JPS586066B2 - Non-contact ignition device for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-contact ignition device for an internal combustion engine that obtains a high voltage by controlling the primary current of an ignition coil using a semiconductor switch.

Generally, in non-contact ignition devices for internal combustion engines, one of the ignition coils
A semiconductor switch for controlling the primary current, such as a cyrisk or a transistor, is installed on the next side, and the semiconductor switch is operated by the ignition timing signal generated at the ignition position of the internal combustion engine to suddenly change the primary current of the ignition coil. Generate voltage.

The power source for this type of ignition system is the output shaft of an internal combustion engine (
A reciprocating engine uses a magnet generator with a rotor attached to the crankshaft, and in many cases, the signal generator coil that generates the above-mentioned ignition timing signal is also built into the magnet generator.

A magnet generator attached to an internal combustion engine is generally configured to have multiple poles of four or more poles, since the load includes a headlamp, battery charging circuit, etc. in addition to the ignition device.

Therefore, if the ignition timing signal generating coil is simply arranged in the same way as other generating coils in this magnet generator,
This signal generating coil generates a signal multiple times during one revolution of the engine's output shaft, and if this signal is supplied as is to the ignition system, multiple sparks are generated during one revolution of the engine's output shaft, causing ignition. There will be unnecessary fire in the engine at a position other than the position.

Particularly in the case of a four-stroke engine, it is required to completely prevent such wasted flames from flying.

Conventionally, a part of the magnetic pole piece of the rotor of a magnet generator is extended to form signal magnetic poles aligned in the axial direction of the rotor, and the signal generation coil is arranged to work only with these magnetic poles. A signal generating device has been proposed in which a part of the magnetic poles of a flywheel magnet rotor is led out to the outer periphery of the flywheel, and a signal generating coil is arranged to face the led out magnetic pole.

According to these signal generators, since only one signal is generated during one revolution of the rotor, the ignition operation of one ignition per revolution can be performed without any problem.

However, on the other hand, it is necessary to partially deform or extend the magnetic pole piece, which not only makes it difficult to manufacture the generator, but also generates noise due to the influence of the main magnetic pole of the magnet generator. The drawback was that the ignition system malfunctioned.

An object of the present invention is to provide a non-contact ignition device for an internal combustion engine that allows one ignition operation to be performed per rotation without deforming the magnetic pole pieces of the rotor of a magnet generator. It is in.

The present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 1 shows an example of a magnet electric machine used in the present invention, and in the figure, 1 is an iron bowl-shaped flywheel.

The flywheel 1 has a boss 2 for attaching a rotating shaft in the center of its bottom wall, and this boss is usually fitted and keyed to an output shaft (not shown) of an engine.

On the inner circumferential surface of the flywheel 1, there are four magnets 3a to 3.
d are attached, and magnetic pole pieces 4a to 4d are attached to the inner peripheral surfaces of these magnets, respectively.

These magnets and magnetic pole pieces are attached by suitable means such as screws, rivets, or adhesives that pass through the magnets and connect the flywheel and the magnetic pole pieces.

The magnets 3a to 3d are magnetized in the radial direction so that magnetic poles of different polarities are arranged alternately in the circumferential direction of the flywheel, and the flywheel magnet rotor 5 is formed by the flywheel 1, the magnets 3a to 3d, and the magnetic pole pieces 4a to 4d. is configured.

In a typical magnet generator, the magnetic poles of the rotor are arranged symmetrically at equal angular intervals, but in the present invention, a portion of the magnetic poles of the rotor are shifted to make the magnetic circuit asymmetrical.

That is, in the embodiment shown in FIG. 1, the two adjacent magnets 3c and 3d among the magnets 3a to 3d are moved by an angle α relative to the position where the magnets 3a to 3d are arranged symmetrically at equal angular intervals. They are staggered toward each other.

Therefore, the angular spacing between magnets 3b and 3c and the magnets 3d and 3a
The angular distance between the magnets 3c and 3d is 90°+α, and the distance between the magnets 3c and 3d is 90°−2α.

If the magnets are attached asymmetrically in this way, the balance of the weight of the rotor will be lost, so a biran weight 6 is attached between the magnets 3a and 3b.

The stators cooperating with the magnet rotor 5 mentioned above are 180 degrees apart from each other.
Two signal armatures 7 arranged symmetrically with an angular interval of degrees
a and 7b, and an armature 8 arranged axially side by side with one signal armature 7a (see FIG. 2).

). The signal armatures 7a and 7b are each made up of substantially ■-shaped iron cores 71a and 71b having a polar arc angle of 90 degrees, and signal generator coils 72a and 72b are wound around them, and the armature 8 is made of the same type as above. It consists of a generator coil 82 wound around a character-shaped iron core 81.

These armatures are attached by passing screws through holes 9 provided at both ends of each iron core, and screwing the screws into a base plate provided at a fixed position on the cover of the engine or the like.

The armature 8 is, for example, a power source for supplying a primary current to an ignition coil, and when a capacitor charge/discharge type ignition circuit is used, it is used as a power source for charging the capacitor.

It is also possible to arrange another armature on the signal armature 7b side so as to be aligned with this armature in the axial direction, and to load this armature with a headlamp or the like.

In the actual case shown in FIGS. 1 and 2, since the magnetic circuit is asymmetrical, a phase shift occurs in the magnetic fluxes φa and φb interlinking with the signal generating coils 72a and 72b, and accordingly, the generated voltages Va and A shift also occurs in the phase of Vb.

FIGS. 3A and 3B show the magnetic fluxes φa and φb when the rotor is rotated in the direction of the arrow in FIG. 1, and the signal generator coil 7.
The waveforms of the signal voltages Va and vb obtained at 2a and 72b are shown with respect to the rotation angle θ of the rotor.

That is, first, in a certain positive half cycle, the signal voltage Va reaches its peak value at an angle θ1, but the signal voltage Vb reaches a peak value at a position θ1' (=θ1-α) where the phase is advanced by α from the angle θ1.
) reaches its peak value.

In the next positive half cycle, the signal voltage Vb reaches its peak value at the angle θ3, but the signal voltage Va is at a position θ′3 (=θ3−α) where the phase is advanced by α from this angle θ3.
The peak value is reached at .

Since the signal generating coils 72a and 72b each generate two cycles of signals during one revolution of the rotor, each signal can be generated even if only one half cycle is extracted by passing the output of these signal generating coils through a diode. Two signals are generated per rotation in the generator coil.

However, if the phases of the two signal voltages are in a relationship where they alternately lead and lag as described above, as shown below, the signal voltage vb whose phase is advanced and reaches its peak value at the angle θ1'
By canceling the signal voltage Va and using the phase-advanced signal voltage Va that reaches its peak value at the angle θ3 as the ignition timing signal, it is possible to perform one ignition operation per revolution.

FIG. 4 shows an embodiment of the ignition device of the present invention, which uses the magnet generator shown in FIGS. 1 and 2 to perform an ignition operation of one ignition per rotation.

In FIG. 4, reference numeral 11 denotes an ignition plug having a primary coil 11a and a secondary coil 11b. An ignition coil 12 is connected to both ends of the secondary coil 11b and is attached to the cylinder of the engine.

13 is a capacitor connected in series to the primary coil 11a, 14 is a thyristor as a semiconductor switch for primary current control connected in parallel to both ends of the series circuit of the primary coil 11a and the capacitor 3; A power generating coil 8 shown in FIG. 2 is connected to both ends via a diode 15.
2 are connected in parallel.

A diode 1 is connected between the gate and cathode of the thyristor 14.
A signal generating coil 72a shown in FIG. 1 is connected in parallel as a signal generating coil for ignition timing via 6, and a thyristor 17 as a semiconductor switch for signal bypass is connected in parallel to both ends of the signal generating coil 72a.

Further, a signal generating coil 72b is connected in parallel between the gate and cathode of the thyristor 17 via a diode 18 as a signal generating coil for a signal side path.

In the ignition system shown in FIG. 4, the capacitor 3 is charged to the polarity shown in the figure by a half wave of the output of the generating coil 82, and when an ignition signal is given to the thyristor 14 at the ignition position, the thyristor 14 becomes conductive and the capacitor 13 The electric charge is discharged to the primary coil 11a.

As a result, a high voltage is generated in the secondary coil 11b, and a spark is generated in the ignition plug 12.

Now set the gate trigger level of thyristors 14 and 17 as eg
Then, the angle θ shown in FIG.

When the rotor 5 rotates from , first, the signal voltage Vb reaches the trigger level eg earlier than the signal voltage Va at the angle β1, and the thyristor 17 to which a forward voltage is applied between the anode and cathode becomes conductive due to the signal voltage Va. do.

Due to the conduction of this thyristor 17, the signal generating coil 72a
Since the thyristor 14 is short-circuited, no firing signal is given to the thyristor 14.

When the signal voltage Va reaches the trigger level e2 earlier than the signal voltage Vb at β2, the thyristor 14 becomes conductive, the capacitor 3 discharges through the thyristor 14 and the primary coil 11a, and ignition is performed.

Subsequently, at angle β3, signal voltage Vb reaches trigger level e.
g and the thyristor 17 becomes conductive, but at this time the thyristor 14 is already conductive and ignition has taken place, so
It has no effect on ignition operation.

In this way, when the ignition system is configured as shown in FIG. 4 using the magnet generator shown in FIG.
The ignition operation can be performed twice.

In the above embodiment, the positions of two magnets 3c and 3d among the four magnets 3a to 3d are shifted, but only one magnet, for example, magnet 3c, is moved at an angle as shown in FIG. It is also possible to shift by α.

In this case, the waveforms of the magnetic fluxes φa, φb and the signal voltages Va, Vb are as shown in FIGS. 6A and 6B, and results exactly the same as in the case shown in FIG. 1 can be obtained.

The purpose of the present invention can be achieved by simply shifting one magnet in this way, but in order to make it easier to balance the weight of the rotor, it is desirable to shift two magnets as shown in Figure 1. .

In each of the above embodiments, the magnet generator has four poles, but the present invention can be implemented using a general 2n (n is an integer of 2 or more) pole magnet generator.

In other words, when a 2n-pole magnet generator is used, the position of some of the magnetic poles of the 2n-pole magnet rotor is shifted to make the magnetic circuit asymmetrical, and n signal generator coils are arranged symmetrically so that one of them By using one signal generating coil as a signal generating coil for ignition timing and using the other signal generating coil as a signal generating coil for signal bypass, it is possible to perform an ignition operation of one ignition per rotation.

FIG. 7 shows a case where the magnet generator is configured with six poles (n=3), and six magnets 3a to 3f are attached to the inner peripheral surface of the flywheel 1. Magnetic pole pieces 4a to 4f are arranged on the circumferential surface, respectively.

The position of one magnet 3d among the six magnets 3a to 3f is shifted by an angle α, thereby making the magnetic circuit asymmetrical.

Three signal armatures 7a to 7c are arranged symmetrically at angular intervals of 120 degrees, and each armature has a signal generator coil 72a to 72c wound around a ■-shaped iron core 71a to 71c with a polar arc angle of 60 degrees. consists of things.

Further, an armature 8 (not shown in FIG. 7) is arranged so as to be aligned with the signal armature 7a in the axial direction of the rotor.

In this embodiment as well, other signal armatures 7b and 7
It is possible to arrange other armatures in axial alignment with c and load lamps or the like onto these armatures.

Assuming that the magnetic fluxes interlinking with the signal generating coils 72a to 72c in FIG. 7 are respectively θa, φb, and φc, and the signal voltages induced in these generating coils are Va, vb, and Vc, the waveforms for these rotation angles θ are as follows. The state is as shown in FIGS. 8A to 8C.

Therefore, the signal voltage Va that reaches its peak at angles θ1 and θ3 is expressed by angles θ1' (= θ1 - α) and θ'3 (
By canceling out the signal voltages Vc and vb that reach their peak at angle θ = θ3-α), and using the half cycle of the signal voltage Va that reaches its peak at angle θ = θ5-α) as the ignition timing signal, the ignition operation of one ignition per revolution is achieved. I can make you do it.

FIG. 9 shows an embodiment of the ignition system when using the magnet generator shown in FIG. The other two signal generating coils 72b and 72c are connected between the gate and cathode of the thyristor 14, and the other two signal generating coils 72b and 72c are connected to the thyristor 17 through an OR circuit consisting of diodes 18 and 19 as signal generating coils for signal bypass.
connected between the gate and cathode.

Other points are the same as in FIG. 4.

With this configuration, the signal voltage Va that reaches its peak at angles θ1 and θ3 is short-circuited and canceled by the thyristor 17 triggered by the signal voltage Vc or vb, and only half a cycle of the signal voltage Va reaches its peak at angle θ'5. is given to the thyristor 14 as an ignition timing signal.

In the above embodiment, each signal generating coil is wound around a ■-shaped iron core, but it may be wound around an annular star-shaped salient pole-shaped iron core in which the magnetic poles are symmetrically arranged.

Further, each signal generating coil may be directly wound on a generating coil that supplies power to a headlamp or a battery charging circuit.

In addition, in the above explanation, a capacitor charge/discharge type point circuit was used as the ignition circuit, but a semiconductor switch for primary current control such as a transistor is inserted in series or parallel with the primary coil of the ignition coil, and the switch is turned on and off. The present invention can be applied in exactly the same way even when a so-called primary current cutoff type ignition circuit that suddenly changes the primary current is used.

Furthermore, in the above embodiment, a plurality of magnets are attached to the flywheel, but the same result can also be obtained by fitting a ring-shaped magnet to the inner circumference of the flywheel and magnetizing the magnet asymmetrically. be able to.

Furthermore, the magnet generator used in the present invention is not limited to the external rotor type in which the rotor is disposed outside the stator as in the above embodiment;
It can also be configured as an internal rotation type in which the rotor is placed inside.

As described above, according to the present invention, it is only necessary to make the magnetic circuit asymmetric by shifting the position of some of the rotor magnetic poles of the magnet generator. This simplifies the structure of the generator and ensures that one ignition operation is performed per rotation.

Further, since noise is not generated unlike when a signal generator built into a magnet generator is used, malfunction of the ignition device can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a configuration example of a magnet generator used in the present invention, FIG. 2 is a perspective view illustrating the arrangement of the armature in the generator of FIG. 1, and FIGS. A diagram showing the magnetic flux and signal voltage waveforms in the generator shown in Figure 4.
A connection diagram showing an example of an ignition system using the generator shown in the figure.
FIG. 5 is a schematic configuration diagram showing another configuration example of the magnet generator used in the present invention, FIGS. 6A and B are diagrams showing magnetic flux and signal voltage waveforms in the generator of FIG. 5, and FIG. A schematic configuration diagram showing still another configuration example of the magnet generator used in the present invention, FIGS. 8A to C are diagrams showing magnetic flux and signal voltage waveforms in the generator of FIG. 7, and FIG. FIG. 2 is a connection diagram showing an example of an ignition device using a magnet generator. 1...Flywheel, 3a-3f...Magnet, 7a-7
c...Signal armature, 71a-71c...Iron core, 72a
~72c...Signal generation coil, 11...Ignition coil, 1
3... Capacitor, 14... Thyristor (semiconductor switch for primary current control), 17... Thyristor (semiconductor switch for signal bypass).

Claims (1)

[Claims] 1. A semiconductor switch for primary current control equipped with a control input terminal is provided on the primary side of the ignition coil, and a magnet having a 2n (n is an integer greater than or equal to 2) pole magnet rotor driven by the output shaft of an internal combustion engine. In a non-contact ignition device for an internal combustion engine, the primary current control semiconductor switch is controlled by the output of an ignition timing signal generation coil built into a generator, by shifting a part of the magnetic poles of the magnet rotor. The magnetic circuit is made asymmetric and n signal generating coils are arranged symmetrically so as to face the magnetic poles of the magnet rotor,
One of the n signal generating coils is used as the ignition timing signal generating coil.
A signal bypass semiconductor switch is connected to the next current control semiconductor switch and has a control input terminal in parallel with this signal generation coil, and other n-1 signal generation coils other than the one signal generation coil are A non-contact ignition device for an internal combustion engine, characterized in that the signal generating coil is connected to the control input terminal of the signal bypass semiconductor switch via a diode.