In an ignition device, a second circuit energizes a primary coil from its negative side in a first direction to thereby maintain energization of a second coil in a second direction during spark discharge started by a first circuit. The maintained energization continuously supplies energy to a spark plug, thus performing a continuation of the spark discharge. The first direction is opposite to a direction of energization of the primary coil carried out by the first circuit, and the second direction is the same as a direction of energization of the second coil that has been started based on the first circuit. A humidity detection unit detects humidity of intake air into an engine. The control section controls the first circuit to advance start timing of the spark discharge generated by the first circuit in accordance with an increase in the humidity of the intake air.

An ignition apparatus for an internal combustion engine is provided. The ignition apparatus includes an ECU. The ECU calculates a target value E* of an energy input amount of energy inputted into a spark plug based on an in-cylinder flow velocity v, a cylinder pressure P, and an air-fuel ratio AFR. The ECU also calculates a command value I* of a secondary current based on the in-cylinder flow velocity and control an operation of a second circuit according to the target value E* and the command value I*. The calculation of the target value E* using the in-cylinder flow velocity v, the cylinder pressure P, and the air fuel ratio AFR enables the energy input amount to be controlled according to the operating state of the internal combustion engine. The calculation of the command value I* based on the in-cylinder flow velocity v enables the secondary current to be controlled so as to eliminate a risk of the blowout of sparks. The ignition apparatus is, thus, capable of variably changing the amount of energy inputted to the spark plug to improve the fuel consumption.

An ignition apparatus for internal combustion engines is provided. The ignition apparatus is equipped with an ECU. The ECU monitors a path length of a discharge of a spark for a period of time in which a second circuit delivers or inputs energy in the form of a threshold value determination. When the path length has become too short, the ECU determines that ignition is expected to be delayed and then selects a special mode to control the delay of the ignition. The ECU increase a target value of an energy input amount. This enables the delay of ignition resulting from a short extension of the path length to be minimized. The ignition apparatus equipped with the second circuit to continue the discharge of sparks is, thus, capable of reducing a variation in ignition without the need for uniformly increasing the energy input amount.

In an ignition device, a second circuit energizes a primary coil from its negative side in a first direction to thereby maintain energization of a second coil in a second direction during spark discharge started by a first circuit. The maintained energization continuously supplies energy to a spark plug, thus performing a continuation of the spark discharge. The first direction is opposite to a direction of energization of the primary coil carried out by the first circuit, and the second direction is the same as a direction of energization of the second coil that has been started based on the first circuit. A humidity detection unit detects humidity of intake air into an engine. The control section controls the first circuit to advance start timing of the spark discharge generated by the first circuit in accordance with an increase in the humidity of the intake air.

In an ignition device, a second circuit energizes a primary coil from its negative side in a first direction to thereby maintain energization of a second coil in a second direction during spark discharge started by a first circuit. The maintained energization continuously supplies energy to a spark plug, thus performing a continuation of the spark discharge. The first direction is opposite to a direction of energization of the primary coil carried out by the first circuit, and the second direction is the same as a direction of energization of the second coil that has been started based on the first circuit. A humidity detection unit detects humidity of intake air into an engine. The control section controls the first circuit to advance start timing of the spark discharge generated by the first circuit in accordance with an increase in the humidity of the intake air.

The return circuit of the ignition device returns to the battery the current supplied to the primary coil by the operation of the second circuit, and the voltage detection unit detects the voltage VB. The operation stopping unit monitors the voltage VB and when it is determined that the voltage VB is excessive, that is, when the voltage VB exceeds the threshold voltage VBc, it stops the supply of energy by the second circuit. As a result, when a load dump state occurs, the supply of energy by the second circuit can be stopped. Thus, when a load dump state occurs by the operation of the second circuit, other devices can be protected from overvoltage.

The return circuit of the ignition device returns to the battery the current supplied to the primary coil by the operation of the second circuit, and the voltage detection unit detects the voltage VB. The operation stopping unit monitors the voltage VB and when it is determined that the voltage VB is excessive, that is, when the voltage VB exceeds the threshold voltage VBc, it stops the supply of energy by the second circuit. As a result, when a load dump state occurs, the supply of energy by the second circuit can be stopped. Thus, when a load dump state occurs by the operation of the second circuit, other devices can be protected from overvoltage.

According to an ignition device, a first switching unit applies a voltage between electrodes of by spark plug by turning on/off energization from an on-vehicle battery to a primary coil. Further, a second switching unit applies a voltage having the same direction as a spark discharge generated by turning on/off the first switching unit between the electrodes of the spark plug by supplying electrical energy accumulated in a booster circuit into a primary coil. Accordingly, it is possible to greatly reduce a complexity of the on/off switching of the first and second switching units compared to a conventional technology.

Provided are an ignition apparatus and an ignition control method capable of suppressing occurrence of a defect caused by a charge unit, which may occur when ignition of a combustible mixture in a combustion chamber of an internal combustion engine needs to be stopped. When a stop condition for stopping ignition of a combustible mixture in a combustion chamber (2) of an internal combustion engine (1) is satisfied, supply of plasma generation energy to an ignition plug (3) is stopped, and DC energy charged in a charge unit (42) is discharged.

An ignition apparatus includes a blow-off determining unit 5b. The blow-off determining unit 5b determines, when the value I2 of the time derivative of a secondary electric current exceeds a predetermined threshold value Z during a determination period, that blow-off has occurred; the determination period is a predetermined time period T from the start of a spark discharge by a main ignition circuit 3. Further, when it is determined that blow-off has occurred during a main ignition (full-transistor ignition), it is controlled to perform a continuing spark discharge after the main ignition in a next cycle. Moreover, a secondary electric current command value in performing the continuing spark discharge is set to an electric current value that is obtained by adding a predetermined electric current value to the secondary electric current value I2x immediately before the occurrence of blow-off. Consequently, in the next cycle, it is possible to reliably prevent blow-off, thereby reliably preventing misfire.