SERVICE MANUAL
GENERAL
Section 1
*
Code for Robert Bosch governor number
RQV 350 1200 MW 43-5:
R
= Flyweight governor
Q
= Fulcrum lever model
V
= Variable speed governing (all-speed)
350
= Low idle pump speed
1200
= Full load rated speed
MW
= Fits on "MW" size pump
43-5
= Application number
** Code for Robert Bosch combination number
PES 6MW 100/320 RS 1108:
PE
= Inline injection pump
S
= Flange mounted
6
= Number of cylinders
MW
= "MW" size pump
100
= Plunger diameter in 1/10 mm
/
= Pump model
320
= Number code for location of feed
pump and governor
R
= Rotation of pump as seen from drive
end (right hand clockwise)
S1108 = Application number
Figure 2. Injection Pump Identification
Each plunger has a delivery valve above the plunger.
The delivery valve, which is held on its seat by spring
pressure, prevents fuel from draining out of the high
pressure line between pumping cycles.
The injection cycle can be described by observing the
plunger in its four principle positions in the barrel. The
four positions are shown in Figure 3.
At bottom dead center the plunger is held down on the
lowest point of the cam lobe by the plunger spring. Top
of plunger is below the charging port of barrel. Fuel at
supply pump pressure flows through the charging port to
fill the area above the plunger.
Figure 3. Four Principle Plunger Positions of Injection
Cycle
1.
Bottom Dead Center
3.
Injection
2.
Port Closure
4.
End of Injection
Port closure begins when the rising plunger covers the
charging port and fuel is trapped above the plunger.
Start of injection occurs as the plunger continues with
charging ports covered, fuel is forced upward under high
pressure, unseats the delivery valve and is injected into
the cylinder.
End of injection occurs when the plunger moves up to
the point where the charging port is again uncovered by
the lower helix. Fuel pressure above the plunger is
relieved to the charging gallery. This pressure drop
allows delivery valve and injection nozzle to seat thus
ending injection.
CGES-375
Printed in United States of America
Page 2
