Principle Of Operation; Characteristics Of The Transfer Pump - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

Principle of operation

Consider the chamber between the rotor, the liner and two successive blades (refer to above figure).
• When the chamber is in position 1, the volume of the chamber is minimal. The changes in volume according to the
angle of rotation of the rotor are small.
• The rotor makes a quarter turn clockwise. The previous chamber is now in position 2.
The inlet orifice is uncovered. The volume contained in the chamber quickly rises. The pressure inside the chamber
drops sharply. Fuel is drawn into the chamber.
• The rotor continues to rotate. It is now in position 3. The inlet and outlet orifices are now sealed off. The volume area
controlled by the rotor, the liner and the two blades is at the maximum. The changes in volume according to the
angle of rotation of the rotor are small.
• The rotor continues to rotate. It is finally in position 4. The outlet orifice is uncovered. The volume area controlled by
the rotor, the liner and the blades decreases quickly. The pressure inside the chamber rises sharply. The fuel is
expelled under pressure. The depression caused by the transfer pump's rotation is sufficient to draw in diesel fuel
through the filter. The transfer pump is driven by the shaft of the HP pump, transfer pressure thus rises with engine
speed. A regulating valve allows the transfer pressure to be maintained at a practically constant level (about 6 bar)
throughout the whole range of engine operations by returning some of the fuel to the pump inlet.
Fuel
pressure
(bar)

Characteristics of the transfer pump

Regulating pressure
Volume controlled
Flow
Intake capacity
FUEL SYSTEM
DI ENG SM - 2004.4
Housing
Chamber
Fuel pump speed (rpm)
6 bar
3
5.6 cm /revolution
90 /h at 300 rpm pump
650 /h at 2,500 rpm pump
65 mbar at 100 rpm pump
Rotor
Blade
Y220_07025
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
DI07-13
Y220_07026