Page 213 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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Engine systems 197

Figure 2.237 Electronic fuel injection system components. (Source: Bosch Media)

Simultaneous petrol injection

Cyl 1
Cyl 2
Cyl 3
Cyl 4

Sequential petrol injection

Cyl 1
Cyl 2
Cyl 3
Cyl 4
0 360 720
Intake valve open

Petrol injection
Ignition

Figure 2.238 Types of fuel injection systems. (Source: Bosch Media)

point (SPI) or central point (CPI) systems. However they are named, the injector
is positioned in a housing positioned on the inlet manifold in much the same
position as the carburettor was traditionally fi tted.
The port fuel injection (PFi) or multipoint (MFi) systems have individual injectors
for each cylinder. The injectors are fi tted so that fuel is sprayed into the inlet
ports. These systems are either simultaneous, where all injectors operate at the
same time, or sequential, where each injector operates on the induction stroke
of each cylinder in turn ( Fig. 2.238 ). Multipoint systems are now by far the most
common, even on smaller vehicles.
A more recent development has been the introduction of a gasoline direct
injection (GDi) system, where the fuel is injected into the combustion chamber
( Fig. 2.239 ).