JPS587827B2 - internal combustion engine ignition system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine ignition device that generates a high ignition voltage by controlling power supply to an ignition coil using an ignition signal.

A conventional device of this type is shown in FIG.

In the figure, 1 is a DC power source, 2 is a signal generator consisting of a signal generator that generates an ignition signal in synchronization with the rotation of the engine (not shown), 3 is a transistor that opens and closes in response to the signal from the signal generator 2; Reference numeral 4 denotes an ignition coil consisting of a primary coil 4a, a secondary coil 4b, and an iron core 4c connected in series with this transistor to the DC power supply 1.
and the secondary coil 4b are magnetically coupled via an iron core 4c.

A spark plug 5 is connected in series to the secondary coil 4b, and the primary coil 4a is connected in series to the transistor 8.

Now, the current of the primary coil 4a (hereinafter referred to as primary current) is I
1. If the current and voltage of the spark plug 5 are Ig and ■g, respectively, the magnetic flux in the iron core 4c is φ, and the number of turns of the primary coil 4a and secondary coil 4b is N1 and N2, respectively, the operating waveform is
It becomes as shown in Fig. 3.

In other words, in Fig. 2, the horizontal axis is the magnetomotive force N1, I1, I1
If we take the magnetic flux φ on the vertical axis, the i-ization curve of the iron core 4c becomes as shown in 6.

Next, the operations of these conventional devices will be explained.

In the time domain up to time t1 in FIG. 3, the transistor 3 is ONL and the primary current 1 is flowing through the primary coil 4a.

Because of the magnetomotive forces N1 and I1 caused by the primary current (1), the magnetization curve 6 shown in FIG. 2 exists at the point 6a.

Now, if the transistor 3 is turned off at time t1, the magnetomotive force N1, 1, which existed up to then, becomes zero, so the magnetization curve 6 reaches a point 6c.

That is, around time 11, the magnetic flux φ of the iron core 4c decreases by the amount of change Δφ.

Since the magnetic flux φ is also linked to the secondary coil 4b, if the time required for the primary current ■1 to be interrupted is Δt, the voltage V2 induced in the secondary coil 4b is expressed by the following equation. .

This secondary voltage (2) becomes as shown by the broken line in Fig. 3, and at time t2 halfway to its peak point, the ignition plug 5 is destroyed by discharge, and the ignition plug current Ig begins to flow, monotonically attenuating by time t3. During this period, the voltage between the electrodes of the spark plug 5 is maintained at a substantially constant voltage Va.

The spark energy supplied to the spark plug 5 from time t2 to time t3 corresponds to the energy Bc expressed by the shaded area in FIG. 2, and this energy Ec is the energy Ec of the iron core 4c. When the material and dimensions are fixed, it is proportional to the product of the magnetomotive force N1, ■1 and the magnetic flux change Δφ.

As described above, the spark energy supplied to the ignition plug 5 by the conventional device is determined only by the energy stored in the iron core 4c while the primary current I1 of the ignition coil 4 is energized, which causes greater energy to be emitted. This can be done by increasing the primary current (1) or by using a large-capacity iron core, but this method is extremely inefficient and uneconomical.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by alternately exciting the primary circuit of the ignition coil, it is possible to generate a very large spark energy by using a conventional ignition coil. The purpose is to provide a device that can achieve this goal.

In FIG. 4 showing an embodiment of the present invention, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and 15.
16 is a PNP transistor, 19 and 20 are NPN transistors, and transistors 15 and 19 are diode 11.
and the primary coil 4a are connected in series to the DC power supply 1, while the transistors 16 and 20 are connected in series to the DC power supply 1 together with the diode 12 and the primary coil 4a.

13 and 14 are resistors that connect the transistors 15 and 1, respectively.
6 are applied to the bases of the transistors 19 and 20, respectively.

21 is a resistor 18 connected to the base of the transistor 16.
The inverter 22 is connected via the inverter 2.
1 and the base input of the transistor 15 via a resistor 1.7, 25 a capacitor connected in parallel to the input of the transistor 22, and 26 an input from the signal generator 2. A rectangular wave generating circuit such as a monostable multi-channel circuit receives a signal and generates a rectangular wave voltage, and its output section is connected to the base input section of the transistor 22 via a parallel circuit of a resistor 23 and a diode 24.

A curve 27 shown in FIG. 5 is a magnetization curve of the iron core 4c of the ignition coil 4.

FIG. 6 shows voltage and current waveforms at various parts in FIG. 4.

In FIG. 4 configured as described above, in the time domain before time t1 shown in FIG. 6, that is, immediately before the ignition timing of the engine, the output voltage V
26 is a low potential (hereinafter referred to as L), so the transistor 22 is OFF, and the output voltage V22 is at a high potential (hereinafter referred to as H).

Then, transistors 15 and 19 are OFF,
Since the transistors 16 and 20 are turned on, a primary current ■1, that is, ■
16 is flowing.

The magnetization state of the iron core 4c at this time is point 27 in FIG.
It is in a.

Now, when the signal voltage Vs is generated from the signal generation circuit 2 at time t1 in FIG.
6, which causes transistor 22 to turn on rapidly.
Then, transistor 15 and transistor 19 are turned on, and transistor 16 .
20 is turned off.

When the primary current I16 is cut off by this, the iron core 4
The magnetization state of c is from point 27a to point 2 as shown in FIG.
7b, resulting in a magnetic flux change ΔX.

This △2 is the same as the conventional method described above.
The voltage 2 shown in the figure is generated.

Then, at time t2, when the spark plug 5 is destroyed by discharge, a secondary current 2 flows as shown in FIG.

On the other hand, at time t1, as described above, transistor 1
5 and 19 are turned on, the 6th
A primary current I15 having a waveform as shown in the figure begins to flow.

Since the direction in which this primary current I15 flows is opposite to the primary current I16 with respect to the primary coil 4a, the magnetization state of the iron core 4c shifts from point 27b to point 27c shown in FIG. 5.

This reverse excitation effect causes a magnetic flux change Δ2 in the iron core 4c, and voltages V1 and V2 shown in the following equations are induced in the primary coil 4a and secondary coil 4b, respectively.

Furthermore, if the primary current I15 increases as shown in the waveform shown in FIG. 6 and the iron core 4c is not saturated with magnetic flux, the primary coil induced voltage 1 is equal to the voltage E of the DC power supply 1, so the following equation holds. The following formula holds true from each of the above formulas.

The waveform of the secondary voltage 2 given by this equation shows a flat waveform as shown by the broken line in FIG. 6, and this height is designed to be higher than the arc discharge voltage drop Va of the ignition plug 5. Therefore, the energy possessed by this secondary voltage (2) is superimposed on the discharge of the secondary voltage (2) and causes a secondary current (2) to flow to the spark plug 5.
It flows as 2.

In other words, the secondary current ■2 disappears at time t3, but
The next current ■2 flows during the period when ■2>■a is maintained or during the period when the rectangular wave voltage ■ゎ is H.

Therefore, the above two secondary current components ■2, ■ are applied to the ignition plug 5.
As shown in FIG. 6, the composite current IN of 2 flows from time t3 to time t4, and the arc voltage drop Va continues to be maintained during that period.

Next, at time t4, when the rectangular wave voltage 26 becomes L, the input current to the transistor 22 does not become zero rapidly due to the delay caused by the delay circuit of the resistor 23 and the capacitor 25, but gradually decreases. Slowly turning OFF.

In addition, the primary currents I16 and I15 are slowly reversed as shown in FIG.

This means that the magnetization state in the iron core 4c gradually changes from point 27c to point 27a in FIG. The secondary voltages (2) and (2) generated are both small and do not cause any discharge to the spark plug 5, causing no problem.

As described above, the present invention provides means for cutting off the current in the ignition coil at the ignition timing of the engine, as in the conventional device, simultaneously energizing the ignition coil in the reverse direction, and gradually removing the reverse energization after a predetermined period of time. This has the effect that even greater energy can be applied to the ignition plug in addition to the energy that can be supplied to the ignition plug by the conventional device, and that no extra spark discharge is generated in the ignition plug at the end of the spark discharge.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of a conventional device, FIGS. 2 and 3 are operation diagrams for explaining the operation of the conventional device, FIG. 4 is an electric circuit diagram showing an embodiment of the present invention, and FIG. 6 are operational diagrams for explaining the operation of an embodiment of the present invention. In the figure, 1 is a DC power supply, 2 is a signal generator, 15, 16, 1
9, 20, 22 are transistors, 26 is a square wave generation circuit, 13, 14, 17.23 are resistors, 5 is a spark plug, 11,
12 and 24 are diodes, 25 is a capacitor, 4 is an ignition coil, 4a is a primary coil, and 4b is a secondary coil. Note that the same reference numerals in the drawings indicate corresponding parts.

Claims (1)

[Claims] 1 a signal generating means for generating an ignition signal in synchronization with the internal combustion engine; a square wave generating means for generating a rectangular wave voltage upon receiving the ignition signal; and 2 An ignition coil that induces a high voltage in the secondary coil, and an electronic disconnection means A that is connected in series with the primary coil of the ignition coil and that disconnects the primary current flowing from the DC power source from one of the primary coils. electronic intermittent means B connected in series with the primary coil to intermittent the primary current flowing from the other primary coil; and alternately controlling the electronic intermittent means in accordance with the rectangular wave voltage output. An internal combustion engine characterized by comprising a control means and a delay means connected between the control means and the rectangular wave generating means and slowing down only one side of the change in the output voltage of the rectangular wave generating means. Engine ignition system.