Measuring and testing – With fluid pressure – Leakage
Reexamination Certificate
1999-03-04
2001-01-23
Raevis, Robert (Department: 2856)
Measuring and testing
With fluid pressure
Leakage
Reexamination Certificate
active
06176118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for diagnosing malfunction in a fuel tank.
2. Description of the Related Art
In order to prevent fuel vapor produced in a fuel tank from being discharged to the atmosphere, in a known engine, a charcoal canister containing activated carbon is provided. The vapor in a space above the surface of the fuel stored in the tank is introduced into the canister and is adsorbed on the activated carbon thereof. A large amount of the vapor, introduced into the canister, needs a large canister. Therefore, it is preferable to minimize the amount of the vapor produced in the tank in order to reduce the size of the canister.
In order to minimize the amount of vapor produced in the tank, a fuel tank which comprises a fuel-impermeable separator film in an interior of the tank, as disclosed in Japanese Unexamined Utility Model Publication No. 60-158923, has been developed. The film is in contact with the surface of the fuel in the tank to reduce the space above the fuel surface and moves up and down with the movement of the fuel surface. The small space above the fuel surface leads to a smaller amount of vapor being produced in the tank.
In the tank described above, the amount of vapor may increase if the film has problems, such as holes formed in the film, or if the film cannot move up and down as the fuel surface moves up and down. Therefore, it is necessary to diagnose the malfunction in the tank and to warn the driver of the vehicle.
Therefore, the object of the invention is to provide a device for diagnosing malfunction in the fuel tank of a vehicle.
SUMMARY OF THE INVENTION
According to the invention, there is provided, a device for diagnosing malfunction in a fuel tank, the fuel tank having a separator wall therein which separates an interior of the tank into a fuel chamber and an air chamber, the wall being deformable according to an amount of fuel in the fuel chamber, the device comprising: a device for detecting a change of at least one of a position of the separator wall, a pressure in the fuel tank and a concentration of fuel vapor in the fuel, and a device for diagnosing malfunction of the separator wall on the basis of the change to diagnose that the separator wall has malfunction when the change differs from a predetermined regular change.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a change in the pressure in the fuel tank and time elapsed since a reference time.
Further, according to the invention, the air chamber is in communication with the atmosphere, and the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a change of a pressure in the fuel tank and time elapsed since a time when the air chamber is closed to the atmosphere.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a change of a pressure in the fuel tank and time elapsed since a time when the air chamber and the fuel chamber are sealed.
Further, according to the invention, the fuel tank in communication with an engine, and the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference between pressures in the fuel tank before and after a purging operation is started to purge fuel vapor to the engine.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference in the pressure in the fuel tank before and after a refueling operation is started to supply the fuel chamber with fuel.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference in the concentration of fuel vapor before and after a refueling operation to supply the fuel chamber with fuel.
Further, according to the invention, the fuel tank in communication with an engine, and the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference in the concentration of fuel vapor before and after a purge operation to purge fuel vapor to the engine.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction when a concentration of fuel vapor is higher than a predetermined concentration.
Further, according to the invention, the fuel tank is in communication with an engine, and the malfunction diagnosing device diagnoses that the separator wall has malfunction when the concentration of fuel vapor is higher than the predetermined concentration during a purge operation to purge fuel vapor to the engine.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction when the concentration of fuel vapor is higher than the predetermined concentration during a refueling operation to supply the fuel chamber with fuel.
Further, according to the invention, the fuel tank is in communication with an engine, and the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of the change of the position of the separator wall in the fuel tank and the amount of the driving of the engine.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference in the position of the separator wall before and after a refueling operation is started to supply the fuel tank with fuel.
Further, according to the invention, the fuel tank is in communication with an engine, and the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of a difference in the position of the separator wall before and after a purge operation is started to purge fuel vapor to the engine.
Further, according to the invention, the malfunction diagnosing device diagnoses that the separator wall has malfunction on the basis of the amount of fuel in the air chamber.
Further, according to the invention, a prohibiting device is provided for prohibiting the diagnosis of the malfunction diagnosing device on the basis of at least one of an engine driving time, a temperature surrounding the fuel tank, an atmosphere pressure, and a fuel temperature in the fuel tank.
Further, according to the invention, an indicator is provided for indicating malfunction in the separator wall to indicate malfunction in the separator wall when the malfunction diagnosing device diagnoses that the separator wall has malfunction.
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.
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Hyodo Yoshihiko
Ito Taka-aki
Kidokoro Toru
Kenyon & Kenyon
Raevis Robert
Toyota Jidosha & Kabushiki Kaisha
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