Fuji Jukogyo Kabushiki Kaisha

Nissan Motor Company Limited

Ryuji Kataoka

Masaaki Ohgami

Mitsuo Nakamura

Takuro Morozumi

Yoshio Kanaida

Kuniji Imai

A control system is provided with a mass airflow sensor for sensing mass of intake air and for producing a mass airflow signal, an engine speed sensor for an engine speed signal proportional to the speed of the engine, and a throttle angle position sensor for producing a throttle angle signal representing the angle of the throttle valve. A first table is provided for storing first coefficients for characteristics of the injector, and a second table is provided for storing second coefficients for characteristics of the mass airflow sensor. Injection pulse width is calculated based on the mass airflow signal, engine speed signal, a read-out first coefficient and a read-out second coefficient which are dependent on the mass airflow-signal, the engine speed signal and the throttle angle signal.

Air-fuel ratio control system for an automotive engine

A system having two look-up tables, one of which is for high idle speed in a first state of a motor vehicle after starting the engine thereof and before depression of the accelerator pedal, and the other of which is for low idle speed in a second state after the accelerator pedal is depressed. The idle speed in the first state is set faster than the second state so as to provide fast idling.

System for controlling the idle speed of an automotive engine

A feedback air-fuel ratio control system for an internal combustion engine has an O.sub.2 -sensor for detecting the concentration of oxygen in exhaust gases of the engine, a coolant temperature sensor, and a circuit for disabling the feedback control operation at a low coolant temperature during warming-up of the engine. The feedback control system is also disabled when the engine is rapidly accelerated or decelerated, even if the engine is warming-up at coolant temperatures greater than the low coolant temperature state.

Air-fuel ratio control system

An air-fuel control system for an automotive engine which keeps the engine idling speed at a predetermined value. In the system, engine idling state is determined by signals from an idle-switch, and a neutral switch provided in a transmission. When the number of peaks of the fluctuating feedback signal of a feedback control circuit exceeds a predetermined value, the feedback signal is fixed to a predetermined value, so that air-fuel ratio is fixed to a value, thereby keeping the idling speed to a constant value.

A method and system for controlling the air-fuel ratio for a carburetor for an internal combustion engine having an intake passage, an exhaust passage, a throttle valve, a detector for detecting the concentration of a constituent of the exhaust gases, an on-off type electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by an air-fuel mixture supplier and an electronic controller. The electronic controller comprises a comparing circuit for comparing the output signal of the detector with a stoichiometric reference signal, for driving the on-off electromagnetic valve for controlling the air-fuel ratio to a value approximating the stoichiometric air-fuel ratio. A switch connects a constant signal generating circuit to the electronic controller and renders the electronic control means non-responsive to the detector when a vacuum sensor actuates the switch during a rapid deceleration, whereby the on-off electromagnetic valve operates by the constant signal from the constant signal generating circuit at a predetermined duty ratio to prevent an excessive enrichment of the mixture caused by misfiring.

System for controlling an air-fuel ratio

An air-fuel ratio control system for an internal combustion engine comprises an induction passage, a carburetor, an on-off type electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied to the carburetor, an O.sub.2 -sensor for detecting oxygen concentration of exhaust gases, and a feedback control circuit responsive to the output of the O.sub.2 -sensor for producing pulses for driving said electromagnetic valve for correcting the air-fuel ratio. An engine speed detecting circuit is provided for producing an output signal which varies with the engine speed; and a frequency changing circuit is provided to be responsive to the output signal of the engine speed detecting for changing the frequency of the pulses whereby the electromagnetic valve may be prevented from resonating with the vibration of the engine and with the pulsations of induced air.

An electronic control system for controlling the air-fuel ratio for an internal combustion engine comprising an oxygen sensor for detecting the concentration of oxygen in exhaust gases of the engine, an on-off type electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by an air-fuel mixture supply device, a comparator for evaluating the output signal of the oxygen sensor, an integrating and a proportional circuit connected to the comparator, and a driving circuit for producing pulses for driving the on-off type electromagnetic valve from output signals of the integrating circuit and proportional circuits for controlling the air-fuel ratio to a value substantially equal to the stoichiometric air-fuel ratio. A potentiometer-type transducer converts the operation of the throttle valve to an electric output, and a differentiating circuit differentiates the output of the transducer. The constants of the integrating and proportional circuits are increased by the differentiation signal from the differentiating circuit upon acceleration and deceleration of the engine.

A method and system for controlling the air-fuel ratio for a carburetor for an internal combustion engine having an intake passage, an exhaust passage, a throttle valve, a detector for detecting the concentration of a constituent of the exhaust gases, an on-off type electro-magnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by an air-fuel mixture supplier and an electronic controller. The electronic controller comprises a comparing circuit for comparing the output signal of the detector with a stoichiometric reference signal, for driving the on-off electro-magnetic valve for controlling the air-fuel ratio to a value approximating the stoichiometric air-fuel ratio. A switch connects a constant signal generating circuit to the electronic controller and renders the electronic control means non-responsive to the detector when a vacuum sensor actuates the switch during a rapid deceleration, whereby the on-off electro-magnetic valve operates by the constant signal from the constant signal generating circuit at a predetermined duty ratio to prevent an excessive enrichment of the mixture caused by misfiring.

An internal combustion engine has a vacuum spark timing control system to advance and retard the spark in which the spark is kept retarded until a predetermined time passes after the engine speed exceeds a predetermined reference engine speed that demarcates the high engine speed range from the low engine speed range operations. During the low engine speed range operation the spark is retarded, while during the high engine speed range operation, the spark is advanced.

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Tokyo, Japan

Ryuji Kataoka