JPH05340330A - Ignition control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an ignition control device for an internal combustion engine at a low cost without using an extra high voltage diode further with a circuit constitution simple and possible to surely prevent preignition. CONSTITUTION:In an ignition control circuit 2 of providing a primary current limiting transistor 6 and Zener diode 5, a base current control circuit 13, comprising a capacitor 14, diode 15 and a resistor 16, is provided, and by slowing a riseup of base voltage of a transistor 7 when an ignition signal rises up, a primary current in an ignition coil is slowed to rising, so as to suppress generation of high voltage in a secondary side at this time. Thus without increasing a number of connecting wires from the ignition control circuit 2, an ignition system, which can surely prevent preignition, can be provided at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine, which uses a transistor for controlling the conduction and interruption of the primary current of an ignition coil, and more particularly to an electronic power distribution system having an ignition coil independently for each spark plug. The present invention relates to an ignition control device suitable for an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine of an electric ignition system such as a gasoline engine, a current supplied to a primary coil of an ignition coil is interrupted at an ignition timing so that ignition is performed by a high voltage generated in the secondary coil. However, at this time, it is natural from the viewpoint of the function of the ignition coil, but even at the timing when the power supply to the primary coil is started, the polarity is opposite to the high voltage generated at the ignition timing, and it is quite high voltage. Is generated in the secondary coil.

By the way, even if a high voltage is generated at the start of energization, in an ignition device using a distributor, it does not cause much problem, but an electronic distribution system having an ignition coil independently for each spark plug. In the ignition system of
This causes the problem of pre-ignition.

Therefore, conventionally, as shown in FIG. 2, an extra-high voltage diode 10 is connected in series with an ignition plug 11 on the secondary side of an ignition coil 9 to prevent a high voltage generated at the start of energization. To prevent pre-ignition. In the conventional example of the ignition device of FIG. 2, 1 is an ECU
(Engine control unit) 2 is an ignition control circuit, 3 and 4 are resistors and capacitors forming a noise suppressing filter, 5 and 6 are zener diodes and transistors forming a constant voltage source for limiting the ignition current, Reference numeral 7 is a power transistor for controlling the interruption of ignition current, 8 is a resistor for detecting an ignition current, and 12 is a battery serving as a power source.

The ECU 1 generates a rectangular wave-shaped ignition signal that rises at a predetermined energization start timing before the ignition timing and falls at the ignition timing, and supplies it to the transistor 7 in the ignition control circuit 2 to supply the ignition coil 9. Controls the interruption of the primary current. The current flowing through the primary coil of the ignition coil 9 is converted into a voltage by the resistor 8 and supplied to the collector of the transistor 6, but the base of the transistor 6 is held at a constant voltage by the Zener diode 5. As a result, the base-emitter voltage of the transistor 6 becomes equal to the Zener voltage of the Zener diode 5, and the primary current of the ignition coil 9 is limited to a predetermined value.

FIG. 11 shows operation waveforms in this conventional ignition device. (A) is an ignition signal from the ECU,
(B) shows the primary current of the ignition coil, and (C) shows the secondary voltage waveform of the ignition coil. First, the rapid rise of the base voltage by the ignition signal of (A) causes the primary current of (B) to rise. The portion has an oscillating waveform, as indicated by d. As a result, in the secondary voltage of (C), an oscillation waveform appears on the positive pole side as shown by e.

Then, the voltage in the portion e of the secondary voltage of (C) becomes about 2 to 3 kV. Therefore, if it is left as it is, spark discharge occurs in the spark plug 11, and as a result, the normal ignition is performed. Ignition occurs before the timing, causing premature ignition. Therefore, an ultra-high voltage diode 10 is inserted on the secondary side of the ignition coil 9 to prevent the voltage of the positive polarity at the portion e of the secondary voltage of (C) so that premature ignition does not occur. Of.

On the other hand, for example, in Japanese Utility Model Publication No. 58-7099, in order to prevent the high voltage generated at the start of energization, the power transistor for controlling the primary current of the ignition coil is turned on until it is turned on. An ignition device with a feedback circuit that delays the fall time is disclosed.

[0009]

The above-mentioned prior art requires an ultra-high voltage diode to prevent premature ignition, and
There is no consideration for complication of the circuit configuration when applying the premature ignition prevention function to the electronic distribution type ignition device, the cost is likely to increase, and the problem that the practical system configuration is difficult there were.

More specifically, among the above-mentioned prior arts, the prior art disclosed in Japanese Utility Model Publication No. 58-7099 describes only the configuration of the feedback circuit, and the points that should be aimed at preventing premature ignition are described. I have not disclosed anything. Further, in this conventional technique, a feedback circuit is configured by connecting a series circuit of a capacitor and a diode between the base and collector of the power transistor and a resistor between the connection point of the capacitor and the diode and the power supply. As a result, the feedback circuit requires a power source, and the circuit is required to be formed between the collector and the base of the power transistor, which makes connection difficult. Especially, in an internal combustion engine ignition device for an electronic power distribution system, an engine cylinder is difficult to connect. The number of drive circuits increases according to the number, but at this time, in this conventional technique, a feedback circuit is required for each drive circuit, and the configuration becomes complicated.

An object of the present invention is to provide an ignition control device for an internal combustion engine, which has a simple structure and is not likely to increase the cost, and which can be easily applied to an electronic distribution type ignition device at a low cost. ..

[0012]

SUMMARY OF THE INVENTION The above-described object is to provide a circuit means including a capacitor in a base circuit of a power transistor for controlling energization / interruption of a primary side current of an ignition coil, and a capacitor for suppressing a steep rise of the base voltage. Is provided and the current on the primary side of the ignition coil is smoothly started.

[0013]

According to the present invention, the HIG of the ignition signal (driving signal) is
When H is input, the capacitor connected to the base of the power transistor is charged,
This drive signal causes an arbitrary predetermined delay time. As a result, the rise of the primary current of the ignition coil is smoothed, so that a positive high voltage generated on the secondary side of the ignition coil at the start of energization is suppressed and premature ignition can be prevented.

On the other hand, when the ignition signal changes from HIGH to LOW, the electric charge charged in the capacitor is discharged. However, if the electric charge flows into the base side of the power transistor, the cutoff of the primary current is delayed, so that the diode and the resistor are disconnected. The series circuit is used to discharge to the emitter of the power transistor or GND.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ignition control device for an internal combustion engine according to the present invention will be described in detail below with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention in which an ECU 1, an ignition control circuit 2, a resistor 3, a capacitor 4, a zener diode 5, a transistor 6, a power transistor 7, a current detecting resistor 8, an ignition coil 9, an ignition plug 11 and The battery 12 is the same as the conventional example described with reference to FIG. 2, and the point that the embodiment of FIG. 1 differs from the conventional example described with reference to FIG. 2 is that the ultra high voltage diode 10 in the conventional example is excluded. On the other hand, the base current control circuit 13 is provided in the ignition control circuit 2.

The base current control circuit 13 is composed of a capacitor 14 connected in parallel with the Zener diode 5, and a series connection circuit of a diode 15 and a resistor 16 which are also connected in parallel. First, the capacitor 14 is connected to the ECU.
1 is charged by the voltage applied to the Zener diode 5 between the emitter and the base of the PNP transistor 6 at the rising of the ignition signal supplied from No. 1, and the terminal voltage of the Zener diode 5 at this time is moderated Then, the series circuit of the diode 15 and the resistor 16 functions to discharge the electric charge accumulated in the capacitor 14 with a predetermined time constant.

Next, the operation of this embodiment will be described. The base input signal (ignition signal) from the ECU 1 is LOW
When it goes from HIGH to HIGH, the current due to this goes from the emitter of the PNP transistor 6 through the base to the capacitor 1
Charged to 4. As a result, the rise of the primary current of the ignition coil 9 becomes gentle, and the generation of the positive polarity secondary voltage at this time is suppressed. Further, the electric charge thus charged in the capacitor 14 is discharged to the ground through the diode 15 and the resistor 16.

FIG. 12 shows the operation waveforms in the embodiment of FIG. 1. As in the case of the prior art of FIG. 11, (A) is the ignition signal from the ECU 1 and (B) is the ignition coil. The primary current, (C) shows the secondary voltage waveform of the ignition coil. As is apparent from FIG. 12, in this embodiment, the base current control circuit 13 is provided in the ignition control circuit 2, so that as shown in FIG. The current change becomes smooth, and as a result, as shown in FIG. 11C, the oscillation of the positive polarity at the portion e of the secondary voltage disappears, and as a result, the base current control as in the conventional example shown in FIG. Compared with the case where the circuit 13 is not provided, the generated voltage value of the positive polarity is reduced by about 30%.

Therefore, according to this embodiment, the change in the current at the rising portion d of the primary current becomes smooth, and as a result, as shown in FIG. 7C, the plus at the portion e of the secondary voltage. Polarity oscillation is also eliminated, and pre-ignition can be prevented without providing an ultra-high voltage diode on the secondary side of the ignition coil 9. Further, according to this embodiment, the ignition control circuit 2
The connection line from the outside to. Since only the path for the ignition signal from the ECU 1 and the path for the primary coil of the ignition coil 9 are required, there is no fear that the number of connecting wires will increase even when applied to an electronic distribution type ignition device, and the circuit configuration is It will be easy.

Next, another embodiment of the present invention will be described. First, in the embodiment shown in FIG. 3, the resistor 16 in the base current control circuit 13 is connected to the emitter of the power transistor 7 so that the electric charge of the capacitor 14 is discharged. It is similar to the embodiment. Next, FIG. 4 is also an embodiment of the present invention, in which the capacitor 14 in the base current control circuit 13 is inserted between the base and collector of the PNP transistor 6, which also has the same operational effect as in FIG. It is similar to the embodiment.

FIG. 5 is also an embodiment of the present invention. In this embodiment, the base current control circuit 13 is provided in the internal combustion engine ignition device using the NPN transistor 18 as a transistor in the ignition control circuit 2 to premature ignition. The capacitor 18 has a diode 18 connected in series and is inserted between the collector and the emitter of the NPN transistor 18.

Next, FIG. 6 shows the four cylinders based on the two cylinder simultaneous ignition system.
An example of an embodiment in which the present invention is applied to an electronic power distribution system of a cylinder engine is shown.
The current control resistor 8 and the base current control circuit 13 are commonly provided for the system ignition control circuit. This base current control circuit 13 is basically the same as that of the embodiment of FIG. 1, so a detailed description thereof will be omitted, but according to this embodiment, the circuit configuration can be greatly simplified and a sufficient cost reduction can be achieved. be able to.

Next, FIGS. 7 and 8 show an embodiment in which the present invention is applied to an independent ignition type electronic power distribution system for four cylinders. First, the embodiment of FIG. a
8D, one resistor 8 for current detection and one base current control circuit 13 are commonly provided for each of FIG.
Is a system in which four systems of ignition systems a to d are divided into two groups of two systems, and each group is provided with resistors 8a and 8c for current detection and base current control circuits 13a and 13c, respectively.

9 and 10 show an embodiment in which the present invention is applied to an independent ignition type electronic power distribution system for 6 cylinders. First, the embodiment of FIG.
10 to f are commonly provided with one resistor 8 for current detection and one base current control circuit 13.
In the embodiment of the present invention, the six ignition systems a to f are divided into two groups of three systems, and each group has a resistor 8a for current detection,
8d and base current control circuits 13a and 13d are provided.

Therefore, according to the embodiments shown in FIGS. 7 to 10, there is an effect that a large cost reduction can be obtained by sharing the circuit. Incidentally, not limited to these examples,
Even when the number of cylinders of the internal combustion engine ignition device is increased, the same control can be performed according to the present invention, and the sharing of the base current control circuit is arbitrarily applied to one ignition system to a plurality of ignition systems. It is possible.

[0026]

According to the present invention, it is possible to suppress the secondary voltage on the positive side generated at the start of energization of the primary current of the ignition coil without using an ultrahigh voltage diode for preventing premature ignition. An ignition system for an internal combustion engine can be provided at low cost. Further, according to the present invention, it becomes possible to prevent premature ignition by the base current control method,
Compared with the feedback circuit according to the conventional example, the objective can be achieved with an inexpensive and simple circuit, and a power supply connection line for the base current control circuit is not required. Therefore, an ignition system having a plurality of ignition coil drive circuits is provided at low cost. There is an effect that you can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an ignition control device for an internal combustion engine according to the present invention.

FIG. 2 is a circuit diagram showing a conventional example of an ignition control device for an internal combustion engine.

FIG. 3 is a circuit diagram showing another embodiment of the present invention.

FIG. 4 is a circuit diagram showing another embodiment of the present invention.

FIG. 5 is a circuit diagram showing another embodiment of the present invention.

FIG. 6 is a circuit diagram showing another embodiment of the present invention.

FIG. 7 is a circuit diagram showing another embodiment of the present invention.

FIG. 8 is a circuit diagram showing another embodiment of the present invention.

FIG. 9 is a circuit diagram showing another embodiment of the present invention.

FIG. 10 is a circuit diagram showing another embodiment of the present invention.

FIG. 11 is a waveform diagram for explaining the operation of the conventional example.

FIG. 12 is a waveform diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

1 Engine Control Unit (ECU) 2 Ignition Control Circuit 3 Resistor for Noise Filter 4 Capacitor for Noise Filter 5 Zener Diode Constituting Constant Voltage Source for Ignition Current Limit 6 PNP Constituting Constant Voltage Source for Ignition Current Limit Transistor 7 Power transistor for controlling the interruption of ignition current 8 Resistance for current detection 9 Ignition coil 11 Spark plug 12 Battery 13 Base current control circuit 14 Capacitor 15 for slowing the rise of voltage 15 Discharges electric charge with a predetermined time constant Diode 16 Resistance for discharging electric charge with a predetermined time constant 17 Diode 18 NPN transistor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noboru Sugiura 2520 Takaba, Takata, Ibaraki Prefecture, Hitachi Automotive Systems Division (72) Inventor Ryoichi Kobayashi 2520, Takaba, Katsuta, Ibaraki Hitachi, Ltd. Factory Automotive Equipment Division

Claims (5)

[Claims] 1. An internal combustion engine, comprising: a transistor for controlling energization and interruption of a primary current of an ignition coil according to an ignition signal; and a current limiting transistor for controlling a base voltage of the transistor according to a detection result of the primary current. In the ignition device, a current rising suppression circuit including a capacitor connected between the base of the current limiting transistor and the ground and a series connection circuit of a diode and a resistor connected in parallel with the capacitor is provided to start energization of the primary current. An ignition control device for an internal combustion engine, wherein the ignition control device is configured to suppress generation of a secondary voltage depending on time. 2. An internal combustion engine, comprising: a transistor for controlling energization and interruption of a primary current of an ignition coil according to an ignition signal; and a current limiting transistor for controlling a base voltage of the transistor according to a detection result of the primary current. In the ignition device, a current rise suppression circuit is provided that includes a capacitor connected between the base and the emitter of the current limiting transistor, and a series connection circuit including a diode and a resistor connected in parallel with the capacitor, and supplies the primary current. An ignition control device for an internal combustion engine, which is configured to suppress generation of a secondary voltage at the time of starting. 3. An internal combustion engine comprising a transistor for controlling energization and interruption of a primary current of an ignition coil according to an ignition signal, and a current limiting transistor for controlling a base voltage of the transistor according to a detection result of the primary current. In the ignition device, a current rising suppressing circuit including a series connection circuit of a diode and a capacitor connected between the base and the emitter of the current limiting transistor and a series connection circuit of a diode and a resistor connected in parallel with the capacitor is provided. An ignition control device for an internal combustion engine, wherein the ignition control device is configured to suppress generation of a secondary voltage at the start of energization of the primary current. 4. The invention according to any one of claims 1 to 3,
An internal combustion engine, wherein the internal combustion engine is a multi-cylinder internal combustion engine including two or more cylinders, and the current rising suppression circuit is provided in common for at least two ignition coils of each cylinder. Ignition control device. 5. The ignition control device for an internal combustion engine according to claim 4, wherein the multi-cylinder internal combustion engine is an electronic distribution type internal combustion engine having an ignition coil independently for each spark plug. ..