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WHAT IS DIESEL ENGINE
Is an internal combustion engine, which
derives its power from the heat generated
when a compressed air-fuel mixture is
ignited within its cylinder
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OPERATING PRINCIPLES
It is based on fundamental law of physic
which states that gas will expand upon
application of heat. If the gas be confines,
however with no outlet for expansion, then
the pressure of the gas will be increased
when the heat is applied as the result of
igniting the compressed gas in an internal
combustion engine
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As piston moves down the
cylinder block, due to the
suction effect, it draws air into
the cylinder through the open
inlet valve. The exhaust valve
remain closed during this
stroke
INDUCTION STROKE
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The piston moving up
the cylinder with both
inlet and exhaust valves
closed, compresses the
air to about 600 degrees
C
COMPRESSION STROKE
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The high temperature of the
compressed air ignites the
fuel spray and the resulting
pressure forces the piston
downwards in its working
power stroke
POWER STROKE
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EXHAUST STROKE
Near the end of the power
stroke, the exhaust valve
opens and as the piston
returns toward the cylinder
head, the burnt gases are
pushed out. At the top of the
stroke, the exhaust valve
closes and the air inlet valve
opens
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FIRING ORDER
• Firing order ialah turutan sistematik
diantara silinder-silinder injin dalam proses
membakar bahan bakar (fuel) untuk
mendapatkan kuasa
• Untuk injin 6 silinder ia tidak mengikut
turutan 1,2,3,4,5,6
• Firing order ini berbeza-beza mengikut
jenama-jenama injin
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ENGINE CLASSIFICATION
• Horse power (3h.p to 40,000h.p)
• Number of cylinder (1 to 24 cylinders)
• Cycles of operation (2 or 4 stroke)
• Arrangement of cylinders
• Action of the piston
• Types of fuel ignited
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DIESEL ENGINE
EFFICIENCY
• Today diesel engine is up to 42 %, better
than petrol engine without fuel injection
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NATURALAIR ASPIRATED
ENGINE
The flow of air depends entirely on the
piston induction stroke and the inlet valve
opening. Due to the resistance to the flow of
air through the manifold and valve, the air
obtained by the naturally aspirated method
is often insufficient to provide complete
combustion of the fuel. To overcome the
problem turbocharged has been developed.
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TURBOCHARGED ENGINE
Is a device consisting of an engine exhaust
operated turbine, which drives a common
shaft, centrifugal compressor. The air is
compressed by the compressor and forced
into the combustion chamber with bigger
volume so that better combustion and better
power can be achieved
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ADVANTAGES OF
TURBOCHARGED ENGINE
• Increased horsepower from an engine of a
given capacity
• Increase fuel economy
• Usually cost less than a naturally aspirated
engine of the same horsepower
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SUPERCHARGED ENGINE
Where the exhaust power is not adequate or
it may affect engine efficiency or because of
technical reason other means of driving the
compressor such as electric motor is used.
This is called supercharger and applicable to
larger size diesel engines.
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INTERCOOLER/AFTERCOOLER
Cold air has greater density than warm air, it
thus contain more oxygen molecules per
unit of volume. By cooling the charging air,
more fuel can be burnt which means that a
greater output can be obtained. Furthermore
the cooling reduces the thermal stresses on
the combustion chamber. Air can be cooled
by either the radiator fan, engine coolant or
fan.
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SISTEM BAHAN API
• Storage tank Governor
• Day tank High pressure pipe
• Strainer Injectors
• Feed pump Returned pipe
• Fine fuel filter
• Water separator
• Bleeding pump
• Fuel supply valve
• Fuel injection pump
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FUEL INJECTION SYSTEM
• Fuel must be metered in the correct quantity
• Correct opening pressure
• Injected at the right time
• Injected in fine atomized form
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FUEL SOLENOID
Fuel solenoid adalah sebuah gelong yang
mengawal injap bekalan bahan api.
Pemberhentian enjin adalah dengan
memutuskan bekalan bahan api iaitu dengan
menutup injap tersebut melalui tindakan
gelong fuel solenoid melalui litar kawalan
didalam papan AMF
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KELAJUAN ENJIN
Kelajuan enjin dikawal dengan mengawal
banyaknya bahan api yang dibekalkan
kepada injector. Tugas ini dilakukan oleh
governor. Governor mengesan kejatuhan
kelajuan atau terlebih laju dan menambah
atau mengurangkan bekalan bahan api
supaya kelajuan dapat dikekalkan pada
tahap yang ditetapkan
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JENIS TANGKI
DAY TANK – small quantity, for daily
consumption
STORAGE TANK – bigger quantity, for
one or a group of generators, monthly
consumption
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KEMAMPUAN TANGKI
Secara purata setiap 10 kW menggunakan 1
gelen minyak disel untuk 1 jam. Jadi untuk
set 60 kW kita akan menggunakan 6 gelen
minyak disel untuk tiap-tiap jam ia
beroperasi. Day tank yang standard
berkapasiti 1000 liter. Jika bekalan sebulan
sekali minyak diperlukan 6gelen x 8jam
sehari x 30hari +5% tambahan = 1500gelen
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FUEL TRANSFER PUMP
• Electric fuel pump - to pump fuel from
storage tank to daily tank if required
• Gravity feed – fuel from storage or daily
tank flow freely based on gravity pressure
to daily tank or to the engine
• Normally back up by manual pump
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SISTEM PELINCIRAN
• Sump
• Oil pump
• Oil filter/Strainer (primary & secondary
filter)
• Oil cooler
• Oil pressure switch
• Jenis minyak/kelikatan minyak (30/50)
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CHARGING SYSTEM
• Static charger – normal supply, bila
janakuasa tidak beroperasi
• DC alternator charger, bila janakuasa
beroperasi (prime power)
• Constant voltage charger
• Constant current charger
• Charging current and voltage
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MEMULAKAN INJIN
• Periksa bahan api (disel)
• Periksa minyak pelincir
• Periksa air penyejuk
• Periksa air bateri
• Periksa voltan bateri
• Periksa semua belting
• Pemerhatian am, kebersihan, keselamatan
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SENGGARAAN ENJIN
• Minyak pelincir
• Penapis minyak
• Air radiator
• Penapis udara
• Elektrolid bateri
• Minyak hidraulik governor
• Habok, kotoran & sawang
