Fuel Input; Pressurize - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

DI07-18
Principle of operation
• During the filling phase, the rollers are kept in contact with the cam by means of coil springs mounted on either side
of each shoe. The transfer pressure is sufficient to open the inlet valve and to move the pumping plungers apart.
Thus, the dead volume between the two plungers fills with fuel.
• When the diametrically opposite rollers simultaneously encounter the leading edge of the cam, the plungers are
pushed towards each other.
• As soon as the pressure becomes higher than the transfer pressure, the inlet valve closes. When the pressure
becomes higher than the pressure inside the rail, the delivery valve opens. Consequently, the fuel is pumped under
pressure into the rail.
• During the input phase, transfer pressure pushes back the inlet valve. Fuel enters the body of the pumping element.
The valve closes as soon as the pressure in the pumping element becomes higher than the transfer pressure.
• During the input phase, the ball of the delivery valve is subject to the rail pressure on its outer face and to the transfer
pressure on its inner face. Thus the ball rests on its seat, ensuring the pressure tightness of the body of the pumping
element. When the pressure in the element becomes higher than the pressure in the rail, the ball is unbalanced and
it opens. Fuel is then pumped into the rail at high pressure.
Roller
Plunger
<Fuel input>
This high pressure pump generates the driving torque with low peak torque to maintain the stress to driving components.
This torque is smaller than that of conventional injection pump, thus, only a small load will be applied to pump. The
required power to drive pump is determined by set pressure for rail and pump speed (delivery flow). Note that the fuel
leakage or defective pressure control valve may affect the engine output.
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
<Pressurize>
Y220_07022
FUEL SYSTEM
DI ENG SM - 2004.4