Internal-combustion engines – Accessories – Covers – trays – vibrators – corrosion inhibitors – air filters
Reissue Patent
1993-06-02
2001-07-03
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Accessories
Covers, trays, vibrators, corrosion inhibitors, air filters
C123S520000
Reissue Patent
active
RE037250
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention generally relates to a malfunction detection apparatus for an evaporated fuel purge system in an internal combustion engine, and more particularly to an apparatus for detecting a malfunction in an evaporated fuel purge system which is provided in an internal combustion engine for purging an evaporated fuel or fuel vapor into an intake system of the internal combustion engine under given operating conditions and for adsorbing the fuel vapor in an adsorbent in a canister, so that an air-fuel mixture is fed into a combustion chamber in the internal combustion engine.
(2) Description of the Related Art
An evaporated fuel purge system is provided in an internal combustion engine for adsorbing an evaporated fuel or fuel vapor, evaporated in a fuel tank, temporarily in an adsorbent in a canister so as to prevent the fuel vapor from escaping to the atmosphere, and for purging the adsorbed fuel vapor in the canister into an intake passage of the engine during engine operation. This evaporated fuel purge system usually includes a vapor passage connecting the fuel tank to the canister and a purge passage connecting the canister to the intake system of the engine. Also, a purge control valve is provided at an intermediate portion in the purge passage. However, in a case in which the vapor passage is damaged or a connecting pipe in the vapor passage is separated due to a certain problem, the fuel vapor may escape to the atmosphere from the evaporated fuel purge system.
A conventional malfunction detection apparatus for detecting a malfunction in the evaporated fuel purge system is known. For example, Japanese Laid-Open Patent Application No.2-130255 discloses such a malfunction detection apparatus. In this conventional malfunction detection apparatus, a pressure sensor is provided in the purge passage between the canister and the purge control valve for outputting a signal indicative of pressure in the purge passage, and a malfunction in the evaporated fuel purge system is detected by the malfunction detection apparatus in response to an output signal of the pressure sensor. The malfunctions thus detected include a clogging of an air inlet of the canister, a problem in the purge control valve, a clogging of the purge passage, and a pipe separation therein. However, pressure in the vapor passage between the fuel tank and the canister is not detected by such a conventional apparatus, and there is a difficulty in that a malfunction in the evaporated fuel purge system, due to a problem in the fuel tank or a clogging of the vapor passage or a connecting pipe separation therein, is not suitably detected.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to provide an improved malfunction detection apparatus in which the above described problems of the conventional apparatus are eliminated.
Another and more specific object of the present invention is to provide a malfunction detection apparatus which can suitably detect a malfunction in any part of the evaporated fuel purge system, including a fuel tank and a vapor passage. The above mentioned object of the present invention is achieved by an evaporated fuel purge system which comprises a fuel tank in which fuel is evaporated into a fuel vapor, a canister including an adsorbent for adsorbing the fuel vapor from the fuel tank, a vapor passage connecting the fuel tank to the canister for feeding the fuel vapor from the fuel tank into the canister, a purge passage connecting the canister to an intake passage of an internal combustion engine for feeding the adsorbed fuel vapor in the adsorbent in the canister into the intake passage, a purge control valve provided at an intermediate portion in the purge passage for controlling a flow of the adsorbed fuel vapor being fed by a vacuum pressure in the intake passage from the canister to the intake passage, a pressure sensor provided at an intermediate portion in the vapor passage for outputting a signal indicative of pressure in the vapor passage, and a malfunction detection part responsive to the signal from the pressure sensor for detecting a malfunction in the evaporated fuel purge system. According to the present invention, it is possible to detect suitably a malfunction in any part of the evaporated fuel purge system by making use of the pressure sensor provided at the intermediate portion in the vapor passage, thus increasing the reliability of an evaporated fuel purge system in an internal combustion engine.
Other objects and further features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 4630581 (1986-12-01), Shibata
patent: 4641623 (1987-02-01), Hamburg
patent: 4867126 (1989-09-01), Yonekawa
patent: 4962944 (1990-10-01), Uranishi
patent: 5085194 (1992-02-01), Kuroda
patent: 5085197 (1992-02-01), Mader
patent: 26754 (1990-02-01), None
patent: 2-102360 (1990-04-01), None
patent: 130255 (1990-05-01), None
Kenyon & Kenyon
Miller Carl S.
Toyota Jidosha & Kabushiki Kaisha
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