TE LAB-PERFORMANCE TEST and HEAT BALANCE TEST on 4 STROKE MULTI CYLINDER PETROL ENGINE WITH EDDY CURRENT DYNAMOMETER LOADING

 

Ex.No:                                                                                                                        Date:

 

PERFORMANCE TEST and HEAT BALANCE TEST on 4

 STROKE MULTI CYLINDER PETROL ENGINE WITH

 EDDY CURRENT DYNAMO-METER LOADING

 

         Aim: To conduct performance test on 4stroke multi cylinder petrol engine and to measure the -BHP at constant speed keeping variable load, -Fuel consumption at variable speed, -Air consumption, -Heat balance sheet.

 

Specification of engine:

 

Four stroke 4 –cylinder ZEN petrol engine, 1294 CC capacity, water cooled variable speed.

Rated speed              : 2000 to 2500 rpm

Starting by                 : battery start by ignition method

Loading                     : by eddy current dynamometer 10HP at 3000 rpm,

Spring balance          : 0 to 50 Kg

 

Measurements:

 

1.      Air intake by engine- The engine is connected to volumetric tank of air tight; one end of the tank is fitted with an orifice 25 mm diameter, the tank is connected to U-tube manometer through ¼ inch, hose nipple fitting by polythene transparent tube. The deflection of manometer caused due to velocity difference between the tank and atmospheric air velocity measures the velocity of air by which we can calculate quantity of air flowing into the engine cylinder.

 

2.      Fuel flow measurement- The control panel is fitted with a fuel tank which is connected to a 3-way manifold where one end of the manifold is connected to measuring burette of 100 CC capacities and the other end is connected to the engine. The fuel flow to the engine can be measured by closing the stop cock provided at the top of 3-way manifold.

 

3.      Speed: Speed of the engine can be measured with a digital rpm indicator which is connected by sensor. The sensor is fitted near the rotating shaft of the prime mover, where according to the speed the pulse signals are sent to the indicator.

 

4.      Temperature’s multi-channel digital temperature indicator is connected with sensors at various points to measure temperatures of exhaust gas, cooling water circulation and room temperature.

 

5.      Rota meter and water meter: For measurement of water flow to the engine and for calorimeter Rota meter and water meter are provided respectively.

 

Procedure:

 

§  Fill the fuel tank with clean petrol.

 

§  Check the sufficient lubrication oil in the oil sump (crank case).

 

§  Check the sufficient cooling water circulation (say about 150 to 200 LPH) in the rotameter being circulated through engine.

 

§  Connect the control panel to electrical mains 230 V.

§  Keep the engine throttle (speed adjuster) to the partially open position.

 

§  Start the engine with the ignition key provided on the main panel board provided, adjust the speed, say at around 1500 to 2000 rpm

 

§  Load the engine with the help of eddy current dynamometer by operating the excitation device provided on the side of the control panel. Operate the knob till the spring balance reads at 1,2,3..kg.

 

§  Take down the manometer reading for air consumption, rpm reading and burette reading for fuel consumption in each load.

 

§  Adjust the speed say about 2000 rpm, note down the readings as above.

 

§  Repeat the procedure for different speeds to conduct the load test. Each time note down the manometer reading fuel consumption reading and rpm.

 

§  Note down the temperature readings for final reading to calculate heat balance sheet at full load.

 

Observation:

Diameter of orifice = 25mm = 0.025m

Water flow reading for calorimeter m_w = 200 - 250 CC

Calorific value of petrol fuel, CV = 44,600 kJ/kg

T₁= inlet water temperature

T₂= outlet water temperature = inlet water temperature to calorimeter

T₃= outlet water temperature from calorimeter

T₄= exhaust temperature before cooling

T₅= exhaust temperature after cooling

 

Observation 

                  Speed =                rpm,               Rotameter reading for water flow =           lpm

S. No.	Load (spring balance reading)	Time taken of 10CC of fuel consumption, tf	Manometer reading, hm=h1+h2	Cooling water temperature,0C
				T1	T2	T3	T4	T5
	kgf	sec	mm

 

Formulae:

Heat Balance Sheet:

	Description		KW		%
A.		Heat input to the engine	HI			100
a.		Heat equivalent of brake power	BP		BP/HI x 100		100
b.		Heat equivalent of friction power	FP		FP/HI x 100
c.		Heat carried away by exhaust gas, Qg =mg x Cpgas (T5-T6) Where, mg = (mair + mf) kg/min. and CPair= 1.005kJ/kgK	Qg		Qg /HI x 100
d.		Heat carried away by cooling water, Qw =mw x Cpw (T2-T1) and CPw= 4.18kJ/kgK	Qw		Qw /HI x 100
e.		Unaccounted heat loss, Quacc = A - (a+b+c+d)	Quacc		Quacc /HI x 100

Graph:

BP Vs SFC, h_mech, h_b.th

 

Pre Lab Questions:

1.      What are the 4strokes of SI engines?

2.      What is the working cycle of SI Engine?

3.      List out the performance parameters?

4.      Indicate the different types of loads?

5.      Differentiate SFC and TFC?

Post Lab Questions:

1.      Differentiate brake power and indicated power?

2.      Define brake thermal efficiency?

3.      Indicate mechanical efficiency in terms of BP and IP?

4.      What type of dynamometer used for measuring the motor output?  

5.      What type of cooling system incorporate in engine?

 

Conclusion:

 

PO Attainment:

Composed By:      

 R.Satheesh, M.E., Asso.Prof.,