Abstract: A misfire detecting apparatus for an internal combustion engine detects only an ion current due to combustion of an air/fuel mixture regardless of a leakage current when combustion: takes place normally.

Abstract: A misfire detecting apparatus for an internal combustion engine which is capable of detecting only an ion current due to combustion of an air/fuel mixture regardless of occurrence of a leak current so far as the combustion takes place normally.

Abstract: To obtain a knock detection apparatus which may obtain a good knock pulse S/N even if an ionic current generation amount is changed by the change of a kind of fuel or plugs, a knock detection apparatus for detecting a knock generated, in an internal combustion engine, in which a vibratory component superimposed on an ionic current generated by combustion of fuel is extracted, the component that is equal to or more than a knock detection threshold value is shaped in waveform into a pulse waveform, a knock strength is calculated through counting and calculation process of the number of pulses of the pulse waveform by an engine controlling unit, an ignition timing is controlled on the basis of the knock strength, comprises a knock detection threshold value adjusting unit for changing the knock detection threshold value on the basis of information of an ionic current.

Abstract: To provide a combustion condition detecting apparatus for an internal combustion engine, which may well detect the combustion conditions such as discrimination of a combustion cylinder and knock generating condition and may reduce a circuit scale therefor, there are provided an ignition coil 21 provided for each cylinder; an ignition plug 20 for discharging by the application of the ignition high tension voltage to ignite mixture within the cylinder; a bias circuit 1 provided for each cylinder for applying a bias voltage to the ignition plug 20; an ionic current detection circuit 2 provided for each cylinder for detecting as an ionic current detection signal an ionic current 6 generated in the cylinder that is immediately after the combustion of the mixture; a knock signal processing circuit 4 provided one for a combination of a plurality of cylinders that are every two or more cylinders in ignition order on the basis of a sum of the ionic current detection signals; and an ECU 5 for detecting the combustion c

Abstract: To obtain a knock detection apparatus for an internal combustion engine which may obtain a good knock pulse S/N even if an ionic current generation amount is changed by the change of a kind of fuel or plugs, a vibratory component superimposed on an ionic current generated by combustion of fuel is extracted and shaped in waveform into a pulse waveform by comparison with a threshold value, the number of the pulses in the pulse waveform is calculated by a calculation unit, and a control of an ignition timing is performed on the basis of an output result of the calculation unit. The knock detection apparatus for an internal combustion engine comprises an integration circuit for integrating (charging) the vibratory component superimposed on the ionic current and a discharge circuit for discharging a predetermined amount of charge from the integrated charge. The threshold value is self-adjusted by a balance of charge/discharge between the integration circuit and the discharge circuit.

Abstract: A combustion state detecting apparatus for an internal combustion engine is imparted with facility for determining discriminatively the causes for non-occurrence of combustion.

Abstract: An ignition apparatus for an internal combustion engine is provided which is simple in the circuit arrangement and highly reliable in operation. An electromagnetic pickup coil generates an ignition signal having a magnitude proportional to the number of revolutions per minute of the engine in synchrony with the rotation thereof for controlling an ignition coil. A waveform shaper in the form of a comparator shapes the ignition signal from the pickup coil into a signal containing a pulse having a rising edge and a falling edge. An integrator integrates the ignition signal from the pickup coil to provide a rpm voltage representative of the number of revolutions per minute of the engine. A signal level controller controls the voltage level of the ignition signal based on the rpm voltage generated by the integrator. A current absorber absorbs from the ignition signal a current in accordance with the voltage of a power supply which powers the ignition coil.