Permanent magnet ignition device and ignition system for piston type engine of aircraft

Abstract

An aircraft piston engine permanent magnet ignition device has a magnetic rotor and an ignition circuit having a reconfigurable charging coil inductively coupled to the magnetic rotor. The charging coil includes a plurality of coils inductively powered by the magnetic rotor and electronically reconfigurable from a higher number of turns, lower amperage power coil used in low speed operation to a lower number of turns, higher amperage coil used in high speed operation. The charging coil is configured as a coil of a higher number of turns by electrically connecting a plurality of coils in series, and is configured as a power coil of a lower number of turns by electrically connecting a plurality of coils in parallel. The ignition circuit is a full-electronic ignition circuit that uses only non-mechanically actuated electrical components within the permanent magnet ignition device to generate and distribute ignition pulses to the piston engine spark plugs.

Description

Technical Field

[0001] The invention relates to an ignition system of a permanent magnet ignition device for an aircraft piston engine. Background Art

[0002] A typical permanent magnet ignition system for an aircraft piston engine includes all the mechanical and electrical components required to generate and time the ignition pulse to the spark plug via the ignition lead. A significant advantage of a permanent magnet ignition system is that once the engine is started, the ignition system can operate without requiring any batteries or other external power source for the permanent magnet ignition system.

[0003] As schematically shown in Figure 12, most magnetos in use today have a permanent magnet rotor (also called a magnetic rotor) driven by an external input that rotates synchronously with and at the same speed as the engine crankshaft; a primary coil that stores energy from the rotor's changing magnetic flux during rotation; a secondary coil inductively coupled to the primary coil to provide a high voltage boost when the current through the primary coil is interrupted, causing a contact breaker that interrupts the primary current; a camshaft with a cam that mechanically opens and closes the contact breaker in synchronization with the crankshaft's angular position; and a distributor with rotating switch terminals connected to the secondary coil to sequentially distribute the ignition pulses to the spark plugs in the different cylinders. Both the camshaft and the distributor switch are rotated by the rotor, so that the mechanical rotation of the input driving the permanent magnet ignition device is transmitted through the rotor to the camshaft and the distributor switch. This can be seen in Figures 13 and 14 of a typical permanent magnet ignition device. The camshaft is formed by the end of the rotor opposite its input end and includes a slot into which a cam is press-fitted and axially positioned to engage the movable breaker point of the contact breaker. The distributor's rotary switch operates via meshing gears, including a distributor drive gear assembled on the camshaft above the cam and a driven gear that mounts the rotary switch in the distributor. This mechanically operated permanent magnet ignition device, which includes at least a cam-driven contact breaker and a distributor, is referred to herein as a mechanical permanent magnet ignition device.

[0004] To achieve proper timing of the spark in each cylinder, the angular position of the rotor's magnetic poles must be set relative to the crankshaft's cylinder TDC. Once set, the angular position of the magnetic poles is maintained by gearing from the crankshaft, which also maintains the distributor's rotary switch. However, in mechanical permanent magnet ignition systems, physical wear on components from use can affect the actual timing of the ignition pulse relative to TDC, particularly the cam and its contact breaker. As a result, this timing is typically checked and, if necessary, recalibrated to TDC every 100 hours of operation, with internal inspections of the permanent magnet ignition system and replacement of worn parts occurring every 500 hours. These checks and inspections increase the repair and maintenance burden on aircraft engines, as they are much shorter than the typical 2,000-hour engine overhaul schedule.

[0005] In addition to calibrating the rotor angular position relative to TDC, basic adjustment of the ignition timing is also required. Unlike more complex internal combustion engines used in the automotive industry, the spark timing in permanent magnet ignition type aircraft piston engines is typically fixed (and not variable) relative to the piston top dead center (TDC). For maximum efficiency at normal flight operating speeds, the fixed timing is set at approximately 20° before TDC (BTDC). However, at lower starting speeds, this is too early in the cycle and causes cylinder ignition to occur during the compression stroke before TDC is reached. Therefore, for slower engine speeds (e.g., <600 rpm), many magnets include an impulse coupling connected between the permanent magnet rotor and its input drive. The impulse coupling includes one or more pawls designed to stop and release contact with a stop pin as the coupling rotates. This results in one or more pauses in the rotor's rotation during each rotation, while loading a coil spring that is released at the end of each pause to provide high-speed rotation return of the rotor. In this way, after a pause, the rotor accelerates and catches up with the input drive, thereby generating sufficient flux in the permanent magnet ignition device to ignite the spark plug. These rotational pauses are generated by interference contact between one or more pawls of the impulse coupling and at least one stop pin on the permanent magnet ignition device housing. At higher speeds, the impulse coupling pawls move out of their functional position due to the centripetal force on them. This allows the rotor to run continuously at the same speed as the input drive. The input coupling is another mechanical component that is subject to wear and must be inspected (and replaced if necessary) several times between normal 2000-hour engine overhauls.

[0006] Delayed contact breakers are used on some mechanical permanent magnet ignition devices instead of pulse couplings. Although they have the advantage of reducing the mechanical wear problem of the pulse coupling, they only solve the ignition timing problem at slower engine speeds and do not help the permanent magnet ignition device to generate enough power to operate the ignition. Therefore, they require aircraft battery power and a starter vibrator to generate a pulse from the battery power, which is fed to the permanent magnet ignition device primary coil via the P- lead of the pilot. Because they require external power input to operate, such delayed breaker permanent magnet ignition devices are not electrically self-starting and have the same cam, camshaft, contact breaker (set of 2) and distributor mechanical problems as other conventional permanent magnet ignition devices. Summary of the Invention

[0007] According to one aspect of the present invention, a permanent magnet ignition device for an aircraft piston engine is provided. The device comprises a magnetic rotor and an ignition circuit, wherein the ignition circuit includes a charging coil inductively coupled to a magnetic pole of the rotor, wherein the charging coil includes a plurality of power coils that can be electronically reconfigured by the ignition circuit between a series connection and a parallel connection of the power coils. In at least some embodiments, the permanent magnet ignition device comprises a fully electronic permanent magnet ignition device that generates and outputs ignition pulses using an ignition circuit that includes only non-mechanically actuated electrical components. The ignition circuit may include a position sensor positioned adjacent to at least one magnet carried by the rotor, wherein the ignition circuit derives power and data solely from the rotating magnetic field generated by the rotor during rotation.

[0008] According to another aspect of the present invention, a permanent magnet ignition device for an aircraft piston engine is provided having a magnetic rotor and an ignition circuit. The ignition circuit includes a reconfigurable charging coil inductively coupled to the magnetic poles of the rotor. The reconfigurable charging coil includes a plurality of coils that are inductively switched off from the magnetic rotor and electronically reconfigurable from a higher-turns, lower-amperage power coil for use during low-speed operation to a lower-turns, higher-amperage power coil for use during high-speed operation. In at least some embodiments, the charging coil is configured as the higher-turns, lower-amperage power coil by electrically connecting the plurality of coils in series, and as the lower-turns, higher-amperage power coil by electrically connecting the plurality of coils in parallel. The ignition circuit may include a speed detector that detects whether the magnetic rotor indicates an engine speed above or below a speed threshold when rotating. When the speed detector indicates the engine speed is below the speed threshold, the ignition circuit may configure the plurality of coils in series connection, and when the speed detector indicates the engine speed is above the speed threshold, the ignition circuit may configure the charging coils in parallel connection. The ignition circuit may comprise only non-mechanically actuated electrical components, whereby the permanent magnet ignition device comprises a fully electronic permanent magnet ignition device, and the ignition circuit may comprise a position sensor positioned adjacent to at least one magnet carried by the rotor, wherein the ignition circuit derives power and data solely from the rotating magnetic field generated by the rotor during rotation.

[0009] According to yet another aspect of the present invention, a permanent magnet ignition device is provided, comprising: a housing; a rotor assembly mounted in the housing and including a magnetic rotor and at least one bearing, the at least one bearing supporting the rotor for rotation within the housing, the rotor assembly having a first end and a second end, wherein the rotor has a permanent magnet assembly positioned between the first end and the second end, wherein the first end is externally accessible at an opening in the housing so that the rotor can be rotationally driven by an external drive component; and an ignition circuit comprising circuit components including at least one power coil and a position sensor, each inductively coupled to the magnetic rotor, the ignition circuit including a high-voltage output terminal mounted at an externally accessible location within the housing. The rotor assembly is a terminal mechanical device, allowing the rotor to rotate within the housing without transmitting its mechanical motion to any circuit components. In at least some embodiments, the ignition circuit is a fully electronic ignition circuit that uses only non-mechanically actuated electrical components within the permanent magnet ignition device to generate and distribute ignition pulses to the output terminals. The ignition circuit may include a plurality of power coils that are electronically reconfigurable by the ignition circuit between a series connection and a parallel connection of the power coils.

[0010] According to yet another aspect of the present invention, there is provided a piston engine ignition system mechanically powered by a single magnetic rotor and having a plurality of high-voltage output terminals adapted for connection to ignition leads for supplying ignition energy to one or more spark plugs via the ignition leads, the ignition system including a fully electronic ignition circuit operating on power provided solely by induction from the magnetic rotor, wherein the ignition circuit generates ignition energy from the received power and selectively distributes the ignition energy as high-voltage ignition pulses to the output terminals, and wherein the ignition circuit includes a position sensor for detecting the rotational angle of the magnetic rotor and further includes control logic for controlling the timing of the ignition pulses relative to the rotational angle of the magnetic rotor according to rotor speed based on rotational angle data from the position sensor.

[0011] The permanent magnetic ignition device may include any of the following features or any technically feasible combination of the following features:

[0012] - the control logic further includes a speed detector that changes the ignition timing of the ignition pulses depending on whether the rotor speed is above a predetermined speed or below a predetermined speed;

[0013] - a speed detector including timing and logic circuitry that controls the advancement and retardation of spark timing relative to the output of a position sensor indicating that the engine piston is at top dead center (TDC);

[0014] - the speed detector sets the ignition timing to a first trigger angle when the rotor speed is within a range from about 100 rpm up to a predetermined speed, and advances the ignition timing to a second trigger angle that is ahead of the first trigger angle when the rotor speed is above the predetermined speed;

[0015] - the first trigger angle is about 0-10° after TDC, and the second trigger angle is about 18°-28° before TDC, and wherein the predetermined speed is in the range of 250 rpm-600 rpm;

[0016] - the position sensor is a magnetoresistive sensor that outputs rotational angle data as a quadrature sinusoidal waveform indicative of the rotational angle of the magnetic rotor, and wherein the control circuit includes logic circuitry capable of triggering ignition pulses using the sinusoidal waveform only during certain rotational angles of the rotor;

[0017] an ignition circuit comprising a plurality of power coils positioned adjacent the magnetic rotor at a first angular position such that the power coils provide power to operate the ignition circuit, and wherein a position sensor is positioned adjacent the magnetic rotor at a second angular position such that the position sensor senses magnetic field lines of the magnetic rotor as the rotor rotates;

[0018] The charging coil includes a plurality of power coils that can be electronically reconfigured between a series connection and a parallel connection of the power coils by means of an ignition circuit.

[0019] According to another aspect of the present invention, a permanent magnet ignition device is provided, comprising: a permanent magnet rotor; a ferromagnetic core positioned relative to the rotor, the ferromagnetic core for concentrating and directing changing magnetic field lines extending between opposing magnetic poles of the rotor as the rotor rotates; and an ignition circuit for inductively extracting power from the changing magnetic field lines, wherein the ignition circuit comprises: a power circuit having a reconfigurable charging coil comprising a plurality of power coils wound around the core and supplying inductive power to one or more output nodes of the power circuit; a high-voltage discharge circuit connected to the output nodes of the power circuit and generating high-voltage spark energy at a plurality of high-voltage output terminals; and a control circuit connected to at least one output node of the power circuit and operable under power from the at least one output node of the power circuit, wherein the control circuit comprises control outputs connected to both the power circuit and the discharge circuit, the control outputs comprising at least one control output to the power circuit that electronically configures the power coils in series or parallel, and at least another control output connected to the discharge circuit that induces a high-voltage ignition pulse suitable for triggering a spark plug.

[0020] According to yet another aspect of the present invention, a permanent magnet ignition device is provided, the permanent magnet ignition device comprising: a permanent magnet rotor; a ferromagnetic core positioned relative to the rotor, the ferromagnetic core concentrating and guiding changing magnetic field lines, the magnetic field lines extending between opposite magnetic poles of the rotor as the rotor rotates; and an ignition circuit that inductively extracts power from the changing magnetic field lines, wherein the ignition circuit comprises:

[0021] a power circuit having a plurality of power coils wound around the core and supplying inductive power to one or more output nodes of the power circuit;

[0022] a capacitive discharge ignition (CDI) discharge circuit having at least one ignition storage capacitor charged via one or more output nodes, at least one ignition coil configured as a step-up transformer, and at least one controllable solid-state switch, the step-up transformer having a primary coil connected to one or more outputs of the CDI discharge circuit and an inductively coupled secondary coil, wherein the solid-state switch and the primary coil are connected in series across the ignition storage capacitor such that upon activation of the solid-state switch, charge from the ignition storage capacitor flows through the switch and the primary coil, thereby establishing a magnetic field that is maintained until the solid-state switch is deactivated, at which time current flow through the primary coil is interrupted to induce a high voltage pulse across the secondary coil; and

[0023] a control circuit including at least one operating power storage capacitor; a position sensor positioned adjacent the magnetic rotor to detect magnetic field lines emanating from the rotor as the rotor rotates; and a timing circuit to control operation of the solid-state switch based on an angular position of the rotor sensed by the position sensor,

[0024] The operating power storage capacitor of the control circuit is connected to the ignition storage capacitor via a diode. The diode allows charging of the operating power storage capacitor and prevents it from discharging to the ignition storage capacitor through reverse current, so that the power coil provides operating power for both the ignition circuit and the control circuit.

[0025] In at least some embodiments, the control circuit includes at least two DC voltage regulators connected to receive input power from an operating power storage capacitor and output two different DC voltages for operation of the logic circuit. The plurality of power coils can be electronically reconfigured between series and parallel connections of the power coils via the ignition circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Preferred exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0027] Figure 1 A partial perspective view of a four-cylinder aircraft piston engine having a left permanent magnet ignition device constructed in accordance with an embodiment of the present invention is shown, and is shown in a partially exploded view;

[0028] Figure 2 is used for Figure 1 An exploded view of the rotor assembly in the left permanent magnet ignition device;

[0029] Figure 3 is a three-dimensional diagram of the housing of the permanent magnet ignition device;

[0030] Figure 4 is a fragmentary perspective view of a portion of a housing and a rotor assembly connected to a piston engine;

[0031] Figure 5A An embodiment of a rotor assembly, a position sensor, and a power coil for realizing a fully electronic permanent magnet ignition device is schematically depicted;

[0032] Figure 5B Another embodiment of a rotor assembly, a position sensor, and a power coil for realizing a fully electronic permanent magnet ignition device is schematically depicted;

[0033] Figure 6is a block diagram of an ignition circuit for a fully electronic permanent magnet ignition device constructed in accordance with an embodiment of the present invention as it would be electrically connected to four spark plugs of a four-cylinder aircraft piston engine;

[0034] Figure 7 yes Figure 6 Schematic diagram of the energy storage capacitor circuit of the ignition circuit;

[0035] Figure 8 yes Figure 6 Electrical schematic diagram of the power circuit of the ignition circuit;

[0036] Figures 8A-8D Shown Figure 8 The power circuit comprises multiple parts, each part including a functional sub-circuit, wherein Figure 8A Depicts the low speed starting circuit, Figure 8B It is a normal mode circuit. Figure 8C is the shutdown circuit, and Figure 8D It is an overvoltage protection circuit;

[0037] Figure 9 and Figure 10 It was depicted together Figure 6 Electrical schematic diagram of the control circuit;

[0038] Figure 11 is a graph illustrating quadrature sinusoidal outputs of a position sensor during operation of a permanent magnet ignition device and depicting different regions and set points for achieving ignition timing with a fully electronic permanent magnet ignition device; and

[0039] 12-14 depict a prior art mechanical permanent magnet ignition device using a contact breaker and a rotary switch distributor to power the spark plugs of a piston aircraft engine. DETAILED DESCRIPTION

[0040] exist Figure 1 , a portion of a four-cylinder aircraft piston engine 20 is shown, including the engine's auxiliary housing 22, to which a pair of left and right fully electronic permanent magnet ignition devices 24 and 26, constructed in accordance with an embodiment of the present invention, are secured. These two permanent magnet ignition devices can be identical and provided for redundancy, with the left permanent magnet ignition device 24 actuating the upper spark plug in each of the four cylinders, and the right permanent magnet ignition device 26 actuating the lower spark plug in each of these same cylinders. In this manner, all cylinders can be operated by either or both of the two permanent magnet ignition devices. The construction and operation of the left permanent magnet ignition device 24 will be described below, with the understanding that the construction and operation of the right permanent magnet ignition device 26 can be identical.

[0041] Generally speaking, the permanent magnetic ignition device 24 shown and described below includes three main components or subassemblies: a housing 30, a magnetic rotor assembly 50 ( Figure 2 ) and ignition circuit 64 ( Figure 6 Unlike a mechanical permanent magnet ignition device, the rotor 52 of the rotor assembly 50 is not used to actuate additional mechanical components in the internal ignition circuit. Instead, the angular position sensor 66 ( Figure 5A 、 Figure 5B 、 Figure 6 as well as Figure 9 ) is used in conjunction with the rotating rotor 52 to determine the rotor angle and electronically generate the desired ignition timing to properly fire the engine spark plugs. As will be described below, this all-electronic permanent magnet ignition device construction is made possible by the use of a reconfigurable charging coil arrangement including multiple coils that are inductively powered by the magnetic rotor 52 and can be electronically configured from a higher turn, lower amperage power coil for low speed operation to a higher turn, lower amperage power coil for high speed operation. This allows the permanent magnet ignition device 24 to generate sufficient spark voltage to produce ignition energy even at low speeds without any external power connection and without any pulse coupling or other mechanical methods. In the following description, the permanent magnet ignition device housing 30, rotor assembly 50, power extraction, and rotor position sensing will be described, followed by the ignition circuit 64.

[0042] The permanent magnet ignition device housing 30 holds and provides a sealed enclosure for the rotor assembly 50 and the ignition circuit 64. Figure 3 and Figure 4 As shown, the housing 30 can be a two-piece housing having a lower frame 31 and an upper cover 32, and the upper cover 32 can be fastened to the frame 31 along a parting line 33. For this purpose, removable fasteners (such as screws or bolts, etc.) or permanent fasteners (such as rivets, etc.) can be used. The housing 30 has an opening 34 in its lower frame 31, through which the rotor 52 can be connected to the engine 20 using a Woodruff key 35, a flat piece or other device for locking the rotation of the rotor 52 to whatever component (the driving component is used to mechanically power it). The housing 30 further includes four high voltage output terminals 36 mounted at an externally accessible position on the upper cover 32, to which ignition leads can be connected to transmit ignition pulses from the permanent magnet ignition device 24 to the spark plug (in Figure 6 Schematically shown in FIG). The ignition leads and spark plugs may be conventional or of other types.

[0043] Return Reference Figure 1The components of the mounting interface of the left permanent magnet ignition device 24 to the engine 20 are shown in exploded view and include an adapter 37 and a gasket 38 to seal the opening 34 in the permanent magnet ignition device housing to a corresponding opening 39 in the engine auxiliary housing 22. The interface also includes an external drive component 40 in the form of an external gear having an integral hub 41 having a drive slot 42 slotted on its front axial face for transmitting rotational motion to the input coupling 51 ( Figure 2 Although the external drive gear 40 is mounted on the input end of the rotor 52, it is referred to as external because it is not part of the permanent magnet ignition system, but is actually located within the engine auxiliary housing 22 during use. The drive gear 40 meshes with an upstream gear in the engine, which is driven directly or indirectly away from the crankshaft using a gear ratio that causes the external drive gear to rotate at the same rate as the crankshaft. Therefore, the rotation angle of the external drive gear matches the rotation angle of the crankshaft position. Figure 2 A mechanical input coupling 51 is shown that can be rigidly attached to the rotor 52 for rotation therewith. The input coupling includes a drive lug 53 that is keyed to mate with the drive slot 42 of the external drive gear 40 to provide positive driving engagement of the input coupling 51. In this way, the rotor 52 is directly driven by the external drive gear 40 so that the rotation of the rotor is locked to the rotation of the engine crankshaft.

[0044] This type of drive lug / slot coupling for transmitting drive power to the rotor 52 is typical for mechanical permanent magnet ignition devices because it enables the use of impulse couplings for which the rotor is not locked to an external drive component but is driven via a lug-coupled coupling housing, and also allows non-pulse coupling permanent magnet ignition devices to utilize the same slotted external drive component using a simple lug input coupling locked to the rotor, such as Figure 2 However, for the fully electronic permanent magnet ignition device 24 described herein, other simpler drive connections may be used, such as by securing the external drive gear 40 to the rotor 52 in a locking manner that does not allow relative rotation between the external drive gear 40 and the rotor 52. This provides a more direct drive of the permanent magnet ignition device rotor using fewer components.

[0045] The rotor 52 comprises a portion of a rotor assembly 50 which also includes at least one bearing, but typically includes both an inner bearing 54 and an outer bearing 55 as shown. These bearings 54, 55 are used to rotatably mount the rotor 52 within the permanent magnet ignition device housing 30. The rotor 52 includes a mechanical input coupling 51 with a lug (from Figure 2The other components are shown in reverse perspective view). The rotor 52 extends from a first end 56 to a second end 57 and includes a permanent magnet assembly 58 at a position between the first end 56 and the second end 57. The permanent magnet assembly 58 can be one or more magnets 59 in a conventional or unconventional arrangement, with the one or more magnets 59 presenting one or more pairs of strong magnetic poles facing radially outward. These magnets 59 are referred to herein as power magnets because they are used in conjunction with the charging coil of the ignition circuit 64 to generate the power required to operate and fire the spark plug. The rotor 52 further includes a sensor magnet 60 that is mounted in a radial slot 61 located in the second end of the rotor 52. The angular position sensor 66 itself is mounted to the housing 30 at a position adjacent to and facing the magnet 60, as combined Figure 5A and Figure 5B As shown and described.

[0046] The rotor assembly 50 does not include an impulse coupling, a delay breaker, a camshaft, a cam, or a distributor drive gear. Therefore, it is much simpler in design and construction than those used in mechanical permanent magnet ignition devices. Furthermore, given that the rotor assembly does not drive the movement of any other components in the permanent magnet ignition device 24, it constitutes a "terminal mechanical device." As used herein, a "terminal mechanical device" refers to a device that moves when mechanically driven without transmitting any motion to another device. In other words, the rotor 52 rotates without any mechanical load, and those skilled in the art will understand that the bearings 54 and 55 holding the rotor 52 are not considered mechanical loads. The rotor assembly 50 is the last in a chain of mechanical drive components, which in this case also include, in the order driven, a crankshaft, an internal engine gear connected to an external drive component in the auxiliary housing 22, and the mechanical input coupling 51 of the rotor assembly 50.

[0047] The elimination of the pulse coupling, delay circuit breaker, camshaft, cam, contactor circuit breaker, and distributor is achieved by an innovative ignition circuit design that (i) operates solely on electricity generated within the permanent magnet ignition device 24, and (ii) includes an electronically reconfigurable charging coil 65 ( Figure 5Aand below), the charging coil 65 produces sufficient magneto power at both low (starting) engine speeds and full engine speeds, and (iii) is "all electronic," meaning that the ignition circuit 64 utilizes only non-mechanically actuated electrical components within the permanent magnet ignition device 24 to generate and distribute the ignition pulses. The all-electronic ignition circuit 64 with its reconfigurable charging coil 65 allows the ignition circuit to: once the engine is started by the starter motor, or even by appropriate manual rotation of the propeller, ignition through the permanent magnet ignition device 24 can begin even at engine speeds of about 100 rpm or less, and can be sustained throughout the entire engine speed range. And this all-electronic permanent magnet ignition device 24 takes advantage of the fact that the mechanically actuated circuit components in the mechanical permanent magnet ignition device are all functionally associated with the need to control the timing and distribution of the ignition pulses. In the embodiment shown, the ignition timing function uses a single angular position sensor 66 ( Figure 5A 、 Figure 5B 、 Figure 6 as well as Figure 9 ) is implemented electronically to detect the instantaneous angular position of the rotor, and therefore the instantaneous angular position of the engine crankshaft. As will be described below, the distribution of ignition pulses to cylinders is achieved electronically using multiple ignition channels, each with its own ignition coil.

[0048] In general, the position sensor 66 can be any suitable angle sensor that outputs rotational angle data with sufficient accuracy and resolution for use by the ignition circuit 64 to provide speed detection and proper ignition timing, whether fixed, continuously variable, or variable between two or more speed ranges. To this end, the sensor 66 should be a sensor that resolves the rotor angular position with sufficient accuracy and resolution for use by the ignition circuit 64 in correctly timing the ignition pulse. In the illustrated embodiment, the position sensor 66 is a reluctance sensor that provides a quadrature sinusoidal signal that the ignition circuit 64 uses to resolve the angular position of the rotor 52, and thus the position of the engine piston relative to its TDC. An example reluctance sensor that can be used is the commercially available TLE5501 TMR-based angle sensor. Depending on the specific magneto application, optical and other non-magnetic angle sensors can be used in some embodiments.

[0049] Figure 5A The design of a reconfigurable charging coil 65 for extracting power from the rotating magnetic field generated by the rotor 52 is shown diagrammatically, and a position sensor 66 is incorporated into the housing 30 adjacent to the rotor. The charging coil 65 includes four separate power coils 68 (in Figure 8-8DThe power coils 68 are each constructed of the same wire with the same number of turns wound around a ferromagnetic core 69 positioned within the housing 30 adjacent to the power magnets 59 of the rotor 52 to concentrate and direct the changing magnetic field lines extending between the opposite magnetic poles of the rotor 52 as the rotor rotates. Figure 5A The instantaneous rotor position in FIG shows the rotor angle at which maximum flux occurs in core 69. The magnetic field lines are shown clustered, with their direction from north pole to south pole indicated by the arrows. As the rotor continues to turn, the magnetic field will drop to zero and then reverse direction, increasing again to maximum flux when the rotor reaches 90° from the position shown. These rising and falling magnetic fields induce current to flow through each of the four power coils 68, allowing them to be used in ignition circuit 64 as four separate power supplies that are added together to generate sufficient DC voltage and current to ignite the engine spark plugs via the ignition coils.

[0050] Furthermore, the four power coils 68 can be electronically configured by the ignition circuit 64 as coils connected in series or in parallel. This enables the permanent magnet ignition device 24 to be self-powered over the entire engine speed range from starting to maximum rpm. No external power connection is required and no additional mechanical components are used.

[0051] The position sensor may be mounted on a printed circuit board (PCB), wherein the sensor 66 and the PCB together are referred to as a sensor board 67, as shown in FIG. Figure 5A The sensor plate 67 is mounted to the housing 30 adjacent to the sensor magnet 60 of the rotor 52, and the sensor magnet 60 is axially spaced from the power magnet 59 to avoid interfering with the magnetic field. Figure 5A , an end view of the rotor 52 is shown with the magnet 60 secured in the slot 61 at the second end 57 of the rotor. A sensor plate 67 is also shown to indicate its positioning relative to the sensor magnet 60 and, although not shown in this figure, is secured to the permanent magnet ignition device housing 30 in this position and orientation. In contrast to the four-pole power magnet 59, the sensor magnet 60 includes a single N-S pole pair, so that the sensor 66 generates a pair of complete quadrature sinusoidal waveforms per revolution of the rotor 52.

[0052] The fixed rotational orientation of the sensor magnet 60 on the rotor is shown at an angle α relative to the rotational orientation of the power magnet 59. Specifically, the angle α is the angle measured between the centerline of the N-S pole of the sensor magnet 60 and a particular pole of the power magnet 59. The angle α shown is arbitrary, but in use this angle will advantageously be predetermined to synchronize the permanent magnet ignition device with the piston TDC. For example, the north pole of the sensor magnet can be oriented directly adjacent to the position sensor (e.g., at Figure 5A3 o'clock position shown in FIG), whereby the poles of the power magnet will be in a desired alignment relative to the ferromagnetic core and coil. Such a desired alignment can be, for example, a position where the magnetic core 69 provides maximum or minimum flux, or a position between the maximum flux position and the minimum flux position, which provides a favorable or optimal timing of coil energization relative to the timing of the ignition pulse. Such alignment can be determined during the design phase and / or through testing.

[0053] Figure 5B An alternative sensor arrangement is depicted in which the sensor plate 67 is positioned adjacent the permanent magnet assembly 58 of the rotor 52 at an angular (or circumferential) position that is offset from the position of the power coil 68 and ferromagnetic core 69. This offset position forms an angle β with the angular position of the coil 68 and core 69. This angle is shown to be sufficiently large to avoid interference of the coil and core with the magnetic field sensed by the sensor 66. This angle may be Figure 5B , and angles less than 90° may be used depending on the circumferential extent of the coil / core package. In this embodiment, the rotor 52 does not need to have any separate sensor magnets 60, because the same magnets 59 used to energize the power coils 68 are also used for rotor position sensing. However, the advantage of reduced parts count may be offset by greater difficulty in obtaining the correct accuracy and resolution of position, and therefore more complex processing circuitry.

[0054] It is also advantageous for this embodiment to synchronize the position sensor output signal with the piston TDC and provide a desired angular alignment of the power magnet 59 with the power coil 68. This can be achieved by determining the position of the sensor plate 67 in the housing 30 relative to the angular position of the rotor poles and fixing it so that the desired alignment with the coil 68 is achieved. Such a position can be at Figure 5B At any discrete optional position shown or between such positions, as determined by design and / or testing.

[0055] Now turn Figures 6-10 , the ignition circuit 64 will now be described. Figure 6FIG2 is a functional block diagram of the ignition circuit 64 of the fully electronic permanent magnet ignition device 24, and shows connections to four spark plugs 70 via ignition leads 71. The ignition circuit 64 includes a position sensor 66 and a reconfigurable charging coil 65. The ignition circuit 64 receives magnetic field inputs solely from the reconfigurable charging coil 65 and solely from the rotating magnetic rotor 52. One magnetic input is the reversing magnetic field from the power magnet 59, while the other magnetic input comes from the position sensor magnet 60. The ignition circuit 64 is logically and (mostly) physically divided into three main circuits: a power circuit 80, a control circuit 90, and a discharge circuit 100. The power circuit 80 and the control circuit 90 are implemented on separate printed circuit boards (PCBs) mounted in the housing 30, and the discharge circuit 100 is largely a separately packaged component, also mounted in the housing. The circuit board and the discrete discharge circuit components are interconnected by solder traces extending therebetween.

[0056] Typically, power is extracted through a charging coil 65 comprised of four power coils 68 (L1A-L1D). The extracted power is induced in the power coils 68 from the changing magnetic field lines generated during the rotation of the rotor 52. These coils 68 form part of a power circuit 80, but are positioned adjacent to the rotor 52 for inductive coupling. The power circuit 80 uses the induced current from the coils 68 to charge a tank (or storage) capacitor in a tank capacitor circuit 74. This stored charge from the tank capacitor circuit 74 provides the power required to operate the control circuitry and the energy required by the discharge circuit to fire the spark plugs 70. For a four-stroke, four-cylinder engine with two pairs of identically timed pistons (i.e., with identical TDC), with one pair of pistons reciprocating together at 180° or other angle relative to the other pair, the ignition circuit 64 can be configured to operate in a wastefire configuration as shown, with cylinders 1 and 4 firing together (and cylinders 2 and 3 firing together), even though one cylinder in each pair is near TDC between the exhaust and intake strokes (rather than between the compression and power strokes). This allows the ignition system to operate with only two ignition coils 72 using only two channels A and B, with different ends of the secondary windings of the two ignition coils 72 connected to different spark plugs 70 in a different one of the two cylinders in the pair.

[0057] While various spark generation circuits may be used, the illustrated embodiment utilizes a capacitor discharge ignition (CDI) scheme in which the charge stored in the tank capacitor circuit 74 is ignited by power transistors QA, QB ( Figure 10 ) is drawn through the primary of the ignition coil 72 and then abruptly interrupted by the turning off transistor, thereby inducing a large voltage across the secondary of each ignition coil as is known. This is discussed further below in conjunction with the construction and operation of the discharge circuit 100.

[0058] By using multiple power coils 68 wound on a core 69 (either side-by-side or overlapping), sufficient power for the ignition circuit 64 and spark plugs can be achieved at both starting and normal speeds without a separate power supply, wherein the coil outputs are added together to produce sufficient voltage and current for charging the energy storage capacitor circuit 74 via the ignition coil 72 to the voltage required to ignite the spark plug 70. In the illustrated embodiment, four power coils 68 are used to generate this charging current using a reconfigurable charging coil method that sums or superimposes the coil voltages at low speeds and adds together the coil currents at high speeds. While four coils are used in the illustrated embodiment, other embodiments may use more or fewer power coils as needed or desired for a particular application.

[0059] like Figure 7 As shown, four capacitors are used which together form a hardwired tank capacitor circuit 74. Each capacitor TC1 to TC4 can be the same capacitor, for example 47uF, although different capacitances can be used. Figure 8 As will become clear from the power circuit, capacitors TC1, TC2 are wired in combination with the diode controlled summed voltage from power coil 68 to act as a voltage doubler to help charge storage capacitor TC3 to a sufficient DC voltage. Figure 6 As shown in FIG, storage capacitor circuit 74 (specifically, storage capacitor TC3) provides operating power to control circuit 90. To decouple the discharge of TC3 from control circuit operation during an ignition event, this power feed from TC3 is used to charge a fourth capacitor TC4 via a diode 75 mounted on the control circuit board, which prevents reverse power draw from TC4. Thus, both TC3 and TC4 operate as storage or reservoir capacitors to provide power to operate the ignition coil and the control circuit, respectively.

[0060] Figure 8The power circuit 80 is depicted. This largely analog circuit includes four power coils 680 and four interleaved subcircuits: a low-speed (start-up) circuit 82, a normal-mode circuit 84, a shutdown circuit 86, and an overvoltage protection circuit 88. The shutdown circuit 86 is connected to the P-lead of the standard pilot, which prevents magneto operation when shorted and allows the magneto to energize when disconnected, thereby allowing the engine to run. Once the P-lead connection is disconnected, the engine starter motor or other device can be used to spin up the engine and begin generating magneto operating power and cylinder firing. To this end, the ignition circuit 64 begins in a starting mode, using the low-speed circuit 82, which is configured to generate sufficient magneto operating power and spark energy to fire the spark plugs 70 even at engine speeds as low as 100 rpm, or possibly less, depending on the details of the circuit design and component selection. Once the engine begins running on its own, it accelerates to above a threshold engine speed, typically about 600 rpm. Thereafter, the power circuit 80 switches to its normal operating mode using the normal mode circuit 84 to generate the appropriate charging voltage and current for the energy storage capacitor TC3.

[0061] The engine shutdown can be manually controlled via the P-lead via a pilot ignition switch (not shown) that grounds the P-lead. This switches the power circuit 80 to shutdown mode by activating the shutdown circuit 86, which shorts one or more of the power coils 68, thereby preventing any of the four inductively linked power coils 68 from supplying operating power. Without any ignition spark, the engine decelerates to a stop.

[0062] The overvoltage protection circuit 88 utilizes some of the same circuitry used for shutdown to intermittently (i.e., each charging cycle as needed) shunt one or more power coils 68 when the voltage at the storage capacitor TC3 has reached its maximum desired charge voltage and after the ignition pulse to ensure that the voltage on TC3 does not rise too quickly.

[0063] All power circuit components can be integrated together onto a PCB, with the exception of the power coils 68 (i.e., L1A, L1B, L1C, L1D), which are wound around a ferromagnetic core 69 and adjacent to the magnetic rotor 52. The eight leads from those coils 68 can be soldered to the PCB at their designated electrical pads. As will be appreciated, the power input to the power circuit 80 is solely from the magnetic field lines of the rotating rotor's power magnets 59. Power coils L1A-L1D are all wound around the core 69 with the same polarity, as shown. Higher-voltage, lower-current power coils (such as may be formed with 1,000 or more turns of wire per coil) can collectively supply sufficient power, either by summing the voltages together in series for low-speed operation or by summing the currents together in parallel for higher-speed (normal) engine operation. In this way, a single charging coil package can fit within a standard permanent magnet ignition device housing and be electronically reconfigured into different coil configurations for different power and ignition needs. And this charging coil reconfiguration allows the permanent magnet ignition device 24 to generate sufficient voltage at the energy storage capacitor TC3 to ignite a typical aircraft piston engine spark plug 70 once per crankshaft revolution at speeds as low as 100 rpm or less, without the need for any mechanical pulse coupling or external power supply.

[0064] The power circuit 80 has five control inputs. The first control input is the pilot ignition switch P-lead, which is part of the shutdown circuit 86 and shuts off the engine ignition power when grounded. It is meant to be in an open circuit (high impedance) state to allow the ignition circuit to operate. The other four control inputs to the power circuit 80 come from the control circuit 90. Two of these (identified by the off-board wire connections marked in violet and white) are used to control the power circuit mode between startup mode and normal operating mode. The other two (identified by the wire connections marked in yellow and blue) disconnect the power supply coil that charges the energy storage capacitor during the ignition pulse, as will be explained.

[0065] The power circuit 80 has a circuit to the energy storage capacitor 74 (see Figure 7 ), the tank capacitor circuit 74 is part of the discharge circuit 100 and includes four discrete capacitors TC1-TC4. Since these capacitors are packaged and off-board, they are connected using color-coded wiring as indicated. As will be understood by those skilled in the art, the D11 / D13 / D25 / D26 diode-operated connections to capacitors TC1 and TC2 form an improved voltage multiplier for the power supplied by the four L1 power coils 68.

[0066] Figures 8A-8D Depicts Figure 8The four parts shown include four different sub-circuits 82, 84, 86, and 88 of the power circuit 80. Figures 8A-8D , only a specific sub-circuit is shown, with the remainder of the power circuit 80 grayed out to help identify the depicted sub-circuit components.

[0067] Figure 8A A low speed starting circuit 82 is depicted for generating magneto and spark power at very low engine rpm. This circuit 82 is controlled by a control circuit 90 using a transistor switch Q2A ( Figure 10 ) is activated, transistor switch Q2A switches the operating mode of the power circuit between start and normal based on the engine speed. The speed detector 93 ( Figure 10 ) is used to determine the rotor / motor speed. For the startup mode, switch Q2A is placed in the open (non-conducting) state, preventing current from flowing through the U3-U8 optoisolators, causing them to be disconnected and also keeping the thyristors (SCRs) Q13, Q15, Q17, Q20, Q21, and Q24 disconnected. Consequently, a forward bias voltage energizes the gates of thyristors Q12, Q14, Q18, Q19, Q22, and Q23, which electrically connect power coils L1A-L1D in series and are electrically connected to diodes D11, D13, D25, and D26 to form a full-wave rectifier, which also combines with capacitors TC1-TC3 to form an improved voltage multiplier.

[0068] In this starting mode, the voltage stacking of the four power coils 68 electrically connected in series helps overcome the lower induced voltages that occur at the slower rotational speeds of the magnetic rotor 52. This starting circuit 82 thus offers advantages over delayed-breaker permanent magnet ignition devices because it does not require an external power source and does not require a burst of sparks to be generated each time the engine is started. This circuit 82 is also advantageous over pulse-coupled magnets because it eliminates the mechanical wear and possible failure of one of these mechanical magnetos.

[0069] Now turn Figure 8B , shows a normal mode circuit 84 that takes over operation of the power circuit 80 once the engine is throttled beyond its low speed start range. The control circuit 90 monitors the engine speed via the angular position sensor 66 by comparing the engine speed to a predetermined speed threshold of 600 rpm, although other predetermined speeds above or below 600 rpm may be used. Below this threshold, the control circuit 90 maintains the power circuit 80 in the low speed (start) mode. Once the threshold is reached or exceeded, the control circuit 90 switches the power circuit 80 into a normal operating mode in which the engine is throttled beyond its low speed start range. Figure 8BThe circuit becomes active. This is achieved by energizing optoisolators U3-U8, which are connected to the gates of thyristors Q13, Q15, Q17, Q20, Q21, and Q24, allowing them to conduct. This electronically reconfigures the four power coils L1A-L1D into parallel-connected coils, which has the effect of forming a lower-turns, higher-amperage coil by summing their currents rather than their voltages. As in startup mode, this total power is used to charge storage capacitors TC3 and TC4 via the full-voltage rectifier formed by diodes D11, D13, D25, and D26.

[0070] Due to the higher rotational speed of the magnetic rotor 52 during normal engine operation, the accompanying higher rate of opposing magnetic field lines impinging on the power coils 68 induces a higher single-coil voltage than at lower speeds, thereby allowing a single one of the power coils 68 to generate sufficient peak voltage to charge the energy storage capacitor TC3 to the appropriate voltage. The remaining three power coils 68 connected in parallel with the first coil 68 multiply the amount of current supplied to the capacitor TC3, thereby allowing it to reach the appropriate voltage much faster than when the charging coil 65 is in the voltage summing configuration.

[0071] Figure 8C A P-lead activated shutdown subcircuit 86 is depicted. When the P-lead is grounded via the pilot's ignition switch, capacitor C9 discharges through R16 and R17 until transistor Q5A turns off, allowing current to conduct through diodes D3-D5 and resistor R14, forming a voltage divider with R8. This voltage divider turns on transistor Q3B, grounding the common node between resistors R5 and R6, thereby allowing pnp transistors Q1 and Q2 to conduct. This feeds power to the gates of thyristors Q11 and Q25, allowing conduction through the thyristors, shorting out any power coils L1A and L1D currently having positive polarity in the forward conduction direction of their associated thyristor. Because all four power coils 68 are tightly inductively coupled, the voltage across all coils drops to near zero, regardless of rotor rotation. Ignition then ends, causing engine power to drop.

[0072] Figure 8DA fourth subcircuit portion of the power circuit 80 is depicted; namely, the overvoltage protection circuit 88. This circuit 88 uses the same thyristors Q11, Q25 to activate when needed to at least temporarily stop charging the storage capacitors TC3, TC4 during certain conditions. The first condition is an overvoltage at the storage capacitors. Zener diode Z2 sets the overvoltage set point and can be, for example, a 47v, 1 / 2 watt Zener diode which, when its breakdown voltage is exceeded, turns on transistor Q3A, the collector of which is connected to the same common R5 / R6 node as Q3B and thus operates transistor Q3A to turn on Q1 and Q2, thereby unidirectionally shunting the power coils L1A, L1D. The second condition that triggers the overvoltage protection circuit is an ignition trigger ( Figure 6 and Figure 10 The same pulse signal used to turn the ignition coil power transistors QA and QB on and off is used to activate optoisolators U1 (channel A) and U2 (channel B). Thus, the optoisolators will alternate, turning their channels on only for the duration of the ignition pulse at a time. When the optoisolators are activated, current is conducted through a suitable (e.g., 47V or less) Zener diode Z1 and supplied to the base of transistor Q3A to temporarily shunt the coil 68 during ignition. This helps ensure that the voltage on the storage capacitor TC3 does not rise too rapidly after the spark.

[0073] Now turn Figure 9 and Figure 10 , shows the control circuit 90. As described above and as Figure 10 As shown, the charging force provided to the storage capacitor TC3 is input on the red line input terminal and charges the storage capacitor TC4 via the diode D3, which prevents current from being drawn from TC4 through the discharge circuit 100 when the ignition coil 72 is powered for spark ignition. The TC4 operates the power operation control circuit 90 and is developed into two regulated voltages, +5V and +12V power supplies using suitable linear switch mode or other voltage regulators 91, 92.

[0074] Figure 9 Depicted are an angular position sensor 66, various generated voltage set points, operational amplifiers, and comparators used with these set points to provide logic level binary values ​​that are Figure 10 Discrete logic circuits are used to determine the timing of the firing pulses for each of the two channels. The operational amplifier is located in Figure 9The comparator is located above the horizontal 2SPAN signal line shown, and below it. The set points are indicated by their names and are generated by various fixed and variable voltages; specifically, by the +5V logic supply voltage as the rotor 52 rotates, the storage capacitor TC3, and the sine and cosine waveforms provided by the angular position sensor 66. To normalize the set points to the sensor peak output, a voltage approximately twice the sensor peak amplitude (2SPAN) is generated and used to determine the voltages for the various set points. Furthermore, a minimum expected sensor peak amplitude is determined, for which a separate binary state signal (VSPAN>95%) is generated and used in the timing logic to enable the ignition pulse triggering. The position sensor set points represent specific points during a single cycle of the sensor output, which is once per rotor (and engine) rotation. Discrete logic circuitry uses these points to determine the crankshaft angle and, therefore, the appropriate ignition timing.

[0075] Reference Figure 11 The selection and use of these position sensor set points can be best understood by looking at the following diagram: The quadrature sinusoidal outputs of the position sensor are the sine and cosine waveforms produced when the poles of the sensor magnet pass through the sensor. 4371 TM The ignition timing of the ignition timing of the permanent magnet ignition device) is determined by the spark timing of the engine (permanent magnet ignition device), which needs to have a first fixed trigger angle for speeds under 600 rpm and a second fixed trigger angle for speeds above a predetermined threshold. The first low speed trigger angle is delayed from normal operation at 0° TDC, but can be in the range of about 0-10° after TDC. The second normal operation trigger angle is advanced to 20° before TDC, but can be in the range of about 18° to 28° before TDC. Moreover, the 600 rpm set point is only an exemplary speed threshold for the ignition timing change. Generally, any engine speed in the range of 250 rpm-600 rpm can be used. Regardless of the set points and thresholds selected, discrete logic circuitry needs to identify the correct position of the cyclic process of the spark along these sinusoidal waveforms at different engine speed ranges.

[0076] exist Figure 11 In the sensor output, each X-axis unit is a 15° rotation, and the sine and cosine amplitudes are normalized to 1.0. The sine wave is used for timing, while the cosine wave is used for orientation checking. Figure 11As shown, there are three main areas of concern. The first, Region 1, is any point during rotation when the peak amplitude of the sine wave is > 0.3 (or 30%). This represents the angular region where the spark is too late for the power stroke, and therefore the set point for this region is used to disable the ignition trigger during these angles. The second is Region 2, which is any time the peak amplitude of the cosine wave is < -0.5 (lower 50%). This is the angular region during which ignition can cause reverse rotation of the engine, and therefore the set point is also used to disable the ignition trigger in this angular region. Region 3 is the angle leading up to the desired spark ignition timing, and is used to enable the ignition circuit to produce the spark in a timely manner. As shown Figure 11 As shown, this region occurs when the cosine wave is > 0.5 and the sine wave is < -0.3.

[0077] Return Reference Figure 9 , it can be seen that these regions are identified by the various set points generated from the position sensor output, where comparators are used to represent the set points and their inverses are 0 / 5v binary voltages. Thus, 0v represents LO or binary 0 value, and 5v represents HI or binary 1 value.

[0078] Figure 10 The remainder of the control circuit 90 is included, and specifically, control logic that controls the timing of the ignition pulses relative to the rotational angle of the magnetic rotor according to the rotor speed based on the rotational angle data from the position sensor. The control logic includes a speed detector (circuit) 93 that switches the power circuit 80 between a low speed mode and a normal speed mode, thereby causing a change in the ignition timing of the ignition pulses depending on whether the rotor speed is above or below a predetermined speed. The control logic also includes two ignition channels A, B, each having an ignition coil trigger circuit 94A, 94B controlled by two corresponding trigger enable circuits 95A, 95B and timing logic 96A, 96B. The construction and operation of only the upper ignition channel A (circuitry 94A, 95A, 96A) will be described, with it being understood that channel B can be identical.

[0079] Trigger enable circuit 95A and timing logic 96A implement the above and Figure 11 The trigger enable circuit 95A uses discrete logic circuits to trigger the enable circuit 95A based on the Figure 9The signals generated by the setpoint circuit and comparator circuit on the left side of the figure identify the different state conditions that enforce the requirements of Regions 1-3. Circuit 95A includes SR latch 95A1. Because commercially available SR latches are set to a priority, the logic convention used in the circuit is to set (HI) when the trigger is to be disabled / blocked. Upper AND gate 95A2 represents the desired Region 3 for the desired ignition trigger to begin, and its output is connected to the reset of SR latch 95A1. Note that Region 3 is not the angle range in which the trigger occurs, but rather the region in which the trigger circuit 94A is switched to the enabled state for subsequent triggering. The remaining AND gate 95A3 and three OR gates 95A4, 95A5, and 95A6 set SR latch 95A1 to H1 to disable the trigger when in Regions 1 or 2, thereby requiring the crankshaft angle to re-enter Region 3 in each cycle before the trigger circuit 94A is re-enabled.

[0080] SR latch 95A1 is fed to another SR latch 96A1 in the timing logic, which is connected to its set input so that when ignition is enabled by the trigger enable circuit 95A, the set input of the timing logic SR latch 96A1 is at a logic 0 (LO), allowing its Q output to switch from HI to LO when reset, which then triggers the ignition coil trigger circuit 94A. Using three AND gates 96A2, 96A3, 96A4 and an OR gate 96A5, the timing logic 96A sets its SR latch 96A1 reset input if the following conditions are met: 1) Tank capacitor TC3 > 45 volts AND 2) Position sensor peak detector (VSPAN) > 95% of minimum expected voltage AND 3 (SIN > NEG_SET) AND 4A) Speed ​​> 600 RPM OR 4B) Position sensor 66 is at or above the +10° delayed trigger point (SIN > POS_SET). A binary speed indicator (above or below 600 rpm) is provided by a speed detector 93 described below.

[0081] Assuming that the trigger enable circuit 95A has enabled the timing logic 96A to initiate the ignition pulse, and the four timing logic conditions described above are met, including that the advance set point or the delay set point has been reached, the reset input of the timing logic's SR latch 96A1 will switch to HI, thereby setting Q = LO, which switches the output of the timing logic from HI to LO.

[0082] Ignition coil trigger circuit 94A uses an industry-standard 555 timer to generate a positive trigger pulse of a duration set by the R30 / C9 time constant. The 555 timer is triggered by a negative edge at its trigger input, which is the aforementioned HI-to-LO transition received from the timing logic's SR latch 96A1, and the resulting output of the 555 timer goes HI until the threshold input rises to 0.67*5V (3.35V). Trigger circuit 94A further includes a Darlington, push-pull, or other suitable high-gain driver to turn on power transistor QA for the duration of the 555 timer's output pulse. This pulse width can be set based on the magnetic components of power coil 68 so that, for example, they become saturated when the pulse ends and the current is interrupted.

[0083] The output of the 555 timer also returns a signal to the trigger enable circuit 95A to reset the output of the SR latch to HI, so that the trigger input of the 555 timer does not remain LO. In addition, the 555 timer powers the U1 and U2 optoisolators of the power circuit 80 to prevent excessive dv / dt after dead ignition.

[0084] Speed ​​detector 93 also uses a 555 timer and a D-type flip-flop (DFF) and transistor switch Q2A circuit to operate the normal-mode optoisolators U3-U8 of power circuit 80. Speed ​​detector 93 includes a timer and logic circuit that controls the advance and retardation of ignition timing relative to the output of position sensor 66, which indicates that the engine piston is at top dead center (TDC). The timer of speed detector 555 is connected in a one-shot configuration according to its data sheet. Speed ​​detector 93 takes as input one of the angular position sensors 66 that receives a status signal SIN>+0.3. To understand how speed detector 93 operates, assume that its timer is started in standby mode (OUT and DISCH are LOW, RES and TRIG are HI) and the speed detector output is LOW (meaning less than 600 rpm). Because the one-shot timer is set to 50 ms (halfway through a 600 rpm rotation), the output will remain HI for at least halfway through a 600 rpm rotation.

[0085] The output of the speed detector's timer is wired to the input of a D flip-flop (DFF). The output of the DFF is a speed range or state that indicates the operating mode (startup or normal) of the power circuit 80. The DFF clock is HI when the SINE input is below -0.3 and is HIGH half a revolution after the timer is started when SINE drops below +0.3.

[0086] As illustrated by the SIN>+0.3 signal, when the SINE output of the position sensor 66 rises above +0.3 (17.5°), the speed detector timer is triggered. After 50ms, the timer is reset (the output becomes LO). As indicated by the SIN<-0.3 signal, when SINE is greater than -0.3 (197.5°), the clock of the DFF transitions to HI half a revolution after the timer starts. If the half revolution is completed before the timer is reset, this indicates that the engine speed is above 600 rpm and the speed detector state is set to HI, placing the power circuit 80 in high speed mode so that the spark is triggered at the advance set point. Otherwise, the speed detector output remains in the LO state, keeping the power circuit 80 in low speed mode so that the spark is triggered at the retard set point.

[0087] As will be appreciated, the 600 rpm switch point between low-mode operation and normal-mode operation is only one of a number of predetermined speeds that may be used. Furthermore, the timing may be adjusted differently than between only the two trigger angles discussed above. Different trigger angle and engine speed ranges may be used; for example, in some embodiments, at a starting speed within a predetermined speed range of 250 rpm to 600 rpm, a first trigger angle of approximately 0-10° after TDC is used, and above the predetermined speed, a normal engine operating speed at a second trigger angle of approximately 18° to 28° before TDC is used.

[0088] In yet other embodiments, the ignition timing can be adjusted more finely, providing anywhere from continuously variable timing to an engine speed band that is finer (>2) than the two ranges typically provided by mechanical permanent magnet ignition devices. Through additional sensor inputs, the timing can be adjusted based not only on engine speed, but also on other factors that affect combustion, such as engine load, engine temperature, throttle position, atmospheric conditions (pressure, temperature, altitude and / or humidity), air / fuel mixture, and combustion chamber size and / or design.

[0089] When the permanent magnet ignition device is installed in the engine, the fully electronic permanent magnet ignition device 24 must be synchronized with the angular position of the crankshaft. This can be accomplished using a timing light marked on the propeller-mounted flywheel. During installation, coarse magnetic synchronization can be achieved by rotating the external drive gear 40 on the rotor to the correct position before meshing it with the engine's internal gears. Fine tuning for proper synchronization can then be accomplished by making slight rotational adjustments to the permanent magnet ignition device housing 30 before tightening it.

[0090] As above combined Figure 6As discussed, the discharge circuit 100 is a dual channel CDI circuit that includes TC3 energy storage capacitors charged via the red output, gray output, and black output from the power circuit 80, and includes channel A, B ignition coils 72 configured as primary coils connected to the high voltage terminal 36 of the permanent magnet ignition device 24 and step-up transformers with inductively coupled secondary coils, with multiple ignition leads 71 ​​connected to these step-up transformers, which route ignition pulses to the spark plugs 70. The discharge circuit 100 further includes two channels of solid-state transistor switches QA, QB, wherein the transistor of each channel and the ignition coil primary are connected in series in the circuit across a storage capacitor TC3 such that when the transistor is activated, charge from TC3 flows through the transistor and the primary, thereby establishing a magnetic field which remains until the transistor is deactivated, at which time the current flowing through the primary is interrupted to induce a high voltage pulse on the secondary coil which is fed via the ignition lead 71 to the associated spark plug 70.

[0091] The ignition system described above may be adapted for non-aviation applications, such as in small engines for residential and commercial equipment that include at least one spark plug. For these purposes, the rotor 52 and power coil 68 may be modified to increase or decrease the number of magnetic poles and coils, and appropriate changes may be made to the power supply and control circuits 80 and 90 to adjust the timing and amount of high voltage output for the intended application. Such modifications will be apparent to those skilled in the art.

[0092] It will of course be understood that the designation of different circuits (such as power circuits and control circuits 80, 90, etc.) is intended to aid in understanding the logical construction of the different functional portions of the entire ignition circuit 64, but that these functional portions of the ignition circuit 64 may be physically separated within the permanent magnet ignition device 24 or may be partially or fully integrated together.

[0093] The foregoing description is of one or more embodiments of the present invention. The present invention is not limited to the specific embodiments disclosed herein, but is limited only by the following claims. Furthermore, the statements contained in the foregoing description relate to the disclosed embodiments and should not be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiments will become apparent to those skilled in the art.

[0094] As used in this specification and claims, the terms "e.g.," "for example," "for instance," "such as," and "like," and the verbs "comprising," "having," "including," and their other verb forms, when used in conjunction with a list of one or more components or other items, are each to be interpreted as open-ended, meaning that the list is not to be regarded as excluding other, additional components or items. Other terms are to be interpreted using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. In addition, the term "and / or" is to be interpreted as including or. Thus, for example, the phrase "A, B, and / or C" should be interpreted to cover all of the following: "A"; "B"; "C"; "A and B"; "A and C"; "B and C"; and "A, B, and C."

Claims

1. A permanent magnet ignition device for an aircraft piston engine, comprising a magnetic rotor and an ignition circuit, wherein the ignition circuit includes a charging coil inductively coupled to a magnetic pole of the rotor, wherein: The charging coil includes a plurality of power coils that are electronically reconfigurable between a series connection and a parallel connection of the power coils by the ignition circuit.

2. The permanent magnetic ignition device according to claim 1, wherein: The permanent magnet ignition device includes a fully electronic permanent magnet ignition device, which uses an ignition circuit to generate and output an ignition pulse, and the ignition circuit only includes non-mechanically actuated electrical components.

3. The permanent magnetic ignition device according to claim 2, wherein: The ignition circuit includes a position sensor positioned adjacent to at least one magnet carried by the rotor, and wherein the ignition circuit derives power and data solely from a rotating magnetic field generated by the rotor during rotation.

4. A permanent magnet ignition device for an aircraft piston engine, comprising a magnetic rotor and an ignition circuit, the ignition circuit comprising a reconfigurable charging coil inductively coupled to a magnetic pole of the rotor, wherein: The reconfigurable charging coil includes a plurality of coils that inductively shut off the magnetic rotor and can be electronically reconfigured from a higher turns, lower amperage power coil for use during low speed operation to a lower turns, higher amperage power coil for use during high speed operation.

5. The permanent magnetic ignition device according to claim 4, wherein: The charging coil is configured as the higher turns, lower amperage power coil by electrically connecting the plurality of coils in series, and as the lower turns, higher amperage power coil by electrically connecting the plurality of coils in parallel.

6. The permanent magnetic ignition device according to claim 5, wherein: The ignition circuit includes a speed detector that detects whether the magnetic rotor, when rotating, indicates that an engine speed is above or below a speed threshold, and wherein the ignition circuit configures the plurality of coils to be connected in series when the speed detector indicates that the engine speed is below the speed threshold, and configures the charging coils to be connected in parallel when the speed detector indicates that the engine speed is above the speed threshold.

7. The permanent magnetic ignition device according to claim 4, wherein: The ignition circuit only includes non-mechanically actuated electrical components, wherein the permanent magnet ignition device includes a fully electronic permanent magnet ignition device.

8. The permanent magnetic ignition device according to claim 7, wherein: The ignition circuit includes a position sensor positioned adjacent to at least one magnet carried by the rotor, and wherein the ignition circuit derives power and data solely from a rotating magnetic field generated by the rotor during rotation.

9. A permanent magnetic ignition device comprising: case; a rotor assembly mounted in the housing and comprising a magnetic rotor and at least one bearing supporting the rotor for rotation in the housing, the rotor assembly having a first end and a second end, the rotor having a permanent magnet assembly located between the first and second ends, wherein the first end is externally accessible at an opening in the housing so that the rotor can be rotationally driven by an external drive component; and an ignition circuit including circuit components including at least one power coil and a position sensor each inductively coupled to the magnetic rotor, the ignition circuit including a high voltage output terminal mounted at an externally accessible location on the housing; The rotor assembly is a terminal mechanical device, which allows the rotor to rotate within the housing without transmitting the mechanical motion of the rotor to any of the circuit components.

10. The permanent magnetic ignition device according to claim 9, wherein: The ignition circuit is a fully electronic ignition circuit that uses only non-mechanically actuated electrical components within the permanent magnet ignition device to generate ignition pulses and distribute the ignition pulses to the output terminals.

11. The permanent magnetic ignition device according to claim 9, wherein: The ignition circuit includes a plurality of power coils that are electronically reconfigurable by the ignition circuit between a series connection and a parallel connection of the power coils.

12. A piston engine ignition system mechanically powered by a single magnetic rotor and having a plurality of high voltage output terminals adapted for connection to ignition leads for supplying ignition energy to one or more spark plugs via the ignition leads, the ignition system including a fully electronic ignition circuit operating solely on power provided by induction from the magnetic rotor, wherein: The ignition circuit generates the ignition energy from the received electrical power and selectively distributes the ignition energy to the output terminal as high-voltage ignition pulses, and wherein the ignition circuit includes a position sensor that detects the rotational angle of the magnetic rotor and further includes control logic that controls the timing of the ignition pulses relative to the rotational angle of the magnetic rotor according to rotor speed based on rotational angle data from the position sensor.

13. The ignition system of claim 12, wherein: The control logic further includes a speed detector that changes the firing timing of the firing pulses depending on whether the rotor speed is above or below a predetermined speed.

14. The ignition system of claim 13, wherein: The speed detector includes timing and logic circuitry that controls the advancement and retardation of the spark timing relative to the output of the position sensor indicating that the engine piston is at top dead center (TDC).

15. The ignition system of claim 14, wherein: The speed detector sets the ignition timing to a first trigger angle when the rotor speed is within a range from approximately 100 rpm up to the predetermined speed, and advances the ignition timing to a second trigger angle that is ahead of the first trigger angle when the rotor speed is higher than the predetermined speed.

16. The ignition system of claim 15, wherein: The first firing angle is approximately 0-10° after TDC, and the second firing angle is approximately 18°-28° before TDC, and wherein the predetermined speed is in the range of 250 rpm-600 rpm.

17. The ignition system of claim 12, wherein: The position sensor is a magnetoresistive sensor that outputs the rotational angle data as a quadrature sinusoidal waveform representing the rotational angle of the magnetic rotor, and wherein the control circuit includes logic circuitry that can use the sinusoidal waveform to trigger the ignition pulses only during specific rotational angles of the rotor.

18. The ignition system of claim 12, wherein: The ignition circuit includes a plurality of power coils positioned adjacent the magnetic rotor at a first angular position such that the power coils provide power to operate the ignition circuit, and wherein the position sensor is positioned adjacent the magnetic rotor at a second angular position such that the position sensor senses magnetic field lines of the magnetic rotor as the rotor rotates.

19. The ignition system of claim 12, wherein: The charging coil includes a plurality of power coils that are electronically reconfigurable between a series connection and a parallel connection of the power coils by the ignition circuit.

20. A permanent magnetic ignition device, comprising: Permanent magnet rotor; a ferromagnetic core positioned relative to the rotor, the ferromagnetic core for concentrating and directing varying magnetic field lines extending between opposing magnetic poles of the rotor as the rotor rotates; and an ignition circuit that inductively extracts power from the changing magnetic field lines, wherein the ignition circuit comprises: a power circuit having a reconfigurable charging coil comprising a plurality of power coils wound around the core and supplying inductive power to one or more output nodes of the power circuit; a high-voltage discharge circuit connected to the output node of the power circuit and generating high-voltage spark energy at a plurality of high-voltage output terminals; and a control circuit connected to at least one output node of the power circuit and capable of operating on power from at least one output node of the power circuit, wherein the control circuit includes control outputs connected to both the power circuit and the discharge circuit, the control outputs including at least one control output to the power circuit, the at least one control output electronically configuring the power coils in series or parallel; and at least another control output connected to the discharge circuit, the at least another control output causing a high voltage ignition pulse suitable for triggering a spark plug.

21. A permanent magnetic ignition device comprising: Permanent magnet rotor; a ferromagnetic core positioned relative to the rotor, the ferromagnetic core for concentrating and directing varying magnetic field lines extending between opposing magnetic poles of the rotor as the rotor rotates; and an ignition circuit that inductively extracts power from the changing magnetic field lines, wherein the ignition circuit comprises: a power circuit having a plurality of power coils wound around the core and supplying induced power to one or more output nodes of the power circuit; a capacitive discharge ignition (CDI) discharge circuit having at least one ignition storage capacitor charged via the one or more output nodes, at least one ignition coil configured as a step-up transformer, and at least one controllable solid-state switch, the step-up transformer having a primary coil coupled to one or more outputs of the CDI discharge circuit and an inductively coupled secondary coil, wherein the solid-state switch and the primary coil are connected in series across the ignition storage capacitor such that upon activation of the solid-state switch, charge from the ignition storage capacitor flows through the switch and the primary coil, thereby establishing a magnetic field that is maintained until the solid-state switch is deactivated, at which time current flow through the primary coil is interrupted to induce a high voltage pulse across the secondary coil; and a control circuit comprising at least one operating power storage capacitor; a position sensor positioned adjacent the magnetic rotor to detect magnetic field lines emanating from the rotor as the rotor rotates; and a timing circuit to control operation of the solid-state switch based on an angular position of the rotor sensed by the position sensor, The operating power storage capacitor of the control circuit is connected to the ignition storage capacitor via a diode, and the diode allows charging of the operating power storage capacitor and prevents the operating power storage capacitor from discharging the ignition storage capacitor through reverse current, so that the power coil provides operating power for both the ignition circuit and the control circuit.

22. The permanent magnetic ignition device according to claim 21, wherein: The control circuit includes at least two DC voltage regulators connected to receive input power from the operating power storage capacitor and output two different DC voltages for operation of the logic circuit.

23. The permanent magnetic ignition device according to claim 21, wherein: The plurality of power coils are electronically reconfigurable by the ignition circuit between a series connection and a parallel connection of the power coils.

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