A method for operating an ignition coil is described, wherein a secondary voltage pulse is generated by feeding a primary voltage pulse into a transformer of the ignition coil, and a primary current, a primary voltage, a secondary current and/or a secondary voltage are measured, wherein the course of the primary current, the primary voltage, the secondary voltage and/or the secondary current are monitored and, when a malfunction is determined during subsequent primary voltage pulse, an error signal is generated which indicates that a malfunction has occurred during the previous primary voltage pulse and classifies the malfunction. In addition, a corresponding ignition coil is described.

An ignition system and a method for controlling an ignition system for a spark-ignited internal combustion engine are described, having a primary voltage generator for generating an ignition spark and a boost converter for maintaining an ignition spark. The method includes sending a signal from an engine control unit to the ignition system, in order to determine a predetermined ignition timing for triggering an ignition spark, sending an additional signal from the engine control unit to the ignition system, in order to determine a predetermined additional ignition timing for triggering an additional ignition spark, and sending a control signal for influencing the operating mode of the boost converter from the engine control unit to the ignition system between the signal and the additional signal.

An ignition coil has a primary coil and a secondary coil, a coil terminal, a connector terminal and a connector part. The connector part has a coil-side lead wire and a connector-side lead wire. The coil terminal has a coil-side fitting groove part into which the coil-side lead wire is fitted. An internal edge surface of the coil-side fitting groove part is formed internally to have a protruded curved surface. The connector terminal has a connector-side fitting groove part into which the connector-side lead wire is fitted. An internal edge surface of the connector-side fitting groove part is formed internally to have a protruded curved surface. The coil-side lead wire is inserted into the coil-side fitting groove part in a direction perpendicular to a longitudinal direction thereof. The connector-side lead wire is fitted into the connector-side fitting groove part in a direction perpendicular to a longitudinal direction thereof.

An ignition system for an internal combustion engine that utilizes a single primary coil and a single secondary coil to drive a pair of spark plugs. Current flowing in both a first direction and a second direction passes through the primary coil. The current flowing through the primary coil induces corresponding current in the secondary coil, which flows from the secondary coil to one of two spark plugs. Each spark plug is coupled to the secondary coil such that each of the two spark plugs receives current flowing only in a single direction. The current flowing through the ignition system can be from either a power source or created by the rotation of a flywheel having a series of magnet clusters.

To alleviate or eliminate a problem of unburned fuel discharged to the outside of a cylinder in a case in which an air fuel mixture is insufficiently combusted in a combustion chamber. During the expansion stroke in which a high voltage is applied to an ignition plug via an ignition coil, and a spark discharge is caused to occur at the ignition plug, thereby the air fuel mixture in the combustion chamber is ignited and combusted, in a case in which deterioration of combustion state is detected, a microwave electric field is created in the combustion chamber prior to an opening timing of an exhaust valve at an end stage of the expansion stroke, thereby plasma is generated and enlarged in the combustion chamber.

To alleviate or eliminate a problem of unburned fuel discharged to the outside of a cylinder in a case in which an air fuel mixture is insufficiently combusted in a combustion chamber. During the expansion stroke in which a high voltage is applied to an ignition plug via an ignition coil, and a spark discharge is caused to occur at the ignition plug, thereby the air fuel mixture in the combustion chamber is ignited and combusted, in a case in which deterioration of combustion state is detected, a microwave electric field is created in the combustion chamber prior to an opening timing of an exhaust valve at an end stage of the expansion stroke, thereby plasma is generated and enlarged in the combustion chamber.

A corona ignition system for maintaining a drive frequency approximately equal to the resonant frequency of a corona igniter is provided. The system includes a current sensor, at least two cascaded timers which are electrically independent of a controller, and at least two switches. During operation, the current sensor measures the current at an input of the corona igniter. A conditioned current signal including information related to the zero crossings of the current ultimately activates a pair of the timers which in turn control and drive one of the switches. The conditioned current signal is not processed by the controller before driving the switch.

An ignition coil for an internal combustion engine includes a primary bobbin including a winding cylinder part and a connection part between the winding cylinder part and a connector part, a primary coil including a primary main coil and a primary sub coil, and a secondary coil. When one of the primary main coil and the primary sub coil that includes an innermost coil part around the winding cylinder part is defined as a firstly-wound coil and the other is defined as a secondly-wound coil, firstly-wound ends, which are ends of the firstly-wound coil, and secondly-wound ends, which are ends of the secondly-wound coil, are attached to the connection part, and a shortest distance from a central axis of the winding cylinder part to each of the firstly-wound ends is smaller than a shortest distance from the central axis of the winding cylinder part to each of the secondly-wound ends.

In a general aspect, an ignition circuit can include a control circuit that is coupled with an engine control unit (ECU) to receive a command signal from the ECU. The control circuit can include a multi-pulse generator configured to, in response to the command signal, generate a multi-pulse drive signal. The multi-pulse drive signal can include a first pulse cycle having a first duty cycle, a second pulse cycle having a second duty cycle, and a dwell period during which the multi-pulse drive signal continuously remains at a logic high value. The control circuit can be configured to provide the multi-pulse drive signal to an ignition switch coupled with the control circuit to receive the multi-pulse drive signal.

An ignition device at least equipped with a DC power source, an ignition coil unit, a spark plug, an ignition switch, and an auxiliary power source, wherein the auxiliary power source is at least equipped with a discharge energy accumulating means, a discharge switch, and a discharge driver. The ignition device is further equipped with a secondary-current feedback controlling means comprising a secondary current detecting means for detecting a secondary current flowing during the ignition coil unit discharge period, and a secondary current feedback control circuit-for determining an upper limit and a lower limit for the secondary current from binary threshold values, and driving so as to open and close the discharge switch on the basis of the determination results. Furthermore, energy is introduced from the auxiliary power source without switching the polarity of the secondary current.