1.3 MULTIJET 16V
(75 & 90 HP)
FIAT PUNTO TRAINING OUTLINE
Fiat Auto S.p.A.
After Sales Training
3.6 Fuel feed system
3.6.1 Features
This fuel injection system makes use of electronically controlled high injection pressure and
fuel supply obtained by means of one main injection and one or several pilot injections
(according to the engine’s operating conditions), which are electronically controlled by the
injection control unit through electric injector (CR1MI2.2). This system is capable of carrying
out up to five cycle injections (depending on the engine’s operating conditions).
The pressure value represents one of the main parameters in order to optimize fuel
consumption and exhaust smoke levels.
The engine control by means of several pilot injections makes preheating possible in the
combustion chamber, so as to avoid the pressure peak caused by quick combustion, thus
ensuring smoother operation, and also allows emissions to be further reduced.
The injection pressure can be controlled thanks to the construction features of the system,
which is equipped with a pressure pump, pressure regulator, pressure sensor and separate
electric injectors, all of which are managed by a control unit. Thus, the injection pressure is
independent from the engine rotation speed.
Below are the main features of the fuel feed system:
high injection pressure: 1,400 bar (75 HP) 1,600 bar (90 HP);
the injection pressure can be modulated from 150 to 1,400/1,600 bar under any working
condition of the engine;
fuel is let in up to 50 mm3/cycle within engine speeds of 100 to 5,200 r.p.m.;
accurate injection control, both as advance and duration;
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one or two pilot injections before the T.D.C., manages according to the revs number and the
engine load, which make it possible to distribute the pressure into the combustion chamber
more evenly, with lower noise levels.
