1. Electrical Power Generation – 2140908
Active Learning Assignment
“Topics”
Diesel Power Station
Guided By: Prof. Rahil sir
Branch : Electrical Engineering
Div: B
Batch : B1
Presented by:
Het amin-130120109002
Abdul chhipa-130120109005
Shah harshil-130120109012
5. Fuel Supply System
In fuel supply system there are one storage tank, where oil in stored.
Strainer : This oil then pump to dry tank, by means of transfer pump.
During transferring from main tank to smaller dry tank, the oil passes through strainer
to remove solid impurities. From dry tank to main tank, there is another pipe
connection. This is over flow pipe. This pipe connection is used to return the oil from
dry tank to main tank in the event of over flowing.
From dry tank the oil is injected in the diesel engine by means of fuel injection pump.
6. Air Intake System
This system supplies necessary air to the engine for fuel combustion. It consists of
a pipe for supplying of fresh air to the engine. Filters are provided to remove dust
particles from air.
7. Exhaust System
The exhaust gas is removed from engine, to the atmosphere by means of an
exhaust system. A silencer is normally used in this system to reduce noise level of
the engine.
8. Cooling System
The heat produced due to internal combustion, drives the engine. But some parts of this
heat raise the temperature of different parts of the engine. High temperature may cause
permanent damage to the machine. Hence, it is essential to maintain the overall
temperature of the engine to a tolerable level. Cooling system of diesel power station
does exactly so. The cooling system requires a water source, water source, water pump
and cooling towers. The pump circulates water through cylinder and head jacket. The
water takes away heat from the engine and it becomes hot. The hot water is cooled by
cooling towers and is re-circulated for cooling.
9. Lubricating System
This system minimizes the water of rubbing surface of the engine. Here
lubricating oil is stored in main lubricating oil tank. This lubricating oil is drawn
from the tank by means of oil pump. Then the oil is passed through the oil filter
for removing impurities. From the filtering point, this clean lubricating oil is
delivered to the different points of the machine where lubrication is required the
oil cooler is provided in the system to keep the temperature of the lubricating oil
as low as possible.
10. Starting System
For starting a diesel engine, initial rotation of the engine shaft is required. Until
the firing start and the unit runs with its own power. For small DG set, the initial
rotation of the shaft is provided by handles but for large diesel power station.
Compressed air is made for starting.
11. APPLICATION OF DIESEL POWER
STATION
They are used as central station for small or medium power supplies.
They can be used as stand-by plants to hydro-electric power plants and steam power
plants for emergency services.
They can be used as peak load plants in combinations with thermal or hydro-plants.
They are quite suitable for mobile power generation and are widely used in
transportation systems such as automobiles, railways, air planes and ships.
Now-a-days power cut has become a regular feature for industries. The only solution
to tide over this difficulty is to install diesel generating sets.
12. DISADVANTAGES
High running charges due
to costly price of Diesel
Generates small amount of
power
Cost of lubrication very
high
Maintenance charges are
generally high
ADVANTAGES AND DISADVANTAGES OF
DIESEL POWER PLANT
ADVANTAGE
Simple design & layout of plant
Occupies less space & is compact
Can be started quickly and picks
up load in a short time
Requires less water for cooling
Thermal efficiency better that of
Steam Power Plant of same size
Overall cost is cheaper than that of
Steam Power Plant of same size
15. CYLINDER
It is the heart of the engine in which the fuel is burnt and the power is developed.
Cylinder has to withstand very high pressure and temperature because the combustion of fuel
is carried out within the cylinder so it must be cooled.
The inside diameter is called bore.
Cylinder head
Cylinder head covers top end of cylinder.
Valve mechanism, spark plug, fuel injector etc are placed on cylinder head.
16. Piston
The piston is a close fitting hollow cylindrical plunger reciprocating inside
the cylinder.
The power developed by the combustion of fuel is transmitted by piston to
the crank shaft through connecting rod.
Piston rings and pin
The piston rings are the metallic rings inserted into the circumferential
grooves provided at the top end of the piston.
Piston ring is also known as gudgeon pin
It is pin joining small and of the connecting rod and piston and it is made of
steel.
17. Connecting rod
It is the member connecting piston through piston pin and crank shaft
through crank pin.
It converts the reciprocating motion of the piston in to rotary motion of
crank shaft
Crank and crankshaft
The crank is a lever that is connected to the big end of the connecting rod
by a pin joint with its other end connected to shaft which called crankshaft.
18. Valves and fly wheels
Engine has both intake and exhaust type of valves which are operated by valve
operating mechanism
Fly wheel is a heavy wheel mounted on the crankshaft of the engine and it
minimize cyclic variation during the stroke
Crankcase and fuel pump and injector
Crank case is the lower part of the engine serving as an enclosure of the
crankshaft
Fuel pump is used in diesel engine for increasing pressure and injector is used to
inject diesel fuel in the form of spray under pressure.
19. Working of Two stroke
Diesel Engine
The construction of diesel engine is similar to two stroke petrol engine except the
fuel pump and fuel injector are there instead of carburetor and sparkplug.
It consist two stroke in the cycle.
20. First stroke
At the beginning of the first stroke, the piston is at TDC and then moves to BDC.
At TDC piston is at the end of compression, so the compressed air will attain a
temperature higher than self ignition temperature of the diesel
The injector injects a metered quantity of the diesel into the cylinder as a fine
spray. As diesel is injected it auto ignites.
The combustion of the diesel will release the hot gases which increases the
pressure and temperate in the cylinder
21. Second stroke
In this stroke the piston moves from TDC to BDC. When it covers the
transfer port, the supply of air is stop and when it moves further up it
covers the exhaust port completely stops the scavenging
Further upward motion of the piston will compress the air in the cylinder
After the piston reaches TDC the first stroke repeats again
22. Suction stroke
During this stroke, inlet valve opens and exhaust
valve is closed, the pressure in the cylinder will
be atmospheric. As the piston moves from TDC
to BDC, the volume in the cylinder increases,
while simultaneously the pressure decreases.
This creates a pressure difference between the
atmosphere and inside of the cylinder.
Due to this pressure difference only the
atmospheric air will enter into the cylinder
through air filter and inlet.
At the end of this stroke, the cylinder will be
filled completely with air and inlet valve will be
closed
Working of Four stroke Diesel Engine
23. Compression stroke
During this stroke, both inlet valve and
exhaust valve remain closed. The piston
moves from BDC to TDC. As this stroke
is being performed, the air in the cylinder
will be compressed, so pressure and
temperature of air increases.
The compression ratio of this engine is
higher than petrol engine. Due to higher
compression ratio, air will have attained a
higher temperature than self ignition
temperature of diesel fuel.
A metered quantity of the diesel fuel is
injected into the cylinder. As the diesel
fuel particles come in contact with high
temperature it will ignite automatically.
This is called self ignition
24. Power stroke
During this stroke, both the inlet
valve and the exhaust valve are
closed. The piston moves from TDC
to BDC.
The fuel injection starts nearly at the
end of compression stroke, but the
rate of fuel injection is such that
combustion maintains constant
pressure.
This piston is forced further during
the remaining part of this stroke only
due to the expansion of the burnt
gases. The engine produce
mechanical work in this stroke
25. Exhaust stroke
During this stroke , the exhaust
valve opens and inlet valve is
closed. The piston moves TDC to
BDC.
During this motion, piston pushes
the exhaust gases out of cylinder at
constant pressure.
