2. •The basic task in the engine design and development
of engine to reduce the cost of production and improve
the efficiency and power output.
•In general wide variety of engine tests, the nature and
type of test to be conducted depend upon a large
number of factors.
•In this chapter the certain testing and measurements
and tests are considered.
3. 1. Frictional power
2. Indicated power
3. Break power
4. Fuel consumption
5. Air flow
6. Speed
7. Exhaust and coolant temperature
8. Emission
9. Noise
10. Combustion phenomenon
4. • The difference between the IP & BP.
• The internal losses in engine are essentially of
kinds, viz., pumping losses and friction losses.
• The friction is made up of the friction between the
piston and cylinder walls, piston rings and cylinder
walls, and between the crankshaft and camshaft
and their bearings.
5. willian’s line method
Morse test
Motoring test
From the measurement of indicated and
break power
Retardation test
6.
7. • This method is applicable only for multi
cylinder engine.
• The following graph shows the unshaded area
of the indicator diagram is a measure of the
gross power, gp developed by the engine, the
dotted area being the pumping power, pp.
Net indicated power per cycle = gp-pp
8.
9. if there are k cylinders ,then
Where ip, bp and fp are respectively indicated,
break and frictional power and the suffix k
stands for the cylinder number.
If the first cylinder is cut-off. It will not produce
any power but it will have a friction, then
1..........
1
4321
k
kkk fpbpipipipipip
10. Subtracting equation 2 from 1
Similarly we can find the indicated power of the
cylinder, viz,…
The total indicated power developed by the
engine, , is given by
2..........
2
4321
k
kkk fpbpipipipipip
k
k
k
k bpbpip
21
1
kipipipip ,...,, 432
kip
3................................
1
k
kk ipip
11. When all the k cylinders are working, it is possible to
find the break power , of the engine.
The frictional power of the engine is given by
The method though determines the fp at the
conditions very near to the actual operating
temperatures at the test speed and load,
kbp
kkk bpipfp
12. Motoring method ,however, gives the reasonably
good results and is very suitable for finding the
losses imparted by various engine components.
• This test involves the method of retarding the
engine by the cutting fuel supply.
• The engine is to made to run at no load and
rated speed taking into as usual precautions.
• When the engine is running under steady
operating conditions the supply of fuel is cutoff
13. • The fuel will cut off simultaneously the time of
fall in speeds by say 20%, 40%, 60%, 80% of
the rated speed is recorded.
• The following graph which will shows time fall
in speed (x-axis) and speed (y-axis) at no load
as well as 50% load condition drawn as shows
in fig.
14. Indicated power of an engine tells about the
health of the engine and also gives an
indication regarding the conversion of
chemical energy in the fuel into heat energy.
In order to estimate the indicated power of
an engine the following methods are usually
followed.
1. Using the indicator diagram
2. By adding two measured quantities viz,..
Break power and friction power.
15. In order to investigate the individual cycle,
electronic indicators have been developed
which consists of four parts.
1. Pressure pick up
2. Preamplifying device
3. Time base recording device
4. Display unit
Ex; pressure transducer
16. It involves the torque and angular speed of the
engine out put.
The torque measuring device is called a
‘Dynamometer’.
Types of dynamometer.
1. Absorption dynamometer.
2. Transmission dynamometer.
17.
18.
19.
20. There are the two ways of expressing fuel
consumption viz,.. By volume are by weight
during a specified time. For an automobile it
is expressed in terms of kilo meter per liter.
The two basic fuel measurements are
1. Volumetric type
2. Gravimetric type
