Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Reexamination Certificate
2002-01-28
2003-12-02
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
C123S509000
Reexamination Certificate
active
06655366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection apparatus for an outboard machine in which a fuel within a fuel tank arranged at a position apart from an engine is supplied into a vapor separator by increasing a pressure to a low pressure by means of a low pressure fuel pump, the fuel is controlled to form a fixed liquid surface within the vapor separator by a fixed liquid surface control mechanism so as to be separated into vapor and liquid, a pressure of the fuel within the vapor separator is increased to a high pressure by a high pressure fuel pump so that the fuel is supplied toward a fuel injection valve attached to a fuel distributing pipe, and a high pressure fuel is injected and supplied into an intake pipe connected to the engine via the fuel injection valve controlled by an ECU, and in particular, relates to a vapor separator provided with a high pressure fuel pump.
2. Description of the Conventional Art
The conventional vapor separator provided with the high pressure fuel pump is shown in Japanese Unexamined Patent Publication No. 8-312485. A description will be given with reference to
FIG. 3
(corresponding to a structure shown in FIGS. 22 and 23 in Japanese Unexamined Patent Publication No. 8-312485). Reference symbol V denotes a vapor separator, within which a fixed liquid surface control mechanism F is arranged. The fixed liquid surface control mechanism F is constituted of a valve seat
21
connected to a low pressure fuel flow passage
20
, a float valve
22
opening and closing the valve seat
21
and a float
25
rotatably supported by a shaft
23
and in which an arm
24
is arranged so as to face to and contact with the float valve
22
. In a low liquid surface state in which a fixed liquid surface X-X having a fixed height is not formed within the vapor separator V, the float
25
rotates in a counterclockwise direction, the float valve
22
opens the valve seat
21
and a low pressure fuel is supplied into the vapor separator V from the low pressure fuel flow passage
20
. On the other hand, in a state in which the fixed liquid surface X-X is formed within the vapor separator V, the float
25
rotates in a clockwise direction, and the float valve
22
closes the valve seat
21
so as to stop the fuel supply from the low pressure fuel flow passage
20
into the vapor separator V, thereby forming and holding the fixed liquid surface X-X within the vapor separator V. As a high pressure fuel pump PH, a wesco type pump is used. A fuel suction passage PA of the high pressure fuel pump PH is inserted and arranged within a second fuel storage
26
separated from the vapor separator V via a filter
27
. The second fuel storage
26
is held to be airtight by a seal ring
28
arranged in an upper portion thereof, and a lower portion thereof is communicated with the fixed liquid surface X-X of the vapor separator V by a communication passage
29
. The vapor separator V provided with the high pressure fuel pump PH mentioned above is structured by respective elements being connected as shown in FIG.
2
and the fuel injection apparatus of the outboard machine is thereby formed. A description will be given with reference to FIG.
2
. Reference symbol T denotes a fuel tank arranged at a position apart from the engine, the pressure of the fuel within the fuel tank T is increased to a low pressure by a low pressure fuel pump PC such as a diaphragm pump or the like, and the fuel having the low pressure is supplied toward the valve seat
21
of the vapor separator V via the low pressure fuel flow passage
20
. The low pressure fuel is supplied into the vapor separator V via the valve seat
21
, and a fixed liquid surface X-X is formed and held in the inner portion by the fixed liquid surface control mechanism F. The fuel stored within the vapor separator V is supplied into the second fuel storage
26
via the communication passage
29
, the fuel stored within the second fuel storage
26
is sucked into the high pressure fuel pump PH via the filter
27
and the fuel suction passage PA, the pressure thereof is increased to a high pressure in the pump portion, and the fuel having the high pressure is supplied into a fuel distribution pipe D via a fuel discharge passage PB and a high pressure fuel flow passage
30
. A part of the high pressure fuel supplied into the fuel distribution pipe D is circulated into the vapor separator V via a return fuel passage
31
, and a fuel pressure within the fuel distribution pipe D is controlled to a predetermined fixed fuel pressure in accordance with a regulating effect of a pressure regulator R arranged within the return fuel passage
31
. Further, the fuel having the predetermined pressure is injected and supplied into an intake pipe K connected to the engine E via the fuel injection valve J.
In accordance with the conventional vapor separator provided with the high pressure fuel pump mentioned above, it is hard to continuously supply a stable and accurate fuel into the intake pipe K from the fuel injection valve J, and a good operation of the engine is impeded. That is, a wesco type pump is frequently used as the high pressure fuel pump PH since a discharge pulsation is a little and a compact and light structure can be achieved. The wesco type pump is structured, as shown in
FIG. 3
, such that an impeller PD driven by a motor M is rotatably arranged within a pump chamber PC, and when a rotational force is transmitted to the impeller PD due to a rotation of the motor M, a pressure difference is generated between the front and the rear of a vane groove formed on an outer periphery of the impeller PD on the basis of a liquid friction, the pressure of the fuel within the pump chamber PC is increased by the repetition of the above operation in a multiplicity of vane grooves, and the high pressure fuel having thus the increased pressure is discharged out via the fuel discharge passage PB. On the other hand, on the basis of a rotation of the impeller PD within the pump chamber PC, the fuel pressure within the pump chamber PC is reduced, whereby bubbles are generated, and the bubbles are discharged out of the pump chamber PC via a vapor discharge port PE pierced so as to open toward a bottom portion of a cover from the pump chamber PC. If the vapor stays within the pump chamber PC without being discharged, the bubbles gradually accumulate to become bigger, and a vapor lock is generated and the pump operation is impeded. Further, the bubbles containing the fuel discharged from the vapor discharge port PE is discharged into the second fuel storage
26
, the upper opening of the second fuel storage
26
is sealed with a sealing
28
at this time, and the bubbles stay within the second fuel storage
26
because the second fuel storage
26
is in a closed state. Further, when a fixed amount of the bubbles stay, the bubbles are sucked into the pump chamber PC via the filter
27
. In accordance with the structure mentioned above, the bubbles are contained in the fuel discharged from the high pressure fuel pump PH, and when the fuel containing the bubbles is injected from the fuel injection valve, an amount of injection from the fuel injection valve J is reduced in correspondence to the bubbles, so that it is impossible to supply an accurate fuel from the fuel injection valve J. Further, since the bubbles are contained in the fuel, the fuel supply is intermittently carried out, so that in any cases, an operability of the engine is deteriorated. Further, in the case that a large amount of bubbles stay within the pump chamber PC, there is a risk that the pump operation by the impeller can not be executed.
Further, paying attention to the vapor separator, a return fuel drops and flows into the vapor separator V via the return fuel passage
31
while the low pressure fuel drops and flows into the vapor separator V via the valve seat
21
. Accordingly, since the bubbles are sucked into the fuel stored within the vapor separator V, the bubbles scatter in the fuel within the vapor separator V. Further,
Gimie Mahmoud
Keihin Corporation
Sheets Kendal M.
Zito Joseph J.
Zito tlp
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