRROOLL EENNGGIINNEE TTEESSTT RRIIGG

PERFORMANCE TEST ON 2- STROKE, SINGLE CYLINDER PETROL ENGINE TEST RIG

AIM: To conduct a load test on a single cylinder, 2- Stroke petrol engine and study its

performance under various loads.

EQUIPMENT / APPARATUS:

1. 2-Stroke, Single Cylinder Petrol Engine with Resistance load bank

2. Tachometer

3. Stop Watch

SPECIFICATIONS: Make : Bajaj

Stroke : 57mm

Bore : 57mm

Rated R.P.M : 3000rpm

Output : 3 hp

Fuel : Petrol

Specific Gravity of petrol : 0.716

Calorific Value of petrol : 47100 KJ/Kg

Lubrication : 3% mixture of self mixing oil and

petrol

DESCRIPTION:

This Petrol engine is an air cooled, single cylinder, Vertical, 2-stroke engine. The

engine is kick started. The petrol engine is coupled to a Resistance load dynamometer to

absorb the power produced. The dynamometer is provided with load controller switches for

varying the load. Fuel consumption is measured with a burette and a stop watch. A three-

way cork, which regulates the flow of petrol from the tank to the engine.

PROCEDURE:

1. Open the three way cork so that fuel flows to the engine directly from the tank.

2. Start the engine and allow running on no load condition for few minutes.

3. Load the engine, by switching on the resistance from the load bank.

4. Note the following readings

a) Speed.

b) Voltage and Current.

c) Time taken for 10 cc of petrol consumption.

5. Repeat the above procedure at different loads.

6. Stop the engine after removing load on the engine

PRECAUTIONS

1. Use only petrol mixed with 2T oil – use higher oil /petrol ratio to compensate for the lack of cooling air ( air flow over the engine while moving ) in the stationary test rig

2. Changing gear oil regularly.

3. Never run the engine with insufficient fuel

MMOODDEELL GGRRAAPPHHSS::

BB..PP,, KKWW

mm

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BB..PP ,, KKWW

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BB..PP,, KKWW

ii tthh,, %%

BB..PP,, KKWW

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LLooaadd oonn tthhee

rreessiissttaannccee llooaadd

bbaannkk SSpp

eeee

dd

MMaannoommeetteerr

rreeaaddiinngg

AAii rr

hheeaa

dd cc

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mm oo

ff aa

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11

22

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66

BB..PP,, KKWW FF.. PP,, KKWW TT

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SAMPLE CALCULATIONS:

1. Air head causing flow = 100

h

air

water

…………………….. mm ooff aaiirr

22.. AAccttuuaall vvoolluummee ooff aaiirr iinnttaakkee==VVaa== CCdd AA00 agH2 ==

WWhheerree CCdd== 00..6622

AA00== 33..1144 XX 1100--44

33.. TThheeoorreettiiccaall vvoolluummee ooff aaiirr == VVtthh == 60

N Ls D 4

2

mm33//SSeecc

44.. VVoolluummeettrriicc eeffffiicciieennccyy == 100V

V

th

a

55.. MMaassss ooff ffuueell == 1000

71.0 Q mm//sseecc

QQ == t

10 cc/ sec

66.. BBrraakkee ppoowweerr BB..PP == 100

g

IV

WW

g = 80 %

77.. BBrraakkee ssppeecciiffiicc ffuueell ccoonnssuummppttiioonn,, BBSSFFCC == PB

CFT

.

..…………....KKgg //KKww--hhrr

88.. IInnddiiccaatteedd ppoowweerr II..PP == BB..PP ++ FF..PP

SS.. NNOO

II..SS..FF..CC BB..SS..FF..CC

AAccttuuaall

vvoolluummee

ooff aaiirr

VVaa

MMaassss ooff

aaiirr

TThheeoorreettii

ccaall

vvoolluummee

ooff aaiirr

VVtthh

EEffffiicciieenncciieess

kkgg//kkww--hh kkgg//kkww--hh mm33//ss kkgg//ss mm33//ss VVooll BBtthh IItthh mm

11

22

33

44

55..

66..

99.. IInnddiiccaatteedd ssppeecciiffiicc ffuueell ccoonnssuummppttiioonn,, IISSFFCC ==PI

CFT

.

..…………KKgg //KKww--hhrr

1100.. BBrraakkee tthheerrmmaall eeffffiicciieennccyy,, BB tthh == vf Cm

PB

.

1111.. IInnddiiccaatteedd tthheerrmmaall eeffffiicciieennccyy,, II tthh == vf Cm

PI.

1122.. MMeecchhaanniiccaall eeffffiicciieennccyy,, mm == 100.

.

PI

PB

RRESULT::--

AIM:

To conduct a performance test on a refrigerator with Freon 12 refrigerant to

determine the coefficient of performance. EQUIPMENT /APPARATUS:

1. Refrigeration test rig

2. Measuring jar

3. Stop watch

SPRCIFICATIONS:

Make : Altech

Compressor : 1 / 3 Ton of refrigeration

Condenser : Air Cooled

Expansion Device : i ) Capillary Tube

ii) Solenoid Valve

Evaporator Coil : Immersed in water Tank of stainless

steel

Refrigerant : Freon – 22. DESCRIPTION:

The test rig consists of a hermetically sealed compressor. The compressed

refrigerant from the compressor is sent to an air cooled condenser and the condensate in

liquid form is sent to the expansion valve /capillary tube for throttling. Due to throttling

temperature of the refrigerant falls and the cold refrigerant absorbs heat from the water in

the evaporator tank. The refrigerant is then returned to the compressor.

A suitable filter and a transparent rotameter to visually observe the liquid.

Refrigerant is fitted in the refrigerant line from condenser to evaporator. A thermocouple is

provided to measure the temperature of the water in the evaporator tank. An energy meter

is provided to measure the energy input to the compressor. Suitable pressure gauges are

provided at the compressor inlet (evaporator outlet),

PPEERRFFOORRMMAANNCCEE TTEESSTT OONN RREEFFRRIIGGEERRAATTIIOONN

TTEESSTT RRIIGG

Condenser inlet (compressor outlet), condenser outlet (before throttling) and evaporator

inlet (after throttling) to study the refrigeration cycle operating between the two pressures. A

thermostat is provided for the cutting off the power to compressor when the water

temperature reaches asset value. A voltmeter and an ammeter are provided to monitor the

inlet power supply. A voltage stabilizer is provided for the protection of compressor.

Provisions are provided in the refrigerant pipe lines for charging the test rig with additional

refrigerant if necessary. Additional 4 No’s of thermocouples are fitted at the condenser and

evaporator inlet and outlet for studying the temperature at the 4 points in the refrigeration

cycle

THEORY:

A refrigerator consists of a compressor connected by suitable pipelines to a

condenser, a capillary tube and an evaporator. Refrigerant (Freon12) in vapor state from

the evaporator is compressed in the compressor and sent to the condenser. Here it

condenses’s in to liquid and it is then throttled. Due to throttling temperature of refrigerant

drops and the cold refrigerant passes through the evaporator absorbing heat from the

object to be cooled. The refrigerant is then returned to the compressor and the cycle is

completed

PROCEDURE:

1. Fill up the evaporator tank with a know quantity of water (say 10-15 litres).

2. Switch on the compressor.

3. After about 5 minutes (after steady state had set in) note the initial energy meter

reading and water temperature in the evaporator.

4. After a known period of time, say 30 minutes note down the energy meter reading

and water temperature.

5. Calculate the actual COP.

6. Note the Refrigerant pressures at compressor inlet (evaporator outlet), condenser

inlet (compressor outlet), condenser outlet (before throttling) and evaporator inlet

(after throttling) using the pressure gauges.

7. Note the Temperatures at compressor inlet (evaporator outlet), condenser inlet

(compressor outlet), condenser outlet (before throttling) and evaporator inlet (after

throttling) using the thermocouples provided.

8. Draw pressure- enthalpy diagram.

9. Calculate the theoretical COP

10. Calculate the relative cop

PRECAUTIONS:

1. Before noting the water temperature, physically Stir the water to ensure that the

temperature is uniform in the water tank

2. Since COP depends upon the evaporator temperature and condenser temperature,

the calculated COP (which is an average value) will be different for varying

evaporator, condenser and water temperatures.

3. When the compressor turns off (by the thermostat) or is switched off manually, do

not turn on the power immediately. Allow a few minutes for the pressure in the

compressor inlet and outlet to equalize. The time delay provided in the voltage

stabilizer is for this purpose only. Immediate starting

will cause under load on the compressor and may even lead to burn out SAMPLE CALCULATIONS:

ACTUAL COP:

Quantity of water in evaporator tank, m =…………….. Kg

Time taken for experiment, t =………………..hours

Initial temperature of water,T0 =………..0C

Final temperature of water, Tf = ………..0C

Initial energy meter reading, E0 = …………Kwh

Initial energy meter reading, Ef = ……….Kwh

Refrigerating effect per hour = m(T0 - T f )

t

Energy input = E f Eo

…..KW

t

Actual Coefficient of Performance, COP = refrigerating effect

Energy input

Actual COP =

THEORETICAL COP:

Theoretical COP is calculated from the pressure measured from pressure gauges

(evaporator and condenser pressures) and the temperatures measured from four

thermocouples located at four points of the thermodynamic cycle (refer figure 1).

S.No Reading Temperature, Pressure, Pressure,

0C Psi Bar

1 Condenser inlet

2 Condenser outlet

3 Evaporator inlet

4 Evaporator outlet

Note: Bar = Psi +1

14.5

From P-h diagram for R-12 Enthalpy of refrigerant at evaporator outlet, (before compression) h1 = ….Kj/Kg

Enthalpy of refrigerant at condenser inlet, (after compression) h2 = … …..Kj /kg

Enthalpy of refrigerant at condenser outlet, (before throttling) h3 = ………..Kj/Kg

Enthalpy of refrigerant at evaporator inlet, (after throttling) h4 = …………….Kj/Kg

Theoretical COP = (h1

h4

)

(h2 h1 )

Actual COP

Relative COP = Theoritical COP

RESULT :

AASSSSEEMMBBLLYY AANNDD DDIISSAASSSSEEMMBBLLYY OOFF

IICC EENNGGIINNEESS

Aim: To study the different types of I.C engines, various parts of I.C engines, cycles of

operation etc.,

Introduction:

Any type of engine, which derives heat energy from the combustion of fuel and converts

this energy into mechanical work, is termed as a heat engine. These are classified as

1. External Combustion engines (E.C)

2. Internal Combustion engines (I.C)

If the combustion of fuel takes place outside the working cylinder then the

engine is called External Combustion Engine. If the combustion takes place inside the

working cylinder the engine is called Internal Combustion Engine. The most common

examples of E.C engines are steam engines and steam turbines. I.C engines are used in

scooters, cars, locomotives, agriculture and earth moving machinery, power generation and

in many industrial applications. The advantages of I.C engines over E.C engines are high

efficiency, simplicity, compactness, light weight, easy starting and low cost.

Classification of I.C Engines:

I.C Engines are classified as follows

1. According to the fuel used: Petrol engine, Diesel engine and Gas engine.

2. According to cycle of operations: 2-stroke engine and 4-stroke engine

3. According to the method of ignition: Spark ignition (S.I) engine, Compression Ignition

(C.I) engine.

4. According to the number of cylinders: single cylinder engine, multi cylinder engine.

5. According to the method of cooling the cylinder: Air-cooled engine and Water-cooled

engine.

6. According to the arrangement of cylinder: Horizontal engine, Vertical engine and

Radial engine.

I.C Engine Parts and their Function:

An I.C engine consists of many different parts, however the main components are

described below.

1.Cylinder: The heart of the engine is the cylinder and its primary function is to contain the

working fuel under pressure and the secondary function is to guide the piston. To avoid the

wear of the cylinder block cylinder liners are provided. The cylinder is made of Gray Cast

Iron.

2.Cylinder Head: One end of the cylinder is closed by means of a removable cylinder

head, which usually contains the inlet valve for admitting fuel and exhaust valve for

discharging products of combustion. The valves are operated by means of cams geared to

the engine shaft. The cylinder head is usually made of cast iron or alloy cast iron containing

Nickel, Chromium and Molybdenum.

3.Piston: The piston used in I.C engines is usually of trunk type and are open at one end.

The main function of the piston is to receive the impulse from the expanding gas and

transmit the energy to the crankshaft through the connecting rod. At the same time the

piston must also disperse a large amount of heat from the combustion chamber to the

cylinder walls. Pistons are made of cast iron or Aluminum alloys for lightness.

4. Piston Rings: These are circular rings and made of special steel alloys, which retain

elastic properties even at high temperatures. The piston rings are housed in the

circumferential grooves provided on the outer surface of the piston. Generally there are two

sets of rings mounted on the piston. The function of the upper rings is to provide air tight

seal to prevent leakage of the burnt gases into the lower portion. Similarly the function of

the lower rings is to provide effective seal to prevent leakage of the oil into the engine

cylinder.

5.Connecting Rod: One end of the connecting rod is connected to the piston through

piston pin and the other end is connected to the crank through the crank pin. The usual

cross section of connecting rod is I-section or H-section and these are made of carbon

steel or alloy steel. The main function is to transmit force from the piston to the crankshaft.

Moreover, it converts reciprocating motion of the piston into the circular motion of the crank

shaft in the working stroke.

6.Crank shaft: crank shaft consists of the shaft part which revolve in the main bearing. The

big end of the connecting rod is connected to the crank pin. The crank web connects to the

crank pin and shaft part. The function of the crankshaft is to transform reciprocating motion

into rotary motion. Crankshafts are made of carbon steel.

7.Cam shaft: It is driven from the crank shaft by timing gears on a chain. It operates the

intake valve and the exhaust valve through the cams and followers, push rods and rocker

arms.

8.Fly wheel: It is a big wheel mounted on the crank shaft whose function is to reduce the

vibrational fluctuations. It stores excess energy during power stroke and releases during

the other strokes.

Cycle of operation: The number of strokes of the piston required to complete the cycle

varies with the type of engine. There are two types of engines namely four stroke cycle

engine and two stroke cycle engine. A four-stroke cycle engine requires four strokes of

piston or two revolutions of the crankshaft to complete one cycle. In a two-stroke engine

there are two strokes of the piston or one revolution of the crankshaft to complete one

cycle. The four stroke and two stroke engines are further divided into petrol and diesel

engines according to the type of fuel used.

Four stroke petrol / Diesel engine: The four stroke engine utilizes four strokes namely

suction stroke, compression stroke, power stroke, and exhaust stroke for completion of a

cycle and it has two valves, one for the inflow of the air fuel mixture or pure air and the

other for the exhaust of burnt gases. At the start of the working cycle, the piston is at the

top dead center position (TDC). As the piston begins its outward stroke the inlet valve

opens and a mixture of fuel and air in metered proportions flows in, If the engine is of the

spark ignition type only, air flows in through the inlet valve. When the piston starts moving

back into the cylinder, both inlet and exhaust valves closes. The air or air fuel mixture thus

trapped between the piston and the cylinder head is now compressed until the piston

reaches the TDC at the end of compression stroke. Just before the end of the compression

stroke of the piston ignition occurs due to a spark in case of petrol engines or a spray of oil

injected into the cylinder in case of diesel engines. In either case, the thermal energy

released makes the compressed gas expand rapidly and drives the piston outwards. The

resulting stroke is called the power stroke. As the piston completes the power stroke and

returns T.D.C, the exhaust valve opens and the burnt exhaust gases in the cylinder are

driven out. At the instant the, piston reaches the TDC position, the exhaust valve closes

and the inlet valve will be ready to open, starting a new cycle of operation again.

Two stroke S.I / C.I engines:

The two stroke engines utilize only two strokes (Compression stroke and power

stroke) for the completion of a cycle. In two-stroke engine there are two ports. One in the

inlet and one in the outlet for gasses. The opening and closing of the ports depends on the

position of the piston in the cylinder. The piston is at T.D.C both outlet and transfer ports

are closed when the compressed air fuel mixture or air in the cylinder is about to be ignited

by either a sparking device or fuel injection. When piston travels back during the power

stroke, it uncovers the exhaust port first and a moment later the transfer port. The opening

of the transfer port puts the cylinder in contact with the crankcase containing a slightly

compressed air fuel mixture or air. The incoming fresh charge helps in driving out the burnt

gases through the exhaust port. The head of the piston being shaped to assist this

scavenging action. As the piston returns into the cylinder, it covers both the transfer and

exhausts ports and compresses the trapped gas until it reaches the T.D.C position. At the

same time a fresh charge is drawn into the crankcase through the inlet port. A cycle is thus

completed with one power stroke in every two-piston strokes.

In a two stroke engine a small amount of burnt gas always remains in

the cylinder along with the fresh charge when the piston covers the ports and starts

compressing the gases trapped inside. Moreover, since both transfer port and exhaust

ports are simultaneously open during part of the piston stroke, some of the incoming fresh

charge escapes with the burnt gases. As a result the efficiency of a two stroke engine is

lower, further two stroke engines consume large amounts of lubricating oil compared with

four stroke engines and are likely to be noisier because of the sudden opening of the

exhaust ports.

Valve Timing Diagram:

The valve timing diagram shows the position of the crank when the various

operations, i.e. suction, compression, expansion and exhaust begin and end.

The valve timing is the regulation of the positions in the cycle at which the valves are

set to open and close. Since the valves requires a finite period of time to open or close

without a rupture, a slight ‘lead’ time is necessary for the proper operation. The design of

valve operating can provide for smooth transition from one position to the other, while cam

setting determines the timing of the valve.

Theoretically it may be assumed that the valves open and close and spark (or

injection of fuel) occurs at the engine dead centers. However, in actual operation the valves

do not operate at it center positions but operate some degrees away on either side of the

dead centers. The opening occurs earlier and the exhaust continues even at later crank

angles. The ignition is also timed to occur earlier. The injection of fuel in the case of diesel

engine is also timed to occur in advance of the completion of compression stroke.

The timing of these events referred in terms of crank angles from dead center

positions, is presented on a valve-timing diagram. The correct timings are of fundamental

importance for the efficient and successful running of the I.C engine.

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