Fuji Jukogyo Kabushiki Kaisha

Nissan Motor Company Limited

Van Doorne's Transmissie B.v.

Masaaki Ohgami

Fujio Matsui

Hiroyuki Nakamura

Kazuo Hara

Makoto Shikata

Hitoshi Suzuki

Mitsuo Nakamura

Masaharu Kubota

Yoshiaki Kasai

Hiroki Yasuda

Yoshiaki Ohara

Tetsuo Satoh

Shoji Ogata

Kunihiro Abe

Ichiro Kudo

Takuro Morozumi

Masayuki Kodama

Ryuji Kataoka

An air-fuel ratio control system for a carburetor of an internal combustion engine comprises an O.sub.2 -sensor for detecting the concentration of the oxygen constituent of exhaust gases passing through an exhaust passage, an on-off electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by the carburetor, an electronic control circuit comprising a comparator for comparing an output signal of the O.sub.2 -sensor, an integration circuit, and a driving circuit for producing driving pulses for driving the electromagnetic valve in dependency on an output signal of the integration circuit for controlling the air-fuel ratio. A detector, such as an ignition pulse generating device, is provided for detecting conditions of operation of the internal combustion engine and for producing an engine operation signal, and a current control circuit responds to the engine operation signal for producing an output current. A delay circuit is provided to respond to the output current for delaying the output signal of the integration circuit.

Air-fuel ratio control system

An infinitely variable transmission has a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, and a belt engaged with both pulleys. A hydraulic circuit having a transmission ratio control valve is provided for shifting the disc of the primary pulley in the downshift direction and upshift direction. The transmission ratio control valve is operated to shift the disc of the primary pulley in the downshift direction when the throttle valve of the engine is rapidly opened for accelerating the engine.

System for controlling the transmission ratio of an infinitely variable

A system for controlling power transmission of a four-wheel drive vehicle having main driving wheels of the vehicle powered by an engine. A clutch transmits the power of the engine to auxiliary driving wheels of the vehicle so as to provide forward drive. A transmitter transmits a high frequency wave to a surface of a road in front of the vehicle and a receiver receives the reflected wave. A comparator is provided for comparing the received wave with the transmitted wave. When the difference between the amplitudes of both waves exceeds a reference value, a control circuit engages the clutch for the four-wheel drive.

Four-wheel drive vehicle

A system for controlling the transmission ratio of an infinitely variable transmission has a primary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a secondary pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc and a belt engaged with both pulleys, and a hydraulic circuit. The system further comprises a transmission ratio control valve for controlling the fluid applied to the hydraulic cylinder of the primary pulley and for shifting the disc of the primary pulley, and devices for detecting conditions of engine operation and for producing electrical signals. An electric control unit responds to the electrical signals to produce control signals. A solenoid operated valve is provided to respond to the control signals to control the transmission ratio control valve so as to control the transmission ratio by the pulleys.

An engine speed control system for an internal combustion engine mounted on a vehicle comprises an actuator for actuating a throttle valve for increasing and decreasing the idling speed, an ignition switch for producing a signal during the operation of the engine, an engine speed signal generating circuit, an engine speed increasing signal generating circuit and an engine speed decreasing signal generating circuit, an actuator control circuit for operating the actuator in opposite directions in accordance with engine speed increasing and decreasing signals, a vehicle speed signal generating circuit, and an idling signal generating circuit for generating an idling signal in the idling operation of the engine. A stop switch is provided for producing a signal when the throttle valve reaches the closed position. A logic gate means is provided to be operated by the vehicle speed signal, idling signal, signal of the ignition switch and signal of the stop switch for turning off the actuator control circuit for stopping the operation of the actuator.

Engine speed control system

Speed detectors are provided for detecting speeds of each of the four wheels of a vehicle. An electric circuit is provided to compare the speeds of all wheels and to turn on at least one lamp when a difference between individual wheel speeds is detected, whereby slipping of wheels is indicated.

Slip indicating system for a four-wheel drive vehicle

A feedback control system in which the error signal is oscillated by a dither signal having a periodical pattern for oscillating the controlled output. The dither signal comprises a plurality of positive excursions and negative excursions, and at least one of the positive excursions is lower than the others and at least one of the negative excursions is shallower than the others. The dither signal is applied to an actuator to produce a controlled output. A detector senses the value of the controlled output caused by the operation of the actuator. The detector is adapted to produce an output signal in which portions corresponding to at least the low positive excursion or negative excursion of the dither signal are removed when the controlled output deviates from a desired value in different directions. A comparing circuit compares the output signal of the detector with a standard signal value. The output signal of the comparing circuit is fed to a shift signal generating circuit for shifting the dither signal for correcting the deviation of the controlled output. An amplitude control circuit is provided for reducing the amplitude of the dither signal when the comparing circuit produces a signal representing a condition of the controlled output in a central range with respect to the desired value so that the amplitude of the controlled output can be reduced.

Control system

An air-fuel ratio control system for an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the operation of the engine. A throttle sensor for detecting acceleration of the engine and a predetermined voltage supply device are provided. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in a normal operating condition and for stopping the control operation when the acceleration of the engine is detected by the throttle sensor. A first switch is provided to be actuated by the output of the throttle sensor to connect the output of the predetermined voltage supply with the input of the feedback control circuit when acceleration is detected. A second switch is provided to be actuated by the output of the throttle sensor to render the feedback control circuit inoperative as a feedback controller, whereby the air-fuel ratio is controlled by the output of the predetermined voltage supply.

An engine idling speed control system for an internal combustion engine comprising an actuator for actuating a throttle valve for increasing and decreasing the idling speed, an engine speed signal generating circuit, an engine speed increasing signal generating circuit and an engine speed decreasing signal generating circuit, a vehicle speed detecting circuit for generating a signal when the vehicle speed is lower than a predetermined value, an idling signal generating circuit for generating an idling signal in the idling operation of the engine, an engine speed detecting circuit for producing a signal when the engine speed is higher than a predetermined value, and an actuator control circuit for operating the actuator in opposite directions in accordance with engine speed increasing and decreasing signals. A logic gate circuit is provided to be operated by the signal from the vehicle speed detecting circuit, idling signal and signal from the engine speed detecting circuit for enabling the engine speed increasing and decreasing signals for performing an automatic idling speed control.

An air-fuel ratio control system for an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the operation of the engine. A throttle sensor for detecting a wide-open throttle operation of the engine and a predetermined voltage supply circuit are provided. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in a normal operating condition. A memorizer circuit memorizes a value corresponding to the control output of the feedback control circuit. A first switch means is actuated by the output of the throttle senor to connect the output of the predetermined voltage supply circuit with the input of the feedback control circuit when acceleration is detected, and to cut off the input of the memorizer circuit for maintaining the stored content thereof. A second switch circuit actuated by the output of the throttle sensor to render the feedback control circuit inoperative as a feedback controller, whereby the air-fuel ratio is controlled by the output of the predetermined voltage supply circuit. After the wide-open throttle operation, the feedback control circuit re-starts with the stored content in the memorizer circuit.

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.

A feedback control system in which the error signal is oscillated by a dither signal having a periodical pattern for oscillating the controlled output. The dither signal comprises a plurality of positive excursions and negative excursions, and at least one of the positive excursions is lower than the others and at least one of the negative excursions is shallower than the others. The dither signal is applied to an actuator to produce a controlled output. A detector senses the value of the controlled output caused by the operation of the actuator. The detector is adapted to produce an output signal in which portions corresponding to at least the low positive excursion or negative excursion of the dither signal are removed when the controlled output deviates from a desired value in different directions. A comparing circuit compares the output signal of the detector with a standard signal value. The output signal of the comparing circuit is signal for detecting the removed portions. The output signal therefrom is fed to a shift signal generating circuit for shifting the dither signal for correcting the deviation of the controlled output. An amplitude control circuit is provided for reducing the amplitude of the dither signal when the comparing circuit produces a signal representing a condition of the controlled output in a central range with respect to the desired value so that the amplitude of the controlled output can be reduced.

A system for electronically detecting the transient state of engine operation of an internal combustion engine having a spark ignition system. A measuring circuit counts pulses having the pulse separation of the ignition timing of the spark ignition system and produces data output. A plurality of memorizing circuits are provided for memorizing old data output from the measuring circuit and a subtractor compares the old data output and the memorizing circuit with the new data output from the measuring circuit and produces the difference between the data and the amount of the difference. The output of the subtractor is used for correcting the air-fuel ratio of the air-fuel mixture of an emission control system using a three-way catalytic converter.

System for detecting the transient state of engine operation

An instructing system for a four-wheel drive vehicle powered by an internal combustion engine comprises a transmission for transmitting power from the engine to two main driving wheels, a clutch for selectively transmitting the power to auxiliary two-wheels, and a select lever for engaging the clutch. Speed detectors are provided for detecting both the speed of the two main driving wheels and the two auxiliary wheels. An electric circuit compares both speeds and turns on a lamp when the difference between both speeds exceeds a predetermined level, whereby slipping of the two main driving wheels is indicated.

Instructing system for a four-wheel drive vehicle

An air-fuel ratio control system for an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the temperature of the engine and operation of the engine. A temperature sensor for detecting the engine temperature and a negative pressure sensor for detecting the engine manifold vacuum in the induction passage are provided. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in a normal operating condition and for stopping the control operation when the acceleration in the cold engine is detected by the temperature sensor and the negative pressure sensor. A first switch is provided to be actuated by the output of the negative pressure sensor to connect the output of the temperature sensor with the input of the feedback control circuit when the negative pressure is lower than a predetermined value. A second switch is provided to be actuated by the output of the negative pressure sensor to render the feedback control circuit inoperative as a feedback controller, whereby the air-fuel ratio is controlled by the output of the temperature sensor.

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Musashino, Japan

Masaaki Ohgami