IC Engine Lab Manual
11
SATHYABAMA UNIVERSITY JEPPIAAR NAGAR, CHENNAI - 600 119. DEPARTMENT OF MECHANICAL ENGINEERING IV SEMESTER PART TIME MECHANICAL ENGINEERING CODE: 615PT450 - IC ENGINES LAB LIST OF EXPERIMENTS: I.PERFORMANCE TEST ON CONSTANT SPEED ENGINE 2. PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR 3. VALVE TIMING DIAGRAM 4. PORT TIMING DIAGRAM 5. OPTIMUM COOLING TEST
Transcript of IC Engine Lab Manual
SATHYABAMA UNIVERSITY JEPPIAAR NAGAR CHENNAI - 600 119
DEPARTMENT OF MECHANICAL ENGINEERING
IV SEMESTER PART TIME MECHANICAL ENGINEERING
CODE 615PT450 - IC ENGINES LAB
LIST OF EXPERIMENTS
IPERFORMANCE TEST ON CONSTANT SPEED ENGINE
2 PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
3 VALVE TIMING DIAGRAM
4 PORT TIMING DIAGRAM
5 OPTIMUM COOLING TEST
SIVASANKAR
Cross-Out
SIVASANKAR
Text Box
5Frictional power by retardation test1313
PERFORMANCE TEST ON CONSTANT SPEED ENGINE DETERMINATION OF FRICTION POWER BY PERFORMANCE TEST
AIM To conduct a performance test on a constant speed engine and to find the mechanical
efficiency using negative horse power method
INTRODUCTION The experiment is conducted on a diesel engine of the following specifications
make COMET type vertical Automatic governing loading mechanical brake
brake power 37 KW rated speed 1500 RPM bore 8 cM stroke 11 CM
Radius of the brake drum 1675 cm
The energy supplied to the engine is by way of burning the fuel The thermal energy generated is known as the calorific value of the fuel A part ofmiddot this energy alone get converted in to mechanical power of the piston movement kiOwn as indicated power[IP]A -tittlerunount of 1P is used to overcome the frictional losses of the engine known as frictional power [FP and the remaining is delivered as the usemiddotful power output of the engine knownas Brake power[BPJ
PROCEDURE 1 From the specifi9~tiops pf th~ ngine calculate the effective m~imum load that can be applied to themiddotbrake drum at the rated constantspeed
2 Check Fuel supply Cooling water supply and the lubricating oil level
3 Ensure there is no load on the engine start the engine and bring it to the rated speed
-4 Allow cooling water tothe brake drum and load the engine and note down the time taken for 20cc of fuel consumption for different loads 5 At the end of the experiment the engine is stopped by operating the fuel cut offlever
TO FIND THE FRICTIONAL POWER [FP] A curve is drawn between TFC on Y axis and BP on X axis A tangent is drawn to the curve and extended to meet the X axis The negative distance from the origin is FP The FP varies with speed Since the experiment is done at a constant speedFP is constant for all loads
OBSERVATIONS
The following observations are made at each Load (1411234 of maximum load ampFull load)
1 Effective load on the brake drum WI in Kg 2 Spring balance reading W2in Kg 3 Net load =(WI+1 W2) in Kg
Where =weight ofbanger in Kg( 1) 4 Time taken for 20cc of fuel consumption in sec
The following calculations are made from the above set of observations for Each particular load
1 Torque applied on the Engine T = (Wl+I-W2)x981xR Nm WhereR=(brake drwn radius incm+l )XI0-2 Where =Diameter of rope in cm
2 Brake power( BP) = 2n NT --------- KW 60xl000
3 Total fuel consmnption (TFC) = 20 3600 ---- x SP gravity ofdieselx------- kghr t 1000
SPgravity of diese1 = 083
4 Specific fuel consumption( SFC)= TFC - ------ kgkw-hr
BP
5Find out Friction power through graph FP in KW - 6 Indi9~ted power IP ip KW = (BP+FP)
7 Mechanical efficiency BP ---- x 100 IP
8 Heat input by fuel to the engine in one second (HI) TFC
------ x CV in KW 60x 60 Where CV = calorific value of fuel 43000 kjkg
9 Brake thonnal efficiency BP ---- x 100 HI
10 Indicated thennal efficiency IP --- x 100 HI
11 Indicated Mean Effective pressure
IMEP lP x n x 60xK ------------- in KNm2 AxLxN
Where LP inKw n = 2 for 4 stroke Engine n=1 for 2 stroke Engine
K= No of cylinder (A) Area of pistan =1t d24 where d= 8 xl 0-2 I L == Length of stroke =11 x10-2 N = Engine running speed 1500rpm
f
J2BrakeMeariEffective pressure BMEP= BPxnx60xK -------------- in KNm2 AxLxN
Where BP-in Kw
I
The above observations and calculation parameters are Put in a proper Tabular column
TABULAR COLU1v1N
SN OFmL
CONSllMPfJQN IN(Sec)
HAN(ER (WI) IN LQAIO
(Kg)
TFC IN
(KgIht)
llmech
RESULT
The following graphs are drawn
1 BPVs TFC
2 Bp Vs SFC
3 Bp V s Mech e~ciency
4 BpVsBTE
5 BP Vs ITE
-
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
PERFORMANCE TEST ON CONSTANT SPEED ENGINE DETERMINATION OF FRICTION POWER BY PERFORMANCE TEST
AIM To conduct a performance test on a constant speed engine and to find the mechanical
efficiency using negative horse power method
INTRODUCTION The experiment is conducted on a diesel engine of the following specifications
make COMET type vertical Automatic governing loading mechanical brake
brake power 37 KW rated speed 1500 RPM bore 8 cM stroke 11 CM
Radius of the brake drum 1675 cm
The energy supplied to the engine is by way of burning the fuel The thermal energy generated is known as the calorific value of the fuel A part ofmiddot this energy alone get converted in to mechanical power of the piston movement kiOwn as indicated power[IP]A -tittlerunount of 1P is used to overcome the frictional losses of the engine known as frictional power [FP and the remaining is delivered as the usemiddotful power output of the engine knownas Brake power[BPJ
PROCEDURE 1 From the specifi9~tiops pf th~ ngine calculate the effective m~imum load that can be applied to themiddotbrake drum at the rated constantspeed
2 Check Fuel supply Cooling water supply and the lubricating oil level
3 Ensure there is no load on the engine start the engine and bring it to the rated speed
-4 Allow cooling water tothe brake drum and load the engine and note down the time taken for 20cc of fuel consumption for different loads 5 At the end of the experiment the engine is stopped by operating the fuel cut offlever
TO FIND THE FRICTIONAL POWER [FP] A curve is drawn between TFC on Y axis and BP on X axis A tangent is drawn to the curve and extended to meet the X axis The negative distance from the origin is FP The FP varies with speed Since the experiment is done at a constant speedFP is constant for all loads
OBSERVATIONS
The following observations are made at each Load (1411234 of maximum load ampFull load)
1 Effective load on the brake drum WI in Kg 2 Spring balance reading W2in Kg 3 Net load =(WI+1 W2) in Kg
Where =weight ofbanger in Kg( 1) 4 Time taken for 20cc of fuel consumption in sec
The following calculations are made from the above set of observations for Each particular load
1 Torque applied on the Engine T = (Wl+I-W2)x981xR Nm WhereR=(brake drwn radius incm+l )XI0-2 Where =Diameter of rope in cm
2 Brake power( BP) = 2n NT --------- KW 60xl000
3 Total fuel consmnption (TFC) = 20 3600 ---- x SP gravity ofdieselx------- kghr t 1000
SPgravity of diese1 = 083
4 Specific fuel consumption( SFC)= TFC - ------ kgkw-hr
BP
5Find out Friction power through graph FP in KW - 6 Indi9~ted power IP ip KW = (BP+FP)
7 Mechanical efficiency BP ---- x 100 IP
8 Heat input by fuel to the engine in one second (HI) TFC
------ x CV in KW 60x 60 Where CV = calorific value of fuel 43000 kjkg
9 Brake thonnal efficiency BP ---- x 100 HI
10 Indicated thennal efficiency IP --- x 100 HI
11 Indicated Mean Effective pressure
IMEP lP x n x 60xK ------------- in KNm2 AxLxN
Where LP inKw n = 2 for 4 stroke Engine n=1 for 2 stroke Engine
K= No of cylinder (A) Area of pistan =1t d24 where d= 8 xl 0-2 I L == Length of stroke =11 x10-2 N = Engine running speed 1500rpm
f
J2BrakeMeariEffective pressure BMEP= BPxnx60xK -------------- in KNm2 AxLxN
Where BP-in Kw
I
The above observations and calculation parameters are Put in a proper Tabular column
TABULAR COLU1v1N
SN OFmL
CONSllMPfJQN IN(Sec)
HAN(ER (WI) IN LQAIO
(Kg)
TFC IN
(KgIht)
llmech
RESULT
The following graphs are drawn
1 BPVs TFC
2 Bp Vs SFC
3 Bp V s Mech e~ciency
4 BpVsBTE
5 BP Vs ITE
-
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
OBSERVATIONS
The following observations are made at each Load (1411234 of maximum load ampFull load)
1 Effective load on the brake drum WI in Kg 2 Spring balance reading W2in Kg 3 Net load =(WI+1 W2) in Kg
Where =weight ofbanger in Kg( 1) 4 Time taken for 20cc of fuel consumption in sec
The following calculations are made from the above set of observations for Each particular load
1 Torque applied on the Engine T = (Wl+I-W2)x981xR Nm WhereR=(brake drwn radius incm+l )XI0-2 Where =Diameter of rope in cm
2 Brake power( BP) = 2n NT --------- KW 60xl000
3 Total fuel consmnption (TFC) = 20 3600 ---- x SP gravity ofdieselx------- kghr t 1000
SPgravity of diese1 = 083
4 Specific fuel consumption( SFC)= TFC - ------ kgkw-hr
BP
5Find out Friction power through graph FP in KW - 6 Indi9~ted power IP ip KW = (BP+FP)
7 Mechanical efficiency BP ---- x 100 IP
8 Heat input by fuel to the engine in one second (HI) TFC
------ x CV in KW 60x 60 Where CV = calorific value of fuel 43000 kjkg
9 Brake thonnal efficiency BP ---- x 100 HI
10 Indicated thennal efficiency IP --- x 100 HI
11 Indicated Mean Effective pressure
IMEP lP x n x 60xK ------------- in KNm2 AxLxN
Where LP inKw n = 2 for 4 stroke Engine n=1 for 2 stroke Engine
K= No of cylinder (A) Area of pistan =1t d24 where d= 8 xl 0-2 I L == Length of stroke =11 x10-2 N = Engine running speed 1500rpm
f
J2BrakeMeariEffective pressure BMEP= BPxnx60xK -------------- in KNm2 AxLxN
Where BP-in Kw
I
The above observations and calculation parameters are Put in a proper Tabular column
TABULAR COLU1v1N
SN OFmL
CONSllMPfJQN IN(Sec)
HAN(ER (WI) IN LQAIO
(Kg)
TFC IN
(KgIht)
llmech
RESULT
The following graphs are drawn
1 BPVs TFC
2 Bp Vs SFC
3 Bp V s Mech e~ciency
4 BpVsBTE
5 BP Vs ITE
-
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
9 Brake thonnal efficiency BP ---- x 100 HI
10 Indicated thennal efficiency IP --- x 100 HI
11 Indicated Mean Effective pressure
IMEP lP x n x 60xK ------------- in KNm2 AxLxN
Where LP inKw n = 2 for 4 stroke Engine n=1 for 2 stroke Engine
K= No of cylinder (A) Area of pistan =1t d24 where d= 8 xl 0-2 I L == Length of stroke =11 x10-2 N = Engine running speed 1500rpm
f
J2BrakeMeariEffective pressure BMEP= BPxnx60xK -------------- in KNm2 AxLxN
Where BP-in Kw
I
The above observations and calculation parameters are Put in a proper Tabular column
TABULAR COLU1v1N
SN OFmL
CONSllMPfJQN IN(Sec)
HAN(ER (WI) IN LQAIO
(Kg)
TFC IN
(KgIht)
llmech
RESULT
The following graphs are drawn
1 BPVs TFC
2 Bp Vs SFC
3 Bp V s Mech e~ciency
4 BpVsBTE
5 BP Vs ITE
-
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
TFC IN
(KgIht)
llmech
RESULT
The following graphs are drawn
1 BPVs TFC
2 Bp Vs SFC
3 Bp V s Mech e~ciency
4 BpVsBTE
5 BP Vs ITE
-
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
middot
PERFORMANCE TEST ON RECIPROCATING AIR COMPRESSOR
To conduct a test on 2 stage Air compressor and to determine the volumetric eficiency and isothermal efficiency at various delivery pressures
DESCRIPTION Two- stage Air compressor is a reciprocating type( driven by a AcMotor prime mover)
through a belt The test rig consists of a base on which the tank (air reservoir) is mounted The outlet of the air compressor is connected to the reservoir The teWfrature and pressure of the air compressed is indicated by a temperature and pressilie gauge A pressure switch is provided for additional safety A manometer is provided for measuring pressure difference across the orifice The input to the motor is recorded by energy meter
PROCEDURE 1 The outlet valve is closed 2 The manometer connections are checked TJle manometer is filled with water up to the half leveL 3 The compressor is switched on 4 The tank pressure gauge is read for particular pressure and at that noted pressure the outlet valve is opened slowly adjusted so that the pressure is maintained constant
The following readings are note down rpm of the motor and compressor the manometer reading The time for 5 revolutions of the energy meter disc
~ Repeat the experiment for various delivery pres~ures
TABULAR COLUMN
CALCULATIONS
Density of air at RTP pa(RTP) = pa(NTP)273(273+room temp inOc) where pa(NTP) is Density of air at normal temperature and pressure =1293kglm3
Air Head (H) hpw(pa[RTPJ) pw ~ Density ofwate~ =1000kglm3
Theoretical Volume (Vt) (1t4)d2L (N60) d=diameter of the IP cylinder(8751111p)
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
L = stroke length(SOtnm) N = Compressor speed in RPM =500
Actual Volume(Va) = Cd a (2gH)12 Cd = co-efficient ofdischarge(O6) a = Area of the orifice = (1tI4)(00l j2
Volumetric Efficiency (Actual volumelTheoritical volume) 100middot
No of revolutions 3600 OS Actual work input = ----------------------------------shy
Time EMC Energy meter constant(EMC)=75 No of revolutions=5
Isothermal work input =Pa Va loger
Pa = atmospheric pressure in KNm2 (101325) Va = actual air flow into the compressor in in3sec (Actual volume)
Pa +(pgauge ofreservoir09S066)
r ----------------------------------------shy Pa
Pa=Atmospheric pressure in Nm2 Pgauge ofteservoir in kglcm2
Isothermal Efficiency = (Isothermal work Actual work) 100
GR-APHS 1 Delivery pressure vs Isothermal Efficiency
2Delivery pressure vsVolumettic Efficiency - -
bull
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
VALVE TIMING DIAGRAM - 4 STROKE DIESEL ENGINE
INTRODUCTION
The experiment is conducted on a reduced scaled model of a 4 stroke vertical diesel engine The experiment aims to represent di~grammatically the sequence of operations of the inlet valve exhaust valve and the fuel injection with respect to the crank angle of the engine Thus valve timing is the regulation of the points in the thennodynamic cycle of the engine at which valves are set to open and close
The ideal theoretical sequence of operation for a 4 stroke CI engine is as follows
1 Suction Stroke The inlet valve opens and air alone is inducted in to the cylinder as the piston moves
down from the top dead centre (mC) towards the bottom dead centre (BDC) The exhaust valve is kept closed through out the process
2 CompressionStroke The inlet and exhaust valves are kept closed and the pisJon moves up from the BDS
towards the TDC thereby compressing the air according to the compression ratio of the engine Compression ratio (CR) is the ratio of the maximum cylinder volume to the minimum cylinder volume in a tbennodynamic cycle of the engine In Cl engine (eg diesel engine) the compression ratio is in between 121 to 221
3 Expansion stroke or workingstroke or power stroke ~ Both valves remain closed during this stroke The pistoriis at the TDe Fuel ih1ection
in to thecylinder starts at the beginning of the expansion stroke Due to the high compression ratio the temperature at the end of the compression stroke is sufficient to ignite the fuel which comes through the fuel injector
A rapid explosion takes just after the ignition of the fuel Expansion of the hot gases follows pushing the piston down toBDC It is in this stroke that the useful work is obtained from the engine
4 Exhaust stroke The exhaust valve remain open and the inlet valve remain closed in this stroke The
piston moves up from the BDS towards the mc pushing off the expanded hot gases out of the cylinder through the exhaust valve
After the completion of the exhaust stroke the cycle repeats
The energy from the power stroke is stored in the fly wheel which in tum energizes the piston for the other 3 strokes Theoretical valve timing details
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
1 IV0 at TDC during the start of suction stroke 2 IVC at BDC during the start of compression stroke 3 FI at IDC during the start of the expansion stroke 4 EVO at BDC during the start of the exhaust stroke 5 EV C at TDC during the completion of the exhaust stroke
The actual valve timing details are different from the theoretical one for the following reasons 1 ~echanicalfactor
The valves are opened and closed by some mechanisms whose good design induces gradual opening and closing at them 2 Dynamic factor
The air flow IN and the gas flow OUT involves gas dynamic effects which induces a gradual opening and closing ofthevalve~
Typical actual valve timing details of a 4 stroke diesel engine is as follows
1 IV0 15 deg before TDC during the end of the exhaust stroke 2IVC 25 deg after BDC during beginning of the compression stroke 3 FIS 15 deg before TDC during the end of the compression stroke 4 EVO 35 deg before BDC during the end of the power stroke 5EVC 12 deg after TDC during the beginning of the suction stroke
IVO - Inlet Valve OpensshyIVC Inlet Valve Closes EVO - Exhaust Valve Opens EV C - Exhaust V alve Clos~s
FIS - Fuel Injection Starts
--PROCEDURE The flywheel of the rnodel is rotated-till the-piston reachestheBDC The lower most
portion of the flywheel and the corresponding portion o(the base of the model is properly marked with a chalk piece The total length of the circumference of the flywheel outer rim is measured by a thread This length C corresponds to 360 of flywheel rotation The flywheel is rotated till piston reaches TDC and then the rim is marked The flywheel is then taken back to the BDe for t~e suction stroke anqthe point at whi~h the IVC is marked on the rim of the flywheel Similarly the flywheel is rotated through an the 3 remaining strokes and the valve openings closings and fuel injection are properly marked on the flywheel rim The collected details are then depicted through the valve timing diagram
TABULAR COLUMN
Valve bperUngel~~ DIstance AngteCD1Stancel Circumference-of POsiU(lil tYWh~1)~060
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
I
PORT TIMING DIAGRAM OF 2 STROKE PETROL ENGINE
INTRODUCTION The experiment is conducted in a reduced scaled model of a 2 stroke vertical petrol
engine The aim is to represent diagrammatically the sequence of operation of the inlet port exhaust port transfer port and the spark timing with respect to the crank angle of the engme
In 2 stroke engines the thermodynamic cycle is completed in 2 strokes of the piston through one revolution of the crank or flywheel
The ideal theoretical sequence of operation for a 2 stroke SI engine (eg petrol engine of the crank case - scavenger type) is as follows
1 Compression stroke Piston starts moving up from the BDC towards the IDC compressing the charge of
petrol and air in the combUstion chamber During the compression stroke as the piston moves up from BDC the pressure of fresh charge in the crank case decreases and after some further upward movement of the piston the inlet port gets uncovered by the piston
Thus the fresh charge from the carburetor rushes in to the crank case At the end of the compression stroke spark gets produced at the spark plug electrode Thus igniting the charge for an explosion and the consequent expansion of the gases pushing down the piston in the power stroke
II Power stroke Piston travels down from the TDC towards the BDC First the exhaust port gets
uncovermiddot by the piston and the expanded gases pushDUT of the cylinder Consequently the transfer port gets uncovered by the piston and thus fresh charge gets in to the combustion chamber portion of the cylinder
In the power stroke the powerful downward motion of the piston produces the power output from the engine Also the fresh chargemiddotenters the combustion chamber space through
transfer port since the pressure in the crank case increases during the downward motion of the piston
The flywheel of the model is rotated till the piston reaches the BDC The lower most portion of the flywheel and the corresponding portion of the base is properly marked The totallength of the Circumference of the flywheel outer rim is measured as Ie corresponding to 360 degree of flywheel rotation The flywheel is rotated till the piston reaches TDC for compression stroke
The following points at the cycle are marked on the flywheel rim
1 Inlet Port Opens -(IPO)fresh charge enter into the crankcase from carburetor 2 Exhaust Port Closes - (EPC) after the full closing of the exhaust port and transfer port compression of the charge begins 3 Transfer port closes - (TPC) 4 (TDC) - when the reaches TDC spark ignition happens accompanied by the explosion the piston
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
The flywheel is rotated till the piston travels down the TDCtowards the BDC denoting the power stroke
The following points are marked on the flywheel rim
1 Exhaust Port Opens- EPO
2 Inlet Port Closesmiddot IPC
3 Transfer Port Opensmiddot TPO
Fresh charge enters the combustion chamber space due to the pressurizing in the crankcase by the downward motion of the piston
Typical actual port timing details of a 2 stroke engine is as follows 1 EPC - during start of the compression stroke -70 degree After BDC - piston upward motion 2 TPC - 60 degree After BDC - piston upward motion 3 IPO - 130 degree after BDC piston upward motion 4 SI - Spark ignition 20 degree Before mc S TDC - end ofcompression stroke
amp IPCmiddot 50 degree after TDC 7 EPO -70 degree before BDC - expanded gases start pushing out of the cylinder 8 TPO - 60 degree before BDC - fresh ~harge start entering the combustion chamber space
The collected details ate then depicted through proper port timing diagram
TABLUR COLUMN
Port OpenmgnJt~~tng IDisanGe Angle Positiml (em)
Angle = Distance measured 360
Circumference of flywheel
