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ENGINE 1.3 QUADRAJET (75PS)
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3A.1.5.2 COMPONENTS
3A.1.5.2.1 VACUUM PUMP
The CP1 pressure pump (1) is the radialjet type with
three radial pistons (tot al capacity 0.567 cc) and is
controlled by the camshaft by means of an oldham
joint (2); there are no timing positions.
STRUCTURE
Each pumping unit consists of:
Q
a piston operated by a cam in one piece with the
pump shaft;
Q
a plate-type intake valve;
Q
a ball delivery valve.
Because the pressure pump must be fed at a
pressure of at least 0.7 bar , the fuel system is
equipped with an auxiliary fuel pump submerged in
the tank.
The maximum delivery pressure reaches 1400 bar.
The pressure pump is lubricated and cooled by the
fuel via special channels.
3A.1.5.2.2 INJECTORS
The injectors are fitted on the cylinder head and
controlled by the injection control unit.
The injector may be divided into two sections:
Q
actuator/atomizer consisting of pressure rod (1),
pin (2) and nozzle (3);
Q
control solenoid consisting of coil (4) and pilot
valve (5).
Injector operation is divided into three stages.
REST POSTION, the coil (4) is deactivated and the
shutter (6) is in the closed position to prevent fuel from
being introduced into the cylinder Fc > Fa (Fc: due to
line pressure acting on the control area (7) of the rod
(1); Fa: due to line pressure acting on the feed volume
(8).
START OF INJECTION, the coil (4) is energized and
causes the shutter (6) to rise.
Control volume fuel (9) flows out towards return
manifold (10) to bring about a pressure drop on control
area (7). Simultaneously, the line pressure flowing
through the intake duct (12) exercises a force Fa >
Fc in the supply volume (8) to cause the pin (2) to lift
and allow fuel into the cylinders.
END OF INJECTION, the coil (4) is deactivated and
causes the shutter (6) to return to closed position.
This rebalances the forces so that the pin (2) returns
to the closed position and the injection ends.
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