(19)
(11) EP 1 519 021 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
20.07.2005 Bulletin 2005/29

(43) Date of publication A2:
30.03.2005 Bulletin 2005/13

(21) Application number: 04023104.5

(22) Date of filing: 28.09.2004
(51) International Patent Classification (IPC)7: F02D 41/02, F02D 41/14
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL HR LT LV MK

(30) Priority: 29.09.2003 JP 2003337696

(71) Applicants:
  • Toyota Jidosha Kabushiki Kaisha
    Toyota-shi, Aichi-ken 471-8571 (JP)
  • Kabushiki Kaisha Toyota Jidoshokki
    Kariya-shi, Aichi-ken (JP)

(72) Inventors:
  • Kobayasi, Masaaki, c/o Toyota Jidosha K. K.
    Toyota-shi, Aichi-ken 471-8571 (JP)
  • Tsuzuki, Naoyuki, c/o Toyota Jidosha K. K.
    Toyota-shi, Aichi-ken 471-8571 (JP)
  • Yamaguchi, Masaaki, c/o Toyota Jidosha K. K.
    Toyota-shi, Aichi-ken 471-8571 (JP)
  • Mizuguchi, Keiichi, c/o K. K. Toyota Jidoshokki
    Kariya-shi, Aichi-ken (JP)

(74) Representative: Kuhnen, Rainer Andreas, Dipl.-Ing. 
KUHNEN & WACKER Patent- und Rechtsanwaltsbüro Prinz-Ludwig-Strasse 40A
85354 Freising
85354 Freising (DE)

   


(54) Catalyst deterioration determination apparatus of internal combustion engine


(57) In an internal combustion engine (2), during sulfur release control for permitting an exhaust purification catalyst to recover from a sulfur poisoned state, a richening period, in which fuel is supplied to exhaust gas, and a non richening period, in which no fuel is supplied to exhaust, are repeated. The ratio of the duration of the richening period to the duration of the non-richening period is changed according to the deterioration degree of the exhaust purification catalyst. Thus, even if the deterioration degree of the exhaust purification catalyst changes, an excessive increase in the catalyst bed temperature and a lowered accuracy of the sulfur release control are reliably suppressed.






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