(19)
(11) EP 0 657 637 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.10.1995 Bulletin 1995/41

(43) Date of publication A2:
14.06.1995 Bulletin 1995/24

(21) Application number: 94117678.6

(22) Date of filing: 09.11.1994
(51) International Patent Classification (IPC)6: F02D 41/14
(84) Designated Contracting States:
DE ES FR GB SE

(30) Priority: 12.11.1993 IT TO930857

(71) Applicant: MAGNETI MARELLI S.p.A.
I-20145 Milano (IT)

(72) Inventors:
  • Biagini, Luca
    I-42019 Scandiano (IT)
  • Serra, Gabriele
    I-40068 S. Lazzaro di Savena (IT)

(74) Representative: Cerbaro, Elena et al
c/o Studio Torta, Via Viotti 9
10121 Torino
10121 Torino (IT)


(56) References cited: : 
   
       


    (54) Electronic system for calculating fuel mixture ratio for an internal combustion engine


    (57) System for calculating mixture strength in which an electronic panel (7) is capable of comparing the voltage generated by exhaust gas sensors, in particular from a lambda probe (19) located in the exhaust manifold (21) of a petrol engine (4), with a threshold value (Str) such as to distinguish between a first and a second state (rich state/lean state), corresponding to an air/petrol mixture supplied to the engine which contains more or less petrol, respectively, than is required by the stoichiometric ratio. The system enables this threshold to be updated periodically.






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