Injector At Rest; Solenoid Valve Control - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

DI07-50
Principle of Operation
Ff = pressure * space
Ff =
S
(Ff = P
(Ff = Prail S)
Fo = pressure * space
Fo =
(Fo = P
(Fo = Prail
A
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"
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
* S)
rail
* S)
rail
A)
Valve opens
Needle closed
No injection Start of injection
Y220_07104
Valve open Valve closes
Needle opens Needle open
End of injection

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.
Valve closed
Needle closed
No injection
Y220_07103
FUEL SYSTEM
DI ENG SM - 2004.4