Page 135 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

Fuel injection pump and its type
Fuel injection pump is an important component in a diesel engine, which works to transmit the appropriate
amount of fuel in the diesel engine at high pressure (120 to 200 bar) through an injector connected to the cylinder
with pressure in the cylinder. Fuel injection pumps are generally of two types.
i Distributed type fuel injection pump
ii In-line fuel injection pump
i Distributed type fuel injection pump: This type of pump has a pumping element and in this the fuel is
distributed to each cylinder with the help of a rotor. The rotor has a central longitudinal passage and two pairs
of radial holes located at different heights. Out of these, one pair is connected to the inlet of the pump through
the central passage and the other pair is connected to the delivery lines of the injectors of different cylinders.
Such pumps are usually small in size and light in weight.

ii In-line fuel injection pump: This type of pump is fitted in the fuel line. It is a high pressure pump, which
supplies diesel at high pressure to all the injectors sequentially and firing at the appropriate time. When the
plunger is in its bottom position, fuel from the feed pump enters through the barrel inlet port. In this, the nozzle
rotates one by one and delivers diesel to the pipe of each injector. This pump has a pumping element, through

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CITS : Automotive - Mechanic Diesel - Lesson 31 - 38