3-17 ENGINE CONTROL SYSTEM
FUEL PRESSURE REGULATOR
The fuel pressure regulator is located in vapor separator.
The regulator’ function in the system is to maintain a constant fuel pressure relative to the injector while the
engine is operating.
The regulator diaphragm chamber is open to the vapor separator chamber to keep the pressure balanced.
Fuel pressure, adjusted by the regulator, is constantly maintained higher than the pressure in vapor sepa-
rator chamber by approx. 250 kPa (2.55 kg/cm
2
, 36.3 psi.).
By-pass fuel is returned back to the fuel vapor separator chamber.
FUEL INJECTOR
The fuel injector is an electromagnetic valve operated by a
signal from the ECM.
When the injection signal is supplied to the fuel injector, the
solenoid coil is energized pulling up the plunger.
This opens the injector needle valve and injects fuel.
Because the fuel pressure is kept constant, the amount of fuel
injected is determined by the amount of time (duration) the
valve is open.
Solenoid coil
Filter
Fuel inlet
Needle valve
Plunger
Fuel inlet
Filter
VALVE CLOSED
(below 2.55 kg/cm
2
)
VALVE OPENED
(over 2.55 kg/cm
2
)
from Delivery line
from Delivery line
To Vapor separator
chamber
(Fuel return)
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