Abstract: A pressure sensor is provided in a fuel supply line for detecting fuel pressure for generating a pressure signal. The pressure signal is compared with a predetermined pressure value dependent on operating conditions of an engine. Amount of fuel injected into the engine is decreased when the pressure signal is higher than the predetermined pressure value, or the amount of fuel is increased when the pressure signal is lower than the predetermined pressure value for effectively preventing the engine from damaging.

Abstract: A system for avoiding the effects of jerking in the drive train of a motor vehicle driven by an internal combustion engine, comprising a device for limiting the quantity of fuel supplied to the combustion chambers of the engine controlled with the aid of a transducer for measuring the approach of two coupling parts of a coupling mounted in the drive shaft to the gearing system of the motor vehicle. If a value of a predetermined approach speed is exceeded, then the drive torque output by the engine is reduced, by reducing the fuel quantity, such that the coupling parts come into contact gently with one another. After that, the output torque of the engine can be further increased arbitrarily.

Abstract: Fuel injection pump for internal combustion engines comprising a displacement pickup for determining the position of control elements arranged in a pump housing. The displacement pickup comprises a movable part, which is arranged in the pump housing and is connected with the control element, and a stationary part which is arranged on the outside of the pump housing. The position of the movable part of the displacement pickup is determined by the stationary part by means of a measuring process which measures in a contactless manner, e.g. by means of the induction or eddy current principle.

Abstract: In a fuel injection pump system for internal combustion engines includes a fuel pump whose pump plunger (14) executes an axially reciprocating and rotating movement, and a switching valve (29) which is controlled by a computerized control device (34) and whose closing period determines the start of delivery and the desired delivery stroke of the pump plunger (14) which effects fuel injection. The desired delivery stroke is calculated by a control computer (35) of the control device (34) according to the instantaneous operating parameters of the internal combustion engine. A stroke transmitter (36) is provided for direction controlling the start of delivery and the end of delivery by means of the pump plunger stroke, the stroke transmitter (36) senses the stroke of the pump plunger (14) and applies it to the control device (34) as an actual delivery stroke signal.

Abstract: A method for controlling an internal combustion engine employing an exhaust gas recirculation system wherein a fuel injection amount is controlled corresponding to a calculated cylinder air mass flow rate and the method comprises the steps of: deriving a flow rate of a recirculated exhaust gas flowing into an induction passage of the engine; predicting a partial pressure of the exhaust gas within the induction passage on the basis of the flow rate of the recirculated exhaust gas; and deriving the cylinder air mass flow rate on the basis of the predicted value of the partial pressure of the recirculated exhaust gas.

Abstract: An apparatus is provided for operating an internal combustion engine having an inlet air filter and a plurality of solenoid operated fuel injection units adapted to receive fuel injection signals and responsively inject fuel into associated engine cylinders. The apparatus includes a sensor adapted to sense a level of clogging of the air filter and responsively produce a clogging level signal. An electronic controller is adapted to produce the fuel injection signals as a function of sensed operating parameters and in accordance with a preselected horsepower curve. The controller is further adapted to receive the clogging level signal, compare the clogging level signal to a preselected threshold and limit the maximum engine horsepower in response to the clogging level signal being equal to or greater than the preselected threshold.

Abstract: A fuel injection nozzle for a combustion engine not only has a valve for alternately opening and closing the nozzle, but also has a part which undergoes alternating stroke movement, either longitudinally or transversely. The alternating stroke movement changes the opening angle of the nozzle opening. The alternating stroke movement is in a frequency range of approximately 5 to 20 kiloHertz.

Abstract: A fuel blending ratio detecting method is provided which includes a feedback computing compensation coefficient K.sub.FB on the basis of an air/fuel ratio responsive output V.sub.o of an O.sub.2 sensor, computing a feedback learned value K.sub.LRN on the basis of the feedback compensation coefficient K.sub.FB at intervals of a predetermined period, and multiplying the current blending ratio compensation coefficient K.sub.B by this feedback learned value K.sub.LRN to compute the next blending ratio compensation coefficient K.sub.B. Thus, the quantity of fuel supplied to the internal combustion engine can be always controlled accurately on the basis of the computed blending ratio compensation coefficient.

Abstract: A position sensor for a valve or the like includes a first electrode disposed about the valve or a member associated therewith in a manner that the interfacial area betwen the valve and the electrode remains constant irrespective of the position of the valve. One or more second electrodes are disposed in a manner that the interfacial area between the valve and the electrode varies with the position of the valve. By sensing the change in electrostatic capacity between the electrodes the position of the valve may be detected. The sensor finds application in a fuel injection pump wherein it permits a very compact solenoid (motor)/sensor arrangement.

Abstract: A system for sensing the nature of gasoline is disclosed, which comprises a capacitance type sensor for producing a first information signal representative of the dielectric constant of the gasoline; a temperature sensor for producing a second information signal representative of the temperature of the gasoline; a temperature coefficient deriving device for deriving a temperature coefficient of the gasoline from the first and second information signals; an additive concentration deriving device for deriving the concentration of alcohols in the gasoline from the temperature coefficient; a correcting device for correcting the first information signal in view of a reference temperature; and a judging device for judging the nature of the gasoline from the derived concentration of the additive and the corrected first information signal.

Abstract: In the disclosed embodiments, a fuel supply system for an internal combustion engine operating on alcohol-containing fuel has a fuel pump and a cold-starting device for injecting an auxiliary fuel into an air-fuel intake line of the engine. A control unit controls the operation of the cold-start device when the temperature is lower than a predetermined lower temperature limit and the actuation time is adjustable as a function of temperature. The actuation time of the cold-start device is also controllable as a function of the alcohol content of the fuel.

Abstract: A system according to the invention controls the vaporized amount of a blended fuel composed of gasoline and an alcohol such as methanol and contained in a fuel tank mounted at a vehicular internal combustion engine. The methanol concentration in the fuel is sensed and from the sensed value, reid vapor pressure of the fuel is presumed. The pressure in the fuel tank is then regulated at a target pressure by adjusting the amount of vaporized fuel to be removed from the fuel tank and fed to a canister in response to the presumed reid vapor pressure.

Abstract: A combustion/evaluation apparatus having a sampling member for sampling light emitted from flame in an internal combustion engine, optical fibers for separating the light sampled by the sampling member into at least two lights, optical filters for selectively transmitting lights having different wavelengths by being provided in optical paths for the separated lights, photoelectric conversion elements for respectively converting optical signals transmitted through the optical filters into electrical signals, and a calculation/evaluation unit for calculating an air ratio and a temperature for evaluation of the combustion condition of the flame by using a ratio of outputs from the photoelectric conversion elements, and for evaluating the combustion condition on the basis of the air ratio and the temperature.

Abstract: Flow rate measuring method and apparatus for determining a flow rate of a fluid flowing through a pipe by using a fuzzy inference system which is operative on the basis of fuzzy knowledge including fuzzy rules each described in the form of an IF part and a THEN part, and membership functions defining meanings of statements described in said IF and THEN parts. Flow velocity of the fluid is measured at a plurality of locations within the pipe by a plurality of sensors. A table of membership functions indicating grades of fitness of the flow velocities to a distorted flow model distribution is provided in a storage together with a mean flow rate calculating expression for deriving a flow rate corresponding to the distorted flow model distribution.

Abstract: An apparatus for discriminating between different types of alcohol contained in alcohol-gasoline fuel mixtures, such as methanol or ethanol, and a fueling system for controlling the quantity of alcohol-gasoline fuel mixture delivered to an internal combustion engine in accordance with type of alcohol determined to be present in the fuel mixture are described. The resistivity of the fuel mixture delivered to the engine is measured using a fuel resistance sensor. Based upon the measured resistivity, the type of alcohol contained in the fuel mixture is determined and indicated. The fuel system then adjusts the quantity of the fuel mixture delivered to the engine based upon the indicated type of alcohol and the sensed alcohol concentration in the fuel mixture.

Abstract: An evaporative fuel-purging control system for an internal combustion engine, which controls purging of a mixture of evaporative fuel from a fuel tank and air comprises a purge control valve arranged across a purging passage for controlling the flow rate of evaporative fuel from the fuel tank to an intake passage. The flow rate of evaporative fuel is detected and compared with a desired flow rate commensurate with an operating condition of the engine. The valve opening of the purge control valve is controlled in response to results of the comparison. The change rate of the valve opening is varied according to the concentration of evaporative fuel in the mixture. Specifically, the change rate is decreased as the evaporative fuel concentration is higher.

Abstract: A fuel injection device for an internal combustion engine having a fuel injector connected to a discharge port of a fuel supply pump, via a fuel passage, wherein a fuel pressure drop detecting unit detects a drop in the fuel pressure in the fuel passage caused by a plurality of fuel injections, while a fuel supply unit has stopped the supply of fuel from the fuel supply pump to the fuel passage, and a correction unit corrects an amount of fuel to be injected, to thereby make an actual total amount of fuel injection, determined on the basis of the fuel pressure drop, identical to a total of a target amount of fuel to be injected.

Abstract: A fuel specifying apparatus is provided for allowing a person adding fuel to the fuel tank of a vehicle to specify to the vehicle's engine control computer the composition of the fuel being added. The engine control computer uses this information to calculate the average fuel composition in the fuel tank following refueling. In addition, means for reminding the refueling person to specify to the engine control computer the composition of the fuel to be added before adding the fuel to the fuel tank are also provided.

Abstract: An air-fuel ratio control system for an internal combustion engine using an alcohol blended fuel, in which an alcohol concentration-dependent correction coefficient for use in calculating an amount of fuel supplied to the engine is calcuated in response to concentration of alcohol in the fuel defected by an alcohol concentration sensor. An average value of the correction coefficient is calcuated depending on operating conditions of the engine. The amount of fuel supplied to the engine is calculated by the use of the average value of the correction coefficient to thereby control the air-fuel ratio of an air-fuel mixture supplied to the engine.

Abstract: The invention is directed to an intake apparatus for an internal combustion engine with the apparatus including an intake pipe defining a longitudinal axis and a throttle flap mounted on the intake pipe, the throttle flap including a shaft having a shaft radius (r), a throttle flap having a thickness (t) and being mounted on the shaft to be rotatable through a displacement angle, and the shaft having a diameter (2r) greater than the thickness (t); a potentiometer operatively connected to the throttle flap for detecting the displacement angle thereof; a full-load stop for fixing the displacement angle of the flap at full load; the throttle flap being adjusted to a stop angle AW of the throttle flap by impacting on the full-load stop pursuant to the relationship:(2) (KETW)+(2) (AETW).congruent.

Abstract: A fuel blending ratio detecting method computes a control blending ratio on the basis of blending ratio information generated from a blending ratio sensor or air/fuel ratio information generated from an O.sub.2 sensor, and when the engine is stopped, the control blending ratio detected at that time is stored in a backup memory as a memory blending ratio. At the time of re-starting the engine, the memory blending ratio can be used as the control blending ratio B for a predetermined limited period.

Abstract: A fuel injection system for an internal combustion engine including a fuel injector that has an electric solenoid for its actuation that is powered by a battery. In the even the battery condition becomes depleted, the actuating pulse for the solenoid is advanced and extended in duration to accommodate the weakened state of the battery and maintain stable amount of fuel injection regardless of battery condition.

Abstract: Air/fuel ratio of an internal combustion engine is controlled by predicting the air charge to enter the engine two cylinder events into the future and then determining the amount of fuel to be injected to achieve a desired air/fuel ratio. A first fuel pulse is injected, and if needed, a second fuel pulse is injected to achieve the needed amount of fuel for the desired air/fuel ratio.

Abstract: A process and apparatus for utilization of fuels with alcohol additives for an internal combustion engine which are characterized by the fact that at the present time comercial types of fuel have approximately the same molecular weights, which are clearly distinct from the molecular weights of methanol and ethanol. By complete vaporization of a sample volume of fuel, depending on the admixture of alcohol to standard fuel, different volumes of vaporized fuel samples are produced, or different pressures are obtained if the volume is constant. Based thereon and on the sample temperature a correction signal is formed which is characterized by the alcohol and its content in the sample (as compared with reference values stored in a control device), and the correction signal can be utilized to regulate the engine control variables.

Abstract: An engine load parameter-calculating system for an internal combustion engine calculates an engine load parameter indicative of an amount of intake air drawn into the engine. The system determines a value of an opening area formed by a throttle valve and reflecting an amount of intake air, a reference value of the opening area in accordance with the rotational speed of the engine, and a value of the engine load parameter from the value of the opening area and the reference value of same. An engine control system calculates a basic control amount for controlling the engine by the use of the value of the engine load parameter.

Abstract: A fuel tank vapor control system is provided with an improved device for warning of malfunction of a canister. The device judges on malfunction of the canister on the basis of whether opening of a purge passage is effective for causing an inside temperature fall of the canister. In order to prevent an erroneous judgement on malfunction of the canister on the basis of an overflow condition of the canister, a purge passage is first closed so that the canister fully adsorbs hydrocarbon vapors from a fuel tank and then opened so that an inside temperature fall of the canister occurs. Opening and closing of the purge passage is repeated for several times so that a reliable judgement on malfunction of the canister is formed after lapse of a certain time and under a different operating condition of the canister.

Abstract: A system is disclosed for controlling the pressure in a pressurized air supply for an internal combustion engine having pneumatic direct fuel injection, wherein pressurized air from the supply is utilized to inject fuel held within a fuel injector directly into an engine cylinder, against opposing cylinder compression pressure, while the injector is opened during a cylinder injection period in the engine cycle. The system adjusts the duration of the cylinder fuel injection period in accordance with the sensed pressure in the air supply to maintain the air supply pressure above cylinder compression pressure during the injection period, thereby preventing the backflow of fuel through the cylinder fuel injector into the air supply.

Abstract: A method and apparatus for determining the percentage of two different fluids having substantially different dielectric properties such as a gasoline/alcohol or a water/oil mixture. An inductive coil element immersed in the mixture exhibits a distributed capacitance level which is directly proportional to the dielectric constant of the fluid mixture surrounding the coil which, in turn, is directly proportional to the percentage of each fluid in the mixture. The loops of wire in the coil act as equivalent electrodes in creating a capacitance between each loop. The dielectric constant of a mixture will increase with the percentage of the higher dielectric fluid thus increasing the capacitance. An amplifier is constructed that oscillates at the resonant frequency of the LC circuit formed by the coil in the mixture. The resonant frequency decreases as capacitance increases.

Abstract: An air/fuel mixture ratio learning control system for an internal combustion engine using a mixed fuel employs a learnt correction coefficient which is used both in a FEEDBACK mode air/fuel ratio control and in an OPEN LOOP mode air/fuel ratio control. The learnt correction coefficient is derived based on a FEEDBACK air/fuel ratio dependent correction coefficient per one of preselected engine driving ranges and per one of preselected concentration ranges of one fuel component contained in the mixed fuel. The learnt correction coefficient is cyclically derived in a preselected stable engine driving condition during the FEEDBACK mode air/fuel ratio control for updating a previously derived and stored one to minimize a deviation of the FEEDBACK correction coefficient from a reference value.

Abstract: An apparatus for detecting combustion in an internal combustion engine which comprises: a plurality of cylinders wherein an ignition control is performed being synchronized with a revolution number of the internal combustion engine; and an ionic current detector installed at an ignition plug of at least one cylinder of the plurality of cylinders; said ionic currrent detector including means for generating a voltage which corresponds to a level of an ionic current generated by the ignition plug, means for generating a threshold value which is a combustion determining standard, and a comparator which generates an output signal that shows a combustion state, by comparing the voltage with the threshold value; said means for generating a threshold value is composed of a threshold level variable circuit which generates a threshold value corresponding to a running condition of the engine.

Abstract: A fuel injection control system for a two cycle crankcase compression internal combustion engine that employs two sensors for sensing engine load. One of the sensor, a throttle valve position sensor, is more sensitive at low speed and low load conditions and the other of the sensor, a crankcase pressure sensor, is more sensitive under high speed and high load conditions. The output of the fuel injectors is controlled by a map ratio showing the input signals from the two sensors in response to their areas of greatest selectivity.

Abstract: In an engine using various kinds of fuels, the nature of the fuel to be supplied to the engine is detected, and based on this detection result, a theoretical air-fuel ratio is found. Then, using it as a target air-fuel ratio, the amount of supply of the fuel is controlled, and therefore even when the nature of the fuel is changed, an accurate air-fuel ratio control can be made.

Abstract: A fuel injection pump for internal combustion engines has a pump and distributor plunger (21) actuated by a cam plate (12) performing a rotary lifting movement. The cam plate (12) is coupled to the drive shaft for joint rotation therewith. The cam plate has face cams (14) thereon engaging rollers (16) guided in a substantially stationary roller ring (17). For the purpose of detecting the speed and the radial position of the drive shaft (11), a radial position transmitter is provided which has a transmitter wheel (36) firmly connected in the direction of rotation with the drive shaft (11) and which has a detector (37) scanning the transmitter wheel (36) and fixed in the roller ring (17). The roller ring is held on the drive shaft (11) by a ball bearing (41). Thereby uncontrolled relative movements between detector (37) and transmitter wheel (36) are eliminated, and the angular rotational position as well as the speed of the drive shaft (11) can be detected with a high degree of accuracy.

Abstract: A fuel supply system including an evaporated fuel gas purge system measuring a purge gas quantity in purging which comprises: evaporated fuel gas adsorption means having at least a suction port, an exhaust port, a purge port, a chamber in which an adsorption agent that adsorbs an evaporated fuel gas is filled, and detecting means for detecting a quantity of adsorption by the adsorption agent; purge means for purging an adsorbed gas; pressure detecting means for detecting a pressure at a purge gas exhaust part; and suction air temperature detecting means for detecting a temperature of suction air which flows in purging the adsorbed gas. By using the measured value of the purge gas quantity, a fuel injection quantity is corrected, which is determined by an air quantity for suction of the engine corresponding with the purge gas quantity.

Abstract: An engine control apparatus has an intake air quantity detector which detects an intake air quantity to an engine, a controller which controls the engine in response to the output of the intake air quantity detector a load detecting detector which detects a load to the engine, and a clip device the output of the intake air quantity detecting means at a second value when a first time has passed after the load of engine has reached a predetermined value or higher.

Abstract: This invention relates to a fuel injection apparatus for an internal combustion engine, and more particularly to an improved control arrangement for a fuel injection arrangement. In accordance with the invention, an arrangement is disclosed for determining the mass of air taken into the engine crankcase chamber by calculating an average intake air mass which is based not on pressure measurements taken upon each crankshaft rotation individually, but on the arithmetical mean of such pressure measurements taken during a plurality of crankshaft rotations. Thus, a fuel injection control system is achieved which senses differences in crankcase pressure and which eliminates the effects of abnormal changes in crankcase pressure due to effects other than the amount of air inducted.

Abstract: The fuel supply system of an internal combustion engine delivers liquid fuel to electrically operated fuel injectors by means of an electric pump whose output pressure is regulated by control electronics which receives as feedback from a pressure sensor connected into a fuel delivery passage serving the injectors a signal representing the pressure differential between manifold absolute pressure (MAP) and absolute pumped fuel pressure. The pressure sensor has a movable wall that divides its interior into an intake manifold pressure sensing chamber space communicated to the engine intake manifold and a fuel pressure sensing chamber space communicated to the fuel delivery line to the injectors. A magnet is mounted on a central region of the movable wall to transmit a signal to a Hall-effect sensor mounted within the intake manifold pressure sensing chamber space. The feedback pressure signal is derived from the Hall-effect sensor sensing the position of the magnet, and hence that of the movable wall.

Abstract: A number of embodiments of mounting arrangements for the pressure sensor of a control for the fuel injection system of a two cycle crankcase compression internal combustion engine. The pressure sensor is mounted in such a way as to avoid the likelihood of the pressure signal being deteriorated due to fuel and lubricant accumulation and deterioration thereon. In some embodiments, this is done by an insulated mouting and in others this is done by positioning the pressure sensor in a scavenge passage to the engine. In the scavenge passage mounting arrangements, insulation is also employed.

Abstract: A method for regulating the mixture or fuel quantity fed to the cylinders of an internal combustion engine uses an arrangement for the variable metering of the mixture or fuel quantity to the cylinders of the internal combustion engine, a device for acquiring the actual value of the mixture or fuel quantity fed in, by means of measuring the stroke of a valve device, arranged movably in the metering arrangement, and an arrangement for regulating the valve movement. In order to be able to determine the actual value of the metered quantity with great accuracy where simple and cheap sensors are used, the stroke duration of the valve device allocated to each cylinder is determined with a position sensor and regulated to an identical value for all of the valve devices.

Abstract: An engine misfire detector comprises an opto-electric sensor for monitoring light produced by combustion inside a cylinder. The sensor is connected to a variable gain amplifier having a gain control circuit for controlling the amplifier gain. The output of the gain control circuit is compared with a threshold in a comparator to provide a misfire detection signal. The transfer function of the gain control circuit includes an integral term.

Abstract: An electronic control fuel injection device for an internal combustion engine having an inner cylinder pressure sensor for detecting a pressure of a combustion chamber of the internal combustion engine; a crank angle sensor for detecting a crank angle; a device for synthesizing the detected inner cylinder pressure by predetermined crank angles; a device for calculating an intake air quantity based on an engine revolution number which is obtained from the synthesized inner cylinder pressure and the crank angle; a device for synthesizing the calculated intake air quantity in predetermined cycles; and a device for calculating a fuel injection quantity based on the synthesized intake air quantity.

Abstract: A device is provided for improving the measuring accuracy of a process for determining the alcohol content and/or the calorific value of fuels by measuring the electrically measurable qualities of fuel. At least one component of the fuel system of an engine is used with a counterelectrode for the capacitive dielectric measurement of the fuel. At the same time, it is suitable to also use a component of the fuel system with respect to a counterelectrode for the measurement of the conductivity of the fuel. The same counterelectrode can be used for the dielectric measurement and for the measurement of conductivity of the fuel.

Abstract: In one aspect of the present invention, fuel is injected through the injector into the internal combustion engine in non-synchronism with a predetermined crank angle or a predetermined ignition timing each time when the intake air pipe pressure traverses a predetermined set value from the smaller value side to the larger value side. In another aspect of the present invention, the fuel injection is effected in non-synchronism with the predetermined crank angle or the predetermined ignition timing when the intake air pipe pressure traverses a second predetermined value which is selected among a plurality of predetermined set values (the second predetermined value being larger in the absolute value than a first set value, and being close to the first set value) in a case that a time of traversing the first and second set values of the intake air pipe pressure is shorter than a predetermined time.

Abstract: An apparatus for regulating fuel supply according to fuel mixture ratio comprising a light source (5) for radiating a light beam (7) through fuel (3), a light path defining unit (26) for defining a light path for the light beam (7) in accordance with a refraction ratio of the fuel, and a light receiver (24) for receiving the light beam passed through the fuel. The light receiver (24) has connected thereto an actuator (32,43,47) for moving at least one of the light source (5), the light path defining unit (26) and the light receiver (24) by an amount sufficient to keep the light beam (7) always impinging at a constant position on the light receiver (24). The actuator (47) is connectable to a fuel regulator (46,48) for adjusting the fuel supply to an engine in accordance with the amount of the movement of the above components.

Abstract: An air-fuel mixture supply apparatus for a internal combustion engine in which the quantity of air sucked into each cylinder is measured and fuel of the quantity proportional to the measured air quantity is supplied into the measured air flow to thereby control the concentration of the air-fuel mixture exactly.

Abstract: A fuel injection control apparatus for an internal combustion engine in which the air taken into the intake manifold by a Karman vortex detector. However, the amount of fuel injected is based on a calculated intake volume. The calculated intake volume for a time interval is a weighted sum of the measured volume and the calculated intake volume of the previous period. This overaging amounts for surge storage in the intake manifold and other input paths.

Abstract: Apparatus and method for compensating fuel delivery to the cylinders of internal combustion engines for the barometric pressure; for the intake air temperature; and for the heat transferred from the internal engine surfaces to the intake air prior to the air being confined within the cylinder. In the apparatus, temperature sensors are placed to measure internal engine surfaces. The method and apparatus can be used with both a four-stroke or two-stroke engine. In a two-stroke engine, the sensor would be mounted on the crankcase; in a four-stroke, on the intake manifold.

Abstract: An internal combustion engine is provided having a luminosity detector and an arrangement for adjusting the parameters of the engine in response to sensed combustion conditions within the combustion chamber based on particular gain independent parameters of the luminosity signal. The gain independent luminosity parameters can also be used to obtain uniform combustion conditions from cycle to cycle in a given combustion chamber and uniform combustion in the combustion chambers of multi chamber engine.

Abstract: An engine speed control apparatus including an air control valve which controls the cross-sectional area of a bypass passage provided so as to bypass the throttle valve of the engine. The apparatus also includes a control unit which controls a degree of opening of the air control valve on the basis of a synthesized quantity which is obtained by synthesizing a basic air quantity for maintaining a target engine speed and an engine speed feed-back correction quantity which effects to eliminate an error between the target speed and an actual engine speed. An atmosphere pressure sensor is used to detect an atmospheric pressure, and a correction circuit is used to ensure that the synthesized quantity corresponds with the detected atmospheric pressure the engine is started.

Abstract: There is provided an air-flow ratio control apparatus for an internal combustion engine, which comprises a means for measuring a flow amount of intake air, a means for assuming an amount of intake air filled in a surge tank, and means for assuming an amount of exhaust gas remaining in a combustion chamber, and controls a feed amount of fuel based on the result of an assumption effected by these means. Therefore, according to the present invention, an amount of intake air supplied into each cylinder can be precisely measured, an air-flow ratio can be kept constant even in a transient state such as in acceleration or deceleration, and NOx, CO and HC contained in exhaust gas can be reduced. Further, with this arrangement, the size of a conventional ternary catalyst can be reduced.