A switch control circuit controls a switch element connected to a primary coil of an ignition coil in accordance with an ignition signal. The switch element includes a transistor and a protection element connected between a collector and gate of the transistor. The switch control circuit uses a voltage at a gate terminal controlling the transistor or a voltage corresponding to a collector current of the transistor as a detection voltage and generates a status detection signal corresponding to a change in the detection voltage.

Energization abnormality of a switch element of an internal combustion engine ignition device is detected appropriately. To this end, in an internal combustion engine ignition device that includes an ignition coil and an ignition plug, the ignition coil includes a primary coil including a main primary coil and a sub primary coil and a secondary coil that generates secondary current in response to a voltage variation generated in the primary coil. The internal combustion engine ignition device includes a main switch element that performs energization/deenergization of the main primary coil in a first direction, a sub primary coil magnetic flux generation state switching unit capable of switching between a forward direction magnetic flux generation state in which energization of the sub primary coil in the first direction is performed and an opposite direction magnetic flux generation state in which energization of the sub primary coil in a second direction is performed, and an abnormality detection section that detects energization abnormality to the sub primary coil. The abnormality detection section is configured so as to detect energization abnormality on the basis of overlap between energization in the first direction and energization in the second direction of the sub primary coil.

Energization abnormality of a switch element of an internal combustion engine ignition device is detected appropriately. To this end, in an internal combustion engine ignition device that includes an ignition coil and an ignition plug, the ignition coil includes a primary coil including a main primary coil and a sub primary coil and a secondary coil that generates secondary current in response to a voltage variation generated in the primary coil. The internal combustion engine ignition device includes a main switch element that performs energization/deenergization of the main primary coil in a first direction, a sub primary coil magnetic flux generation state switching unit capable of switching between a forward direction magnetic flux generation state in which energization of the sub primary coil in the first direction is performed and an opposite direction magnetic flux generation state in which energization of the sub primary coil in a second direction is performed, and an abnormality detection section that detects energization abnormality to the sub primary coil. The abnormality detection section is configured so as to detect energization abnormality on the basis of overlap between energization in the first direction and energization in the second direction of the sub primary coil.

An ignition apparatus for internal combustion engine includes an ignition coil in which a main primary coil and an auxiliary primary coil are magnetically coupled with a secondary coil that is connected to a spark plug. In the ignition apparatus, a main ignition circuit unit controls energization of the main primary coil and performs a main ignition operation in which a spark discharge is generated in the spark plug. An energy supply circuit unit controls energization of the auxiliary primary coil and performs an energy supply operation in which a current that has the same polarity as a secondary current that flows through the secondary coil as a result of the main ignition operation is superimposed on the secondary current. The auxiliary primary coil includes a plurality of auxiliary-primary-coil portions. The energy supply circuit unit performs the energy supply operation using one or more of the plurality of auxiliary-primary-coil portions.

An ignition apparatus for internal combustion engine includes an ignition coil in which a main primary coil and an auxiliary primary coil are magnetically coupled with a secondary coil that is connected to a spark plug. In the ignition apparatus, a main ignition circuit unit controls energization of the main primary coil and performs a main ignition operation in which a spark discharge is generated in the spark plug. An energy supply circuit unit controls energization of the auxiliary primary coil and performs an energy supply operation in which a current that has the same polarity as a secondary current that flows through the secondary coil as a result of the main ignition operation is superimposed on the secondary current. The auxiliary primary coil includes a plurality of auxiliary-primary-coil portions. The energy supply circuit unit performs the energy supply operation using one or more of the plurality of auxiliary-primary-coil portions.

An internal combustion engine ignition device includes an ignition coil, an ignition plug, a main ignition circuit, and an energy input circuit. A first switching element of the main ignition circuit performs energization and interruption of energization to a first coil part of a primary coil to generate an induced electromotive force using a DC voltage. A second switching element of the energy input circuit performs energization and interruption of energization to a second coil part of the primary coil to keep a discharge current in a secondary coil within an intended range directly using the DC voltage, after the induced electromotive force has been generated. A soft-off circuit of the energy input circuit slows a turn-off speed of the second switching element. The energy input circuit is configured to, when decreasing a signal voltage added to a gate of the second switching element, execute a first decreasing stage of decreasing the signal voltage until it reaches the vicinity of a gate-source threshold voltage and a second decreasing stage of gradually decreasing the signal voltage in the vicinity of the threshold voltage.

An ignition control device includes an ignition coil, a main ignition circuit unit for performing a main ignition operation, and an energy input circuit unit for performing an energy input operation. A main ignition signal generation circuit generates a main ignition signal such that a point in time when a waiting time has passed from a detection start time of a first signal of an ignition control signal at which a signal level of the ignition control signal changed from a first level to a second level for the first time, and the signal level of the ignition control signal is the second level, is a start of the main ignition signal, and a detection end time of a second signal of the ignition control signal at which the signal level of the ignition control signal shifts to the first level thereafter is an end of the main ignition signal.

An ignition control device includes an ignition coil, a main ignition circuit unit for performing a main ignition operation, and an energy input circuit unit for performing an energy input operation. A main ignition signal generation circuit generates a main ignition signal such that a point in time when a waiting time has passed from a detection start time of a first signal of an ignition control signal at which a signal level of the ignition control signal changed from a first level to a second level for the first time, and the signal level of the ignition control signal is the second level, is a start of the main ignition signal, and a detection end time of a second signal of the ignition control signal at which the signal level of the ignition control signal shifts to the first level thereafter is an end of the main ignition signal.

There is provided an ignition apparatus that makes it possible that after a spark discharge starts, a secondary current is reduced so that a plug is suppressed from being consumed. The ignition apparatus is provided with an ignition coil including a primary coil, a secondary coil, and a tertiary coil, a first switching circuit for performing on/off-switching of energization of the primary coil from a power source, a second switching circuit for performing on/off-switching of energization of the tertiary coil, and a controller that performs on/off-control of the first switching circuit so as to generate a secondary current in the secondary coil, thereby causing a spark discharge in an ignition plug, and then turns on the second switching circuit so as to reduce the secondary current through a change in flux in the tertiary coil.

There is provided an ignition apparatus that makes it possible that after a spark discharge starts, a secondary current is reduced so that a plug is suppressed from being consumed. The ignition apparatus is provided with an ignition coil including a primary coil, a secondary coil, and a tertiary coil, a first switching circuit for performing on/off-switching of energization of the primary coil from a power source, a second switching circuit for performing on/off-switching of energization of the tertiary coil, and a controller that performs on/off-control of the first switching circuit so as to generate a secondary current in the secondary coil, thereby causing a spark discharge in an ignition plug, and then turns on the second switching circuit so as to reduce the secondary current through a change in flux in the tertiary coil.