first the the power developed by all the cylinders together is determined experimentally.
Then the power of the individual cylinders are determined by cutting off the power supply to the spark plug of the cylinder under test.
then the power developed by the engine with the remaining cylinders is determined experimentally and this value is subtracted from the first value, and this gives you the power developed in the cylinder, whose spark plug was cut off.
similarly this test is carried out on all the cylinders of the engine individually.
Now what i wanted to know is that when there is no production of the electric spark in a cylinder, then what happens to the fuel in that cylinder ?
here new question arises in diesel engine there is no spark plug it burns by compression thn the fuel is burnt by compression and the temp. of engine like wise in ic engine, fuel in that cylinder can be semi burnt by some compression and temperature or somewhat
I am not so sure about it, but i think the morse test is only for petrol engines (spark-ignition engines).
As if i din't know that.LIRILIn Diesel engine the fuel supply in particular cylinder is cut off. Whereas in Petrol engine the spark plug in shut off.
In (SI + DI) engines, we have the option of cutting the fuel injector AND the spark signal, and this might be more logical an option since it will save fuel.
P.S: The Morse test is for both petrol and diesel engines.
When fuel is cutoff to a particular cylinder than we get compression pressure instead of peak pressure.
In SI engines, no partial combustion takes places because octane rating of fuel is high and compression ratio is less. So fuel mixture won't auto ignite. And if partial combustion (fast rate of oxidation) happens then it will auto ignites complete mixture then knocking occurs which means there is some other problem with engine. Pressure developed without spark is called motoring pressure which may be of order 5-10bar and, with spark cylinder pressure can go upto 100bar or beyond depending on cylinder displacement.
During cylinder motoring, unburned fuel can vaporise or go under slow oxidation which doesn't account for significant pressure increase. So fuel comes out of exhuast valve in vapor form thus increasing hydrocarbon emission any slightly CO gas too.
The purpose of the Morse test is to figure out the Indicated Power of SI and CI engines. The test suggests making each of the cylinders inoperative one by one. For example, if you are working with a Diesel engine, you will have to halt the diesel from entering the cylinder.
If you are working with a petrol engine, you could control or short the spark plug, which is responsible for the blasts inside the cylinder.
When the cylinder is not operating (all of a sudden), the speed of the engine goes down. Before the readings are noted, the speed of the engine needs to be restored - which can be done by adjusting the load.
Following would be the calculation for 4-cylinder engine -
B = bp of the engine with all cylinders operative
B1 = bp of engine with cylinder 1 inoperative
B2 = bp of engine with cylinder 2 inoperative
B3 = bp of engine with cylinder 3 inoperative
B4 = bp of engine with cylinder 4 inoperative
l1,l2,l3 and l4 = ip of engine 1,2,3,4 respectively
F1,F2,F3,F4 = fp of cylinders 1,2,3,4 respectively
B = (I1-F1) + (I2-F2) + (I3-F3) + (I4-F4) = (I1+I2+I3+I4) - (F1+F2+F3+F4).
Now for B1, you'll have to take out "I1" will be eliminated from the equation.
Hence B1 = (I3+I3+I4) - (F1+F2+F3+F4)..
Some of the power is lost because of the friction of the piston.
Total IP of engine = I1+I2+I3+I4 = I
Mechanical efficiency = B/I.
@Ankita Katdare · Apr 3, 2015
@Ankita Katdare · Aug 2, 2015
@Ambarish Ganesh · May 21, 2013