Yanmar 4JH2E Service Manual page 112

Chapter 3 Fuel Injection Equipment
15. Injection Pump Construction and Operation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4JH2-UTE
Roller
Control sleeve
Cross coupling
Cam disk
Magnet valve
Distributor
head
Inlet port
Plunger barrel
Outlet port Delivery valve
Fig. 4 Cutaway view of fuel delivery
Speed Governing
Control lever
Control lever shaft
Ball joint
governor sleeve
Control sleeve Plunger
Fig. 5 Cutaway view of speed governing
Printed
in
Japan
AOA1029-9109SP
3-47
Because the plunger rotates and reciprocates
simultaneously, suction of the fuel oil into the
pressure chamber, pressurization in the pres-
sure chamber and delivery into the engine cyl-
inder are all possible.
The governor is located in the upper part of the
injection pump chamber. Four flyweights and a
governor sleeve are held in the flyweight hold-
er. which is mounted on the governor shaft.
The flyweight holder is rotated and accelerated
by the drive shaft gear. through rubber dam-
pers.
The governor lever assembly is supported by
pivot bolts in the pump housing. and the ball
joint at the bottom of the lever assembly is in-
serted into the control sleeve. which slides
over the outside surface of the plunger. The
top of the lever assembly ithe tension lever) is
connected to the governor spring by a retaining
pin. while the opposite end of the governor
spring is connected to the control lever shaft.
The control lever shaft is inserted into the gov-
ernor cover and a control lever is attached to
the control lever shaft. The accelerator pedal is
connected directly to the control lever by a link-
age. and the governor spring set force changes
in response to the control lever position (i.e.
accelerator pedal position).
Injection quantity control is governed by the
mutually opposing forces of the flyweights'
centrifugal force and the governor spring's set
force.
The flyweights' centrifugal force. which
changes in response to engine speed. acts on
the governor lever through the governor
sleeve.
The governor spring's set force. which is de-
pendant on control lever position. i.e. accelera-
tor pedal position. acts on the governor lever
through the retaining pin.