Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Reexamination Certificate
2000-04-04
2001-10-30
Yuen, Henry O. (Department: 3747)
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
C123S516000
Reexamination Certificate
active
06308692
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 11-104105 filed on Apr. 12, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel vapor recovery apparatus.
2. Description of the Related Art
In order to facilitate level shifts of the fuel liquid surface in a fuel tank in accordance with changes in the amount of fuel present in the fuel tank, there is a need to open the internal space of the fuel tank to the atmosphere. However, since fuel vapor normally occurs in fuel tanks, a fuel tank connected in open communication to the atmosphere allows fuel vapor to be easily emitted into the atmosphere. To solve this problem, Japanese Patent Application Laid-Open No. HEI 8-197968 proposes an apparatus in which a canister for adsorbing fuel vapor from a fuel tank is provided in a communication path between the fuel tank and the atmosphere.
The amount of fuel vapor that such a canister is able to adsorb is limited. If the fuel vapor adsorption limit is exceeded, fuel vapor passes through the canister and flows out into the atmosphere.
Therefore, the aforementioned laid-open application (HEI 8-197968) proposes a construction in which the canister is connected to an intake passage of an internal combustion engine. During operation of the engine, fuel vapor is released from the canister into the engine intake passage so that the fuel vapor adsorption limit of the canister will not be exceeded.
However, if a large amount of fuel vapor is generated in the fuel tank, or if fuel vapor adsorbed by the canister is not released into the internal combustion engine for a long time, fuel vapor passes through the canister and flows out into the atmosphere.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to prevent emission of fuel vapor into the atmosphere.
A fuel vapor recovery apparatus in accordance with the invention includes a canister for adsorbing fuel vapor generated in a fuel chamber formed in a fuel tank, wherein a fuel vapor inlet of the canister is connected to the fuel chamber and a fuel vapor outlet of the canister is connected to an intake passage of an internal combustion engine so that fuel vapor adsorbed by the canister is allowed to be purged therefrom into the intake passage. An air opening of the canister is connected to an air chamber that has a predetermined capacity. In the thus-constructed apparatus, fuel vapor flows into the air chamber having the predetermined capacity, when the amount of fuel vapor in the canister exceeds the amount of fuel vapor that can be adsorbed by the canister.
An internal space of the fuel tank may be divided into the fuel chamber and the air chamber by a partition.
The partition may be deformable so that a capacity of the fuel chamber changes corresponding to a change in an amount of fuel present in the fuel chamber.
The fuel vapor recovery apparatus may further include a valve that is provided between the air chamber and atmosphere and that opens when the air chamber has a predetermined pressure.
The air chamber may be connected to the intake passage.
The air chamber may be open to an atmosphere via a second canister that is provided for adsorbing fuel vapor.
REFERENCES:
patent: 3617034 (1971-11-01), Skinner
patent: 3977379 (1976-08-01), Weissenbach
patent: 5056493 (1991-10-01), Holzer
patent: 5460135 (1995-10-01), Ohashi et al.
patent: 5596971 (1997-01-01), Kidokoro
patent: 5746185 (1998-05-01), Kidokoro et al.
patent: 6176118 (2001-01-01), Kidokoro et al.
patent: HEI 4-362264 (1992-12-01), None
Arase Tomoyasu
Ishikawa Takashi
Gimie Mahmoud
Kenyon & Kenyon
Toyota Jidosha & Kabushiki Kaisha
Yuen Henry O.
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