Ignition apparatus
A current flowing in a sub-primary coil can be limited in an ignition apparatus in which a voltage, generated in a secondary coil at a timing when a current in a main primary coil is cut off, generates a secondary current, and then the sub-primary coil is energized so that a superimposition current is generated in the secondary coil and in which a sub-IC connected in series with the sub-primary coil is pulse-controlled so that a current flowing in the sub-primary coil is controlled and hence the superimposition current is controlled.
1. An ignition apparatus comprising:
a main primary coil that generates positive-direction energization magnetic flux when energized by a power source and generates opposite-direction de-energization magnetic flux when de-energized;
a main switching device that is connected with the main primary coil and performs switching between energization and de-energization of the main primary coil;
a sub-primary coil that generates magnetic flux having a direction the same as that of the de-energization magnetic flux when energized by the power source;
a sub-switching device that is connected with the sub-primary coil and performs switching between energization and de-energization of the sub-primary coil; and
a secondary coil whose one terminal is connected with an ignition plug and that is magnetically coupled with the main primary coil and the sub-primary coil so as to generate discharge energy,
wherein a voltage generated in the secondary coil at a timing when the main switching device is de-energized generates a secondary current; then, the sub-switching device is energized and hence the sub-primary coil is energized so that a superimposition current is generated in the secondary coil and a current flowing in the sub-primary coil is limited,
wherein a first terminal of the sub-primary coil is connected to the power source and a second terminal of the sub-primary coil is connected to the sub-switching device, and
wherein a gate voltage of the sub-switching device is controlled based on detection of the current flowing in the sub-primary coil.
2. The ignition apparatus according to claim 1 , wherein the current flowing in the sub-primary coil is limited by increasing a voltage between a collector and an emitter of the sub-switching device.
3. The ignition apparatus according to claim 2 , wherein the voltage between the collector and the emitter of the sub-switching device is variable.
4. The ignition apparatus according to claim 3 , wherein in a normal state where the voltage of the power source or a voltage to be applied to the ignition plug does not change, the current that flows in the sub-primary coil is set to be unlimited.
5. The ignition apparatus according to claim 2 , wherein the limit value of the current that flows in the sub-primary coil is set to 10 A through 20 A.
6. The ignition apparatus according to claim 1 , wherein a current limiting resistor is inserted into a path in which only the current flowing in the sub-primary coil flows.
7. The ignition apparatus according to claim 6 , wherein the current limiting resistor is formed of a variable resistor.
8. The ignition apparatus according to claim 7 , wherein in a normal state where the voltage of the power source or a voltage to be applied to the ignition plug does not change, the current that flows in the sub-primary coil is set to be unlimited.
9. The ignition apparatus according to claim 1 , wherein a limit value of the current that flows in the sub-primary coil is set to 10 A through 20 A.
10. An ignition apparatus comprising:
a main primary coil that generates positive-direction energization magnetic flux when energized by a power source and generates opposite-direction de-energization magnetic flux when de-energized;
a main switching device that is connected with the main primary coil and performs switching between energization and de-energization of the main primary coil;
a sub-primary coil that generates magnetic flux having a direction the same as that of the de-energization magnetic flux when energized by the power source;
a sub-switching device that is connected with the sub-primary coil and performs switching between energization and de-energization of the sub-primary coil;
a current limiting resistor having a first terminal connected to a first terminal of the sub-primary coil; and
a secondary coil whose one terminal is connected with an ignition plug and that is magnetically coupled with the main primary coil and the sub-primary coil so as to generate discharge energy,
wherein a voltage generated in the secondary coil at a timing when the main switching device is de-energized generates a secondary current; then, the sub-switching device is energized and hence the sub-primary coil is energized so that a superimposition current is generated in the secondary coil and a current flowing in the sub-primary coil is limited by the current limiting resistor,
wherein a second terminal of the sub-primary coil is connected to the power source and a second terminal of the current limiting resistor is connected to the sub-switching device.
11. An ignition apparatus comprising:
a main primary coil that generates positive-direction energization magnetic flux when energized by a power source and generates opposite-direction de-energization magnetic flux when de-energized;
a main switching device that is connected with the main primary coil and performs switching between energization and de-energization of the main primary coil;
a sub-primary coil that generates magnetic flux having a direction the same as that of the de-energization magnetic flux when energized by the power source;
a sub-switching device that is connected with the sub-primary coil and performs switching between energization and de-energization of the sub-primary coil; and
a secondary coil whose one terminal is connected with an ignition plug and that is magnetically coupled with the main primary coil and the sub-primary coil so as to generate discharge energy,
wherein a voltage generated in the secondary coil at a timing when the main switching device is de-energized generates a secondary current; then, the sub-switching device is energized and hence the sub-primary coil is energized so that a superimposition current is generated in the secondary coil, and
wherein a current flowing in the sub-primary coil is limited by increasing a voltage between a collector and an emitter of the sub-switching device.
12. The ignition apparatus according to claim 11 , wherein the voltage between the collector and the emitter of the sub-switching device is variable.
13. The ignition apparatus according to claim 12 , wherein in a normal state where the voltage of the power source or a voltage to be applied to the ignition plug does not change, the current that flows in the sub-primary coil is set to be unlimited.
14. The ignition apparatus according to claim 11 , wherein a limit value of the current that flows in the sub-primary coil is set to 10 A through 20 A.