Engine signal generator

Abstract

Provided is a signal generating device for an engine, comprising: a rotation sensor that is configured so as to output a signal each time a change in magnetic flux is detected, and that is fixed to a case of an engine; and a rotor provided with a reluctor for causing a change to occur in the magnetic flux detected by the rotation sensor each time the rotation position of a crankshaft matches a set rotation position. The signal generating device for an engine causes a signal to be outputted from the rotation sensor each time the rotation position of the crankshaft matches the set position. The reluctor is provided so that in one rotation of the crankshaft, a first signal pair comprising two signals generated successively with a first polarity and a second signal pair comprising two signals generated successively with a second polarity are generated once each from the rotation sensor.

Description

[Technical Field]

[0001] The present invention relates to a signal generating device for an engine that generates a signal containing information about the rotational position of the crankshaft of the engine. [Background technology]

[0002] To operate an engine (internal combustion engine), it is necessary to control the ignition operation and fuel injection operation for each cylinder of the engine. When performing these controls, information on the rotational position of the engine crankshaft is required. Information on the rotational position of the crankshaft may also be required when controlling the load driven by the engine.

[0003] To obtain information about the rotational position of an engine crankshaft, a signal generator is used that generates a signal synchronized with the rotation of the crankshaft. A common type of signal generator generates a signal when it detects a change in magnetic flux. This type of signal generator is composed of a rotation sensor that is fixed to the engine case and generates a signal when it detects a change in magnetic flux, and a rotor that rotates with the engine crankshaft and is equipped with a reluctor that causes a change in the magnetic flux detected by the rotation sensor every time the rotational position of the crankshaft coincides with a set position. The waveform of the signal generated by the signal generator is typically a pulse waveform, but it can also be a square wave or a step-like waveform.

[0004] The rotor has a cylindrical surface that shares a central axis with the crankshaft, and the cylindrical surface is provided with a reluctor that causes a change in the magnetic flux detected by the rotation sensor. The reluctor consists of a protrusion or recess formed on the cylindrical surface of the rotor, and when the rotor passes the position of the magnetic pole of the rotation sensor during rotation, it causes a change in the magnetic flux detected by the rotation sensor.

[0005] The rotation sensor includes a magnetic pole portion facing the area of ​​the rotor where the reluctor is formed across a gap, a magnet that causes magnetic flux to flow in a magnetic path including the magnetic pole portion and the area of ​​the rotor where the reluctor is formed, and a signal generating portion that generates a positive or negative signal every time the reluctor causes a change in the magnetic flux flowing in the magnetic path as the rotor rotates. The signal generating portion generates a positive or negative signal in synchronization with rotation of the crankshaft as a signal containing information about the rotational position of the crankshaft.

[0006] In order to obtain the information on the rotational position of the crankshaft required for engine control using this type of signal generating device, it is necessary to determine at which rotational position of the crankshaft each signal output by the rotation sensor was generated.

[0007] For example, when controlling the ignition operation of an engine, the rotational position of the crankshaft suitable for igniting the engine is set as the ignition position, and this ignition position is calculated in relation to the engine rotational speed.When the calculated ignition position is detected, an ignition command is given to the engine's ignition device to perform the ignition operation.

[0008] Normally, when controlling the ignition position of each cylinder of an engine, a reference position of the crankshaft is set at a position that is advanced by a certain angle from the top dead center position, which is the rotational position of the crankshaft when the piston of each cylinder of the engine reaches top dead center, and the time required for the crankshaft to rotate from the reference position to the ignition position is used as the ignition position measurement time and is calculated for various control conditions.

[0009] The control device for controlling the engine determines the signal generated at the reference position from among the multiple signals generated by the signal generator as the reference signal, and when the reference signal is determined, sets the ignition position measurement time in a timer and starts measurement. When the timer completes measurement of the set ignition position measurement time, the control device issues an ignition command to the ignition device to perform ignition operation.

[0010] In order to improve engine startability, it is preferable to send an ignition command signal to the ignition device as soon as the signal generator generates a specific signal after the engine starting operation has begun, without waiting until the control device is ready to control the engine ignition, thereby causing the initial combustion to occur as quickly as possible. In this case, the signal generator must be configured to generate a specific signal at a rotational position of the crankshaft that is suitable as the ignition position when the engine is started.

[0011] When an engine has multiple cylinders, the ignition and fuel injection operations of the engine must be controlled for each cylinder, and so the signal generator generates signals corresponding to each of the multiple cylinders of the engine. In this case, in order to control the ignition and fuel injection operations of each cylinder of the engine, it is necessary to determine at which rotational position of the crankshaft each signal generated by the signal generator corresponds to which cylinder.

[0012] A typical example of a signal generator for an engine is configured to alternately generate positive and negative signals in synchronization with the rotation of the crankshaft. When using a signal generator of this type, it is not possible to determine at which rotation position of the crankshaft each signal generated by the signal generator was generated, so a separate means must be provided to enable signal discrimination.

[0013] For this reason, as shown in Patent Document 1, a method has been adopted in which a cylinder discrimination device is separately provided to output cylinder discrimination signals corresponding to each cylinder in synchronization with the rotation of the engine camshaft, and signals output by a signal generating device while the cylinder discrimination signals corresponding to each cylinder are being generated are discriminated as signals corresponding to each cylinder.However, when using this method, it is necessary to provide a means for generating signals for discriminating signals in addition to the signal generating device that generates signals in synchronization with the rotation of the crankshaft, which inevitably makes the engine structure complicated.

[0014] Therefore, it has been proposed to include a pair of signals of the same polarity that are generated consecutively at a specific rotational position of the crankshaft among the multiple signals output by the rotation sensor during one rotation of the crankshaft, as shown in Patent Document 2. In the signal generating device shown in Patent Document 2, some reluctors provided on the rotor are shaped with a stepped portion, thereby generating two signals of the same polarity consecutively at positions that have a predetermined phase relationship with respect to the reference position of a specific cylinder.

[0015] As shown in Patent Document 2, if a pair of successively generated signals of the same polarity are included among the multiple signals output by a signal generating device, the later-generated signal of the same polarity can be determined to be the signal generated at a specific rotational position of the crankshaft, for example, the rotational position when the piston of a specific cylinder reaches top dead center. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Publication No. 11-229946 [Patent Document 2] Japanese Patent Application Publication No. 4-103856 Summary of the Invention [Problem to be solved by the invention]

[0017] As with the signal generator shown in Patent Document 2, if a number of output signals in which signals of different polarities alternate are included that contain unique signals that occur consecutively with the same polarity, it is possible to use the uniqueness of these signals to determine at which rotational position of the crankshaft each signal generated by the signal generator was generated.

[0018] However, when using the signal generator disclosed in Patent Document 2, if the crankshaft begins to rotate while the intermediate portion of the stepped reluctor faces the magnetic pole portion of the rotation sensor at engine start, it is necessary to rotate the crankshaft at least one full rotation before generating a continuous signal of the same polarity. As a result, there is a problem that, when starting the engine, there is a delay in obtaining the rotational position information necessary to enable engine start, which can prevent the engine from starting quickly. This is particularly problematic for engines that are started manually or by kickstarting.

[0019] Furthermore, while the engine is running, it is necessary to continuously distinguish between the signals generated by the signal generator. However, when the signal generator shown in Patent Document 2 is used, the signal of the same polarity used for distinguishing between signals can only be generated once per revolution of the crankshaft, which limits the speed at which signals can be distinguished.

[0020] An object of the present invention is to provide an engine signal generating device that can more quickly distinguish the signal output by the rotation sensor than conventional devices when obtaining rotational position information of the crankshaft using the device, which includes a rotation sensor fixed to an engine case and configured to output a signal each time a change in magnetic flux is detected, and a rotor that is arranged to rotate with the crankshaft of the engine and has a reluctor that causes the magnetic flux detected by the rotation sensor to change in one direction or the other each time the rotation position matches a set rotation position, so that when the reluctor changes the magnetic flux in one direction, the rotation sensor outputs a signal of a first polarity, and when the reluctor changes the magnetic flux in the other direction, the rotation sensor outputs a signal of a second polarity. [Means for solving the problem]

[0021] The present invention is applicable to a signal generating device for an engine, which includes a rotation sensor configured to output a signal each time a change in magnetic flux is detected and disposed in a fixed state relative to an engine case, and a rotor provided to rotate with the engine crankshaft and equipped with a reluctor that causes the magnetic flux detected by the rotation sensor to change in one direction or the other each time the rotational position of the crankshaft matches a set rotational position, wherein the device is configured so that when the reluctor changes the magnetic flux in one direction, the rotation sensor outputs a signal of a first polarity, and when the reluctor changes the magnetic flux in the other direction, the rotation sensor outputs a signal of a second polarity.

[0022] In the engine signal generating device according to the present invention, the reluctor is provided so that the rotor has one first magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change in one direction twice in succession as the rotor rotates, and one second magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change in the other direction twice in succession as the rotor rotates.

[0023] By providing a reluctor in this manner, when two signals generated successively by the rotation sensor are viewed as a signal pair, the signals output by the rotation sensor during one rotation of the rotor include one first signal pair of the same polarity consisting of two signals generated successively with a first polarity, and one second signal pair of the same polarity consisting of two signals generated successively with a second polarity.

[0024] With the signal generator configured as described above, after the engine start operation is initiated, the polarities of the signals sequentially output by the signal generator are monitored. When two signals having the same polarity are successively detected, it is possible to determine at which rotational position of the crankshaft the last-detected signal of these two signals was generated. Because the first same-polarity signal pair and the second same-polarity signal pair are each generated only once per rotor rotation, it is possible to immediately determine at which rotational position of the crankshaft the signals constituting each signal pair were generated when each signal pair is detected, thereby enabling rapid determination of the rotational position of the crankshaft. Furthermore, because the signals constituting the first same-polarity signal pair and the signals constituting the second same-polarity signal pair have different polarities, the two signal pairs can be clearly distinguished and recognized.

[0025] In one aspect of the present invention, the reluctor is provided so that the group of signal pairs output by the rotation sensor during one rotation of the rotor includes only a first same-polarity signal pair consisting of two signals that have a first polarity and are generated successively, a first opposite-polarity signal pair consisting of two signals, one of the first polarity and one of the second polarity, a second same-polarity signal pair consisting of two signals that have a second polarity and are generated successively, and a second opposite-polarity signal pair consisting of two signals, one of the second polarity and one of the first polarity, that are generated successively.

[0026] With this configuration, it is possible to make all of the polarity combinations of the two signals output in succession by the rotation sensor during one rotation of the rotor different, so that it is possible to immediately determine at which rotational position each signal was generated from the polarity of the two signals output in succession by the rotation sensor, and to accurately and quickly obtain information on the rotational position of the crankshaft.

[0027] In another aspect of the present invention, a reluctor is provided so that the group of signal pairs output by the rotation sensor during one rotation of the rotor consists solely of a first same-polarity signal pair consisting of two successively generated signals of a first polarity, a first opposite-polarity signal pair consisting of two successively generated signals of a first polarity and a second polarity, a second same-polarity signal pair consisting of two successively generated signals of a second polarity, a second opposite-polarity signal pair consisting of two successively generated signals of a second polarity and a first polarity signal, and a third opposite-polarity signal pair consisting of two successively generated signals of a first polarity and a second polarity signal.

[0028] The signal generated by the signal generating device may be any signal whose level changes at a specific rotational position of the engine crankshaft. In this specification, the polarity of a signal is represented by the direction of the level change when the signal is generated. For example, if each signal has a pulse waveform, the polarity is defined as positive if the direction of the level change when the signal is generated is positive, and as negative if the direction of the level change when the signal is generated is negative. If a signal has two different polarities, it is arbitrary which polarity is defined as positive and which polarity is defined as negative.

[0029] The waveform of the signal generated by the signal generating unit may be a pulse waveform, or may be a rectangular or stepped waveform. When the waveform of the signal generated by the signal generating unit is a rectangular or stepped waveform, the rising and / or falling edges of the signal are recognized as signals containing information about the rotational position of the crankshaft. In this case, for example, the rising edge of the signal level is considered to be a positive signal, and the falling edge of the signal level is considered to be a negative signal. The first polarity and the second polarity are mutually opposite, and when the first polarity is positive, the second polarity is negative, and when the first polarity is negative, the second polarity is positive.

[0030] As described above, in a conventional signal generator that generates a signal pair consisting of two consecutive signals of the same polarity only once per rotation of the crankshaft, depending on the rotational position of the crankshaft when the engine start operation is initiated, it is necessary to rotate the crankshaft more than one rotation to obtain the rotational position information of the crankshaft necessary to enable engine start. As a result, there is a delay in obtaining the rotational position information of the crankshaft necessary to enable engine start, which can result in poor engine startability.

[0031] In contrast, according to the present invention, regardless of the position from which the crankshaft begins to rotate when the engine is started, it is possible to always generate, during one rotation of the engine, either a first same-polarity signal pair consisting of two signals generated sequentially with a first polarity or a second same-polarity signal pair consisting of two signals generated sequentially with a second polarity, thereby quickly obtaining information on the rotational position of the crankshaft necessary to enable engine starting, thereby improving engine startability.

[0032] The present invention can be implemented in various forms, and further forms of the present invention will become apparent from the following description of the preferred embodiments of the invention. [Effects of the Invention]

[0033] According to the present invention, regardless of the position from which the crankshaft begins to rotate when the engine is started, either the first pair of signals of the same polarity or the second pair of signals of the same polarity can be generated during one rotation of the engine, so that crankshaft rotational position information can be quickly obtained when the engine is started, thereby improving the startability of the engine.

[0034] Furthermore, after the engine has started, two signal pairs, a first signal pair of the same polarity and a second signal pair of the same polarity, are generated during one rotation of the crankshaft, and the location where each signal originates can be determined based on both signal pairs. This increases the opportunities to determine the location where each signal originates, thereby improving the reliability of determining the location where the signal originates.

[0035] Furthermore, according to the present invention, there is no need to provide a separate device for generating a signal that enables the position at which the signal is generated to be determined, which prevents the engine structure from becoming complicated.

[0036] In particular, in the present invention, if the reluctor is formed using only reluctor components consisting of the first through third sections aligned circumferentially of the rotor, the first magnetic flux change generator is formed using a section configuration at the leading end of the first section and a section configuration at the junction between the rear end of the first section and the leading end of the second section, and the second magnetic flux change generator is formed using a section configuration at the junction between the rear end of the second section and the leading end of the third section and a third section configuration at the rear end of the third section, the combinations of polarities of the two signals constituting each of all signal pairs detected during one rotor rotation can be made different, so that, regardless of the position from which the rotor starts rotating, the position at which the second signal of the first and second signals constituting the signal pair is generated can be immediately determined when a signal pair consisting of two successively generated signals is first detected. Therefore, crankshaft rotational position information can be obtained in the shortest time immediately after the engine start operation is initiated. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a front view showing a schematic configuration of an embodiment of a signal generating device according to the present invention. [Figure 2]FIG. 2(A) is an exploded view showing the shape of the reluctor provided on the outer periphery of the rotor of the signal generating device shown in FIG. 1 when viewed from the outer diameter side toward the inner diameter side of the rotor, and FIG. 2(B) is an exploded view showing the shape of the same reluctor when viewed from the direction along the axial direction of the rotor. [Figure 3] FIG. 3 is a development view showing the shape of a modified example of a reluctor provided on the rotor of the signal generating device shown in FIG. 1, as viewed in the direction from the outer diameter side to the inner diameter side of the rotor. [Figure 4] Figure 4(A) is an exploded view showing the shape of another modified example of a reluctor provided on the rotor of the signal generating device shown in Figure 1, when viewed from the outer diameter side of the rotor toward the inner diameter side. Figure 4(B) is an exploded view showing the shape of the reluctor of Figure 4(A) when viewed from the axial direction of the rotor. Figure 4(C) is a waveform diagram showing the waveform of a signal generated when each action point set on the reluctor passes through the position of the magnetic pole portion of the rotation sensor. [Figure 5] Fig. 5(A) is a side view showing a schematic configuration of a rotation sensor used in one embodiment of the present invention, and Fig. 5(B) is a cross-sectional view of the rotation sensor taken along line BB in Fig. 5(A). [Figure 6] Figure 6(A) is an exploded view showing the reluctor components to be provided on the rotor when the signal generating device shown in Figure 1 is applied to a single-cylinder engine, Figure 6(B) is a waveform diagram showing the signals generated by the signal generating device when the same rotor is used, and Figure 6(C) is a process diagram showing the processes performed in the engine cylinders when each signal shown in Figure 6(B) is generated. [Figure 7] Figure 7(A) is an exploded view showing the shape of a reluctor component to be provided on a rotor used when applying a signal generating device having the configuration shown in Figure 1 to a two-cylinder four-cycle engine, Figure 7(B) is a waveform diagram showing the waveform of a signal obtained when using the same rotor, and Figures 7(C) and (D) are process diagrams showing the process performed in the first cylinder #1 and the second cylinder #2 of the engine when each signal shown in Figure 7(B) is generated. [Figure 8]Figure 8(A) is an exploded view showing the shape of the reluctor components used in an embodiment in which the signal generating device having the configuration shown in Figure 1 is applied to a three-cylinder four-cycle engine, Figure 8(B) is a waveform diagram showing the waveform of the signal obtained when the same rotor is used, and Figures 8(C) to 8(E) are process diagrams showing the processes performed in the three cylinders #1 to #3 of the engine when each signal shown in Figure 8(B) is generated. [Figure 9] Figure 9(A) is an exploded view showing the shape of a reluctor used in an embodiment in which a signal generating device having the configuration shown in Figure 1 is applied to a four-cylinder four-cycle engine, Figure 9(B) is a waveform diagram showing the waveform of a signal obtained when a rotor equipped with the same reluctor is used, and Figures 9(C) to 9(F) are process diagrams showing the processes performed in the first to fourth cylinders #1 to #4 of the engine when each signal shown in Figure 9(B) is generated. [Figure 10] FIG. 10 is a front view schematically showing the configuration of another embodiment of a signal generating device according to the present invention. [Figure 11] FIG. 11(A) is a development view of the reluctor provided on the rotor shown in FIG. 10, and FIG. 11(B) is a waveform diagram showing the waveforms of a series of signals obtained from the signal coil of the rotation sensor when the same rotor is used. [Figure 12] FIG. 12 is a front view schematically showing the configuration of still another embodiment of a signal generating device according to the present invention. [Figure 13] Figure 13(A) is an exploded view showing the shape of a reluctor used in an embodiment in which a signal generating device having the configuration shown in Figure 12 is applied to a three-cylinder four-cycle engine, Figure 13(B) is a waveform diagram showing the waveform of a signal obtained from the signal coil of a rotation sensor when the same rotor is used, and Figures 13(C) to (E) are process diagrams showing the processes performed in three cylinders #1 to #3 of the three-cylinder engine when each signal shown in Figure 13(B) is generated. [Figure 14]Figure 14(A) is an exploded view showing the shape of a reluctor used in an embodiment in which a signal generating device having the configuration shown in Figure 12 is applied to a six-cylinder four-cycle engine, Figure 14(B) is a waveform diagram showing the waveform of a signal obtained when the same reluctor is used, and Figures 14(C) to (H) are process diagrams showing the process performed in the six cylinders of the six-cylinder engine when each signal shown in Figure 14(B) is generated. [Figure 15] FIG. 15(A) is a development view showing a modified example of the reluctor used in the present invention, and FIG. 15(B) is a waveform diagram showing the waveform of a signal obtained when a rotor equipped with the same reluctor is used. [Figure 16] FIG. 16(A) is a waveform diagram showing an example of the waveform of a detection signal obtained when the signal generating section of a rotation sensor is configured using a magnetic sensor, and FIG. 16(B) is a waveform diagram showing a pulse signal generated at each rising edge and each falling edge of the waveform shown in FIG. 16(A). [Figure 17] FIG. 17 is a flowchart showing an example of an algorithm for crank angle interrupt processing executed when determining the generation position of the signal generated by the signal generating device in the embodiment shown in FIG. [Figure 18] FIG. 18 is a flowchart showing an example of an algorithm for initial processing executed when determining the signal generated by the signal generating device in the embodiment shown in FIG. [Figure 19] FIG. 19 is a flowchart showing an example of an algorithm for the main determination process executed when determining the signal generated by the signal generating device in the embodiment shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0038] The signal generating device according to the present invention can be widely used in cases where it is necessary to obtain rotational position information of the crankshaft of an engine in order to control the engine or the load of the engine. The rotational position information of the crankshaft is information indicating that the rotational position of the crankshaft coincides with a specific rotational position.

[0039] In this specification, the term "specific rotational position" does not have a limiting meaning and may refer to various rotational positions of the crankshaft depending on the type of control performed on the engine or the load driven by the engine. When controlling the ignition position of an engine or the fuel injection position, the "specific rotational position" may be, for example, the rotational position of the crankshaft when measurement of the ignition position or the fuel injection position begins, or the rotational position of the crankshaft when initial ignition occurs during engine start-up.

[0040] In this specification, the rotational position of the crankshaft when the piston of each cylinder of the engine reaches top dead center is referred to as the top dead center position of each cylinder. Also, the rotational position of the crankshaft when starting to measure the ignition position of each cylinder calculated for various control conditions is referred to as the reference position of each cylinder. The rotational position of the engine crankshaft is also sometimes referred to as the crank angle position.

[0041] In one embodiment of the present invention, a signal generating device for an engine includes a rotation sensor fixed to an engine case and configured to output a signal each time a change in magnetic flux is detected, and a rotor arranged to rotate with the engine crankshaft and equipped with a reluctor that causes the magnetic flux detected by the rotation sensor to change in one direction or the other each time the rotation position matches a set rotation position, and when the reluctor changes the magnetic flux in one direction, a signal of a first polarity is output from the rotation sensor, and when the reluctor changes the magnetic flux in the other direction, a signal of a second polarity is output from the rotation sensor.

[0042] The rotor used in the signal generator to which the present invention is applied has a cylindrical surface that is arranged to share a central axis with the crankshaft when attached to the engine, and a reluctor is provided on this cylindrical surface. The rotation sensor also has a magnetic pole portion that faces the area of ​​the cylindrical surface of the rotor where the reluctor is provided across a gap, and a magnetic path that is formed to include this magnetic pole portion and the reluctor. Signal generating magnetic flux The magnet that flows the reluctor and the rotor rotates. Signal generating magnetic flux and a signal generating section for generating a signal indicating a level change each time a change is made to the input signal.

[0043] In a preferred embodiment of the present invention, the reluctor is configured to have one first magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change twice in one direction as the rotor rotates, and one second magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change twice in the other direction as the rotor rotates.

[0044] By configuring the reluctor in this manner, the series of signal pairs output by the rotation sensor during one rotation of the rotor can include one first signal pair of the same polarity consisting of two successively generated signals of a first polarity, and one second signal pair of the same polarity consisting of two successively generated signals of a second polarity.

[0045] In a preferred embodiment of the present invention, the reluctor is provided so that the group of signal pairs output by the rotation sensor during one rotation of the rotor includes only a first same-polarity signal pair consisting of two signals that have a first polarity and occur successively, a first opposite-polarity signal pair consisting of two signals, one of the first polarity and one of the second polarity, a second same-polarity signal pair consisting of two signals that have a second polarity and occur successively, and a second opposite-polarity signal pair consisting of two signals, one of the second polarity and one of the first polarity, that occur successively.

[0046] In another preferred embodiment of the present invention, a reluctor is provided so that the group of signal pairs output by the rotation sensor during one rotation of the rotor consists solely of a first same-polarity signal pair consisting of two successively generated signals of a first polarity, a first opposite-polarity signal pair consisting of two successively generated signals of a first polarity and a second polarity, a second same-polarity signal pair consisting of two successively generated signals of a second polarity, a second opposite-polarity signal pair consisting of two successively generated signals of a second polarity and a first polarity signal, and a third opposite-polarity signal pair consisting of two successively generated signals of a first polarity and a second polarity signal.

[0047] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Referring to Fig. 1, the configuration of one embodiment of a signal generating device 1 according to the present invention is shown in outline. The illustrated signal generating device 1 is attached to a crankshaft 2 of an engine and comprises a rotor 3 that is rotated together with the crankshaft, and a rotation sensor 4.

[0048] The rotation sensor 4 is attached to a rotation sensor attachment portion (not shown) provided on the engine case or a frame to which the engine is fixed, and is disposed in a fixed state relative to the engine case.

[0049] The rotation sensor 4 has a magnetic pole portion 4a that faces the magnetic pole surface of the rotor 3, and a magnetic path including the rotation sensor 4 and the magnetic pole surface of the rotor 3. Signal generating magnetic flux A magnet that flows Signal generating magnetic flux and a signal generating unit that detects the magnetic flux and generates a signal when a change occurs in the detected magnetic flux. The rotation sensor generates a signal of a first polarity when it detects that the signal-generating magnetic flux being detected has changed in one direction, and generates a signal of a second polarity when it detects that the signal-generating magnetic flux being detected has changed in the other direction. A change in the signal-generating magnetic flux is a change in the magnetic flux in an increasing or decreasing direction. For example, if a change in the signal-generating magnetic flux in an increasing direction is considered to be a change in the magnetic flux in one direction, a change in the signal-generating magnetic flux in a decreasing direction is considered to be a change in the magnetic flux in the other direction. Specific configuration examples of the rotation sensor 4 will be described later.

[0050] The rotor 3 includes a rotating body 301 attached to the crankshaft 2 of the engine. The rotating body 301 may be provided solely to constitute the rotor of the signal generator, or may also serve as the rotating body of another rotating device such as a generator. The rotating body 301 may be an engine accessory that is rotated together with the crankshaft 2, such as a flywheel attached to the engine crankshaft, or a pulley attached to the engine crankshaft and connected via a belt to an engine cooling fan.

[0051] In this embodiment, a flywheel attached to a crankshaft 2 is used as the rotating body 301. The illustrated rotating body 301 is formed in a cup shape with a cylindrical peripheral wall portion 301a and a bottom wall portion 301b that closes one axial end of the peripheral wall portion 301a. A boss portion 301c is formed in the center of the bottom wall portion 301b of the rotating body 301. The rotating body 301 is attached to the engine by fitting the boss portion 301c onto the crankshaft 2 of the engine and keying it to the crankshaft. A cylindrical surface 302 that concentrically surrounds the central axis O of the crankshaft 2 is formed on the outer periphery of the peripheral wall portion 301a of the rotating body 301. The peripheral wall portion 301a of the rotating body 301 also serves as the peripheral wall portion of the rotor, and the cylindrical surface 302 also serves as the cylindrical surface of the rotor. The cylindrical surface 302 also serves as the outer periphery of the rotor.

[0052] In this embodiment, the rotation direction of the crankshaft 2 during steady operation of the engine is defined as the forward rotation direction of the crankshaft. In Fig. 1, the forward rotation direction of the crankshaft is indicated by arrow R. In the following description, the direction along the central axis O of the cylindrical surface 302 of the rotor 3 (the direction perpendicular to the plane of the paper in Fig. 1) is defined as the width direction of the cylindrical surface 302.

[0053] At least a portion of the rotor 3 near the outer periphery, i.e., at least a portion of the rotor 301 near the outer periphery, is made of a ferromagnetic material such as iron, and a reluctor is provided on a cylindrical surface 302 formed on the outer periphery of the portion of the rotor 3 made of the ferromagnetic material. The reluctor is formed by a protrusion or recess extending circumferentially on the cylindrical surface 302 of the rotor. The reluctor has multiple points of application spaced apart circumferentially on the cylindrical surface 302. The reluctor exhibits changes in shape at each point of application, such as changes in width or protrusion height from the cylindrical surface 302. When each point of application passes the position of the magnetic pole portion 4a of the rotation sensor 4, the reluctor changes the distance between the rotor's magnetic pole surface MS and the magnetic pole portion 4a of the rotation sensor 4, or changes the area of ​​the rotor's magnetic pole surface MS facing the magnetic pole portion 4a of the rotation sensor 4, thereby changing the magnetic resistance between the rotor's magnetic pole surface MS and the magnetic pole portion 4a of the rotation sensor 4 and changing the signal-generating magnetic flux. This change in the signal generating magnetic flux causes the rotation sensor 4 to output a signal.

[0054] In this embodiment, the entire rotor 301 is made of a ferromagnetic material such as iron. As shown in Figures 2(A) and 2(B), a reluctor component 303 extending in the circumferential direction of the rotor 301 is provided in a region near the center in the width direction of a cylindrical surface 302 formed on the outer periphery of the rotor 301, with its leading end facing forward in the rotation direction R of the rotor and its rear end facing backward in the rotation direction of the rotor, and a reluctor is formed by this reluctor component.

[0055] In the illustrated example, the widest portion of reluctor element 303 has a width dimension smaller than the width dimension of rotor cylindrical surface 302. Therefore, flat regions where no reluctor is provided remain in portions near one end and the other end in the width direction of rotor cylindrical surface 302. In this embodiment, the outer peripheral surface of reluctor element 303 and the outer peripheral surface of rotor 301 exposed to the outside in the radial direction of rotor 301 between the leading end and trailing end of reluctor element 303 form the rotor's magnetic pole surface MS.

[0056] When controlling the engine, a signal generator generates a signal each time the rotational position of the crankshaft coincides with one of a plurality of preset rotational positions. To this end, a reluctor provided on the rotor is set with a plurality of application points. Each time each application point passes through the position of the magnetic pole portion 4a of the rotation sensor, a change occurs in the magnetic flux detected by the rotation sensor, causing the rotation sensor 4 to output a signal. The application points of the reluctor are set by gradually changing the shapes of the protrusions and recesses that make up the reluctor before and after the application point. In this embodiment, four signals are generated from the signal generator during one rotation of the crankshaft. To this end, first through fourth application points are set on the reluctor provided on the rotor. When the first through fourth application points of the reluctor pass through the position of the magnetic pole portion 4a of the rotation sensor 4, a change occurs in one direction or another in the magnetic flux detected by the rotation sensor 4. The rotation sensor 4 detects the changes in magnetic flux that occur when the first to fourth action points pass through the position of the magnetic pole portion 4a of the rotation sensor 4, and outputs the first signal Vs1 to the fourth signal Vs4 from the rotation sensor 4.

[0057] In order to determine the positions of the first to fourth points of action of the reluctor, first to fourth set positions P1 to P4 are set on the cylindrical surface of the rotor, aligned at predetermined intervals in the circumferential direction of the cylindrical surface, and the first to fourth points of action of the reluctor are set at the first to fourth set positions P1 to P4, respectively.

[0058] To explain in more detail, the illustrated reluctor component 303 comprises an arc-shaped first section S1 extending from a first set position P1 to a second set position P2 along the circumferential direction of the cylindrical surface 302 with a front end S1a facing forward in the rotation direction R of the rotor 3 and a rear end facing rearward in the rotation direction R of the rotor 3, an arc-shaped second section S2 extending from a second set position P2 to a third set position P3 along the circumferential direction of the cylindrical surface 302 with a front end S2a connected to a rear end S1b of the first section S1 and a rear end S2b facing rearward in the rotation direction R of the rotor 3, and a front end S3a connected to a rear end S2b of the second section S2 and a rear end S3b facing rearward in the rotation direction R of the rotor 3. Cylindrical surface and a third section S3 having an arc shape extending from the third set position P3 to the fourth set position P4 along the circumferential direction of the shaft 302. In this embodiment, the outer diameters of the first to third sections S1 to S3 are set equal, so that the outer peripheral surfaces of the first to third sections S1 to S3 are arranged on the same cylindrical surface.

[0059] 2(A) and 2(B), the first section S1 constituting the portion of the reluctor element 303 near the tip end has a constant thickness d and a constant first width dimension W1, and is provided so as to extend from a first set position P1 to a second set position P2 in the circumferential direction of the rotor 3. The first section S1 is provided with its tip S1a facing forward in the forward rotation direction R of the crankshaft 2, and the position of the tip S1a coincides with the first set position P1. The tip S1a of the first section S1 is also the tip of the reluctor element 303.

[0060] In this example, to set the first point of action at first set position P1, the tip S1a of first section S1 is raised at a right angle from cylindrical surface 302, which is the outer peripheral surface of the rotor, at first set position P1, and the height of first section S1 is increased in a step-like manner at first set position P1. When this first point of action passes the position of the magnetic pole portion of the rotation sensor during the rotor rotation process, the distance between the magnetic pole surface of the reluctor and magnetic pole portion 4a of rotation sensor 4 changes in a step-like manner in the direction of decreasing.

[0061] When the first point of application passes the position of the magnetic pole portion of the rotation sensor, the distance between the magnetic pole face of the reluctor and the magnetic pole portion of the rotation sensor 4 decreases, causing the magnetic flux detected by the rotation sensor 4 to increase. This change in magnetic flux causes the rotation sensor 4 to output a first signal having a first polarity.

[0062] While it is possible to determine in which direction a change in the magnetic flux detected by the rotation sensor is considered to be a unidirectional change, in this embodiment, a change in the magnetic flux detected by the rotation sensor 4 in an increasing direction is considered to be a unidirectional change in the magnetic flux. In addition, the polarity of the signal output by the rotation sensor 4 when the magnetic flux detected by the rotation sensor changes in an increasing direction is considered to be a first polarity.

[0063] The second section S2 constituting the middle part of the reluctor component 303 has the same thickness d as the first section S1, and has a constant second width dimension W2 larger than the first width dimension W1, and is arranged to extend in the circumferential direction of the rotor 3 from the second set position P2 to the third set position P3, with the leading end S2a of the second section S2 being connected to the rear end S1b of the first section S1 at the second set position P2.

[0064] Because the width dimension W2 of the second section is set larger than the width dimension W1 of the first section, the width dimension of the reluctor is expanded in a step-like manner at the second set position P2. As a result, a second point of application of the reluctor is set at the second set position P2, and when this second point of application passes the position of the magnetic pole portion of the rotation sensor during the rotor rotation process, the area of ​​the magnetic pole face of the reluctor that faces the magnetic pole portion of the rotation sensor is changed in a step-like manner in the increasing direction. Therefore, when the second point of application of the reluctor passes the position of the magnetic pole portion of the rotation sensor during the rotor rotation process, the magnetic flux detected by the rotation sensor changes again in the increasing direction, and the rotation sensor again outputs a signal of the first polarity.

[0065] The third section S3 constituting the portion of the reluctor component 303 near the rear end has the same thickness d as the first section S1 and the second section S2, and has a constant width dimension W3 smaller than the width dimension W2 of the second section S2, and is provided so as to extend from the third set position P3 to the fourth set position P4 in the circumferential direction of the rotor 3. The third section S3 is provided with its leading end S3a connected to the rear end S2b of the second section S2 and its rear end S3b facing rearward in the forward rotation direction R of the rotor.

[0066] By setting the width W3 of the third section S3 smaller than the width W2 of the second section S2, the width of the reluctor is reduced in a step-like manner at the third set position P3. As a result, the third point of application of the reluctor is set at the third set position P3. As the rotor rotates, when this third point of application passes the position of the magnetic pole portion of the rotation sensor, the area of ​​the rotor's magnetic pole face that faces the magnetic pole portion 4a of the rotation sensor decreases in a step-like manner.

[0067] Therefore, when the third point of application passes the position of the magnetic pole portion 4a of the rotation sensor during the rotation of the rotor, the magnetic flux detected by the rotation sensor changes in a decreasing direction, and the rotation sensor outputs a signal of the second polarity. In this embodiment, a change in the magnetic flux detected by the rotation sensor 4 in a decreasing direction is considered to be a change in the magnetic flux in the other direction, and the polarity of the signal output by the rotation sensor when the magnetic flux detected by the rotation sensor changes in a decreasing direction is considered to be the second polarity.

[0068] At rear end S3b of third section S3, the height of third section S3 measured from cylindrical surface 302 is lowered in a stepwise manner, thereby setting the fourth point of application of the reluctor at fourth set position P4. As the rotor rotates, when this fourth point of application passes the position of the magnetic pole portion of the rotation sensor, the distance between the magnetic pole portion of the rotation sensor and the magnetic pole surface of the rotor increases in a stepwise manner. Therefore, when the fourth point of application of the reluctor passes the position of the magnetic pole portion of the rotation sensor, the magnetic flux detected by the rotation sensor again decreases. The rotation sensor detects this change in magnetic flux and again outputs a signal of the second polarity.

[0069] In the drawings of the present application, the first to fourth points of action of the reluctor are not labeled with symbols, but the positions at which the first to fourth points of action are located correspond to the first set position P1 to the fourth set position P4, respectively, and therefore the positions at which each point of action is set can be identified from the symbols P1 to P4 indicating the first to fourth set positions.

[0070] The width dimension W3 of the third section S3 constituting the portion near the rear end of the reluctor component 303 may be smaller than the width dimension W2 of the second section S2. In this embodiment, the width dimension W3 of the third section S3 is set equal to the width dimension W1 of the first section S1.

[0071] In this embodiment, a first point of action set at the leading end S1a of the first section S1 of the reluctor element 303 and a second point of action set at the connecting portion between the rear end S1b of the first section S1 and the leading end S2a of the second section S2 constitute a first magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor 4 to change in one direction twice consecutively during the rotation of the rotor 3. This first magnetic flux change generating unit causes the magnetic flux detected by the rotation sensor 4 to change in one direction twice consecutively during one rotation of the rotor, and therefore causes the rotation sensor to output a first same-polarity signal pair consisting of two signals generated consecutively with a first polarity.

[0072] Furthermore, a third point of action set at the connection between the rear end S2b of the second section S2 of the reluctor element 303 and the front end S3a of the third section S3, and a fourth point of action set at the rear end S3b of the third section S3 of the first reluctor element 303A, constitute a second magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor 4 to change in the other direction twice consecutively during the rotation of the rotor. This second magnetic flux change generating unit causes the magnetic flux detected by the rotation sensor 4 to change in the other direction twice consecutively during one rotation of the rotor, and therefore causes the rotation sensor to output a second same-polarity signal pair consisting of two second-polarity signals that are generated consecutively with the second polarity.

[0073] Since the rotor 3 is provided with one first magnetic flux change generating unit and one second magnetic flux change generating unit, the rotation sensor 4 outputs a first signal pair of the same polarity and a second signal pair of the same polarity once per rotation of the rotor.

[0074] 1 and 2, the polar arc angles of the first to third sections are set so that the angular intervals between the first to fourth setting positions P1 to P4, i.e., the angular intervals between the first to fourth points of application, are 90 CA, but the angular intervals between the setting positions can be set appropriately depending on the application of the signal generator. CA here means crank angle.

[0075] In the example shown in Figures 1 and 2, the width dimension W2 of the second section S2 of the reluctor component is set larger than the width dimension W1 of the first section S1 and the width dimension W3 of the third section S3, thereby setting the second point of action and the third point of action at the second setting position P2 and the third setting position P3, respectively, but the reluctor component 303 used in the present invention is not limited to being configured in this manner.

[0076] For example, as shown in Figures 4(A) and (B), the first section S1 to the third section S3 may have the same constant width dimension W, and the thickness d2 of the second section S2 may be made thicker than the thickness d1 of the first section S1 and the thickness d3 of the third section S3, and the height of the reluctor components may be changed in a stepwise manner at the first set position P2 and the third set position P3, thereby setting the second point of action and the third point of action at the first set position P2 and the third set position P3, respectively.

[0077] Even when configured in this manner, as shown in Figure 4(C), when the first and second action points pass the position of the magnetic pole portion of the rotation sensor at the set rotation positions θ1 and θ2, the first signal Vs1 and the second signal Vs2 having the first polarity can be output from the rotation sensor, and when the third and fourth action points pass the position of the magnetic pole portion of the rotation sensor at the set rotation positions θ3 and θ4, the third signal Vs3 and the fourth signal Vs4 having the second polarity can be output from the rotation sensor.

[0078] 5(A) and (B), the configuration of the rotation sensor 4 used in this embodiment is shown. The rotation sensor 4, which constitutes the signal generating device 1 together with the rotor 3, includes a magnetic pole portion 4a that faces the magnetic pole face of the rotor 3 across a gap, a permanent magnet that causes magnetic flux to flow in a magnetic path formed to include the magnetic pole portion 4a and a reluctor formed on the magnetic pole face of the rotor, and a signal generating unit that generates a signal indicating a level change as a signal containing crank angle information each time the first reluctor 303A and the second reluctor 303B cause a change in the magnetic flux flowing in the magnetic path during the rotation of the rotor.

[0079] The illustrated rotation sensor 4 includes an iron core 401, a signal coil 402 wound around the iron core 401, a permanent magnet 403 that passes magnetic flux through the iron core 401, and a magnetic path component 404 made of a ferromagnetic material such as iron. In the illustrated example, the tip of the iron core 401 forms a magnetic pole portion 4a, which faces the magnetic pole faces MS of the first and second reluctor components 303A and 303B via an air gap.

[0080] The illustrated magnetic path component 404 includes a base plate 404a disposed perpendicular to the radial direction of the rotor 3, and a side plate 404b bent at a right angle from one end of the base plate 404a and extending toward the rotor 3. Ears 404c, 404c protruding in opposite directions are formed at the end of the side plate 404b closer to the base plate 404a. Mounting holes 404d, 404d are formed in the ears 404c, 404c. One magnetic pole (the south pole in the illustrated example) of the permanent magnet 403 is connected to the base plate 404a of the magnetic path component 404, and the rear end of the rotation sensor core 401 is connected to the other magnetic pole (the north pole in the illustrated example) of the permanent magnet 403.

[0081] The components of the rotation sensor 4 are arranged with the magnetic pole portion 4a exposed to the outside, and at least the portion of the side plate portion 404b of the magnetic path component 404 near the tip and the ear portions 404c, 404c exposed to the outside, by being covered with a molded portion made of insulating resin or housed in an appropriate case, so as to maintain a predetermined positional relationship.

[0082] The rotation sensor 4 is arranged such that the magnetic pole portion 4a formed at the tip of the iron core 401 faces the magnetic pole surface MS of the rotor 3 across a gap, and the side plate portion 404b of the magnetic path component 404 faces a part of the rotor 3 other than the magnetic pole surface MS across a gap, and is attached to the engine by fixing the ear portions 404c, 404c to a rotation sensor mounting portion (not shown) fixed to the engine case.

[0083] In this embodiment, a tip end surface 404b1 of a side plate portion 404b of a magnetic path component 404 faces, via an air gap, an area 304 where no reluctor is formed, which is located near one end in the width direction of the cylindrical surface 302 of the rotor 3. In this way, the side plate portion 404b of the magnetic path component 404 is magnetically coupled to the rotor 3.

[0084] The magnetic path component 404 may be magnetically coupled to a portion of the rotor 3 where no reluctor is formed by facing the tip of its side plate portion 404b to a portion of the bottom wall portion 301b of the rotor 3 near the outer periphery, or may be magnetically coupled to a portion of the rotor 3 where no reluctor is formed by fixing the tip of the side plate portion 404b to another appropriate member that is magnetically coupled to the rotor 3 via a gap.

[0085] In the illustrated signal generator 1, a magnetic path consisting of a loop of permanent magnet 403-iron core 401-air gap-rotor 3-air gap-magnetic path component 404-permanent magnet 403 is formed between the rotor 3 and the rotation sensor 4, and a signal generating magnetic flux that links with the signal coil 402 flows through this magnetic path. As the rotor 3 rotates, the magnetic resistance of the magnetic path changes when each point of action set in the reluctor component 303 passes the position of the magnetic pole portion 4a of the rotation sensor 4. This causes a change in the magnetic flux that links with the signal coil 402, and induces a pulse waveform signal in the signal coil 402.

[0086] In this embodiment, the signal coil 402 constitutes a signal generating unit that generates a signal indicating a level change as a signal containing crank angle information each time the reluctor causes a change in the magnetic flux flowing through the magnetic path during the rotation of the rotor 3.

[0087] In the present invention, the generation position of the signal generated by the signal generating device can be set in any way, but the signal generating device of this embodiment generates a signal for each cylinder of the engine that includes two signals: a signal that provides information that the rotational position of the crankshaft coincides with a rotational position of the crankshaft that can be used as the ignition position when the engine is started during one rotation of the crankshaft, and a signal that provides information that the rotational position of the crankshaft coincides with a reference position, which is the rotational position of the crankshaft when measurement of the ignition position of the engine begins.

[0088] Normally, the ignition position at the start of an engine is set at the top dead center of each cylinder or a position slightly ahead of the top dead center. In this embodiment, the top dead center of each cylinder is set as the ignition position at the start of the engine.

[0089] The signal generating device according to this embodiment can be applied to various types of engines, from single-cylinder engines to multi-cylinder engines, such as single-cylinder four-cycle engines, two-cylinder four-cycle engines, three-cylinder four-cycle engines, and four-cylinder four-cycle engines, by appropriately setting the first set position P1 to the fourth set position P4 on the cylindrical surface 302 of the rotor.

[0090] 6(A) to 6(C) show a development view of a reluctor provided on a rotor when the signal generator of this embodiment is applied to a single-cylinder four-stroke engine, waveform diagrams of signals Vs1 to Vs4 generated by the signal generator, and a stroke diagram showing the strokes performed in the engine cylinders when each signal is generated. In the stroke diagram of Fig. 6(C), INT indicates the intake stroke, COM indicates the compression stroke, EXP indicates the expansion stroke, and EXH indicates the exhaust stroke.

[0091] In this embodiment, the positions of the respective action points of the reluctor and the shape of the reluctor are set so that when the rotational position of the crankshaft coincides with the first set rotational position θ1 to the fourth set rotational position θ4, the first action point to the fourth action point set at the first set position P1 to the fourth set position P4, respectively, pass through the position of the magnetic pole portion 4a of the rotation sensor 4, causing the rotation sensor 4 to output first to fourth signals Vs1 to Vs4.

[0092] In the example shown in Figure 6, when the first point of action, which is set at the tip S1a of the first section S1 that constitutes the portion of the reluctor component 303 near the tip, passes through the position of the magnetic pole portion 4a of the rotation sensor 4 at the first set rotation position θ1 of the crankshaft, the magnetic flux detected by the rotation sensor 4 increases stepwise, causing the rotation sensor 4 to output a first signal Vs1 of a first polarity.

[0093] Furthermore, when the second point of action set at the connection between the rear end S1b of the first section S1 of the first reluctor component 303A and the front end S2a of the second section S2 of the first reluctor component 303A passes through the position of the magnetic pole portion 4a of the rotation sensor 4 at the second set rotation position θ2 of the crankshaft, the magnetic flux detected by the rotation sensor 4 is again increased in a step-like manner, and the rotation sensor 4 again outputs a second signal Vs2 of the first polarity.

[0094] Furthermore, when the third point of action set at the connection between the rear end S2b of the second section S2 of the first reluctor 303A and the front end S3a of the third section S3 of the crankshaft is passed through the position of the magnetic pole portion 4a of the rotation sensor at the third set rotation position θ3 of the crankshaft, the magnetic flux detected by the rotation sensor 4 decreases in a step-like manner, and therefore the rotation sensor 4 outputs a third signal Vs3 having the second polarity at the third set rotation position θ3 of the crankshaft.

[0095] Furthermore, when the fourth point of action set at the rear end S3b of the third section S3 of the first reluctor component passes through the position of the magnetic pole portion 4a at the fourth set rotational position θ4 of the rotor, the magnetic flux detected by the rotation sensor 4 decreases in a step-like manner, and therefore the rotation sensor 4 again outputs a fourth signal Vs4 having the second polarity at the fourth set rotational position θ4 of the crankshaft.

[0096] In this embodiment, the set rotational position θ4 at which the fourth signal Vs4 is generated is set to the top dead center position TDC, which is the rotational position of the crankshaft when the piston reaches top dead center. The set rotational position θ3 at which the third signal Vs3 is generated is set to the reference position Ref, which is the position at which measurement of the ignition position starts. In this embodiment, the reference position Ref is set to a position 90 CA ahead of the top dead center position TDC.

[0097] In this case, if the first ignition at start-up occurs at the top dead center position (TDC), ignition will also occur at the top dead center position when the exhaust stroke (EXH) ends. However, since combustion does not occur during the exhaust stroke, this ignition will not interfere with engine operation.

[0098] In this embodiment, each time the rotation sensor 4 outputs a signal, the currently generated signal and the previously generated signal are detected as a signal pair. If a series of signal pairs detected during one rotation of the crankshaft is referred to as a signal pair group, the signal pair group detected during one rotation of the crankshaft consists of four signal pairs: a first same-polarity signal pair consisting of two signals Vs1 and Vs2 generated consecutively and having a first polarity, a first opposite-polarity signal pair consisting of two signals, signal Vs2 of the first polarity and signal Vs3 of a second polarity, a second same-polarity signal pair consisting of two signals, signal Vs3 and Vs4 of the second polarity, and a second opposite-polarity signal pair consisting of two signals, signal Vs4 of the second polarity and signal Vs1 of the first polarity, generated consecutively.

[0099] Therefore, the rotation sensor 4 outputs the first same-polarity signal pair Vs1, Vs2 only once and the second same-polarity signal pair Vs3, Vs only once per rotor rotation. By generating the first same-polarity signal pair Vs1, Vs2 and the second same-polarity signal pair Vs3, Vs4 once per rotor rotation, either the first same-polarity signal pair or the second same-polarity signal pair Vs3, Vs4 can be generated during one rotation of the crankshaft, regardless of the crankshaft's starting position when starting the engine. Therefore, after starting the engine, the signal generator can reliably determine the signals generated by the signal generator within one rotation of the crankshaft, allowing for rapid acquisition of information on the crankshaft's rotational position and improving engine startability.

[0100] Furthermore, if the first pair of same-polarity signals Vs1, Vs2 and the second pair of same-polarity signals Vs3, Vs4 are each generated once per rotor rotation, there will be two opportunities to determine the signal generation positions during one rotor rotation after the engine starts, thereby improving the accuracy of determining the rotational position of the crankshaft.

[0101] Furthermore, when configured as in this embodiment, two opposite polarity signal pairs, a first opposite polarity signal pair Vs2, Vs3 and a second opposite polarity signal pair Vs4, Vs1, are detected during one rotation of the rotor. However, since the order in which the first polarity signal and the second polarity signal are detected in the first opposite polarity signal pair Vs2, Vs3 is different from the order in which the first polarity signal and the second polarity signal are detected in the second opposite polarity signal pair Vs4, Vs1, the first opposite polarity signal pair Vs2, Vs3 and the second opposite polarity signal pair Vs4, Vs1 can be clearly distinguished and detected.

[0102] Therefore, even if a pair of opposite polarity signals is detected first when the engine is started, the generation position of the later-detected signal among the signals constituting the detected pair of opposite polarity signals can be immediately determined. For example, in FIG. 6, if a signal Vs3 of a second polarity is detected following a signal Vs2 of a first polarity, it can be immediately determined that the later-detected signal Vs3 is a signal generated at the set rotation position θ3 because the second polarity signal was detected following the first polarity signal. Therefore, according to this embodiment, it is possible to quickly and accurately determine each signal output by the rotation sensor.

[0103] 7(A) to 7(D), there are shown a development view of a reluctor provided on a rotor when the signal generating device shown in FIG. 1 is applied to a two-cylinder four-stroke engine, waveform diagrams of signals Vs1 to Vs4 generated by the signal generating device, and a process diagram showing the process performed in the engine cylinder when each signal is generated.

[0104] In this embodiment as well, first setting positions P1 to P4 are set at angular intervals of 90 CA on the outer periphery of the rotating body that constitutes the rotor. Reluctor component 303 is made up of first section S1 extending from setting position P1 to setting position P2, second section S2 extending from setting position P2 to setting position P3, and third section S3 extending from setting position P3 to setting position P4, and first to fourth points of application of the reluctor are set at first setting positions P1 to P4, respectively.

[0105] In this embodiment, the set rotational position θ4 at which the fourth signal Vs4 is generated is set to the top dead center position TDC. The set rotational position θ3 at which the third signal Vs3 is generated is set to the reference position Ref, which is the position at which measurement of the ignition position starts. In this case, the first and second cylinders are ignited simultaneously at the set rotational position θ4 when the engine is started. However, because one of the cylinders is on the compression stroke while the other is on the exhaust stroke, simultaneous ignition in both cylinders does not impede engine operation.

[0106] 8(A)-8(E) show a development view of the reluctor provided on the rotor when a signal generator having the reluctor configuration shown in FIG. 1 is applied to a three-cylinder, four-stroke engine, along with waveform diagrams of first through fourth signals Vs1 through Vs4 generated by the signal generator and a process diagram showing the process performed in the engine cylinders when each signal is generated. In this embodiment, first set positions P1 through P4 are set on the outer periphery of the rotor, and first through fourth points of application of the reluctor are set at the first set positions P1 through P4, respectively. In this embodiment, the angular interval between the first set position P1 and the second set position P2 is set to 60 CA, and the angular interval between the second set position P2 and the third set position P3 and the angular interval between the third set position P3 and the fourth set position P4 are set to 120 CA.

[0107] In this embodiment, the fourth set rotational position θ4 at which the fourth signal Vs4 is generated is set to the top dead center position #1TDC of the first cylinder. The second set rotational position θ2 at which the second signal Vs2 is generated is set to the top dead center position #2TDC of the second cylinder, and the third set rotational position θ3 at which the third signal Vs3 is generated is set to the top dead center position #3TDC of the third cylinder. When the engine is started, ignition occurs in the first, second, and third cylinders at the set rotational positions θ4, θ2, and θ3, respectively.

[0108] 9(A) to 9(F) show an example of the relationship established between the reluctor component 303 provided on the rotor, the signal generated by the signal generating device, and the stroke performed in the cylinders of the engine when the signal generating device according to the present invention having the configuration shown in FIG. 1 is applied to a four-cylinder four-stroke engine.

[0109] In this embodiment, a first set position P1 through a fourth set position P4 are set at 90 CA angular intervals on the outer periphery of the rotating body that constitutes the rotor, and a reluctor component 303 is configured by a first section S1 extending from the first set position P1 to the second set position P2, a second section S2 extending from the second set position P2 to the third set position P3, and a third section S3 extending from the third set position P3 to the fourth set position P4. In this example, a first point of application of the reluctor through a fourth point of application are set at the first set position P1 through the fourth set position P4, respectively. The rotation sensor 4 outputs a first signal Vs1 through a fourth signal Vs4 when the first point of application of the reluctor through the fourth point of application pass the positions of the magnetic pole portions of the rotation sensor 4.

[0110] In this embodiment, the set rotational position θ4 at which the fourth signal Vs4 is generated is set to the top dead center positions #1 / #4TDC of the first and fourth cylinders, the set rotational position θ2 at which the second signal Vs2 is generated is set to the top dead center positions #2 / #3TDC of the second and third cylinders, the set rotational position θ3 at which the third signal Vs3 is generated is set to the reference position #1 / #4Ref of the first and fourth cylinders, and the set rotational position θ1 at which the first signal Vs1 is generated is set to the reference position #2 / #3Ref of the second and third cylinders.

[0111] When starting the engine, if signals Vs3 and Vs4 of the second polarity are detected in succession, the later-generated signal Vs4 is determined to be a signal generated at the set rotational position θ4, and ignition is performed simultaneously in the first and fourth cylinders at the set rotational position θ4. Furthermore, if signals Vs1 and Vs2 of the first polarity are detected in succession, the later-generated signal Vs2 is determined to be a signal generated at the set rotational position θ2, and ignition is performed simultaneously in the second and third cylinders at the set rotational position θ2. In this embodiment, two cylinders are also ignited simultaneously, but because when one of the two simultaneously ignited cylinders is on the compression stroke, the other is on the exhaust stroke, engine operation is not affected.

[0112] Furthermore, when a second polarity signal Vs3 is detected following a first polarity signal Vs2, the later generated second polarity signal Vs3 is determined to be a signal generated at a set rotational position θ3, which is the reference position for the first and fourth cylinders, and when a second polarity signal Vs4 is detected following a first polarity signal Vs1, the later generated signal Vs1 is determined to be a signal generated at a set rotational position θ1, which is the reference position for the second and third cylinders.

[0113] As described above, in the present invention, the first point of action set at the leading end S1a of the first section S1 of the reluctor element 303 and the second point of action set at the connecting portion between the rear end S1b of the first section S1 and the leading end S2a of the second section S2 constitute a first magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor 4 to change in one direction twice consecutively during the rotation of the rotor 3. This first magnetic flux change generating unit causes the magnetic flux detected by the rotation sensor 4 to change in one direction twice consecutively during one rotation of the rotor, and therefore causes the rotation sensor to output a first same-polarity signal pair consisting of two signals Vs1, Vs2 that are generated consecutively and have a first polarity.

[0114] Furthermore, a third point of action set at the connection between rear end S2b of second section S2 and front end S3a of third section S3 of reluctor element 303, and a fourth point of action set at rear end S3b of third section S3, constitute a second magnetic flux change generating unit that causes the magnetic flux detected by rotation sensor 4 to change to the other direction twice consecutively during the rotor's rotation. This second magnetic flux change generating unit causes the magnetic flux detected by rotation sensor 4 to change to the other direction twice consecutively during one rotation of the rotor, and therefore causes rotation sensor 4 to output a second same-polarity signal pair consisting of two second-polarity signals Vs3, Vs4 that are generated consecutively and have the second polarity.

[0115] Since the rotor 3 is provided with one first magnetic flux change generating unit and one second magnetic flux change generating unit, the rotation sensor 4 outputs the first same-polarity signal pair Vs1, Vs2 only once and outputs the second same-polarity signal pair Vs3, Vs4 only once during one rotation of the rotor.

[0116] In this way, by generating the first same-polarity signal pair Vs1, Vs2 having the first polarity and the second same-polarity signal pair Vs3, Vs4 having the second polarity once per rotor rotation, regardless of the position from which the crankshaft starts rotating when the engine start operation is initiated, one of the first same-polarity signal pair or the second same-polarity signal pair can be generated during one rotation of the crankshaft, thereby ensuring that information on the rotational position of the crankshaft can be obtained within one rotation of the crankshaft, thereby improving engine startability.Furthermore, by generating the first same-polarity signal pair Vs1, Vs2 and the second same-polarity signal pair Vs3, Vs4 once per rotor rotation, two opportunities to determine the signal generation positions can be obtained during one rotation of the rotor after the engine has started, thereby improving the accuracy of determining the rotational position of the crankshaft.

[0117] Even if the reluctor provided on the rotor 3 is provided with one first magnetic flux change generator and one second magnetic flux change generator, and is configured to generate the first same-polarity signal pair Vs1, Vs2 and the second same-polarity signal pair Vs3, Vs4 only once per rotor rotation, the first opposite-polarity signal pair Vs2, Vs3 and the second opposite-polarity signal pair Vs4, Vs1 are always generated. In this case, the polarity arrangement of the two signals constituting all signal pairs detected per rotor rotation can be made different, making it possible to easily and reliably determine the generation position of the signals constituting each signal pair. Furthermore, by appropriately setting the lengths of the first to third sections constituting the reluctor element 303, it is possible to accommodate engines ranging from single-cylinder to multi-cylinder.

[0118] However, the present invention is not limited to the configuration shown in FIG. 1, and in addition to the reluctor component having one first magnetic flux change generating unit and one second magnetic flux change generating unit, it does not prevent the provision of a reluctor component that outputs a pair of opposite polarity signals from the rotation sensor.

[0119] Referring to FIG. 10, there is shown a schematic configuration of another embodiment of a signal generating device according to the present invention, in which the reluctor provided on the outer periphery of the rotor is configured by two reluctor components: a first reluctor component 303A having a first magnetic flux change generating unit and a second magnetic flux change generating unit, and a second reluctor component 303B that causes the rotation sensor to output a pair of signals of opposite polarity.

[0120] In this embodiment, the engine to which the signal generating device 1 is applied is a three-cylinder engine, and the angle interval between the top dead center positions #1TDC to #3TDC of the first to third cylinders is 120 degrees.

[0121] In this embodiment, the entire rotor 301 is formed from a ferromagnetic material such as iron, and a first reluctor component 303A and a second reluctor component 303B extending circumferentially of the rotor 301 are provided in a region near the center of the width of a cylindrical surface 302 formed on the outer periphery of the rotor 301, spaced apart from each other in the circumferential direction of the rotor 301 and with their respective longitudinal directions aligned with the circumferential direction of the rotor 301, and these reluctor components form a reluctor.

[0122] More specifically, the first reluctor component 303A includes a first section S1 extending from a first set position P1 to a second set position P2 along the circumferential direction of the cylindrical surface 302 with its leading end S1a facing forward in the rotation direction R of the rotor 3 and its rear end facing rearward in the rotation direction R of the rotor 3, a second section S2 extending from a second set position P2 to a third set position P3 along the circumferential direction of the cylindrical surface 302 with its leading end S2a connected to the rear end of the first section S1 and its rear end facing rearward in the rotation direction R of the rotor 3, and a leading end S3a connected to the rear end of the second section S2 and its rear end S3b facing rearward in the rotation direction R of the rotor 3. Cylindrical surface and a third section S3 extending from a third setting position P3 to a fourth setting position P4 along the circumferential direction of the first reluctor component 303A. The first reluctor component 303A has the same structure as the reluctor component 303 used in the embodiment shown in FIG.

[0123] The second reluctor component 303B consists of a fourth section S4 extending from a fifth set position P5 to a sixth set position P6 with its leading end S4a facing forward in the rotation direction R of the rotor 3 and its trailing end S4b facing backward in the rotation direction R of the rotor 3.

[0124] Tip S4a of fourth section S4 constituting second reluctor component 303B rises perpendicularly from cylindrical surface 302 of the rotor at fifth set position P5 set on cylindrical surface 302 of the rotor, thereby setting a fifth point of application of the reluctor at fifth set position P5. When this fifth point of application passes the position of the magnetic pole portion of rotation sensor 4 in the process of rotor 3 rotation, the distance between the magnetic pole portion of rotation sensor 4 and the magnetic pole surface of the rotor changes stepwise in the decreasing direction. At this time, the magnetic flux detected by rotation sensor 4 changes in one direction, so rotation sensor 4 outputs a signal of a first polarity.

[0125] Furthermore, rear end S4b of fourth section S4 descends perpendicularly toward rotor cylindrical surface 302 at sixth set position P6, which is set on rotor cylindrical surface 302, and as a result a sixth point of action of the reluctor is set at sixth set position P6. As the rotor rotates and passes the position of the magnetic pole portion of rotation sensor 4, this sixth point of action changes in a stepwise manner, increasing the distance between the magnetic pole portion of rotation sensor 4 and the rotor magnetic pole surface, thereby decreasing the magnetic flux detected by rotation sensor 4 and causing rotation sensor 4 to output a signal of the second polarity.

[0126] 10, the angular intervals between the first set position P1 and the second set position P2, the angular intervals between the third set position P3 and the fourth set position P4, and the angular intervals between the fifth set position P5 and the sixth set position P6 are set to 40 CA, while the angular intervals between the second set position P2 and the third set position P3, the angular intervals between the fourth set position P4 and the fifth set position P5, and the angular intervals between the sixth set position P6 and the first set position P1 are set to 80 CA.

[0127] Figures 11(A) and 11(B) show an exploded view of the reluctor of the signal generator shown in Figure 10 and the waveforms of signals Vs1 to Vs6 generated by the signal generator. In Figure 11, #1TDC to #3TDC indicate the top dead center positions of cylinders 1 to 3 of the engine, respectively. Also, #1Ref to #3Ref indicate the reference positions of cylinders 1 to 3, which are set 40 CA before the top dead center positions #1TDC to #3TDC of cylinders 1 to 3, respectively.

[0128] In this embodiment, the first set rotational position θ1 at which the first signal Vs1 is generated corresponds to the reference position #1Ref for the first cylinder, and the second set rotational position θ2 at which the second signal Vs2 is generated corresponds to the top dead center position #1TDC for the first cylinder. The third set rotational position θ3 at which the third signal Vs3 is generated corresponds to the reference position #2Ref for the second cylinder, and the fourth set rotational position θ4 at which the fourth signal Vs4 is generated corresponds to the top dead center position #2TDC for the second cylinder. The fifth set rotational position θ5 at which the fifth signal Vs5 is generated corresponds to the reference position #3Ref for the third cylinder, and the sixth set rotational position θ6 at which the sixth signal Vs6 is generated corresponds to the top dead center position #3TDC for the third cylinder.

[0129] In this embodiment, when the first point of application of the reluctor set at the first set position P1 passes the position of the magnetic pole portion 4a of the rotation sensor at the first set rotation position θ1, the rotation sensor outputs a first signal Vs1 of positive polarity, when the second point of application of the reluctor set at the second set position P2 passes the position of the magnetic pole portion of the rotation sensor at the second set rotation position θ2, the rotation sensor outputs a second signal Vs2 of positive polarity, when the third point of application of the reluctor set at the third set position P3 passes the position of the magnetic pole portion of the rotation sensor at the third set rotation position θ3, the rotation sensor outputs a third signal Vs3 of negative polarity, and when the fourth point of application of the reluctor set at the fourth set position P4 passes the position of the magnetic pole portion of the rotation sensor at the fourth set rotation position θ4, the rotation sensor outputs a fourth signal Vs4 of negative polarity. Furthermore, when the fifth point of action of the reluctor set at the fifth set position P5 passes the position of the magnetic pole portion of the rotation sensor at the fifth set rotation position θ5, the rotation sensor outputs a fifth signal Vs5 of positive polarity, and when the sixth point of action of the reluctor set at the sixth set position P6 passes the position of the magnetic pole portion of the rotation sensor at the sixth set rotation position θ6, the rotation sensor outputs a sixth signal Vs6 of negative polarity.

[0130] In this embodiment, it is possible to determine at which rotational position each signal was generated based on the polarity of the signals that make up the signal string output by the rotation sensor. For example, by expressing the first polarity as "1" and the second polarity as "0," and checking the combination of polarities of the signals that make up the signal string consisting of two successively generated signals, it is possible to determine at which rotational position each signal was generated.

[0131] For example, when the signal sequence "11" is detected, the signal generated later of the two signals constituting this signal sequence can be determined to be signal Vs2 generated at the set rotational position θ2, and this signal can be determined to be the signal generated at the top dead center position #1TDC of the first cylinder.

[0132] Furthermore, when the signal sequence "10" is detected following the signal sequence "11," the signal generated later of the two signals constituting this signal sequence can be determined to be the signal generated at the set rotational position θ3, and this signal can be determined to be the signal Vs3 generated at the reference position #2Ref of the second cylinder.

[0133] Furthermore, when the signal sequence "00" is detected, it can be determined that the later of the two signals that make up this signal sequence is the signal that occurred at the set rotational position θ4, and that this signal is the signal Vs4 that occurred at the top dead center position #2TDC of the second cylinder.

[0134] Furthermore, when a signal sequence "01" is detected following a signal sequence "00," it can be determined that the later of the two signals constituting this signal sequence is the signal generated at the set rotational position θ5, and that this signal is the signal Vs5 generated at the reference position #3Ref of the third cylinder.

[0135] When a signal sequence "10" is detected following a signal sequence "01," it can be determined that the later of the two signals constituting this signal sequence is the signal generated at the set rotational position θ6, and that this signal is the signal Vs6 generated at the top dead center position #3TDC of the third cylinder.

[0136] When a signal sequence "01" is detected following a signal sequence "10," it can be determined that the later of the two signals constituting this signal sequence is the signal generated at the set rotational position θ1, and that this signal is the signal generated at the reference position #1Ref of the first cylinder.

[0137] Furthermore, it is also possible to determine at which rotational position the signal output by the rotation sensor was generated, based on the polarities of the three signals output in succession by the rotation sensor. As is clear from Figure 3, the signal string consisting of three signals generated in succession by the signal generator of this embodiment changes as follows during one rotation of the crankshaft: "001", "010", "101", "011", "110", and "100". Since there are no signal strings with the same signal polarity arrangement among these signal strings, by using the signal string consisting of three signals generated in succession by the signal generator to perform signal determination, it is possible to easily determine which set position the last signal of the three signals constituting each signal string corresponds to.

[0138] For example, in the example shown in Figure 11, when the signal sequence "101" is first detected after the engine start operation is initiated, it can be determined that the last signal of the three signals constituting this signal sequence occurred at the reference position #1Ref of the first cylinder. Similarly, when the signal sequence "011" is next detected, it can be determined that the last signal of this signal sequence occurred at the top dead center position #1TDC of the first cylinder. In this manner, it is possible to sequentially determine the occurrence position of the last signal of each of the three signals constituting a series of signals.

[0139] In the above embodiment, the ignition position at engine start is set to the top dead center position of each cylinder, and the later of the two signals constituting each signal pair is generated at the top dead center position of each cylinder, but the ignition position of each cylinder at engine start is not limited to the top dead center position of each cylinder. For example, the ignition position at engine start may be set to a rotational position slightly ahead of the top dead center position of each cylinder, and the later of each pair of signals may be generated at the set ignition position at engine start.

[0140] 12 shows another embodiment of a signal generating device according to the present invention. In this embodiment, first to sixth set positions P1 to P6 are set on the cylindrical surface 302 of the rotor 3. In this embodiment, the angular interval between the first set position P1 and the second set position P2, the angular interval between the second set position P2 and the third set position P3, the angular interval between the third set position P3 and the fourth set position P4, the angular interval between the fourth set position P4 and the fifth set position P5, and the angular interval between the fifth set position P5 and the sixth set position P6 are all set to 60 CA.

[0141] In this embodiment as well, a reluctor is formed by first reluctor component 303A and second reluctor component 303B provided on cylindrical surface 302 of rotor 3. First reluctor component 303A is made up of a first section S1 extending from first setting position P1 to second setting position P2, a second section S2 extending from second setting position P2 to third setting position P3, and a third section S3 extending from third setting position P3 to fourth setting position P4.

[0142] The first section S1 to the third section S3 constituting the first reluctor component 303A are configured similarly to the first section S1 to the third section S3 constituting the first reluctor component 303A of the rotor 3 used in the embodiment shown in Fig. 10, except that each section has a pole arc angle of 60 CA. The second reluctor component 303B is made up of an arc-shaped fourth section S4 extending circumferentially of the rotor 3 from a fifth setting position P5 to a sixth setting position P6.

[0143] In the signal generating device shown in FIG. 12, the first to sixth action points of the reluctor are set at the first to sixth setting positions P1 to P6, respectively, and when these action points pass the position of the magnetic pole portion 4a of the rotation sensor, the signal coil 402 constituting the signal generating unit outputs the first to sixth signals Vs1 to Vs6 in pulse waveforms.

[0144] Figures 13(A) and 13(B) show an exploded view of the reluctor of the signal generator shown in Figure 12 and the waveforms of signals Vs1 to Vs6 generated by the signal generator. Figures 13(C) to 13(E) show the strokes performed by the first cylinder #1, the second cylinder #2, and the third cylinder #3 of the engine, respectively. In Figures 13(C) to 13(E), INT and COM indicate the intake stroke and compression stroke, respectively, and EXP and EXH indicate the expansion stroke and exhaust stroke, respectively.

[0145] 13, #1TDC to #3TDC indicate the top dead center positions of the first to third cylinders of the engine, respectively. Also, #1Ref to #3Ref indicate the reference positions of the first to third cylinders, which are set at positions 60 CA before the top dead center positions #1TDC to #3TDC of the first to third cylinders, respectively. In this embodiment, the rotation sensor 4 outputs a pulse waveform signal every time the rotor 3 rotates 60 CA.

[0146] In this example, the first set rotational position θ1 is the reference position #2Ref for the second cylinder, the second set rotational position θ2 is the top dead center position #2TDC for the second cylinder, the third set rotational position θ3 is the reference position #3Ref for the third cylinder, and the fourth set rotational position θ4 is the top dead center position #3TDC for the third cylinder, the fifth set rotational position θ5 is the reference position #1Ref for the first cylinder, and the sixth set rotational position θ6 is the top dead center position #1TDC for the first cylinder.

[0147] In the illustrated example, when the rotational position of the crankshaft coincides with the first set rotational position θ1 at the reference position #2Ref for the second cylinder, the first point of application of the reluctor, which is set at the first set position P1 on the outer periphery of the rotor, passes through the position of the magnetic pole portion 4a of the rotation sensor, causing the rotation sensor to output a first signal Vs1 of positive polarity. Also, when the rotational position of the crankshaft coincides with the second set rotational position θ2 at the top dead center position #2TDC for the second cylinder, the second point of application of the reluctor, which is set at the second set position P2 on the outer periphery of the rotor, passes through the position of the magnetic pole portion 4a of the rotation sensor, causing the rotation sensor to output a second signal Vs2 of positive polarity.

[0148] Furthermore, when the rotational position of the crankshaft coincides with the third set rotational position θ3 at the reference position #3Ref of the third cylinder, the third point of action of the reluctor, which is set at the third set position P3 on the outer periphery of the rotor, passes through the position of the magnetic pole portion 4a, causing the rotation sensor to output a third signal Vs3 of negative polarity.When the rotational position of the crankshaft coincides with the fourth set rotational position θ4 at the top dead center position #3TDC of the third cylinder, the fourth point of action of the reluctor passes through the position of the magnetic pole portion 4a, causing the rotation sensor to output a fourth signal Vs4 of negative polarity.

[0149] In this embodiment, too, it is possible to determine at which rotational position each signal was generated based on the polarity of the signals constituting a signal train consisting of two signals successively output by the rotation sensor. Similarly, it is also possible to determine the cylinder of each signal generated by the signal generator based on the combination of polarities of the signals constituting a signal train consisting of three signals successively output by the signal generator: "001", "010", "101", "011", "110", and "100".

[0150] In the example shown in Fig. 13, the signal generator shown in Fig. 12 in which the reluctor is configured by first reluctor element 303A and second reluctor element 303B is applied to a three-cylinder engine, but the engine to which the signal generator shown in Fig. 12 can be applied is not limited to a three-cylinder engine. For example, the signal generator shown in Fig. 12 can be applied to a six-cylinder engine.

[0151] Fig. 14 shows the relationship between the reluctor, a series of signals output by the rotation sensor, and the strokes performed by the six cylinders of the engine in an embodiment in which the signal generating device shown in Fig. 12 is applied to a six-cylinder engine. Fig. 14(A) is a development view of the reluctor used in this embodiment, Fig. 14(B) is a waveform diagram showing the waveforms of signals obtained when the same reluctor is used, and Figs. 14(C) to (H) are stroke diagrams showing the strokes performed by the six cylinders of the six-cylinder engine when each signal shown in Fig. 14(B) is generated.

[0152] 14, the rotation sensor 4 outputs the first signal Vs1 through the sixth signal Vs6 at the first set rotational position θ1 through the sixth set rotational position θ6 of the crankshaft, respectively. In the example shown in FIG. 14, the first set rotational position θ1 of the rotor at which the first signal Vs1 is generated is the reference position #2 / #5Ref of the second and fifth cylinders of a six-cylinder engine, and the second set rotational position θ2 of the crankshaft at which the second signal Vs2 is generated is the top dead center position #2 / #5TDC of the second and fifth cylinders. The third set rotational position θ3 of the crankshaft at which the third signal Vs3 is generated is the reference position #3 / #4Ref of the third and fourth cylinders, and the fourth set rotational position θ4 of the crankshaft at which the fourth signal Vs4 is generated is the top dead center position #3 / #4TDC of the third and fourth cylinders. The fifth set rotational position θ5 of the crankshaft at which the fifth signal Vs5 is generated is the reference position #1 / #6Ref of the first and sixth cylinders, and the set rotational position θ6 of the crankshaft at which the sixth signal Vs6 is generated is the top dead center position #1 / #6TDC of the first and sixth cylinders.

[0153] In the above embodiment, the first reluctor component 303A is configured from the first section S1 to the third section S3, and the second reluctor component 303B is configured from the fourth section S4, but the present invention is not limited to configuring the reluctor components in this manner. For example, as shown in Figure 15, each of the first reluctor component 303A and the second reluctor component 303B may be configured from two sections.

[0154] 15, the angles between the first through sixth setting positions P1 through P6 are all set to 60 CA. A first reluctor component 303A is formed by a first section S1 extending from the first setting position P1 to the second setting position P2 and a second section S2 extending from the second setting position P2 to the third setting position P3, and the first through third points of application of the reluctor are set at the first setting position P1 to the third setting position P3, respectively. A second reluctor component 303B is formed by a third section S3 extending from the fourth setting position P4 to the fifth setting position P5 and a fourth section S4 extending from the fifth setting position P5 to the sixth setting position P6, and the fourth through sixth points of application of the reluctor are set at the fourth setting position P4 to the sixth setting position P6, respectively.

[0155] 15 , as the rotor 3 rotates forward in the direction of arrow R, the magnetic flux detected by the rotation sensor changes direction when a first set position P1 passes the position of the magnetic pole of the rotation sensor, causing the rotation sensor to output a first signal Vs1 with a first polarity. Then, when a second set position P2 passes the position of the magnetic pole of the rotation sensor, the magnetic flux detected by the rotation sensor changes direction again, causing the rotation sensor to output a second signal Vs2 with the same polarity as the first signal Vs1. Next, when a third set position P3 passes the position of the magnetic pole of the rotation sensor, the magnetic flux detected by the rotation sensor changes direction again, causing the rotation sensor to output a third signal Vs3 with a second polarity. Then, when a fourth set position P4 passes the position of the magnetic pole of the rotation sensor, the magnetic flux detected by the rotation sensor changes direction again, causing the rotation sensor to output a fourth signal Vs4 with the second polarity.

[0156] 15, the first set position P1 and the second set position P2 are set so that the first set rotational position θ1, which is the rotational position of the crankshaft when the first set position P1 passes the position of the magnetic pole portion of the rotation sensor, coincides with the bottom dead center position #2BDC of the second cylinder, and the second set rotational position θ2, which is the rotational position of the crankshaft when the second set position P2 passes the position of the magnetic pole portion of the rotation sensor, coincides with the top dead center position #1TDC of the first cylinder. Also, the third set position P3 is set so that the third set rotational position θ3, which is the rotational position of the crankshaft when the third set position P3 passes the position of the magnetic pole portion of the rotation sensor, coincides with the bottom dead center position #3BDC of the third cylinder.

[0157] 15, the fourth set position P4 and the fifth set position P5 are set so that the fourth set rotational position θ4, which is the rotational position of the crankshaft when the fourth set position P4 passes the position of the magnetic pole portion of the rotation sensor, coincides with the top dead center position #2TDC of the second cylinder, and the fifth set rotational position θ5, which is the rotational position of the crankshaft when the fifth set position P5 passes the position of the magnetic pole portion of the rotation sensor, coincides with the bottom dead center position #1BDC of the first cylinder. Also, the sixth set position P6 is set so that the sixth set rotational position θ6, which is the rotational position of the crankshaft when the sixth set position P6 passes the position of the magnetic pole portion of the rotation sensor, coincides with the top dead center position #3TDC of the third cylinder.

[0158] 15, if the positive polarity of the signal is represented by "1" and the negative polarity is represented by "0," a signal string consisting of two signals successively generated by the signal coil changes as follows during one rotation of the crankshaft: "11," "10," "01," "10," "00," "01." Using these signal strings, it is possible to determine which set position the signal generated last among the signals constituting each signal corresponds to.

[0159] 15, a signal train consisting of three signals successively generated by the signal coil changes during one rotation of the crankshaft, such as "110," "101," "010," "100," "001," and "011." By detecting these signal trains, it is possible to determine which set position the last-generated signal of the three signals constituting each signal train corresponds to.

[0160] The rotation sensor used in the signal generating device of the present invention is configured to include a sensor magnetic pole portion that faces the magnetic pole face of the reluctor via an air gap, a magnet that causes magnetic flux to flow in a magnetic path that includes the sensor magnetic pole portion and the reluctor, and a signal generating portion that generates a signal indicating a level change as a signal containing crank angle information each time the reluctor causes a change in the magnetic flux flowing in the magnetic path during the rotation of the rotor.

[0161] The rotation sensor used in the above embodiment comprises a rotation sensor core 401 having a sensor magnetic pole portion 4a at its tip and constituting part of the magnetic path, a magnet 403 that passes a signal-generating magnetic flux through the core, and a signal coil 402 wound around the rotation sensor core 401, with the signal coil constituting the signal generating section, but the signal generating section used in the present invention is not limited to a signal coil.

[0162] For example, the signal generating unit may be constituted by a magnetic sensor that detects the signal-generating magnetic flux flowing through the magnetic path and outputs a voltage signal at a level corresponding to the amount of detected magnetic flux, or the signal generating unit may be constituted by a magnetic sensor that detects the signal-generating magnetic flux and outputs a voltage signal at a level corresponding to the amount of detected magnetic flux, and a signal converting unit that converts changes in the level of the voltage signal output by the magnetic sensor into a pulse signal.

[0163] When the signal generating unit is configured with a magnetic sensor that detects signal generating magnetic flux and outputs a voltage signal at a level corresponding to the amount of detected magnetic flux, the voltage signal Vh generated by the signal generating unit changes, for example, as shown in Fig. 16(A). The portions of this voltage signal that indicate each level change can be used as a signal containing crank angle information.

[0164] Furthermore, when the signal generating unit is configured with a magnetic sensor that detects signal generating magnetic flux and outputs a voltage signal with a level corresponding to the amount of detected magnetic flux, and a signal converting unit that converts the change in level of the voltage signal output by the magnetic sensor into a pulse signal, the waveform of the signal output by the signal generating unit is, for example, as shown in Fig. 16(B). A Hall element can be used as the magnetic sensor, and the signal converting unit that converts the change in level of the voltage signal output by the magnetic sensor into a pulse signal can be configured with, for example, a differential circuit.

[0165] Next, taking the embodiment shown in Figure 9 as an example, an example of a discrimination processing algorithm that the microprocessor executes when determining at which rotational position of the crankshaft each signal generated by the signal generating device was generated will be described using the flowcharts shown in Figures 17 to 19.

[0166] 17 to 19, the pulse signal generated when the tip of each section of the reluctor passes the position of the magnetic pole part of the rotation sensor is called an "enter pulse," meaning that it is a pulse signal generated when the reluctor enters the position of the magnetic pole part 4a. Also, the pulse signal generated when the rear end of each section of the reluctor passes the position of the magnetic pole part of the rotation sensor is called an "exit pulse," meaning that it is a pulse signal generated when the reluctor exits the position of the magnetic pole part 4a of the rotation sensor. Also, the interrupt processing executed when an "enter pulse" occurs is called an "enter interrupt," and the interrupt processing executed when an "exit pulse" occurs is called an "exit interrupt."

[0167] Fig. 17 shows an algorithm for crank angle interrupt processing that is executed every time the signal generating device generates a signal (a pulse signal in this embodiment) that includes crankshaft rotational position information (crank angle information). Fig. 18 shows an algorithm for initial processing that is executed in the crank angle interrupt processing of Fig. 17, and Fig. 19 shows an algorithm for main determination processing that is executed in the crank angle interrupt processing of Fig. 17.

[0168] In the flowchart of Figure 17, First_f is a first interrupt detection flag that takes the value "0" if the current interrupt is the first interrupt and takes the value "1" if it is not the first interrupt. Here, the first interrupt means an interrupt that is executed when the rotation sensor generates a pulse for the first time. Judge_f is a signal generation position discrimination judgment flag that takes the value "0" if the determination of the signal generation position has not been completed and is set to "1" when the determination has been completed.

[0169] When the crank angle interruption process of Fig. 17 is started, first, in step S001, it is determined whether the first interruption detection flag First_f is 0. As a result, if First_f is 0 and it is determined that the current interruption is the first interruption, the process proceeds to step S002, where the first interruption process shown in Fig. 18 is executed, and then the crank angle interruption process is terminated.

[0170] If it is determined in step S001 that the first interrupt detection flag First_f is not 0 and that the interrupt to the crank angle interrupt process in Fig. 17 is not the first interrupt, the process proceeds to step S003, where it is determined whether the signal generation position discrimination determination flag Judge_f is 0. If it is determined that Judge_f is 0, that is, if it is determined that the signal generation position has not yet been determined, the process proceeds to step S004, where the main determination process shown in Fig. 19 is executed, and then the crank angle interrupt process in Fig. 17 is terminated.

[0171] In step S003, when it is determined that Judge_f is not 0, that is, when it is determined that the signal generation position determination process has been completed, the process proceeds to step S005, where an instruction is issued to execute the normal operation process after the determination of the signal generation position has been completed, and then this process is terminated.

[0172] Next, the initial process shown in Fig. 18, which is executed in step S002 of the crank angle interrupt process shown in Fig. 17, will be described. In Fig. 18, Prev_ind is an indicator indicating whether the previously generated pulse was an incoming pulse or a missing pulse. This indicator is set to 0 during initialization, which is performed when the microprocessor is started.

[0173] When the initial processing of FIG. 18 is started, in step S101, it is determined whether the current interrupt is an "incoming interrupt." That is, it is determined whether the pulse that caused the current interrupt processing to be executed is the incoming pulse Vs1 generated at the first set rotation position θ1 shown in FIG. 9. As a result, if it is determined that the current interrupt is an incoming interrupt, the process proceeds to step S102, where Prev_ind is set to 1. This stores the fact that the pulse generated this time was an incoming pulse. Next, the process proceeds to step S103, where the first interrupt detection flag First_f is set to 1, and the initial determination processing ends.

[0174] If it is determined in step S101 that the current interrupt is not an incoming interrupt, the process proceeds to step S104, where Prev_ind is set to 2 to indicate that the currently generated pulse was a missing pulse. Next, the process proceeds to step S103, where the first interrupt detection flag First_f is set to 1, and the first determination process is terminated.

[0175] Next, with reference to FIG. 19, the main determination process executed in step S004 of the crank angle interrupt process shown in FIG. 17 will be described. In the flowchart of FIG. 19, Position_No is a position number indicating the position at which the currently generated pulse signal was generated. Position_No is assigned a value of 1, 2, 3, or 4 depending on the position at which the pulse signal was generated. In the main determination process of FIG. 19, if it is determined that the currently generated pulse signal was generated at the first set rotational position θ1 of the crankshaft, Position_No is set to "1." If it is determined that the currently generated pulse signal was generated at the second set rotational position θ2 of the crankshaft, Position_No is set to "2." If it is determined that the currently generated pulse signal was generated at the third set rotational position θ3 of the crankshaft, Position_No is set to "3." If it is determined that the currently generated pulse signal was generated at the fourth set rotational position θ4 of the crankshaft, Position_No is set to "4."

[0176] When the main determination process of FIG. 19 starts, first, in step S201, it is determined whether Prev_ind is 1. As a result, if it is determined that Prev_ind is not 1, that is, if it is determined that the previously generated pulse is not an incoming pulse, the process proceeds to step S202, where it is determined whether the current interrupt is an incoming interrupt, that is, whether the current interrupt process is an interrupt process executed due to the generation of an incoming pulse. As a result, if it is determined that the current interrupt is an incoming interrupt, the process proceeds to step S203, where Position_No is set to "1," and the determination result that the currently generated pulse signal is the first signal Vs1 generated at the first set rotation position θ1 is left. Next, the process proceeds to step S204, where Judge_f is set to 1, thereby storing the completion of the determination of the generation position of the currently generated pulse signal, and then the main determination process of FIG. 19 ends.

[0177] 19, if it is determined that Prev_ind is 1, i.e., if it is determined that the previously generated pulse is an incoming pulse, the process proceeds to step S205, where it is determined whether the current interrupt is an incoming interrupt. If it is determined that the current interrupt is an incoming interrupt, the process proceeds to step S206, where Position_No is set to "2," and the determination result that the currently generated pulse signal is the second signal Vs2 generated at the second set rotation position θ2 is left. Next, the process proceeds to step S204, where Judge_f is set to 1, and the completion of determination of the generation position of the currently generated pulse signal is stored, and then the main determination process of FIG. 19 is terminated.

[0178] 19, if it is determined in step S201 that Prev_ind is 1, and if it is determined in step S205 that the current interrupt is not an interrupt, the process proceeds to step S207, where Position_No is set to "3," and the determination result that the currently generated pulse signal is the third signal Vs3 generated at the third set rotation position θ3 is left. Next, the process proceeds to step S204, where Judge_f is set to 1, and the completion of determination of the generation position of the currently generated pulse signal is stored, and then the main determination process in FIG. 19 is terminated.

[0179] 19, if it is determined in step S201 that Prev_ind is not 1, and if it is determined in step S202 that the current interrupt has occurred and is not an interrupt, the process proceeds to step S208, where Position_No is set to "4," and the determination result that the currently generated pulse signal is the fourth signal Vs4 generated at the fourth set rotation position θ4 is left. Next, the process proceeds to step S204, where Judge_f is set to 1, and the completion of determination of the generation position of the currently generated pulse signal is stored, and then the main determination process in FIG. 19 is terminated.

[0180] 17 to 19 are repeated each time the rotation sensor generates a pulse signal while the engine is running, and each time the rotation sensor outputs a pulse signal while the engine is running, a determination is made as to which of the set rotation positions θ1 to θ4 the pulse signal was generated at. The engine control device obtains information about the rotation position of the crankshaft from the determination result and controls the ignition position, etc.

[0181] In the above embodiment, the cylindrical surface of the rotor on which the reluctor is provided is provided on the outer periphery of the rotor, and the rotation sensor is located on the outside of the rotor, but the present invention is not limited to this configuration, and can also be applied to a configuration in which the cylindrical surface on which the reluctor is provided is provided on the inner periphery of the rotor, and the rotation sensor is located inside the rotor.

[0182] In the above embodiment, the reluctor is a protrusion formed on the cylindrical surface of the rotor, but the reluctor may be a recess or groove formed on the cylindrical surface of the rotor. When the reluctor is formed as a recess or groove, the recess or groove may be filled with a non-magnetic material.

[0183] 12, when the reluctor is composed of a first reluctor component 303A and a second reluctor component 303B, regions without protrusions are provided on the outer periphery of the rotor located between the leading end of the first reluctor component 303A and the rear end of the second reluctor component 303B and between the leading end of the second reluctor component 303B and the rear end of the first reluctor component 303A, respectively. However, a configuration in which protrusions are provided in the entire region along the circumferential direction of the rotor may also be adopted. For example, in FIG. 12, the leading end of section S1 and the rear end of section S4, and the leading end of section S4 and the rear end of section S3 may be connected by arc-shaped protrusions that extend continuously between sections S1 and S4 and between sections S3 and S4, with a constant width smaller than the widths of sections S1 and S3.

[0184] Similarly, in the embodiment shown in Figure 1, the leading end S1a of the first section S1 and the rear end of the third section S3 may be connected by an arc-shaped protrusion that extends continuously between the leading end S1a of the first section S1 and the rear end of the third section S3, with a constant width dimension that is smaller than the width dimension of the first section S1 and the width dimension of the third section S3.

[0185] In the above embodiment, as shown in FIG. 2, the first and second magnetic flux change generators are configured by gradually varying the width dimensions of the sections constituting the reluctor components at both the front and rear ends of the reluctor. Alternatively, as shown in FIG. 4, the first and second magnetic flux change generators are configured by varying the heights of the sections constituting the reluctor components at both the front and rear ends of the reluctor. However, the present invention is not limited to this configuration. For example, the first magnetic flux change generator may be configured by varying the heights of sections S1 and S2 constituting the reluctor components at the front end of the reluctor component, and the second magnetic flux change generator may be configured by varying the width dimensions of sections S2 and S3 constituting the reluctor components at the rear end of the reluctor component. Alternatively, the first and second magnetic flux change generators may be configured by gradually varying both the width and height of the sections constituting the reluctor components. [Explanation of symbols]

[0186] 1. Signal Generator 2 crankshaft 3 rotors 301 Rotating Body 301a Peripheral wall part 301b Bottom wall 301c boss part 302 Cylindrical surface of rotor 303A First Reluctor Component 303B Second Reluctor Component 4 Rotation Sensor 4a Magnetic pole part of rotation sensor 401 Iron Core 402 Signal coil (signal generator) 403 Magnet 404 Magnetic path components P1 The first set position set on the cylindrical surface of the rotor P2: The second set position on the rotor's cylindrical surface P3: The third set position on the rotor's cylindrical surface P4: The fourth set position on the rotor's cylindrical surface P5: The fifth set position on the rotor's cylindrical surface P6: The sixth set position on the rotor's cylindrical surface θ1 First set rotation position of the crankshaft θ2 Second set rotation position of the crankshaft θ3 Third set rotation position of crankshaft θ4: The fourth set rotation position of the crankshaft θ5: The fifth set rotation position of the crankshaft θ6: The sixth set rotation position of the crankshaft S1 First Section S2 Second Section S3 Third Section S4 Fourth Section S5 Fifth Section S6 Sixth Section MS magnetic pole face Vs1 First signal Vs2 Second signal Vs3 Third signal Vs4 Fourth Signal Vs5 Fifth Signal Vs6 6th signal

Claims

1. A signal generating device for an engine, comprising: a rotation sensor fixed to an engine case, configured to output a signal each time a change in magnetic flux is detected; and a rotor provided to rotate with a crankshaft of the engine, the rotor having a reluctor that causes a change in magnetic flux detected by the rotation sensor in one direction or another each time the rotational position of the crankshaft matches a set rotational position, wherein the rotation sensor outputs a signal of a first polarity when the reluctor changes the magnetic flux in one direction, and the rotation sensor outputs a signal of a second polarity when the reluctor changes the magnetic flux in the other direction, the reluctor is configured to have one first magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change in one direction twice in succession while the rotor is rotating, and one second magnetic flux change generating unit that causes the magnetic flux detected by the rotation sensor to change in the other direction twice in succession while the rotor is rotating, When two signals successively output by the rotation sensor are captured as a signal pair, a group of signal pairs output by the rotation sensor during one rotation of the rotor includes one first signal pair of the same polarity consisting of two signals of the first polarity, and one second signal pair of the same polarity consisting of two signals of the second polarity.

2. 2. The signal generating device for an engine according to claim 1, wherein the reluctor is provided so that a group of signal pairs output by the rotation sensor during one rotation of the rotor consists of four signal pairs: a first same-polarity signal pair consisting of two signals of the first polarity, a first opposite-polarity signal pair consisting of two signals of the first polarity and the second polarity that are generated successively, a second same-polarity signal pair consisting of two signals of the second polarity, and a second opposite-polarity signal pair consisting of two signals of the second polarity and the first polarity that are generated successively.

3. 2. The signal generating device for an engine according to claim 1, wherein the reluctor is provided so that a group of signal pairs output by the rotation sensor during one rotation of the rotor consists of six signal pairs: a first same-polarity signal pair consisting of two signals of the first polarity, a first opposite-polarity signal pair consisting of two signals of the first polarity and the second polarity that are generated successively, a second same-polarity signal pair consisting of two signals of the second polarity, a second opposite-polarity signal pair consisting of two signals of the second polarity and the first polarity that are generated successively, a third opposite-polarity signal pair consisting of two signals of the first polarity and the second polarity that are generated successively, and a fourth opposite-polarity signal pair consisting of the second polarity signal and the first polarity signal that are generated successively.

4. the rotor has a cylindrical surface that is disposed in a state where the rotor and the crankshaft share a central axis when the rotor is attached to the engine, and the reluctor is provided on this cylindrical surface; The rotation sensor comprises: a magnetic pole portion that faces an area of ​​the cylindrical surface of the rotor where a reluctor is provided, with a gap therebetween; a magnet that causes a signal-generating magnetic flux to flow in a magnetic path formed to include the magnetic pole portion and the area of ​​the rotor where the reluctor is provided; and a signal generating portion that generates a signal indicating a level change every time the reluctor causes a change in the signal-generating magnetic flux during the process of rotation of the rotor; the reluctor comprises a protrusion or recess as a reluctor component, the protrusion or recess having: a first section extending in the circumferential direction of the cylindrical surface with a constant width dimension, with a leading end facing forward in the rotation direction of the rotor and a trailing end facing backward in the rotation direction of the rotor; a second section extending in the circumferential direction of the cylindrical surface with a constant width dimension, with a leading end connected to the trailing end of the first section and a trailing end facing backward in the rotation direction of the rotor; and a third section extending in the circumferential direction of the cylindrical surface with a constant width dimension, with a leading end connected to the trailing end of the second section and a trailing end facing backward in the rotation direction of the rotor; and a reluctor magnetic pole surface facing the magnetic pole portion of the rotation sensor is formed in each section; the tip of the first section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the tip of the first section passes through the position of the magnetic pole portion of the rotation sensor during the course of rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the one direction; a connecting portion between the rear end of the first section and the front end of the second section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the connecting portion passes through the position of the magnetic pole portion of the rotation sensor during the course of the rotor rotation, in order to change the signal generating magnetic flux in a stepwise manner in one direction; a connecting portion between the rear end of the second section and the front end of the third section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the connecting portion passes the position of the magnetic pole portion of the rotation sensor during the course of the rotor rotation, in order to change the signal generating magnetic flux in a stepwise manner in the other direction; the rear end of the third section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the rear end passes through the position of the magnetic pole portion of the rotation sensor during the rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the other direction; the first magnetic flux change generating unit is configured by a leading end of the first section and a connecting portion between a rear end of the first section and a leading end of the second section; the second magnetic flux change generating unit is configured by a connecting portion between the rear end of the second section and the front end of the third section, and the rear end of the third section.

2. The signal generating device according to claim 1.

5. 5. The signal generating device according to claim 4, wherein the reluctor further comprises another reluctor component comprising an arcuate protrusion or recess formed at a position spaced rearward in the direction of rotation from the rear end of the reluctor component.

6. the rotor has a cylindrical surface that is disposed in a state where the rotor and the crankshaft share a central axis when the rotor is attached to the engine, and the reluctor is provided on this cylindrical surface; The rotation sensor comprises a magnetic pole portion that faces, via a gap, an area of ​​the cylindrical surface of the rotor where a reluctor is provided, a magnet that causes a signal-generating magnetic flux to flow in a magnetic path formed between the rotor and the rotation sensor, and a signal generating portion that generates a signal indicating a level change every time the reluctor causes a change in the signal-generating magnetic flux during the process of rotation of the rotor, The reluctor comprises a first reluctor component consisting of a protrusion or recess having a first section with a constant width extending in the circumferential direction of the cylindrical surface with its leading end facing forward in the rotation direction of the rotor and its rear end facing rearward in the rotation direction of the rotor, and a second section with a constant width extending in the circumferential direction of the cylindrical surface with its leading end connected to the rear end of the first section and its rear end facing rearward in the rotation direction of the rotor; a second reluctor component consisting of a protrusion or recess having a third section that has a certain width and extends in the circumferential direction of the cylindrical surface with its front end facing forward in the rotation direction of the rotor and its rear end facing rear in the rotation direction of the rotor, and a fourth section that has a certain width and is connected to the rear end of the third section with its front end facing rear in the rotation direction of the rotor, and has a reluctor pole surface that faces the magnetic pole portion of the rotation sensor formed in each section; the tip of the first section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the tip of the first section passes through the position of the magnetic pole portion of the rotation sensor during the course of rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the one direction; a connecting portion between the rear end of the first section and the front end of the second section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the connecting portion passes the position of the magnetic pole portion of the rotation sensor during the course of the rotor rotation, in order to change the signal generating magnetic flux in a stepwise manner in one direction; the rear end of the second section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the rear end passes through the position of the magnetic pole portion of the rotation sensor during the rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the other direction; the tip of the third section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the tip passes the position of the magnetic pole portion of the rotation sensor during the rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the one direction; a connecting portion between the third section and the fourth section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the connecting portion passes the position of the magnetic pole portion of the rotation sensor during the course of the rotor rotation, in order to change the signal generating magnetic flux in a stepwise manner in the other direction; the rear end of the fourth section is formed so as to change the distance between the magnetic pole portion of the rotation sensor and the magnetic pole face of the reluctor or the area of ​​the magnetic pole face of the reluctor in a stepwise manner when the rear end passes through the position of the magnetic pole portion of the rotation sensor during the rotation of the rotor, in order to change the signal generating magnetic flux in a stepwise manner in the other direction; the first magnetic flux change generating unit is configured by a leading end of the first section and a connecting portion between a rear end of the first section and a leading end of the second section; the second magnetic flux change generating unit is configured by a connecting portion between the rear end of the third section and the front end of the fourth section, and the rear end of the fourth section.

2. The signal generating device according to claim 1.

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