JP3538742B2 - Electric spark igniter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric spark igniter for igniting, for example, an even-cylinder gasoline engine.
In particular, the present invention relates to a drive circuit for the ignition coil.

[0002]

2. Description of the Related Art A conventional electric spark igniter for an even-cylinder gasoline engine for igniting two cylinders simultaneously has a power supply connected to one terminal of a primary winding of an ignition coil and a drive circuit for an ignition coil connected to the other terminal. Are connected to the secondary winding, and spark plugs are connected to both ends of the secondary winding. By controlling the current supplied to the primary winding of the ignition coil, a high voltage is generated in the secondary winding, and a spark is generated in the spark plug to ignite.

[0003]

However, in such an electric spark igniter, since only a current from one direction always flows through the ignition coil, one ignition plug has a positive voltage and the other has a positive voltage. Since only a negative voltage is applied to the spark plug and a better spark can be generated by applying the negative voltage, only the spark plug to which the negative voltage is applied can always satisfactorily ignite.

Therefore, it has been desired to realize an electric spark igniter capable of generating a good spark in both spark plugs.

[0005]

An electric spark igniter according to the present invention comprises a first switch, a second switch, and a third switch connected in series with the first switch. A fourth switch connected in series with the second switch, a connection point between the first switch and the third switch, and a connection between the second switch and the fourth switch. An ignition coil to which a primary winding is connected between the first switch means and an ignition coil;
Between the primary winding of the suspension coil and the second switch
Between the means and the primary winding of the ignition coil
Inserted with the ignition coil side as cathode
It has a diode and two sets of spark plugs connected to both ends of the secondary winding of the ignition coil. Then, the first switch means, the second switch means, the third
The switch means and the fourth switch means are
Consists Njisuta further first switch means and the fourth switching means, and a second switching means and the third switching means is closed alternately, a bidirectional current to the primary winding of the ignition coil The spark plug is supplied to generate a bidirectional electromotive force in the secondary winding, thereby generating sparks alternately in the two sets of spark plugs.

[0006]

FIG. 1 is a circuit diagram of an electric spark igniter according to an embodiment of the present invention. Reference numeral 1 denotes an ignition coil drive circuit (igniter), 2 denotes a power supply of a voltage VB, and 3 denotes an ignition coil. P1 and P2 are ignition plugs. One end of each of the ignition plugs P1 and P2 is connected to an ignition coil 3
Are connected to both ends on the secondary winding side. Each other end is grounded.

[0007] The ignition coil drive circuit 1 includes a transistor Q1, a transistor Q2, a transistor Q3 and a transistor Q4, and a diode D1 and a diode D2. The transistors Q1 and Q2 are PNP power transistors, and the transistors Q3 and Q4 are NPN power transistors. Transistor Q1, Transistor Q
2, the bases of the transistor Q3 and the transistor Q4 are connected to the input terminal IN1, the input terminal IN2, the input terminal IN3 and the input terminal IN4, respectively. The collectors of the transistors Q1 and Q2 are respectively connected to the anodes of the diodes D1 and D2. The collector of the transistor Q3 is connected to the cathode of the diode D1 and one end of the ignition coil 3 on the primary winding side.
The collector of the transistor Q4 is connected to another end of the transistor Q3 connected to the cathode of the diode D2 and the transistor Q3 on the primary winding side of the ignition coil 3. The emitters of the transistors Q1 and Q2 are connected to the power supply 2, respectively, and the emitters of the transistors Q3 and Q4 are grounded.

As described above, the transistors Q1, Q2, Q3, and Q4
Is connected in this way, and is generally called an H-bridge circuit used for forward and reverse rotation driving of the motor. This embodiment uses an H-bridge circuit to switch the current, and by adding a diode D1 and a diode D2, the transistors Q1 and Q2
And a large electromotive force is obtained in the ignition coil 3.

First, an input terminal IN1 and an input terminal IN4
Then, a control voltage for driving is applied to turn on the corresponding transistors Q1 and Q4. At this time,
Since no control voltage is applied to the input terminals IN2 and IN3, the transistors Q2 and Q3 are turned off.
This is the state of F. Transistor Q1 and transistor Q4
Is turned on, the transistors Q1 and Q4
, A collector current flows from the transistor Q1 to the transistor D4 through the diode D1 and the ignition coil 3. Transistor Q1
When the transistor Q4 is turned off slightly more quickly, the current flowing in the primary winding of the ignition coil 3 attempts to flow in the direction of the transistor Q2, but the diode D2 has such a current because the direction of the current is reverse. To stop the inflow. Therefore, since the current flowing through the primary winding of the ignition coil 3 changes rapidly, a negative high voltage is applied to the ignition plug P1 connected to the secondary winding of the ignition coil 3, and a positive high voltage is applied to the ignition plug P2. To generate sparks at the spark plugs P1 and P2.

Next, the input terminal IN2 and the input terminal IN3
Then, a control voltage for driving is applied to turn on the corresponding transistors Q2 and Q3. At this time,
Since no control voltage is applied to the input terminals IN1 and IN4, the transistors Q1 and Q4 are turned off.
This is the state of F. Transistor Q2 and transistor Q3
Is turned on, the transistors Q2 and Q3
, A collector current flows from the transistor Q2 to the transistor D3 through the diode D2 and the ignition coil 3. Transistor Q2
If the transistor Q3 is turned off slightly more quickly, the current flowing through the primary winding tries to flow in the direction of the transistor Q1, but the diode D1 prevents the current from flowing because the direction of the current is reversed. I do. Therefore, the current flowing through the primary winding changes abruptly, so that a high voltage in the opposite direction is generated in the secondary winding, and a negative high voltage is applied to the connected ignition plug P2 and a positive voltage is applied to the ignition plug P1. Is applied, and the spark plugs P1 and P2
Generates sparks.

By repeatedly turning on or off the transistors Q1 and Q4 and the transistors Q2 and Q3 as described above, a negative high voltage is alternately applied to the ignition plugs P1 and P2. Then, both spark plugs generate a good spark for ignition.

In order to prevent a current from flowing into the transistor Q1 or the transistor Q2 from the collector side, to prevent the transistor Q1 or the transistor Q2 from being destroyed, and to generate a large electromotive force by the ignition coil 3 at that time. , The diode D1 and the diode D2 have a breakdown voltage higher than the breakdown voltage between the collector and the emitter of the transistor Q3 and the transistor Q4.

In the electric spark ignition device configured as described above, the transistor Q1 and the transistor Q4,
When the transistor Q2 and the transistor Q3 are turned ON or OFF, the direction of the current flowing through the primary winding of the ignition coil 3 can be made bidirectional, and the direction of the electromotive force generated in the secondary winding can be made bidirectional. . In addition, the diodes D1 and D2 prevent the currents flowing into the collectors of the transistors Q1 and Q2, respectively, so that the transistors Q1 and Q2 are protected and the ignition coil 3
, A high electromotive force is generated in the secondary winding. For this reason, a negative high voltage is alternately applied to the ignition plugs P1 and P2, so that a good spark is generated in both ignition plugs and ignition can be obtained.

In the above embodiment, the ignition coil drive circuit using bipolar transistors has been described. However, the present invention is not limited to this.
The circuit may be configured by using a semiconductor switch such as.

In the above embodiment, the transistors Q3 and Q4 are turned off first, but the transistors Q1 and Q2 are
And the transistor Q4 may be turned off at the same time.

[0016]

As described above, according to the present invention, the current flowing through the primary winding of the ignition coil is controlled by the first switch means and the fourth switch means, and the second switch means and the third switch means. Since switching can be performed in both directions, the direction of the electromotive force generated in the secondary winding is bidirectional, so that good sparks can be generated in the two sets of spark plugs alternately for ignition. Become. Also,
By providing a diode, the first switch means and the
Prevents current from flowing into switch means 2
By doing so, the first switch means and the second switch
To protect the switch from
It can generate a strong electromotive force.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an electric spark ignition device according to an example of an embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of each unit in the circuit diagram of FIG.

[Explanation of symbols]

1 Ignition coil drive circuit (igniter) 2 Power supply 3 Ignition coil P1, P2 Spark plug Q1, Q2, Q3, Q4 transistors D1, D2 diode IN1, IN2, IN3, IN4 input terminals

Claims (1)

(57) [Claims] A first switch unit; a second switch unit; a third switch unit connected in series with the first switch unit; and a third switch unit connected in series with the second switch unit. A primary winding between a fourth switch, a connection point between the first switch and the third switch, and a connection between the second switch and the fourth switch. An ignition coil to which a wire is connected, the first switch means and the ignition coil;
Between the primary winding, the second switch means and the
The aforesaid inset is respectively provided between the ignition coil and the primary winding.
Die inserted with ignition coil side as cathode
An anode and two sets of spark plugs connected to both ends of a secondary winding of the ignition coil, wherein the first switch means, the second switch means,
The third switch means and the fourth switch means
The first switch means and the fourth switch means, and the second switch means and the third switch means are alternately closed, each of which is composed of a transistor. An electric spark igniter, characterized in that a current is supplied in both directions to generate a bidirectional electromotive force in a secondary winding, and a spark is generated alternately in the two sets of spark plugs.