Abstract: In an electronically controlled engine supplying fuel from a fuel injector near an intake port to an intake system, asynchronous acceleration fuel injection is carried out in relation to the secondary differential d.sup.2 X/dt.sup.2 of intake pipe pressure or intake air flow rate with respect to time t. Since the d.sup.2 X/dt.sup.2 increases rapidly and accurately after the start of acceleration of the engine, the asynchronous acceleration fuel injection can be carried out rapidly and accurately.

Abstract: A method and an apparatus for controlling the air-fuel ratio in an internal combustion engine in which the calculation of the presumed amount of fuel attached to the wall of the intake port of the engine is effected for correcting the amount of the fuel supplied to the engine in order to compensate for the variation of the air-fuel ratio of the air-fuel mixture used in the combustion of the engine.

Abstract: A fuel supply control system for an internal combustion engine having a fuel supply cut-off function is equipped with means for increasing in amount, the fuel supply of fuel in response to resumption of the supply of fuel subsequent to the fuel cut-off operation, thereby compensating for a fuel delivery delay characteristic which otherwise would occur upon the resumption of the supply of fuel. The increase in fuel is determined in response to at least one of variables which affect the rate of evaporation of the fuel adhered to the inner wall of the intake manifold during the fuel cut-off operation.

Abstract: The volumetric efficiency of an internal combustion engine is calculated from the detected flow rate of the intake air and from the detected rotational speed. The changing rate of the calculated volumetric efficiency is restricted to a limit rate. Then, the amount of fuel to be injected into the engine is calculated, depending upon the restricted volumetric efficiency.

Abstract: An air/fuel ratio feedback control system adapted to control the air/fuel ratio of an air/fuel mixture being supplied to an internal combustion engine, by the use of a first coefficient having a value variable in response to actual exhaust gas concentration and at least one second coefficient having a value variable in dependence on the kind of a particular operating condition or region in which the engine is operating.

Abstract: A heat-type flow sensor is provided on the upstream side of a Venturi portion formed in an air-intake path and in an air bypass communicating with the Venturi portion. An electromagnetic device is provided to control the amount of air flowing in the air bypass so that the output of the heat-type flow sensor converges to a set level. This electromagnetic device drives a fuel-scaling valve to scale fuel in accordance with the change of the amount of air supplied to the engine, and this scaled fuel is continuously injected into the air-intake path.

Abstract: In internal combustion engines with external ignition the fuel metering is often interrupted during overrun operation for the purpose of saving fuel. It is proposed to inhibit this blocking of the fuel supply in those cases where the danger of slipperiness because of ice or snow exists. This danger is addressed by means of the method of measuring and evaluation of the intake air temperature and/or the temperature in the vicinity of the motor vehicle. Besides the possibility of realizing the invention from the block switch diagram, it is also pointed out that the electronic control device in accordance with the present invention can also be implemented relatively easily within the confines of a computerized control of the fuel metering.

Abstract: In an electronic fuel injecting method and device for an internal combustion engine, wherein a basic injection time is obtained in accordance with an intake pressure of the engine and an engine rotational speed, and, during transition, the basic injection time is corrected in accordance with the operating conditions of the engine so as to determine a fuel injection time, when a change in value of the intake pressure in every first predetermined time period exceeds a first criterion value, an increase correction for acceleration or a decrease correction for deceleration is effected, in case the change in value of the intake pressure in every first predetermined time period does not exceed the first criterion value, if a change in value of the intake pressure in every second predetermined time period being longer than the first predetermined time period exceeds a second criterion value, at least an increase correction for acceleration is effected, and if the change in value of the intake pressure does not excee

Abstract: An electronically controlled fuel injection system including an air flow sensor disposed in the intake pipe of an internal combustion engine upstream of its throttle valve to detect the amount of air flow to the engine and a control unit responsive to the output signal of the air flow sensor to adjust the amount of fuel to be supplied to the engine, is further provided with a fuel enrichment circuit responsive to the output signal of the air flow sensor whereby when the amount of air flow changes in a direction to decrease, a signal commanding an increase in fuel amount which is proportional to the rate of the change is fed to the control unit. The fuel enrichment circuit has an upper limit value such that the increase in fuel amount is prevented from exceeding an amount corresponding to the upper limit value. The fuel enrichment circuit is adapted so that the amount of fuel is not increased when the rate of change of the air flow in the decreasing direction is smaller than a predetermined lower limit value.

Abstract: A system controlling the spark timing for an internal combustion engine having ignition plugs, a fuel supply control system for cutting off the fuel supply to the engine including a fuel supply cutoff delay means is disclosed.According to the present invention, there is provided a system for controlling the spark timing comprising a means for retarding the spark timing from an optimum spark timing whose value is derived on a basis of the engine speed or engine speed and air flow rate per rotation, whereby the shock generated due to abrupt changes in engine torque when the fuel supply cutoff delay means is operated are reduced.

Abstract: In a method for controlling the fuel injection in an internal combustion engine by using an electronic control device for triggering the fuel increase in the engine acceleration state, the fuel increase is prohibited or modified during gear change operations of the automobile driven by the engine corresponding to the detection of the state where the rate of change of the ratio between the intake air amount is algebraically less than a predetermined value, or to the output signal of a clutch switch.

Abstract: A fuel supply cut control device comprising an electronic control unit for controlling the injecting operation of a fuel injector. When the throttle valve is closed to the idling position under an operating state where the engine speed is higher than the cut speed, the fuel injection of the fuel injector is stopped. After this, when the engine speed is reduced below the resume speed, the injecting operation of the fuel injector is started. When the vehicle speed is high, the cut speed and the resume speed are low, and when the vehicle speed is low, the cut speed and the resume speed are high.

Abstract: A deceleration fuel cut device adapted to interrupt the supply of fuel to an internal combustion engine when a detected actual engine rotational speed is higher than a predetermined value, and simultaneously a detected intake pipe pressure is lower than a predetermined value. The predetermined engine speed value is set to lower values as the detected actual engine temperature increases. The predetermined intake pipe pressure value is determined as a function of the detected actual engine speed. The predetermined intake pipe pressure value and/or the predetermined engine speed value may be set at different values between the time of initiation of cutting off the fuel supply and the time of termination of same, to impart a hysteresis characteristic to the fuel cut operation.

Abstract: In an air-fuel ratio control system for an engine, when the engine is driving at a specified operating condition such as an acceleration or deceleration condition, the air-fuel ratio is controlled at a stoichiometric air-fuel ratio. During a steady-state operating condition following the termination of the specified operating condition the air-fuel ratio is gradually changed from the stoichiometric air-fuel ratio to a leaner air-fuel ratio which provides the optimum fuel consumption and the air-fuel ratio for optimum fuel consumption is maintained until the engine again comes to the specified operating condition. The change to the optimum fuel consumption air-fuel ratio takes place immediately after the termination of the specified operating condition or after the expiration of a given time after the termination of the specified operating condition.

Abstract: An electronic ignition and fuel control system is provided for internal combustion automotive vehicle engines which are of the spark ignition type. The ignition and fuel control system of this invention includes an electronic timing and detector circuit, distributor circuit, clock and command circuit, ignition power circuit and air-fuel control circuit. The clock and command circuit responds to selected positioning of an accelerator control element to provide either a plurality of firing pulses to the engine ignitors in an acceleration mode of operation, or to provide single pulse firing in the case of steady state operation or a deceleration mode of operation. In the ignition and power circuit, individual coils are provided for generating a high voltage firing pulse applied to each of the ignitors that are interconnected with the respective coil.

Abstract: A method controls of the amount of fuel, ignition timing and the amount of exhaust reflux recirculation during transient operations of an internal combustion engine such as acceleration and/or deceleration. In this method, the present data of the intake air flow rate or intake negative pressure and previously-derived data with respect thereto are utilized to control the amount of fuel to be injected based on an extrapolation or correction method.

Abstract: A method for controlling an internal combustion engine equipped with a fuel injection valve fitted to its intake manifold. Repeatedly values are determined of a first quantity approximately representing the proper amount of fuel to be injected, at least partly based upon signals from an air flow meter and a revolution sensor. Simultaneously, repeatedly the current value of a second quantity approximately representing the actual amount of fuel to be injected is determined, at least partly based upon signals from the air flow meter and the revolution sensor, an average value of all the successive instances of the value of the first quantity in some time interval up to the present is determined, and the current value of the first quantity is compared with this average.

Abstract: An improvement in an electronically controlled fuel injection apparatus which determines the amount of fuel injection and, in a deceleration mode, stop the fuel injection until an engine rotation speed falls below a predetermined fuel injection reinitiation rotation speed if the current engine rotation speed is higher than a predetermined fuel injection stop rotation speed. When an air conditioner compressor is active, the fuel injection stop rotation speed, or the fuel injection stop rotation speed and the fuel injection reinitiation rotation speed, or the fuel injection reinitiation rotation speed are raised.

Abstract: A method and apparatus for controlling an internal combustion engine having at least one cylinder adapted to intake, during each intake stroke of the cylinder, fuel supplied in a plurality of instalments. Means is provided for controlling the amount of fuel supplied to the engine. Adjustments of the control means are produced by generating electrical signals indicative of engine operating conditions, and, with a digital computer, repetitively calculating values corresponding to settings of the control means. The digital computer is programmed to calculate a basic value from an algebraic function describing a desired relationship between the engine conditions and the basic value, detect engine acceleration and deceleration conditions from changes in the engine conditions, and add a positive or negative value to the calculated basic value when the engine is accelerating or decelerating to correct the calculated basic value for the detected acceleration and deceleration conditions.

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

Abstract: An electronic fuel supply control system for internal combustion engines which carries out the engine fuel cutoff while the engine is decelerated either with a predetermined delay or immediately depending on engine driving conditions, and preferably on the state of the transmission, thus reducing the jolt produced when the fuel cutoff is carried out.

Abstract: An internal combustion engine provided with a system for controlling the predetermined idling rotational speed N.sub.F of the engine, and a system for operating a fuel injector so that the injector is de-energized when the rotational speed is higher than N.sub.cut and the injector is energized when the rotational speed is lower than N.sub.RTN. A value of N.sub.cut is the product of N.sub.F and a predetermined positive value .alpha..sub.1 and the value of N.sub.RTN is the product of N.sub.F and a predetermined positive value .alpha..sub.2 (<.alpha..sub.1).

Abstract: A system for detecting the operation of the throttle valve of an internal combustion engine for an emission control system for internal combustion engines. The emission control system has a three-way catalyst convertor, a detector, such as an oxygen sensor for detecting the concentration of oxygen in the exhaust gases, an on-off type electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture and an electronic controller. The system comprises a transducer, such as a potentiometer and a pair of sample-and-hold circuits, in which each gate thereof is periodically operated by pulse trains for sampling and holding the output voltage of the transducer, which pulse trains have a 180 degrees phase difference with respect to each other. Both sample-and-hold circuits are connected to an operational amplifier type comparator through relay switches.

Abstract: Fuel is cut off in the deceleration of a vehicle to improve efficiency of fuel consumption. Rotational speed of an engine in the resumption of fuel supply in the completion of the fuel cut-off is set to a value smaller than that otherwise set when a brake device is operated or the vehicle speed is higher than a predetermined value. While the torque of the engine varies abruptly to produce impact when the fuel cut-off is completed, passengers have a slight feeling of impact while the vehicle is being braked and travelling with high speed. Thus, while the feeling of impact is reduced, a period of fuel cut-off is increased to improve further the efficiency of fuel consumption and others.

Abstract: A method for controlling an internal combustion engine with a fuel injection valve fitted to its intake manifold. Repeatedly a first quantity representing the desired amount of fuel to be supplied to the combustion chambers in the next fuel injection pulse, a second quantity representing the proportion of fuel in one pulse which will adhere to the walls of the intake system, and a third quantity representing the proportion of fuel adhering to these walls which will be sucked off into the combustion chambers between two successive pulses are determined, based upon sensed values of certain operational parameters.

Abstract: A control apparatus is proposed for a fuel metering system of an internal combustion engine having at least one additively functioning warmup enrichment circuit. The apparatus is characterized in that the additive enrichment can be reduced during overrunning. The purpose of this feature is to maintain the cleanest possible exhaust gas even during the warmup phase during overrunning. This is attained, for instance, by means of a logical linkage of an overrunning recognition signal and the output signal of an additively functioning correction circuit for the metering signal.

Abstract: A digital-analog fuel injection system wherein fuel lean out is controlled by a fuel mapping circuit 36 which provides one of sixteen levels of percent lean out control of the fuel pulse width supplied to an injector. In order to provide an immediate update of the engine demands, a pulse generation circuit 72 operates in real time. The fuel mapping circuit 36 provides corrections to the pulse generating circuit on a sampled update basis. This is accomplished by using a digital word 34 generated by a microprocessor 10 to control a multiplying digital to analog converter whose reference input is an electrical signal (V.sub.MAP) representing the present manifold pressure and an offset voltage (V.sub.O) accounting for the several variable of the system such as the engine, injectors and pressure sensor. The output signal (V.sub.B) from the fuel mapping circuit 34 is then applied to a pulse generating circuit 72 to control the generation of fuel pulse width which is being applied to a fuel injector driver 46 (FIG.

Abstract: Disclosed is a fuel supply control system for controlling fuel amount to be supplied to an internal combustion engine including a sensor means for detecting engine load condition and other control parameters and generating sensor signals, an arithmetic means for determining a basic pulse width of a pulse signal indicative of basic fuel amount to be supplied, a means for correcting the basic pulse width of the pulse signal corresponding to various control parameter respectively indicative of engine conditions such as engine coolant temperature and a means for distinguishing engine driving condition based on inputs one of which is sensor signal indicative of engine load condition and generating correction command indicative of correction coefficient. The correction command is applied to the correction means to effect the same to increase or decrease the pulse width of the pulse signal or shut off the fuel supply to the engine.

Abstract: Arrangement for fuel supply to the combustion chambers of a vehicle internal combustion engine with an engine-braking disconnection. A sensor determines the rotational speed of the engine. Function generators determine the limit value signals which are a function of the rotational speed of the engine. Comparators compare the signals determined by the function generators with a load signal received from a potentiometer acting as a position sensor indicating the position of the intake manifold throttle valve. The comparators are connected to switches which regulate or eliminate the fuel supply to the combustion chamber depending upon the output of the said comparators by supplying fuel to all combustion chambers, to groups of combustion chambers, or to no combustion chambers, so that the operation of the engine is fuel-consumption optimal.

Abstract: A system for controlling air-fuel ratio for a carburetor for an internal combustion engine having an intake passage, on air-fuel mixture supply device, a throttle valve, an exhaust passage, a detector such as an oxygen sensor for detecting the concentration of oxygen in the exhaust gases, an on-off type electromagnetic valve for correcting the air-fuel mixture and an electronic controller.The electronic controller comprises a comparing circuit for comparing the output signal of the detector with a reference, a proportional and integration circuit for producing a control signal connected to the comparing circuit, a triangular wave pulse generator, and a driving circuit for producing square wave pulses for driving the on-off type electromagnetic valve from the control signals of the proportional and integration circuit and of the triangular wave pulse, generator for controlling the air-fuel ratio to a valve approximately equal to the stoichiometric air-fuel ratio.

Abstract: An electronic fuel injection control internal combustion engine which is provided with a feedback control system for maintaining a predetermined constant idling speed and a system for controlling the operation of the fuel injector during the deceleration condition of the engine. A value of the rotational speed when the fuel injector is stopped or recovered is increased during the deceleration condition of the engine.

Abstract: Transient fuel control apparatus for an above the throttle fuel injected internal combustion engine includes apparatus effective to measure the time rate of change of throttle position and periodically derive therefrom a first transient correction number, apparatus effective to generate a first order lag filtered induction passage pressure signal, apparatus effective to derive rate of change of the induction passage pressure relative to the filtered induction passage pressure signal and derived therefrom a second transient fuel correction number and apparatus effective to modify the fuel injected into the induction passage from the quantity normally injected during steady state engine operation by an amount derived from the arithmetic sum of the first and second transient fuel correction numbers.

Abstract: A fuel injection control system is disclosed for an internal combustion engine having fuel injectors. The system comprises fuel cut-off means operable for rendering some of the fuel injectors inoperative only when the engine speed exceeds a first predetermined value during engine deceleration and for rendering the remaining fuel injectors inoperative only when the engine speed exceeds a second predetermined value higher than the first predetermined value during engine deceleration. Control means is provided for increasing the second predetermined value when rapid engine deceleration occurs.

Abstract: Applicant's invention includes an improved fuel metering system which is particularly suitable for use with spark ignition and internal combustion engines controlled by digital computers programed to calculate repetitively a value representing a current transfer rate of the intake surface fuel and the calculated value being used to modify the rate at which fuel otherwise would be metered into the engine's intake passage. In particular, modification of the rate at which fuel is metered into the engine's intake passage takes into account the current equilibrium intake surface fuel quantity, the current intake system time constant, and the current actual intake surface fuel. From these quantities the current trend for rate of intake surface fuel is calculated. In a calculation of the current actual intake surface fuel, a previous value of the actual intake surface fuel is used in combination with a previous value of the transfer rate of intake surface fuel. Additionally, a clock is used to establish a time span.

Abstract: The acceleration of an internal combustion engine is detected for generating at least one electrical signal indicating when acceleration exceeds a predetermined degree. In response to this signal, the fuel feeding rate of the engine is instantly increased by a predetermined increment. After each increasing operation is executed, the increased fuel feeding rate is decreased with a variable reduction rate. The variable reduction rate, according to the present invention, is decreased in accordance with the lapse of time after the increasing operation has been executed.

Abstract: A fuel injection system is proposed which can be triggered in such a manner that when control signals characterizing engine overrunning are present the fuel injection is interrupted. The fuel injection system includes metering valves, each of which is assigned one regulating valve, the movable valve element of which can be exposed on one side to the fuel pressure downstream of the pertinent metering valve and on the other side to the pressure in a control pressure line, which is limited on one side by a control throttle and on the other side by a control pressure valve. During engine overrunning, an electromagnetic valve which is disposed in a bypass that bypasses the control throttle or the control pressure valve or an electromagnetic valve in the control pressure line can be controlled in such a manner that the fuel pressure in the control pressure line increases and the regulating valves close, as a result of which the fuel injection is interrupted.

Abstract: A fuel injection control system is disclosed for an internal combustion engine having fuel injectors. The system comprises fuel-cut means operable for rendering some of the fuel injectors inoperative only when the engine speed exceeds a first predetermined value during engine deceleration and for rendering the remaining fuel injectors inoperative when the engine speed exceeds a second predetermined value higher than the first predetermined value during engine deceleration. Control means is provided for rendering the fuel-cut means inoperative when rapid engine deceleration occurs, thereby permitting the operation of all of the fuel injectors regardless of the engine speed.

Abstract: An engine control system is provided with a memory having an area addressed by two parameters chosen out of a group of throttle valve position, manifold pressure and engine rotation number, memorizing digital forms of predetermined fuel injection quantities plotted at points separated with a given distance. The values stored in those areas are read out to give a digital form of fuel injection quantity addressed with said parameters introduced by the sensors during the engine operation. The read-out value is multiplied by a coefficient concerning at least one of such detected values as air pressure, aspirated air temperature and engine temperature in order to give a corrected quantity with which the fuel injection is controlled. In this invention the digital controlling quantities stored in the first memory are plotted with short interval and high accuracy where the throttle opening angle is small and the interval is increased with increasing throttle opening angle.

Abstract: An apparatus and a method for controlling an internal combustion engine are disclosed, wherein upon deceleration of the engine, fuel injection is interrupted on the basis of determination of an engine operating condition to interrupt the fuel injection, while the fuel injection is then restored on the basis of determination of an engine operating condition to restore the fuel injection. When the determination is made such that the fuel injection is to be restored, the ignition timing determined in dependence on the prevailing engine operating condition is delayed. The delayed ignition timing is progressively advanced after restoration of the fuel injection to regain the original ignition timing determined in dependence on the prevailing engine operating condition.

Abstract: There is described a method and an apparatus for use with the fuel preparation system of an internal combustion engine, for example, a fuel injection system which operates injection valves with electrical control pulses. When the gas pedal of a vehicle is actuated abruptly, the air flow measuring device of such systems is subject to oscillations around its equilibrium point, and the initial one of these swings is used to cause enrichment of the fuel-air mixture. The return swing generates an undesired lean signal which is suppressed by a "damping circuit". In addition, there is provided mixture enriching during steady applications of the gas pedal by means of a time-decaying enrichment signal generated by a slow acting circuit which operates in superposition to the action of the damping circuit. Both circuits may be suppressed by a blocking circuit during certain engine conditions, for example, during engine starting and engine overrunning as well as on the basis of temperature.

Abstract: A fuel supply system for an internal combustion engine which includes sensors that signal the condition of engine braking (negative output torque) and which shut off fuel during such a condition. According to the invention, there is provided a special circuit which recognizes the termination of the fuel shut-off phase during engine braking and which causes excess fuel to be admitted to the engine just after the resumption of fuel supply after engine braking. The excess fuel is supplied in order to overcome fuel starvation due to condensation of fuel on induction tube walls which had cooled off during overrunning. The special fuel boost circuit receives information related to the air temperature and the air flow rate in the induction tube and uses it to adjust the time constant of a multivibrator which controls the amount of fuel added.

Abstract: A system for increasing the fuel feed in internal combustion engines during acceleration in order to ensure better performance comprising an acceleration detector, an enrichment stage, a proportionating member associated with a differentiating member, all connected to be responsive to at least one sensing member whose output signal is variable according to the engine operating conditions. The operating parameters sensed may be, for example, speed, air flow rate in the intake manifold, starting conditions, as well as the temperature of the internal combustion engine.

Abstract: An electronic engine control apparatus controls the engine on a basis of the outputs of the digital processor which arithmetically processes output signals from plural sensors for detecting the operating conditions of the engine. Whether or not a pulse to be generated in timing with the rotation of the engine has been generated within a preset period of time, as specified by the digital processor, is checked. If the pulse is generated, a timer for measuring the preset period is cleared. If the pulse is not generated within the preset period, a signal indicating the stopping of the engine is generated, whereby an interrupt signal is generated to cause the digital processor to process the interrupt.

Abstract: In order to prevent undesirable abrupt changes in engine torque when the fuel supply to the engine is shut off at the onset of engine braking, the invention provides the gradual decrease of the amount of fuel supplied to the engine beginning with the onset of engine braking and continuing until fuel has decreased to approximately 80 percent of the normal amount at which time the fuel is shut off entirely. When engine braking stops or when the operator indicates a demand for acceleration, the fuel supply is initiated at the level of approximately 80 percent of normal and is increased thereafter up to the normal amount according to a second selectable function of time.

Abstract: An acceleration signal detector is provided for detecting an acceleration condition of an engine based on the open-and-close operation of a throttle valve. Switching arrangements associated with the throttle valve are provided for detecting the fully closed condition of the throttle valve and for detecting a partially closed condition of the throttle valve. Signal processing apparatus receives output signals from the switching arrangements, and a change in the output of the means for detecting a partially closed condition subsequent to a change in the output of the means for detecting the fully closed condition is indicative of acceleration. This arrangement eliminates erroneous signals that might otherwise be caused by chattering of switch contacts.

Abstract: An electronic controlled fuel injection system is disclosed for use in an internal combustion engine including a plurality of cylinders each fitted with a fuel injection valve. The system comprises a fuel injection control circuit timed to engine rotation for providing a drive pulse signal to the fuel injection valves. A deceleration detecting circuit detects deceleration of the engine in accordance with the positions of the associated throttle valve and foot brake. A coupling circuit is responsive to engine rotational speed for allowing or impeding the passage of the drive pulse signal to the fuel injection valves during deceleration.

Abstract: An electronic controller for an internal combustion engine provides a ratio control signal corresponding to a respective air/fuel ratio, and responds to an air flow signal, a fuel flow signal and the ratio control signal to control fuel flow as to make the ratio of air flow to fuel flow substantially equal to said respective air/fuel ratio. The ratio control signal is developed from a base run ratio control signal as modified in response to various parameters such as engine temperature, manifold pressure, idle, manifold vacuum, fuel temperature, wide open throttle, engine speed, and start. The controller also provides a speed-up circuit for promptly responding to change in air flow and dynamic braking for the fuel metering pump. The pump speed circuit includes a range extender.

Abstract: Apparatus for controlling the number of enabled cylinders of an internal combustion engine during deceleration comprises a plurality of comparators responsive to a signal indicative of the engine rotational speed upon deceleration of the engine. The threshold voltages of the comparators are arranged stepwise so that each comparator produces an output signal when the engine speed falls below each threshold voltage. The output signals of the comparators are supplied to logic circuits to control a plurality of switches via which the fuel injection control pulse signal is respectively applied to fuel injection valves to increase in a stepwise fashion the number of enabled cylinders from the fuel cut-off state thereby preventing occurrence of impacts or shocks in the transition period of reactivation of the cylinders upon deceleration.

Abstract: The engine crankshaft rotational speed is detected to be compared with stepwise arranged threshold speeds so as to stepwise enable fuel injection valves of respective cylinders during deceleration of the engine. Accordingly, the number of enabled cylinders is increased in a stepwise manner from a fuel cut-off state as the engine rotational speed decreases to prevent engine stall, while occurrence of shocks upon reactivation of cylinders is avoided. The threshold speeds are controlled in accordance with the variation of engine load which may be increased upon operation of auxiliary power consuming units, such as an air conditioner the compressor of which is driven by the engine, for preventing undesirable vibrations of the engine during the stepwise reactivation of the cylinders.

Abstract: An electronic fuel injection control includes a main fuel control circuit which operates to control fuel flow to the engine by controlling the duration of engine-synchronized fuel valve opening pulses in accordance with at least one engine parameter. An auxiliary pulse source is arranged to provide extra unsynchronized pulses to improve the acceleration characteristics of the control, such pulses being produced when the throttle is opened. A muting circuit is provided which operates for a fixed period following closing movement of the throttle, to prevent the auxiliary pulse source responding to throttle opening during said period. The muting circuit prevents excess fuelling during gear changes etc.