Abstract: An air-fuel ratio of a gas mixture supplied to a vehicle engine is changed according to predetermined operating conditions. A throttle valve arranged in an intake passage to adjust an intake amount is electromagnetically controlled. If the air-fuel ratio is changed, the throttle opening characteristic for the accelerator position is changed, thereby preventing variations in engine output even if the air-fuel ratio is changed.

Abstract: Apparatus including a mixing chamber is installed between a standard carburetor base and the intake manifold of a gasoline engine. The mixing chamber includes an air inlet port for admitting a controlled amount of outside air into the mixing chamber and a gasoline vapor port for admitting gasoline vaporized externally of the carburetor into the mixing chamber, a carburetor inlet port for receiving a mixture of air and partially vaporized gasoline from the carburetor throat, and an outlet port through which a mixture of all the gases exhausts into the intake manifold. The carburetor includes a first throttle valve for controlling the air amount and partially vaporized gasoline passing into the mixing chamber. A second throttle valve controls the amount of mixed gas drawn through the mixing chamber outlet port into the intake manifold. A linkage connected to the automobile accelerator cable opens the second throttle in response to initial accelerator displacement.

Abstract: A fuel injection control system for an internal combustion engine having means for limiting a fuel amount to be supplied to the engine according to an output of an air flow sensor to a predetermined upper limit value, and means for correcting the intake air flow rate by the output of the air flow sensor when the opening of an intake air throttle valve is opened at a predetermined value, thereby limiting the output of the sensor to the predetermined upper limit value in case that the output of the sensor increases larger than the actual value and correcting the air density if different from a reference by the correcting means.

Abstract: The method comprises a couple of features: (a) late closing of an air intake valve (for a cylinder) to induce a high-velocity, air injection just before closure, and (b) admitting fuel gas into the cylinder via the air intake valve. The valving arrangement comprises a valve and a seat therefore having mating surfaces which substantially effect an initial closure of the valve on the seat at only one side of the valve. As a consequence, a high-velocity jet of air streams into the associated cylinder, via the other, later-closing side of the valve, just before full valve closure. The high-velocity air injection, the same being a purposely-directed, swirl-generating, injection, according to the method or valving arrangement, induces an enhanced air-fuel admixing in the cylinder.

Abstract: An air-fuel mixture heating device for heating an air-fuel mixture supplied from a carburetor to an intake manifold includes an insulator mounted between the carburetor and the intake manifold and having a first air-fuel mixture passage communicating with the primary air-fuel mixture passage in the carburetor, an electric heater disposed in the first air-fuel mixture passage of the insulator for heating the air-fuel mixture, and a plurality of conductors embedded in the insulator and having portions connected to the electric heater and an electric power supply. The insulator has access holes extending to the portions of the conductors for allowing said portions to be joined to the electric heater therethrough. The access holes are filled up with masses of sealing resin after said portions are joined to the electric heater.

Abstract: For a combustion procedure for internal combustion engines, in which a fuair mixture with back-fed exhaust gas is introduced into a combustion chamber, a highly-combustible fuel-air mixture without back-fed exhaust gas in introduced into at least one precombustion chamber, which is connected by means of at least one opening with the combustion chamber.

Abstract: A fuel metering apparatus having a metering chamber to hold fuel for subsequent delivery to an engine. A rigid metering member projecting into the chamber linearly movable relative to the chamber to vary the extent of projection of the metering member into the chamber to thereby control the quantity of fuel displaceable from the chamber. An inextensible flexible member secured to the metering member and a motor operated in accordance with the engine fuel demand, the motion of the motor being transmitted to the metering member through the inextensible flexible member. The inextensible flexible member is preferably adjustably coupled to the motor so the limit of movement of the metering member may be set as required.

Abstract: A fuel injection control method for an internal combustion engine wherein synchronous fuel injection is effected in synchronism with control pulses generated at predetermined crank angle positions of the engine corresponding to suction strokes of respective engine cylinders to supply the engine with a quantity of fuel required for operating conditions of the engine, and when the engine is operating in a predetermined acceleration condition, asynchronous fuel injection is effected independently of the above control pulses to supply the engine with an additional quantity of fuel. The quantity of fuel to be supplied by the synchronous fuel injection is decreased by a predetermined amount immediately after the asynchronous fuel injection is effected. The predetermined amount of fuel corresponds to the quantity of fuel to be supplied by the asynchronous fuel injection.

Abstract: An air/fuel ratio sensor apparatus which is capable of detecting deterioration of the sensing elements and correcting the output of the apparatus accordingly. The apparatus includes two sensing elements and a closed compartment of which the two sensing elements define at least portions. One of the sensing elements is used as an oxygen concentration measuring cell, and the other as an oxygen pump cell. When the internal combustion engine with which the sensor is associated is running without fuel supply, a reference voltage used for controlling the oxygen pumping current is set to a smaller value than that employed when the engine is running with a fuel supply. Deterioration of the sensing elements is then detected by comparing the output air/fuel ratio signal produced at that time with a preset fixed value.

Abstract: While an exhaust gas sensor having an output characteristic linear with respect to the concentration of a specific component in exhaust gases from an internal combustion engine, the opening of an automatic choke valve is controlled in response to the degree of warming-up of the engine. From the time of activation of the exhaust gas sensor to the time of completion of warming-up of the engine, the automatic choke valve and an air-fuel ratio control valve arranged in an air passage bypassing a throttle valve in an intake passage of the engine, are driven so as to achieve a desired air-fuel ratio, respectively, when the difference between the desired air-fuel ratio and actual one is larger than a predetermined value, and when the difference is smaller than the predetermined value. After completion of warming-up of the engine, the air-fuel ratio control valve is driven in response to operating conditions of the engine so as to achieve the desired air-fuel ratio.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in an intake passage of the engine in response to first and second control pressures supplied from a change-over control valve to the vacuum chamber.

Abstract: The invention discloses a method for detecting rotational speed fluctuations of an internal combustion engine, wherein in a first step it is checked whether the actual speed of the internal combustion engine deviates from a predeterminable desired speed by more than a predeterminable amount. In a second step, it is checked whether the time distance between two successive overtravels exceeds a predeterminable period of time; and, in a third step, it is finally determined that the rotational speed of the internal combustion engine is fluctuating if this time distance is less than the predetermined period of time. The method of the invention permits the rotational speed fluctuations of an internal combustion engine to be detected reliably while at the same time requiring little storage space and little computing time when realized by means of a computer.

Abstract: In feedback control for the air/fuel ratio based on a sensor producing an output signal proportional to a change in the air/fuel ratio, a control constant modifier is operative to vary the proportional component and the integration component in a feedback system in accordance with an air/fuel ratio set for controlling, thereby assuring stability of ultimate fuel control.

Abstract: An idle speed control method in which a feedback control for controlling the number of idle revolutions to a predetermined value, a learning control for determining a learning value needed to maintain the number of idle revolutions at the predetermined value, and an opening of the idle speed control valve are carried out. The feedback control is carried out when a predetermined feedback condition is satisfied, the learning control is carried out when a predetermined learning condition is satisfied, and the opening of the idle speed control valve is carried out when the feedback condition is not satisfied. Namely, if the present degree of opening of the idle speed control valve is larger than the learning value, the present degree of opening is maintained, and if the present degree of opening of the idle speed control valve is smaller than the learning value, the degree of opening is increased to the learning value. Also disclosed is a device for carrying out above method.

Abstract: A crank angle detecting system for a multicylinder engine includes a disc formed with a large number of slits to detect one-degree crank angular positions and a small number of slits to detect a predetermined piston stroke for each cylinder. Since the widths of a small number of slits are different from each other, it is possible to separately discriminate each cylinder in crank angular position on the basis of the crank angle signals obtained by a large number of slits. In the case where the detecting system is incorporated with a group-ignition system, it is possible to detect a predetermined piston stroke for each cylinder immediately after the engine is started, thus preventing the engine from erroneous ignition.

Abstract: An ignition timing control method for an internal combustion engine in which an ignition advance angle value conforming to the operating condition of the engine is set, an ignition timing is obtained by applying an angle-time conversion to a crank angle extending from a reference crank angle position to a position corresponding to the ignition advance angle value, and ignition is effected upon lapse of the ignition timing from an instant at which the reference crank angle position is sensed. Engine rotational speed value is sensed at least at two particular crank angle positions, and each sensed rotational speed is stored in memory. A ratio between the at least two rotational speed values stored in an immediately preceding ignition cycle is calculated, and the ignition timing of a present ignition cycle is corrected by using the calculated ratio.

Abstract: In an electronic fuel injection control device for an internal combustion engine, an A-D converter is provided to convert an analogue signal indicative of a physical value such as an intake manifold negative pressure or an amount of suction air to a digital value, and a computer is programmed to calculate an average of a plurality of the digital values successively converted during one rotation of the engine, to determine whether or not a difference between the preceding average of the digital signals and the following average of the digital signals is larger than a predetermined value indicative of a transient operation of the engine, if so determine a first optimum physical value based on an average of at least two digital values most newly converted during one rotation of the engine, and if not determine a second optimum physical value based on the average of the digital values, and to determine an optimum fuel injection time based on one of the first and second optimum physical values and in relation to r

Abstract: An ignition timing control system for an internal combustion engine comprises magnetic pick-up means for magnetically sensing the angular position of the crankshaft and for generating an output signal indicative thereof, control means for controlling the ignition timing of the engine based on the output signal from the magnetic pick-up means, and correction means for correcting the ignition timing to be controlled by the control means for a delay in the generation of the output signal, which delay increases with a rise in the rotational speed of the engine.

Abstract: An air-fuel ratio control system has a system for updating data stored in a table at a steady state of engine operation in accordance with output voltage of an O.sub.2 -sensor. When the output voltage deviates from a reference voltage corresponding to a stoichiometric air-fuel ratio during a predetermined period, the data is rewritten to a fail safe value.

Abstract: Disclosed is a centrifugal spark-advance control device for an ignition system of an internal combustion engine, comprising: a base plate which rotates at a speed corresponding to the rotational speed of the engine; a timing plate which is rotatably supported on the base plate; a spring for biasing the timing plate in a certain direction; a centrifugal weight which is pivoted to the base plate at a point spaced from the center of gravity of the centrifugal weight and which is provided with a cam surface for rotatably driving the timing plate in an opposite direction against the biasing force of the spring by cooperating with a corresponding cam follower surface provided in the timing plate; a spark generating device coupled to the timing plate for generating ignition sparks in synchronism with the rotational angle of the timing plate; a mass member attached to the timing plate by way of an elastic member.