Abstract: In a system for retarding an ignition timing of the engine depending on a signal from a knock detector, the knocking intensity and the knocking frequency are discriminated in accordance with the signal of the knock detector. On the basis of the discriminated results, the system provides a small amount of retard angle for ignition timing per one knocking when the knocking frequency is low, that is, the interval between knocking signals is long and the intensity of knocking is light. On the contrary, the system provides a large amount of retard angle when the interval is short and the intensity is heavy.

Abstract: An internal combustion engine ignition timing control system with knock control detects the knocking in an engine and the acceleration of the engine speed to control the ignition timing of the engine. The ignition timing of the engine is retarded in response to the detection of knocking in the engine and the amount of retard is increased as compared with the amount of retard provided under the steady-state condition when the knocking occurs during the acceleration operation of the engine and the frequency of occurrence of knocking is high.

Abstract: In an ignition timing control system, a knocking detector detects a knocking of the internal combustion engine. The ignition timing control circuit includes a cylinder switching signal generator circuit for generating a cylinder switching signal in synchronism with the rotation of the engine, a plurality of integrators each corresponding to each or a plurality of cylinders for producing a reference signal in response to the noise signal produced from the knocking detector, a plurality of analog switches for changing one of the integrators into ON-state in response to the cylinder switch signal, and a comparator having an input terminal supplied with the detection signal of the knocking detector and the other input terminal supplied with an integration output signal of the integrators, said comparator producing a knocking signal which retards the ignition timing of the engine when the detection signal is larger in amplitude than the integration signal.

Abstract: In a knocking discriminating system for an internal combustion engine, a knocking detecting signal obtained from a knocking sensor is passed through a band-pass filter for obtaining a sinusoidal waveform of approximately 8 KHz. The sinusoidal waveform signal is then applied to an A/D converter, the operational timing of which is controlled by a microcomputer, so that only a part of the knocking detecting signal nearby the peak portion is converted into digital values. A discrimination level is prepared from the average value of the digital values, and the knocking status is discriminated by comparing the maximum value of the digital values thus converted with the discriminating level.

Abstract: A spark timing control apparatus controls the spark timing to retard or advance in accordance with the output signal from a knock sensor. An accelerating condition of the engine is determined depending on a particular knock occurence patterns including; whether the interval of knock occurences is larger or small, the total amount of retard angles is larger or small, or the frequency of knock occurences. When the accelerating condition is determined, the advancing rate of the spark timing is increased until a steady state of the engine operation is determined based on the output signal of the knock sensor.

Abstract: In ignition timing control system for an internal combustion engine, a knocking detector is provided to detect knockings of the engine, and a control unit responsive to the knocking signals of the knocking detector to provide a variable retard amount signal per one knocking which depends on whether the occurrence of another knocking is decided before the lapse of a predetermined time interval from the decision of the knocking.