wsm wg972-e4, Workshop Manual

Page: 80 / 153

ENGINE
WG972-E4, WSM
1-M19
Primary Stage
Primary valve is pulled by primary valve spring at
normal condition and primary valve opens inlet of liquid
fuel.
Gaseous fuel fills in primary chamber and gas
pressure does not push down primary valve spring in
normal condition.
When the gaseous fuel pressure in primary chamber
got to be abnormal, the diaphragm swells by pressure in
primary chamber and push down the primary valve
spring through fulcrum point. Therefore primary valve is
closed and stop the inlet of liquid fuel.
Primary stage is safety device for abnormal gaseous
pressure.
9Y1211108ENM0035US0
Secondary Stage
Gaseous fuel fills in primary chamber, and then
gaseous fuel pushes up secondary valve and flows in
secondary chamber. Gaseous fuel flows out to mixer
from regulator after gaseous fuel was filled in secondary
chamber.
There is balance connection chamber on the
opposite side of secondary chamber through the
membrane secondary stage. This balance connection
chamber is connecting with mixer. Balance connection
chamber gets negative pressure by negative pressure
from mixer, and then membrane is pulled to the direction
of balance connection chamber. Then lever is pulled by
membrane, and also secondary valve moves to close
direction. Thus secondary stage is adjusting gaseous
fuel quantity flowing to the mixer.
9Y1211108ENM0036US0
(1) Inlet of Evaporator
(2) Primary Valve
(3) Primary Valve Spring
(4) Membrane Primary Stage
(5) Fulcrum Point of Membrane
Primary Stage
(6) Primary Chamber
(7) Outlet of Evaporator
A: Liquid Fuel In
(1) Balance Connection
Chamber
(2) Membrane Secondary Stage
(3) Secondary Chamber
(4) Lever
(5) Secondary Valve Spring
(6) Secondary Valve
(7) Fulcrum Point of Secondary
Valve
KiSC issued 07, 2015 A