4-12 FI SYSTEM AND INTAKE AIR SYSTEM
Needle valve
Plunger
Solenoid coil
Filter
FUEL PRESSURE REGULATOR
The fuel pressure regulator consists of the spring and valve. It keeps absolute fuel pressure of 300 kPa (3.0
kgf/cm
2
, 43 psi) applied to the injector at all times.
When the fuel pressure rises more than 300 kPa (3.0 kgf/cm
2
, 43 psi), the fuel pushes the valve in the
regulator open and excess fuel returns to the fuel tank.
FUEL INJECTOR
The fuel injector consists of the solenoid coil, plunger, needle valve and filter.
It is an electromagnetic type injection nozzle which injects fuel in the throttle body according to the signal
from the ECM.
When the solenoid coil of the injector is energized by the ECM, it becomes an electromagnet and attracts the
plunger. At the same time, the needle valve incorporated with the plunger opens and the injector which is
under the fuel pressure injects fuel in conic dispersion. As the lift stroke of the needle valve of the injector is
set constant, the volume of the fuel injected at one time is determined by the length of time during which the
solenoid coil is energized (injection time).
Fuel from
fuel pump
Spring
Valve
Fuel from
fuel pump
Spring
Valve
Fuel returns to the
fuel tank
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