Abstract: An ionic current detection apparatus for an internal combustion engine does not generate a false ionic current, and hence it does not generate a false knock component signal either, thereby avoiding an incorrect combustion determination or an incorrect knock determination. The apparatus detects an ionic current generated in spark plugs connected with secondary sides of a plurality of ignition coils, respectively, each of which generates a high ignition voltage immediately after firing of a corresponding combustion chamber. The ignition coils are arranged in such a manner that at least the directions of adjacent ignition coils do not coincide with one another. In addition, the ignition coils are fixed by a fixture, which has arrangement positions for the ignition coils predetermined according to the mounting directions thereof, in such a manner that the directions of adjacent ignition coils do not coincide with one another, the ignition coils being installed on the engine through the fixture.

Abstract: A combustion condition detecting apparatus for an internal combustion engine has a current distributor that distributes an ion current, a band pass filter which extracts a knock vibration component from a current distributor output, a knock determination section which outputs a knock pulse if the extracted knock vibration component is larger than a knock detection threshold value, a combustion determination section which outputs a combustion pulse when an current distributor output is larger than a combustion pulse threshold value, an ignition signal determination section which makes a determination on the basis of an ignition signal as to whether energization of an ignition coil for ignition in another cylinder is started, and an ion current limiting section which limits its ion current output to the current distributor during a predetermined time period after the start of energization of the ignition coil for ignition in the another cylinder.

Abstract: A control device for an internal combustion engine, including: an ion current detecting unit for detecting an ion current flowing between electrodes, via ions generated in a combustion chamber upon combustion, at a time when a voltage is applied to electrodes arranged in a combustion chamber of the internal combustion engine; a parameter extracting unit for extracting an ion current characteristics parameter correlating to an IMEP, from the ion current detected by the ion current detecting unit; an IMEP-related-information calculating unit for using the ion current characteristics parameter outputted from the parameter extracting unit, to calculate information relating to the IMEP of the internal combustion engine; and an internal combustion engine control unit for controlling operations of the internal combustion engine based on the output from the IMEP-related-information calculating unit.

Abstract: A control device for an internal combustion engine, including: an ion current detecting unit for detecting an ion current flowing between electrodes, via ions generated in a combustion chamber upon combustion, at a time when a voltage is applied to electrodes arranged in a combustion chamber of the internal combustion engine; a parameter extracting unit for extracting an ion current characteristics parameter correlating to an IMEP, from the ion current detected by the ion current detecting unit; an IMEP-related-information calculating unit for using the ion current characteristics parameter outputted from the parameter extracting unit, to calculate information relating to the IMEP of the internal combustion engine; and an internal combustion engine control unit for controlling operations of the internal combustion engine based on the output from the IMEP-related-information calculating unit.

Abstract: An ionic current detection apparatus for an internal combustion engine does not generate a false ionic current, and hence it does not generate a false knock component signal either, thereby avoiding an incorrect combustion determination or an incorrect knock determination. The apparatus detects an ionic current generated in spark plugs connected with secondary sides of a plurality of ignition coils, respectively, each of which generates a high ignition voltage immediately after firing of a corresponding combustion chamber. The ignition coils are arranged in such a manner that at least the directions of adjacent ignition coils do not coincide with one another. In addition, the ignition coils are fixed by a fixture, which has arrangement positions for the ignition coils predetermined according to the mounting directions thereof, in such a manner that the directions of adjacent ignition coils do not coincide with one another, the ignition coils being installed on the engine through the fixture.

Abstract: A combustion condition detecting apparatus for an internal combustion engine has a current distributor that distributes an ion current, a band pass filter which extracts a knock vibration component from a current distributor output, a knock determination section which outputs a knock pulse if the extracted knock vibration component is larger than a knock detection threshold value, a combustion determination section which outputs a combustion pulse when an current distributor output is larger than a combustion pulse threshold value, an ignition signal determination section which makes a determination on the basis of an ignition signal as to whether energization of an ignition coil for ignition in another cylinder is started, and an ion current limiting section which limits its ion current output to the current distributor during a predetermined time period after the start of energization of the ignition coil for ignition in the another cylinder.