Abstract: An ignition timing control method and an apparatus for internal combustion engines in which the ignition timing of the engine is calculated from a base value obtained by detecting a first operation state of the engine and from a learned correction value obtained in accordance with the record content of a nonvolatile memory, the ignition timing being corrected by rewriting the nonvolatile memory in accordance with the detection result of second and third driving states of the engine, as desired.

Abstract: A method for controlling the air-fuel ratio in an internal combustion engine in which the correction of a base air-fuel ratio is carried out on the basis of the determination as to whether the base air-fuel ratio is on the richer or the leaner side of the air-fuel ratio corresponding to optimum specific fuel consumption, the determination being carried out by comparing four driving state indicating signals at different air-fuel ratios with each other, the correction being directed to bringing the base air-fuel ratio closer to the air-fuel ratio corresponding to the optimum specific fuel consumption.

Abstract: In a method and an apparatus for optimum control of an internal combustion engine, an air-fuel ratio is dithered by a dither amount from a basic air-fuel ratio and the engine is operated with the dithered air-fuel ratio. A resultant change of the output state of the engine is detected, and the direction of improving fuel consumption is decided by the change of the output state of the engine so that the basic air-fuel ratio is changed in that direction. Either the dither period during which the engine is operated with different selected air-fuel ratios or the dither amount is determined with elevated precision by a signal detected in association with the output state of the engine.

Abstract: Supercharging pressure produced by a supercharger driven by the exhaust gasses is detected so that frequency of combustion in an internal combustion engine is reduced to lower the engine output power. In order to reduce the frequency of combustion, the number of times of fuel injection may be thinned out or fuel injection into one or some of the cylinders of the engine may be stopped for a given period of time. Alternatively, the frequency of ignition may be reduced or ignition in one or some of the cylinders may be stopped for a given period of time. The control of fuel injection and the control of ignition may be combined. A microcomputer may be used to perform the method according to the present invention where the microprocessor thereof is arranged to execute a main routine and an interrupt service routine. In the main routine, data related to the supercharging pressure is stored in a memory, and the interrupt service routine, fuel injection and/or ignition is performed.

Abstract: Spark ignition timing of an internal combustion engine is oscillated on each side of a variable reference setting during successive ignition phases and the resultant engine speed is detected during at least three successive phases. The detected engine speed values are compared one against each other to determine whether they satisfy one of two specified conditions. The variable reference is adjusted in a direction toward an optimum position depending on which one of the conditions is satisfied. At least one of controlled parameters including the magnitude of the oscillated setting with respect to the variable reference, the length of the ignition phase and the amount of the adjusted reference setting, is varied as a function of an engine operating parameter.

Abstract: A system for controlling the air-fuel ratio in which the amount of fuel injected into the engine is controlled in accordance with the flow rate of air passing through an air intake pipe including a throttle valve for introducing the air into the engine and the engine operating conditions. A bypass of the air intake pipe is opened or closed to change the air-fuel ratio of the mixture to slightly richer and leaner sides of a basic air-fuel ratio, and the change of the engine output conditions based on the change of the air-fuel ratio is used to correct the air-fuel ratio in an optimum direction. On the basis of a parameter indicating the engine operating conditions such as the detection value of the intake pipe pressure, a control is made to introduce the air which passed through the bypass to one of the upstream or downstream portion of the throttle valve.

Abstract: In an optimum control for an internal combustion engine, a engine is operated by dithering the value of a selected one of engine operating control variables from a value of the selected control variable which is obtained by calculation in accordance with detected values of operating parameters of the engine, and a direction of improving either one of a fuel consumption rate and an output of the engine is decided on the basis of a detected change of an engine operating condition, thereby correcting the value of the selected control variable. In the optimum control, the time period for detecting a change of an engine speed within the time period for effecting the dithering is increased or decreased as the engine speed increases or decreases, respectively. Thus, this optimum control makes it possible to perform accurate control with a reduced dither quantity and a shorter dither period than previously.

Abstract: In the optimum control for an internal combustion engine wherein the engine is operated by dithering a value of a selected one of engine operating control variables from a value of the selected control variable which is obtained by calculation in accordance with detected values of operating parameters of the engine, and a direction of improving either one of a fuel consumption rate and an output of the engine is decided on the basis of a detected change of an engine operating condition, thereby correcting the calculated value of the selected control variable, during the time period of each dithered engine operation, an engine speed is detected two or more times and used for deciding the direction of a change of the engine speed, thereby providing an improved optimum control method and apparatus for internal combustion engines capable of preventing undesired correction control of the control variable from being effected in response to a change of the engine speed caused by any factor of disturbance.

Abstract: In an air-fuel ratio control system the air-fuel ratio is changed by changing the auxiliary air supply amount in a bypass path with respect to a main path for supplying air to the engine in the vicinity of an optimum air-fuel ratio. Signals representing the operating conditions such as rotational speed of the engine operated at the resulting different air-fuel ratios are detected at a plurality of operating points. The signals thus detected are compared and the fuel injection amount is regulated thereby to correct the air-fuel ratio so that the fuel consumption rate may become optimum.

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: Spark ignition timing of an internal combustion engine is oscillated on each side of a variable reference setting by varying it at stepwisely variable amounts during positive and negative swings and the resultant engine speed is detected in at least three successive phases. The detected engine speed values are compared one against each other to determine whether they satisfy one of two specified conditions. The variable reference is adjusted in a direction toward an optimum position depending on which one of the conditions is satisfied.

Abstract: A method and apparatus for optimum control for internal combustion engines employ computing means with memory means in which the values indicative of ignition timings and air-fuel ratios of an engine are preliminarily stored in the form of maps in accordance with parameters indicative of the operating conditions of the engine. At least one cycle of ignition timing optimization processing and at least one cycle of air-fuel ratio optimization processing are performed alternately so as to control the engine at the optimum ignition timing and air-fuel ratio for minimum fuel consumption.

Abstract: Spark ignition timing of an internal combustion engine is oscillated on opposite sides of the setting of a variable reference timing and the resultant engine speed is detected in at least three successive phases of the oscillation and stored in respective memories. The contents of the memories are compared with each other to detect whether they establish one of two predetermined relationships which occur exclusively in the absence of a manual command input to the engine. The variable reference setting is adjusted by a predetermined amount in a specified direction in response to the established relationship. The process is repeated so that the reference setting approaches an optimum advance angle at which the engine output torque is at a maximum. When the reference setting is at or near the optimum point or when a manual command engine input is present, the registered engine speed values establish a relationship other than the predetermined ones and the reference setting is not adjusted.

Abstract: A fuel injection device comprising a fuel pump, a constant pressure valve and a fuel nozzle connected to the fuel pump via a fuel feed passage. The constant pressure chamber of the constant pressure valve is arranged in the fuel feed passage. A flow control valve is arranged in the fuel feed passage between the constant pressure chamber and the fuel nozzle. The amount of the fuel injected from the fuel nozzle is controlled by the flow control valve so as to be directly proportional to the amount of the air sucked in. The constant pressure chamber is connected to the fuel nozzle via a bypass passage. An electromagnetic valve is arranged in the bypass passage and opened when an engine is accelerated and before the completion of the warm-up of an engine.

Abstract: The timing of spark ignition is set in normal operating conditions at a programed spark advance angle corresponding to the MBT (minimum spark advance for best torque). When knocking of the engine is detected by a vibration sensor, the ignition timing is delayed by a predetermined amount, e.g., 2.DELTA..theta., for each engine cycle that knocking is detected in synchronism with the rotation of the engine. When knocking is not detected, the ignition timing is advanced by another predetermined amount, for each engine cycle that knocking is not detected. e.g., .DELTA..theta.. In this method for controlling the spark timing, the amount of retardation, 2.DELTA..theta., is selected to be larger than the other amount of advance, .DELTA..theta..

Abstract: A method and apparatus for controlling the fuel supply of an internal combustion engine in which the primary fuel injection valve control pulses are derived on the basis of signals from sensors which monitor various engine variables, e.g. intake air flow rate, induction tube pressure, engine speed and/or engine and air temperatures and in which the fuel supply is entirely interrupted during the condition of engine overrunning (negative output torque). After the termination of engine overrunning, the normal fuel quantity which would be supplied on the basis of prevailing sensor signals is intentionally increased for a predetermined length of time to compensate for engine cooling during overrunning. This is done by increasing the pulse length of the injection control pulses. The apparatus includes transducers and circuits for recognizing the condition of overrunning and circuitry for supplying temporarily lengthened fuel control pulses.

Abstract: A spark-ignition timing of the internal combustion engine is normally set at an MBT (minimum spark advance for best torque). However, when a knocking of the engine is detected by a vibration sensor fixed to the engine, the ignition timing is retarded with respect to the MBT by an angle corresponding to either a non-knocking limit retard angle or a maximum retard angle determined by engine operating conditions whichever is smaller.

Abstract: A method of detecting knocking intensity of an internal combustion engine uses a detector for detecting vibration propagated within the engine and a first calculation circuit for obtaining an average value of vibration sensed by the vibration detector within a predetermined crank angle before the top dead center, and in which knocking is identified when the ratio between the above average value and the maximum value of vibration after the top dead center exceeds a predetermined value.

Abstract: A method for controlling the ignition timing for the internal combustion engine is disclosed. When it is decided that the engine load is large on the basis of the engine number of revolutions per minute and intake pressure. If the engine is in the knocking condition, a step lead angle is added to the present lead angle value in the range between a set lead angle and a minimum lead angle. If the engine is not in the knocking condition, on the other hand, a step lead angle is subtracted from the present lead angle value in the above-mentioned range. By contrast, when it is decided that the engine load is small on the basis of the engine r.p.m. and intake pressure. The lead angle control of the present lead angle value is stopped so that the present lead angle is set at the above-mentioned set lead angle or the minimum lead angle value.

Abstract: An electronically-controlled fuel injection system includes electromagnetic fuel injection valves each of which is mounted in each cylinder of an internal combustion engine, and the injection of fuel during the starting period of the engine is also effected only by these fuel injection valves. During the starting period of the engine, the duration of the opening of the fuel injection valves is controlled at a constant value irrespective of the rotational speed of the engine until the rotational speed reaches a value corresponding to the initial combustion of fuel in the engine, after which the duration of the opening of the fuel injection valves is controlled in relation to the rotational speed of the engine.