Daewoo GC25E-3 Service Manual

G424 Service Manual LPG Fuel System(Low Emission Version)91
1. Fuel inlet
2. Primary valve
3. Primary spring
4. Primary heat exchanger chamber
5. Pressure transfer port
6. Primary diaphragm chamber
7. Secondary valve
8. Secondary spring
9. Primary diaphragm
10. Primary pivot
11. Primary pin
12. Coolant passage
13. Fuel outlet
14. Secondary vacuum chamber
15. Secondary diaphragm
16. Secondary atmospheric vent chamber
17. Secondary lever
18. Primary atmospheric chamber
Fuel (Propane Liquid), at tank pressure enters the
regulator through the fuel inlet port (1). Propane liquid
then flows through the primary valve (2), which is held
normally open by the primary spring (3), and into the
primary heat exchanger chamber of the regulator (4).
A small transfer port (5) connects the primary heat
exchanger chamber and the primary diaphragm
chamber(6).
The secondary valve (7) at the outlet of the primary
heat exchanger chamber (4) is held normally closed
by the secondary spring (8). Therefore the pressure in
the primary heat exchanger chamber (4) and the
primary diaphragm chamber (6) begins to rise from
atmospheric pressure. When the pressure in the
primary heat exchanger chamber (4) and primary
diaphragm chamber (6) reaches setting value it
causes a pressure/force imbalance across the primary
diaphragm (9) between the primary heat exchanger
chamber and the primary atmospheric chamber (18)
This causes the primary diaphragm and lever
assembly (9) to pivot (10) against primary spring (3)
pressure, raising primary valve pin (11), closing off the
primary valve (2). Since fuel pressure falls from tank
pressure, a liquid liquefied petroleum gas evaporates.
As this phase change occurs the fuel takes on heat
from the primary heat exchanger chamber of the
regulator (4). This heat is replaced by engine coolant,
which is piped through passage (12) in the heat
exchanger section of the regulator. Fuel will not flow
through the regulator to the carburetor until a negative
pressure signal is received. When the engine is
cranking or running, a negative pressure signal is
generated by the carburetor. This negative pressure
signal is communicated to the fuel outlet (13) and the
regulator secondary vacuum chamber (14). The
negative pressure signal acts upon the lower side of
the secondary diaphragm (15) causing a pressure /
force imbalance across the diaphragm between the
secondary vacuum chamber (14) and the secondary
atmospheric vent chamber (16). When the negative
pressure signal reaches negative setting value the
pressure force imbalance overcomes the secondary
spring force (8) and the secondary diaphragm (9)
moves downward. As the secondary diaphragm
moves it causes the secondary lever (l7) to pivot and
lift the secondary valve (7) off its seat allowing fuel to
flow from the primary heat exchanger chamber (4)
through the secondary chamber (14) and to the
carburetor. Since fuel has now exited the primary heat
exchanger chamber (4) the pressure in the chamber
will drop, allowing the primary valve (2) to re-open.
Whilst fuel is flowing, the calibrated secondary spring
(8) will maintain a relatively constant pressure in the
secondary vacuum chamber (14) and the amount of
fuel flowing will vary depending on how far the
secondary valve (7) opens in response to the negative
pressure signal generated by the carburetor.
For closed loop control, the secondary atmospheric
vent chamber (16) is connected to AVV via a fuel
control valve, thus varying the secondary vacuum
chamber pressure (14) in response to a pulse width
modulated signal provided to the fuel control valve.
12
11
15
14
16
17
13
7
1
2
10
18
8
9
6
3
5
LP Converter

Daewoo GC25E-3 Specifications

General

Brand	Daewoo
Model	GC25E-3
Category	Engine
Language	English