(19)
(11) EP 0 296 323 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
25.01.1989 Bulletin 1989/04

(43) Date of publication A2:
28.12.1988 Bulletin 1988/52

(21) Application number: 88106047.9

(22) Date of filing: 23.11.1983
(51) International Patent Classification (IPC)4: F02D 31/00
(84) Designated Contracting States:
DE FR GB

(30) Priority: 24.11.1982 JP 204667/82

(62) Application number of the earlier application in accordance with Art. 76 EPC:
83111717.1 / 0110312

(71) Applicant: HITACHI, LTD.
Chiyoda-ku, Tokyo 101 (JP)

(72) Inventors:
  • Kashiwaya, Mineo
    Katsuta-shi (JP)
  • Morita, Kiyomi
    Katsuta-shi (JP)
  • Sakamoto, Masahide
    Katsuta-shi (JP)

(74) Representative: Beetz & Partner Patentanwälte 
Steinsdorfstrasse 10
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Engine control method


    (57) In an engine control system comprising a plurality of sensors including a throttle opening sensor for detecting the closed state of a throttle valve, a method comprising the steps of judging wether the engine speed has decreased or not to a predetermined engine speed which is higher than a desired engine speed in an engine idle operation, when said throttle valve has been closed, and in a case that it is judget that the engine speed has decreased to said predetermined engine speed, the duty cycle of a bypass valve being controlled in accordance with the pulse from a pulse generating circuit when the real engine speed becomes lower than said predetermined engine speed.







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