8/19/2019 Morse Test Final
1/31
MORSE TEST
Introduction: - The basic task in the design and development of
I.C.Engines is to reduce the cost of production and improve the
efficiency and power output. In order to achieve the above task, the
engineer has to compare the engine developed by him with other
engines in terms of its output and efficiency. Hence he has to test the
engine and make measurements of relevant parameters that reflect the
performance of the engine. In general the nature and number of tests
to be carried out depend on a large number of factors. In this chapter
only certain basic as well as important measurements and tests are
described.
Important Performance Parameters of I.C.Engines:- The
important performance parameters of I.C. engines are as follows:
Friction Power,
Indicated Power,
Brake Power,
Specific Fuel Consumption,
8/19/2019 Morse Test Final
2/31
Air – Fuel ratio
Thermal Efficiency
Mechanical Efficiency,
Volumetric Efficiency,
Exhaust gas emissions,
Noise
1.3. Measurement of Performance Parameters in a Laboratory
1.3.1. Measurement of Friction Power:- Friction power includes the
frictional losses and the pumping losses. During suction and exhaust
strokes the piston must move against a gaseous pressure and power
required to do this is called the “pumping losses”. The
friction loss is made up of the energy loss due to friction
between the piston and cylinder walls, piston rings and
cylinder walls, and between the crank shaft and camshaft and
their bearings, as well as by the loss incurred by driving the
essential accessories, such as water pump, ignition unit etc.
8/19/2019 Morse Test Final
3/31
Following methods are used in the laboratory to measure
friction
power:
Willan’s line method;
From the measurement of indicated power and brake power;
Motoring test;
Retardation test;
Morse Test.
1.3.1.2.From the Measurement of Indicated Power and Brake
Power:- This is an ideal method by which friction power is obtained
by computing the difference between the indicated power and brake
power. The indicated power is obtained from an indicator diagramand brake power is obtained by a brake dynamometer. This method
requires elaborate equipment to obtain accurate indicator diagrams at
high speeds.
8/19/2019 Morse Test Final
4/31
1.3.1.3.Morse Test:- This method can be used only for multi –
cylinder IC engines. The Morse test consists of obtaining indicated
power of the engine without any elaborate equipment. The test
consists of making, in turn, each cylinder of the engine inoperativeand noting the reduction in brake power developed. In a petrol engine
(gasoline engine), each cylinder is rendered inoperative by
“shorting” the spark plug of the cylinder to be made inoperative. In a
Diesel engine, a particular cylinder is made inoperative by cutting off
the supply of fuel. It is assumed that pumping and friction are the
same when the cylinder is inoperative as well as during firing.
In this test, the engine is first run at the required speed and the brake
power is measured. Next, one cylinder is cut off by short circuiting
the spark plug if it is a petrol engine or by cutting of the fuel supply if
it is a diesel engine. Since one of the cylinders is cut of from
producing power, the speed of the engine will change. The engine
speed is brought to its original value by reducing the load on the
engine. This will ensure that the frictional power is the same.
If there are k cylinders, then
Total indicated power
when all the cylinders are working = ip1 + ip2 + ip3 + …………...+ ipk
= ip j
j = 1
We can write ip j = Bt + Ft ………………………………………..(1)
8/19/2019 Morse Test Final
5/31
8/19/2019 Morse Test Final
6/31
Similarly we can find the indicated power of all the cylinders, viz.,
ip2, ip3, …..ipk. Then the total indicated power is calculated as
(ip)total = ip j ……………………………………….(4)
j = 1
The frictional power of the engine is therefore given by
Ft = (ip)total – Bt ……………………………………(5)
The procedure is illustrated by some examples worked out at the endof the chapter.
8/19/2019 Morse Test Final
7/31
NEED OF MORSE TEST
The i.p. and the mechanical efficiency of a multi-cylinder auto engine
is found out in a veryshort time by this test. During the test the engine is run at a constant
speed and at same throttle
opening. First the b.p. of the engine with all cylinders operative is
measured by means of
dynamometer. Next, the b.p. of the engine is measured with each
cylinder rendered inoperative
one by one by shorting the spark plug in case of petrol engine or by
cutting off the fuel supply
in case of diesel engine.
hen any cylinder is rendered inoperative, the speed abruptly goes
down. !efore taking
any reading, the initial speed must be restored by ad"usting the load.
#t is assumed that the f.p. of the inoperative cylinder remains the same
as it were when the
cylinder was operative. $onsidering the case of a %-cylinder engine,
8/19/2019 Morse Test Final
8/31
8/19/2019 Morse Test Final
9/31
6 MEASUREMENT OF I.P OF MULTI-CYLINDER ENGINE (MORSE
TEST)
This method is used in multi-cylinder engines to measure I.P with out the use of
indicator. The BP of the engine is measured by cutting off each cylinder in turn.
If the engine consists of 4-cylinders, then the BP of the engine should be
measured four times cutting each cylinder turn by turn. This is applicable to
petrol as well as for diesel engines. The cylinder of a petrol engine is made
inoperative by “shorting” the spark plug whereas in case of diesel engine, fuel
supply is cut-off to the required cylinder.
If there are ‘n’ cylinders in an engine and all are working, then (B.P)n = (I.P)n –
(F.P)n
Where F.P is the frictional power per cylinder.
8/19/2019 Morse Test Final
10/31
If one cylinder is inoperative then the power developed by that cylinder (IP) is
lost and the speed of the engine will fall as the load on the engine remains the
same. The engine speed can be resorted to its original value by reducing theload on the engine by keeping throttle position same. This is necessary to
maintain the FP constant, because it is assumed that the FP is independent of
load and depends only on speed of the engine.
When cylinder “1” is cut off; then
(B.P)n – 1
= (I.P)n – 1
– (F.P)n …..(12)
By subtracting Eq. (23.7) from Eq.(23.6), we obtain the IP of the cylinder which
is not firing i.e., (B.P)n – (B.P)n-1 = (IP)n – (IP)n-1 = I.P1
Similarly IP of all other cylinders can be measured one by one then the sum of
IPs of all cylinders will be the total IP of the engine.
This method of obtaining IP of the multicylinder engine is known as ‘Morse
Test’.
Illustrative examples:
8/19/2019 Morse Test Final
11/31
8/19/2019 Morse Test Final
12/31
20.9
(ii) mech = -------------
=
---------=0.833=83.3 %
(ip)total
25.1
60,000 Bt
60,000 x 20.9
(iii) bmep = ---------------
=--------------------------------------------------
L A n K
0.09x(/4)x 0.0752 x (3000 / 2) x 4
= 5.25 x 105 N / m
2 = 5.25 bar.
MORSE TEST ON MULTI CYLINDER
PETROL ENGINE
Ex.No. : Date:
8/19/2019 Morse Test Final
13/31
Aim :
To conduct morse test on given multi cylinder petrol engine in order to
determine the indicated power developed in the each cylinder of the engine and
to determine the mechanical efficiency.
Apparatus Required :
*ulti cylinder petrol engine with ignition cut off arrangement
+oading arrangements
Tachometer
Theory and Description :
For slow speed engine the indicated power is directly calculated from the
indicator diagram. !ut in modern high speed engines , it is difficult to obtain
accurate indicator diagram due to inertia forces , and therefore , this method
cannot be applied . #n such cases the morse test can be used to measure the
indicated power and mechanical efficiency of multi cylinder engines . Theengines test is carried out as follows . The engine is run at maximum load at
certain speed . The !. is then measured when all cylinders are working .
Then one cylinder is made in operative by cutting off the ignition to that
cylinder . s a result of this the speed of the engine will decrease . Therefore ,
the load on the engine is reduced so that the engine speed is restored to its initial
value . The assumption made on the test is that frictional power is depends onthe speed and not upon the load on the engine .
8/19/2019 Morse Test Final
14/31
Definitions :
Break poer : !B"#
The useful power available at the crank shaft of the engine is called brake power
of the engine . The brake power of the engine are determined by
.
/ope brake dynamometer.
T 0 /e
0 net load
/e
0 effective radius of the brake drum
1.
rony brake dynamometer
T 0 +
8/19/2019 Morse Test Final
15/31
0 +oad
+
0 Distance at which the load is applied
$%ser&ation and Ta%u'ation :
'(
!rake power !. 0........... 2
'1(
/ated 3peed N 0.........../pm
'4(
Type of loading 5 0...........
8/19/2019 Morse Test Final
16/31
'%(
/adius of brake drum 5 / 0........... 6m7
'8(
/adius of /ope r 0 0........... 6m7
'9(
Number of cylinders 0 %
8/19/2019 Morse Test Final
17/31
( No
)onditions
*oadin+
(peed
B" ,-W
W/ k+
W0
W/ 1 W0
Net 'oad
Rpm
k+
k+
8/19/2019 Morse Test Final
18/31
W in ,N
/
A'' cy'inders are
orkin+
0
2irst
cy'inder
8/19/2019 Morse Test Final
19/31
as cut off and
remainin+ are in
8/19/2019 Morse Test Final
20/31
orkin+
3
(econd
cy'inder
as cut off and
8/19/2019 Morse Test Final
21/31
remainin+ are in
orkin+
4
Third
cy'inder
8/19/2019 Morse Test Final
22/31
as cut off and
remainin+ are in
8/19/2019 Morse Test Final
23/31
orkin+
5
2ourth
cy'inder
as cut off and
8/19/2019 Morse Test Final
24/31
remainin+ are in
orkin+
Note 5 The speed should be same for all readings
4. :ydraulic dynamometer !. 0 N
8/19/2019 Morse Test Final
25/31
$
0 +oad
N 0 3peed in /*
$ 0 Dynamometer constant
%. ;lectrical dynamometer
6ndicated poer : ! 6 " #
The power actually developed inside the engine cylinder due to the combustion
of the fuel are called indicated power .
# 0 F < ! & F 0 Frictional power
2rictiona' poer !2"# :
The power loss due to friction between the moving parts are called as frictional
power .
Mechanica' efficiency : !ηmech #
#t is defined as the ratio of !rake power to indicated power .
8/19/2019 Morse Test Final
26/31
8/19/2019 Morse Test Final
27/31
0
9= x === x 1.8
0
1 ? x 1===
T
0
./e
3ay /e 0 =.%m
...
0
T>>
0
%@.1N
/e
8/19/2019 Morse Test Final
28/31
=.%
B
8= N
8/19/2019 Morse Test Final
29/31
max 5 load that can be given to the engine was
C8
w 0
C8 x 8=
0 1.8N
==
max
0
net load 0
1.8 0
.18kg
=
8/19/2019 Morse Test Final
30/31
$heck the engine for fuel availability, lubricant and cooling water
connections .
/elease the load completely on the engine and start the engine in no loadconditions and allow the engine to run for few minutes to attain the rated
speed.
pply the load and increase the load upto maximum load. 'll four
cylinders should be in working ( . Now note the load on the engine and
speed of the engine say the speed is
6N7 rpm
$ut-off the ignition of first cylinder, Now the speed of engine decreased .
/educe the load on the engine and bring the speed of the engine to 6N7 rpm.
Now note the load on the engine.
!ring the all four cylinders are in working conditions and cut off the 1nd , 4rd
and %th
cylinder in turn and ad"ust the load to maintain same 6N7 rpm and
note the load .
Resu't:
*orse test was conducted on given petrol engine and indicated power
developed in each cylinder are determined and mechanical efficiency are
also determined .
8/19/2019 Morse Test Final
31/31
Top Related