Toyota 8FDU15, Manual

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1-7
1. When starting the engine
When the ignition switch and LPG switch are both turned to ON, the LPG led from the IN port flows into chamber
A. Upon entering chamber A, the LPG pushes open the elastic face valve 1 by its own vapor pressure, and
enters the primary pressure reduction chamber B for pressure reduction and vaporization. When the pressure in
chamber B reaches in the range of 24.5 to 34.3 kPa (3.6 to 5.0 psi), first diaphragm pushes first regulator spring
to operate first valve lever by means of first diaphragm hook. As a result elastic face valve is closed and the
pressure in the primary pressure reduction chamber B remains at a constant level. When the starting motor runs,
the current flowing in the coil of the slow solenoid operates the valve to connect chambers B and D. Since the
pressure in chamber B at 24.5 to 34.3 kPa (3.6 to 5.0 psi) is higher than the atmospheric pressure, LPG flows
into chamber D. The LPG entering chamber D flows through the slow path, and main path into the adapter, and
is then supplied to the engine from the venturi nozzle to start initial explosion. When the throttle valve at the
electric governor is opened slightly then, vacuum is generated in the venturi of the adapter. The vacuum in the
adapter acts on the secondary pressure reduction chamber C via the main path. At this time, secondary
diaphragm is operated to open elastic face valve 2 via second valve lever to cause LPG to flow from the primary
pressure reduction chamber B to the secondary pressure reduction chamber C.
As a result, a large amount of LPG enters the adapter for consecutive combustion.
Slow path
Main path (to adaptor)
Elastic face valve 2
Chamber C
Secondary diaphragm
Second valve lever
Injector path
(to injector)
Chamber D
Slow solenoid valve
Chamber B
First diaphragm hook
First regulator spring
First diaphragm
First valve lever
Elastic face valve 1
Chamber A
IN port
01.book 7 ページ ２００７年２月２２日 木曜日 午後４時４６分
LPG Device for 4Y-E Engine
Section 1.3.1