Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Reexamination Certificate
1999-08-04
2001-07-03
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
C123S557000
Reexamination Certificate
active
06253743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a fuel vapor control apparatus for restraining fuel vapor from flowing out of a fuel tank.
2. Description of the Related Art
Fuel vaporization is promoted in a fuel tank when a space containing a relatively large amount of air exists over a surface of liquid fuel in the fuel tank. The fuel tank is connected to the atmosphere to allow the surface of liquid fuel to readily lower as fuel in the fuel tank is consumed. Therefore, fuel vaporizes in the fuel tank and fuel vapor flows out into the atmosphere, which is environmentally unfavorable. A related-art technology for reducing an amount of fuel vapor that flows out of the fuel tank into the atmosphere by cooling the fuel vapor to liquefy it and return it to the fuel tank is disclosed in, for example, Japanese Patent Application Laid-open No. HEI 6-147029.
In the technology disclosed in Japanese Patent Application Laid-open No. HEI 6-147029, the amount of fuel vapor is temporarily reduced by cooling fuel vapor extracted from the fuel tank to condense and return it to the fuel tank. However, corresponding to the reduced amount of fuel vapor, fuel vapor is generated in the fuel tank, and again flows out of the fuel tank. Therefore, it is necessary to control fuel vaporization in the fuel tank in order to restrain the outflow of fuel vapor from the fuel tank. Since fuel more readily vaporizes as the temperature in the fuel tank becomes higher, the fuel tank temperature needs to be kept low in order to restrain fuel vaporization. Therefore, in order to restrain fuel vaporization in a conventional fuel tank, energy is needed in large quantities to maintain low temperatures in the fuel tank.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to reduce the amount of fuel vapor that flows out of a fuel tank while requiring a reduced amount of energy.
In accordance with the invention, a fuel vapor control apparatus includes a fuel tank, a detector that detects a quantity of state corresponding to a concentration of fuel vapor in a space defined above a surface of liquid fuel in the fuel tank, a fuel vapor concentration determining device that determines whether a concentration of fuel vapor determined based on the quantity of state is less than a predetermined concentration, and a fuel vapor concentration increasing device that increases the concentration of fuel vapor when the fuel vapor concentration determining device determines that the concentration of fuel vapor is less than the predetermined concentration. Therefore, the concentration of fuel vapor in the fuel tank is kept higher than the predetermined concentration. Therefore, the pressure in the fuel tank when the fuel vapor concentration is higher than the predetermined concentration is lower than the pressure in the fuel tank when the fuel vapor concentration is lower than the predetermined concentration, provided that the temperature in the fuel tank remains unchanged. Hence, the possibility of outflow of fuel vapor from the fuel tank is small.
In the fuel vapor control apparatus of the invention, the fuel vapor concentration increasing device may stop increasing the concentration of fuel vapor when the fuel vapor concentration determining device determines that the concentration of fuel vapor exceeds the predetermined concentration.
The fuel vapor apparatus may further include a connection state controller that controls a state of connection between an inside of the fuel tank and an outside of the fuel tank, wherein when the fuel vapor concentration determining device determines that the concentration of fuel vapor is less than the predetermined concentration, the fuel vapor concentration increasing device increases the concentration of fuel vapor and causes air in the gas to flow from the inside of the fuel tank into the outside of the fuel tank via the connection state controller, and when the fuel vapor concentration determining device determines that the concentration of fuel vapor exceeds the predetermined concentration, the fuel vapor concentration increasing device stops increasing the concentration of fuel vapor and stops air from flowing out via the connection state controller.
The fuel vapor control apparatus may further have a construction as follows. That is, the detector may detect a pressure in the fuel tank as a quantity of state corresponding to the concentration of fuel vapor in the fuel tank. If the pressure in the fuel tank detected by the detector is higher than a predetermined pressure, the fuel vapor concentration determining device determines that the concentration of fuel vapor is less than the predetermined concentration. In another possible construction, the detector detects a fuel tank temperature as a quantity of state corresponding to the concentration of fuel vapor. If the fuel tank temperature detected by the detector is lower than a predetermined temperature, the fuel vapor concentration determining device determines that the concentration of fuel vapor is less than the predetermined concentration.
The fuel vapor concentration increasing device may include a heater device that heats fuel in the fuel tank. By using the heater device, the fuel vapor concentration can be increased. The heater device may include a fuel pump that supplies fuel from the fuel tank into an internal combustion engine. By using the fuel pump, the fuel vapor concentration can be increased.
REFERENCES:
patent: 2757744 (1956-08-01), Malone
patent: 3692823 (1972-09-01), Gordon
patent: 3800768 (1974-04-01), Rhodes et al.
patent: 4312317 (1982-01-01), Jewett et al.
patent: 4356805 (1982-11-01), Kler
patent: 4368712 (1983-01-01), Jackson et al.
patent: 5085198 (1992-02-01), Bartlett et al.
patent: 5197442 (1993-03-01), Wild et al.
patent: 5197445 (1993-03-01), Casari
patent: 5224550 (1993-07-01), Bragg
patent: 5560346 (1996-10-01), Isobe et al.
patent: 5878727 (1999-03-01), Huls
patent: 5884609 (1999-03-01), Kawamoto et al.
patent: 5921222 (1999-07-01), Freeland
patent: 5931141 (1999-08-01), Chino
patent: 5970957 (1999-10-01), Fried et al.
patent: 90 01 091 U1 (1990-04-01), None
patent: 6-147029 (1994-05-01), None
patent: 7-132738 (1995-05-01), None
patent: 8-170568 (1996-07-01), None
patent: 9-5140 (1997-01-01), None
patent: WO99/61108 A1 (1999-12-01), None
Hyodo Yoshihiko
Murai Toshimi
Sasaki Hidekazu
Takeuchi Koichi
Kenyon & Kenyon
Miller Carl S.
Toyota Jidosha & Kabushiki Kaisha
LandOfFree
Fuel vapor control apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel vapor control apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel vapor control apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541312