Internal-combustion engines – Charge forming device – Fuel flow regulation between the pump and the charge-forming...
Reexamination Certificate
1998-09-23
2001-02-06
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel flow regulation between the pump and the charge-forming...
C123S514000
Reexamination Certificate
active
06182640
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fuel supply unit for supplying fuel to a fuel supply system of an engine from a fuel tank mounted on a vehicle such as a motorcycle.
2. Description of Background Art
Japanese Patent Laid-Open Publication No. Sho. 63-227949 discloses a fuel supply unit for a vehicle, in which a fuel tank houses a subsidiary tank, which encloses a fuel pump. A fuel return pipe communicates with the fuel pump via an open end thereof.
FIG. 6
schematically illustrates the configuration of a fuel supply unit including an in-tank type fuel pump that is applied to a motorcycle.
Referring to
FIG. 6
, a fuel pump
2
is housed in a fuel tank
1
at a rear bottom thereof, and is connected at its inlet port
3
to a strainer
4
having a resin mesh filter for removing foreign matter. A discharge pipe extends from a discharge port of the fuel pump
2
for introducing fuel to a throttle body
7
outside the fuel tank
1
via a high pressure fuel filter
6
. The fuel is then injected by fuel injectors into combustion chambers of the engine. Part of the fuel is returned as surplus fuel to an area near the strainer
4
by a pressure regulator
9
of the throttle body
7
via a connecting hose
10
a
and a fuel return pipe
10
.
In the foregoing related art, the fuel returned via the fuel return pipe contains a lot of gases. The fuel pump draws up such returned fuel when the fuel in either the fuel tank or the subsidiary tank is nearly reduced to a lower limit. Therefore, the engine sometimes suffers from a surge. In such a case, the mesh filter in the strainer does not contribute to separation of gases from the fuel.
When accelerating, decelerating or turning, a motorcycle changes its posture extensively compared with a four-wheel vehicle. In such a case, the motorcycle engine tends to suffer from surge because the level of the fuel varies in the fuel tank. There has been a strong demand for preventing the surge caused by the foregoing reasons.
SUMMARY AND OBJECTS OF THE INVENTION
In order to overcome the foregoing problems, the invention provides a fuel supply unit according to a first aspect, which comprises: a fuel tank; a fuel pump for providing a fuel supply system of a vehicle with fuel introduced from the fuel tank via a strainer disposed therein; a fuel return pipe for returning surplus fuel from the fuel supply system to said fuel tank; and a spongy fuel-adsorbing member disposed between the strainer and a tip of the fuel return pipe.
The fuel-adsorbing member is made of a spongy material which is full of minute pores and is elastic and flexible, can attract fuel thereonto, and can separate gases from the returned fuel. The fuel-adsorbing member may be constructed of a natural material, a foamed synthetic resin material, or a metallic material. For example, it may be made of a corrosion-resistant metal. In the specification, the terms “forward direction” and “rear direction” represent the directions in which the vehicle is operated, and “upward direction” and “downward direction” represent the directions with respect to a standing position of the vehicle.
In the fuel supply unit according to a second aspect, the partition is disposed in the fuel tank in order to separate at least an area near the inlet port of the fuel pump and the area in front of the inlet port. The fuel-adsorbing member is supported by the partition.
According to a third aspect of the invention, the fuel supply unit is designed for a motorcycle.
According to the first aspect, the spongy fuel-adsorbing member is disposed between the strainer and the tip of the fuel return pipe, thereby enabling the air-fuel mixture returned via the fuel return pipe to be separated into gases and liquid fuel. The liquid fuel is adsorbed onto the fuel-adsorbing member and usually stays near the strainer. Even when the amount of fuel is reduced nearly to the lower limit, it is possible to supply the foregoing liquid fuel to the fuel tank from the adsorbing member, so that the engine can be protected against a surge. Further, the liquid fuel adsorbed onto the fuel-adsorbing member remains around the strainer, which allows the fuel to be supplied substantially without being affected by the varying posture of the vehicle during operation.
The fuel-adsorbing member is easily manufactured using a spongy material such as a foamed synthetic resin material which is elastic, so that it is resistant to vibrations and effective in suppressing noise. Alternatively, a fuel-adsorbing member made of a corrosion-resistant metal and having good heat conductivity is sufficiently durable with respect to returned acidic fuel, and can cool the adsorbed fuel.
In accordance with the second aspect of the invention, the partition in the fuel tank divides at least the area near the inlet port of the fuel pump and the area in front of the inlet port. Therefore, even if the vehicle is suddenly decelerated due to braking, a fuel level can be maintained substantially normal near the inlet port of the fuel tank, thereby protecting the engine against surge. Further, the fuel-adsorbing member supported on the partition can be easily arranged near the strainer.
When the fuel supply unit is applied to the motorcycle whose posture is extensively variable during operation, the engine thereof can be protected against surge according to the third aspect-of the invention. Therefore, the fuel supply unit is preferable for use with motorcycles.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4279332 (1981-07-01), Schuster
patent: 4767632 (1988-08-01), Andreasson
patent: 4974570 (1990-12-01), Szwargulski
patent: 5427074 (1995-06-01), Tuckey
patent: 5560342 (1996-10-01), Fournier
patent: 5579740 (1996-12-01), Cotton
patent: 5797376 (1998-08-01), Frank et al.
patent: 5797378 (1998-08-01), Kato
patent: 5894857 (1999-04-01), Takaki
patent: 0743445 A1 (1996-11-01), None
patent: 63-227949 (1988-09-01), None
Dazai Masayuki
Nakashima Tai
Ono Nobuo
Yoshiki Hiroto
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Miller Carl S.
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