SsangYong Rexton. Manual — part 83
DI07-48
CHANGED BY
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AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.4
Y220_07100
INJECTOR
The C21 labels including injector characteristics are attached in each injector. These C21 values should be input to ECU
by using Scan-i when replacing the ECU or injectors.
Special cautions:
1. Plug the openings of hoses and pipes with the sealing caps.
2. Replace the copper washer with new one plus injector holder bolt & washer.
3. Tighten the injector holder bolts with the specified tightening torque.
4. Be careful not to drop the injector.
Specifications
Length:
· Injector body 181.35 mm
· Injector nozzle 22.155 mm
Nozzle basic:
5 Holes, 146°C Cone Angle,
840 mm
3
/min
Control: PWM type (solenoid injector)
Tightening: Clamping by fork
Fuel return: Nipple
C2I label
C2I value
Cap nut
Washer
Nozzle needle
Nozzle body
Adaptor plate
Control valve
Bobbin
Nozzle holder body
Leak off nipple
Edge filter
DI07-49
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.4
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.
Y220_07102
INO inlet
irifice
NOP nozzle
path orifice
SPO spill
orifice
Control
chamber
Spacer
Y220_07101
Valve
Volume
under
high
pressure
Valve
Spill
orifice
Contact
making seal
Depressuriza-
tion grooves
Volume under
vacuum
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)
DI07-50
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.4
Ff =
(Ff = Prail S)
Fo =
(Fo = Prail A)
S
A
Y220_07103
Principle of Operation
Injector at rest
The valve is closed. The control chamber is subject to the rail
pressure.
The pressure force applied by the fuel onto the needle is:
Ff = S * P
rail
The needle is closed and hence there is no fluid circulation
through the NPO orifice. While static, the nozzle produces no
pressure drop. The cone of the needle is therefore subject to
the rail pressure. The force applied by the fuel to the needle is:
Fo = A * P
rail
Since Ff > Fo, the needle is held in the closed position. There
is no injection.
Solenoid valve control
When the solenoid valve is energized, the valve opens. The
fuel contained in the control chamber is expelled through the
discharge orifice known as the Spill Orifice (SPO).
As soon as Ff > Fo, the needle remains held against its seat
and there is no injection.
Y220_07104
Ff = pressure
*
space
(Ff = P
rail
*
S)
Fo = pressure
*
space
(Fo = P
rail
*
S)
Valve closed
Needle closed
No injection
Valve opens
Needle closed
No injection
Valve open
Needle opens
Start of injection
Valve closes
Needle open
End of injection
Valve closed
Needle closed
No injection
* S: The area of the flat upper surface of the injector’s needle
* A: The area of the needle surface situated above the section
of contact between the needle and its seat
* Ff: The force applied by the fuel onto section “S”
* Fo:The force applied by the fuel onto section “A”
DI07-51
CHANGED BY
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AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.4
Start of injection
As soon as Ff < Fo, or in other words:
P
control
< P
rail
* A/S
The needle lifts and injection begins. As long as the valve is open, the injector’s needle remains lifted. When injection
begins, fuel circulation is established to feed the injector. The passage of the fuel through the inlet orifice of the injector
(similar to a nozzle) leads to a pressure drop which depends on the rail pressure.
When the rail pressure is at its highest (1600 bar), this pressure drop exceeds 100 bar. The pressure applied to the cone
of the needle (the injection pressure) is therefore lower than the rail pressure.
End of injection
As soon as the solenoid valve is de-energized, the valve closes and the control chamber is filled. Since the needle is
open, the thrust section areas situated on either side of the needle is therefore to apply different pressures to each of
these faces. The pressure in the control chamber cannot exceed the rail pressure, so it is therefore necessary to limit
the pressure applied to the needle’s cone. This pressure limitation is achieved by the NPO orifice which produces a
pressure drop when fuel is passing through it.
Prail * S (Prail - P) * S
When static, this pressure drop is zero. When the pressure in the control chamber becomes higher than the pressure
applied to the needle’s cone, the injection stops.
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