1.3 MULTIJET 16V
(75 & 90 HP)
FIAT PUNTO TRAINING OUTLINE
Fiat Auto S.p.A.
After Sales Training
The electric injector operation can be divided into three phases.
REST POSITION: coil (4) is de-energized, and shutter (6) is in the closing position and does
not allow fuel to be let into cylinder Fc > Fa (Fc: due to the line pressure that acts on control
area 7 of rod 1; Fa: due to the line pressure that acts on feed volume 8).
START OF INJECTION: coil (4) is energized and causes shutter (6) to be raised.
The control volume fuel (9) flows out toward return manifold (10), thus causing a pressure
drop on control area (7). At the same time, the line pressure through feed duct (12) exerts a
force Fa > Fc in feed volume (8), thus causing pin (2) to be lifted, with resulting fuel flow into
the cylinders through holes (3) (such holes amount to 6 in the CR1 MI 2.2 injector; they feature
a diameter of 0.121 mm and a flow rate of 280 cm3 / 30 s at 100 bar).
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