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Load test on petrol engine with eddy current dynamometer
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LOAD TEST ON SINGLE CYLINDER, 4-S PETROL ENGINE WITH EDDY CURRENT DYNAMOMETER
AIM
To conduct load test on single cylinder, 4 stroke petrol engine with eddy current dynamometer and to plot the following constant speed characteristics curves.
1. Specific fuel consumption (SFC) vs Brake Power
2. Mechanical efficiency () vs Brake Power
3. Break thermal efficiency() vs Brake Power
4. Indicated thermal efficiency() vs Brake Power
5. Volumetric efficiency() vs Brake Power
6. Brake Mean effective pressure BMEP vs Brake Power
SPECIFICATIONS
BHP : 2.5HP
Speed,N : 3000rpm
No of cylinders : 1
Bore : 70mm
Stroke : 66.7mm
Orifice diameter : 20mm
Arm length of dynamometer: 150mm
Calorific Value of petrol : 43534 kJ/Kg
PRECAUTIONS
1. Check the lubricating oil and fuel levels and top up if necessary.
2. Open the engine cooling water inlet and outlet valves.
3. Engine should be started and stopped with no load.
THEORY
1. Output power or brake power, BP= (2NT/60) Torque T= WRg
Where N = speed in rpm
W = Eddy Current dynamometer reading in kg
g = 9.81 m/s
R = arm length of dynamometer
2. TotalFuelConsumption =
!"/$%&
Where v = volume of fuel consumption in m3 for time tm sec, '%($)*+,-.%*/,0 = 725!"/43
(1) Specific fuel consumption
6 =7. .
!"/!9$%&
(2) Indicated Power, I.P = B.P + F.P Where
F.P - is the Frictional Power of the engine taken as 1/3rd of rated B.P (5) Mechanical efficiency,
=7.. 100
= ?!9
Calorific value (? ) of petrol = 43534 kJ/kg. (4) Brake thermal efficiency,
=7. . 100
)/>%
(5) Indicated thermal efficiency,
=
%
(6) Volumetric efficiency @ABC = @D
D ABC
Hw = Diff in manometer reading (h1-h2) , D = 4E(,4%*/)&-0F)GG%($)*+
(a) Actual volume of air taken in, ?AHIA = JEK2"@ABC 4L/$%& ( where a= area of orifice)
(b) Theoretical volume ?MNCNBHA =
OPQRS
!. ((DU
VNH) k= for 4 stroke engine, and
k= 1 for 2 stroke engine n = no of cylinders Volumetric efficiency, (),
=?AHIA
?MNCNBHA
7. Brake Mean effective pressure (BMEP) = BMEP = CAYNZ[NC
\[N]IDN]NCVNH^JBN._`abcdb`efgh kN/m2
PROCEDURE
Before starting the engine, calculate the maximum load (maximum current) that can be applied on engine by making use of the power equation. Start the engine at no load condition by cranking after switching on the fuel supply. Allow the engine to run for 5 minutes to get heated up. Measure the no load fuel consumption for a particular period of time. Apply the load on the engine by varying current to eddy current dynamometer. Note the spring dial reading (kg). Adjust the speed to the rated RPM by accelerator knob. The time taken for v cc fuel consumption is noted. manometer reading is also noted.. Repeat the experiment up to maximum load. Then load is brought to zero and engine is stopped by switching off the ignition key.
CALCULATIONS:
CHARACTERISTIC CURVES
RESULT: INFERENCE: -------------------------------------------------------------------
TABULAR COLUMN
SI
N
O
Load(W)
Manometric
reading
Time taken for
10ml fuel
consumption
h1 h2 hm=
h1-
h2
Unit
Hair Vact BP BMEP TFC SFC IP Power
input
_iO
kw kg/s kg/kwh kw kw % % % %
LOAD TEST ON TWIN CYLINDER 4 STROKE DIESEL ENGINE (USHA)
(with electrical loading system) AIM:
To conduct load test (Constant speed characteristics) on Twin cylinder 4S Diesel Engine with electrical loading system and to plot the following Characteristic Curves.
1. Brake power (B.P) Vs T.F.C (total fuel consumption) 2. B.P Vs S.F.C (Specific fuel consumption) 3. B.P Vs M.E (Mechanical efficiency) 4. B.P Vs B.T.E (brake thermal efficiency) 5. B.P Vs I.T.E (indicated thermal efficiency) 6. B.P. vs. volumetric efficiency 7. Brake Mean effective pressure BMEP vs Brake Power 8. Indicated Mean effective pressure IMEP vs Brake Power
SPECIFICATIONS:
Engine make: USHA
B.H.P = 10H.P
R.P.M = 1500
No. of cylinders = 2
Compression ratio = 17.5:1
Bore =87.5mm
Stroke = 110mm
Efficiency of Generator = 75%
Orifice Diameter =20 mm
J = 0.62
PRECAUTIONS
1. Fuel and lubricating oil are checked and if needed they are to be supplied. 2. Cooling water inlet and outlet for engine should be opened. 3. Engine should be started and stopped with no load. 4. De-compression liver should be engaged before cranking.
THEORY:
(1) Output Power or Brake Power 7. . = _
kN^NCACll (Watts)
V = voltage in Volts
I = Current in Amperes
(2) Total fuel consumption =
m*D
!"/$%&
Where v = volume of fuel consumption in m3 for time tm, = 826.5!"/43
(3) Specific fuel consumption 6 =
7. .
!"/!9$%&
(4) Indicated Power, I.P = B.P + F.P Where
F.P is the Frictional Power obtained from the characteristic plot (TFC Vs B.P)-Willanes line method.
(5) Mechanical efficiency,
=7. . 100
(5) Input Power (Heat energy Input), )/> = ?!9
Calorific value (? ) of diesel = 46057kJ/kg.
(6) Brake thermal efficiency, =
7. . 100)/>
%
(7) Indicated thermal efficiency, =
%
(8) Volumetric efficiency @ABC = @[
[ ABC
Hw = Manometer reading (h1-h2)
(a) Actual volume of air taken in,
?AHIA = JEK2"@ABC4L/$%& ( where a= area of orifice)
(b) Theoretical volume
?MNCNBHA =OPQRS
!. ((DU
VNH) k= for 4 stroke engine, 1 for 2 stroke engine
n = no of cylinders
Volumetric efficiency, (),
=?AHIA
?MNCNBHA
9. Brake Mean effective pressure (BMEP) = BMEP = CAYNZ[NC
\[N]IDN]NCVNH^JBN._`abcdb`efgh kN/m2
10. Indicated Mean effective pressure (IMEP) = IMEP = ^JBHANJZ[NC
\[N]IDN]NCVNH^JBN._`abcdb`efgh kN/m2
PROCEDURE
Before starting the engine maximum load that can be applied on the engine is calculated using the power equation.
Start the engine at no load condition. Fuel supply is switched on and the decompression lever is engaged. The engine is started by manual cranking. Allow the engine to run for 5 minutes to get heated up. Measure the time taken for v c.c of fuel consumption under no load condition. Now the loading is carried out (electrical resistance loading) by using the selector knob for the required current (load) and time for v cc fuel consumption is noted. The level difference in the water manometer is also noted for each load. Repeat the experiment up to maximum load. Then the engine is stopped by cutting the fuel supply.
CALCULATIONS:
CHARACTERISTIC CURVES
RESULT:
INFERENCE: