(19)
(11) EP 1 215 386 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.01.2004 Bulletin 2004/04

(43) Date of publication A2:
19.06.2002 Bulletin 2002/25

(21) Application number: 01129734.8

(22) Date of filing: 13.12.2001
(51) International Patent Classification (IPC)7: F02D 41/22, F02D 41/14, F02D 41/34, F02D 41/38
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 15.12.2000 JP 2000381626

(71) Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
Aichi-ken 471-8571 (JP)

(72) Inventor:
  • Morikawa, Atsushi, Toyota Jidosha Kabushiki Kaisha
    Toyota-shi, Aichi-ken 471-8571 (JP)

(74) Representative: Leson, Thomas Johannes Alois, Dipl.-Ing. 
Tiedtke-Bühling-Kinne & Partner GbR, TBK-Patent, Bavariaring 4
80336 München
80336 München (DE)

   


(54) Apparatus and method for diagnosing fuel supply system of internal combustion engine


(57) Apparatus and method for diagnosing a fuel supply system of an internal combustion engine wherein a compensation amount (qcy) for each cylinder is determined on the basis of a deviation (DNE) of an actual operating state of the engine with respect to a desired operating state thereof, and the fuel supply system is feedback-controlled by compensating a commanded value (QFIN) of a quantity of injection of a fuel by the fuel supply system into the internal combustion engine, according to the compensation amount. The apparatus and method include respectively include a diagnosing device (52) and a diagnostic step for effecting a diagnostic compulsory adjustment (in steps S590 and S600) of an operating condition of the fuel supply system for each cylinder when the absolute value of the compensation amount (qcy) exceeds a predetermined threshold (A) (when affirmative decision is obtained in step S550), and for diagnosing the fuel supply system on the basis of a speed variation of the engine cause by the adjustment.






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