Abstract: A magneto-based, variable-timing ignition system for an internal combustion engine is provided that maintains at least one operating parameter of the engine within a predetermined limit. An electronic controller sets the timing of spark events based on engine performance criteria such as the temperature of the engine's cylinder head, speed and manifold pressure. If the values of one of these parameters, such as engine temperature, extends beyond a predetermine limit, the electronic controller retards the advance timing of the spark events to draw back within the limit the values of the parameter. The timing of spark events is ordinarily under electronic control. If the electronic control fails, the system provides spark events whose timing are fixed and synchronized to the mechanical rotation of the crankshaft of the engine.

Abstract: An ignition system exciter circuit includes a storage capacitor; a charging circuit for charging the capacitor; a discharge circuit connectable to an igniter plug; and a first switching circuit for controlling discharge of the capacitor through the discharge circuit and plug; the discharge circuit comprising a step-up transformer for transforming voltage stored on the capacitor to a higher voltage across the igniter plug when the first switching circuit is closed; the transformer having a primary winding and a secondary winding, with the secondary winding having a first terminal that can be coupled to a first terminal of the igniter plug and a second terminal that can be coupled to a second terminal of the igniter plug; and a second switching circuit that is responsive to a voltage transition across the igniter plug and that prevents the transformer primary and secondary windings from conducting spark discharge current.

Abstract: An ignition apparatus for a combustor includes a microwave energy source that emits microwave energy into the combustor, and a laser energy source that emits laser energy into the combustor so that a plasma is produced that ignites a combustible mixture therein. The plasma preferably is a non-contact plasma produced in free space within the combustor spaced away from with the combustor wall structure and spaced from the microwave emitter. In one embodiment, the microwave energy is emitted at a frequency within a resonant response of the combustor, and the laser energy is infrared laser energy.

Abstract: An apparatus for controllably generating sparks is provided. The apparatus includes a spark generating device; at least two output stages connected to the spark generating device; means for charging energy storage devices in the output stages and at least partially isolating each of the energy storage devices from the energy storage devices of the other output stages; and, a logic circuit for selectively triggering the output stages to generate a spark. Each of the output stages preferably includes: (1) an energy storage device to store the energy; (2) a controlled switch for selectively discharging the energy storage device; and (3) a network for transferring the energy discharged by the energy storage device to the spark generating device.

Abstract: A device for diagnosing the state of health of an ignition system is provided, where the system includes at least one spark producing channel comprising an exciter, output circuit and igniter plug. The device provides a diagnosis of the state of health for both the exciter and igniter plug by monitoring the high energy pulses at the output of the exciter. By monitoring the ignition system at an intermediate point in the system such as the output of the exciter, the sensor and electronics of the device may be completely contained within the electronic environment of the exciter, thereby avoiding any need for attaching sensors at the output of the system adjacent to the igniter plug in order to diagnose the plug's state of health. As an alternative to the device being built into the ignition system, it can be incorporated into automatic test equipment that produces high energy pulses for delivery to an igniter plug to be tested.

Abstract: A capacitative discharge device is provided as part of a magneto-based ignition system for enhancing the starting performance of the ignition system for an internal combustion engine. The ignition system incorporating the invention is applicable to conventional mechanically timed magnetos, including those intended to incorporate impulse coupling or inductive vibrators as starting aids. Although the ignition system incorporating the invention is primarily intended for aerospace applications, its relative small size the light weight make it also ideal for any type of portable application.

Abstract: An ignition system is provided for an internal combustion engine that operates in two modes. In a first mode, the timing of the spark event is under electronic control. In a second mode, the timing of the spark event is fixed and synchronized to the mechanical rotation of the crankshaft of the engine. Under normal operating conditions, the timing of the spark event is electronically controlled. If the electrical system of the engine malfunctions, the ignition system defaults to the second mode in which ignition timing is mechanically controlled.

Abstract: A device for diagnosing the state of health of an ignition system is provided, where the system includes at least one spark producing channel comprising an exciter, output circuit and igniter plug. The device provides a diagnosis of the state of health for both the exciter and igniter plug by monitoring the high energy pulses at the output of the exciter. By monitoring the ignition system at an intermediate point in the system such as the output of the exciter, the sensor and electronics of the device may be completely contained within the electronic environment of the exciter, thereby avoiding any need for attaching sensors at the output of the system adjacent to the igniter plug in order to diagnose the plug's state of health. As an alternative to the device being built into the ignition system, it can be incorporated into automatic test equipment that produces high energy pulses for delivery to an igniter plug to be tested.

Abstract: An apparatus and method extends the useful life of a low tension igniter plug by advancing a homogeneous semiconductor element as it is consumed over time by sparks between a central conductor and an outer metal shell of the plug. An insulator surrounds at least a portion of the central conductor, with the outer metal shell having a discharge end spaced to provide a spark gap with a tip of the central conductor. The homogeneous semiconductor element surrounds the tip of the central conductor and is axially positioned between the insulator and the discharge end of the outer metal shell so that it is in contact with the outer metal shell at the spark gap.

Abstract: A unipolar ignition of the invention provides a current waveform at the ignitor plug which initially rises relatively slowly, followed by a transition to a fast rising current which quickly peaks and thereafter slowly dissipates. Such a current waveform provides an initially hotter and longer lasting spark which does not harm the ignitor plug of the system or shorten its life expectancy. Neither does the spark create stress on the solid state circuitry which delivers the energy to the ignitor plug. To provide the foregoing spark and current characteristics, an inductor having a saturable core is in series with the ignitor plug, and it provides an initially high inductance which limits the rate of current rise at the plug as energy is transferred from an energy storage device to the plug. As the current through the inductor increases, its core begins to saturate and the effective inductance begins to decrease, allowing the current to rise more quickly.

Abstract: An ignition system is provided that marries a free-running discharge circuit with a fast-charging, high voltage converter without resulting in an excessive rate of discharge. To this end, the free-running discharge circuit employs a passive switch embodied either as a spark-gap device or a passive network of semiconductor elements. A feedback circuit detects discharge events at the discharge circuit and, in response thereto, selectively enables and disables the fast-charging converter. A spark rate clock is integrated into the feedback circuit for the purpose of setting the average discharge rate to a predetermined value.

Abstract: A device for diagnosing the state of health of an ignition system is provided, where the system includes at least one spark producing channel comprising an exciter, output circuit and igniter plug. The device provides a diagnosis of the state of health for both the exciter and igniter plug by monitoring the high energy pulses at the output of the exciter. By monitoring the ignition system at an intermediate point in the system such as the output of the exciter, the sensor and electronics of the device may be completely contained within the electronic environment of the exciter, thereby avoiding any need for attaching sensors at the output of the system adjacent to the igniter plug in order to diagnose the plug's state of health. As an alternative to the device being built into the ignition system, it can be incorporated into automatic test equipment that produces high energy pulses for delivery to an igniter plug to be tested.

Abstract: An exciter circuit for a gas turbine engine ignition system. A high voltage supply continuously charges a storage capacitor. A plurality of silicon controlled rectifiers (SCRs) are connected in series between the storage capacitor and a high voltage conditioning circuit. A multi-section protective network is connected in parallel with the series connected SCRs. Individual network sections are connected across separate ones of the SCRs. The SCRs are normally non-conducting and are periodically triggered to discharge the storage capacitor into the conditioning circuit. An igniter plug is connected to the output of the conditioning circuit. The protective network divides the voltage of the storage capacitor equally across the SCRs when the latter are non-conductive thereby reducing the voltage stress to which each of the SCRs is subjected.

Abstract: An igniter plug having a center conductor, an insulator and a conductive outer shell. The insulator surrounds and supports the center conductor axially within the shell along a substantial portion of the length of the center conductor. The insulator is of reduced diameter toward the discharge end of the igniter and terminates short of the full length of the center conductor. The center conductor extending beyond the insulator terminates short of the discharge end of the igniter and has a discharge electrode of greater diameter than the center conductor affixed to the center conductor end. The electrode terminates at the discharge end of the igniter. A helical compression spring is fitted over the center conductor between the end of the insulator and the electrode to absorb vibrations of the center conductor and electrode.