Abstract: A combination of an apparatus (22) and an engine (30) to provide power to the apparatus, a vehicle (10) of the type having a hydraulic system for operating digging, excavating, or shovelling tools (16,21) for examples, the hydraulic system being pressurized by a pump (33) which is driven from the engine (30) of the vehicle, there being a fuel delivery system for providing fuel to the engine, and a sensing means (49) to sense operation of the apparatus, the fuel delivery system comprising means (48) responsive to the sensing means (49) to provide a first quantity of fuel to the engine (50) when the apparatus (22) is being operated, and to provide a second, reduced, quantity of fuel to the engine (30) when the apparatus has not been operative for a predetermined delay time.

Abstract: An assist air supply system employs a pressurized air source which is formed separately from an induction system of an automotive internal combustion engine. The pressurized air source is connected to an induction system in the vicinity of a fuel injection valve so as to inject pressurized air in the vicinity of fuel injected through the fuel injection valve. A valve means is disposed between the pressurized air source and discharge of a pressurized air passage, so that the pressurized air can be injected or discharged in synchronism with injection timing of the fuel injection valve.

Abstract: A stalling preventing appartus for an engine comprising intake air amount increasing means for increasing the amount of intake air to the engine from idling condition when the vehicle is in a start preparation condition, and rotation speed increase prevention means for preventing the engine speed from increasing due to the increase in intake air amount by the intake air amount increasing means, operation of the intake air amount increasing means and the rotation speed increase prevention means being stopped when the vehicle is in a start preparation condition, whereby a sufficient amount of air is supplied to the engine at starting of the vehicle and a delay in response of the air intake system to the pressing-down operation of the acceleration pedal is eliminated to increase the output torque of the engine at clutch-on and prevent engine stalling.

Abstract: Disclosed is a method for controlling the quantity of intake air supplied to an internal combustion engine, in which the position of a valve member of a flow control valve having a non-linear valve opening characteristic is converted into an intake air quantity or a virtual valve position proportional to the intake air quantity so as to linearize the non-linear valve opening characteristic of the flow control valve. Application of the method of the present invention to an idle speed control device in an engine equipped with an electronic controlled fuel injection system is advantageous in that the quantity of intake air supplied to the engine can be accurately controlled under various operating conditions of the engine, therely preventing rotation of the engine at an excessively high speed and stalling of the engine, improving the fuel consumption and reducing noise generated from the engine.

Abstract: The regulator of this invention is used specifically to regulate the idling speed of an internal combustion engine and includes a servomotor, a throttle unit and a holder designed as separate units and are intended to be combined in an appropriate manner for a particular application. Thus, the throttle unit is provided with a throttle housing incorporating in a cylindrical housing part, a turning space for a throttle member which is connected to a flow channel via an inlet opening and an outlet opening. The flow channel is, for example, built into a wall of an air intake pipe of an internal combustion engine and intersects a receiving opening of this air intake line serving as the holder. The throttle unit is insertable in the receiving opening and is used to control the magnitude of the airflow.

Abstract: An idle speed control apparatus of an engine, having a valve for changing an intake air quality to the engine, a device for measuring an engine coolant temperature, a circuit for detecting an engine speed, and a device responsive to said engine speed for controlling an opening degree of said valve to maintain said engine speed to a predetermined speed under idling state, comprising: a device for producing a signal when said engine coolant temperature exceeds a predetermined temperature; a device responsive to said signal for starting to count a cumulative time period; a device responsive to said cumulative time period for setting a correction opening degree; and a device responsive to said correction opening degree and a current opening degree of said valve means for calculating a learnt opening degree.

Abstract: An electromagnetic valve assembly is shown having an armature and armature-actuated valve member the mass of which is substantially less than the armature and which is not fixedly connected to the armature; upon electrical energization the armature first overcomes a restraining force and then travels a major part of its stroke before actuating the valve member, at a relatively high speed, thereby causing movement of the valve member by kinetic energy of the armature.

Abstract: The device for controlling at least one throttle cross-section at least one control orifice in a bypass line, through which operating medium is fed, regulates the idling speed of an internal combustion engine having an electric positioning motor by which, upon excitation, a throttle member is operable against a spring element so that it opens at least one control orifice to a greater or lesser extent. When the positioning motor is not excited, the throttle member is movable by the spring element into a position in which it opens an emergency-running cross-section of a control orifice. When the spring element is inoperative and the positioning motor is excited, the throttle member is movable into a position which opens a safety cross section of the control orifice. Advantageously, the throttle member is provided with a triangular throttle orifice and the single control orifice is parallelogram shaped.

Abstract: An engine air intake valve for controlling engine idling speed includes a rotary electrical actuator for actuating a rotary slidable valve element across a flow port in a cylindrical valve seat. The flow port is rectangular so that each unit angular movement of the valve element produces the same in air flow rate. The rotary electrical actuator includes a stator having a wire wound therearound to produce two opposed magnetic poles at diametrically-spaced points on the stator circumference.

Abstract: An apparatus controls the number of idle rotations of an internal combustion engine for a vehicle so that the number of engine revolutions becomes a target number of idle rotations, the apparatus starting the controlling of the number of idle rotations when each and every one of a plurality of first conditions is satisfied, the first conditions including the opening degree of an air inlet throttle valve of the internal combustion engine, the vehicle speed, and the number of engine revolutions.

Abstract: A self-propelled portable watercraft, including a deck and hull, an engine, and a waterjet propulsion system, capable of operating while a supply of air is unavailable. The air substitute, consisting of a mixture of oxidizing gas and recycled exhaust gas, is delivered to the engine through a self-actuated control valve. In addition, the waterjet propulsion system is equipped with an intake port at the terminus of a narrow, elongated, hollow downward extension of the hull. The purpose of the extension being to minimize the occurrence of a loss of thrust which can result when the craft is vertically displaced above the surface of the surrounding water.

Abstract: An internal combustion engine includes: a combustion chamber with a suction opening; an inlet valve for closing the suction opening; a fluid supply line with an open end; and a gaseous medium supply line with an open end. The open end of the fluid supply line is in close proximity to the suction opening. The gaseous medium supply line surrounds a portion of the fluid supply line in the vicinity of the open end of the fluid supply line. The open end of the gaseous medium supply line is in close proximity to the open end of the fluid supply line. And the open end of the gaseous medium supply line is directed toward the suction opening of the combustion chamber. In operation, fluid is supplied through the fluid supply line in such small quantities that the fluid is in an almost pressure-free condition at the open end of the fluid supply line.

Abstract: The invention is directed to a bypass throttle control for a motor vehicle. A cross section of a critical opening of the bypass throttle control past which a marginal edge of a throttle valve moves during its opening motion is designed such that no limiting edge of the opening that extends parallel to its marginal edge is present below an intermediate position of the throttle valve. As a result thereof, whistling noises that otherwise occur in integrated bypass throttle controls and an undesired deformation of a control characteristic curve are prevented.

Abstract: A device for controlling a throttle cross-section of at least one control orifice in a bypass line extending around a throttle valve of an air intake pipe of an internal combustion engine, for regulating an idle speed of the internal combustion engine, and comprising a throttle member, a spring element for biasing the throttle member to an initial position thereof, and a positioning motor for moving the throttle member from its initial position against a bias force of the spring element, upon failure of the spring element and when the positioning motor is actuated, to establish a safety cross-section in the bypass line, a quantity of operating medium flowing through the safety cross-section being less than a quantity of operating medium flowing through a complete cross-section of the control orifice whereby idle operation of the internal combustion engine is insured.

Abstract: A method and apparatus for maintaining the optimum oxygen level in a power plant, such as, an internal combustion engine comprises a combination of a pollutant sensor associated with the exhaust of the engine to generate electrical signals proportional to the level of pollutants in the exhaust stream, a supplementary oxygen source and a flow control valve which is responsive to the signal generated by the pollutant sensor to open the valve for flow of oxygen at a flow rate proportional to the electrical signal until the pollutant level is reduced to a predetermined value.

Abstract: The proposed feed device comprises non-return valve means, preferably of flap type, which are able to open and close the small ducts provided for feeding the individual cylinders of an internal combustion engine when the throttle valves are in their maximum closure position.

Abstract: In a fuel/air mixture preparation device for internal combustion engines, there is a nozzle body (2) of rotational symmetry having a throttle member (7) of rotational symmetry which is displaceable within the body, the body forming a convergent/divergent nozzle. With the throttle member (7), which is displaceable in the nozzle body, the main air-mass throughput through the nozzle is determined. At least one fuel feed line (8 and 9) enters into the nozzle body. The fuel feed line has a circumferential fuel slot (10) which is developed in the wall of the nozzle body as well as a circumferential fuel/air slot (12) which joins it and is open towards the inside in the nozzle body. At a transition place between the fuel slot and the fuel/air slot there debouches an air feed (13) which is approximately under ambient air pressure. From a gap opening (11) of the fuel/air slot, the fuel mixed with air is injected approximately transversely to the direction of the main air mass flow, into the inside of the nozzle body.

Abstract: A flow control valve includes a hollow cylinder 32 having an open end and a fluid flow port 31 formed in its circumferential wall, a solenoid coil disposed around the cylinder, and a valve member 41 slidable within the cylinder in response to an amount of power supplied to the solenoid coil for adjusting an opening area of the fluid flow port to control the flow rate of the fluid flowing through the fluid flow port and the open end of the cylinder. A protective inner-diameter portion 32a formed in the open end of the cylinder is provided in association with a fluid flow path including the fluid flow port and the open end of the cylinder for preventing any foreign matters entrained in a fluid from being caught in the clearance defined between the hollow cylinder and the valve member by providing an annular clearance between the cylinder and the valve member.

Abstract: A method for controlling the air-fuel ratio in internal combustion engines, in which a low and/or decelerating engine speed is detected according to a change speed of engine operation parameters and the degree of opening of a flow regulating valve is controlled according to such change speed when deceleration is detected.

Abstract: An apparatus for assisting in governing the idling rpm of an internal engine including a bypass line that bypasses a throttle valve in an air intake tube. A rotary slide valve secured to one end of a shaft which is controlled by a motor is rotatable in the bypass line to adjust air flow through the bypass line. The bypass line is integral with a lid-shaped housing part in which roller bearings juxtaposed the rotary slide valve is secured. The upper end of the shaft is rotatable in bearings carried by an upper housing part. The housing parts are secured together in axial alignment with each other.

Abstract: A device comprising a body in which is formed a chamber in which fuel is mixed with air; a cylindrical mixture delivery duct the opening of which is controlled by a throttle valve; and a body cover to which is fitted a fuel injector for supplying atomized fuel into the mixing chamber; the aforementioned mixing chamber comprising at least a first and second portion defined by differently tapered surfaces, and a third portion defined by a cylindrical surface equal in diameter to the aforementioned cylindrical mixture delivery duct; the axial length of the cylinderical surface of the third portion of the mixing chamber, measured between the axis of the throttle valve and the top edge of the third portion itself, being at least equal to the radius of the circular contour of the aforementioned throttle valve.

Abstract: A control method for the idling speed of an engine, in which method, from the engine speed at the time when transition toward the idling state is determined by the switching, for example, of an idling switch to "ON", the correction quantity of the control value of valve means for regulating the intake air quantity of the engine is set, a drop in the engine speed being avoided, and at the same time, in the convergence toward a learned value thereafter, convergence to the learned value of the valve means at a variation rate corresponding to the engine speed is made possible, whereby rapid correspondence toward feedback control is realized.

Abstract: A valve control system of an internal combustion engine has a control circuit comprising valve control quantity setting means for setting the control quantity of valve means installed in the engine in accordance with the operational state of the engine and generating a first actuation signal in accordance with said control quantity and actuating means for actuating said valve means in accordance with said first actuation signal, in which said control circuit comprises: clock oscillation means for generating a check signal shorter than the reaction time of said valve means; synthesizing means for synthesizing said check signal and said first actuation signal and generating a synthesized signal; actuating means converting said synthesized signal into a second actuation signal and a valve actuation state determination signal as outputs, which are transmitted to said valve means; and valve actuation state decision means formed for detecting said valve actuation state determination signal and deciding the actuatio

Abstract: A flow rate control system for controlling the idling rpm of an engine of a vehicle to a predetermined level in accordance with the temperature of cooling water or outdoor air, so as to eliminate hunting occurring in the flow rate of air supplied to the engine at engine startup the system includes a first valve seat, adapted to come into and out of engagement with a first valve body of a flow rate control valve assembly, and an annular protrusion located on a portion of an inner peripheral surface on an inlet side of the first valve seat. A conical surface portion is located downstream of the annular protrusion on an outlet side of the inner peripheral surface and divergingly tapers in a direction toward a downstream side of the first valve seat.

Abstract: A system for measuring intake air amount to be introduced into an engine cylinder employs a throttle angle sensor as a basic intake air flow amount indicative factor. Basic intake air flow amount is derived on the basis of a throttle valve angular position and an engine speed. The basic intake air flow amount is corrected with taking delay factor to introduce the intake air past the throttle valve into the engine cylinder, and a temperature dependent factor compensating variation of air density depending upon the temperature condition.

Abstract: A self-diagnosis system for an auxiliary air control system of an internal combustion engine having an auxiliary air control valve provided in an auxiliary air passage bypassing a main throttle valve, comprises an air flow meter for detecting the amount of intake air, a control unit diagnosing malfunction of the air flow meter and comparing the amount of air inducted when the main throttle valve is fully closed with a value calculated according to the opening angle of the auxiliary air intake control valve. The control unit deems that the auxiliary air control system has malfunctioned only when the amount of intake air is larger than the calculated valve. In the device according to the invention, the malfunction of auxiliary air control system can be detected within a relatively short time, such as 1 sec, and the malfunction can be detected regardless of the engine speed.

Abstract: A method and apparatus is provided for controlling the solenoid current of a solenoid valve which controls the amount of suction air in an internal combustion engine. A solenoid current control value is calculated as a function of engine operating conditions and a corrected solenoid current control value is determined as a predetermined function of the solenoid current control value. The solenoid valve is controlled as a function of the corrected solenoid current control value. The solenoid valve is controlled by generating a pulse signal having a duty ratio which is a function of the solenoid current control value.

Abstract: The present invention is an idle bypass system including a throttle body having a longitudinal axis with a throttle plate disposed transversely to the longitudinal axis. The throttle body includes a secondary passageway having an inlet and an outlet to allow fluid flow to bypass the throttle plate when in a closed position. A motor is secured to the throttle body and cooperates with the secondary passageway for allowing a predetermined amount of fluid flow through the outlet. A solenoid-actuated valve is secured to the throttle body and cooperates with the secondary passageway for allowing a predetermined amount of fluid flow to the intake manifold when the amount of fluid flow past the motor is not within predetermined limits.

Abstract: The present invention is an idle fluid flow shutoff assembly including a throttle body having a longitudinal axis with a throttle plate disposed transversely to the longitudinal axis. The throttle body includes a secondary passageway having an inlet and an outlet to allow fluid flow to bypass the throttle plate when in a closed position. A motor is secured to the throttle body and cooperates with the secondary passageway for allowing a predetermined amount of fluid flow through the outlet. A pressure-actuated valve is moveable in response to the absence and presence of a predetermined pressure level and cooperates with the secondary passageway for allowing a predetermined amount of fluid flow to the intake manifold when the amount of fluid flow past the motor is not within predetermined limits.

Abstract: A fuel control system for providing a dashpot operation at release of an accelerator pedal of a motor vehicle. A bypass is provided around a throttle valve of an engine and an idle speed control valve is provided in the bypass, for controlling air passing in the bypass. When the accelerator pedal of the motor vehicle is released, an idle signal is produced. In response to the idle signal, idle speed control valve is gradually closed. After a set time, fuel supply by a fuel injector is cut off.

Abstract: An auxiliary air control valve for an engine, comprising a valve casing which has an air inlet port and an air outlet port, and a valve seat having a valve port of prescribed diameter; a valve element which is disposed in the face of the valve seat to control the cross-sectional area of the internal air passage and has a movably tapered portion fitted in the valve port to control the cross-sectional area of the internal air passage depending on the positional relation between the valve element and the valve seat, and a cylindrical portion provided next to the maximum-diameter part of the tapered portion and moved in the valve port to make the cross-sectional area of the internal air passage minimum and allow an actuator to be moved to an extreme position while the cross-sectional area is kept minimum; a spring which urges the valve element in such a direction as to open the valve; and the actuator for moving the valve element against the force of the spring, depending on at least one operational parameter of

Abstract: An arrangement for regulating the combustion air mixture in the case of a gas engine operating on a lean fuel, and in the induction line of which there is an air-gas mixer, a lambda regulator being provided and following which there is, for varying the combustion air proportions, a positioning device which adjusts the air-gas mixer, and also an output measuring device for ascertaining the engine output. A manometer determines the actual value of the mixture pressure upstream of the inlet valves of the engine, linked with the value for the combustion air proportions. By adjusting the combustion air proportions, it is possible to regulate the mixture pressure to the output dependent desired value for the mixture pressure as ascertained in a device within the lambda regulator.

Abstract: A system for automatic control of the fuel mixture strength supplied in slow-running conditions to a heat engine having a fuel injection system and means for supplying supplementary air in adjustable quantities, comprising first means for periodically varying the quantity of supplementary air supplied to the engine and for detecting the consequent variation in the slow running of the engine for the purpose of obtaining activation for second means for modification of the quantity of fuel supplied to the injectors of the system for compensating the variation in the strength of the mixture.

Abstract: A variable air induction control system for an internal combustion engine. The engine intake passage is divided into a long and small diameter main passage and a short and large diameter auxiliary passage. The auxiliary passage is provided with a valve which is opened and closed to adjust the air flow rate. The system is arranged such that, in accordance with the cylinder pressure, the intake air passes through the main intake passage during low speed engine operation and through both the main and auxiliary passages during high speed engine operation, whereby the air induction efficiency (charging efficiency) is enhanced and the engine output increased. As knocking is more likely to occur when the air induction efficiency is high, the opening/closing of the valve is controlled depending on whether or not knocking occurs. Moreover, it may be arranged such that when knocking does occur, it is first coped with by retarding the ignition and if knocking cannot be eliminated in this way, the air intake is adjusted.

Abstract: A method and apparatus for metering fuel to an engine wherein a continuous supply of fuel is provided by a pump (14) to a fixed capacity chamber (11) and gas under pressure is admitted periodically to said chamber to maintain in the chamber a pressure not greater than the fuel pressure, so that fuel will flow into the chamber as long as there is a pressure differential between the gas in the chamber and the fuel supply. A delivery port (20) in said chamber is open for substantially the duration of the period that gas is admitted to the chamber so that the fuel in the chamber at the time of admission of gas thereto, and fuel entering the chamber during the period of admission of gas, is delivered from the delivery port (20) to the engine. The pressure differential between the fuel supply and the gas in the chamber is controlled in accordance with the fuel demand of the engine to control the quantity of fuel delivered each cycle to the engine.

Abstract: An apparatus for controlling the amount of intake air to an engine comprises a throttle body, a throttle valve disposed in the body, a bypass passage that bypasses the throttle valve. The throttle body forms a part of the air intake passage for the engine. In one embodiment of the invention, a guide passage is formed in the throttle body and extends upwardly from the bypass passage. The open end of the guide passage is disposed above the center line of the inside of the throttle body. In another embodiment of the invention, a barrier such as a protrusion or groove is formed in the inner surface of the throttle body and disposed above the open end of the bypass passage to prevent fuel, oil, and other substances from flowing into the bypass passage.

Abstract: A method is provided for the control of nitrogen oxide and carbon monoxide emissions from a digester gas engine by the injection of air immediately upstream of the intake valve to form a gradient charge in the combustion chamber having an incombustible portion adjacent the piston and a more concentrated combustible portion adjacent the spark plug, and by the calibration of the spark advance curve of the engine.

Abstract: A device and method are provided for the pneumatic injection of fuel into an engine. The device comprises at least one auxiliary duct having two ends one of which is connected to an exhaust pipe and the other to an injection member.

Abstract: An air inlet nozzle is mounted in a valve pocket above the intake valve of a combustion chamber to allow high speed airflow to mix with fuel in the pocket and enter the combustion chamber to create desired air swirl. Airflow through the nozzle is varied by a computer operated solenoid.

Abstract: Described herein is a method for controlling the bypass air flow of internal combustion engine, which prevents the air-fuel ratio from becoming over rich temporarily in the initial stage of deceleration of the engine by driving a control valve to open a throttle by-pass passage on deceleration of the engine to supply auxiliary air thereto and which includes: detecting the open angle of the throttle valve; setting a valve opening rate according to the throttle open angle; setting an upper limit on the valve opening rate when it is greater than an upper limit value determined in relation with the engine speed; driving the control valve according to the valve opening rate; and on deceleration of the engine, gradually reducing a valve opening rate set in an operation prior to the deceleration.

Abstract: An apparatus is proposed for regulating the idling charge of an internal combustion engine having at least two banks each including a plurality of engine cylinders. Each bank has its own air intake line with throttle valves. Bypassing each throttle valve is a bypass line, in which a throttle opening is openable, each by a respective rotating slide, in accordance with engine operating characteristics by means of a common control motor via a common pivot shaft.

Abstract: An auxiliary air amount control device for an internal-combustion engine, which for the purpose of permitting uninterrupted control of the number of revolutions of the engine mainly during an idling operation of the engine, enables an auxiliary air amount control valve disposed in a bypass interconnecting the upstream and downstream sides of a throttle valve to be so controlled that the idling operation will be carried out properly even when an arithmetic device serving to set the opening degree or the position of the control valve is out of order. This is effected by feeding a prescribed command value to an air control valve of the solenoid type when the arithmetic device is out of order, and by varying the resistance of the valve solenoid coil as a function of engine temperature, so that the opening degree of the valve is jointly responsive to the fixed command and the engine temperature.

Abstract: A carburator for internal combustion engines has a main jet for delivering fuel to be entrained with air as it passes through the carburator to the inlet side of the engine. A throttle valve is disposed downstream of the main jet for controlling the flow of air and entrained fuel. An idling jet disposed downstream of the throttle valve is adapted to deliver fuel to the air stream at a rate sufficient to ensure that the engine continues running while the throttle valve is substantially closed. The idling jet is additionally adaptable to admit air to the stream of air-fuel mixture as it flows through the carburator at higher rates of air flow. Means are provided to switch the idling jet between fuel delivering and air delivering modes in response to engine speed. Thus, at lower engine speeds fuel is delivered through the idling jet and a slightly rich mixture passes to the engine. At higher speeds, air is admitted resulting in a weaker mixture than has been set by the main jet and the throttle valve.

Abstract: Apparatus for the continuous injection of fuel into the intake piping of an internal combustion engine comprises an air pump for delivering an air stream portion deviated from the engine intake pipe, a fuel pump for delivering fuel from a source, a metering device controlled in response to operating conditions of the internal combustion engine and receiving fuel delivered by said fuel pump and the air stream portion delivered by said air pump for mixing said fuel and air stream portion and delivering the same to the intake piping of the engine, in which the supply of said air stream portion to the metering device is interrupted during an operating condition of the engine, preferably a coasting condition of operation of the engine. Interruption of the air stream portion may be effected by a shut-off valve in the conduit delivering the air stream portion from the air pump, responsive to a coasting condition of the engie.

Abstract: A method and apparatus are provided for controlling the solenoid current of a solenoid valve which controls the amount of suction air in an internal combustion engine. The actual solenoid current flowing through the solenoid is detected and a solenoid current control valve is calculated as a function of engine operating conditions. A corrected solenoid current control value is determined as a function of the solenoid current control value and a pulse duration signal is determined as a function of the corrected solenoid current control value. A feedback control term is calculated as a function of the actual solenoid current and the corrected solenoid current control value. Further, a temperature corresponding to the solenoid temperature is detected and a temperature correction value is generated corresponding thereto.

Abstract: An electronic control device for an internal combustion engine provides feedback control of the idle speed using as a reference value an intake air flow rate set in correspondence with the reference value of the idle speed.

Abstract: An apparatus for controlling the air-fuel ratio for an internal combustion engine and which includes a flame sensor provided in the vicinity of a spark plug within an engine combustion chamber, an air induction passage for bypassing a throttle valve of a carburetor, an electromagnetic valve disposed in the air induction passage to control an amount of air flowing through the air induction passage, and an electronic control unit actuating the electromagnetic valve by means of input electric signals from the flame sensor and including a control MAP based on a mutual relation between an air-fuel ratio and a time of firing.

Abstract: A bypass is provided around a throttle valve of an engine, and a solenoid operated on-off control valve provided in the bypass so as to control flow of intake air. When the engine is accelerated in the coasting of a vehicle, an acceleration signal is produced. In response to the acceleration signal, a driving pulse train is fed to the control valve so as to reduce the intake air flow in dependence on coolant temperature of the engine by the coolant temperature.

Abstract: A method determines a control parameter of an air/fuel ratio of an internal combustion engine having an idle rotational speed control device by which the throttle valve is opened when an electric unit such as the head light or the air conditioner is turned on during the idling of the engine. The air/fuel ratio is controlled to be leaner than a target air fuel ratio when the engine is idling, and controlled to a further leaner side when the electric unit is operating during the idling of the engine.

Abstract: A method of controlling an operating amount of an operation control system for controlling the operation of an internal combustion engine wherein the operating amount is controlled on the basis of first and second desired operating amounts determined in dependence on respective first and second operating parameters indicative of engine load conditions, respectively, when the engine is operating in a predetermined low load condition, and when the engine is operating in another operating condition. When the engine has entered the predetermined low load condition from an operating condition other than the predetermined low load condition, a correction value of the operating amount is obtained on the basis of the difference between the determined first and second desired operating amounts, to correct the determined first desired operating amount. The corrected first desired operating amount is compared with the determined second desired operating amount.