The invention relates to an improved ignition system for spark ignited combustion engines. According to the invention the voltage over a coil winding 6P on the primary side of the ignition coil is regulated to a sufficiently low voltage level during timed periods of the ignition cycle, such that at least one function out of three in total, i.e. prevention of premature spark-on-make, or spark suppression after onset of ignition, or improved frequency response between primary and secondary side of the ignition coil after end of ignition, is obtained. When applied in an inductive ignition system a differential amplifier (8) may be connected over the primary winding 6P regulating a control switch 2CS via a drive unit (9). The invention is preferably implemented in ignition systems with ion sense circuitry 5C,5R on the secondary side of the ignition coil, and implementing all three functions.

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 method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; 5 ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are 10 retrieved and used in combination.

A spark plug combustion ionization sensor for measuring ion current inside the cylinder of an internal combustion engine. The sensor measures ion current which flows when the energy released during combustion ionizes the air inside the cylinder, and thus can detect combustion and emission parameters. The spark plug combustion ionization sensor generally includes an insulated, dedicated sensing electrode, separate from the sparking electrode of a spark plug. The sensing electrode may also be shielded to further reduce interference such as electromagnetic interference (EMI). The use of a dedicated electrode allows for ion current measurement with less electromagnetic noise from the ignition process, and also eliminates the need for circuitry that is typically necessary when the sparking electrode is also used to sense ion current.

A method for ignition control in a combustion chamber of an internal combustion engine by means of acquiring an electric signal relating to ionizing currents emitted in said combustion chamber, comprising a step of detecting a substantially stepped trend of said electric signal and a consequent step of inhibiting a corrective action of an ignition advance and/or of a fuel injection limitation curve in the combustion chamber.

The invention provides an internal combustion engine combustion state detecting device such that ascertaining a combustion state using ionic current detection is carried out accurately over a wide operating range of an internal combustion engine. The internal combustion engine combustion state detecting device includes a spark plug that has a central electrode and a grounding electrode opposing across a gap, and a discharge stopping-induced current detecting device that estimates an induced current caused by a stopping of a spark discharge generated in the gap between the central electrode and the grounding electrode, wherein an ionic current detection threshold is set to a threshold value that is not affected by the induced current using the induced current estimated by the discharge stopping-induced current detecting device.

An ignition device according to the present invention includes: an ignition plug, which includes a first electrode, a second electrode, and a dielectric body arranged between the electrodes; an AC power supply configured to generate an AC voltage to be applied between the electrodes; a thermal plasma detection portion configured to output a thermal plasma occurrence signal when thermal plasma has occurred between the electrodes; and an application time period determination portion configured to determine an application time period for the AC voltage during one cycle of the internal combustion engine in advance before the application, and when the thermal plasma occurrence signal is received while the AC voltage is being applied based on the application time period, change the application time period so as to shorten the application time period.

To provide a control device, of an internal combustion engine, that accurately identifies the combustion state through ion current detection in a wide operation range of the internal combustion engine, without impairing the reliability and the durability of the control device of the internal combustion engine. This internal combustion engine control device includes: an ignition plug having a center electrode and a ground electrode opposed to each other with a gap therebetween; a circulation device for short-circuiting a primary winding to cause a circulation route to enter a conduction state, thereby stopping spark discharge; and an ion-current-detection bias voltage control device for controlling bias voltage for ion current detection. The potential of the center electrode in an ion current detection period is controlled by adjusting the value of the bias voltage and the changing speed of the bias voltage.

Please substitute the new Abstract submitted herewith for the original Abstract: Energization abnormality of a switch element of an internal combustion engine ignition device is detected appropriately. To this end, in an internal combustion engine ignition device that includes an ignition coil and an ignition plug, the ignition coil includes a primary coil including a main primary coil and a sub primary coil and a secondary coil that generates secondary current in response to a voltage variation generated in the primary coil. The internal combustion engine ignition device includes a main switch element that performs energization/deenergization of the main primary coil in a first direction, a sub primary coil magnetic flux generation state switching unit capable of switching between a forward direction magnetic flux generation state in which energization of the sub primary coil in the first direction is performed and an opposite direction magnetic flux generation state in which energization of the sub primary coil in a second direction is performed, and an abnormality detection section that detects energization abnormality to the sub primary coil. The abnormality detection section is configured so as to detect energization abnormality on the basis of overlap between energization in the first direction and energization in the second direction of the sub primary coil.

A system and method to enable electronically controlled internal combustion engines to self-adjust parameters and operate properly on different fuels that have wide ranges of physical and chemical properties. Input from a sensor is utilized that gives a signal indicative of the combustion process. The ECU processes the signal and readjusts the engine operating parameters to achieve its operating goals.