Aisan Kogyo Kabushiki Kaisha

Tsuneo Ando

Kazusato Kasuya

Yukitoshi Asada

Hironobu Sugimoto

Takeru Yasuda

An electronic air-fuel mixture control system is adapted to an internal combustion engine to determine an optimum air-fuel ratio in dependence upon renewal of a plurality of learning values related to a plurality of load regions of the engine. The control system is arranged to conduct simultaneous learning of the learning values at a frequency in accordance with lapse of time and to conduct selective learning of the learning values in accordance with change of the load acting on the engine.

Electronic air-fuel mixture control system for internal combustion engine

An electronic air-fuel mixture control system is adapted to an internal combustion engine to determine an optimum air-fuel ratio in dependence upon renewal of plural learning values related to a plurality of load regions of the engine. The control system is arranged to select one of the learning values in accordance with the engine load and to prohibit learning of the selected learning value when a difference between the selected learning value and the adjacent learning value is more than an allowable value determined in consideration with allowable fluctuation of the air-fuel ratio caused by change of the amount of air flowing into the engine.

In a carburetor having a flow control element axially movable within an air bleed passage in the carburetor body for controlling the cross-sectional area of the passage and a stepper motor on the body for effecting axial movement of the control element, an input circuit produces an electric signal indicative of the operating condition of an engine. A computer determines rotary steps of the motor in response to the electric signal for optimizing the cross-sectional area of the passage in relation to the operating condition of the engine, an a whether the number of the determined rotary steps is more than the actual rotary steps of the motor. A first command signal and a second command signal, and first and second control signals are produced respectively for effecting one rotary step of the motor in a direction defined by each of the command signals. The computer is responsive to one of the control signals to measure a first time duration for one rotary step of the motor to produce a first time signal upon lapse of the first time duration, responsive to change of one of the command signals to the other to measure a second time duration for one reverse rotary step of the motor to produce a second time signal upon lapse of the second time duration, and further responsive to one of the time signals to selectively apply the control signals to the motor.

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Oobu, Japan

Tsuneo Ando