Abstract: A reversed-assembled corona igniter including an insulator, central electrode, and metal shell, wherein an outer diameter of the insulator increases adjacent a lower end of the metal shell to achieve an electrical advantage is provided. In addition, the insulator maintains strength because is not placed under tension during or after assembly, or once disposed in an engine. To achieve the increase in insulator outer diameter, the insulator includes a lower shoulder adjacent the shell firing end. An intermediate part, such as braze and/or a metal ring, is disposed between the insulator outer surface and the shell adjacent the shell firing end. To prevent tension in the insulator, the insulator can be supported at only one location between the insulator upper end and the insulator lower end, for example along the intermediate part.

Abstract: A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

Abstract: 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.

Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: A corona igniter (20) comprises a central electrode (22) surrounded by an insulator (26), which is surrounded by a conductive component. The conductive component includes a shell (34) and an intermediate part (36) both formed of an electrically conductive material. An outer surface (50) of the insulator (26) presents a lower ledge (52), and the intermediate part (36) is typically attached to the insulator (26) above the lower ledge (52) prior to inserting the insulator (26) into the shell (34). The conductive inner diameter (Dg) is less than an insulator outer diameter (Dio) directly below the lower ledge (52) such the insulator thickness (ti) increases toward the electrode firing end (40). The corona igniter (20) can be reversed-assembled by inserting an upper end (42) of the insulator into a firing end (56) of the shell.

Abstract: The invention provides a system and method for controlling corona discharge and arc formations during a single corona event, i.e. intra-event control. A driver circuit provides energy to the corona igniter and detects any arc formation. In response to each arc formation, the energy provided to the corona igniter is shut off for short time. The driver circuit also obtains information about the arc formations, such as timing of the first arc formation and number of occurrences. A control unit then adjusts the energy provided to the corona igniter after the shut off time and during the same corona event based on the information about the arc formations. For example, the voltage level could be reduced or the shut-off time could be increased to limit arc formations and increase the size of the corona discharge during the same corona event.

Abstract: A system and method for detecting resonant frequency of a corona igniter concurrent with operation of the corona igniter is provided. The method includes providing a plurality of pulses of energy to the corona igniter, each having a pulse duration and spaced from one another by a deadtime duration during which no energy is provided to the corona igniter. Each pulse duration is ceased before current flowing in the corona igniter crosses zero, and each zero crossing of the current occurs during one of the deadtime durations. The next pulse of energy is provided to the corona igniter in response to the zero crossing of the current. A resonant frequency value is then obtained based on a sum of the pulse and deadtime durations of two consecutive cycles, or the time between zero crossings. The resonant frequency values become more accurate over time, and the drive frequency is adjusted accordingly.

Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: A corona ignition system including a corona igniter, an energy supply, and a frequency detector is provided. The energy supply provides energy to the corona igniter during corona events which are spaced from one another by idle periods, during which no energy is provided to the corona igniter. During the idle periods, the frequency detector obtains the resonant frequency of the corona igniter from at least one of an output voltage and an output current of the energy stored in the corona igniter. The resonant frequency measured during this idle period is dependent only on the corona igniter, and not any other components of the system, and thus is very accurate. The drive frequency of future corona events can then be set based on this accurately measured resonant frequency to achieve a robust corona discharge.

Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: The invention provides a system and method for controlling corona discharge and arc formations during a single corona event, i.e. intra-event control. A driver circuit provides energy to the corona igniter and detects any arc formation. In response to each arc formation, the energy provided to the corona igniter is shut off for short time. The driver circuit also obtains information about the arc formations, such as timing of the first arc formation and number of occurrences. A control unit then adjusts the energy provided to the corona igniter after the shut off time and during the same corona event based on the information about the arc formations. For example, the voltage level could be reduced or the shut-off time could be increased to limit arc formations and increase the size of the corona discharge during the same corona event.

Abstract: A corona discharge ignition system comprising a plurality of corona igniters is provided. The system includes a control and drive electronics unit for directing the energy from a power supply toward the corona igniters; and a single transformer disposed between the control and drive electronics unit and the plurality of corona igniters. A plurality of igniter switching units is connected to the control and drive electronics unit and each igniter switching unit is connected to a separate one of the corona igniters. Each igniter switching unit allows current to travel from the transformer to the one connected corona igniter when activated and prevents current from traveling from the transformer to the one connected corona igniter and from the one connected corona igniter toward the transformer when deactivated. Only one of the igniter switching units is activated at any given time during operation of the system.

Abstract: A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

Abstract: A reversed-assembled corona igniter including an insulator, central electrode, and metal shell, wherein an outer diameter of the insulator increases adjacent a lower end of the metal shell to achieve an electrical advantage is provided. In addition, the insulator maintains strength because is not placed under tension during or after assembly, or once disposed in an engine. To achieve the increase in insulator outer diameter, the insulator includes a lower shoulder adjacent the shell firing end. An intermediate part, such as braze and/or a metal ring, is disposed between the insulator outer surface and the shell adjacent the shell firing end. To prevent tension in the insulator, the insulator can be supported at only one location between the insulator upper end and the insulator lower end, for example along the intermediate part.

Abstract: A power amplifier circuit for a corona ignition system is provided. The circuit includes an inductor and capacitor connected to one end of a secondary winding of an RF transformer. The other end of the secondary winding is connected to a current sensor which is connected to ground. The transformer also has a primary winding with one end connected to a voltage supply and the other end attached to a pair of switches. The windings are wound around a core. Current flowing from the DC voltage supply to the switches causes a magnetic flux in the core. A voltage is generated on the secondary winding by the current that flows through the igniter. This voltage is fed back to the switches, controlling on and off timing. Voltage is provided to the corona igniter or pulled from the igniter when the current traveling into or from the igniter is at zero.

Abstract: The invention provides a system and method for controlling corona discharge and arc formations during a single corona event, i.e. intra-event control. A driver circuit provides energy to the corona igniter and detects any arc formation. In response to each arc formation, the energy provided to the corona igniter is shut off for short time. The driver circuit also obtains information about the arc formations, such as timing of the first arc formation and number of occurrences. A control unit then adjusts the energy provided to the corona igniter after the shut off time and during the same corona event based on the information about the arc formations. For example, the voltage level could be reduced or the shut-off time could be increased to limit arc formations and increase the size of the corona discharge during the same corona event.

Abstract: A power amplifier circuit that has an inductor and capacitor connected to one end of the output winding of an RF transformer. The other end of the output winding is connected to a current sensor that in turn is connected to ground. The transformer has two primary windings. Both primary windings have one end connected to a voltage supply. The other end of each primary winding is attached to a switch. All three windings are wound around a core. Current flowing from the DC voltage supply to the switches causes a magnetic flux in the core. A voltage is generated on the secondary winding current sensor by the current that flows through the igniter. This voltage is fed back to the switches, controlling on and off timing. Voltage is provided to the igniter or pulled from the igniter when the current traveling into or from the igniter is at zero.

Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: A system and method for detecting arc formation in a corona discharge ignition system is provided. The system includes a driver circuit conveying energy oscillating at a resonant frequency; a corona igniter for receiving the energy and providing a corona discharge; and a frequency monitor for identifying a variation in an oscillation period of the resonant frequency, wherein the variation in the oscillation period indicates the onset of arc formation. The method includes supplying the energy to the driver circuit and to the corona igniter; obtaining the resonant frequency of the energy in the oscillating driver circuit; and identifying a variation in the oscillation period of the resonant frequency.