Fuel vapor processor diagnostic device
First Claim
1. A leak diagnostic device for use with a fuel vapor processor of an engine of a vehicle, said engine comprising a fuel tank, and said processor comprising a canister for temporarily collecting fuel vapor in said fuel tank, a normally-open air conducting valve for connecting said canister to the atmosphere, a vapor passage connecting said fuel tank and said canister, a vapor passage valve for opening and closing said vapor passage, a purge passage connecting said canister and an engine intake passage, and a purge passage valve for opening and closing said purge passage, said device comprising:
- a sensor for detecting a pressure in a space comprising any one of the vapor passage, the canister, the purge passage and the fuel tank, anda controller functioning to;
detect engine conditions for performing a leak diagnosis,introduce a test pressure different from atmospheric pressure to said space by controlling any one of said air conducting valve, vapor passage valve and purge passage valve, including closing said air conducting valve,begin said leak diagnosis of said space based on a pressure variation in said space after introducing said test pressure,detect if refueling of said fuel tank is being performed, andif refueling of said fuel tank is being performed while said leak diagnosis is being performed, control said air conducting valve so that said canister is connected to the atmosphere.
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Accused Products
Abstract
In a fuel vapor processor for use with an engine provided with a fuel tank comprising a filler tube which fits on a fuel nozzle for refueling, the presence of leaks of fuel vapor is diagnosed according to a variation of a test pressure has been introduced into a purge passage. If refueling of the fuel tank is being performed during the leak diagnosis, an escape vent for air in the fuel tank is provided by connecting the canister to the atmosphere so that smooth refueling is performed.
107 Citations
11 Claims
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1. A leak diagnostic device for use with a fuel vapor processor of an engine of a vehicle, said engine comprising a fuel tank, and said processor comprising a canister for temporarily collecting fuel vapor in said fuel tank, a normally-open air conducting valve for connecting said canister to the atmosphere, a vapor passage connecting said fuel tank and said canister, a vapor passage valve for opening and closing said vapor passage, a purge passage connecting said canister and an engine intake passage, and a purge passage valve for opening and closing said purge passage, said device comprising:
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a sensor for detecting a pressure in a space comprising any one of the vapor passage, the canister, the purge passage and the fuel tank, and a controller functioning to; detect engine conditions for performing a leak diagnosis, introduce a test pressure different from atmospheric pressure to said space by controlling any one of said air conducting valve, vapor passage valve and purge passage valve, including closing said air conducting valve, begin said leak diagnosis of said space based on a pressure variation in said space after introducing said test pressure, detect if refueling of said fuel tank is being performed, and if refueling of said fuel tank is being performed while said leak diagnosis is being performed, control said air conducting valve so that said canister is connected to the atmosphere. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A leak diagnostic device for use with a fuel vapor processor of an engine of a vehicle, said engine comprising a fuel tank provided with a filler tube for refueling and a filler cap which seals said filler tube, and said processor comprising a canister for temporarily collecting fuel vapor in said fuel tank, a normally-open air conducting valve for connecting said canister to the atmosphere, a vapor passage connecting said fuel tank and said canister, a vapor passage valve for opening and closing said vapor passage, a purge passage connecting said canister and an engine intake passage, and a purge passage valve for opening and closing said purge passage, said device comprising:
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a first sensor for detecting a pressure in a space comprising any one of the vapor passage, the canister, the purge passage and the fuel tank, a controller functioning to; detect engine conditions for performing a leak diagnosis, introduce a test pressure different from atmospheric pressure to said space by controlling any one of said air conducting valve, vapor passage valve and purge passage valve, including closing said air conducting valve, and begin said leak diagnosis of said space based on a pressure variation in said space after introducing said test pressure; and a second sensor for detecting if the filler cap has been removed, and an electrical circuit configured to forcibly open said air conducting valve if the filler cap has been removed and said leak diagnosis is being performed. - View Dependent Claims (10)
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11. A leak diagnostic device for use with a fuel vapor processor of an engine of a vehicle, said engine comprising a fuel tank and said processor comprising a canister for temporarily collecting fuel vapor in said fuel tank, a normally-open air conducting valve for connecting said canister to the atmosphere, a vapor passage connecting said fuel tank and said canister, a vapor passage valve for opening and closing said vapor passage, a purge passage connecting said canister and an engine intake passage, and a purge passage valve for opening and closing said purge passage, said device comprising:
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means for detecting a pressure in a space comprising any one of the vapor passage, the canister, the purge passage and a fuel tank, means for introducing a test pressure different from atmospheric pressure to said space by controlling any one of said air conducting valve, vapor passage valve and purge passage valve, including closing said air conducting valve, means for beginning a leak diagnosis of said space based on a pressure variation in said space after introducing said test pressure, means for detecting if refueling of said fuel tank is being performed, and means for controlling said air conducting valve so that, if refueling of said fuel tank is being performed while said leak diagnosis is being performed, said canister is connected to the atmosphere.
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Specification