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.

A circuit configured to control a switching device to reduce a current in a charged coil is disclosed. The circuit is configured to monitor a kickback voltage generated by the decreasing current in the coil. The circuit is further configured to adjust a rate at which the current is reduced in order to limit the kickback voltage. Limiting the kickback voltage during shutdown can prevent a spark at a spark gap that is inductively coupled to the coil and can allow for greater flexibility in the time taken to shut down the coil without overheating components or generating an unwanted spark. Additional, limiting the kickback voltage during shutdown can allow for a pseudo ramp wave to control the circuit during the shutdown because voltage spikes cause by abrupt changes in the pseudo ramp wave are limited.

An ignition device for an internal combustion engine that uses fuels including hydrogen. The ignition device includes an ignition coil including a primary coil and a secondary coil, a power supply device, a switching element, a spark plug, and a limiting diode. The switching element performs switching between passage and interruption of a primary current. The spark plug causes discharge at a gap, based on a high voltage induced at the secondary coil. The limiting diode includes a Zener diode that is forward-biased when oriented in a direction from the one end to the other end of the secondary coil. A breakdown voltage of the limiting diode is higher than the maximum value of an ON-state voltage obtained by multiplication of a value of a direct-current voltage applied to the primary coil by a ratio of the number of turns of the secondary coil to that of the primary coil.

In an ignition apparatus, a deterioration determination circuit performs a deterioration determination task of (i) monitoring an absolute increase in a temperature parameter during a predetermined deterioration detection period that has been started since an energization command signal being inputted to a control circuit, and (ii) performing a comparison between the absolute increase in the temperature parameter and a predetermined deterioration detection threshold to thereby determine whether a level of deterioration of a switching circuit is within an acceptable level.

A method of detecting the breakdown voltage between the electrodes of a spark plug connected to an ignition coil for a cylinder ignition system, in an internal combustion engine, comprises a detection of an opening of the switch (105) on the primary winding (102) and a detection of a voltage on that primary winding (102), with the generation of a first signal (V.sub.1) representative of the voltage trend following the opening of the switch (105).

The first signal (V.sub.1) is then integrated and, following an identification of a breakdown at the ends of the spark plug (106), a breakdown voltage value is determined as a function of the value of the integrated signal at the time of the breakdown.

It is made possible to control ignition appropriately. An ignition device 1 for an internal combustion engine includes a spark coil 50 including: a primary side coil 51 connected to a direct current power supply 40 and a secondary side coil 52 magnetically connected to the primary side coil 51 and connected to an ignition plug 60; a switch element 30 that performs switching between energization and interruption of primary current I1 to the primary side coil 51; and a switch element controlling circuit 20 that controls the switch element 30 on the basis of an ignition controlling signal 51 supplied from an ECU 10. A turn-on delay adjustment circuit 22 that delays a control timing of the switch element 30 is disposed between the ECU 10 and the switch element 30 such that first resonance noise generated due to interruption of the primary current I1 to the primary side coil 51 is reduced.

An ignition device for an internal combustion engine includes an ignition coil, a first switch, a secondary current adjuster, and controller. The ignition coil includes a primary coil, a core, and a secondary coil. The first switch switches an energized state of the primary coil between an ON state and an OFF state. The secondary current adjuster adjusts a current value of a secondary current flowing through the secondary coil. The controller controls the secondary current adjuster so that a current value of the secondary current in at least a part of a charging period of the ignition plug, which is a period from when the energized state of the primary coil is switched from the ON state to the OFF state by the first switch to when dielectric breakdown occurs in the ignition plug, becomes smaller than a peak value of the secondary current after the dielectric breakdown occurs.

An ignition device for an internal combustion engine includes an ignition coil, a first switch, a secondary current adjuster, and controller The ignition coil includes a primary coil, a core, and a secondary coil. The first switch switches an energized state of the primary coil between an ON state and an OFF state. The secondary current adjuster adjusts a current value of a secondary current flowing through the secondary coil. The controller controls the secondary current adjuster so that a current value of the secondary current in at least a part of a charging period of the ignition plug, which is a period from when the energized state of the primary coil is switched from the ON state to the OFF state by the first switch to when dielectric breakdown occurs in the ignition plug, becomes smaller than a peak value of the secondary current after the dielectric breakdown occurs.

A semiconductor device for internal combustion engine ignition includes: a power semiconductor switching device that switches ON and OFF in accordance with a control signal provided by an external control circuit for causing a spark plug to produce sparks via an ignition coil and an external power source; an auxiliary voltage circuit that generates and applies an auxiliary voltage responsive to a collector voltage of the power semiconductor switching device to the gate of the power semiconductor switching device; and a constant current circuit that regulates current from the auxiliary voltage circuit to the gate of the power semiconductor switching device when a high-voltage surge originating from the external power source is applied to the auxiliary voltage circuit via a primary winding of the ignition 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.