JP2565547Y2 - Signal generator for internal combustion engine ignition system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal generator for an internal combustion engine ignition device which generates an ignition signal using a magnetic sensor.

[0002]

2. Description of the Related Art In general, an ignition device for an internal combustion engine is provided with a semiconductor switch for controlling a primary current on a primary side of an ignition coil, and the primary current of the ignition coil is controlled by turning off or conducting the semiconductor switch. A sudden change causes a high voltage to be induced in the secondary coil of the ignition coil, and the high voltage is applied to a spark plug attached to a cylinder of the engine to blow a spark. In order to determine the ignition position, a signal generator is attached to the internal combustion engine, and a signal obtained from the signal generator is used as an ignition signal, and the semiconductor switch is turned on or off by the ignition signal.

Various types of signal generators have been put to practical use, and one type using a magnetic sensor is known. FIG. 5 shows an example of an ignition circuit using this type of signal generator. In this ignition circuit, ignition energy is stored through a rectifier D by the output of an exciter coil EX provided in a magnet generator that rotates synchronously with the engine. Charge capacitor C for signal generation at the ignition position of the engine.
Supplies an ignition signal to a thyristor TH as a primary current control semiconductor switch. As a result, when the thyristor TH is turned on, the electric charge of the ignition energy storage capacitor C is discharged through the primary coil L1 of the ignition coil. As a result, a large change in magnetic flux occurs in the iron core of the ignition coil, and a high voltage is induced in the secondary coil L2. Since this high voltage is applied to the spark plug P, sparks fly to the spark plug and the engine is ignited.

The signal generator 3 comprises a magnetic sensor using a Hall element or a Hall IC, and a magnetic change is given to the magnetic sensor by a rotor that rotates synchronously with the engine. A DC drive voltage from a rectifier circuit or a battery that rectifies a part of the output of the exciter coil EX is applied to the input terminal (input terminal of the magnetic sensor) 3a of the signal emission, and the magnetic flux changes at the ignition position of the engine. Is applied, a signal voltage is obtained at the output terminal 3b of signal emission.

FIG. 6 shows the structure of a conventional signal generator using a magnetic sensor. This signal generator includes a rotor 1 having a reluctor 2 provided on the outer periphery of a rotating body made of a magnetic material, and a signal generator. It is composed of the electron emission 3. Signal emission 3
Is provided with an elongated rectangular plate-shaped yoke 10 in the circumferential direction of the rotor 1, and one magnetic pole (N pole in this example) of the permanent magnet 4 is coupled to one end of one surface of the yoke 10. I have. Yoke 1
One surface of the magnetic sensor 9 composed of a Hall IC is coupled to the other surface of the first surface of the magnetic sensor 0. The other magnetic pole (S-pole in this example) of the permanent magnet 4 and the other surface of the magnetic sensor 9 face the reluctor 2 via a gap.

In the above signal generator, the reluctor 2
7A, which does not face the magnetic pole (S-pole) of the permanent magnet 4 and the magnetic sensor 9, the N-pole of the permanent magnet 4 → the yoke, as indicated by the broken-line arrow in FIG. 10 → space 1
1 → Normal pole of permanent magnet 4 → Yoke 10 → Magnetic sensor 9 while leakage magnetic flux φa1 flows through the path of S pole of permanent magnet 4
→ space 11 → magnetic flux φs1 (magnetic flux density Bs1) leaking through the magnetic sensor 9 along the path of the S pole of the permanent magnet 4 also flows. When the rotor 1 rotates in the direction indicated by the solid arrow shown in FIG. 7 and the reluctor 2 is brought into the state shown in FIG. 7B in which the magnetic pole (S pole) of the permanent magnet 4 and the magnetic sensor 9 are opposed to each other, the broken line in FIG. As shown by the arrow, the N pole of the permanent magnet 4 → the yoke 10 → the space 11 →
Leakage magnetic flux φa2 flows through the path of the reluctor 2 → the S pole of the permanent magnet 4 and the magnetic sensor 9 passes through the path of the N pole of the permanent magnet 4 → the yoke 10 → the magnetic sensor 9 → reactor 2 → the S pole of the permanent magnet 4. Is a magnetic flux φs2 larger than the magnetic flux φs1 (magnetic flux density Bs
2) flows.

FIG. 8A shows how the magnetic flux density Bs of the magnetic sensor 9 changes with respect to the rotation angle θ of the rotor 1. FIG. 8B shows the change in the magnetic flux density. 3 shows a waveform of an electric signal output from the magnetic sensor 9 (Hall IC). In FIG. 8A, the magnetic flux density Bs of the magnetic sensor is equal to the output operation level of the Hall IC + Bt.
Is less than (L), the magnetic flux density Bs is smaller than the Hall I at the rotational angular position θ1.
When the output operation level of C reaches + Bt, the output of the magnetic sensor becomes a high level (H), and this high level electric signal output is supplied to the primary current control semiconductor switch of the ignition circuit as an ignition signal, and the rotation angle position is changed. Ignition occurs at θ1.

[0008]

In the above-mentioned conventional signal generator, the magnetic flux .phi.s1 (magnetic flux density Bs1) flows through the magnetic sensor even when the reluctor is not facing the permanent magnet and the magnetic sensor. Φs2-φs1 of magnetic flux of magnetic sensor caused by rotation of magnetic flux (fluctuation of magnetic flux density Bs2
−Bs1) generally becomes smaller. If the distance d between the permanent magnet and the magnetic sensor is reduced (see FIG. 7), the leakage magnetic flux φa2 decreases and the magnetic flux φs2 passing through the magnetic sensor increases when the reactor faces the permanent magnet and the magnetic sensor. However, in this case, when the reluctor is not facing the permanent magnet and the magnetic sensor, the magnetic flux φs1 passing through the magnetic sensor also increases, so that Bs1> Bt, and the signal generator may not operate normally. There is. According to experiments, it has been found that a signal with a value of d of 8 mm or less is not generated. Therefore, the distance d between the permanent magnet and the magnetic sensor cannot be selected to be too small. Therefore, the rotation angle required to change the magnetic flux density Bs of the magnetic sensor from Bs1 to Bs2 must be large, and the change amount Bs2-Bs1 of the magnetic flux density is also small.
The change rate of the magnetic flux density Bs of the magnetic sensor in the vicinity of the ignition position θ1 (the position where Bs = Bt) becomes smaller, and the variation in the gap length between the permanent magnet and the magnetic sensor and the reluctor and the magnetization amount of the permanent magnet are reduced. There is a problem that the signal generation position fluctuates due to the variation of the above, and the ignition position fluctuates.

An object of the present invention is to prevent a magnetic flux from flowing to a magnetic sensor in a state where the magnetic pole portion of the signal emission is not opposed to the reluctor, and to change the magnetic flux density of the magnetic sensor and the magnetic flux with respect to the rotation angle. An object of the present invention is to provide a signal generator for an ignition device of an internal combustion engine, which is capable of reducing a fluctuation range of a signal generation position by increasing a rate of change in density.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to an ignition system for an internal combustion engine having a rotor having a reluctor and a signal generator for outputting a signal in accordance with a change in magnetic flux generated in the magnetic sensor by the reluctor. In the signal generator, when the reluctor is not opposed to the magnetic pole portion of the signal emission, the magnetic flux hardly passes through the magnetic sensor, so that the change in the magnetic flux generated in the magnetic sensor can be increased.

[0011] Therefore, in the present invention, a permanent magnet, a magnetic sensor, a first and a second iron core having one end respectively connected to one magnetic pole surface and the other magnetic pole surface of the permanent magnet, A third iron core having one end coupled to one pole face of the permanent magnet is provided. And the magnetic sensor
And the other end of the first iron core and the other end of the second iron core are magnetic pole portions facing the rotor.

[0012]

As described above, when the magnetic sensor is disposed between the first and third iron cores having one end coupled to one of the magnetic pole surfaces of the permanent magnet, the reluctor is connected to the magnetic pole portions of the first and second iron cores. When not facing each other, the leakage magnetic flux generated by the permanent magnet hardly passes through the magnetic sensor. In a state where the reluctor is opposed to the magnetic poles of the first and second iron cores, the magnetic flux emitted from one magnetic pole of the permanent magnet has passed through the first iron core, the third iron core, and the magnetic sensor, respectively. It flows on the path leading to the other magnetic pole of the permanent magnet via the rear retractor and the second iron core. The amount of change in the magnetic flux of the magnetic sensor can be increased by increasing the amount of magnetization of the permanent magnet, and the distance between the magnetic pole portion of the first iron core and the magnetic pole portion of the second iron core should be selected to be small. Therefore, the rate of change of the magnetic flux (magnetic flux density) passing through the magnetic sensor with respect to the rotation angle can be increased. Therefore, the variation of the ignition timing can be reduced.

[0013]

1 shows the structure of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a rotor provided with a reluctor 2 on the outer periphery of a cylindrical rotating body made of a magnetic material. As a rotating body constituting the rotor 1, for example, a cup-shaped flywheel of a flywheel magnet rotor can be used.
In the case of using a cup-shaped flywheel, the reluctor 2 can be configured by projecting a part of the peripheral wall portion to the outside. The circumferential length of the reactor 2 is set to a predetermined value.

Reference numeral 3 denotes a signal generator fixed to a crankcase or the like of an internal combustion engine (not shown). The signal generator 3 and the rotor 1 constitute a signal generator for an internal combustion engine ignition device.

The signal generator 3 includes a plate-shaped permanent magnet 4 and a first permanent magnet 4.
And the third iron cores 5 and 8, the second iron core 6 integrally formed with the electron emission mounting portion 7, and the magnetic sensor 9. One end of each of the first iron core 5 and the third iron core 8 is bonded to one magnetic pole surface (in this example, the magnetic pole surface of the N pole) of the permanent magnet 4 by bonding, and the other end of the first iron core 5 Is a magnetic pole part 5 facing the reluctor 2 via a small gap.
It is 1. The second iron core 6 and the emission mounting portion 7 are integrally formed by an iron plate. The second iron core 6 is bent into an L-shape, and one end thereof is bonded to the other magnetic pole surface (in this example, the magnetic pole surface of the S pole) of the permanent magnet 4 by bonding, and the other end of the second iron core is connected to the reluctor 2. And a magnetic pole portion 61 which faces through a small gap. In the generator mounting part 7,
Two mounting holes 7a and 8b for screwing and fixing the signal generator 3 to a crankcase or the like of an engine (not shown) are provided.

The magnetic sensor 9 is arranged between the first core 5 and the third core 8. The magnetic sensor 9 is formed of a Hall IC. A constant DC voltage is applied to an input terminal of the magnetic sensor 9 from a power supply (not shown), and an electric signal is output to an output terminal of the magnetic sensor 9 in response to a unidirectional magnetic flux flowing through the Hall IC. Output.

In the state shown in FIG. 2A where the reluctor 2 does not face the magnetic pole portion 51 of the first iron core 5 and the magnetic pole portion 61 of the second iron core 6 for signal emission, the magnetic flux generated by the permanent magnet 4 is The N pole of the permanent magnet 4 → the side surface of the first iron core 5 → the space → the side surface of the second iron core 6 → the path of the S pole of the permanent magnet 4 and the N pole of the permanent magnet 4 → the third as indicated by the dashed arrow in the drawing. Iron core 8
Side → space → side surface of second iron core 6 → S-pole of permanent magnet 4 flows as leakage magnetic fluxes φr1 and φr2. Since these leakage magnetic fluxes hardly pass through the magnetic sensor 9, the magnetic flux φso (magnetic flux density Bso) of the magnetic sensor is almost zero.

The state shown in FIG. 2B in which the rotor 1 rotates in the direction indicated by the solid line arrow and the reluctor 2 faces the magnetic pole portion 51 of the first iron core 5 and the magnetic pole portion 61 of the second iron core 6. , The N pole of the permanent magnet 4 → the first iron core 5 → the magnetic pole part 51 → the reluctor 2 → the magnetic pole part 61, as indicated by the broken line arrow in FIG.
→ The second core 6 → the magnetic flux φsb flows along the path of the S pole of the permanent magnet 4, and the N pole of the permanent magnet 4 → the third core 8 → the magnetic sensor 9 → the first core 5 → the magnetic pole part 51 → reactor 2 →
The magnetic flux φsa flows through the path from the magnetic pole part 61 → the second iron core 6 → the S pole of the permanent magnet 4. Therefore, this magnetic flux φ
sa (magnetic flux density Bsa) flows in the direction of the arrow shown in the figure. The reason why the magnetic flux φsa flows is as follows. That is, one end of each of the first iron core 5 and the third iron core 8 is coupled to one magnetic pole surface (N pole surface) of the permanent magnet 4, but since the magnetic flux φsb is larger than the magnetic flux φsa, the permanent magnet The internal magnetic drop of the portion where the magnetic flux φsb of the permanent magnet 4 passes is larger than the internal magnetic drop of the portion where the magnetic flux φsa of the permanent magnet 4 passes. Therefore, a magnetic potential difference occurs between both ends of the magnetic sensor 9, and the magnetic flux φsa flows through the magnetic sensor 9.

FIG. 3A shows how the magnetic flux density Bs detected by the magnetic sensor 9 changes with the change of the rotation angle θ of the rotor 1. FIG. 3B shows a waveform of an electric signal output from the magnetic sensor (Hall IC) 9 according to the change in the magnetic flux density.

While the magnetic flux flows in the magnetic sensor 9 in one direction, the magnetic flux density Bs increases, and the rotational angle position θ 1 of the rotor 1 is increased.
In this case, when the magnetic flux density Bs reaches the output operation level + Bt of the Hall IC, the output of the magnetic sensor becomes high (H).
When the magnetic flux density Bs becomes smaller than the output operation level + Bt of the Hall IC at the rotation angle position θ2, the output of the magnetic sensor becomes low (L). When a high-level electrical signal output is supplied to the primary current control semiconductor switch of the ignition circuit as an ignition signal, an ignition operation can be performed at the rotational angle position θ1.

Since the magnetic flux density Bso of the magnetic sensor 9 is almost zero when the retractor 2 is not opposed to the magnetic pole part 51 of the first iron core 5 and the magnetic pole part 61 of the second iron core 6, the permanent magnet 4 is increased and the reluctor 2
In addition, if the magnetic flux density Bsa of the magnetic sensor 9 in a state of facing the magnetic pole portions 51 and 61 of the second iron core is increased, the variation Bsa-Bso of the magnetic flux density of the magnetic sensor 9 can be increased. The distance g (see FIG. 2) between the magnetic pole part 51 and the magnetic pole part 61 is selected to be small, and the magnetic flux density Bs of the magnetic sensor 9 is a value near the output operation level of the Hall IC + Bt. Since the rate of change with respect to the rotation angle θ can be increased, the variation in the ignition angle position θ1 can be reduced. According to the experimental results, it has been confirmed that the signal generator operates normally even when g = 4 mm by employing the above configuration.

In the above embodiment, the magnetic sensor 9 is constituted by a Hall IC. However, a Hall element may be used as a magnetic sensor, and an amplifier circuit and a waveform shaping circuit may be connected to the output side as necessary. Good.

In the above embodiment, the ignition is performed at the rotation angle position θ1 by using the high level electric signal output obtained at the output end of the magnetic sensor as the ignition signal.
A waveform inverting circuit is connected to the output end of the magnetic sensor, and the low-level electric signal output obtained at the output end of the magnetic sensor is inverted by the waveform inverting circuit, and the high-level electric signal obtained at the output end of the waveform inverting circuit is inverted. By supplying the signal output to the primary current control semiconductor switch 4 of the ignition circuit as an ignition signal, ignition can be performed at the rotational angular position θ2.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the permanent magnets are arranged with the direction of magnetization of the permanent magnets 4 oriented in the circumferential direction of the rotor 1. Further, the first core 5 and the second core 6 are formed in an I-shape, the third core 8 is formed in an L-shape, and the first core is provided on one of the pole faces and the other pole face of the magnet 4, respectively. 5 is connected to one end of the second core 6, and one end of the third core 8 is connected to one pole face of the magnet 4.
A magnetic sensor 9 is disposed between the magnetic sensor 9 and the third iron core 8.
The operation of this embodiment is the same as the operation of the embodiment shown in FIG.

[0025]

As described above, according to the present invention, the amount of change in the magnetic flux density of the magnetic sensor and the rate of change with respect to the rotation angle caused by the reluctor can be increased. Between the gaps between
The variation width of the signal generation position due to the variation of the magnetizing amount of the magnet can be reduced. Therefore, by using the signal generating device of the present invention for the ignition device, the variation of the ignition position can be reduced.

[0026]

[Brief description of the drawings]

[0027]

FIG. 1 is a perspective view showing a structure of a main part of an embodiment of the present invention.

[0028]

FIG. 2 shows a main part of an embodiment of the present invention, and (A)
(B) is a front view in a state where the reluctor does not face the magnetic pole portion of the signal emission and in a state where it faces the magnetic pole portion.

[0029]

3A is a diagram showing a change in magnetic flux density of the magnetic sensor in the embodiment of FIG. 1, and FIG. 3B is a diagram showing a waveform of an output signal of the magnetic sensor.

[0030]

FIG. 4 is a front view showing a main part of another embodiment of the present invention.

[0031]

FIG. 5 is a connection diagram showing an example of an ignition circuit used in the present invention.

[0032]

FIG. 6 is a perspective view showing a structure of a main part of a conventional example.

[0033]

7 (A) and 7 (B) are front views showing a main part of a conventional example, in which a reluctor is not facing a permanent magnet and a magnetic sensor for signal emission and in a state where it is facing, respectively. It is.

[0034]

8A is a diagram showing a change in magnetic flux density of the magnetic sensor in the conventional example of FIG. 6, and FIG. 8B is a diagram showing a waveform of an output signal of the magnetic sensor.

[0035]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Reluctor 3 Signal generation 4 Permanent magnet 5 1st iron core 51 Magnetic pole part of 1st iron core 6 2nd iron core 61 Magnetic pole part of 2nd iron core 8 3rd iron core 9 Magnetic sensor

Claims (1)

(57) [Scope of request for utility model registration] 1. A signal generator for an internal combustion engine ignition device comprising: a rotor having a reluctor; and a signal generator that outputs a signal in accordance with a change in magnetic flux generated by the reluctor. , A permanent magnet, first and second cores each having one end coupled to one pole surface and the other pole surface of the permanent magnet, and a third core having one end coupled to one pole surface of the permanent magnet. And a magnetic sensor disposed between the first and third iron cores, the other end of the first iron core and the other end of the second iron core facing the rotor. A signal generator for an internal combustion engine ignition device, comprising: