PURPOSE: To prevent an engine from a hatching phenomenon and stoppage of rotation by controlling air fuel ratio with open loop control in cylinder reducing running.
CONSTITUTION: There are provided a number-of-cylinders controlling means (a) for controlling the number of cylinders to which fuel is supplied according to the running condition of an engine b and a feedback control means c for feedback control of fuel supply amount on the basis of the output of an exhaust sensor e provided in an exhaust path d. And in a period of cylinder reduction when the number of cylinders to which fuel is supplied is reduced by the number-of-cylinders controlling means (a), and at least in idling, the feedback control is stopped and fuel supply amount is subjected to open loop control by the open loop control means f on the basis of a predetermined value. Thus, the air fuel ratio can be stably controlled in the number-of-cylinder reducing running and idling so that hatching phenomenon of the engine, etc. can be prevented, and controlled without responsive lag by the feedback control of air fuel ratio in all cylinder running.
MATSUURA MASAHIKO
ODA HIROYUKI
| JP54165616B |
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