Valve; Spacer - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

The maximum injection pressures are approximately 1,600 bar. The forces to be overcome in order to lift the needle of
the injector are therefore very large. Because of this, it is impossible to directly control the injector by using an electro-
magnetic actuator, unless very high currents are used, which would be incompatible with the reaction times required for
the multiple injections. The injector is therefore indirectly controlled by means of a valve controlling the pressurizing or
discharging of the control chamber located above the needle:
• When the needle is required to lift (at the start of injection): the valve is opened in order to discharge the control
chamber into the back leak circuit.
• When the needle has to close (at the end of injection): the valve closes again so that pressure is re-established in
the control chamber.

Valve

In order to guarantee response time and minimum energy
consumption:
• The valve must be as light as possible.
• The valve stroke must be as short as possible.
• The effort needed to move the valve must be minimal, which
means that the valve must be in hydraulic equilibrium in
the closed position.
Spring pressure ensures contact between the valve and its
seat. To lift the valve, it is therefore required to overcome the
force being applied by this spring.

Spacer

The spacer is situated underneath the valve support. It inte-
grates the control chamber and the three calibrated orifice
which allow operation of the injector. These orifices are:
• The injector supply orifice (Nozzle Path Orifice: NPO)
• The control chamber discharge orifice (Spill Orifice: SPO)
• The control chamber filling orifice (Inlet Orifice: INO)
FUEL SYSTEM
DI ENG SM - 2004.4
Valve
Volume
under
high
pressure
Valve
Spill
orifice
Spacer
INO inlet
irifice
NOP nozzle
path orifice
DI07-49
Contact
making seal
Depressuriza-
tion grooves
Volume under
vacuum
Y220_07101
SPO spill
orifice
Control
chamber
Y220_07102
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN