Page 136 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

which equal quantity of diesel passes through the pump to the injectors. This pump is driven by the camshaft.
From this pump, the diesel gets filtered and goes to the metering valve and from here the diesel goes to the
injector through the injector pipes. In this pump the pressure increases from 400 to 700 bar.

Types of governors

Governor: Governor is used to regulate the maximum and minimum speed of any engine. In diesel engines
a governor is used for this purpose in conjunction with the fuel injection pump. These governors control the
minimum and maximum speed of the engine by controlling the amount of diesel supply.
There are mainly four types of governors
1 Mechanical or Centrifugal Governor
Centrifugal ball weight or fly weight is used in this type of governor. These weights are mounted on the camshaft
of the fuel injection pump.
When the engine runs at slow speed, their expansion is less and when the engine runs at high speed, the weights
also rotate faster and expand outwards more. Therefore, the control rods related to them also move more or less
outwards according to the spread of weight.
Type
The control rod in the fuel injection pump controls the maximum and minimum speed of the engine by moving
back and forth and rotating the plunger through the control sleeve, increasing or decreasing the amount of diesel
in the diesel supply.

In other words, it can be said that the governor controls the quantity of diesel in the diesel supply as per the
requirement of the engine.
• Pneumatic Governor
In this type of governor, a diaphragm is used, which is the basis of the system. This is affected by the depression
created in the inlet manifold during the suction stroke. This governor consists of two main (ii) hydraulic units – inlet
manifold unit and diaphragm unit.
There is a butterfly fitted in the inlet manifold, which is connected to the accelerator. There is also a venture
arrangement in the inlet manifold, which is directly connected to the diaphragm unit through a pipe. When the
engine runs, there is a suction effect in the inlet manifold during the suction stroke. This creates a vacuum in the
venture, which has its effect on the diaphragm. This diaphragm, which is attached to a spring, is also connected
to the control rod.

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CITS : Automotive - Mechanic Diesel - Lesson 31 - 38 CITS : Automotive - Mechanic Diesel - Lesson 31 - 38