An ignition coil control system includes: a first ignition coil; a second ignition coil; a spark plug generating spark discharge by a discharge current generated in the first ignition coil and the second ignition coil; and an ignition controller that controls spark discharge of the electrode by adjusting an amount and duration of the discharge current of the first ignition coil and the second ignition coil based on a step pulse signal including different voltages transmitted from an engine control unit (ECU).

Ignitability of a fuel by a spark plug is improved while an increase in the number of ignition coils is suppressed. A control device for an internal combustion engine includes an ignition control unit 83 which controls energization of an ignition coil 300a and an ignition coil 300b which each provide electric energy to a spark plug which discharges in a cylinder of an internal combustion engine to ignite a fuel, and a discharge amount detection unit which detects an inter-electrode voltage of the spark plug. After the ignition control unit 83 discharges the spark plug using the electric energy of the ignition coil 300a, the ignition control unit estimates a voltage which is supply-able from the ignition coil 300a to the spark plug, and controls energization of the ignition coil so as to supply the electric energy of the second ignition coil 300b to the spark plug when a difference d between the estimated supply-able voltage and a required voltage based on the voltage detected by the discharge amount detection unit is equal to or less than a predetermined threshold value.

An ignition coil control device includes: an energization control unit that controls to energize an ignition coil by first energization control and second energization control shorter in energization time than the first energization control; a cruise area determination unit that determines that a driving area of a vehicle is located in a cruise area on the basis of a throttle opening and an engine speed; and an integration counter that is incremented every predetermined time when the first energization control is being executed in the cruise area and is decremented every predetermined time in other cases. When a counter value of the integration counter reaches an upper limit value, a cooling process of switching from the first energization control to the second energization control is executed. Such ignition coil control device can appropriately switch energization time while preventing excessive heating of an ignition coil without using a current sensor.

A method of controlling an ignitor for a spark-ignition engine includes receiving, by a controller, at least one of fuel quality data regarding a fuel for the spark-ignition engine or a characteristic regarding the ignitor for the spark-ignition engine. The method additionally includes controlling, by the controller, an ignition energy characteristic of the ignitor in response to the at least one of the fuel quality data regarding the fuel or the characteristic regarding the ignitor for the spark-ignition engine.

A method of controlling an ignitor for a spark-ignition engine includes receiving, by a controller, at least one of fuel quality data regarding a fuel for the spark-ignition engine or a characteristic regarding the ignitor for the spark-ignition engine. The method additionally includes controlling, by the controller, an ignition energy characteristic of the ignitor in response to the at least one of the fuel quality data regarding the fuel or the characteristic regarding the ignitor for the spark-ignition engine.

An engine apparatus includes an ignition control section and an injection control section. When the partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be lower when a swirl flow is gentle than when the swirl flow is intense.

An engine control apparatus includes an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be lower when an in-cylinder temperature specified by an in-cylinder temperature specification section is high than when the in-cylinder temperature is low.

A control apparatus for a compression-ignition type engine is applied to an engine capable of carrying out partial compression ignition combustion in which an air-fuel mixture is subjected to CI combustion by self-ignition. The control apparatus creates a lean A/F environment where an air-fuel ratio as a ratio between air and fuel in a cylinder exceeds 20 and is lower than 35, or a lean G/F environment where a gas air-fuel ratio as a ratio between entire gas and the fuel in the cylinder exceeds 18 and is lower than 50 and the air-fuel ratio substantially matches a stoichiometric air-fuel ratio. Prior to planned timing of the CI combustion, in the lean A/F environment or the lean G/F environment, the control apparatus causes an ignition plug to generate a spark and to generate a high-temperature portion.

An engine control apparatus includes an ignition control section and an injection control section. When the partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. The energy of the preceding ignition is set to be higher when fuel concentration specified by a fuel concentration specification section is low than when the fuel concentration is high.

Ignitability of a fuel by a spark plug is improved while an increase in the number of ignition coils is suppressed. A control device for an internal combustion engine includes an ignition control unit 83 which controls energization of an ignition coil 300a and an ignition coil 300b which each provide electric energy to a spark plug which discharges in a cylinder of an internal combustion engine to ignite a fuel, and a discharge amount detection unit which detects an inter-electrode voltage of the spark plug. After the ignition control unit 83 discharges the spark plug using the electric energy of the ignition coil 300a, the ignition control unit estimates a voltage which is supply-able from the ignition coil 300a to the spark plug, and controls energization of the ignition coil so as to supply the electric energy of the second ignition coil 300b to the spark plug when a difference d between the estimated supply-able voltage and a required voltage based on the voltage detected by the discharge amount detection unit is equal to or less than a predetermined threshold value.