Polarity discrimination device for ignition device

Abstract

To provide a polarity discrimination device for an ignition device, capable of accurately discriminating the polarity of an inspection device connected to a flywheel.SOLUTION: A polarity discrimination device for an ignition device comprises: a primary voltage acquisition unit 21 that acquires a primary voltage generated in an ignition coil of an external magnet type TCI ignition device that ignites an engine at an ignition timing according to rotation of a flywheel; an excess threshold detection unit 22 that detects that the acquired primary voltage exceeds a threshold voltage; and a polarity discrimination unit 23 that discriminates whether the ignition device is attached to the flywheel in a first polarity in which a positive voltage is generated as the primary voltage at the ignition timing, or a second polarity in which a negative voltage is generated as the primary voltage at the ignition timing, based on an excess detection pattern, which is a detection pattern in the excess threshold detection unit 22.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a discrimination device for discriminating the polarity of an ignition device used for engine ignition.

Background Art

[0002] As an ignition device for igniting a mixer in a cylinder, there are roughly known an ignition device of a TCI (Transistor Charge Ignition) system and an ignition device of a CDI (Capacitive Discharge Ignition) system. Patent Document 1 describes detecting the rotation of an engine using a primary side voltage which is a voltage signal of a primary coil of an ignition device, particularly in an external magnet type TCI ignition device. In this document, a device capable of continuously detecting a primary side voltage signal to detect the engine speed even when ignition stops during engine operation is proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such ignition devices are not integrally configured with the flywheel and may be removed and replaced separately from the flywheel due to causes such as lifespan and failure. In a conventional external magnet type TCI ignition device, the design is based on the premise that the ignition coil is connected to the flywheel with a specific polarity. Therefore, during removal and replacement, the connection must be made according to this polarity.

[0005] For example, in the device of Patent Document 1, since the voltage level of the primary voltage of the ignition coil is significantly larger on the negative (-) side than on the positive (+) side, the detection of the primary voltage is based on the voltage level adjusted accordingly. If it is connected with the opposite polarity, the detection of the primary voltage on the negative side cannot be achieved.

[0006] However, ignition devices used in general-purpose engines and the like may have very similar appearances even if their polarities are opposite. Because their appearances are very similar, the workers in dealers and sales stores have been burdened with the attention to prevent mis-incorporating the ignition device with the wrong polarity during after-sales services such as parts replacement.

[0007] Therefore, the present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a polarity discrimination device for an ignition device that can accurately discriminate the polarity of the ignition device connected to the flywheel.

Means for Solving the Problems

[0008] In order to solve the above problems, a polarity discrimination device for an ignition device according to the present invention includes a primary voltage acquisition unit that acquires a primary voltage generated in an ignition coil of an external magnetic type TCI ignition device that ignites an engine at an ignition timing corresponding to the rotation of a flywheel, a threshold exceedance detection unit that detects that the acquired primary voltage exceeds a threshold voltage, and based on a pattern of exceedance detection that is a pattern of detection in the threshold exceedance detection unit, determines whether the ignition device is attached to the flywheel with either a first polarity in which a positive voltage is generated as the primary voltage at the ignition timing or a second polarity in which a negative voltage is generated as the primary voltage at the ignition timing. It is characterized by comprising a polarity discrimination unit.

[0009] According to this aspect, the polarity of the ignition device connected to the flywheel can be accurately discriminated.

[0010] The polarity discrimination unit may determine, based on the fact that the acquired primary voltage continuously exceeds either the positive threshold voltage or the negative threshold voltage in the threshold exceedance detection unit, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity.

[0011] The polarity discrimination unit may determine, based on the number of times the acquired primary voltage is detected to exceed the positive threshold voltage and the number of times the acquired primary voltage is detected to exceed the negative threshold voltage in the threshold exceedance detection unit, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity.

[0012] The polarity discrimination unit may determine, based on the time intervals between adjacent timings among the plurality of timings when the acquired primary voltage is detected to exceed the positive threshold voltage and the time intervals between adjacent timings among the plurality of timings when the acquired primary voltage is detected to exceed the negative threshold voltage in the threshold exceedance detection unit, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity.

[0013] The polarity discrimination unit may further include a polarity switching unit that switches the polarity of the primary voltage when it is determined to be the second polarity.

[0014] The polarity discrimination unit may further include a warning unit that outputs a warning when it is determined to be the second polarity.

[0015] A rotation detection system may include any one of the above-described polarity discrimination devices, a spark plug connected to the secondary coil of the ignition device, a magnet rotor installed on the flywheel, and an engine control device that controls the engine.

Brief Description of the Drawings

[0016]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0017] In the following description, an engine control device for controlling a V-type 2-cylinder 4-cycle engine will be described as an example. However, the engine that can be controlled by the engine control device of the present embodiment is not limited to this, and can be applied to a multi-cylinder 4-cycle engine having n cylinders (n is an integer of 2 or more).

[0018] In a 4-cycle engine, a spark discharge is generated by a spark plug attached to the cylinder of the engine at the normal ignition position set near the crank angle position (the rotational angle position of the crankshaft) when the piston reaches the top dead center in the compression stroke. For this reason, the fuel in the cylinder is burned only once while the crankshaft rotates twice.

[0019] The ECU2 (see FIG. 5), which functions as a polarity determination device for the ignition device described in this specification, includes a primary voltage acquisition unit 21, a threshold exceedance detection unit 22, and a polarity determination unit 23. The primary voltage acquisition unit 21 acquires the primary voltage generated in the ignition coil of an external magnetic TCI ignition device that ignites the engine at the ignition timing corresponding to the rotation of the flywheel. The threshold exceedance detection unit 22 detects that the acquired primary voltage exceeds the threshold voltage. The polarity determination unit 23 determines, based on the detection pattern in the threshold exceedance detection unit 22, whether the ignition device is attached to the flywheel with the first polarity in which a positive voltage is generated as the primary voltage at the ignition timing, or the second polarity in which a negative voltage is generated as the primary voltage at the ignition timing.

[0020] According to this polarity determination device for the ignition device, the polarity of the ignition device connected to the flywheel can be accurately determined. (First Embodiment) FIG. 1 is a diagram showing a configuration example of an engine and an engine control device according to this embodiment. FIG. 1 shows an engine 1 and an electronic control unit (ECU) 2 that constitutes a main part of the engine control device for controlling the engine 1. The polarity determination device for the ignition device in this embodiment is realized by the electronic control unit (ECU) 2.

[0021] The engine 1 includes an engine body having a crankcase 100, a first cylinder 101 and a second cylinder 102, a crankshaft 103 supported by the crankcase 100, and first and second pistons (not shown) arranged in the first cylinder 101 and the second cylinder 102 and connected to the crankshaft 103 via connecting rods, and first and second ignition devices IU1 and IU2 provided corresponding to the first cylinder 101 and the second cylinder 102, respectively.

[0022] At the heads of the first cylinder 101 and the second cylinder 102, an intake port opened and closed by an intake valve and an exhaust port opened and closed by an exhaust valve are provided. The intake ports of the first cylinder 101 and the second cylinder 102 are connected to a throttle body 106 via intake manifolds 104 and 105 respectively, and the exhaust ports of the first cylinder 101 and the second cylinder 102 are connected to an exhaust pipe (not shown) via exhaust manifolds 107 and 108 respectively. In the illustrated example, an injector (fuel injection valve) INJ is attached to the throttle body 106, and fuel is injected from the injector INJ into the space within the throttle body 106. Further, upstream of the injector INJ in the throttle body 106, a throttle valve THV that constitutes an operation part operated when adjusting the engine rotation speed is attached. The throttle valve THV is operated by an actuator (not shown) composed of a step motor or the like. Also, a first spark plug PL1 and a second spark plug PL2 are attached to the head of the first cylinder 101 and the head of the second cylinder 102 respectively, and the discharge gaps of these spark plugs are inserted into the combustion chambers within the first cylinder 101 and the second cylinder 102. The V-type two-cylinder four-cycle engine shown in FIG. 1 has a structure in which the first cylinder 101 is positioned at a position separated by an angle of β° (0 < β < 180) from the position of the second cylinder 102 to the front side in the normal rotation direction of the crankshaft (counterclockwise on the drawing surface of FIG. 1), and the first cylinder 101 and the second cylinder 102 are arranged in a V-type. In this embodiment, β = 90. Also, a flywheel 109 is attached to one end of the crankshaft 103, and by attaching permanent magnets to the outer peripheral part of the flywheel 109, a magnet rotor M having a three-pole magnetic pole part with S poles formed on both sides of the N pole is constituted. Outside the flywheel 109, a first ignition device IU1 and a second ignition device IU2 provided for the first cylinder 101 and the second cylinder 102 of the engine respectively are arranged.

[0023] The first ignition device IU1 and the second ignition device IU2 respectively constitute the main parts of ignition devices for igniting the first cylinder 101 and the second cylinder 102. The first ignition device IU1 is connected to the first spark plug PL1, and the second ignition device IU2 is connected to the second spark plug PL2. These ignition devices IU are arranged at positions suitable for causing an ignition operation in the corresponding cylinders and are fixed to an ignition device mounting portion provided on an engine case, cover, or the like. In the illustrated example, the first ignition device IU1 is arranged at a position separated from the position of the second ignition device IU2 by an angular interval of 90° on the front side in the normal rotation direction of the crankshaft. The flywheel magnet is constituted by the magnet rotor M, the first ignition device IU1, and the second ignition device IU2. The first ignition device IU1 and the second ignition device IU2 are external magnetic type ignition devices. That is, the ignition device IU includes an armature core having magnetic pole portions facing the magnetic poles of the magnet rotor M with a gap at both ends, and an ignition coil having a primary coil and a secondary coil wound as a power generation coil around the armature core. The ignition coil has a primary current controlled by a primary current control circuit, and a high voltage for ignition is induced in the secondary coil at the ignition timing of the engine. As the primary current control circuit, generally, a capacitor discharge type circuit or a current interruption type circuit is known. However, in this embodiment, since the ignition device IU is a TCI ignition device, a current interruption type circuit is used as the primary current control circuit.

[0024] Here, the ignition device IU will be further described. FIG. 2 is a diagram showing a configuration example of the ignition device IU according to this embodiment. In this embodiment, the first ignition device IU1 and the second ignition device IU2 have the same configuration as each other, except that they are provided corresponding to different cylinders. As shown in FIG. 2, the ignition device IU includes an ignition coil IG having a primary coil W1 and a secondary coil W2, an armature core Ac, a voltage detection circuit DV, a primary current control switch SW, and an ignition control unit Cont. The first ignition device IU1 and the second ignition device IU2 are each packaged by housing these components in a case.

[0025] The ignition coil IG includes a first ignition coil IG1 provided corresponding to the first cylinder and a second ignition coil IG2 provided corresponding to the second cylinder. The first ignition coil IG1 is composed of a primary coil W11 wound around a first armature core Ac1 and a secondary coil W21, and the second ignition coil IG2 is composed of a primary coil W12 wound around a second armature core Ac2 and a secondary coil W22.

[0026] The armature core Ac of the ignition coil IG forms a magnetic path with the magnetic poles of the magnet rotor M, and the magnitude and direction of the magnetic flux formed based on the magnetic path formed between the magnet rotor M change as the flywheel rotates. Due to this change, voltages are generated in the primary coil W1 and the secondary coil W2.

[0027] The primary current control switch SW is composed of a semiconductor switch element such as a transistor or a MOSFET and is connected in parallel to the primary coil W1. The primary current control switch SW is turned on when a drive signal is applied from the primary coil W1 side when a voltage of a predetermined polarity is induced in the primary coil W1 of the ignition coil. When the primary current control switch SW is turned on, a predetermined voltage is applied to the primary coil W1.

[0028] The voltage detection circuit DV is a circuit that detects the voltage across both ends of the primary coil W1, and is composed of a resistance voltage division circuit or the like connected in parallel across both ends of the primary coil W1 of the ignition coil. The voltage detection circuit DV detects the voltage (primary voltage) across both ends of the primary coils W1 of the ignition coils IG1 and IG2 connected respectively in the ignition device IU1 and the second ignition device IU2, and outputs primary voltage detection signals V11 and V12. Note that the primary voltage detection signal V11 is output from the voltage detection circuit DV1 of the first ignition device IU1, and the primary voltage detection signal V12 is output from the voltage detection circuit DV2 of the second ignition device IU2. The primary voltage detection signal V11 output from the voltage detection circuit DV1 of the first ignition device IU1 and the primary voltage detection signal V12 output from the voltage detection circuit DV2 of the second ignition device IU2 are supplied to the electronic control unit 2 shown in FIG. 1.

[0029] The ignition control unit Cont controls the primary current control switch SW so as to turn off the voltage applied to the primary coil W1 in the on state. Generally, in an engine ignition device, the engine rotation speed is detected, the ignition position θi of the engine is calculated with respect to the detected rotation speed, and when the calculated ignition position is detected, a high voltage for ignition is applied to the spark plug to control the primary current control switch SW so as to perform the ignition operation.

[0030] Before explaining the electronic control unit (ECU) 2 that functions as the polarity discrimination device of the ignition device of the present embodiment, the polarity of the ignition device will be explained.

[0031] FIG. 3 is a diagram showing the change in the magnetic flux of the ignition coil IG and the voltages generated in the primary coil W1 and the secondary coil W2 due to the change in the magnetic flux. In FIG. 3, (a) shows the change in the magnetic flux of the ignition coil IG, and (b) shows the voltages generated in the primary coil W1 and the secondary coil W2.

[0032] As the engine rotates and the flywheel 109 rotates, the magnet rotor M attached to the outer peripheral portion of the flywheel 109 rotates. When the magnet rotor M rotates, as shown in Fig. 3(a), the direction and magnitude of the magnetic flux in the armature core Ac of the ignition coil IG that forms a magnetic path with the magnet rotor M change. Due to this change, a voltage V1 as shown in Fig. 3(b) is generated in the primary coil W1 and the secondary coil W2.

[0033] Fig. 4 is a diagram for explaining the control of the ignition device IU when inducing a spark discharge in the secondary coil W2. Fig. 4(a) shows the change in the magnetic flux of the ignition coil IG due to the rotation of the flywheel. Fig. 4(b) is a diagram showing the ON / OFF of the primary current control switch SW. Fig. 4(c) is a diagram showing the current I1 flowing through the primary coil W1 when the switch SW is ON. Fig. 4(d) is a diagram showing the electromotive force V2 generated in the secondary coil. Fig. 4(e) is a diagram showing the current I2 flowing through the secondary coil.

[0034] In the ignition device IU of this embodiment, as shown in Fig. 4(b), the primary current control switch SW is turned on at a predetermined timing, and a predetermined voltage Vt is applied to the primary coil W1. As shown in Fig. 4(c), even when the predetermined voltage Vt is applied, no current immediately flows through the primary coil W1, and the current gradually increases. Due to this current, the magnitude of the magnetic flux in the armature core Ac also changes.

[0035] Furthermore, so that a spark discharge occurs in the secondary coil W2 at a predetermined ignition timing, the primary current control switch SW is turned off, and the current in the primary coil is cut off. When the current in the primary coil W1 is cut off, the magnetic flux passing through the primary coil W1 and the secondary coil W2 changes, but a rapid electromotive force is generated in the secondary coil W2 to prevent this change.

[0036] The pattern of the current generated in the primary coil and the secondary coil described with reference to FIG. 4 differs depending on the polarity with which the ignition device IU is attached to the flywheel 109 of FIG. 1. That is, when the ignition device is attached with the reverse polarity, although the direction of the current flowing due to the voltage generated in the primary coil and the secondary coil by the change in the magnetic flux in the magnetic circuit does not change, the direction (positive or negative) of the current generated by the voltage applied to the primary coil when the switch SW is turned on is reversed. Therefore, it does not match the pattern of the current generated in the primary coil and the secondary coil described with reference to FIG. 4.

[0037] For example, when detecting the rotation of the engine based on obtaining the primary voltage detection signal V1 output from the voltage detection circuit DV of the ignition device IU and detecting a positive voltage of a predetermined magnitude, a problem occurs if the ignition device is not attached to the flywheel with the correct polarity (also referred to as the first polarity). When attached with the reverse polarity (also referred to as the second polarity), a negative voltage is generated as the primary voltage at the ignition timing, so a positive voltage of a predetermined magnitude that should originally be detected is not correctly generated, and the rotation may not be detected by the original detection circuit.

[0038] The polarity discrimination device of the ignition device according to the present embodiment discriminates the polarity with which the ignition device is attached to the flywheel. The polarity discrimination device can be realized as a part of the function of the electronic control unit (ECU) 2. FIG. 5 is a functional block diagram of the electronic control unit (ECU) 2 according to the present embodiment. The electronic control unit 2 includes a primary voltage acquisition unit 21, a threshold exceedance detection unit 22, a polarity discrimination unit 23, a polarity switching unit 24, and an engine control unit 25. Each configuration may be configured by a dedicated hardware circuit, or may be configured as firmware or software on hardware such as a CPU and a memory.

[0039] The primary voltage acquisition unit 21 acquires the primary voltage detection signals V11 and V12 by receiving over time the primary voltage detection signal V11 output from the voltage detection circuit DV of the first ignition device IU1 and the primary voltage detection signal V12 output from the voltage detection circuit DV of the second ignition device IU2.

[0040] The threshold - exceeding detection unit 22 detects that the primary voltage detection signals V11 and V12 acquired by the primary voltage acquisition unit 21 exceed a threshold voltage. The threshold voltage can be set to a value capable of detecting a change in the primary voltage that characteristically occurs due to the rotation of the engine, and a positive threshold voltage and a negative threshold voltage can be set. The threshold - exceeding detection unit 22 can detect the exceedance depending on whether the primary voltage detection signals V11 and V12 are larger than the positive threshold voltage or are larger on the negative voltage side than the negative threshold voltage.

[0041] When the threshold - exceeding detection unit 22 detects that the threshold voltage has been exceeded, it sends to the polarity discrimination unit 23 which of the positive and negative threshold voltages the exceedance has been detected for.

[0042] The polarity discrimination unit 23 discriminates the polarities of the first ignition device IU1 and the second ignition device IU2 based on the pattern of the exceedance detection, which is the pattern of the detection that the threshold voltage has been exceeded by the threshold - exceeding detection unit 22. Since the pattern of the exceedance detection corresponds to the pattern of the change in the primary voltage detection signals V11 and V12, the polarities of the first ignition device IU1 and the second ignition device IU2 can be discriminated based on the pattern of the exceedance detection. For example, when the polarity discrimination unit 23 determines that the pattern of the exceedance detection detected by the threshold - exceeding detection unit 22 corresponds to the change in the primary voltage detection signals V11 and V12 of the first pattern, it can be discriminated that the ignition device is attached to the flywheel with the first polarity, and when it is determined that the pattern of the exceedance detection corresponds to the change in the primary voltage detection signals V11 and V12 of the second pattern, it can be discriminated that the ignition device is attached to the flywheel with the second polarity.

[0043] FIG. 6 is a diagram showing an example of a pattern of changes in the primary voltage detection signals V11 and V12 when the engine makes one revolution. In FIG. 6, (a) and (b) are patterns of the primary voltage detection signals output from the ignition devices IU having opposite polarities. In this specification, FIG. 6(a) is referred to as the first pattern, and FIG. 6(b) is referred to as the second pattern. In the following description, it is assumed that when the polarity of the ignition device IU is the first polarity, the primary voltage detection signal changes in the first pattern, and when the polarity of the ignition device IU is the second polarity, the primary voltage detection signal changes in the second pattern.

[0044] In this embodiment, the polarity determination unit 23 determines the polarity based on the fact that the threshold value exceeding detection unit 22 has continuously detected that the primary voltage detection signals V11 and V12 have exceeded either the positive threshold voltage “V T ” or the negative threshold voltage “-V T ”.

[0045] In the example shown in FIG. 6, when it is continuously detected that the positive threshold voltage “V T ” has been exceeded, it is determined that the pattern is (a), and the ignition device can be determined to have the first polarity. Similarly, when it is continuously detected that the negative threshold voltage “-V T ” has been exceeded, it is determined that the pattern is (b), and the ignition device can be determined to have the second polarity.

[0046] The polarity switching unit 24 switches the processing of the primary voltage detection signals V11 and V12 to the opposite polarity when the polarity determined by the polarity determination unit 23 is not the original proper polarity. For example, the primary voltage detection signals V11 and V12 can be used when detecting rotation, but the polarity of the threshold voltage used for detecting rotation may be switched to the opposite polarity, or the polarities of the primary voltage detection signals V11 and V12 may be switched to the opposite polarity.

[0047] The engine control unit 25 detects the rotation of the engine based on the primary voltage detection signals V11 and V12 acquired by the primary voltage acquisition unit 21, and controls the driving of the injector based on the rotation of the engine, thereby performing engine control.

[0048] Next, the detection and discrimination process executed by the polarity discrimination device of the ignition device according to this embodiment will be described. FIG. 7 is a flowchart of the detection and discrimination process in the polarity discrimination device. First, when the engine starts rotating due to the ignition switch being turned on, the primary voltage acquisition unit 21 acquires primary voltage detection signals V11 and V12 (step S701). The primary voltage acquisition unit 21 sends the acquired primary voltage detection signals V11 and V12 to the threshold exceedance detection unit 22.

[0049] The threshold exceedance detection unit 22 separately detects whether or not the received primary voltage detection signals V11 and V12 exceed the threshold voltage (step S702). When the threshold exceedance detection unit 22 detects that the threshold voltage has been exceeded (step S702: Yes), it sends the detection result to the polarity discrimination unit 23. When the threshold exceedance detection unit 22 fails to detect that the threshold voltage has been exceeded (step S702: No), it returns to step S701 and acquires the primary voltage detection signals V11 and V12 again.

[0050] The polarity discrimination unit 23 discriminates the polarities of the first ignition device IU1 and the second ignition device IU2 by determining the pattern of exceedance detection using the detection result received from the threshold exceedance detection unit 22 (step S703). For example, when it is determined that the pattern of exceedance detection for the primary voltage detection signal V11 is the first pattern and the pattern of exceedance detection for the primary voltage detection signal V12 is the second pattern, it can be discriminated that the first ignition device IU1 is attached to the flywheel with the first polarity and the second ignition device IU2 is attached to the flywheel with the second polarity.

[0051] When the polarity determination unit 23 receives from the threshold excess detection unit 22 the detection of the excess of the threshold voltage, it discriminates the first polarity by determining that the pattern of the change in the primary voltage detection signal is the pattern of FIG. 6(a), and executes either the first determination process or the second determination process of discriminating the second polarity by determining that the pattern of the change in the primary voltage detection signal is the pattern of FIG. 6(b).

[0052] Here, the process of determining the polarity, which is executed in step S703, will be described in more detail with reference to FIGS. 8 to 12. FIG. 8 shows the polarity determination process of step S703 including the first determination process 100 and the second determination process 200. FIG. 9 shows the details of the first determination process 100, and FIG. 10 shows the details of the second determination process 200. FIG. 11 shows the change in the primary voltage detection signal when the ignition device has the first polarity, corresponding to the change in the detection flag and the change in the continuous detection counter. FIG. 12 shows the change in the primary voltage detection signal when the ignition device has the second polarity, corresponding to the change in the detection flag and the change in the continuous detection counter. FIG. 9 shows the “+ signal determination process” executed when receiving from the threshold excess detection unit 22 the detection of the excess of the positive threshold voltage, as the first determination process 100. FIG. 10 shows the “− signal determination process” executed when receiving from the threshold excess detection unit 22 the detection of the excess of the negative threshold voltage, as the second determination process 200.

[0053] First, the case where the device to be discriminated is the ignition device of the first polarity shown in FIG. 11 will be described. At the time point A when the primary voltage exceeds the positive threshold voltage “V T ”, when receiving from the threshold excess detection unit 22 the detection of the excess of the positive threshold voltage, the polarity determination unit 23 starts the polarity determination process of FIG. 8. The polarity determination unit 23 determines that it has received the detection of the excess of the positive threshold voltage (step S801: Yes) and executes the first determination process 100 of FIG. 9.

[0054] In the first determination process 100 shown in FIG. 9, it is determined whether the polarity is undetermined (step S901). Since it is undetermined (step S901: Yes), it is determined whether the “+ detection flag” is “1” (step S902). At time point A, since the “+ detection flag” is “0” (step S902: No), the “+ detection flag” is set to “1” (step S906), and the first determination process 100 ends.

[0055] Also, when receiving at time point B that the threshold - exceeding detection unit 22 has detected an excess of the negative threshold voltage, the polarity determination unit 23 starts the polarity determination process of FIG. 8. The polarity determination unit 23 determines that what has been received is not an excess of the positive threshold voltage (step S801: No), and executes the second determination process 200 of FIG. 10.

[0056] In the second determination process 200 shown in FIG. 10, it is determined whether the polarity is undetermined (step S1001). Since it is undetermined (step S1001: Yes), it is determined whether the “- detection flag” is “1” (step S1002). At time point B, since the “- detection flag” is “0” (step S1002: No), the “- detection flag” is set to “1” and the “+ detection flag” is cleared (set to “0”) (step S1006), and the second determination process 200 ends.

[0057] Furthermore, when receiving from the threshold - exceeded detection unit 22 the detection of the exceeding of the positive threshold voltage at time point D, the polarity discrimination unit 23 executes the first determination process 100 of FIG. 9 according to the determination (Yes) in step S801 of FIG. 8. In the first determination process 100 of FIG. 9, it is determined whether the polarity is undetermined (step S901). Since it is undetermined (step S901: Yes), it is determined whether the “+ detection flag” is “1” (step S902). At time point D, since the “+ detection flag” is “1” (step S902: Yes), the “+ continuous counter” is incremented from “1” to “2” (step S903). After the increment, it is determined whether the “+ continuous counter” is 2 or more and whether the “− continuous counter” is “1” (step S804). At time point D, the “+ continuous counter” is “2” and the “− continuous counter” is “1”, so it is determined that the ignition device has the first polarity (step S905). The “+ detection flag” is set to “1” and the “− detection flag” is cleared (step S906), and the first determination process 100 is terminated.

[0058] Next, the case where the discrimination target is the ignition device of the second polarity shown in FIG. 12 will be described. At time point A when the primary voltage exceeds the negative threshold voltage “−V T ”, when receiving from the threshold - exceeded detection unit 22 the detection of the exceeding of the negative threshold voltage, the polarity discrimination unit 23 executes the second determination process 200 of FIG. 10 according to the determination (No) in step S801 of FIG. 8. In the second determination process 200, it is determined whether the polarity is undetermined (step S1001). Since it is undetermined (step S1001: Yes), it is determined whether the “− detection flag” is “1” (step S1002). At time point A, since the “− detection flag” is “0” (step S1002: No), the “− detection flag” is set to “1” (step S1006), and the second determination process 200 is terminated.

[0059] Also, when receiving from the threshold - exceeding detection unit 22 the detection of the exceeding of the positive threshold voltage at time point B, the polarity discrimination unit 23 executes the first determination process 100 according to the determination (Yes) in step S801 of FIG. 8. In the first determination process 100 of FIG. 9, it is determined whether the polarity is undetermined (step S901). Since it is undetermined (step S901: Yes), it is determined whether the “+ detection flag” is “1” (step S902). At time point B, since the “+ detection flag” is “0” (step S902: No), the “+ detection flag” is set to “1” and the “− detection flag” is cleared (step S906), and the first determination process 100 ends.

[0060] Furthermore, when receiving from the threshold - exceeding detection unit 22 the detection of the exceeding of the negative threshold voltage at time point D, the polarity discrimination unit 23 executes the second determination process 200 of FIG. 10 according to the determination (No) in step S801 of FIG. 8. In the second determination process 200 of FIG. 10, it is determined whether the polarity is undetermined (step S1001). Since it is undetermined (step S1001: Yes), it is determined whether the “− detection flag” is “1” (step S1002). At time point D, since the “− detection flag” is “1” (step S1002: Yes), the polarity discrimination unit 23 increments the “− continuous counter” from “1” to “2” (step S1003).

[0061] After the increment, the polarity discrimination unit 23 determines whether the “− continuous counter” is 2 or more and whether the “+ continuous counter” is “1” (step S1004). At time point D, since the “− continuous counter” is “2” and the “+ continuous counter” is “1”, it is determined that the ignition device has the second polarity (step S1005), the “− detection flag” is set to “1” and the “+ detection flag” is cleared (step S1006), and the second determination process 200 ends.

[0062] The polarity discrimination unit 23 further determines whether the discrimination has been completed (polarity discrimination has been performed in the first discrimination process 100 or the second discrimination process 200) (step S704). If the discrimination has been completed (step S704: Yes), the polarity of the discriminated ignition device is sent to the polarity switching unit 24 (step S705).

[0063] If the discrimination has not been completed (step S704: No), the polarity discrimination unit 23 returns to step S701 again to acquire the primary voltage detection signals V11 and V12.

[0064] The polarity switching unit 24 determines whether the polarity of the ignition device received from the polarity discrimination unit 23 is the first polarity (step S706). This determination is for identifying whether the ignition device is attached to the flywheel with the correct polarity.

[0065] If it is determined that it is not attached with the correct polarity (step S706: No), the polarity switching unit 24 switches the processing of the primary voltage detection signals V11 and V12 to the reverse polarity (step S707). If it is determined that it is attached with the correct polarity (step S706: Yes), the detection discrimination process is terminated.

[0066] Thus, according to the polarity discrimination device for the ignition device of the first embodiment, the polarity of the ignition device connected to the flywheel can be accurately discriminated. Furthermore, if it is determined that it is not attached with the correct polarity, the polarity can be switched, so that even if the polarity of the ignition device is incorrectly attached, the operation can continue without problems. (Second Embodiment) In the first embodiment, in the polarity determination unit 23, the determination was made based on continuously detecting that the primary voltage detection signal exceeded either the positive threshold voltage or the negative threshold voltage. Instead of this determination method, in this embodiment, the determination is made based on the number of times the primary voltage detection signal is detected to exceed the positive threshold voltage and the number of times the primary voltage detection signal is detected to exceed the negative threshold voltage. Since other configurations are the same as those in the first embodiment, descriptions of the same parts are omitted, and only different parts will be described.

[0067] The polarity determination unit 23 compares the number of times the primary voltage detection signals V11 and V12 are detected to exceed the positive threshold voltage " T " and the number of times the primary voltage detection signals V11 and V12 are detected to exceed the negative threshold voltage " T ", and makes a determination based on that the detection count of either one is greater than the other by a predetermined number of times. For example, when the number of times of one of them becomes twice the number of times of the other, it can be determined based on whether the threshold voltage of that one is positive or negative.

[0068] In the example shown in FIG. 6, when the number of times the positive threshold voltage " T " is detected is 4, which is twice the number of times the negative threshold voltage " T " is detected, it is determined that it is the pattern of (a), and it can be determined that it is the first polarity. Similarly, when the number of times the negative threshold voltage " T " is detected is 4, which is twice the number of times the positive threshold voltage " T " is detected, it is determined that it is the pattern of (b), and it can be determined that it is the second polarity.

[0069] Regarding the process of determining the polarity that the polarity determination unit 23 in the second embodiment executes as step S703 in FIG. 7, it will be further described with reference to FIGS. 8 and 13 to 16. FIG. 13 shows the details of the first determination process 100, and FIG. 14 shows the details of the second determination process 200. FIG. 15 shows the change in the primary voltage detection signal when the ignition device has the first polarity corresponding to the changes in the detection signal and the detection counter. FIG. 16 shows the change in the primary voltage detection signal when the ignition device has the second polarity corresponding to the changes in the detection signal and the detection counter. In FIG. 13, the “+ signal determination process” executed when receiving from the threshold excess detection unit 22 the detection of the excess of the positive threshold voltage is shown as the first determination process 100. In FIG. 14, the “− signal determination process” executed when receiving from the threshold excess detection unit 22 the detection of the excess of the negative threshold voltage is shown as the second determination process 200. In FIGS. 15 and 16, the detection signal becomes “1” when the threshold excess detection unit 22 detects the excess of the threshold, and becomes “0” after a predetermined time has elapsed.

[0070] First, the case where the object to be determined is the ignition device with the first polarity shown in FIG. 15 will be described. At time point A when the primary voltage exceeds the positive threshold voltage “V T ”, the “+ detection signal” becomes “1”. When receiving from the threshold excess detection unit 22 the detection of the excess of the positive threshold voltage, the polarity determination unit 23 starts the polarity determination process in FIG. 8. The polarity determination unit 23 determines that it has received the detection of the excess of the positive threshold voltage (step S801: Yes) and executes the first determination process 100 in FIG. 13.

[0071] In the first determination process 100 shown in FIG. 13, it is determined whether the polarity is undetermined (step S1301). Since it is undetermined (step S1301: Yes), the “+ detection counter” is incremented from “1” to “2” (step S1302), and it is determined whether the “+ detection counter” is “4” (step S1303). At time point A, since the “+ detection counter” is “2” (step S1303: No), the first determination process 100 ends.

[0072] Also, when the primary voltage exceeds the negative threshold voltage "-V T " at time point B and the "-detection signal" becomes "1", and upon receiving the detection of the excess of the negative threshold voltage from the threshold-exceeding detection unit 22, the polarity determination unit 23 starts the polarity determination process of FIG. 8. The polarity determination unit 23 determines that it is not the case that the received value exceeds the positive threshold voltage (step S801: No), and executes the second determination process 200 of FIG. 14.

[0073] In the second determination process 200 shown in FIG. 14, it is determined whether the polarity is undetermined (step S1401). Since it is undetermined (step S1401: Yes), the "-detection counter" is incremented from "1" to "2" (step S1402), and it is determined whether the "-detection counter" is "4" (step S1403). At time point B, since the "-detection counter" is "2" (step S1403: No), the second determination process 200 ends.

[0074] Furthermore, when the primary voltage exceeds the positive threshold voltage "V T " at time point F and the "+detection signal" becomes "1", and upon receiving the detection of the excess of the positive threshold voltage from the threshold-exceeding detection unit 22, the polarity determination unit 23 executes the first determination process 100 of FIG. 13 according to the determination (Yes) in step S801 of FIG. 8. In the first determination process 100 of FIG. 13, it is determined whether the polarity is undetermined (step S1301). Since it is undetermined (step S1301: Yes), the "+detection counter" is incremented from "3" to "4" (step S1302), and it is determined whether the "+detection counter" is "4" (step S1303). At time point F, since the "+detection counter" is "4" (step S1303: Yes), it is further determined whether the value of the "+counter" is twice or more the value of the "-counter" (step S1304). At time point F, the value of the "+counter" is "4", and the value of the "-counter" is twice that of "2" (step S1304: Yes), so it is determined that the ignition device has the first polarity (step S1305), and the first determination process 100 ends.

[0075] Next, a case where the discrimination target is the ignition device of the second polarity shown in FIG. 16 will be described. When the primary voltage exceeds the negative threshold voltage "-V" at point A, the "-detection signal" becomes "1", and upon receiving the detection of the excess of the negative threshold voltage from the threshold excess detection unit 22, the polarity discrimination unit 23 executes the second discrimination process 200 of FIG. 14 according to the determination (No) in step S801 of FIG. 8. In the second discrimination process 200, it is determined whether the polarity is undetermined (step S111). Since it is undetermined (step S1401: Yes), the "-detection counter" is incremented from "1" to "2" (step S1402), and it is determined whether the "-detection counter" is "4" (step S1403). At point A, since the "-detection counter" is "2" (step S1403: No), the second discrimination process 200 ends. T At the time point A when the primary voltage exceeds the negative threshold voltage "-V", the "-detection signal" becomes "1", and upon receiving the detection of the excess of the negative threshold voltage from the threshold excess detection unit 22, the polarity discrimination unit 23 executes the second discrimination process 200 of FIG. 14 according to the determination (No) in step S801 of FIG. 8. In the second discrimination process 200, it is determined whether the polarity is undetermined (step S111). Since it is undetermined (step S1401: Yes), the "-detection counter" is incremented from "1" to "2" (step S1402), and it is determined whether the "-detection counter" is "4" (step S1403). At point A, since the "-detection counter" is "2" (step S1403: No), the second discrimination process 200 ends.

[0076] Also, at time point B, when the primary voltage exceeds the positive threshold voltage "V" at time point B, the "+detection signal" becomes "1", and upon receiving the detection of the excess of the positive threshold voltage from the threshold excess detection unit 22, the polarity discrimination unit 23 executes the first discrimination process 100 of FIG. 13 according to the determination (Yes) in step S801 of FIG. 8. In the first discrimination process 100 of FIG. 13, it is determined whether the polarity is undetermined (step S1301). Since it is undetermined (step S1301: Yes), the "+detection counter" is incremented from "1" to "2" (step S1302), and it is determined whether the "+detection counter" is "4" (step S1303). At time point B, since the "+detection counter" is "2" (step S1303: No), the first discrimination process 100 ends. T At the time point B when the primary voltage exceeds the positive threshold voltage "V", the "+detection signal" becomes "1", and upon receiving the detection of the excess of the positive threshold voltage from the threshold excess detection unit 22, the polarity discrimination unit 23 executes the first discrimination process 100 of FIG. 13 according to the determination (Yes) in step S801 of FIG. 8. In the first discrimination process 100 of FIG. 13, it is determined whether the polarity is undetermined (step S1301). Since it is undetermined (step S1301: Yes), the "+detection counter" is incremented from "1" to "2" (step S1302), and it is determined whether the "+detection counter" is "4" (step S1303). At time point B, since the "+detection counter" is "2" (step S1303: No), the first discrimination process 100 ends.

[0077] Furthermore, when the primary voltage is the negative threshold voltage "V" TWhen at time point F beyond 」, the 「-detection signal」 becomes 「1」, and upon receiving the detection of the exceeding of the negative threshold voltage from the threshold exceeding detection unit 22, the polarity discrimination unit 23 executes the second discrimination process 200 of FIG. 14 according to the determination (No) in step S801 of FIG. 8. In the second discrimination process 200 of FIG. 14, it is determined whether the polarity is undetermined (step S1401). Since it is undetermined (step S1401: Yes), the 「-detection counter」 is incremented from 「3」 to 「4」 (step S1402), and it is determined whether the 「-detection counter」 is 「4」 (step S1403). At time point F, since the 「-detection counter」 is 「4」 (step S1403: Yes), it is further determined whether the value of the 「-counter」 is more than twice the value of the 「+counter」 (step S1404). At time point F, since the value of the 「-counter」 is 「4」 and the value of the 「+counter」 is twice that of 「2」 (step S1404: Yes), it is determined that the ignition device has the second polarity (step S1405), and the second discrimination process 200 is terminated.

[0078] The polarity discrimination unit 23 executes step S703 by the above method, determines whether the discrimination is completed in step S704 (see FIG. 7), and executes the subsequent predetermined process shown in FIG. 7.

[0079] Thus, also by the discrimination method of the polarity discrimination device of the ignition device of the second embodiment, the polarity of the ignition device connected to the flywheel can be accurately discriminated. (Third Embodiment) This embodiment is the same as the second embodiment except that only the discrimination method in the polarity discrimination unit 23 is different from the first embodiment. In the third embodiment, it discriminates based on the time interval between adjacent timings among a plurality of timings when the primary voltage detection signals V11 and V12 are detected to have exceeded the threshold voltage. Since the other configurations are the same as those of the first embodiment, the description of the same parts is omitted, and only the different parts will be described.

[0080] The polarity discrimination unit 23 is such that in the threshold exceeding detection unit 22, the primary voltage detection signals V11 and V12 are the positive threshold voltage 「V TOf the plurality of timings at which it is detected that the value has exceeded "", the time interval between adjacent timings or the negative threshold voltage "-V T is determined based on the time interval between adjacent timings among the plurality of timings at which it is detected that the value has exceeded "". In the example shown in FIG. 6, while the time intervals of the timings at which it is detected that the positive threshold voltage "V T has been exceeded repeat "t1" and "t2", if the time interval of the timing at which it is detected that the negative threshold voltage "-V T has been exceeded is constant at "t3", it is determined that the pattern is (a), and it can be determined that the polarity is the first polarity. Similarly, while the time interval of the timing at which it is detected that the positive threshold voltage "V T has been exceeded is constant at "t3", if the time intervals of the timings at which it is detected that the negative threshold voltage "-V T has been exceeded repeat "t1" and "t2", it is determined that the pattern is (b), and it can be determined that the polarity is the second polarity.

[0081] Regarding the process of determining the polarity that the polarity determination unit 23 in the third embodiment executes as step S703 in FIG. 7, it will be further described based on FIGS. 8 and 17 to 20. FIG. 17 shows the details of the first determination process 100, and FIG. 18 shows the details of the second determination process 200. FIG. 19 shows the change in the primary voltage detection signal when the ignition device has the first polarity, corresponding to the detection signal and the time interval of the detection timing. FIG. 20 shows the change in the primary voltage detection signal when the ignition device has the second polarity, corresponding to the detection signal and the time interval of the detection timing. In FIG. 17, the "+ signal determination process" executed when receiving from the threshold exceedance detection unit 22 that the exceedance of the positive threshold voltage has been detected is shown as the first determination process 100, and in FIG. 18, the "- signal determination process" executed when receiving from the threshold exceedance detection unit 22 that the exceedance of the negative threshold voltage has been detected is shown as the second determination process 200. In FIGS. 19 and 20, the detection signal becomes "1" when the threshold exceedance detection unit 22 detects the threshold exceedance, and becomes "0" after a predetermined time has elapsed.

[0082] First, a case where the object to be discriminated is the ignition device of the first polarity shown in FIG. 19 will be described. When the primary voltage exceeds the positive threshold voltage "V T " at time point A, the "+ detection signal" becomes "1". When receiving the detection of the excess of the positive threshold voltage from the threshold excess detection unit 22, the polarity discrimination unit 23 starts the polarity discrimination process of FIG. 8. The polarity discrimination unit 23 determines that it has received the excess of the positive threshold voltage (step S801: Yes) and executes the first determination process 100 of FIG. 17.

[0083] In the first determination process 100 shown in FIG. 17, it is determined whether the polarity is undetermined (step S1701). Since it is undetermined (step S1701: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1702). The latest interval measurement result in the first determination process 100 is the elapsed time from the timing when the previous first determination process 100 was executed to the timing when the current first determination process 100 is executed (that is, the adjacent timing when the first determination process 100 is executed). In the example shown in FIG. 19, since the measurement has just started at time point A, the latest interval measurement result cannot be obtained.

[0084] Next, it is determined whether the latest interval measurement result obtained in S1702 is twice the previous interval measurement result (step S1703). At time point A, since the measurement of the interval has just started and the measurement result cannot be obtained (step S1703: No), the first determination process 100 ends.

[0085] Also, when the "- detection signal" becomes "1" at time point B where the primary voltage exceeds the negative threshold voltage "-V T " and the threshold excess detection unit 22 receives the detection of the excess of the negative threshold voltage, the polarity discrimination unit 23 starts the polarity discrimination process of FIG. 8. The polarity discrimination unit 23 determines that what it has received is not the excess of the positive threshold voltage (step S801: No) and executes the second determination process 200 of FIG. 18.

[0086] In the second determination process 200 shown in FIG. 18, it is determined whether the polarity is undetermined (step S1801). Since it is undetermined (step S1801: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1802). The latest interval measurement result in the second determination process 200 is the elapsed time from the timing when the previous second determination process 200 was executed to the timing when the current second determination process 200 is executed (that is, the adjacent timing when the second determination process 200 is executed). In the example shown in FIG. 19, since the measurement has just started at time point B, the latest interval measurement result cannot be obtained.

[0087] Next, it is determined whether the latest interval measurement result obtained in S1802 is twice the previous interval measurement result (step S1803). At time point B, the interval measurement has just started and the measurement result cannot be obtained (step S1803: No), so the second determination process 200 ends.

[0088] When the primary voltage exceeds the positive threshold voltage "V T " at time point D and the "+ detection signal" becomes "1" and the threshold - exceeding detection unit 22 receives the detection of the excess of the positive threshold voltage, the polarity discrimination unit 23 executes the first determination process 100 of FIG. 17 according to the determination (Yes) in step S801 of FIG. 8. In the first determination process 100 of FIG. 17, it is determined whether the polarity is undetermined (step S1701). Since it is undetermined (step S1701: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1702). The latest interval acquired in step S1702 at time point D is the interval measurement result t2 from the start of measurement at time point C to time point D.

[0089] Next, it is determined whether the latest interval measurement result t2 obtained in S1702 is twice the previous interval measurement result t1 (step S1703). At time point D, since the measurement result t2 of the latest interval is twice the measurement result t1 of the previous interval (step S1703: Yes), it is determined that the ignition device has the first polarity, and the first determination process 100 ends.

[0090] Next, the case where the discrimination target is the ignition device with the second polarity shown in FIG. 20 will be described. At the time point A when the primary voltage exceeds the negative threshold voltage "-V" T when the "-detection signal" becomes "1" and it is received that the negative threshold voltage has been detected by the threshold - exceeding detection unit 22, the polarity discrimination unit 23 executes the second determination process 200 of FIG. 18 according to the determination (No) in step S801 of FIG. 8. In the second determination process 200 of FIG. 18, it is determined whether the polarity is undetermined (step S1801). Since it is undetermined (step S18011: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1802). In the example shown in FIG. 20, since the measurement has just started at time point A, the latest interval measurement result cannot be obtained.

[0091] Next, it is determined whether the latest interval measurement result obtained in S1802 is twice the previous interval measurement result (step S1803). At time point A, since the measurement of the interval has just started and the measurement result cannot be obtained (step S1803: No), the first determination process 100 ends.

[0092] Also, when the primary voltage is the positive threshold voltage "V" TWhen at time point B beyond 「」, the 「+ detection signal」 becomes 「1」, and upon receiving the detection of the exceeding of the positive threshold voltage from the threshold exceeding detection unit 22, the polarity determination unit 23 executes the first determination process 100 of FIG. 17 according to the determination (Yes) in step S801 of FIG. 8. In the first determination process 100 of FIG. 17, it is determined whether the polarity is undetermined (step S1701). Since it is undetermined (step S1701: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1702). In the example shown in FIG. 20, since the measurement has just started at time point B, the latest interval measurement result cannot be obtained.

[0093] Next, it is determined whether the latest interval measurement result obtained in S1702 is twice the previous interval measurement result (step S1703). At time point B, since the measurement of the interval has just started and the measurement result cannot be obtained (step S1703: No), the first determination process 100 ends.

[0094] When the primary voltage exceeds the negative threshold voltage 「-V T 」 at time point D, the 「- detection signal」 becomes 「1」, and upon receiving the detection of the exceeding of the negative threshold voltage from the threshold exceeding detection unit 22, the polarity determination unit 23 executes the second determination process 200 of FIG. 18 according to the determination (No) in step S801 of FIG. 8. In the second determination process 200 of FIG. 18, it is determined whether the polarity is undetermined (step S1801). Since it is undetermined (step S1801: Yes), the latest interval measurement result is acquired and the measurement of the next interval is started (step S1802). The latest interval acquired in step S1802 at time point D is the interval measurement result t2 from the start of measurement at time point C to time point D.

[0095] Next, it is determined whether or not the latest interval measurement result t2 obtained in S1802 is twice the previous interval measurement result t1 (step S1803). At time point D, since the measurement result t2 of the latest interval is twice the measurement result t1 of the previous interval (step S1803: Yes), it is determined that the ignition device has the second polarity, and the second determination process 200 is terminated.

[0096] The polarity determination unit 23 executes step S703 by the above method, determines whether the determination is completed in step S704 (see FIG. 7), and executes the subsequent predetermined process shown in FIG. 7.

[0097] Thus, also by the determination method of the polarity determination device of the ignition device according to the third embodiment, the polarity of the ignition device connected to the flywheel can be accurately determined.

[0098] In the above embodiment, the polarity determination device of the ignition device includes the polarity switching unit 24. However, instead of the polarity switching unit 24, a warning unit that outputs a warning by sound, display, etc. when the polarity is incorrect in the case of the second polarity may be provided. By providing the warning unit, it is possible to prompt the ignition device to be switched to the correct polarity.

Explanation of Signs

[0099] 1 Engine 2 Electronic Control Unit (ECU) 100 Crankcase 101 First Cylinder 102 Second Cylinder 103 Crankshaft 104, 105 Intake Manifold 106 Throttle Body 107, 108 Exhaust Manifold 109 Flywheel INJ Injector (Fuel Injection Valve) THV Throttle Valve PL1 First Spark Plug PL2 Second Spark Plug M Magnet Rotor IU1 First Ignition Device IU2 Second Ignition Device

Claims

1. A primary voltage acquisition unit that acquires a primary voltage generated in an ignition coil of an external magnetic TCI ignition device that ignites an engine at an ignition timing corresponding to the rotation of a flywheel; A threshold exceedance detection unit that detects that the acquired primary voltage has exceeded a threshold voltage; Based on the pattern of exceedance detection, which is the pattern of detection in the threshold exceedance detection unit, a polarity determination unit that determines whether the ignition device is attached to the flywheel with either a first polarity in which a positive voltage occurs as the primary voltage at the ignition timing or a second polarity in which a negative voltage occurs as the primary voltage at the ignition timing. A polarity determination device for an ignition device.

2. The polarity determination unit determines, based on the fact that in the threshold exceedance detection unit, the acquired primary voltage has continuously exceeded either a positive threshold voltage or a negative threshold voltage, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity. The polarity determination device for an ignition device according to Claim 1.

3. The polarity determination unit determines, based on the number of times the acquired primary voltage has been detected as exceeding the positive threshold voltage and the number of times the acquired primary voltage has been detected as exceeding the negative threshold voltage in the threshold exceedance detection unit, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity. The polarity determination device for an ignition device according to Claim 1.

4. The polarity determination unit determines, based on the time interval between adjacent timings among a plurality of timings when the acquired primary voltage has been detected as exceeding the positive threshold voltage and the time interval between adjacent timings among a plurality of timings when the acquired primary voltage has been detected as exceeding the negative threshold voltage in the threshold exceedance detection unit, whether the ignition device is attached to the flywheel with either the first polarity or the second polarity. The polarity determination device for an ignition device according to Claim 1.

5. The polarity determination device according to any one of Claims 1 to 4, further comprising a polarity switching unit that switches the polarity of the primary voltage when it is determined that the polarity is the second polarity in the polarity determination unit.

6. The polarity discrimination device according to any one of claims 1 to 4, further comprising a warning unit that outputs a warning when it is discriminated in the polarity discrimination unit that the polarity is the second polarity.

7. A polarity discrimination device according to any one of claims 1 to 6, a spark plug connected to the secondary coil of the ignition device, a magnetic rotor installed on the flywheel, and an engine control device that controls the engine, characterized by comprising a rotation detection system.

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