Experiment No. – 5
Name of the Experiment: –
Morse test on the four cylinder four stroke petrol engine with hydro dynamometer.
Objective:
To determine the IHP, BHP, specific fuel consumption, mechanical efficiency, and brake thermal efficiency under variable load and to draw the performance curve.
Apparatus Required:
- Morse test petrol engine test rig.
- Spring balance [Least count: 0.25]
- Speedometer [Range:1500-3000]
- Fuel measuring device
- Stop watch
- Thermometer(4)
- Water volume measuring device.
Engine specification:
| Sl. No. | Particulars | Details | ||
| 1 | Basic Thermodynamic Cycle | Otto cycle | ||
| 2 | Number of strokes per cycle | Four | ||
| 3 | RPM Of Engine( Rated) | 2500 | ||
| 4 | Number of Cylinders And its Position | Four, vertical | ||
| 5 | Bore Of Cylinder (D) | 68 mm | ||
| 6 | Stroke Length(L) | 75 mm | ||
| 7 | Fuel Used | petrol | ||
| 8 | Specific Gravity of Fuel (S) | 0.83 | ||
| 9 | Calorific Value of Fuel (Q) | 44000 kj/kg | ||
| 10 | Method of Ignition | Spark Ignition | ||
| 11 | Compression ratio | 7.8 : 1 | ||
test rig of morse test petrol engineFormula used:
\[\color\green{(i)\; B.H.P\; =\;}\]
\[\color\red{\dfrac{2*\pi*N*T}{4500}\;=\;\dfrac{2*\pi*S*R*N}{4500}}\]
\[\color\green{Where,\; N\;= speed \;in\; RPM}\]
\[\color\green{S\;= \;spring \;balance \;reading}\]
\[\color\green{R\;=\;320\; mm}\]
\[\color\green{(ii)\;Indicated \;power\;}\]
\[\color\red{(IP)_1 \;=\; (BP)_{all} – (BP)_1}\]
\[\color\red{(IP)_2 \;= \;(BP)_{all} – (BP)_2}\]
\[\color\red{(IP)_3\; = \;(BP)_{all} – (BP)_3}\]
\[\color\red{(IP)_4 \;= \;(BP)_{all} – (BP)_4}\]
\[\color\green{(iii)\; Indicated \;power}\]
\[\color\red{(IP)_{all} \;= \;(IP)_1 + (IP)_2 + (IP)_3 + (IP)_4}\]
\[\color\green{(iv)\;Friction\; power}\]
\[\color\red{(FP)_{all}\; = \;(IP)_{all} – (BP)_{all}}\]
\[\color\green{(v)\;B.S.F.C\; = \;Fuel\; consumption\;}\]
\[\color\green{ per\; B.H.P\; per \;hour}\]
\[\color\red{=\;\dfrac{50*l*3600}{(t*B.H.P*1000}}\color\black{ kg/hp/hr}\]
\[\color\green{Where,\; t\; is\; the \;time\; taken \;to \;consume\;}\]
\[\color\green{ 50 \;ml\; of\; diesel\; in\; seconds\; and\;}\]
\[\color\green{L \;is\; density\; of\; fuel}\]
\[\color\green{Brake\; thermal\; Efficiency \; = \;}\]
\[\color\red{\dfrac{B.H.P*4500}{W*Q*J} *100\; }\color\black{\%}\]
\[\color\green{Where\; 4500 \;kg .m/min\; is\; the\; }\]
\[\color\green{equivalent\; of\; one\; H.P}\]
\[\color\green{W\;= \;weight\; of\; fuel\; supplied\; in \;kg/min}\]
\[\color\green{Q\;=\; calorific\; value\; of\; fuel \;in\; kcal/kg}\]
\[\color\green{J\;= \;mechanical\; equivalent\; of\; heat}\]
Procedure:
- First of all different parts of the engine should be lubricated so that the effect of friction can be reduced and in the pump the level of lubricating should be checked prior to starting the machine.
- The level of oil storage tank should be checked and the lock with fuel line should be removed.
- Ensure no load condition.
- The engine is started and allowed to run on idle speed for a few minutes.
- The load acting on the engine when the entire cylinder is working is notes at constant speed of 2500 rpm.
- By cutting of one cylinder and adjusting the engine to run at 2500 rpm by adjusting the load only.
- Adjust the load by the hydro- dynamometer.
- Then the load acting on the remaining there cylinders is noted from the hydraulic dynamometer.
- Note down all the temperature T1, T2,T3 and T4.
- Also note the water flow outlet from the engine and the time for the fuel consumption.
- Stopping of engine is done after removing load and then the supply of fuel is closed.
Observation table:
| Cylinder Cut-off No. | spring Load (kg) |  t  (sec) | Temperature (oC) | Water outlet flow from engine ( * 1.9 lt) | Water from calorimeter (lt) | |||
| T1Â (oC) | T2Â (oC) | T3Â (oC) | T4 (oC) | |||||
| – | 0 | 80 | 53 | 38 | 120 | 28 | 20 | 2.5 |
| – | 8 | 56 | 109 | 56 | 160 | 28 | 14 | .7 |
| 1 | 6 | 27 | 110 | 54 | 192 | 275 | 14 | .6 |
| 2 | 6.5 | 37 | 110 | 51 | 201 | 27 | 9 | .8 |
| 3 | 7.4 | 44 | 110 | 46 | 220 | 26 | 16.5 | 1.2 |
| 4 | 7.8 | 52.5 | 110 | 43 | 230 | 26.8 | 13 | 1.35 |
Here t = time for the consumption of the 25 ml of petrol in sec
                       T1 = exhaust gas temperature after calorimeter
                       T2 = water outlet temperature after calorimeter
                       T3 = exhaust gas temperature
                       T4 = water outlet temperature from engine
Sample calculation:
\[\color\green{(a)\; Brake\; horse\; power\;=}\]
\[\color\red{2*\pi*N*T}{4500}\;=\;\dfrac{2*\pi*S*R*N}{4500}\]
\[\color\green{Where\; N\;= \;speed\; in\; RPM}\]
\[\color\green{S\;= \;spring\; balance\; reading}\]
\[\color\red{R\;=\;320\; mm\; = \;.32 \;m}\]
\[\color\red{(BP)_{all}\;=\; \dfrac{2*\pi*8*0.32*2500}{4500 }\;=\;8.93\; HP}\]
\[\color\red{(BP)_1\;= \;\dfrac{2*\pi*6*0.32*2500}{4500}\;=\;6.70 \;HP}\]
\[\color\red{(BP)_2\;= \;\dfrac{2*\pi*6.5*0.32*2500}{4500} \;=\;7.26\;HP}\]
\[\color\red{(BP)_3\;=\; \dfrac{2*\pi*7.4*0.32*2500}{4500} \;=\;8.26 \;HP}\]
\[\color\red{(BP)_4\;=\; \dfrac{2Ï€*7.8*0.32*2500}{4500}\;=\;8.71\; HP}\]
\[\color\red{(IP)_1 \;=\; 8.93-6.70\;=\;2.23}\]
\[\color\red{(IP)_2 \;= \;8.93-7.26\;=\;1.67}\]
\[\color\red{(IP)_3 \;= \;8.93-8.26\;=\;0.67}\]
\[\color\red{(IP)_4 \;= \;8.93-8.71\;=\;0.22}\]
Conclusion: –
To be written by student.