Supply Pump - wsm M108S Workshop Manual

M108S, WSM

[2] SUPPLY PUMP

The supply pump is primarily composed of the pump
unit (eccentric cam, ring cam, two plungers), the SCV
(suction control valve) (2), the fuel temperature sensor
and the feed pump (trochoid type), and is actuated at 1/
2 the engine crankshaft rotation.
The two compact pump unit plungers are positioned
symmetrically above and below on the outside of the ring
cam.
The fuel discharge quantity is controlled by the SCV,
in order to reduce the actuating load and suppress the
rise in fuel temperature. This system adopts the normally
open type (the suction valve opens when not energized)
SCV.
(1) Fuel Temperature Sensor
The fuel is suctioned by the feed pump (6) from the
fuel tank and sent to the SCV (4). At this time, the
regulating valve (5) adjusts the fuel pressure to below a
certain level. The fuel sent from the feed pump (6) has
the required discharge quantity adjusted by the SCV (4),
and enters the pump unit through the suction valve (3).
The fuel pumped by the pump unit is pumped through the
delivery valve (1) to the rail.
Feed Pump
The trochoid type feed pump (6), which is integrated
in the supply pump, draws fuel from the fuel tank and
feeds it to the two plungers (2) via the fuel filter and the
SCV (Suction Control Valve) (4). The drive shaft (8)
actuates the outer/inner rotors of the feed pump (6), thus
causing the rotors to start rotating. In accordance with
the space that increases and decreases with the
movement of the outer and inner rotors, the feed pump
(6) draws fuel into the suction port and pumps fuel out the
discharge port.
Regulating Valve
The regulating valve (5) keeps the fuel feed pressure
(discharge pressure) below a certain level. If the pump
speed increases and the feed pressure exceeds the
preset pressure of the regulating valve (5), the valve
opens by overcoming the spring force in order to return
the fuel to the suction side.
(1) Delivery Valve
(2) Plunger
(3) Suction Valve
(4) SCV
(5) Regulating Valve
(6) Feed Pump
(7) Ring Cam
(8) Drive Shaft
1-M13
ENGINE
(2) SCV (Suction Control Valve)
W1015273
A : To the Rail
(a) Fuel Tank
(b) Fuel Filter
W1015396
KiSC issued 05, 2012 A