JPS61101674A - Contactless ignition device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the ignition performance of the device by a method wherein a revolving number sensitive conduction precluding circuit, precluding the conduction of a semiconductor switching element for short-circuiting the generating output of charging coil of a capacitor for a magnetic generator when the revolving number of the engine has become higher than a predetermined value, is equipped in the ignition device. CONSTITUTION:The base of a transistor Tr6 for interception control is connected to the potential dividing point (a) of potential dividing resistors 4, 5 directly connected between terminals of the capacitor charging coil 1 of the magnetic generator while the transistor Tr6 is also connected between the base emitters of the transistor Tr8, short-circuiting the forward output of the transistor Tr6 or the coil 1. A revolving number detecting circuit 9, inputting the output signal of a timing sensor 2 generating an output signal at a reference position and generating a conduction output when the revolving number of the engine has become higher than a predetermined value, is equipped in the device. On the other hand, another transistor 10, being conducted by the conducting output of said circuit 9 and short- circuiting the base current of the transistor Tr8, is equipped in the device while the revolving number sensitive conduction precluding circuit is constituted of said detecting circuit 9 and the transistor Tr10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capacitor discharge type non-contact ignition device for an internal combustion engine.

[Conventional technology]

Conventionally, as described in Japanese Unexamined Patent Publication No. 57-131864, the generated output of the capacitor/charging coil of a magnet generator is short-circuited by a short-circuiting semiconductor switching element, and when the short-circuit current exceeds a predetermined value, cut-off control is performed. By short-circuiting the control signal of the short-circuiting semiconductor switching element by the short-circuiting semiconductor switching element, and charging the capacitor with the high voltage induced in the charging coil when the short-circuiting semiconductor switching element is cut off due to the short-circuit of the control signal,
It is known that a capacitor is charged using a charging coil with a thick wire diameter and a small number of turns.

[Problem that the invention seeks to solve]

However, in the conventional system described above, as the rotational speed of the internal combustion engine increases, the voltage generated in the capacitor charging coil increases, and the current in the semiconductor switching element for cut-off control and its control circuit increases, and the capacitance of these heat sinks and elements increases. The problem was that it had to be made larger.

In addition, due to the increase in the cut-off current of the charging coil, the coil generates more heat (which means that copper wire with high heat resistance must be selected, and the output of the magnet generator is limited due to heat generation, making it difficult to increase the output). First, there were problems such as a reduction in the degree of freedom in design, increased circuit study time, and the discontinuation and unification of mass production of magnet generators.

Therefore, the present invention can ensure sufficient capacitor voltage from low speed to high speed, and furthermore, the capacitor charging coil can be a high speed capacitor charging coil with a small number of turns, and can be made thicker, so that it will not break due to vibrations of the internal combustion engine. ,Also,
This also makes it possible to reduce the heat generated by the semiconductor switching element for cut-off control and the capacitor charging coil.

[Means for solving problems]

Therefore, the present invention is provided with a rotational speed responsive conduction blocking circuit for preventing conduction of the shorting semiconductor switching element when the engine rotational speed exceeds a predetermined value.

[Effect]

As a result, the shorting semiconductor switching element is turned on and off only when the rotation speed is below the set value, and the capacitor is charged by the transient voltage when the current is cut off, and when the rotation is above the set value, the capacitor is charged using the voltage originally generated in the capacitor charging coil. do.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

In the first embodiment shown in FIG. 1, 1 is a capacitor charging coil of a magnet generator. 2 is a timing sensor that generates an output signal at a reference position, 4.5 is a voltage dividing resistor connected in series between the terminals of the capacitor charging coil 1, and the voltage dividing point a is connected to the base of the transistor 6. .

This transistor 6 is connected between the base and emitter of the transistor 8. Reference numeral 7 designates a base resistor of the transistor 8, and reference numeral 11 designates an ignition timing control circuit that receives the output signal of the timing sensor 2 as an input, calculates the ignition timing electronically, and generates an ignition signal. Further, the transformer and the distal transistor constitute a semiconductor switching element for cutoff control that short-circuits the base of the transistor 8, and the transistor 8 constitutes a semiconductor switching element for short-circuiting that short-circuits the forward output of the coil 1. 13 is an ignition capacitor; 9 is a rotation speed detection circuit that receives the output signal of the timing sensor 2 as an input and generates a conduction output when the engine rotation speed exceeds a predetermined value; and 10 is made conductive by the continuity output from the rotation speed detection circuit 9. This is a transistor that short-circuits the base current of transistor 8.

The rotation speed detection circuit 9 and the transistor 10 constitute a rotation speed responsive conduction blocking circuit. 12 is a discharge blocking diode, 14 is a diode that bypasses the reverse polarity half-wave output applied to transistor 8, 15 is a DC arc diode, 16 is an ignition coil, 16a is its primary coil, and 16b is its secondary coil. be. The capacitor 13 and the ignition coil 16 are connected in series, and the DC arc diode 15 is connected in parallel to the primary coil 16a.

Reference numeral 17 indicates an ignition plug, and 18 indicates an ignition sirisk which is a semiconductor switching element for ignition, and conducts when the ignition signal from the ignition advance control circuit 11 is applied to the gate, transferring the charge in the capacitor 13 to the ignition coil 16. It is supplied to the primary coil 16a of. 20 is a capacitor that is energized via a diode 26.14 by the negative half-wave output of the capacitor charging coil 1, and the ignition advance control circuit 11
19 is an energizer diode to prevent the superelectric voltage of the capacitor 20 from exceeding a set value, and 27 is a diode that bypasses the Zener diode 19 to charge the capacitor 13. .

Next, the structure of the magnet generator used in this example will be explained. In Fig. 2, 30 is a bowl-shaped coater, 31 is fixed to the inner circumferential surface of the rotor 30, and is magnetized with 12 poles at equal intervals as shown in the figure by a main magnet in the form of a square. be.

Reference numeral 32 denotes a ring-shaped stator core fixed to the side wall of the internal combustion engine, and twelve protrusions 323 to 32β are formed at equal intervals on the outer periphery of the stator core. 33 is 10 protrusions 32C~
The lamp load coils each have a number of windings connected to each other in series, and serve as a power source for a load such as a lamp. A boss 34 is fixed to the crankshaft of the internal combustion engine by a bolt (not shown), and the rotor 30 is fixed to the boss 34 via a coating head (not shown). 35 is an ignition signal timing sensor fixed to the side wall of the internal combustion engine on the outer periphery of the rotor 30, and includes a permanent magnet 35a magnetized in the radial direction, a core 35b fixed to the permanent magnet 35a, and a sensor wound around the core 35b. It consists of coil 2.

Reference numeral 36 denotes a protrusion made of a magnetic material provided on the outer circumference of the rotor 30. A core 35b is held in a position facing the protrusion 36, and a change in magnetic flux caused by the core 35b and the protrusion 36 facing each other causes a sensor Coil 2 receives an output voltage. The capacitor charging coil 1 has two protrusions 32a,
32b and connected to each other in series, the main magnet 3
With one rotation, six cycles of no-load AC voltage are generated in the capacitor charging coil 1 per one rotation of the rotor of the magnet generator.

Now, when a half-wave output in the direction of the arrow in Fig. 1 (positive direction) begins to be generated in the charging coil 1, one resistor 7 =
In the base emitter earth circuit of transistor 8,
The collector and emitter of transistor 8 are electrically connected by the base current flowing through transistor 8, and the output of coil 1 is short-circuited via diode 27. At this time, as the short-circuit current of transistor 8 increases, the voltage drop between the collector and emitter of transistor 8 increases,
The voltage at the connection point a of the voltage dividing circuit made up of resistors 4.5 rises. This voltage is set value (for example, short circuit current is 0.5 to 4A)
When the voltage value corresponds to ), the transistor 6 becomes conductive.
Since the base and emitter of transistor 8 are shorted,
The voltage between the collector and emitter of the transistor 8 is 0FFL, and the short circuit current is abruptly cut off. At this time, a large transient voltage is generated in the coil 1, and this high voltage causes the capacitor 13 to
is charged in the circuit of coil 1 → diode 12 → capacitor 13 - diode 15 - ground - diode 27.

Here, when the induced voltage induced in the charging coil 1 is relatively low, such as when the engine speed is low, a conduction output is not generated in the rotation speed detection circuit 9. The capacitor 13 is charged multiple times by the transient voltage of the charging coil 1 that occurs twice.

On the other hand, when the high voltage induced in the charging coil 1 becomes relatively high when the engine rotates at medium to high speeds, a conduction signal is generated from the rotational speed detection circuit 9 and connected between the base and emitter of the transistor 8. The transistor 10 is made conductive, and the base and emitter of the transistor 8 are short-circuited. As a result, the transistor 8 is not conductive, and henceforth, the positive half-wave output generated in the charging coil 1 directly charges the capacitor 13 via the diode 12.

In this way, when the high voltage induced in the charging coil 1 is relatively high, such as during medium and high speeds of the engine, the transistor 8
By preventing the conduction of the transistor, heat generation in the transistor can be suppressed and thermal runaway can be prevented.

Further, when the ignition timing comes, the thyristor 18 is made conductive by the ignition signal generated in the ignition advance control circuit 11, and the charge in the capacitor 13 is transferred from the capacitor 13 to the thyristor 18.
- Earth→A sudden discharge is caused in the circuit of the primary coil 16a of the ignition coil 16, a high voltage is obtained in the secondary coil 16b of the ignition coil 16, and an ignition spark is generated at the ignition plug 17.

In addition, due to the negative half-wave output generated in the charging coil 1,
The power supply capacitor 20 of the ignition charge control circuit 11 is charged via the diode 14.26.

Here, the Zener diode 19 is a constant voltage control element of the power supply capacitor 20.

FIG. 3 shows a second embodiment of the device of the present invention. In contrast to the first embodiment shown in FIG. 1, a resistor 21 is connected between the emitter of transistor 8 and the ground, and the base of transistor 8 is An anode-gate path of a thyristor 24 and a resistor 22 are connected between the emitters. The resistor 21 and the resistor 22 constitute a detection circuit, and when a high current flows between the collector and emitter of the transistor 8 due to conduction of the transistor 8, the thyristor 24 is made conductive through the resistor 21 and 22, and the transistor 8 is cut off. are doing. Further, a transistor 10 is connected between the base of the transistor 8 and ground. When the high voltage induced in the charging coil 1 becomes relatively high when the engine rotates at medium and high speeds, a conduction signal is generated from the rotational speed detection circuit 9 and the transistor 10
is made conductive, and the base of transistor 8 is shortened.

As a result, the transistor 8 is not conductive, and from then on, the positive half-wave output generated in the charging coil l is directly connected to the diode 27.
．． A capacitor 13 is charged via 12. Further, when the engine speed becomes low, the rotational speed detection circuit 9 no longer generates a conduction signal, and the transistor 8 repeatedly turns on and off.

26 is a diode for gate rectification.

FIG. 4 shows the configuration of main parts in a third embodiment of the device of the present invention, in which the transistor 10 is omitted from the first embodiment shown in FIG. The current is supplied directly to the base of the transistor 6 through the transistor 6, and by making the transistor 6 conductive, the transistor 8 is prevented from being conductive. Here, 28 and 29 are diodes for blocking backflow.

FIG. 5 shows an example of the internal configuration of the rotation speed detection circuit 9 applied to each of the above embodiments, in which a bias resistor 91
~93, capacitor 94, charging resistor 9 of capacitor 94
5. Dividing resistors 96-98, data flip-flop 99
and comparators 100 to 102.

FIG. 6 shows waveform diagrams of various parts of the circuit shown in FIG.
al is the output obtained by biasing the output signal of the sensor 2 with the bias resistors 91 to 93, (bJ is the operating output signal of the comparator 100, (C) is the operating output signal of the comparator 101, (the solid line and the broken line of dl are the output signal at low engine speed and The terminal voltage of the capacitor 94 at high speed, the one-dot chain line is the non-inverting input voltage (set voltage) of the comparator 102 set by the dividing resistors 96 to 98, and the solid and broken lines for te+ are the comparator 10 at low and high engine speeds.
The solid line and broken line of the operating output signal (fl) of 2 are the output signals of the flip-flop 99 when the engine speed is low and when the engine is high.

Next, the operation of the rotation speed detection circuit 9 will be explained.

The capacitor 94 is connected every time a negative direction output occurs to the sensor 2.
The charging charge is set and charging starts. Therefore,
When the engine speed is low, the cycle of the negative direction output generated by the sensor 2 is long, so the capacitor 94 is charged to a voltage higher than the set voltage of the comparator 102 before the positive direction output of the sensor 2 is generated, as shown by the solid line in Fig. 6+d). The output of this comparator 102 becomes a low level as shown by the solid line el in FIG.

As a result, a positive direction output is generated in the sensor 2 and a high level output signal is generated in the comparator 100. Even if this signal is applied to the clock terminal cp of the flip-flop 99, the data terminal of this flip-flop 99 is Since the level is already low, a low level output is generated at the Q output terminal as shown by the solid line in FIG. 6 (fl).

On the other hand, as the engine speed increases, the cycle of the negative direction output generated in the sensor 2 becomes shorter, and when the engine speed exceeds the set value, the capacitor 94 is
As shown by the broken line in d), the comparator 102 is no longer charged to the set voltage before the sensor 2 generates a positive output. As a result, even if a positive output is generated in the sensor 2 and a high-level output signal is generated in the comparator 100, the output signal of the comparator 102 remains at a high level as shown by the broken line in FIG. 6(e). Therefore, a high level output signal is generated at the Q output terminal of the 7-resopflossop 99 as shown by the broken line in FIG. 6(f).

This high-level output signal then becomes a conduction signal.

Note that the rotational speed detection circuit 9 is not limited to the one shown in FIG. 5; any circuit may be used as long as it generates a conduction signal when the engine rotational speed exceeds a predetermined value.

〔Effect of the invention〕

As described above, in the present invention, the shorting semiconductor switching element is turned on and off only when the rotation speed is low below the set value, and the capacitor is charged by the transient voltage when the current is cut off, and when the rotation speed is above the set value, the capacitor charging coil is charged. Since the capacitor is charged with the voltage that is originally generated, it is possible to secure sufficient capacitor voltage from low speed to high speed.Furthermore, a high speed capacitor charging coil with a small number of turns can be used as the capacitor charging coil, making it possible to use thicker wires. This has the excellent effect of not only preventing disconnection due to engine vibrations, but also reducing heat generation in the semiconductor switching element for cut-off control and the capacitor charging coil.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing a first embodiment of the device of the present invention, Fig. 2 is a bottom view showing the magnet generator in the first embodiment, and Fig. 3 is a diagram showing a second embodiment of the device of the present invention. electrical circuit diagram,
FIG. 4 is an electric circuit diagram showing the main part configuration of the third embodiment of the device of the present invention, FIG. 5 is an electric circuit diagram showing the detailed configuration of the rotation speed detection circuit used in each of the above embodiments, and FIG. FIG. 5 is a waveform chart of various parts for explaining the operation of the circuit shown in FIG. 1... Capacitor charging coil, 2.11... Timing sensor and ignition advance control circuit forming the ignition signal generation circuit, 4. 5. 21 to 23... Resistor constituting a detection circuit, 6.24... Transistor forming a semiconductor switching element for cut-off control, Cyrisk, 8... Transistor forming a semiconductor switching element for short circuiting, 9.
10... Rotation speed detection circuit and transistor constituting the rotation speed responsive conduction blocking circuit, 13... Capacitor, 16.
...Ignition coil, 16a, 16b...Primary, secondary coil, 17...Ignition plug.

Claims (1)

[Claims] A capacitor charging coil of a magnet generator, a shorting semiconductor switching element that substantially shorts one half-wave output of this charging coil, and a semiconductor switching element for cutoff control that shorts a control signal of this shorting semiconductor switching element. , a detection circuit for making the cut-off control semiconductor switching element conductive when a short-circuit current is sufficiently flowing through the short-circuit semiconductor switching element; and a high voltage induced in the charging coil when the short-circuit semiconductor switching element is cut off. an ignition coil having a primary coil and a secondary coil; and a rotational speed responsive conduction blocking circuit for blocking conduction of the shorting semiconductor switching element when the rotational speed of the internal combustion engine exceeds a predetermined value. an ignition signal generation circuit that generates an ignition signal at the ignition timing; and an ignition circuit that is electrically connected by the ignition signal from the ignition signal generation circuit to supply the charge charged in the capacitor to the primary coil of the ignition coil. a semiconductor switching element;
A non-contact ignition device for an internal combustion engine, comprising an ignition plug connected to a secondary coil of the ignition coil.