Patent ID: 11891972
Assignee: DENSO CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  H | IPC F  H

Claim 8:
9. An ignition device for an internal combustion engine, comprising:
an ignition plug;
a primary coil that includes a predetermined winding;
a secondary coil configured to be magnetically linked to the primary coil and be connected to the ignition plug;
a main ignition circuit configured to supply and interrupt a current through the primary coil to accordingly cause a spark discharge to occur in the ignition plug;
an energy supply circuit configured to supply and stop electrical energy to the predeterminded winding of the primary coil to accordingly cause the spark discharge to continue;
a recirculation circuit configured to permit and prohibit current recirculation through a recirculation path including the predetermined winding; and
a controller configured to:
control the main ignition circuit,
send an interruption signal to the main ignition circuit to thereby cause the main ignition circuit to interrupt the current through the primary coil, and
determine a start time of a permission of the current recirculation by the recirculation circuit using, as a trigger, the interruption signal, and start the permission of the current recirculation at the determined start time when the current through the primary coil is interrupted, and
end the permission after a predetermined time period has elapsed since the start time;

wherein the controller is further configured to:
receive a main ignition signal of a high level or a low level,
energize the main ignition circuit at rising of the main ignition signal, and
use falling of the main ignition signal as the interruption signal to interrupt the main ignition circuit and start the permission of the current recirculation by the recirculation circuit at the falling of the main ignition signal.