A method for ignition control in a combustion chamber of an internal combustion engine by means of acquiring an electric signal relating to ionizing currents emitted in said combustion chamber, comprising a step of detecting a substantially stepped trend of said electric signal and a consequent step of inhibiting a corrective action of an ignition advance and/or of a fuel injection limitation curve in the combustion chamber.

A method for ignition control in a combustion chamber of an internal combustion engine by means of acquiring an electric signal relating to ionizing currents emitted in said combustion chamber, comprising a step of detecting a substantially stepped trend of said electric signal and a consequent step of inhibiting a corrective action of an ignition advance and/or of a fuel injection limitation curve in the combustion chamber.

An object is to reduce the required numbers of connector pins and A/D converters, without degrading the detection accuracy. There is provided an ignition apparatus which includes: ignition plugs provided for multiple cylinders; an ignition coil provided for each cylinder, and having a primary coil and a secondary coil magnetically coupled to the primary coil and connected to the ignition plug; switching devices each for switching between application and shut-off of current to the primary coil; a primary-voltage-signal separator provided for each cylinder, for inputting thereto a voltage of the primary coil and outputting the voltage as a primary signal; a primary-signal combiner for electrically combining together each primary signal corresponding to each cylinder, to thereby output a composite primary signal; and a primary-voltage-information detector for inputting thereto the composite primary signal, to thereby output primary voltage information of each cylinder.

In an ignition control device for controlling operation of an ignition apparatus, an ignition section has first and second electrodes disposed in a combustion chamber of an internal combustion engine. A voltage application between the first and second electrodes enables a discharge to be generated between the first and second electrodes for igniting a gas mixture in the combustion chamber. A voltage application section performs at least one application of a determination voltage between the first and second electrodes. An occurrence ratio acquisition section acquires a discharge occurrence ratio at the ignition section for the at least one application of the determination voltage. A comparison section compares the discharge occurrence ratio acquired by the occurrence ratio acquisition section with a predetermined determination threshold to thereby determine a degree of wear of at least one of the first and second electrodes.

In an ignition control device for controlling operation of an ignition apparatus, an ignition section has first and second electrodes disposed in a combustion chamber of an internal combustion engine. A voltage application between the first and second electrodes enables a discharge to be generated between the first and second electrodes for igniting a gas mixture in the combustion chamber. A voltage application section performs at least one application of a determination voltage between the first and second electrodes. An occurrence ratio acquisition section acquires a discharge occurrence ratio at the ignition section for the at least one application of the determination voltage. A comparison section compares the discharge occurrence ratio acquired by the occurrence ratio acquisition section with a predetermined determination threshold to thereby determine a degree of wear of at least one of the first and second electrodes.

An ion current detection circuit is for detecting an ion current flowing through a spark plug for an internal combustion engine. A detection terminal is to be electrically connected to the spark plug. A reference potential is to be supplied to a reference terminal. At least one protection diode is provided between the detection terminal and the reference terminal. A current detection unit causes a detection current to flow between the detection terminal and the at least one protection diode. A current compensation unit causes a compensation current to flow between the detection terminal and the at least one protection diode.

An ion current detection circuit is for detecting an ion current flowing through a spark plug for an internal combustion engine. A detection terminal is to be electrically connected to the spark plug. A reference potential is to be supplied to a reference terminal. At least one protection diode is provided between the detection terminal and the reference terminal. A current detection unit causes a detection current to flow between the detection terminal and the at least one protection diode. A current compensation unit causes a compensation current to flow between the detection terminal and the at least one protection diode.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may be implemented in part by the controller and comprises determining a shaft angle of an engine shaft; supplying, to an ion sensor fluidly coupled to a combustion chamber of the engine a low voltage at a beginning of a combustion cycle to generate an ion sensor current and a high voltage during an ionization voltage window based at least in part on the shaft angle, wherein the low voltage is configured to prevent premature ignition of fuel in the combustion chamber and the high voltage exceeds the low voltage and is configured to increase the ion sensor current above a current threshold.

Due to changes in a flow of an air-fuel mixture in a cylinder, reliable ignition due to spark discharge may not be possible. Therefore, an ignition control unit 24 includes a secondary voltage calculation unit 31 that calculates an average value of a secondary voltage generated on a secondary side of an ignition coil, an irregular flow ratio calculation unit 32 that calculates a ratio of cycles in which the average value of the secondary voltage is equal to or less than a set average value with respect to a cycle of the internal combustion engine in a predetermined period as an irregular flow ratio indicating that the flow of the air-fuel mixture in the cylinder is irregular, and an ignition operation amount correction unit 37 that corrects an ignition operation amount so that the irregular flow ratio is equal to or less than the set ratio value that is the target to be reached of the irregular flow ratio.

Due to changes in a flow of an air-fuel mixture in a cylinder, reliable ignition due to spark discharge may not be possible. Therefore, an ignition control unit 24 includes a secondary voltage calculation unit 31 that calculates an average value of a secondary voltage generated on a secondary side of an ignition coil, an irregular flow ratio calculation unit 32 that calculates a ratio of cycles in which the average value of the secondary voltage is equal to or less than a set average value with respect to a cycle of the internal combustion engine in a predetermined period as an irregular flow ratio indicating that the flow of the air-fuel mixture in the cylinder is irregular, and an ignition operation amount correction unit 37 that corrects an ignition operation amount so that the irregular flow ratio is equal to or less than the set ratio value that is the target to be reached of the irregular flow ratio.