This document provides an introduction and examples for testing internal combustion engines. It begins with definitions of testing and its purpose, which is to determine information that cannot be obtained through calculations, confirm design data, and satisfy customers regarding engine performance. Several examples of brake power and torque calculations for engines are shown. The learning outcomes of the document are not specified.

1. WELCOME YOU ALL

2. TOPIC: TESTING OF IC ENGINES
Compiled By
Md. Isarot Hossan
ID: 142014001
Department of Textile
Engineering
Green University of
Bangladesh19/12/2016 2

3. CONTENTS
 What is Testing?
 Purpose of Testing.
 Some examples.
 Learning Outcomes.
19/12/2016 3

4. TESTING
In general, testing is finding out how
well something works…….
Determined and documented by
subjecting the item to a set of
operating conditions.
19/12/2016 4

5. PURPOSE OF TESTING
To 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.
19/12/2016 5

6. 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.
19/12/2016 6

7. SOLUTION:
Given,
Speed of the engine, N=1000 rpm
Load on the brake, W=1000 N
Length of the brake, L=750 mm=
𝟕𝟓𝟎
𝟏𝟎𝟎𝟎
= 0.75 m
1. Brake torque= W*L=1000*0.75=750 J
2. Brake power of the engine =
𝐓∗𝟐𝛑𝐍
𝟔𝟎
=
𝟕𝟓𝟎∗𝟐𝛑∗𝟏𝟎𝟎𝟎
𝟔𝟎19/12/2016 7

8. 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.
19/12/2016 8

9. 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
19/12/2016 9

10. SOLUTION:
Brake power =
𝐖−𝑺 ∗π∗ 𝐃−𝐝 ∗𝐍
𝟔𝟎
=
𝟐𝟏𝟎−𝟑𝟎 ∗π∗ 𝟎.𝟔−𝟎.𝟎𝟎𝟓 ∗𝟒𝟓𝟎
𝟔𝟎
=2523.49 Watt
19/12/2016 10

11. 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.
19/12/2016 11

12. 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 =
𝛑𝐃²
𝟒
=
𝛑(𝟎.𝟏𝟓)²
𝟒
= 0.017719/12/2016 12

13. SOLUTION:
Indicated power, I.P =
𝟏𝟎𝟎∗Pm∗𝐋∗𝐧∗𝐀∗𝐊
𝟔𝟎
=
𝟏𝟎𝟎∗5.5∗𝟎.𝟒∗𝟎.𝟎𝟏𝟕𝟕∗𝟏
𝟔𝟎
= 7.78 kW
Therefore, The Mechanical efficiency , Ƞm =
𝐁.𝐏
𝐈.𝐏
*100
=
𝟓
𝟕.𝟕𝟖
*10019/12/2016 13

14. 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.
19/12/2016 14

15. 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
19/12/2016 15

16. SOLUTION:
We know, Ƞm =
B.P
I.P
0.85=
23.5
I.P
I.P= 23.5 ∗ 0.85 = 27.7 kW
Again, I.P=
𝟏𝟎𝟎∗Pm∗𝐋∗𝐧∗𝐀∗𝐊
𝟔𝟎
23.5 =
𝟏𝟎𝟎∗𝟖.𝟓∗𝟏.𝟓𝐃∗𝟐𝟓𝟎𝟎∗
𝛑𝐃²
𝟒
∗𝟒
𝟔𝟎
D³ = 0.000165 = 55 mm
L = 1.5D = 1.5*55 =82.5 mm
19/12/2016 16

17. ANY QUESTION???