Yanmar 4LHA-DTP, Operation Manual

Page: 433 / 670

Chapter 3 Fuel Injection Equipment
1. Fuel Supply System
4LHA Series
1-6 Function o f Governor
(1) Function o f governor
The following is a representation of the movement
characteristics of the control rack at respective
speeds rising from 0, with the governor control
lever at the m a x i m u m speed position.
Max. control lever position
Low-idle control lever position
0
Cam speed
A - B : Fuel volume condition during starting. Volume is
controlled b y excess fuel spring.
B-C: The rack moves to decrease injection after the
engine starts and the speed increases, (as the load
of the excess fuel spring is overcome by the
centrifugal force of the governor weight).
C D: High torque at low speeds is obtained by increas-
ing the fuel injection volume in keeping with the
angleich stroke.
D-E:The condition when the thrust force exceeds the
force of the angleich spring on the bottom of the
tension lever. This gradually pushes the rack to
lower fuel injection as the engine speed increases.
E-F: The condition when both the right and left ends
of the shifter come in contact with the sleeve and
the bottom of the tension lever, and the control
rack is held in the normal position by the stopper,
(max. injection volume position on models not
equipped with an angleich spring).
F: The point at which the governor spring starts to
take effect. This is the rated output of the engine.
F': The point at which the governor starts to take
effect on models with a torque spring.
G : Continuous rating point (usually 8 5 - 9 0 % injec-
tion volume of F point).
H: N o load max. speed
L: Low-idle position
(2) Starting control
Moving the control lever to the m a x . speed posi-
tion pulls the governor spring, a n d moves the
tension lever until it comes in contact with the
control stopper. When this is done, the excess fuel
spring located between the tension lever and
governor lever holds t h e control rack at the max.
starting injection v o l u m e position R A - a .
After the engine is started, the excess fuel spring is
compressed as the centrifugal force of the governor
weight overcomes the set load of the excess fuel
spring. As the speed exceeds Nb, the speed changes
from B to C' (on m o d e l s with an angleich spring)
or B to C (on models without an angleich spring).
The rack reaches the position of R c , at which the
governor lever and tension lever are interlocked.
R A-B
Control lever positionjff^a
Rated speed settii
Full load stopper
Tension lever
Angleich spring assembly
Injection volume
Increase Decrease
Excess fuel spring
Shifter
E "
E _
to
c
o
"F
nb
(models with angleich spring)
/ _
nc
C a m speed
C'
3-2-11