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TOPIC: TESTING OF IC ENGINES

Compiled By Md. Isarot Hossan ID: 142014001 Department of Textile Engineering Green University of Bangladesh

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CONTENTS

What is Testing? Purpose of Testing. Some examples. Learning Outcomes.

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TESTINGIn general, testing is finding out how well something works…….Determined and documented by subjecting the item to a set of operating conditions.

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PURPOSE OF TESTINGTo determine the information, which can’t be obtained by calculations.To confirm the data used in design, the validity of which may be doubtful.To satisfy the customer regarding the performance of the engine.

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SOME EXAMPLES.

Ex-01:The following data were recorded during a test on an oil engine: Speed of the engine=1000 rpm. ; Load on the brake=1000 N ; Length of the brake=750 mm. Determine: 1. Brake torque; & 2. Brake power of the engine.

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SOLUTION: Given, Speed of the engine, N=1000 rpm Load on the brake, W=1000 N Length of the brake, L=750 mm=

1. Brake torque= W*L=1000*0.75=750 J2. Brake power of the engine 78539.82 Watt

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SOME EXAMPLES.Ex-02: A rope brake has brake wheel diameter of 600 mm & the diameter of rope is 5 mm. The dead load on the brake is 210 N & spring balance reads 30 N. If the engine makes 450 rpm, find the brake power developed.

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SOLUTION: Given, Brake wheel Diameter, D = 600 mm = 0.6 m Diameter of rope, d = 5 mm = 0.005 m The dead load on the brake, W = 210 N Spring balance read, S = 30 N Engine speed, N = 450 rpm

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SOLUTION:Brake power 2523.49 Watt

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SOME EXAMPLES.Ex-03: A gas engine has piston diameter of 150 mm, Length of Stroke 400 mm & mean effective pressure 5.5 bar. The engine makes 120 explosions per minute. Determine the Mechanical efficiency of the engine, If its B.P. is 5 kW.

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SOLUTION: Given, Piston diameter, D = 150 mm = 0.15 m Length of Stroke, L = 400 mm = 0.4 m Mean effective pressure, Pm = 5.5 bar Explosions per minute, n = 120 B.P = 5 kW Let, K = 1 And, A 0.0177

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SOLUTION:Indicated power, I.P kWTherefore, The Mechanical efficiency Ƞm *100 *100 64%

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SOME EXAMPLES.Ex-04: A four cylinder two stroke cycle Petrol engine develops 23.5 kW brake power at 2500 rpm. The Mean effective pressure on each piston is 8.5 bar & the Mechanical efficiency is 85% . Calculate the diameter & Stroke of each cylinder. Assuming the length of stroke equal to 1.5 times the diameter of cylinder.

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SOLUTION: Given, No. of cylinder, K= 4 Mean effective pressure, Pm = 8.5 bar Mechanical efficiency Ƞm = 85% = 0.85 B.P = 23.5 kW n=N=2500

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SOLUTION:We know Ƞm 0.85 I.P 27.7 kWAgain, I.P D³ 0.000165 55 mmL 1.5D 1.5*55 82.5 mm

ANY QUESTION???