Morse Test

MORSE TEST # AIM: To study and conduct Morse Test on three-cylinder four-stroke Petrol Engine and to determine: i) Indicated Power of Individual Cylinders ii) Indicated Power of Engine iii)Frictional Power of Engine iv)Mechanical Efficiency # THEORY: Morse Test is applicable to multi-cylinder engines. The engine is run at desired speed and output is noted. Then one of the cylinders is cut out by short circuiting spark plug. Under this condition other cylinders “motor” this cut cylinder. The output is measured by keeping speed constant to original value. The difference in output is measure of the indicated power of cut-out cylinder. Thus for each cylinder indicated power is obtained to find out total indicated power. Let, BP = Brake Power when all cylinders are in working condition. BP1 = Brake Power when first cylinder cut-off. BP2 = Brake Power when second cylinder cut-off. BP3 = Brake Power when third cylinder cut-off. IP = Indicated Power of Engine IP1 = Indicated Power of first cylinder IP2 = Indicated Power of second cylinder IP3 = Indicated Power of third cylinder FP1, FP2, FP3 = Friction power of each cylinder When, All cylinders in working condition, IP = (IP1 + IP2 + IP3) …………………………………………………………………(i) BP = (IP1 + IP2 + IP3) – ( FP1+ FP2 + FP3 ) ……………………………………….….(ii) First Cylinder Cut-off, BP1 = (IP2 + IP3) – ( FP1+ FP2 + FP3 ) ………………………………………………. (iii) Where, ( FP1+ FP2 + FP3 ) in above both eqs.(ii)&(iii) remains almost constant at constant speed. Subtracting Eq.(iii) from Eq.(ii), We get, Indicated Power of first cylinder, IP1 = (BP - BP1) …………………………………………………………………….(iv) Similarly, Indicated Power of second cylinder IP2 = (BP - BP2) ……………………………………………………………………..(v) Indicated Power of third cylinder IP3 = (BP - BP3) …………………………………………………………………….(vi) Putting the values of IP1, IP2, IP3¬ in eq.(i),we get, IP = (BP - BP1) + (BP - BP2) + (BP - BP3) ………………………………….……(vii) Frictional Power, FP = ( IP – BP ) ……………………………………………………………………(viii) Mechanical Efficiency, ?m = (BP / IP) ………………………………………………………………………(ix) # TEST SET-UP:

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Fig.: Experimental Set-up for Morse Test # TEST PROCEDURE: • Ensure cooling water circulation for Eddy current dynamometer, engine and calorimeter. • Start the set up and run the engine at no load for 4-5 minutes. • Gradually increase the load on the engine by dynamometer loading unit. • Increase the engine throttle to any desired position and simultaneously load the engine to obtain desired speed for which frictional power is to be calculated. • Wait for few minutes till steady state is achieved. Note Engine speed and load. • Short the plug of cylinder no.1 by earthing it from Morse test panel. The engine speed shall decrease. Now decrease the load on dynamometer and bring back engine speed to the original. • Wait for steady state (for @ 3 minutes) and note down the reading in observation table. • Gradually decrease the load. # SET- UP SPECIFICATIONS: Engine power : 27.6 kW (37 HP) Engine max speed : 5000 RPM Cylinder bore : 66.5mm Stroke length : 72.0mm Connecting rod length: 114 mm Compression ratio : 9.2:1 Stoke type : Four No. of cylinders : Three Speed type : Variable Cooling type : Water Dynamometer type : Eddy current Dynamometer arm length (m) : 210 mm Indicator used type : Cylinder pressure Interface type used : PCI-1050 Calorimeter used : Pipe in pipe

# OBSERVATION TABLE: Cut off cylinder number Speed (RPM) Load (Kg) 1 2000 12.5 2 2000 12.1 3 2000 12.8 All working 2000 20 # CALCULATIONS: # Brake Power Calculations:

All cylinders in working condition,

First Cylinder cut-off,

Second Cylinder cut-off,

Third Cylinder cut-off,

# Indicated Power Calculations: Indicated Power of first cylinder,

Indicated Power of second cylinder, Indicated Power of third cylinder, # Indicated Power of Engine, # Frictional Power of Engine, # Mechanical Efficiency,

RESULTS: i) Indicated Piower of Engine = 9.76 kW ii) Frictional Power of Engine = 1.13 kW iii) Mechanical Efficiency of Engine = 88.42%