PURPOSE: To eliminate delay and overcorrection of control, by controlling an air- fuel ratio controlling actuator by way of feed-back control by use of a feedback control signal obtained by using an integration constant different from that of idling operation in shifting to idling operation after stopping of the feedback control.
CONSTITUTION: Output of an O2-sensor 10 is applied via a rich-lean judging means 14 to integrators 16, 18, 30 having integration constants K0, K1, K2, respectively. The integrators 16, 18 are connected selectively to a driving circuit 28 switched by a condition judging means 20 to which the engine speed and the negative pressure in an intake pipe are applied, and they control an air-fuel ratio controlling actuator 12 by use of respective integration constants suited for idling and off-idling operations. Another condition judging means 24 functions to open a feedback stopping circuit 26 at the time of engine operation when feedback control is to be stopped, for instance, at the time of decelerating an engine and to give a signal to a condition judging means 32 when engine operation is switched to idling operation. The condition judging means 32 connects a switching circuit 34 to the integrator 30 for a while corresponding to one cycle of the O2-sensor 10.
NAKAGAWA TAKAYOSHI
NISHIGUCHI HISAO
SHIOZAWA TAKESHI
| JPS5618037A | 1981-02-20 | |||
| JPS5297031A | 1977-08-15 |