Morse Test

 Morse Test

-The Morse test is applicable only to multicylinder engines.

-In this test, the engine is first run at the required speed and the output is measured.

-Then, one cylinder is cut out by short circuiting the spark plug or by disconnecting the injector as the case may be.

-Under this condition all other cylinders „motor‟ this cut-out cylinder.

-The output is measured by keeping the speed constant at its original value.

-The difference in the outputs is a measure of the indicated horse power of the cut-out cylinder.

-Thus, for each cylinder the ip is obtained and is added together to find the total ip of the engine.

-This method though gives reasonably accurate results and is liable to errors due to changes in mixture distribution and other conditions by cutting-out one cylinder. In gasoline engines, where there is a common manifold for two or more cylinders the mixture distribution as well as the volumetric efficiency both change. Again, almost all engines have a common exhaust manifold for all cylinders and cutting out of one cylinder may greatly affect the pulsations in exhaust system which may significantly change the engine performance by imposing different back pressures.

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