Four stroke four cylinder diesel engine with electrical dynamometer.

Experiment No. : 1

Name of The Experiment: –

Four stroke four cylinder diesel engine with electrical dynamometer.

Objective: –

  • To study various components of engine.
  • To perform constant speed performance test on a Four-Stroke four-Cylinder Diesel Engine.

Apparatus Required: –

  • Four-Stroke  four-Cylinder (Constant Speed) Diesel Engine Test Rig.
  • Stop Watch
  • Speedometer

Theory: –

 A heat engine is a device which converts chemical energy of a fuel oil into thermal energy. In engines these energy is converted into useful mechanical work.

Under some circumstances (i.e. Electric Generator) C.I. Engines are required to run at constant speed, for this purpose the test is to be performed at constant speed and the load is varied from zero to maximum. When load on the engine increases its speed decreases. Accordingly the fuel supply is adjusted to keep the engine speed constant. Corresponding to each load setting, dynamometer readings and fuel consumption rate are measured. The BP, BSFC, BMEP, A/F, and Mechanical Efficiency are calculated from measured data and plotted against the load.

Procedure: –

  1. Before starting the engine check the fuel supply, lubrication oil, and availability of cooling water in calorimeter and the engine jacket.
  2. Set the dynamometer to zero loads.
  3. Start the engine and measure the speed of the engine with the speedometer.
  4. Run the engine till it attains the working temperature and steady state condition.
  5. Measure the time for the fuel consumption of 50cc.
  6. Measure the water flow rate through engine and the calorimeter.
  • Take the reading of the manometer and temperature indicator.
4-stroke four cylinder diesel engine.

Observation: –

1Engine Speed, (N) 2000  rpm
2No. of Cylinders (n) 4
3Calorific Value of Fuel, (C.V.) 42,500    KJ/Kg
4Gas Constant (R)0.287  KJ/Kg. K
5Ambient Temperature20 oC.
6Atmospheric Pressure (Pa)1.01325  bar
7Orifice Diameter (do)32 x 10-3   m
8Co-efficient of Discharge (Cd)0.62
9Specific Gravity of fuel (ρfuel)0.76
10Density of Water (ρwater) 1,000  Kg/m3
11Density of air (ρair)1.207Kg/m3
12Brake Drum Diameter (D)181.5 x 10-3m
13Specific Heat of Exhaust Gas1.0   Kj/Kg.K

Table: –

Sl. No.T1 oC   T2 oCT3 oCT4 oCT5 oCT6 oC
125301191241964

T1  = Temp. of water inlet to calorimeter.

T2  = Temp of water outlet from calorimeter.

T3  = Temp. of exhaust gases inlet to calorimeter.

T4  = Temp. of exhaust gases outlet.

T5  = Ambient temp.

T6 = Water outlet temp. from engine.

Measurement of cooling water : –

Water out from calorimeter            =   2300 ml

Water out from engine jacket         =    2550 ml

Water flow rate (engine jacket )     = 3 kg /s

Water flow rate (calorimeter )         = 3 kg/s

Time taken for consumption of 50ml fuel = 57 sec.

Calculation: –

\[\color\green{1. \;Brake\;Power\;(BP)}=\color\red{\dfrac{2*\pi*N*T}{60000}\;\;}\color\black{KW}\] \[\color\red{=\dfrac{2*\pi*2000*T}{60000}}\] \[\color\red{=0.209T\;\;}\color\black{KW}\] \[\;\] \[\;\] \[\;\] \[\color\green{2. \; Total\;fuel\;consumption =}\] \[\color\red{\dfrac{50 ml \;*\; 10^{ -6}\;*\; ρ_{Fuel}}{t}\;\;}\color\black{Kg/Sec.}\] \[\color\red{=\dfrac{50*10^{ -3} *0.76}{57} = 0.667 *10^{ -3}\;\; }\color\black{kg/sec}\] \[\;\] \[\;\] \[\;\] \[\color\green{3. \;Brake\; specific\; fuel\; consumption \;= }\] \[\color\red{\dfrac{Total\; fuel\; consumption\; *3600}{ BP}\;\; }\color\black{kg/kWhr}\] \[\color\red{=\; \dfrac{0.667 *10^{ -3} *3600}{0.209T}}\] \[\color\red{=11.49\;\;}\color\black{ kg/kWhr}\] \[\;\] \[\;\] \[\;\] \[\color\green{4.\; Brake \;thermal\; efficiency\; =}\] \[\color\red{\dfrac{BP}{(total\; fuel\; consumption\; * CV )}}\] \[\color\red{ =\dfrac{ 0.209T}{( 0.667 *10^{ -3} *42500)}}\] \[\color\red{ = 0.74 T }\color\black{\%}\] \[\;\] \[\;\] \[\;\]
\[\color\green{5.\;Air\; fuel\; Ratio\;=}\] \[\color\red{\dfrac{mass\; rate\; of\; air\; consumed}{mass\; rate\; of\; fuel\; consumed}}\] \[\;\] \[\;\] \[\color\red{Mass\; rate\; of\; air\; =\; Q * ρair}\] \[\color\red{= C_d *A_o* \sqrt{2* g* Δh}* ρ _{Air}* ρ _{Water}\;\;}\color\black{Kg/ Sec}\] \[\color\red{Cd= 0.62}\] \[\color\red{g= 9.81 ;}\] \[\color\red{A_o = 0.804* 10^{ -3}}\] \[\color\Green{On \;calculating\; mass \;of\; air\; per\; unit\; time\;=}\] \[\color\red{ 2.601*10^{ -3}*\sqrt{ Δh}}\] \[\color\red{Δh\; is\; the\; manometric\; difference\;}\] \[\color\green{Air\; fuel \;ratio=}\] \[\color\red{\dfrac{ 2.601*10^{ -3}*\sqrt{ Δh}}{0.667 *10^{ -3}}\;\;}\color\black{ kg/sec}\] \[\color\red{ =3.89 }\;\;\color\black{kg/sec}\]

Conclusion: –

To be written by student.

Next