Note: Descriptions are shown in the official language in which they were submitted.
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FUEL RESERVOIR
TYT-F058
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a fuel reserving
device and, in particular, a fuel tank connected to an
engine.
2. Description of the Related Art
A fuel reserving device or fuel tank should be
in communication with the outside air such that the
surface of the fuel can rise and fall in the fuel tank.
In the fuel tank, fuel vapor may be generated in a space
formed above the fuel surface. Therefore, the problem of
the discharge of fuel vapor from the fuel tank to the
outside air arises.
In a prior art, a fuel tank is in communication
with the outside air via a charcoal canister for
temporarily adsorbing fuel vapor thereon. The charcoal
canister must be large if the amount of the fuel vapor
generated in the fuel tank is large. To solve this
problem, unexamined Japanese patent publication -
No. 64-16426 discloses a fuel tank comprising an
inflatable airbag therein, the airbag being inflated or
deflated according to the change of the level of the fuel
surface to prevent a space being formed above the surface
of the fuel in the fuel tank.
However, in the fuel tank disclosed in the
above publication, the interior of the fuel tank is not
in communication with the outside air. Therefore, if a
space has been already formed above the fuel surface, the
space cannot be eliminated when the airbag is inflated.
Thus, fuel vapor may be generated in the space above the
fuel surface.
Therefore, the object of the invention is to
eliminate the space above the fuel surface, and the fuel
vapor therein, from the fuel reserving device.
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SUMMARY OF THE INVENTION
According to the invention, there is provided a fuel
reserving device for reserving fuel therein comprising:
a wall for dividing an interior of the device to a fuel
chamber and an air chamber, the wall being deformable
according to the amount of the fuel in the fuel chamber;
a discharge passage which is open to a space formed above
the surface of the fuel in the fuel chamber; a shut off
valve for normally shutting off the discharge passage;
gas discharging means for discharging gas from the space
via the discharge passage when the shut off valve is
open; and control means for controlling the gas
discharging means and the shut off valve to open the shut
off valve and operate the gas discharging means to
discharge the gas from the space when the amount of the
gas is larger than a predetermined amount, the control
means closing the shut off valve and stopping the
operation of the gas discharging means to stop the
discharging operation of the gas when the amount of the
gas is smaller than the predetermined amount.
Further, according to the invention, fuel surface
level detecting means is provided for detecting the level
of the surface of the fuel in the fuel chamber, and the
control means judges that the amount of the gas is larger
than the predetermined amount when the level of the
surface of the fuel detected by the fuel surface level
detecting means is lower than a predetermined level.
Further, according to the invention, fuel surface
level raising means is provided for raising the level of
the surface of the fuel, and the gas discharging means
controls the fuel surface level raising means to raise
the level of the surface of the fuel to discharge the gas
from the space when the amount of the gas is larger than
the predetermined amount.
Further, according to the invention, the fuel
surface level raising means feeds fuel to the fuel
chamber to raise the level of the surface of the fuel.
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Further, according to the invention, the fuel
surface level raising means deforms the wall to raise the
level of the surface of the fuel.
Further, according to the invention, the fuel
surface level raising means increases the pressure in the
air chamber to deform the wall.
Further, according to the invention, the fuel
surface level raising means increases the pressure in the
air chamber to a pressure lower than that of the fuel fed
to the fuel chamber when the feeding of the fuel to the
fuel chamber is stopped.
Further, according to the invention, the fuel
surface level raising means decreases the pressure in the
air chamber when the feeding of the fuel to the fuel
chamber is stopped.
Further, according to the invention, the fuel
surface level raising means introduces a negative
pressure into the space to deform the wall.
Further, according to the invention, the fuel
surface level raising means comprises a fuel pump for
pumping the fuel to generate a negative pressure by the
pumped fuel, and introduces the negative pressure into
the space via the discharging passage.
Further, according to the invention, the fuel
surface level raising means returns a portion of the fuel
pumped by the fuel pump into the fuel chamber to generate
the negative pressure.
Further, according to the invention, the fuel pump
is housed in a pump chamber connected to the fuel
chamber, the fuel surface level raising means returns the
portion of the fuel pumped by the fuel pump into the pump
chamber to generate the negative pressure and introduces
the negative pressure into a space formed above the
surface of the fuel in the pump chamber.
Further, according to the invention, the discharge
passage is connected to an air intake system of an
engine, and the fuel surface level raising means
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introduces the negative pressure in the air intake system
into the space formed above the surface of the fuel via
the discharge passage.
Further, according to the invention, the discharge
passage is connected to the air intake system via a
canister for adsorbing the fuel vapor thereon, and the
canister comprises a valve which opens to the atmosphere
when the pressure in the canister is under a
predetermined negative pressure to make the canister
communicate with the atmosphere.
Further, according to the invention, the fuel
surface level raising means raises the level of the
surface of the fuel when the engine can receive the fuel
vapor.
The present invention may be more fully understood
from the description of the preferred embodiments of the
invention set forth below, together with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a sectional view of a fuel reserving
device according to the first embodiment of the
invention;
Fig. 2 is a sectional view of the fuel reserving
device along the line II-II of the Fig. 1;
Fig. 3 is a sectional view of the fuel reserving
device immediately after the supply of the fuel into the
fuel chamber is stopped;
Fig. 4 is a sectional view of the fuel reserving
device when the fuel in the fuel chamber is decreased;
Fig. 5 is a sectional view of a fuel reserving
device according to the second embodiment of the
invention;
Fig. 6 is a flowchart of a fuel vapor eliminating
operation according to the second embodiment of the
invention;
Fig. 7 is a sectional view of a fuel reserving
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device according to the third embodiment of the
invention;
Fig. 8 is a flowchart of a fuel vapor eliminating
operation according to the third embodiment of the
invention;
Fig. 9 is a sectional view of a fuel reserving
device according to the fourth embodiment of the
invention;
Fig. 10 is a flowchart of a fuel vapor eliminating
operation according to the fourth embodiment of the
invention;
Fig. 11 is a sectional view of a fuel reserving
device according to the fifth embodiment of the
invention;
Fig. 12 is a flowchart of a fuel vapor eliminating
operation according to the fifth embodiment of the
invention;
Fig. 13 is a sectional view of a fuel reserving
device according to the sixth embodiment of the
invention;
Fig. 14 is a sectional view of a fuel reserving
device according to the seventh embodiment of the
invention;
Fig. 15 is a flowchart of a fuel vapor eliminating
operation according to the seventh embodiment of the
invention;
Fig. 16 is a sectional view of a fuel reserving
device according to the eighth embodiment of the
invention;
Fig. 17 is a flowchart of a fuel vapor eliminating
operation according to the eighth embodiment of the
invention;
Fig. 18 is a sectional view of a fuel reserving
device according to the ninth embodiment of the
invention;
Fig. 19 is a flowchart of a fuel vapor eliminating
operation according to the ninth embodiment of the
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invention;
Fig. 20 is a sectional view of a fuel reserving
device according to the tenth embodiment of the
invention;
Fig. 21 is a part of a flowchart of a fuel vapor
eliminating operation according to the tenth embodiment
of the invention;
Fig. 22 is a part of a flowchart of a fuel vapor
eliminating operation according to the tenth embodiment
of the invention;
Fig. 23 is a sectional view of a fuel reserving
device according to the eleventh embodiment of the
invention;
Fig. 24 is a sectional view of a fuel reserving
device according to the twelfth embodiment of the
invention;
Fig. 25 is a sectional view of a fuel reserving
device according to the thirteenth embodiment of the
invention;
Fig. 26 is a part of a flowchart of a fuel vapor
eliminating operation according to the thirteenth
embodiment of the invention;
Fig. 27 is a part of a flowchart of a fuel vapor
eliminating operation according to the thirteenth
embodiment of the invention;
Fig. 28 is a partial sectional view of a fuel
reserving device according to the fourteenth embodiment
of the invention;
Fig. 29 is a perspective view of the fuel reservoir
according to the fourteenth embodiment of the invention;
Fig. 30 is a perspective view of the fuel reservoir
in the expanded state;
Fig. 31 is a perspective view of the fuel reservoir
in the deflated state;
Fig. 32 is a partial sectional view of a fuel pump
device according to the fourteenth embodiment of the
invention;
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Fig. 33 is a partial sectional view of the fuel pump
device along line XXXIII-XXXIII in Fig. 32;
Fig. 34 is a partial sectional view of another fuel
pump device different from that according to the
fourteenth embodiment of the invention;
Fig. 35 is a partial sectional view of a fuel pump
device according to the fifteenth embodiment of the
invention; and
Fig. 36 is a partial sectional view of the fuel pump
device along line XXXVI-XXXVI in Fig. 35.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A fuel reserving device according to the first
embodiment of the invention will be explained below. For
example, the fuel reserving device is mounted on a
vehicle to reserve fuel to be fed to an engine. However,
the fuel reserving device can be used to just reserve
fuel for a certain period.
As shown in Fig. 1, a fuel tank 1 of the fuel
reserving device comprises upper and lower portions 2 and
3 comprised of a material such as metal or a synthetic
resin. The upper and lower portions 2 and 3 are
sealingly connected to each other at the peripheral
flange portions 2a and 3a thereof.
A separating wall or sheet 5 is positioned within an
interior 4 defined by the upper and lower portions 2 and
3. The wall 5 separates the interior 4 into an air
chamber 6 located above the wall 5 and a fuel chamber 7
located under the wall 5. The wall 5 is made of a
material having flexibility and vapor-impermeability such
as polyethylene or nylon. The wall 5 is attached to an
anchor portion 8 at a peripheral portion 5a thereof.
That is, the wall 5 is sealingly attached to an inner
wall face of the fuel tank 1. The peripheral portion 5a
of the wall 5 is clipped between the peripheral flange
portions 2a and 3a of the upper and lower portions 2 and
3.
The wall 5 comprises annular folded portions 5b
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therein which are generally concentrically positioned and
are equally spaced from each other. Therefore, the
wall 5 has a wave shaped portion defined by the annular
folded portions 5b. The wall 5 can be bent at the folded
portions 5b. Therefore, a central portion 5c of the
wall 5 can be moved up and down in the tank 1. Thus, the
separating wall 5 is deformed at the folded portion 5b
wherein the central portion 5c is moved up and down.
A fuel feeding pipe 13 is sealingly connected to the
lower portion 3, and is open to the interior of the fuel
chamber 7. A cap 14 for closing the pipe 13 is removably
attached on an upper opening 13a of the pipe 13. A seal
member 15 which comes into contact with an outer
peripheral face of the cap 14 when the cap 14 is attached
on the opening 13a, a seal member 16 which comes into
contact with an outer peripheral face of a fuel filling
nozzle when the nozzle is inserted into the pipe 13 to
fill the fuel chamber 7 with fuel, and a fuel vapor shut
off valve 17 which normally shuts off the pipe 13 by a
spring force are provided in the pipe 13 adjacent to the
opening 13a.
On the other hand, a check valve 10 is provided in a
lower opening 13b of the fuel feeding pipe 13. The
valve 10 is opened by the pressure of the fuel supplied
from the fuel filling nozzle, and is closed by the
pressure of the fuel in the fuel chamber 7.
A fuel pump chamber 18 is connected to the fuel
chamber 7. The fuel pump chamber 18 is defined by the
lower portion 3 and projects outward from the peripheral
flange portion 2a of the upper portion 2.
A fuel pump 19, a pressure regulator 20 and a fuel
filter 21 are positioned in the fuel pump chamber 18.
The pressure of the fuel pumped by the pump 19 is
regulated by the regulator 20, and thereafter, the fuel
is fed to fuel injectors (not shown) via a fuel feeding
pipe 22. It is not necessary to provide any fuel return
passages which return the fuel to the fuel tank 1 from a
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fuel dispensing pipe for dispensing the fuel from the
fuel feeding pipe 22 to each injector since the
regulator 20 returns the fuel to the fuel pump chamber 18
connected to the fuel chamber 7. Therefore, the fuel,
which is heated adjacent to a cylinder head of the engine
and includes fuel vapor therein, is not be returned into
the fuel chamber 7. Thus, the generation of the fuel
vapor in the fuel chamber 7 is prevented. Further, the
transmission of the noise of the pump 19 from the fuel
tank 1 to the outside of the tank 1 is prevented since
the pump 19 is positioned in the fuel tank 1.
The fuel chamber 7 is connected to the fuel feeding
pipe 13 via a circulation pipe 23. The pipe 23 is
connected to the lower portion 3, and is open to the
interior of the fuel chamber 7 above the lower
opening 13b of the fuel feeding pipe 13 and immediately
under the anchor portion 8. The circulation pipe 23
relieves air from the fuel chamber 7 to the fuel feeding
pipe 13 when the fuel is supplied into the fuel chamber 7
via the fuel feeding pipe 13. Therefore, the supply of
the fuel into the fuel chamber 7 is easily carried out.
A first shut off valve 30 is attached to an opening
of the circulation pipe 23 which is open to the interior
of the fuel chamber 7. The valve 30 is closed by the
fuel which reaches the valve 30. Therefore, when the
valve 30 is closed, the pressure in the fuel feeding
pipe 13 adjacent to the opening of the circulation
pipe 23 which is open to the interior of the fuel feeding
pipe 13 is decreased.
An upper space 18a in the fuel pump chamber 18 is in
communication with the interior of the fuel feeding
pipe 13 via a fuel vapor discharging pipe 24. The
pipe 24 is connected to an upper wall portion defining
the fuel pump chamber 18. The pipe 24 relieves air from
the fuel chamber 7 to the fuel feeding pipe 13 when the
fuel is supplied into the fuel chamber 7 via the fuel
feeding pipe 13. Therefore, the supply of the fuel into
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the fuel chamber 7 is easily carried out.
A second shut off valve 31 is attached to an opening
of the fuel vapor discharging pipe 24 which is open to
the interior of the fuel pump chamber 18. The valve 31
is closed by the fuel which reaches the valve 31.
Therefore, when the valve 31 is closed, the pressure in
the fuel feeding pipe 13 adjacent to the opening of the
fuel vapor discharging pipe 24, which is open to the
interior of the fuel feeding pipe 13, is decreased. The
opening of the fuel vapor discharging pipe 24 which is
open to the interior of the fuel feeding pipe 13 is
located above the opening of the circulation pipe 23
which is open to the interior of the fuel feeding
pipe 13.
The fuel feeding pipe 13 is connected to a charcoal
canister 26 via a first fuel vapor purging pipe 25. An
opening of the pipe 25 which is open to the interior of
the fuel feeding pipe 13 is located at the level equal to
the opening of the fuel vapor discharging pipe 24 which
is open to the interior of the fuel feeding pipe 13.
The charcoal canister 26 comprises an activated
carbon 26a therein for adsorbing fuel vapor thereon. The
canister 26 is open to the outside air via an atmosphere
relief pipe 28. Further, the canister 26 is connected to
an intake passage (not shown) of the engine via a second
fuel vapor purging pipe 27.
Fuel vapor generated in the fuel chamber 7, the fuel
feeding pipe 13 and fuel pump chamber 18 is introduced
into the charcoal canister 26 via the circulation
pipe 23, the fuel vapor discharging pipe 24 and the first
fuel vapor purging pipe 25, and is adsorbed on the
activated carbon 26a. Therefore, the discharging of the
fuel vapor to the outside air is prevented. The fuel
vapor adsorbed on the activated carbon 26a is purged into
the intake passage via the second fuel vapor purging
pipe 27 on the basis of an engine driving condition such
as an engine load.
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For example, the separating wall 5 is moved, by the
movement of the fuel in the fuel chamber 7, when the
vehicle with the fuel tank 1 is turned. Therefore, a
large load such as a stress is generated in the wall 5.
In the first embodiment, as shown in Fig. 2, an inner
wall face of a side wall 3b of the lower portion 3 is
inclined inwardly from the anchor portion 8 to a bottom
wall 3c of the lower portion 3. The shape of the inner
wall face of the side wall 3b corresponds to the shape of
the wave shaped portion defined by the folded portions 5b
when the central portion 5c is located at the lower area
in the fuel chamber 7. Therefore, the horizontal and
vertical movement of the wave shaped portion of the
wall 5, and a movement of the wall 5 are prevented,
independently of the position of the central portion 5c
of the wall 5 in the fuel chamber 7.
Annular projections 29 are formed on the inner wall
face of the side wall 3b of the lower portion 3. The
projections 29 project inwardly from the side wall 3b so
that the side wall 3b has steps thereon. The wave shape
portion including the folded portions 5b comes smoothly
into contact with the projections 29. Therefore, the
horizontal and vertical movement of the wave shape
portion of the wall 5, and a movement of the wall 5 are
prevented.
The projections 29 are formed on the side wall 3b
from the anchor portion 8 to the bottom wall 3c so that
recesses are formed between the adjacent projections 29.
The recesses hold the folded portions 5b so that the
horizontal and vertical movement of the wave shape
portion of the wall 5, and a movement of the wall 5 are
further prevented.
As described above, the generation of the large
stress in the wall 5 is prevented so that the damage of
the wall 5 is avoided.
Further, the projections 29 decrease the air volume
formed between the fuel surface and the wall 5 so that
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the amount of the fuel vapor generated in the fuel
chamber 7 is decreased. Further, the projections 29
reinforce the lower portion 3 so that there is no need to
provide any reinforcing member to reinforce the lower
portion 3.
Springs 32 as biasing or resilient means are
attached to an inner wall face of the upper portion 2 of
the fuel tank 1. The springs 32 extend downwardly from
the inner wall face of the upper portion 2. The
springs 32 abut against the central portion 5c of the
wall 5 when the central portion 5c is moved up.
Therefore, the bumping of the wall 5 into the inner wall
face of the upper portion 2 is prevented.
The air chamber 6 is in communication with the
outside air via a pipe 33 which is open to the
atmosphere. The pipe 33 is connected to the upper
portion 2 of the fuel tank 1. The pipe 33 relieves air
from the air chamber 6 to the outside air when the
central portion 5c of the wall 5 is moved up. Therefore,
the central portion 5c is easily moved up when the fuel
is supplied into the fuel chamber 7. On the other hand,
the pipe 33 introduces air from the outside air to the
air chamber 6 when the central portion 5c of the wall 5
is moved down. Therefore, the central portion 5c is
easily moved down when the fuel in the fuel chamber 7 is
used during the driving of the engine.
An operation of eliminating the fuel vapor from the
space above the fuel surface in the fuel chamber 7, i.e.,
the space between the fuel surface in the fuel chamber
and the wall 5 (hereinafter, referring to as "fuel vapor
eliminating operation") according to the first embodiment
of the invention will be explained below.
In the first embodiment, when there is a space above
the fuel surface in the fuel chamber 7, fuel is supplied
to the fuel chamber 7. The level of the fuel surface is
raised by the supply of the fuel into the fuel chamber 7.
Therefore, the fuel vapor in the space above the fuel
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surface is discharged therefrom to the fuel feeding
pipe 13 via the circulation and fuel vapor discharging
pipes 23 and 24.
The fuel chamber 7 is sealed when the fuel surface
reaches the first and second shut off valves 30 and 31,
i.e., when the fuel vapor in the space above the fuel
surface is completely eliminated therefrom. Then, the
supply of the fuel into the fuel chamber 7 is stopped.
Once the fuel chamber 7 is sealed, the sealing of the
fuel chamber 7 is maintained so that no spaces can be
formed above the fuel surface in the fuel chamber 7.
Thus, the generation of the fuel vapor in the fuel
chamber 7 is prevented. In the first embodiment, the
supply of the fuel into the fuel chamber 7 corresponds to
means for discharging gas from the space formed above the
fuel surface or for raising the level of the fuel
surface.
The fuel vapor eliminating operation according to
the first embodiment will be explained below by referring
to Figures.
Fig. 1 shows the fuel tank 1 including the fuel
vapor therein. Before starting the supply of the fuel
into the fuel chamber 7, the cap 14 is removed from the
upper opening 13a of the fuel feeding pipe 13. When the
cap 14 is removed, the fuel vapor shut off valve 17 is
closed. Therefore, the discharging of the fuel vapor
from the upper opening 13a to the outside air is
prevented.
Next, a fuel filling nozzle (not shown) is inserted
into the upper opening 13a of the fuel feeding pipe 13.
The nozzle opens the fuel vapor shut off valve 17 against
the biasing force, and then, the outer peripheral face of
the nozzle comes into contact with the seal member 16.
Therefore, when the nozzle is inserted into the fuel
feeding pipe 13, the discharging of the fuel vapor from
the upper opening 13a to the outside air is prevented.
Next, the fuel is supplied from the nozzle into the
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fuel chamber 7 via the fuel feeding pipe 13. The level
of the fuel surface in the fuel chamber 7 is raised as
the amount of the fuel in the fuel chamber 7 is
increased. Therefore, the wall 5 is moved up.
When the level of the fuel surface is raised, the
fuel vapor in the space above the fuel surface is
discharged from the fuel chamber 7 to the fuel feeding
pipe 13 via the circulation and fuel vapor discharging
pipes 23 and 24. The wall 5 is kept in sealing contact
with the fuel surface when the level of the fuel surface
is raised. Therefore, the amount of the fuel vapor
generated in the fuel chamber 7 when the fuel is supplied
thereinto is kept small.
The first shut off valve 30 is closed by the fuel in
the fuel chamber 7 to shut off the circulation pipe 23
when the fuel surface reaches the valve 30. Thereafter,
the upward movement of the central portion 5c of the
wall 5 is restricted by the springs 32. Thereafter, as
shown in Fig. 3, the second shut off valve 31 is closed
by the fuel in the fuel chamber 7 to shut off the fuel
vapor discharging pipe 24 when the fuel surface reaches
the valve 31. Therefore, the fuel vapor in the space
above the fuel surface is completely eliminated from the
fuel chamber 7 and the fuel tank 1.
The pressure in the fuel feeding pipe 13 is
decreased to under a predetermined pressure when the
first and second shut off valves 30 and 31 are closed.
When a pressure sensor in the nozzle senses that the
decreased pressure is lower than the predetermined
pressure, the supply of the fuel into the fuel chamber 7
is stopped. Then, the pressure of the fuel in the fuel
chamber 7 becomes higher than that of the fuel in the
fuel feeding pipe 13. Therefore, the check valve 10 is
closed by the fuel in the fuel chamber 7. Thus, the fuel
chamber 7 is completely sealed while there is no fuel
vapor in the fuel chamber 7.
Next, the nozzle is withdrawn from the upper
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opening 13a of the fuel feeding pipe 13 and, then, the
fuel vapor shut off valve 17 is closed by the spring
force. Finally, the cap 14 is attached to the upper
opening 13a of the fuel feeding pipe 13.
An operation of the fuel tank 1 during the driving
of the engine according to the first embodiment will be
explained below.
During the driving of the engine, the amount of the
fuel in the fuel chamber 7 is decreased. Therefore, the
level of the fuel surface in the fuel chamber 7 is
lowered and the central portion 5c of the wall 5 is moved
down. As shown in Fig. 4, the wall 5 projects downwardly
into the fuel chamber 7. When the wall 5 is moved down,
since the fuel chamber 7 is sealed, no spaces can be
formed above the fuel surface. Therefore, once the fuel
vapor eliminating operation is carried out, the
generation of the fuel vapor in the fuel chamber 7 is
prevented. Thus, only a small, or no, charcoal canister
most to be provided in the fuel reserving device.
In the first embodiment, the first and second shut
off valves 30 and 31 may open when the fuel moves in the
fuel chamber 7. Therefore, a space may be formed above
the fuel surface in the fuel chamber 7, and fuel vapor
may be generated therein even when the engine is driven.
Therefore, according to the second embodiment, fuel vapor
is eliminated by a method other than the supply of the
fuel into the fuel chamber 7.
A fuel reserving device according to the second
embodiment of the invention will be explained below.
In the second embodiment, as shown in Fig. 5, an air
pump 35 is connected to the air chamber 6 via a first
connection pipe 34 instead of the atmosphere pipe 33 of
the first embodiment. The pump 35 serves to increase the
pressure in the air chamber 6.
The first connection pipe 34 is connected to a
relief valve 37 via a second connection pipe 36. The
valve 37 opens to decrease the pressure in the air
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chamber 6 when the pressure in the air chamber 6 becomes
higher than a predetermined pressure. The predetermined
pressure is lower than that which may damage the wall 5.
A small hole 39 is formed in a diaphragm 38 of the
relief valve 37. The hole 39 puts the second connection
pipe 36 in communication with the outside air,
independently of the opening or closing of the relief
valve 37. The diameter of the hole 39 is arranged to not
prevent the air pump 35 from increasing the pressure in
the air chamber 6.
A level switch 57 is mounted on the upper wall of
the fuel pump chamber 18 at the highest position in the
fuel tank 1. The switch 57 outputs a voltage when the
fuel surface reaches the switch 57, i.e., when the fuel
surface reaches the highest position in the fuel tank 1.
The fuel reserving device comprises an electronic
control unit 40. The unit 40 is a digital computer and
is provided with a CPU (microprocessor) 42, a RAM (random
access memory) 43, a ROM (read only memory) 44, a B-RAM
(backup-RAM) 45, an input port 46 and an output port 47,
which are interconnected by a bidirectional bus 41.
A voltage generated in the level switch 57 when the
fuel surface reaches the switch 57 is input into the
input port 46 via a corresponding AD converter 48. A
voltage representing the opening or closing of the relief
valve 37 is input into the input port 46 via a
corresponding AD converter 48. The output port 47 is
connected to the air pump 35 via a drive circuit 49.
Components other than those described above are the
same as those of the fuel reserving device according to
the first embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
second embodiment will be explained below.
In the second embodiment, it is judged if the relief
valve 37 is open. When the relief valve 37 is closed, it
is judged that the pressure in the air chamber 6 allows
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the fuel vapor eliminating operation.
Further, in the second embodiment, it is judged if
the level switch 57 is on. When the level switch 57 is
off, it is judged that the fuel vapor eliminating
operation should be carried out.
When it is judged that the relief valve 37 is closed
and the level switch 57 is off, the air pump 35 is
activated to increase the pressure in the air chamber 6.
Therefore, the central portion 5c of the wall 5 is moved
down toward the bottom wall 3c of the lower portion 3.
Thus, the level of the fuel surface forming a space
thereabove is raised. When the level of the fuel surface
is raised, the fuel vapor is discharged from the fuel
chamber 7 to the fuel feeding pipe 13 via the circulation
and fuel vapor discharging pipes 23 and 24.
When it is judged that the pressure in the air
chamber 6 does not allow the fuel vapor eliminating
operation, the air pump 35 is stopped.
In the second embodiment, the air pump 35
corresponds to means for discharging gas from the space
formed above the fuel surface or for raising the level of
the fuel surface, and the level switch 57 corresponds to
means for detecting the fuel surface.
The fuel vapor eliminating operation according to
the second embodiment will be explained below by
referring to a flowchart in Fig. 6.
At step 210, it is judged if the level switch 57 is
on. When the switch 57 is on, it is judged that the fuel
vapor eliminating operation cannot be carried out, the
routine proceeds to step 212 where the air pump 35 is
stopped, and the routine is ended. On the other hand,
when the switch 57 is off, it is judged that the fuel
vapor eliminating operation can be carried out, and the
routine proceeds to step 214.
At step 214, it is judged if the relief valve 37 is
open. When the valve 37 is open, it is judged that the
fuel vapor eliminating operation cannot be carried out,
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the routine proceeds to step 212 where the air pump 35 is
stopped, and the routine is ended. On the other hand,
when the valve 37 is closed, it is judged that the fuel
vapor eliminating operation should be carried out, the
routine proceeds to step 216 where the air pump 35 is
activated to increase the pressure in the air chamber 6
for eliminating the fuel vapor from the fuel chamber 7,
and the routine is ended.
In the first embodiment, in order to completely
eliminate the fuel vapor from the fuel tank, it is
necessary to fill the fuel tank with fuel until the tank
is full with the fuel. Therefore, if the supply of the
fuel into the fuel chamber 7 is stopped before the tank
is full with the fuel, the fuel vapor cannot be
completely eliminated from the fuel chamber 7. In the
third embodiment, even if the supply of the fuel into the
fuel chamber is stopped before the fuel chamber is full
with the fuel, the fuel vapor is completely eliminated
from the fuel chamber.
A fuel reserving device according to the third
embodiment of the invention will be explained below.
In the third embodiment, as shown in Fig. 7, the
fuel tank 1 comprises a cap closure opener switch 50.
The opener switch 50 is connected to a cap closure (not
shown) for covering the cap 14. The opener switch 50 is
activated to output a voltage when the cap closure is
opened, and continues to output the voltage until the cap
closure is closed. Therefore, it can be judged if the
fuel is now supplied by detecting the voltage in the
opener switch 50. The voltage generated in the opener
switch 50 is input into the input port 46 via a
corresponding AD converter 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the second embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
' ~ CA 02301030 2000-02-15
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third embodiment will be explained below.
In the third embodiment, it is judged if the relief
valve 37 is open. When the valve 37 is closed, it is
judged that the pressure in the air chamber 6 allows the
fuel vapor eliminating operation.
Further, it is judged if the cap closure opener
switch 50 is on and the level switch 57 is off. When the
opener switch 50 is on and the level switch 57 is off, it
is judged that the fuel vapor eliminating operation
should be carried out.
When the pressure in the air chamber 6 does not
allow the fuel vapor eliminating operation, and no fuel
vapor eliminating operation needs to be carried out, the
opening of the cap closure is allowed to start the supply
of the fuel into the fuel chamber 7.
On the other hand, when the pressure in the air
chamber 6 allows the fuel vapor eliminating operation,
and the fuel vapor eliminating operation should be
carried out, the air pump 35 is activated to increase the
pressure in the air chamber 6. Therefore, the central
portion 5c of the wall 5 is moved down. Thus, the fuel
vapor above the fuel surface is discharged from the
tank 1 to the fuel feeding pipe 13 via the circulation
and fuel vapor discharging pipes 23 and 24.
Thereafter, when the pressure in the air chamber 6
does not allow the fuel vapor eliminating operation, or
no fuel vapor eliminating operation needs to be carried
out, the air pump is stopped and the opening of the cap
closure is allowed to start the supply of the fuel into
the fuel chamber 7.
Therefore, the air pump 35 corresponds to means for
discharging gas from the space formed above the fuel
surface or for raising the level of the fuel surface, and
the level switch 57 corresponds to means for detecting
the level of the fuel surface.
According to the third embodiment, when the supply
of the fuel into the fuel chamber 7 is started, the level
~
CA 02301030 2000-02-15
- 20 -
of the fuel surface is raised to the higher level.
Therefore, the amount of the fuel to be supplied to raise
the level of the fuel surface to the highest level in the
fuel chamber 7 is smaller than that in the first
embodiment. Thus, according to the third embodiment, the
fuel vapor can be completely eliminated from the fuel
chamber 7 even if the supply of the fuel into the fuel
chamber 7 is stopped before the fuel chamber is full with
the fuel.
Note that the fuel feeding nozzle used to feed the
fuel into the fuel chamber in the third embodiment stops
feeding the fuel when the nozzle detects that the level
of the fuel in the fuel feeding pipe 13 exceeds a
predetermined level. The predetermined level is lower
than the opening of the circulation pipe 23 which is open
to the interior of the fuel feeding pipe 13.
The fuel vapor eliminating operation according to
the third embodiment will be explained below by referring
to a flowchart in Fig. 8.
At step 310, it is judged if the cap closure opener
switch 50 is on. When the opener switch 50 is on, the
routine proceeds to step 312. On the other hand, when
the opener switch 50 is off, the routine proceeds to
step 318 where the air pump 35 is stopped, and the
routine is ended.
At step 312, it is judged if the level switch 57 is
on. When the level switch 57 is on, it is judged that no
fuel vapor eliminating operation needs to be carried out,
the routine proceeds to step 314 where the air pump 35 is
stopped, the routine proceeds to step 316 where the
opening of the cap closure is allowed, and the routine is
ended. On the other hand, when the level switch 57 is
off, the routine proceeds to step 320.
At step 320, it is judged if the relief valve 37 is
open. When the valve 37 is open, it is judged that the
fuel vapor eliminating operation cannot be carried out,
the routine proceeds to step 314 where the air pump 35 is
CA 02301030 2000-02-15
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stopped, the routine proceeds to step 316 where the
opening of the cap closure is allowed, and the routine is
ended. On the other hand, when the valve 37 is closed,
it is judged that the fuel vapor eliminating operation
can be carried out, the routine proceeds to step 322
where the air pump 35 is activated to increase the
pressure in the air chamber 6, and the routine is ended.
In the second embodiment, the air pump 35 and the
relief valve 37 are used to carry out the fuel vapor
eliminating operation. Therefore, the structure of the
fuel reserving device is complicated and the cost for
manufacturing the fuel reserving device is increased.
According to the fourth embodiment, the fuel vapor
eliminating operation is carried out with a simpler
structure.
A fuel reserving device according to the fourth
embodiment will be explained below.
In the fourth embodiment, as shown in Fig. 9, the
air pump 35, the relief valve 37 and the first and second
connection pipes 34 and 36 of the second embodiment are
deleted, and an atmosphere pipe 33 is connected to the
upper portion 2 of the fuel tank 1.
The charcoal canister 26 of the second embodiment is
deleted, and an electromagnetic valve 51 is connected to
the first and second fuel vapor purging pipes 25 and 27.
The fuel feeding pipe 13 is connected to the intake
passage 52 via the first and second fuel vapor purging
pipes 25 and 27 and the electromagnetic valve 51. The
electromagnetic valve 51 shuts off the communication
between the fuel feeding pipe 13 and the intake
passage 52.
The fuel reserving device comprises a temperature
sensor 55 for generating a voltage corresponding to the
temperature of the cooling water for cooling the engine.
The temperature sensor 55 is connected to the input
port 46 via a corresponding AD converter 48. The output
port 47 is connected to the electromagnetic valve 51 via
' ~ CA 02301030 2000-02-15
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the driving circuit 49.
Components other than those described above are the
same as those of the fuel reserving device according to
the second embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
fourth embodiment will be explained below.
In the fourth embodiment, it is judged if the
temperature of the cooling water is higher than a
predetermined temperature (for example, 70°C). The
predetermined temperature is higher than that of the
cooling water when the cooling water cools the engine in
the constant driving condition. When the temperature of
the cooling water is higher than the predetermined
temperature, the driving condition of the engine allows
the fuel vapor eliminating operation.
Further, in the fourth embodiment, it is judged if
the level switch 57 is on. When the switch 57 is off, it
is judged that the fuel vapor eliminating operation
should be carried out.
When the driving condition of the engine allows the
fuel vapor eliminating operation, and the fuel vapor
eliminating operation should be carried out, the
electromagnetic valve 51 is opened to introduce the
negative pressure in the intake passage 52 to the fuel
chamber 7. The introduced negative pressure discharges
the fuel vapor from the fuel chamber 7, moves the central
portion 5c of the wall 5 down, and raises the level of
the fuel surface.
When the driving condition of the engine does not
allow the fuel vapor eliminating operation, or no fuel
vapor eliminating operation needs to be carried out, the
electromagnetic valve 51 is closed.
Therefore, according to the fourth embodiment, the
simpler structure of the fuel reserving device without
the air pump and the relief valve can eliminate the fuel
vapor from the fuel chamber. In the fourth embodiment,
' ~ CA 02301030 2000-02-15
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the purging of the fuel vapor from the fuel chamber to
the intake passage corresponds to means for discharging
gas from the space formed above the fuel surface or for
raising the level of the fuel surface, and the level
switch 57 corresponds to means for detecting the level of
the fuel surface.
Further, in the fourth embodiment, the fuel vapor
eliminating operation may be controlled on the basis of
the engine speed, or the engine load, or the amount of
the air introduced into combustion chambers of the
engine, or the condition of the combustion in the
combustion chambers. For example, when the engine speed,
or the engine load or the amount of the air introduced
into the combustion chambers is lower than a
predetermined value, or when combustion is in the
stratified condition, the fuel vapor eliminating
operation is stopped.
The fuel vapor eliminating operation according to
the fourth embodiment will be explained below by
referring to a flowchart in Fig. 10.
At step 410, it is judged if the level switch 57 is
on. When the switch 57 is on, it is judged that no fuel
vapor eliminating operation needs to be carried out, the
routine proceeds to step 412 where the electromagnetic
valve 51 is closed, and the routine is ended. On the
other hand, when the switch 57 is off, the routine
proceeds to step 414.
At step 414, it is judged if the temperature T of
the cooling water is higher than the predetermined
temperature TO (T > TO). When T > T0, it is judged that
the driving condition of the engine allows the fuel vapor
eliminating operation, the routine proceeds to step 416
where the electromagnetic valve 51 is opened, and the
routine is ended. On the other hand, when T < T0, the
driving condition of the engine does not allow the fuel
vapor eliminating operation, the routine proceeds to
step 412 where the electromagnetic valve 51 is closed,
CA 02301030 2000-02-15
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and the routine is ended.
In the fourth embodiment, in the case that a
charcoal canister should be provided to the fuel
reserving device, the canister may be provided on the
first fuel vapor purging pipe 25 between the fuel feeding
pipe 13 and the electromagnetic valve 51. The canister
may be in communication with the outside air to avoid an
excess decrease in the pressure in the canister when the
electromagnetic valve 51 is opened, and to avoid an
excess increase in the pressure in the fuel chamber 7
when the electromagnetic valve 51 is closed. Therefore,
in the case that the fuel reserving device according to
the fourth embodiment comprises a charcoal canister, the
negative pressure cannot be introduced into the fuel
chamber 7 because of the communication of the canister
with the outside air so that the fuel vapor in the fuel
chamber 7 cannot be eliminated. According to the fifth
embodiment, the negative pressure can be introduced into
the fuel chamber 7 even if the fuel reserving device
comprises a charcoal canister.
A fuel reserving device according to the fifth
embodiment of the invention will be explained below.
In the fifth embodiment, as shown in Fig. 11, a
charcoal canister 26 is provided on the first fuel vapor
purging pipe 25 between the fuel feeding pipe 13 and the
electromagnetic valve 51. The canister 26 is in
communication with the outside air via an atmosphere
relief pipe 28.
A control valve 58 for shutting off the atmosphere
relief pipe 28 is provided on the pipe 28. The valve 58
is constituted by positive and negative valves. Further,
the valve 58 is opened at a predetermined positive
pressure to decrease the pressure in the canister 26, and
is closed at a predetermined negative pressure to
increase the pressure in the canister 26. The
predetermined positive pressure is lower than that which
the fuel tank 1, the charcoal canister 26, the components
CA 02301030 2000-02-15
- 25 -
related thereto, and the wall 5 can withstand, or the
fuel vapor cannot discharge from the tank 1, the
canister 26 or the components related thereto. The
predetermined negative pressure is higher than that which
the fuel tank 1, the charcoal canister 26, the components
related thereto, and the wall 5 can withstand.
Components other than those described above are the
same as those of the fuel reserving device according to
the fourth embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
fifth embodiment will be explained below.
In fifth embodiment, it is judged if the temperature
of the cooling water is higher than the predetermined
temperature. When the temperature of the cooling water
is higher than the predetermined temperature, it is
judged that the temperature of the cooling water allows
the fuel vapor eliminating operation. The predetermined
temperature is higher than that of the cooling water when
the cooling water cools the engine in the constant
driving condition.
Further, in the fifth embodiment, it is judged if
the level switch 57 is on. When the level switch 57 is
off, it is judged that the fuel vapor eliminating
operation should be carried out.
When it is judged that the temperature of the
cooling water allows the fuel vapor eliminating
operation, and the fuel vapor eliminating operation
should be carried out, the electromagnetic valve 51 is
opened to introduce the negative pressure in the intake
passage 52 into the canister 26 via the second fuel vapor
purging pipe 27. When the negative pressure is
introduced into the canister 26, the pressure in the
canister 26 is lower than the predetermined positive
pressure and is higher than the predetermined negative
pressure because of the action of the control valve 58.
Of course, when the pressure in the canister 26 becomes
' ~ CA 02301030 2000-02-15
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lower than the predetermined negative pressure, the
control valve 58 is opened, and the negative pressure
lower than the predetermined negative pressure cannot be
introduced into the fuel chamber 7, i.e., only the
negative pressure higher than the predetermined negative
pressure can be introduced into the fuel chamber 7.
Therefore, the negative pressure in the intake passage 52
is introduced into the fuel chamber 7 via the first fuel
vapor purging pipe 25, the circulation pipe 23 and the
fuel vapor discharging pipe 24. Thus, according to the
fifth embodiment, in the fuel tank with the charcoal
canister, the negative pressure in the intake passage can
be introduced into the fuel chamber 7 to eliminate the
fuel vapor above the fuel surface.
In the fifth embodiment, the purging of the fuel
vapor from the fuel chamber to the intake passage
corresponds to means for discharging gas from the space
formed above the fuel surface or for raising the level of
the fuel surface, and the level switch 57 corresponds to
means for detecting the level of the fuel surface.
When it is judged that the temperature of the
cooling water does not allow the fuel vapor eliminating
operation, or no fuel vapor eliminating operation needs
to be carried out, the electromagnetic valve 51 is
closed.
The fuel vapor eliminating operation according to
the fifth embodiment will be explained below by referring
to a flowchart in Fig. 12.
At step 510, it is judged if the level switch 57 is
on. When the level switch 57 is on, it is judged that no
fuel vapor eliminating operation needs to be carried out,
the routine proceeds to step 514 where the
electromagnetic valve 51 is closed, and the routine is
ended. On the other hand, when the level switch 57 is
off, it is judged that the fuel vapor eliminating
operation should be carried out, the routine proceeds to
step 516.
' ~ CA 02301030 2000-02-15
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At step 516, it is judged if the temperature T of
the cooling water is higher than the predetermined
temperature TO (T > TO). When T > T0, the temperature of
the cooling water does not allow the fuel vapor
eliminating operation, the routine proceeds to step 514
where the electromagnetic valve 51 is closed, and the
routine is ended. On the other hand, when T <_ T0, the
temperature of the cooling water allows the fuel vapor
eliminating operation, the routine proceeds to step 518
where the electromagnetic valve 51 is opened to introduce
the negative pressure into the fuel chamber 7, and the
routine is ended.
In the third embodiment, the pressure in the air
chamber 6 is kept at the pressure at which the relief
valve 37 is opened when the air pump is activated. After
the air pump 35 is stopped, the pressure in the air
chamber 6 is relieved through the hole 39 of the relief
valve 37 and is kept at the atmospheric pressure.
It takes a certain time until the pressure in the
air chamber 6 is sufficiently relieved by means of the
hole 39 since the hole 39 is small to prevent a sudden
decrease in pressure in the air chamber 6 and to not
prevent an increase in the pressure in the air chamber 6
by the air pump 35. Therefore, the fuel cannot flow into
the fuel chamber 7 through the fuel filling nozzle if the
pressure in the air chamber 6 is too high. According to
the sixth embodiment, the fuel can flow into the fuel
chamber 7 through the fuel filling nozzle even after the
pressure in the air chamber 6 is increased.
A fuel reserving device according to the sixth
embodiment of the invention will be explained below.
In the sixth embodiment, as shown in Fig. 13, a
second relief valve 59 is connected to the second
connection pipe 36. The second relief valve 59 is opened
to relieve the pressure in the air chamber 6 when the
pressure in the air chamber 6 is higher than a second
predetermined pressure. The second predetermined
' ~ CA 02301030 2000-02-15
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pressure is lower than the pressure of the fuel when the
fuel is supplied by the fuel filling nozzle. The amount
of the air relieved from the second relief valve 59 is
smaller than that pumped by the air pump 35, and is
larger than that flowing through the hole 39 of the
relief valve 37.
Components other than those described above are the
same as those of the fuel reserving device according to
the third embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
sixth embodiment will be explained below.
The fuel vapor elimination operation according to
the sixth embodiment is carried out in the same manner as
the third embodiment. Also, in the same manner as the
third embodiment, the air pump 35 is stopped when the
level switch 57 is on or the relief valve 37 is opened.
In the sixth embodiment, when the pressure in the
air chamber 6 is higher than the second predetermined
pressure after the air pump 35 is stopped, the second
relief valve 59 is opened. Therefore, the pressure in
the air chamber 6 becomes lower than the pressure of the
fuel when the fuel is supplied by the fuel filling nozzle
earlier than the third embodiment. Thus, the fuel can
flow into the fuel chamber 7 through the fuel filling
nozzle.
Further, according to the sixth embodiment, the
increasing rate of the pressure in the air chamber is
lower than that in the third embodiment when the pressure
is in the range between the opening pressure of the
second relief valve 59 and the opening pressure of the
relief valve 37.
A flowchart of the sixth embodiment is the same as
that of the third embodiment. Therefore, an explanation
thereof will not be given.
In the sixth embodiment, the pressure in the air
chamber 6 is increased by the air pump 35 with the
' ~ CA 02301030 2000-02-15
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pressure in the air chamber 6 being relieved by the
second relief valve 59 when the pressure in the air
chamber 6 is higher than the second predetermined
pressure. Therefore, the rate of the increase in the
pressure in the air chamber 6 in the sixth embodiment is
lower than that in the third embodiment which comprises
no second relief valve. Thus, in the sixth embodiment, a
time from when the opener switch 50 is on to when the
opening of the cap closure is allowed is longer than that
in the third embodiment. According to the seventh
embodiment, the fuel can flow into the fuel chamber 7
through the fuel filling nozzle even after the pressure
in the air chamber 6 is increased, and the rate of the
increase in the pressure in the air chamber becomes
larger than that in the sixth embodiment.
A fuel reserving device according to the seventh
embodiment of the invention will be explained below.
In the seventh embodiment, as shown in Fig. 14, an
electromagnetic valve 60, instead of the relief and the
second relief valves 37 and 59, is connected to the
second connection pipe 36. The electromagnetic valve 60
is connected to the output port 47 via a corresponding
drive circuit 49, and is controlled by the electronic
control unit 40. The electromagnetic valve 60 shuts off
the communication between the air chamber 6 and the
outside air.
A pressure sensor 61 for sensing the pressure in the
air chamber 6 is mounted on the upper portion 2 of the
tank 1. The sensor 61 is connected to the input port 46
via a corresponding AD converter 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the sixth embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
seventh embodiment will be explained below.
In the seventh embodiment, it is judged if the
' ' CA 02301030 2000-02-15
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pressure in the air chamber 6 is lower than a maximum
predetermined pressure. The maximum predetermined
pressure is lower than that at which the wall 5 may be
subject to a damage by the pressure in the air chamber 6.
When the pressure in the air chamber 6 is lower than the
maximum predetermined pressure, it is judged that the
condition of the engine and the fuel tank 1 allows the
fuel vapor eliminating operation.
Further, in seventh embodiment, it is judged if the
cap closure opener switch 50 and the level switch 57 are
on. When the cap closure opener switch 50 is on and the
level switch 57 is off, it is judged that the fuel vapor
eliminating operation should be carried out.
Further, in seventh embodiment, it is judged if the
pressure in the air chamber 6 is lower than a second
predetermined pressure. The second predetermined
pressure is lower than the pressure of the fuel when the
fuel is supplied by the fuel filling nozzle. When the
pressure in the air chamber 6 is lower than the second
predetermined pressure, it is judged that the pressure in
the air chamber 6 allows the cap closure to open.
When the condition of the engine and the fuel tank 1
allows the fuel vapor eliminating operation, and the fuel
vapor eliminating operation should be carried out, the
electromagnetic valve 60 is closed and the air pump 35 is
activated to increase the pressure in the air chamber 6.
Therefore, the fuel vapor above the fuel surface is
discharged from the fuel chamber 7 via the circulation
and the fuel vapor discharging pipes 23 and 24.
According to the seventh embodiment, the rate of the
increase in the pressure in the air chamber 6 is larger
than that in the sixth embodiment.
When no fuel vapor eliminating operation needs to be
carried out, the air pump 35 is stopped, the
electromagnetic valve 60 is opened to make the pressure
in the air chamber 6 lower than the second predetermined
pressure, and the opening of the cap closure is allowed.
' ~ CA 02301030 2000-02-15
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When the condition of the engine and the fuel tank 1
does not allow the fuel vapor eliminating operation, the
air pump 35 is stopped and the electromagnetic valve 60
is opened to make the pressure in the air chamber 6 lower
than the maximum predetermined pressure.
In the seventh embodiment, the air pump 35
corresponds to means for discharging gas from the space
formed above the fuel surface or for raising the level of
the fuel surface, and the level switch 57 corresponds to
means for detecting the level of the fuel surface.
The fuel vapor eliminating operation according to
the seventh embodiment will be explained below by
referring to a flowchart in Fig. 15.
At step 710, it is judged if the cap closure opener
switch 50 is on. When the switch 50 is on, the routine
proceeds to step 712. On the other hand, when the
switch 50 is off, i.e., when the supply of the fuel into
the fuel chamber 7 is completed, the routine proceeds to
step 722 where the electromagnetic valve 60 is closed to
keep the pressure in the air chamber 6 relatively high,
the routine proceeds to step 724 where the air pump 35 is
stopped, the routine proceeds to step 726 where a fuel
supply flag is reset, and the routine is ended. The fuel
supply flag is set when it is judged that the pressure in
the air chamber 6 does not allow the fuel vapor
eliminating operation, and is reset when the supply of
the fuel into the fuel chamber is completed.
At step 712, it is judged if the level switch 57 is
on. When the switch 57 is on, it is judged that no fuel
vapor eliminating operation needs to be carried out, the
routine proceeds to step 742 where the air pump 35 is
stopped, the routine proceeds to step 744 where the
electromagnetic valve 60 is opened to make the pressure
in the air chamber 6 lower than the second predetermined
pressure, the routine proceeds to step 746 where the
opening of the cap closure is allowed, and the routine is
ended.
" ' CA 02301030 2000-02-15
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On the other hand, at step 712, when the level
switch 57 is off, it is judged that the fuel vapor
eliminating operation should be carried out, and the
routine proceeds to step 714.
At step 714, it is judged if the pressure P in the
air chamber 6 is lower than the maximum predetermined
pressure Pmax (P < Pmax). When P < Pmax, the routine
proceeds to step 716. On the other hand, when P > Pmax,
it is judged that the pressure in the air chamber 6 does
not allow the fuel vapor eliminating operation since the
pressure in the air chamber 6 is already higher than the
maximum predetermined pressure, the routine proceeds to
step 728 where the fuel supply flag is set, the routine
proceeds to step 730 where the electromagnetic valve 60
is opened to decrease the pressure in the air chamber 6,
and the routine proceeds to step 732.
At step 716, it is judged if the fuel supply flag is
reset. When the flag is reset, it is judged that the
pressure in the air chamber 6 allows the fuel vapor
eliminating operation, the routine proceeds to step 718
where the electromagnetic valve 60 is closed, the routine
proceeds to step 720 where the air pump 35 is activated,
and the routine is ended.
On the other hand, when the fuel supply flag is set,
it is judged that the pressure in the air chamber 6 does
not allow the fuel vapor eliminating operation, and the
routine proceeds to step 732.
At step 732, it is judged if the pressure P in the
air chamber 6 is lower than the second predetermined
pressure P2 (P < P2). When P < P2, it is judged that the
pressure in the air chamber 6 allows the supply of the
fuel into the fuel chamber 7, the routine proceeds to
step 734 where the electromagnetic valve 60 is closed,
the routine proceeds to step 736 where the air pump 35 is
activated to keep the pressure in the air chamber 6
relative high during the supply of the fuel into the fuel
chamber 7, the routine proceeds to step 738 where the
' CA 02301030 2000-02-15
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opening of the cap closure is allowed, and the routine is
ended.
On the other hand, when P >_ P2, it is judged that
the pressure in the air chamber 6 does not allow the
supply of the fuel into the fuel chamber 7, the routine
proceeds to step 739 where the air pump 35 is stopped,
the routine proceeds to step 740 where the
electromagnetic valve 60 is opened, and the routine is
ended.
In the second embodiment, the fuel may move in the
fuel chamber when the rate of the increase in the
pressure in the air chamber is large. Therefore, the
first and second shut off valves may open so that the
fuel may enter into the circulation and fuel vapor
discharging pipes. According to the eighth embodiment,
the inclination of the increase in the pressure in the
air chamber is made smaller than that at which the fuel
may largely move in the fuel chamber.
A fuel reserving device according to the eighth
embodiment will be explained below.
In the eighth embodiment, as shown in Fig. 16, an
electromagnetic valve 60 instead of the relief valve 37
in the second embodiment is connected to the second
connection pipe 36. The valve 60 is connected to the
output port 47 via a corresponding drive circuit 49, and
is controlled by the electronic control unit 40. The
valve 60 shuts off the communication between the air
chamber 6 and the outside air.
A pressure sensor 61 for sensing the pressure in the
air chamber 6 is mounted on the upper portion 2 of the
tank 1. The sensor 61 is connected to the input port 46
via a corresponding AD converter 48.
A fuel level gauge 62 for detecting the amount of
the fuel in the fuel chamber 7 by detecting the position
of the wall 5 is mounted on the upper portion 2 of the
tank 1. The gauge 62 is connected to the input port 46
via a corresponding AD converter 48.
' ' CA 02301030 2000-02-15
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The fuel reserving device comprises a temperature
sensor 55 for generating a voltage corresponding to the
temperature of the cooling water for cooling the engine.
The temperature sensor 55 is connected to the input
port 46 via a corresponding AD convener 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the second embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
eight embodiment will be explained below.
In the eighth embodiment, it is judged if the
temperature of the cooling water is higher than a
predetermined temperature and the amount of the fuel in
the fuel chamber 7 is larger than a predetermined amount
of the fuel. The predetermined temperature is higher
than that of the cooling water when the cooling water
cools the engine in the constant driving condition, and
the predetermined amount of the fuel is larger than that
sufficient to raise the level of the fuel surface to the
highest level in the fuel chamber 7 when the separating
wall 5 is moved down.
When the temperature of the cooling water is higher
than a predetermined temperature and the amount of the
fuel in the fuel chamber 7 is larger than a predetermined
amount of the fuel, it is judged that the conditions of
the engine and the fuel tank 1 allow the fuel vapor
eliminating operation.
Further, in the eighth embodiment, it is judged if
the level switch 57 is off.
When the level switch 57 is off, it is judged that
the fuel vapor eliminating operation should be carried
out.
When the conditions of the engine and the fuel
tank 1 allow the fuel vapor eliminating operation and the
fuel vapor eliminating operation should be carried out,
the fuel vapor eliminating operation is carried out,
CA 02301030 2000-02-15
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i.e., the electromagnetic valve 60 is closed and the air
pump 35 is activated to increase the pressure in the air
chamber 6. Therefore, the central portion 5c of the
wall 5 is moved down to eliminate the fuel vapor from the
space above the fuel surface in the fuel chamber 7.
Further, in the eighth embodiment, while the fuel
vapor eliminating operation is carried out, it is judged
if the rate of the increase in the pressure in the air
chamber 6 is larger than that at which the fuel may
largely move in the fuel chamber 7 on the basis of the
pressure in the air chamber 6 detected by the pressure
sensor 61.
When the rate of the increase in the pressure in the
air chamber 6 is higher than that at which the fuel may
largely move in the fuel chamber 7, the air pump 35 is
stopped. On the other hand, when the rate of the
increase in the pressure in the air chamber 6 is lower
than that at which the fuel may largely move in the fuel
chamber 7, the air pump 35 is activated. Therefore, the
rate of the increase in the pressure in the air chamber 6
is kept lower than that at which the fuel may largely
move in the fuel chamber 7 so that movement of the fuel
in the fuel chamber 7 is prevented.
When the conditions of the engine and the fuel
tank does not allow the fuel vapor eliminating operation
or no fuel vapor eliminating operation needs to be
carried out, the fuel vapor eliminating operation is
stopped, i.e., the air pump 35 is stopped and the
electromagnetic valve 60 is opened.
In the eighth embodiment, the air pump 35
corresponds to means for discharging gas from the space
formed above the fuel surface or for raising the level of
the fuel surface, and the level switch 57 or the fuel
level gauge 62 corresponds to means for detecting the
level of the fuel surface.
The fuel vapor eliminating operation according the
eighth embodiment will be explained below by referring to
' ' CA 02301030 2000-02-15
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a flowchart in Fig. 17.
At step 810, it is judged if the temperature T of
the cooling water is higher than a predetermined
temperature TO (T > TO). The predetermined temperature
is that at which the purging of the fuel vapor discharged
into the intake passage 52 is allowed. When T > T0, it
is judged that the temperature of the cooling water
allows the purging of the fuel vapor discharged into the
intake passage 52, and the routine proceeds to step 812.
On the other hand, when T < T0, the temperature of
the cooling water does not allow the purging of the fuel
vapor discharged into the intake passage 52, the routine
proceeds to step 840 where the electromagnetic valve 60
is opened, the routine proceeds to step 842 where the
pump 35 is stopped, and the routine is ended.
At step 812, it is judged if the level switch 57 is
off. When the switch 57 is off, it is judged that the
fuel vapor eliminating operation should be carried out,
and the routine proceeds to step 814. On the other hand,
when the switch 57 is on, it is judged that no fuel vapor
eliminating operation needs to be carried out, the
routine proceeds to step 840 where the electromagnetic
valve 60 is opened, the routine proceeds to step 842
where the pump 35 is stopped, and the routine is ended.
At step 814, it is judged if the amount F of the
fuel in the fuel chamber 7 is larger than a predetermined
amount FO of the fuel (F > FO). The predetermined amount
of the fuel is larger than that sufficient to raise the
level of the fuel surface to the highest level in the
fuel chamber 7 when the separating wall 5 is moved down.
At step 814, when F > F0, the routine proceeds to
step 816.
On the other hand, at step 814, when F < F0, the
routine proceeds to step 840 where the electromagnetic
valve 60 is opened, the routine proceeds to step 842
where the pump 35 is stopped, and the routine is ended.
' CA 02301030 2000-02-15
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At step 816, it is judged if the electromagnetic
valve 60 is closed. When the valve 60 is closed, the
routine proceeds to step 818 where this time target
pressure Pn is calculated by adding a predetermined
pressure DP to last time target pressure, and the routine
proceeds to step 824.
On the other hand, at step 816, when the valve 60 is
opened, the routine proceeds to step 836 where the
valve 60 is closed, the routine proceeds to step 838
where the pressure in the air chamber 6 detected by the
pressure sensor 61 is input into the target pressure Pn
as an initial target pressure, and the routine is ended.
At step 820, it is judged if the target pressure Pn
is higher than a maximum pressure Pmax (Pn > Pmax). The
maximum pressure is lower than that at which the wall 5
may be subject to a damage by the pressure in the air
chamber 6. At step 820, when Pn > Pmax, the routine
proceeds to step 822 where the maximum pressure Pmax is
input into the target pressure to limit the pressure in
the air chamber 6 to the maximum pressure, and the
routine proceeds to step 824.
On the other hand, at step 820, when Pn < Pmax, the
routine proceeds to step 824.
At step 824, it is judged if the pressure P in the
air chamber 6 is lower than the maximum pressure Pmax
(P < Pmax). When P < Pmax, it is judged that the
pressure in the air chamber 6 allows the fuel vapor
eliminating operation, the routine proceeds to step 826.
On the other hand, when P > Pmax, it is judged that the
pressure in the air chamber 6 does not allow the fuel
vapor eliminating operation, the routine proceeds to
step 832 where the electromagnetic valve 60 is opened,
the routine proceeds to step 834 where the air pump 35 is
stopped, and the routine is ended.
At step 826, it is judged if the pressure P in the
air chamber 6 is lower than the target pressure Pn (P <
Pn). When P < Pn, it is judged that the rate of the
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increase in the pressure in the air chamber 6 is lower
than that at which the fuel may largely move in the fuel
chamber, the routine proceeds to step 828 where the
electromagnetic valve 60 is closed, the routine proceeds
to step 830 where the air pump 35 is activated, and the
routine in ended.
On the other hand, at step 826, when P >_ Pn, it is
judged that the rate of the increase in the pressure in
the air chamber 6 is higher than that at which the fuel
may largely move in the fuel chamber 7, the routine
proceeds to step 834 where the air pump 35 is stopped,
and the routine is ended.
In the eighth embodiment, the fuel vapor discharged
from the fuel chamber is introduced into the intake
passage. Therefore, the air-fuel ratio of the air-fuel
mixture is decreased by the fuel vapor introduced, i.e.,
the air-fuel ratio is not kept at a desired predetermined
air-fuel ratio. According to the ninth embodiment, the
air-fuel ratio is kept at a desired predetermined air-
fuel ratio when the fuel vapor discharged is introduced
into the intake passage.
A fuel reserving device according to the ninth
embodiment of the invention will be explained below.
In the ninth embodiment, as shown in Fig. 18, the
fuel reserving device comprises an air-fuel ratio
sensor 63 for generating a voltage corresponding to an
air-fuel ratio in the intake passage. The air-fuel ratio
sensor 63 comprises an oxygen sensor or a linear sensor
which generates a voltage corresponding to a
concentration of the oxygen in the exhaust gas. The
sensor 63 is connected to the input port 46 via a
corresponding AD converter 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the eighth embodiment. Therefore, an explanation thereof
will not be given.
A fuel vapor eliminating operation according to the
' CA 02301030 2000-02-15
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ninth embodiment will be explained below.
In the ninth embodiment, it is judged if the
temperature of the cooling water is higher than a
predetermined temperature, if the amount of the fuel in
the fuel chamber 7 is larger than a predetermined amount
of the fuel, and if the pressure in the air chamber 6 is
lower than a predetermined pressure. The predetermined
temperature is higher than that of the cooling water when
the cooling water cools the engine in a constant driving
condition, the predetermined amount of the fuel is larger
than that sufficient to raise the level of the fuel
surface to the highest level in the fuel chamber 7 when
the wall 5 is moved down, and the predetermined pressure
is lower than that at which the wall may be subject to a
damage by the pressure in the air chamber.
When the temperature of the cooling water is higher
than a predetermined temperature, it the amount of the
fuel in the fuel chamber 7 is larger than a predetermined
amount of the fuel, and it the pressure in the air
chamber 6 is lower than a predetermined pressure, it is
judged that the conditions of the engine and the fuel
tank 1 allow the purging of the fuel vapor.
Further, in the ninth embodiment, it is judged if
the level switch 57 is off. When the switch 57 is off,
it is judged that the fuel vapor eliminating operation
should be carried out.
Further, in the ninth embodiment, it is judged if
the air-fuel ratio detected by the air-fuel ratio
sensor 63 is larger than a predetermined ratio. The
predetermined ratio is at a desired air-fuel ratio. When
the air-fuel ratio detected is larger than the
predetermined ratio, it is judged that the air-fuel ratio
allows the fuel vapor eliminating operation to continue.
When the conditions of the engine and the fuel
tank 1 allow the purging of the fuel vapor, the fuel
vapor eliminating operation should be carried out, and
the air-fuel ratio allows to continue to carry out the
CA 02301030 2000-02-15
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fuel vapor eliminating operation, the fuel vapor
eliminating operation is carried out, i.e., the
electromagnetic valve 60 is closed, and the air pump 35
is activated to increase the pressure in the air
chamber 6. Therefore, the central portion 5c of the
wall 5 is moved down to eliminate the fuel vapor from the
space above the fuel surface in the fuel chamber 7.
When the air-fuel ratio does not allow the fuel
vapor eliminating operation to continue even if the
conditions of the engine and the fuel tank 1 allow the
purging of the fuel vapor and the fuel vapor eliminating
operation should be carried out, the fuel vapor
eliminating operation is stopped, i.e., the air pump 35
is stopped.
Therefore, according to the ninth embodiment, the
amount of the fuel vapor introduced into the intake
passage is controlled so that the air-fuel ratio is kept
at the desired predetermined ratio.
Of course, when the conditions of the engine and the
fuel tank 1 does not allow the purging of the fuel vapor
or no fuel vapor eliminating operation needs to be
carried out, the fuel vapor eliminating operation is
stopped, i.e., the air pump 35 is stopped.
In the ninth embodiment, the purging of the fuel
vapor into the intake passage corresponds to means for
discharging gas from the space formed above the fuel
surface or for raising the level of the fuel surface, and
the level switch 57 or the fuel level gauge 62
corresponds to means for detecting the level of the fuel
surface.
The fuel vapor eliminating operation according to
the ninth embodiment will be explained below by referring
to a flowchart in Fig. 19. In the flowchart, steps 910,
912 and 914 correspond to steps 810, 812 and 814 in
Fig. 17, respectively. Therefore, an explanation thereof
will not be given.
At step 914, when F > F0, the routine proceeds to
CA 02301030 2000-02-15
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step 916. On the other hand, when F < F0, the routine
proceeds to step 924 where the electromagnetic valve 60
is opened, the routine proceeds to step 926 where the air
pump 35 is stopped, and the routine is ended.
At step 916, it is judged if the pressure P in the
air chamber 6 is lower than the maximum pressure Pmax
(P < Pmax). When P < Pmax, it is judged that the
pressure in the air chamber 6 allows the fuel vapor
eliminating operation and the routine proceeds to
step 918. On the other hand, when P > Pmax, it is judged
that the pressure in the air chamber 6 does not allow the
fuel vapor eliminating operation, the routine proceeds to
step 924 where the electromagnetic valve 60 is opened,
the routine proceeds to step 926 where the air pump 35 is
stopped, and the routine is ended.
At step 918, it is judged if the air-fuel ratio AF
is larger than the desired predetermined ratio AFO (AF >
AFO). When AF > AFO, it is judged that the air-fuel
ratio allows the fuel vapor eliminating operation to
continue, the routine proceeds to step 920 where the
electromagnetic valve 60 is closed, the air pump 35 is
activated, and the routine is ended.
On the other hand, when AF < AFO, it is judged that
the air-fuel ratio does not allow the fuel vapor
eliminating operation to continue, the routine proceeds
to step 926 where the air pump 35 is stopped, and the
routine is ended.
In the third and seventh embodiments, the supply of
the fuel into the fuel chamber is carried out when the
pressure in the air chamber is kept increased.
Therefore, the increased pressure in the air chamber may
force the fuel in the fuel chamber to flow back into the
fuel feeding pipe when the supply of the fuel into the
fuel chamber is stopped. According to the tenth
embodiment, the flow of the fuel in the fuel chamber back
into the fuel feeding pipe is prevented.
A fuel reserving device according to the tenth
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embodiment of the invention will be explained below.
In the tenth embodiment, as shown in Fig. 20, a fuel
level gauge 62 for detecting the amount of the fuel in
the fuel chamber by detecting the position of the wall 5
S is mounted on the upper portion 2 of the fuel tank 1.
The gauge 62 is of a pendulum type, one end of which is
positioned on the central portion 5c of the wall 5, and a
voltage is generated according to the angle of the
pendulum (i.e., the position of the fuel surface). The
generated voltage is input into the input port 46 via a
corresponding AD converter 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the seventh embodiment. Therefore, an explanation
thereof will not be given.
A fuel vapor eliminating operation according to the
tenth embodiment will be explained below.
The fuel vapor eliminating operation is carried out
in the same manner as that in the seventh embodiment
until the opening of the cap closure is allowed.
Therefore, an explanation thereof will not be given.
In the tenth embodiment, after the cap closure is
opened, the supply of the fuel into the fuel chamber 7 is
carried out until the fuel chamber 7 is full with fuel.
Further, in the tenth embodiment, the
electromagnetic valve 60 is opened to decrease the
pressure in the air chamber 6 when a predetermined time
has elapsed. The predetermined time is that from
detecting the fuel chamber 7 to be full with the fuel to
the stopping of the supply of the fuel into the fuel
chamber 7.
Therefore, according to the tenth embodiment, the
pressure in the air chamber 6 is decreased when the
supply of the fuel into the fuel chamber 7 is stopped.
Thus, the flow of the fuel back into the fuel feeding
pipe is prevented.
In the ninth embodiment, the air pump 35 or the fuel
CA 02301030 2000-02-15
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level gauge 62 corresponds to means for discharging gas
from the space formed above the fuel surface or for
raising the level of the fuel surface, and the level
switch 57 corresponds to means for detecting the level of
the fuel surface.
The fuel vapor eliminating operation according to
the tenth embodiment will be explained below by referring
to a flowchart in Figs. 21 and 22.
At step 1010 in Fig. 21, it is judged if the cap
closure opener switch 50 is on. When the switch 50 is
on, the routine proceeds to step 1012. On the other
hand, when the switch 50 is off, it is judged that no
supply of the fuel into the fuel chamber 7 is to be
carried out, the routine proceeds to step 1050 in Fig. 22
where the end flag is set, the routine proceeds to
step 1052 where the air pump 35 is stopped, the routine
proceeds to step 1054 where the electromagnetic valve 60
is opened, and the routine proceeds to step 1056. The
end flag is set when the cap closure is closed, and is
reset when first fuel supply, second fuel supply and
counter flags as described below are reset.
At step 1012 in Fig. 21, it is judged if the level
switch 57 is on. When the switch 57 is on, it is judged
that no fuel vapor eliminating operation needs to be
carried out, the routine proceeds to step 1024 where the
second fuel supply flag is set, the routine proceeds to
step 1026 where the air pump 35 is stopped, the routine
proceeds to step 1028 where the electromagnetic valve 60
is opened, the routine proceeds to step 1030 where the
opening of the cap closure is allowed to carry out the
supply of the fuel into the fuel chamber 7, and the
routine proceeds to step 1032. The second fuel supply
flag is set when the level switch 57 is off and is reset
when the cap closure is closed.
On the other hand, at step 1012, when the switch 57
is off, it is judged that the fuel vapor eliminating
operation should be carried out, and the routine proceeds
' ' CA 02301030 2000-02-15
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to step 1014.
At step 1014, it is judged if the pressure P in the
air chamber 6 is lower than a maximum pressure Pmax (P <
Pmax). The maximum pressure is lower than that at which
the wall 5 may be subject to a damage by the pressure in
the air chamber 6. When P < Pmax, it is judged if the
pressure in the air chamber 6 allows the fuel vapor
eliminating operation, the routine proceeds to step 1016.
On the other hand, when P >_ Pmax, it is judged if the
pressure in the air chamber 6 does not allow the fuel
vapor eliminating operation, the routine proceeds to
step 1022 where the first fuel supply flag is set, the
routine proceeds to step 1026 where the air pump 35 is
stopped, the routine proceeds to step 1028 where the
electromagnetic valve 60 is opened, the routine proceeds
to step 1030 where the opening of the cap closure is
allowed, and the routine proceeds to step 1032. The
first fuel supply flag is set when the pressure in the
air chamber 6 is higher than the maximum pressure and is
reset when the cap closure is closed.
At step 1016, it is judged if the first fuel supply
flag is reset. When the flag is reset, it is judged that
the pressure in the air chamber 6 has not become the
maximum pressure yet, the fuel vapor eliminating
operation is carried out, i.e., the routine proceeds to
step 1018 where the electromagnetic valve 60 is closed,
the routine proceeds to step 1020 where the air pump 35
is activated to increase the pressure in the air
chamber 6, and the routine is ended.
On the other hand, at step 1016, when the flag is
set, it is judged that the air pump 35 should not be
activated even if the pressure in the air chamber 6 is
lower than the maximum pressure, the routine proceeds to
step 1026 where the air pump 35 is stopped, the routine
proceeds to step 1028 where the electromagnetic valve 60
is opened, the routine proceeds to step 1030 where the
opening of the cap closure is allowed, and the routine
' ' CA 02301030 2000-02-15
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proceeds to step 1032.
At step 1032, it is judged if the counter flag is
reset. The counter flag is set when the fuel chamber 7
is full with fuel and is reset when the cap closure is
closed. When the counter flag is reset, it is judged
that the fuel chamber 7 is not full with fuel yet, and
the routine proceeds to step 1034. On the other hand,
when the counter flag is set, it is judged that the fuel
chamber 7 is full with fuel, and the routine proceeds to
step 1042.
At step 1034, it is judged if the fuel chamber 7 is
full with fuel. When the fuel chamber 7 is full with the
fuel, the routine proceeds to step 1036 where the count
is reset, the routine proceeds to step 1038 where the
counter flag is set, and the routine is ended. On the
other hand, when the fuel chamber 7 is not full with the
fuel, the routine proceeds to step 1040 in Fig. 22.
At step 1040, it is judged if the second fuel supply
flag is set. When the second fuel supply flag is set, it
is judged that no fuel vapor eliminating operation needs
to be carried out, and the routine is ended. On the
other hand, when the second fuel supply flag is reset, it
is judged that the fuel vapor eliminating operation
should be carried out, and the routine proceeds to
step 1044.
At step 1042, it is judged if the count t is smaller
than a predetermined count t0 (t < t0). The
predetermined count is that between the detection of the
fuel chamber 7 being full with fuel and the stopping of
the supply of the fuel into the fuel chamber 7. When t <
t0, the routine proceeds to step 1043 where the count is
counted up, and the routine proceeds to step 1044.
On the other hand, at step 1042, when t > t0, it is
judged that the supply of the fuel into the fuel
chamber 7 is stopped, the routine proceeds to step 1050
where the end flag is set, the routine proceeds to
step 1052 where the air pump 35 is stopped, the routine
' , CA 02301030 2000-02-15
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proceeds to step 1054 where the electromagnetic valve 60
is opened, and the routine proceeds to step 1056.
At step 1044, it is judged if the pressure P in the
air chamber 6 is lower than a second predetermined
pressure P2 (P < P2). The second predetermined pressure
is lower than the pressure of the fuel when the fuel is
supplied by the fuel filling nozzle. When P < P2, it is
judged that the pressure in the air chamber 6 allows the
supply of the fuel into the fuel chamber 7, the routine
proceeds to step 1046 where the electromagnetic valve 60
is closed, the routine proceeds to step 1048 where the
air pump 35 is activated, and the routine is ended.
On the other hand, at step 1044, when P > P2, it is
judged that the pressure in the air chamber 6 does not
allow the supply of the fuel into the fuel chamber 7, the
routine proceeds to step 1052 where the air pump 35 is
stopped, the routine proceeds to step 1054 where the
electromagnetic valve 60 is opened, and the routine
proceeds to step 1056.
At step 1056, it is judged if the end flag is set.
When the end flag is set, it is judged that the supply of
the fuel into the fuel chamber 7 is completed, the
routine proceeds to step 1058 where the first fuel supply
flag is reset, the routine proceeds to step 1060 where
the second fuel supply flag is reset, the routine
proceeds to step 1062 where the counter flag is reset,
the routine proceeds to step 1064 where the end flag is
reset, and the routine is ended.
On the other hand, at step 1056, when the end flag
is reset, it is judged that the supply of the fuel into
the fuel chamber 7 is not completed, and the routine is
ended.
In the first to tenth embodiments, the fuel pump 19
is positioned in the fuel tank. The shape of the fuel
pump 19 is not simple so that the wall 5 cannot come into
contact with the fuel surface around the fuel pump 19.
Therefore, a space may be formed between the separating
' ' CA 02301030 2000-02-15
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wall 5 and the fuel surface around the fuel pump 19.
According to the eleventh embodiment, no space may be
formed between the wall 5 and the fuel surface around the
fuel pump 19.
A fuel reserving device according to the eleventh
embodiment of the invention will be explained below.
In the eleventh embodiment, as shown in Fig. 23, the
fuel pump 19 is positioned outside of the fuel tank 1.
The fuel pump 19 is connected to the fuel filter 21 via a
fuel pump pipe 19a. The pipe 19a extends through the
lower portion 3 under the lower opening of the fuel
feeding pipe 13. The fuel filter 21 is positioned in the
fuel chamber 7.
The pressure regulator 20 is positioned downstream
of the fuel pump 19. A fuel return passage 64 extends
from the pressure regulator 20 to within the fuel
chamber 7. The passage 64 serves to return the excess
fuel into the fuel chamber 7.
In the eleventh embodiment, the fuel reserving
device does not comprise a pump chamber so that the fuel
vapor discharging pipe is eliminated. The level
switch 57 is positioned at the lower portion 3 adjacent
to the anchor portion 8.
Components other than those described above are the
same as those of the fuel reserving device according to
the fourth embodiment. Therefore, an explanation thereof
will not be given.
Therefore, according to the eleventh embodiment, the
shape inside the fuel tank 1 becomes simpler so that no
space is formed between the separating wall 5 and the
fuel surface.
In the eleventh embodiment, the purging of the fuel
vapor into the intake passage corresponds to means for
discharging gas from the space formed above the fuel
surface or for raising the level of the fuel surface, and
the level switch 57 corresponds to means for detecting
the level of the fuel surface.
' ~ CA 02301030 2000-02-15
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Of course, the eleventh embodiment can apply to any
embodiment described above.
In the first embodiment, fuel vapor is generated
from the fuel in the fuel feeding pipe 13 after the
supply of the fuel into the fuel chamber 7 is completed.
According to the twelfth embodiment, the generation of
the fuel vapor from the fuel in the fuel feeding pipe 13
is prevented.
In the twelfth embodiment, as shown in Fig. 24, the
lower opening of the fuel feeding pipe 13 is mounted on
the anchor portion 8. The fuel feed pipe 13 is
positioned above the lower opening thereof.
Preferably, the lower opening of the fuel feeding
pipe 13 is positioned above the highest position in the
fuel chamber 7. In this case, the fuel in the fuel
feeding pipe 13 is completely eliminated therefrom.
Components other than those described above are the
same as those of the fuel reserving device according to
the first embodiment. Therefore, an explanation thereof
will not be given.
Therefore, according to the twelfth embodiment, the
fuel in the fuel feeding pipe 13 flows into the fuel
chamber 7 by its weight as the fuel in the fuel chamber 7
is decreased. Thus, the generation of the fuel vapor
from the fuel in the fuel feeding pipe 13 is prevented.
In the twelfth embodiment, the supply of the fuel
into the fuel chamber corresponds to means for
discharging gas from the space formed above the fuel
surface or for raising the level of the fuel surface.
Of course, the twelfth embodiment can apply to any
embodiment described above.
In the twelfth embodiment, the fuel in the fuel
feeding pipe 13 flows into the fuel chamber 7 as the fuel
in the fuel chamber 7 is decreased. Therefore, it takes
a certain time until the fuel in the fuel feeding pipe 13
completely flows into the fuel chamber 7. Thus, before
all the fuel in the fuel feeding pipe 13 flows into the
' ' , CA 02301030 2000-02-15
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fuel chamber 7, fuel vapor may be generated from the fuel
in the fuel feeding pipe 13. According to the thirteenth
embodiment, the generation of the fuel vapor in the fuel
feeding pipe 13 is further prevented.
In the thirteenth embodiment, as shown in Fig. 25,
the air chamber 6 is connected to the air pump 35 via a
first connection pipe 34 instead of the atmosphere
pipe 33. The first connection pipe 34 is connected to an
electromagnetic valve 60 via the second connection
pipe 36. The valve 60 is connected to the output port 47
via a corresponding drive circuit 49. The valve 60 is
controlled by the electronic control unit 40.
A pressure sensor 61 for sensing the pressure in the
air chamber 6 is mounted on the upper portion 2 of the
tank 1. The sensor 61 is connected to the input port 46
via a corresponding AD converter 48.
A fuel level gauge 62 for detecting the amount of
the fuel in the fuel chamber 7 by detecting the position
of the separating wall 5 is mounted on the upper
portion 2 of the tank 1. The gauge 62 is connected to
the input port 46 via a corresponding AD converter 48.
Components other than those described above are the
same as those of the fuel reserving device according to
the twelfth embodiment. Therefore, an explanation
thereof will not be given.
A fuel vapor eliminating operation according to the
thirteenth embodiment will be explained below.
The fuel vapor eliminating operation is carried out
in the same manner as that in the tenth embodiment until
the opening of the cap closure is allowed. Therefore, an
explanation thereof will not be given.
In the thirteenth embodiment, after the cap closure
is opened, the supply of the fuel into the fuel chamber 7
is carried out until the fuel chamber 7 is full of fuel.
Further, in the thirteenth embodiment, the
electromagnetic valve 60 is opened to decrease the
pressure in the air chamber 6 when a predetermined time
CA 02301030 2000-02-15
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has elapsed. The predetermined time is that from the
detection of the fuel chamber 7 being full with fuel to
just after the stopping of the supply of the fuel into
the fuel chamber 7.
Therefore, according to the thirteenth embodiment,
the pressure in the air chamber 6 is decreased when the
supply of the fuel into the fuel chamber 7 is stopped.
Thus, the fuel in the fuel feeding pipe 13 flows into the
fuel chamber 7 so that the generation of the fuel vapor
in the fuel feeding pipe 13 is further prevented.
In the thirteenth embodiment, the air pump 35
corresponds to means for discharging gas from the space
formed above the fuel surface or for raising the level of
the fuel surface, and the level switch 57 or the fuel
level gauge 62 corresponds to means for detecting the
level of the fuel surface.
The fuel vapor eliminating operation according to
the thirteenth embodiment will be explained below by
referring to a flowchart in Figs. 26 and 27. In the
flowchart, steps 1310 to 1360 except for step 1342
correspond to steps 1010 to 1060 in Figs. 21 and 22,
respectively. Therefore, an explanation thereof will not
be given.
At step 1342, it is judged if the count t is smaller
than a predetermined count tl (t < tl). The
predetermined count is that from the detection of the
fuel chamber 7 being full with fuel to just after the
stopping of the supply of the fuel into the fuel
chamber 7. When t < tl, the routine proceeds to
step 1343 where the count is counted up, and the routine
proceeds to step 1344.
On the other hand, at step 1342, when t >_ tl, it is
judged that the supply of the fuel into the fuel
chamber 7 is stopped, the routine proceeds to step 1350
where the end flag is set, the routine proceeds to
step 1352 where the air pump 35 is stopped, the routine
proceeds to step 1354 where the electromagnetic valve 60
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is opened, and the routine proceeds to step 1356.
In the above embodiments, the air pump is activated,
or the electromagnetic valve 60 is opened, on the basis
of the opening of the relief valve, or the pressure in
the air chamber 6, or the level switch 57. However, the
air pump may be activated, or the electromagnetic
valve 60 may be opened, on the basis of the position of
the wall 5.
A fuel reserving device according to the fourteenth
embodiment of the invention will be explained below.
In the fourteenth embodiment, as shown in Fig. 28,
the fuel reserving device comprises a fuel tank body 140.
The body 140 comprises upper and lower portions 91 and 92
which are generally cup-shaped. These portions 91 and 92
are connected to each other at flange portions 91a, 92a
thereof.
A fuel reservoir 94 which forms a fuel chamber 93
therein for reserving and storing fuel is housed within
the body 140. The reservoir 94 comprises an upper
rectangular wall 95 which is deformable and has a
rigidity, a lower rectangular wall 96 which is deformable
and has a rigidity, and a band-shaped wall or connecting
wall 97 which is deformable, has a rigidity and connects
the peripheral edge 95a of the upper wall 95 to the
peripheral edge 96a of the lower wall 96 as shown in
Fig. 29.
As shown in Fig. 30, the upper and lower walls 95
and 96 are deformed in such a manner that the walls 95
and 96 are swelled or expanded outwardly when the amount
of the fuel in the reservoir 94 is increased. As a
result of the deforming of the walls 95 and 96, the
connecting wall 97 is bent inwardly. Therefore, the
volume of the reservoir 94 is increased.
On the other hand, when the amount of the fuel in
the reservoir 94 is decreased, the upper and lower
walls 95 and 96 which are bent outwardly and the
connecting wall 97 which is bent inwardly return to their
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original shapes as shown in Fig. 29. Therefore, the
volume of the reservoir 94 is decreased.
Further, as shown in Fig. 31, when the amount of the
fuel in the reservoir 94 is decreased, the upper and
lower walls 95 and 96 are deformed in such a manner that
the walls 95 and 96 are swelled inwardly. As a result of
the deforming of the walls 95 and 96, the connecting
wall 97 is bent inwardly. Therefore, the volume of the
reservoir 94 is decreased.
The rigidity of the connecting wall 97 is larger
than those of the upper and lower walls 95 and 96.
A fuel passage opening 98 is formed at the central
portion of the lower wall 96 of the fuel reservoir 94. A
connecting pipe opining 99 is formed at the central
portion of the lower portion 92 of the fuel tank
body 140. The reservoir 94 is positioned in the fuel
tank body 140 in such a manner that the fuel passage
opening 98 is aligned with the connecting pipe
opening 99.
An air chamber 110 is formed outside of the fuel
reservoir 94 and inside of the fuel tank body 140. A
fuel level sensor 111 for detecting the position or the
amount of the movement of the upper wall 95 of the
reservoir 94 to calculate the amount of the fuel in the
reservoir 94 is mounted on the inner face of the upper
portion 91 of the fuel tank body 140.
Further, an air passage opening 112 is formed in the
upper portion 91 of the fuel tank body 140. The volume
of the air chamber 110 is increased or decreased when the
volume of the fuel reservoir 94 is decreased or
increased. At this time, air can flow in or out of the
air chamber 110 via the air passage opening 112.
Therefore, the reservoir 94 can be easily deformed.
A filter 113 for preventing objects except for the
air from flowing into the air chamber 110 is inserted
into the air passage opening 112.
One end of a fuel pipe 114 for introducing the fuel
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into the fuel reservoir 94 and withdrawing the fuel from
the reservoir 94 is inserted into the fuel passage
opening 98 of the reservoir 94 and the connecting pipe
opening 99 of the lower portion 92 of the fuel tank
body 140, and is connected thereto.
The other end of the fuel pipe 114 is connected to a
lower end of a fuel feeding pipe 115 for feeding fuel to
the reservoir 94 and one end of a fuel introducing
pipe 117 for introducing the fuel from the reservoir 94
to a fuel pump device 116. The other end of the fuel
introducing pipe 117 is connected to the fuel pump
device 116.
The fuel pump device 116 pumps the fuel in the
reservoir 94, and feeds the fuel to injectors (not shown)
of the engine. One end of a pump fuel vapor pipe 118 for
discharging fuel vapor from the fuel pump device 116 is
connected to the fuel pump device 116. The other end of
the pump fuel vapor pipe 118 is connected to the fuel
feeding pipe 115 adjacent to an upper opening of the fuel
feeding pipe 115. Further, one end of a fuel conveying
pipe 120 for conveying the fuel from the fuel pump
device 116 to the injectors is connected to the fuel pump
device 116.
One of a reservoir fuel vapor pipe 150 for
discharging fuel vapor from the reservoir 94 is connected
to the upper wall 95 of the reservoir 94. The other end
of the reservoir fuel vapor pipe 150 is connected to the
fuel pump device 116. Further, a fuel vapor pipe shut
off valve or reservoir sealing valve 149 is arranged in
the one end of the reservoir fuel vapor pipe 150.
The fuel vapor pipe shut off valve 149 comprises a
float 151, the density of which is smaller than that of
the fuel.
The opening of the reservoir fuel vapor pipe 150
which is open to the interior of the reservoir 94
corresponds to a discharge passage which is open to the
space above the fuel surface, and the fuel vapor shut off
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valve 149 corresponds to a shut off valve for shutting
off the above-mentioned discharge passage.
One end of a fuel vapor pipe 121 for discharging
fuel vapor adjacent to the upper opening 119 therefrom is
connected to the fuel feeding pipe 115 at the upper
opening side of the above other end of the pump fuel
vapor pipe 118. The other end of the fuel vapor pipe 121
is connected to a charcoal canister 122 for adsorbing
fuel vapor thereon and temporarily storing the fuel vapor
therein.
An activated carbon 123 for adsorbing fuel vapor
thereon is positioned in the canister 122. The interior
of the canister 122 is divided by the activated
carbon 123. Therefore, a fuel vapor chamber 124 is
formed at one side of the carbon 123, and an air
chamber 125 is formed at other side of the carbon 123.
The above-mentioned other end of the fuel vapor
pipe 121 is connected to the fuel vapor chamber 124 in
the canister 122. Further, one end of a canister fuel
vapor pipe 126 for discharging fuel vapor adsorbed on the
activated carbon 123 from the canister 122 to an intake
passage 127 of the engine is connected to the fuel vapor
chamber 124. The other end of the canister fuel vapor
pipe 126 is connected to a surge tank 128 formed in the
intake passage 127.
A fuel vapor amount control valve 129 for opening or
closing the canister fuel vapor pipe 126 is arranged in
the canister fuel vapor pipe 126. The fuel vapor amount
control valve 129 is controlled by a control unit (not
shown). One end of an air pipe 130 for introducing air
to the air chamber 125 of the canister 122 is connected
to the air chamber 125. The other end of the air
pipe 130 is connected to an air cleaner 131 arranged in
the intake passage 127. A shut off valve 132 for opening
or closing the air pipe 130 is arranged in the air
pipe 130. The shut off valve 132 is controlled by a
control unit (not shown). A throttle valve 133 for
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controlling the amount of the air which is fed to an
engine body 180 of the engine is arranged in the intake
passage 127.
In the fourteenth embodiment, the fuel vapor amount
control valve 129 is opened when the fuel vapor in the
charcoal canister 122 should be introduced into the
intake passage 127. The fuel vapor amount control
valve 129 is normally closed. Therefore, when the fuel
vapor amount control valve 129 is opened, the negative
pressure in the surge tank 128 is introduced into the
canister 122 via the canister fuel vapor pipe 126, and
the air in the air cleaner 131 is introduced into the
canister 122 via the air pipe 130. Thus, the fuel vapor
in the canister 122 is introduced to the intake
passage 127.
Further, the fuel vapor amount control valve 129 is
controlled on the basis of the driving conditions of the
engine to control the amount of the fuel vapor to be
introduced to the intake passage 127 in such a manner
that a desired predetermined air-fuel ratio can be
obtained. Therefore, the fuel vapor amount control
valve 129 corresponds to means for controlling the amount
of the fuel vapor to be discharged into the intake
passage 127, and the shut off valve 132 corresponds to
means for controlling the introduction of the air into
the canister 122.
In the fourteenth embodiment, when a leakage in the
fuel system which is in communication with the charcoal
canister 122 should be detected, a negative pressure is
introduced into the fuel system which extends from the
canister 122 to the fuel tank body 140, and thereafter,
the fuel vapor amount control and shut off valves 129 and
132 are closed to seal the above-mentioned fuel system.
Then, when the increase in the pressure in the fuel
system toward the atmospheric pressure is detected by a
pressure sensor (not shown), it is judged that the fuel
system has a leakage portion. Therefore, the fuel vapor
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amount control and shut off valves 129 and 132
corresponds to means for detecting the leakage of the
fuel.
The fuel pump device according to the fourteenth
embodiment of the invention will be explained below in
detail.
In the fourteenth embodiment, as shown in Fig. 32,
the fuel pump device 116 comprises a pump chamber 153
defined by a housing 152. The pump chamber 153 is
divided into a pump chamber portion 155 and sub-tank
chamber 156 by a pump chamber separating wall 154.
The pump chamber separating wall 154 comprises a
vertical wall 154a which extends generally vertically and
downwardly from an inner face of an upper wall of the
housing 152, and a horizontal wall 154b which extends
horizontally to an inner face of a side wall of the
housing 152 above an inner face of a lower wall of the
housing 152.
The above-mentioned one end of the pump fuel vapor
pipe 118 for discharging fuel vapor from the pump chamber
portion 155 is connected to the upper wall of the
housing 152. The opening of the one end of the pump fuel
vapor pipe 118 is open adjacent to the upper wall of the
housing 152 in the pump chamber portion 155.
A fuel pump 157 for feeding fuel from the sub-tank
chamber 156 to the injectors via the fuel conveying
pipe 120 is positioned in the sub-tank chamber 156. A
first fuel filter 158 for filtering the fuel pumped into
the fuel pump 157 is connected to a lower wall of the
fuel pump 157. Further, a pressure regulator 159 for
regulating the pressure of the fuel pumped by the fuel
pump 157 is arranged in the fuel conveying pipe 120 in
the sub-tank chamber 156.
An upper end of a fuel returning pipe 161 for
returning a portion of the fuel pumped by the fuel
pump 157 to the sub-tank chamber 156 is connected to the
pressure regulator 159. Further, a second fuel
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filter 160 for filtering the fuel pumped from the fuel
pump 157 is arranged in the fuel conveying pipe 120
between the pressure regulator 159 and the fuel pump 157.
A lower tip portion 162 of the fuel returning
pipe 161 is generally horizontally directed, and is
tapered in such a manner that the diameter of the tip
portion 162 becomes smaller as the tip portion 162
proceeds to an opening thereof. The lower tip
portion 162 is housed in a negative pressure generating
housing 163 for generating a negative pressure by
returning or recirculating a portion of the fuel pumped
by the fuel pump 157 to the sub-tank chamber 156. The
negative pressure generating housing 163 comprises a
trumpet-shaped fuel discharging pipe 164 which is tapered
in such a manner that the diameter of the fuel
discharging pipe 164 becomes larger as the fuel
discharging pipe 164 proceeds to an opening thereof.
The fuel discharging pipe 164 is aligned with the
lower tip portion 162. Further, a lower end of the
reservoir fuel vapor pipe 150 is housed in the negative
pressure generating housing 163.
The reservoir fuel vapor pipe 150 in the sub-tank
chamber 156 comprises a sub-tank chamber negative
pressure introducing pipe 165 for introducing the
negative pressure into the sub-tank chamber 156. The
introducing pipe 165 is open to the interior of the sub-
tank chamber 156 at the upper area in the sub-tank
chamber 156. Further, the diameter of the introducing
pipe 165 is smaller than that of the reservoir fuel vapor
pipe 150.
A vertical annular wall 167, which extends
vertically and downwardly from the horizontal wall 154b
of the pump chamber separating wall 154, is arranged on
the horizontal wall 154b. The vertical annular wall 167
forms a fuel intake passage 166 for introducing the fuel
into the sub-tank chamber 156. The location of an upper
opening of the fuel intake passage 166 is lower than that
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of a bottom wall face of the fuel introducing pipe 117.
A horizontal annular wall 168 which extends
horizontally from the vertical annular wall 167 toward
the fuel discharging pipe 164 is arranged on a lower end
of the vertical annular wall 167. The horizontal annular
wall 168 forms a fuel passing passage 169 for passing the
fuel discharged from the fuel discharging pipe 164.
A separating wall 170 having a mesh structure for
separating gases from the fuel is arranged in the
vertical annular wall 167 and the pump chamber
portion 155. The separating wall 170 extends upwardly
from a bottom face of the horizontal annular wall 168 to
the interior of the fuel intake passage 166. Therefore,
the separating wall 170 crosses the fuel passing
passage 169.
Further, the separating wall 170 extends to the
interior of the pump chamber portion 155 through the
vertical annular wall 167. Lateral sides of the
separating wall 170 in the vertical annular wall 167
extend to the inner face of the vertical annular
wall 167. Therefore, the separating wall 170 divides the
fuel intake passage 166 into two portions.
Further, the separating wall 170 extends to the
interior of the pump chamber portion 155 beyond the
horizontal wall 154b. The upper end of the separating
wall 170 in the pump chamber portion 155 is located
higher than the opening of the fuel introducing pipe 117.
Further, lateral sides of the separating wall 170 in
the pump chamber portion 155 are connected to the inner
face of the cylindrical wall of the housing 152. A
bottom end of the separating wall 170 in the pump chamber
portion 155 is connected to the horizontal wall 154b.
An operation of the fuel pump device according to
the fourteenth embodiment of the invention will be
explained below.
The fuel in the sub-tank chamber 156 is pumped into
the fuel pump 157 via the first fuel filter 158 when the
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fuel pump 157 is activated to feed the fuel in the fuel
reservoir 94 to the injectors. The fuel pumped into the
fuel pump 157 is fed to the pressure regulator 159 via
the second fuel filter 160. When the pressure of the
fuel is higher than a predetermined pressure in the
pressure regulator 159, a portion of the fuel is returned
to the sub-tank chamber 156 via the fuel returning
pipe 161. Therefore, the pressure regulator 159 and the
fuel returning pipe 161 correspond to means for
recirculating the fuel. Thus, the pressure of the fuel
is kept at the predetermined pressure.
The remaining fuel having the predetermined pressure
is fed to the injectors 120 via the fuel conveying
pipe 120.
The fuel returned to the sub-tank chamber 156 via
the fuel returning pipe 161 is discharged from the lower
tip portion 162 to the negative pressure generating
housing 163. The venturi effect of the tapered lower tip
portion 162 increases the rate of the flow of the fuel
discharging from the lower tip portion 162. The fuel
having the increased rate of the flow flows into the fuel
passing passage 169 via the fuel discharging pipe 164.
When the fuel is discharged from the lower tip
portion 162 to the fuel discharging pipe 164 to increase
the rate of the flow thereof, a negative pressure is
generated in the negative pressure generating
housing 163. Therefore, the fuel returning pipe 161 and
the negative pressure generating housing 163 correspond
to means for generating negative pressure.
The negative pressure generated in the negative
pressure generating housing 163 is introduced into the
space above the fuel surface in the reservoir 94 via the
reservoir fuel vapor pipe 150, and into the space above
the fuel surface in the sub-tank chamber 156 via the
reservoir fuel vapor and sub-tank negative pressure
introducing pipes 150 and 165. Therefore, the reservoir
fuel vapor and sub-tank negative pressure introducing
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pipes 150 and 165 correspond to means or passage for
introducing the negative pressure.
In the fourteenth embodiment, the diameter of the
reservoir fuel vapor pipe 150 is larger than that of the
sub-tank negative pressure introducing pipe 165.
Therefore, the negative pressure is introduced into the
reservoir 94 to discharge the gases including the fuel
vapor and the air from the reservoir 94 with priority.
Therefore, the sub-tank negative pressure introducing
pipe corresponds to means for facilitating the
discharging of the gases from the reservoir 94 with
priority.
When the negative pressure is introduced into the
reservoir 94, the fuel vapor and the air are discharged
from the reservoir 94 to the negative pressure generating
housing 163, and, as a result, the level of the fuel
surface in the reservoir 94 is raised to the highest
position in the fuel chamber 93. Therefore, the fuel
pump 157 corresponds to means for discharging gas from
the space formed above the fuel surface or for raising
the level of the fuel surface.
In the fourteenth embodiment, once the gases such as
the fuel vapor or the air are completely eliminated from
the reservoir 94, the reservoir 94 is kept at the
condition in which there is no gas therein as far as the
fuel pump 157 is activated. Further, when the
reservoir 94 is kept at the condition in which there is
no gas therein, the upper face of the fuel reservoir 94
represents the exact amount of the fuel in the
reservoir 94. Therefore, according to the fourteenth
embodiment, the amount of the fuel in the reservoir 94 is
exactly detected.
If the negative pressure may continue to be
introduced into the reservoir 94 after the fuel vapor and
the air have been eliminated from the reservoir 94, the
fuel may be leaked from the reservoir 94 to the reservoir
fuel vapor pipe 150. Therefore, the introducing of the
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negative pressure into the reservoir 94 should be stopped
when the fuel vapor and the air have been eliminated from
the reservoir 94.
In the fourteenth embodiment, when the fuel vapor
and the air have been completely eliminated from the
reservoir 94, and the level of the fuel surface in the
reservoir 94 reaches the fuel vapor shut off valve 149,
the valve 149 shuts off the reservoir fuel vapor
pipe 150. Therefore, the fuel vapor shut off valve 149
corresponds to means to stop introducing the negative
pressure into the reservoir 94. Further, the valve 149
corresponds to means for preventing the leakage of the
fuel from the reservoir 94.
After the fuel vapor shut off valve 149 shuts off
the reservoir fuel vapor pipe 150, the negative pressure
is introduced only into the space above the fuel surface
in the sub-tank chamber 156.
When the negative pressure is introduced into the
space above the fuel surface in the sub-tank chamber 156,
the fuel vapor and the air are discharged from the above-
mentioned space to the negative pressure generating
housing 163. The negative pressure introduced raises the
level of the fuel surface in the sub-tank chamber 156,
and the fuel is introduced from the pump chamber
portion 155 into the sub-tank chamber 156 via the fuel
intake passage 166. Therefore, the level of the fuel
surface in the sub-tank chamber 156 is kept at a
predetermined height as far as there is an amount of the
fuel in the pump chamber portion 155. Thus, when the
fuel pump device 116 is inclined and the fuel surface in
the sub-tank chamber 156 is inclined, the condition, in
which there is no fuel around the first fuel filter 158
through which the fuel is pumped into the fuel pump 157,
is prevented. Therefore, the fuel returning pipe 161 and
the negative pressure generating housing 163 correspond
to means to prevent the drying-up of the fuel.
The fuel vapor and the air discharged from the
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spaces above the fuel surfaces in the reservoir 94 and
the sub-tank chamber 156 are entrained with the fuel in
the negative pressure generating housing 163. The fuel
including the fuel vapor and the air is discharged to the
fuel passing passage 169 via the fuel discharging
pipe 164. The fuel discharged to the fuel passing
passage 169 passes through the lower opening of the fuel
intake passage 166. At this time, the fuel vapor and the
air included in the fuel move upwardly because of their
lower densities. Then, the fuel vapor and the air are
discharged from the sub-tank chamber 156 to the pump
chamber portion 155 via one of the portions of the fuel
intake passage 166 divided by the separating wall 170.
As stated above, in the fourteenth embodiment, the
fuel intake passage 166 serves as both a fuel introducing
passage for introducing the fuel into the sub-tank
chamber 156 and a fuel vapor discharging passage for
discharging the fuel vapor from the sub-tank chamber 156.
Therefore, there is no need to provide another fuel vapor
discharging passage in addition of the fuel intake
passage 166. Thus, it is possible to make the fuel pump
device small because the fuel intake passage 166
functions as the fuel introducing and fuel vapor
discharging passage.
Further, in the fourteenth embodiment, when the fuel
discharged to the fuel passing passage 169 flows under
the lower opening of the fuel intake passage 166, the
fuel passes through the separating wall 170. Therefore,
the fuel vapor and the air are separated from the fuel by
the separating wall 170 and are discharged to the pump
chamber portion 155 via the fuel intake passage 166.
Thus, the separating wall 170 corresponds to means for
separating the gases from the fuel.
Further, in the fourteenth embodiment, the fuel
passing passage 169 is directly connected to the fuel
intake passage 166, and is generally perpendicular
relative to the fuel intake passage 166. Therefore, the
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fuel vapor and the air can be easily moved up to be
separated from the fuel. Thus, the fuel passing and fuel
intake passages 169 and 166 correspond to means for
separating or discharging the gases from the fuel.
The fuel vapor discharged to the pump chamber
portion 155 is introduced into the charcoal canister 122
via the pump fuel vapor pipe 118. A lower opening of the
pump fuel vapor pipe 118 is open to the interior of the
pump chamber portion 155 adjacent to the upper wall of
the housing 152. Therefore, the fuel vapor in the pump
chamber portion 155 can be introduced into the
canister 122 until the amount of the fuel in the pump
chamber portion 155 becomes small.
The fuel in the sub-tank chamber 156 is heated by
the fuel pump 157. Therefore, the temperature of the
fuel in the sub-tank chamber 156 is higher than that of
the fuel in the pump chamber portion 155. If the fuel
having a relatively high temperature is mixed with the
fuel having a relatively low temperature in the pump
chamber portion 155, a large amount of the fuel vapor may
be generated. In addition, if the fuel flows out of the
sub-tank chamber 156 to the pump chamber portion 155 when
the amount of the fuel in the sub-tank chamber 156 is
very small, the fuel may dry up around the first fuel
filter 158. Therefore, the flow of the fuel from the
sub-tank chamber 156 to the pump chamber portion 155
should be prevented.
According to the fourteenth embodiment, the fuel
passing passage 169 is generally perpendicular relative
to the fuel intake passage 166. Therefore, the flow of
the fuel from the fuel passing passage 169 into the pump
chamber portion 155 is prevented. Thus, the fuel passing
and fuel intake passages 169 and 166 correspond to means
for preventing the flowing out of the fuel, the
generating of the fuel vapor, or the drying up of the
fuel.
The fuel in the reservoir 94 is introduced into the
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pump chamber portion 155 via the fuel introducing
pipe 117 as the fuel in the sub-tank chamber 156 is fed
to the injector by the fuel pump device 116. A portion
of the fuel introduced to the pump chamber portion 155
via the fuel introducing pipe 117 passes through the
separating wall 170. Therefore, the fuel vapor included
in the fuel in the reservoir 94 is separated in the pump
chamber portion 155.
In the fourteenth embodiment, the fuel introducing
pipe 117 is positioned at the lower position than the
bottom wall 96 of the reservoir 94. Therefore, the fuel
in the reservoir 94 can be completely introduced to the
pump chamber portion 155. Further, the upper opening of
the fuel intake passage 166 is positioned at the lower
position than the bottom face of the pipe wall of the
fuel introducing pipe 117. Therefore, the fuel in the
pump chamber portion 155 can be completely introduced to
the sub-tank chamber 156. Thus, if the amount of the
fuel in the reservoir 94 becomes small, the fuel in the
reservoir 94 can be introduced into the sub-tank
chamber 156 due to the difference in the height between
the reservoir 94 and the fuel introducing pipe 117.
When the fuel pump device 116 is inclined, the fuel
surface in the pump chamber portion 155 or the fuel
intake passage 166 may reach the lowest end of the fuel
intake passage 166. When the level of the fuel surface
exceeds the lowest end of the fuel intake passage 166 and
exceeds the lowest position of the most upper end of the
fuel intake passage 166, the fuel in the sub-tank
chamber 156 flows into the pump chamber portion 155. As
stated above, the flow of the fuel from the sub-tank
chamber 156 into the pump chamber portion 155 may lead to
the generation of the fuel vapor in the pump chamber
portion 155. Further, if the fuel flows out of the sub-
tank chamber 156 to the pump chamber portion 155 when the
amount of the fuel in the sub-tank chamber 156 is very
small, the fuel may dry up around the first fuel
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filter 158.
According to the fourteenth embodiment, the vertical
annular wall 167 extends downwardly from the horizontal
wall 154b to a relatively large extent. Therefore, it
prevents the level of the fuel surface exceeding the
lowest end of the fuel intake passage 166 and exceeding
the lowest position of the most upper end of the fuel
intake passage 166. Thus, the vertical annular wall 167
corresponds to means for preventing the fuel flowing out
or fuel vapor generating.
Further, the effect of preventing the fuel flowing
out depends only on the length or the size of the fuel
intake passage 166 (or the relationship between the
positions of the most upper and lower ends of the fuel
intake passage 166) and the inclined angle relative to
the horizon of the fuel surface in the fuel intake
passage 166. That is, the effect of preventing the flow
out of the fuel can be obtained independently of the
position of the fuel intake passage 166. Therefore, the
possible selections of the position of the fuel intake
passage 166 can be increased.
Further, in order to facilitate the separation of
the gases from the fuel discharged from the fuel passing
passage, it is desirable that the fuel stays under the
fuel intake passage for long time. According to another
embodiment as shown in Fig. 34, the fuel passing passage
is directed downwardly and is connected to the fuel
intake passage. Therefore, the fuel discharged from the
fuel passing passage flows downwardly in the fuel intake
passage. Thus, the fuel may stay under the fuel intake
passage for long time.
A fuel pump device according to the fifteenth
embodiment of the invention will be explained below.
In the fourteenth embodiment, the fuel is introduced
into the fuel pump device 116 via the fuel introducing
pipe 117 when the fuel is supplied to the reservoir 94
via the fuel feeding pipe 115. The fuel introduced into
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the fuel pump device 116 flows into the sub-tank
chamber 156. Therefore, the level of the fuel surface in
the sub-tank chamber 156 is raised.
In the fourteenth embodiment, the interior of the
reservoir 94 is in direct communication with the interior
of the sub-tank chamber 156 via the sub-tank chamber
negative pressure introducing pipe 165. Therefore, the
fuel vapor and the air may flow back to the reservoir 94
via the reservoir fuel vapor pipe 150. According to the
fifteenth embodiment, the flow of the gases from the sub-
tank chamber 156 back to the reservoir 94 while the
supply of the fuel is prevented.
In the fifteenth embodiment, as shown in Figs. 35
and 36, the sub-tank chamber negative pressure
introducing pipe 165 is not arranged in the reservoir
fuel vapor pipe 150. A sub-tank chamber negative
pressure introducing pipe 173 is arranged in the sub-tank
chamber 156 independently of the reservoir fuel vapor
pipe 150. An upper opening of the sub-tank chamber
negative pressure introducing pipe 173 is open to the
interior of the sub-tank chamber 156 at the upper area in
the sub-tank chamber 156. On the other hand, a lower
opening of the sub-tank chamber negative pressure
introducing pipe 173 is open to the interior of the
negative pressure generating housing 163. The diameter
of the lower opening of the sub-tank chamber negative
pressure introducing pipe 173 is smaller than that of the
reservoir fuel vapor pipe 150.
Components other than those described above are the
same as those of the fuel pump device according to the
fourteenth embodiment. Therefore, an explanation thereof
will not be given.
A operation of the fuel pump device according to the
fifteenth embodiment of the invention will be explained
below.
The fuel is introduced into the sub-tank chamber 156
when the fuel is introduced into the reservoir 94 via the
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fuel feeding pipe 115. Therefore, the level of the fuel
surface in the sub-tank chamber 156 is raised. In the
fifteenth embodiment, the space above the fuel surface in
the sub-tank chamber 156 is not in direct communication
with the interior of the reservoir 94. Therefore, the
flow of the fuel vapor and the air from the sub-tank
chamber 156 back to the reservoir 94 while the supply of
the fuel is prevented. Thus, the amount of the fuel
vapor and the air in the reservoir 94 is kept small
before the fuel pump 157 is activated. Therefore, the
fuel vapor and the air can be quickly eliminated from the
reservoir 94 when the fuel pump 157 is activated.
Operations other than those described above are the
same as those of the fuel pump device according to the
fourteenth embodiment. Therefore, an explanation thereof
will not be given.
In the above-mentioned embodiments, a sensor for
detecting gases including fuel vapor in the space above
the fuel surface in the fuel chamber can be used, instead
of the level switch. Further, the fuel vapor eliminating
operation may be controlled to open or close the above
mentioned shut off valves on the basis of the amount of
the gases in the fuel chamber or the volume of the space
formed above the fuel surface, instead of the highest
level of the fuel surface.
Further, the fuel vapor eliminating operation may be
controlled on the basis of the judgement if the level of
the fuel surface is higher than a predetermined level, or
if the amount of gas in the fuel chamber is larger than a
predetermined amount. Of course, in the above mentioned
embodiments, it is judged that there is an amount of gas
in the fuel chamber when the level sensor is off.
While the invention has been described by reference
to specific embodiments chosen for purposes of
illustration, it should be apparent that numerous
modifications can be made thereto by those skilled in the
art without departing from the basic concept and scope of
- 68 -
the invention.
