JPH0631598B2 - Capacity discharge type internal combustion engine ignition device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition device for an internal combustion engine, and more particularly to improvement of a capacity discharge ignition device.

[Prior Art] There are typically two types of ignition devices for internal combustion engines, a current interrupt type and a capacitive discharge type, and a combined type thereof, but the capacity to be improved in the present invention The discharge type ignition device has a circuit structure classically or basically as shown in FIG.

Since it is well known, a brief description will be given. A DC-DC converter or the like for boosting the voltage across a vehicle-mounted battery (not shown),
A suitable high-voltage generating circuit 11 has accumulated sufficient electric charge in the energy storage capacitor 12 in advance, and in that state, the ignition timing of the corresponding cylinder is reached, and the timing for discharging a discharge spark to the discharge gap (ignition plug) 17 is. When it comes, an appropriate ignition timing signal generating circuit (not shown) outputs the ignition timing signal or the trigger signal Sg, whereby the switching element 16 shown as a thyristor is turned on.

Then, the stored charge of the energy storage capacitor 12, which has stored and waited for the charge, flows as a primary current i _c from the primary winding 13 of the ignition coil 15 through the thyristor 16 that is turned on, and due to its abrupt rise. , Generates an induced high voltage in the secondary winding 14 of the ignition coil 15, and discharges sparks to the corresponding spark plug 17.

The diode 18 connected in parallel to the energy storage capacitor 12 but in the reverse direction with respect to the charging current from the high voltage generation circuit 11 is for preventing the reverse charging of the capacitor 12.

As is clear to some extent from such a mechanism, since the discharge mechanism of the capacitive discharge ignition device depends on the instantaneous discharge of the electric charge accumulated in the capacitor, it has a basic circuit configuration as shown in FIG. Also, there is a feature that a spark with a quick rise can be obtained.

However, similarly, as understood from the above discharge mechanism, the discharge connection time is long and difficult.

Therefore, conventionally, an improvement plan as shown in FIG. 4 has been proposed. In the figure, the same reference numerals are circuit elements that do not need to be changed to the elements in the third illustrated circuit, and the above description can be applied to them as they are.
The component added in the illustrated improvement is an inductor 19 inserted in series in the discharge path of the energy storage capacitor 12.

As is apparent, according to such a configuration, the amount of electric charge to be discharged from the energy storage capacitor 12 through the ignition coil primary winding 13 is limited by the presence of the inductor 19 in the unit time, As a result, the discharge duration is longer than in the ignition circuit of the third illustrated configuration without the inductor 19.

[Problems to be Solved by the Invention] As described above, according to the circuit configuration shown in FIG. 4 presented as an improvement plan of the basic capacity discharge type ignition device shown in FIG. 3, the drawbacks of the capacity discharge type ignition device are shown. It was possible to compensate for the short discharge duration, which was supposed to be.

However, the presence of the inductor 19 naturally slows down the initial discharge rate of the charge stored in the energy storage capacitor 12.

That is, as the value of the inductor is increased to increase the discharge duration, the discharge rising characteristic, which is the original feature of the capacitive discharge ignition device, is sacrificed. There was.

The present invention was made in order to further improve this point.

That is, the present invention aims to provide a circuit configuration capable of extending the discharge duration while maintaining the advantage of the discharge having a fast rise inherently possessed by the capacity discharge ignition device or without impairing it as much as possible.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a parallel arrangement of an inductor and a capacitor in a discharge path when the charge stored in the energy storage capacitor is discharged through the ignition coil primary winding. We propose a configuration in which the circuit is inserted in series.

[Operation] In the capacitive discharge ignition device of the present invention, the primary winding of the ignition coil is included in series, and the inductor and the capacitor are provided in series in parallel with respect to the discharge path through which the accumulated charge of the energy storage capacitor is discharged. In the circuit, the capacitor allows the electric charge to be discharged quickly at the time of starting the discharge by the differential operation, so that the spark spark having a fast rising can be blown to the ignition plug connected to the secondary winding of the ignition coil.

On the other hand, the inductor in the parallel circuit of the inductor and the capacitor extends the duration of the discharge spark obtained in the spark plug as a result by narrowing down the amount of discharge current started immediately as described above by the integral operation. Contribute to letting.

[Embodiment] FIG. 1 shows a preferred embodiment of a capacity discharge ignition device constructed according to the present invention.

However, in comparison with the above-described conventional examples shown in FIGS. 3 and 4, the corresponding components or components that do not particularly require modification are shown in this figure and in FIG. 2 showing a second embodiment described later. Also, description will be given with the reference numerals used in FIGS.

Also in this embodiment, there is a suitable high-voltage generating circuit 11 such as a DC-DC converter for boosting the voltage across the battery mounted on the vehicle (not shown), which has accumulated sufficient electric charge in the energy storage capacitor 12 in advance. In that state, when the ignition timing of the cylinder provided with the illustrated spark plug 17 is reached, the appropriate ignition timing signal or trigger signal Sg is output from an appropriate ignition timing signal generation circuit (not shown), and this is indicated as a thyristor. The switching element 16 being turned on is turned on.

Then, the stored charge of the energy storage capacitor 12, which has stored and waited for the charge, flows as a coil primary current i _{c in the} discharge path from the primary winding 13 of the ignition coil 15 through the thyristor 16 which is turned on. Allows the ignition coil 15
An induced high voltage is generated in the secondary winding (14), and a spark is discharged to the corresponding spark plug (17). Energy storage capacitor 12
The diode 18, which is connected in parallel with, but in the reverse direction with respect to the charging current from the high voltage generation circuit 11, is for preventing the reverse charging of the capacitor 12, as also described above.

In the case of the present invention, however, the above-mentioned discharge path, that is, the hot side end of the energy storage capacitor 12 is connected to the ignition coil.
A parallel circuit of an inductor 19 and a capacitor 20 is inserted in series in a path returning to the other end of the energy storage capacitor through the primary winding 13 of 15 and the switching element 16.

Therefore, the capacitor 20 in the LC parallel circuit can steeply discharge the electric charge from the energy storage capacitor 12 by its differentiating operation, and secures a fast rising discharge characteristic which is the original feature of the capacitive discharge ignition device. While doing
The inductor 19 prolongs the discharge started by reducing the flow rate of the discharge charge by its integrating operation, and thus compensates for the short discharge duration which has been a drawback of the capacitive discharge ignition device. Needless to say, the closer the inductor 19 is to a pure inductor, that is, the lower the resistance component, the better.

As described above, the ignition device shown in FIG. 1 can compensate only the drawbacks while maintaining the advantages of the capacity discharge ignition device. However, when the ignition device is actually applied to the internal combustion engine ignition device of a plurality of cylinders, The high voltage generation circuit 11, the energy storage capacitor 12, and the parallel circuit of the inductor 19 and the capacitor 20 added by the present invention can be common to all the ignition coils for the cylinders.

FIG. 2 shows the concept of such a case. In the case of the drawing, a total of four ignition coils 15, one for each cylinder for a four-cylinder vehicle are shown.

The primary windings 13, ... Of the respective ignition coils 15, ... Are commonly connected to one end of the parallel circuit of the inductor 19 and the capacitor 20 provided by the present invention. The other end of is connected to one end of a single, common energy storage capacitor 12, to which the output of a single high voltage generating circuit 11 is applied.

However, as a matter of course, each ignition coil 15, ...
Since the ignition timing signal Sg generated at each ignition timing is selectively driven according to each ignition timing,
Are individually applied to the switching elements 16, ....

Such a configuration concept can be similarly adopted even if the cylinder is changed, and the thyristor exemplified as the switching element 16 can be used as a bipolar power transistor, a field effect transistor, or the like in any of the first and second embodiments. , Other suitable switching elements can be substituted.

[Effect] As described above, according to the present invention, the parallel circuit of the inductor and the capacitor is inserted in series in the discharge path including the primary winding of the ignition coil, so that the capacitor secures the rising speed of the discharge spark. However, since the discharge duration can be lengthened by the inductor, it is possible to compensate for the short discharge duration, which was a drawback, while keeping the advantages of the conventional capacitive discharge ignition device almost as it is. It will be one of the most desirable.

Moreover, even though the useful effects are obtained as described above, the necessary circuit configuration is simple, and the newly required parts are very easily available and only inexpensive inductors and capacitors are necessary. , In that sense is also excellent.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of a capacity discharge ignition device configured according to the present invention, and FIG. 2 is a schematic configuration diagram of a desirable one configuration example when the present invention is applied to a plurality of ignition coil systems, FIG. 4 is an explanatory diagram of the basic components of the capacity discharge ignition device, and FIG. 4 is a schematic configuration diagram of an improvement made to the conventional capacity discharge ignition device. In the figure, 11 is a high-voltage generating circuit, 12 is an energy storage capacitor, 13 is an ignition coil primary winding, 14 is a secondary winding, 15 is an ignition coil as a whole, 16 is a switching element, 17 is an ignition plug, and 19 is an ignition plug. Is an inductor and 20 is a capacitor.

Claims (1)

[Claims] 1. When the ignition timing is reached, the charge previously stored in the energy storage capacitor is discharged through a discharge path, and the discharge charge is supplied to an ignition coil primary winding included in series in the discharge path. Is a capacity discharge type internal combustion engine ignition device that generates a high voltage on the secondary winding side thereof and discharges sparks to an ignition plug connected to the secondary winding side; discharge path of the energy storage capacitor An inductor for extending the discharge time of the charge from the energy storage capacitor is inserted in series therein; and in parallel with the inductor, the rise of the discharge start of the charge from the energy storage capacitor is made steep. A capacitor discharge type internal combustion engine ignition device, characterized in that a capacitor is connected.