Perkins 1103D XK Systems Operation Testing And Adjusting page 11

KENR6912
Air is drawn in through the air cleaner into the air inlet
(6) of the inlet manifold (4). Air flow from the inlet
manifold to the engine cylinders (8) is controlled by
the inlet valves (7). There is one inlet valve and one
exhaust valve (9) for each cylinder. The inlet valve
opens when the piston moves down on the intake
stroke. When the inlet valve opens, air from the inlet
port is forced into the cylinder. The complete cycle
consists of four strokes:
•
Inlet
•
Compression
•
Power
•
Exhaust
On the compression stroke, the piston moves back
up the cylinder and the inlet valve (7) closes. The
air is compressed and this compression generates
more heat.
Note: If the cold starting system is operating, the
glow plugs (3) will also heat the air in the cylinder.
Just before the piston reaches the TC position, fuel is
injected into the cylinder via the fuel injection nozzle
(2). The air/fuel mixture ignites. The ignition of the
gases initiates the power stroke. Both the inlet and
the exhaust valves are closed and the expanding
gases force the piston downward toward the bottom
center (BC) position .
From the BC position, the piston moves upward. This
initiates the exhaust stroke. The exhaust valve (9)
opens. The exhaust gases are forced through the
open exhaust valve into the exhaust manifold (1).
Exhaust gases from exhaust manifold (1), pass
through exhaust outlet (5), and an exhaust pipe and
a silencer.
Turbocharger
Note: The turbocharger is not serviceable.
A turbocharger increases the temperature and the
density of the air that is sent to the engine cylinder.
This condition causes a lower temperature of ignition
to develop earlier in the compression stroke. The
compression stroke is also timed in a more accurate
way with the fuel injection. Surplus air lowers the
temperature of combustion. This surplus air also
provides internal cooling.
A turbocharger improves the following aspects of
engine performance:
•
Power output is increased.
•
Fuel efficiency is improved.
This document has been printed from SPI². Not for Resale
Systems Operation Section
•
Engine torque is increased.
•
Durability of the engine is improved.
•
Emissions from the engine are reduced.
Illustration 6
Typical example
Components of a turbocharger (typical example)
(1) Air inlet
(2) Compressor housing
(3) Turbocharger compressor wheel
(4) Bearing
(5) Oil inlet port
(6) Bearing
(7) Turbine housing
(8) Turbocharger turbine wheel
(9) Exhaust outlet
(10) Oil outlet port
(11) Exhaust inlet
A turbocharger is installed between the exhaust and
inlet manifolds. The turbocharger is driven by exhaust
gases which flow through the exhaust inlet (11). The
energy of the exhaust gas turns the turbine wheel
(8). Then, the exhaust gas flows out of the turbine
housing (7) through the exhaust outlet (9).
The turbocharger turbine wheel and the turbocharger
compressor wheel (3) are installed on the same shaft.
Therefore, the turbocharger turbine wheel and the
turbocharger compressor wheel rotate at the same
rpm. The turbocharger compressor wheel is enclosed
by the compressor housing (2). The turbocharger
compressor wheel compresses the air that is drawn
in from the air intake (1). The air flows into the engine
cylinders through the inlet valves of the cylinders.
The oil from the main gallery of the cylinder block
flows through the oil inlet port (5) in order to
lubricate the turbocharger bearings (4) and (6). The
pressurized oil passes through the bearing housing
of the turbocharger. The oil is returned through the oil
outlet port (10) to the oil pan.
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