JPH04148066A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to realize a compact size of the device by composing to provide a set of a rectifier element, a capacitor, and an inductor, commonly to high voltage generating circuits, corresponding to cylinders of an engine. CONSTITUTION:To each circuit of high voltage generating circuits 171 to 17n provided at the output side of a DC-DC converter 2 which boosts the DC voltage of a battery 1 to several hundreds voltage corresponding to the number of cylinders, an ignition coil 6, an ignition plug 7, a switching element 8, a diode 12, and a switching element 16 for extending the discharge keeping up time are built in. And at the outer side of these high voltage generating circuits 171 to 17n, a set of diodes 4 and 15 for rectifying, capacitors 5 and 9, and an inductor 10, is provided. And in the ignition time of the engine, one of the high voltage generating circuits 171 to 17n corresponding to the cylinder is energized, and the ignition plug 7 is ignited through the ignition coil 6, by turning on the switching element 8 by the trigger signal from a trigger circuit 14 according to the ignition signal generated from an ignition signal generating circuit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ignition device for an internal combustion engine, and particularly to a low-voltage power distribution capacitor discharge type ignition device for an internal combustion engine with an extended discharge duration.

[Prior Art] Fig. 3 is a block diagram showing a conventional low-voltage power distribution type capacitor discharge type ignition system for an internal combustion engine with an extended discharge duration. DC-DC converters connected to (1) and boosting the DC voltage of battery (1) to several hundred volts, (31) to (
3, , ) are high pressure generation circuits provided on the output side of the DC-DC converter (2) corresponding to the number of cylinders. High voltage generation circuits (31) to (3o) are DC-DC converters (2
), a rectifier diode (4) provided on the output side of the diode (4), a capacitor (5) connected to this diode (4), and an ignition coil (6
), a spark plug (7) provided on the secondary side of this ignition coil (6), a switching element (8) connected between the cathode side of the diode (4) and the ground, and a diode (4).
A capacitor (9) is connected in series to the cathode side of the ignition coil (6) and the primary side of the ignition coil (6), and an inductor (10) for extending the discharge duration is connected between one end of the inductor (10) and the ground. and a vibration prevention diode (12) connected between the other end of the inductor (10) and the ground. (13) is an ignition signal generation circuit connected to the battery (1) and generates an ignition signal in synchronization with the rotation of the internal combustion engine; (14) is connected to the battery (1) and the ignition signal generation circuit (13); A trigger circuit that generates a trigger signal in response to an ignition signal.

Next, the operation of the conventional ignition system for an internal combustion engine shown in FIG. 3 will be explained. The DC-DC converter (2) is driven by a drive pulse from an oscillation circuit (not shown),
The DC voltage of the battery (1) is boosted to several hundred volts, and the capacitor (5) is charged through the diode (4). The charges charged in the capacitors (5) and (9) are
The ignition signal oscillation circuit (
The trigger circuit (13) responds to the ignition signal generated from the
For example, the trigger signal from 4) causes the switching element (8) of the high voltage generation circuit (3,
) primary side → capacitor (5) and capacitor (9) →
Switching element (8) → Primary side of ignition coil (6) →
Discharge occurs in each path from the inductor (10) to the capacitor (9). This generates a high voltage on the secondary side of the ignition coil (6), causing the ignition plug (7) to ignite.

Here, a current flows through the path of the inductor (10) → diode (11) → the primary side of the ignition coil (6) → the inductor (10). This increases the duration of the discharge at the spark plug (7). This type is called LCD
It is called type I.

Further, at another ignition timing of the engine, the high pressure generation circuit corresponding to that cylinder is energized, and ignition is performed in the same manner as described above.

[Problems to be Solved by the Invention] Since the conventional ignition device for an internal combustion engine is configured as described above, the number of diodes (4) equal to the number of cylinders of the engine,
Since the capacitors (5), (9) and the inductor (10) are required, the number of parts increases, the configuration becomes complicated, and the device becomes large.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain an ignition device for an internal combustion engine that is simple in structure and small in size.

[Means for Solving the Problems] An ignition device for an internal combustion engine according to the present invention includes first and second rectifying elements that rectify a boosted DC power supply voltage, and a second rectifying element that is charged by the output of the rectifying element. The first and second capacitors, an inductor for extending the discharge duration provided in the discharge path of the second capacitor, and one set of the rectifying element, the capacitor, and the inductor are arranged so as to correspond to each cylinder of the engine. and a high voltage generation circuit provided with an ignition coil, a first switching element that forms a discharge path for the capacitor through the ignition coil, and a current path through the inductor and the ignition coil. A second switching element is formed, and a third rectifying element is connected to the primary side of the ignition coil.

[Operation] In the present invention, the high pressure generation circuits provided corresponding to each cylinder of the engine share one set of a rectifying element, a capacitor, and an inductor.

Then, the charge in the capacitor is discharged through each high voltage generation circuit according to the ignition timing, and the ignition plug is ignited.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a configuration diagram showing one embodiment of the present invention, (1),
(2), (4) to (10 m) (12) to (14) are the same as described above. In this embodiment, the high voltage generation circuit (
17,) to (17,) include an ignition coil (6), a spark plug (7), a switching element (8), and a diode (12).
and a switching element (16) for extending the discharge duration. Rectifying diodes (4), (15) and capacitors (5) (9) are installed outside these high voltage generation circuits.
and an inductor (10).

A diode (4) is connected between the DC-DC converter (2) and the ground.
) and a series circuit of a capacitor (5) and a diode (15
) and a series circuit of a capacitor (9) are provided in parallel. A connection point between the diode (4) and the capacitor (5) is grounded via the primary side of the ignition coil (6) and the switching element (8). Diode (15) and capacitor (9)
Connect the connection points of the inductor (10) and the ignition coil (6) to 1.
Grounded via the next side and the switching element (8).

A diode (12) is connected in parallel to the primary side of the ignition coil (6), and the connection point between the diode (15) and the capacitor (9) and the connection point between the primary side of the ignition coil (6) and the switching element (8). A switching element (16) is connected to.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be explained with reference to FIG. 2. The DC-DC converter (2) is driven by drive pulses from an oscillator circuit (not shown) to boost the DC voltage of the battery (1) to several hundred volts, and boosts the DC voltage of the battery (1) to several hundred volts through the diodes (4) and (15), respectively to the capacitor (5). ), (9). Capacitor (5
), (9) are activated by a trigger circuit (1) in response to an ignition signal as shown in FIG.
The trigger signal from 4) as shown in the second diagram makes the switching element (8) of the high voltage generation circuit (17,) conductive, so that the capacitor (5) → the ignition coil (6)
Primary side → switching element (8) → capacitor (5)
Then, the discharge occurs along the respective paths from the capacitor (9) to the inductor (10) to the primary side of the ignition coil (6) to the switching element (8) to the capacitor (9) as shown in FIGS. 2E and F. As a result, the secondary side of the ignition coil (6)
A high voltage as shown in Figure G is generated and a high current as shown in Figure 2H is generated, causing the spark plug (7) to ignite. On the other hand, the switching element (16) is made conductive by the trigger signal as shown in FIG.
A current flows in the path of the inductor (10). This increases the duration of the discharge at the spark plug (7).

Further, at another ignition timing of the engine, the high pressure generation circuit corresponding to that cylinder is energized, and ignition is performed in the same manner as described above. That is, for example, a trigger signal (not shown) corresponding to the ignition signal as shown in FIG. A high voltage as shown in Figure 2 I is generated on the side, and a high current as shown in Figure 2 J is generated.
The spark plug (7) ignites. Of course, at this time, the switching element (16) in the high voltage generating circuit (172) becomes conductive and the discharge duration is extended, as described above.

In this way, in this embodiment, the high pressure generation circuit (17,
) to (17,), the diodes (4), (15),
Capacitors (5), (9) and inductor (10) are 1
Refining is simplified because only one piece is required.

[Effects of the Invention] As described above, according to the present invention, the first and second rectifiers that rectify the boosted direct-fi power supply voltage, and the first and second rectifiers that are charged by the outputs of the rectifiers, respectively, are provided. a capacitor, an inductor for extending the discharge duration provided in the discharge path of the second capacitor, and a rectifier provided corresponding to each cylinder of the engine so as to share one set of the capacitor and inductor. a high voltage generation circuit, the high voltage generation circuit includes an ignition coil, a first switching element that forms a discharge path for the capacitor through the ignition coil, and a second switching element that forms a current path through the inductor and the ignition coil. Since the present invention includes a switching element and a third rectifying element connected to the primary side of the ignition coil, an ignition device for an internal combustion engine with a reduced number of parts and a smaller device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a waveform diagram for explaining the operation of the diagram, and FIG. 3 is a configuration diagram showing a conventional ignition device for an internal combustion engine. In the figure, (2) is a DC-DC converter, (4),
(12) and (15) are diodes, (5) and (9) are capacitors, (6) are ignition coils, (8) and (16) are switching elements, (10) are inductors, and (13) are ignition signal generators. The circuits (17) to (17,) are high voltage generation circuits. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A low-voltage power distribution type capacitor discharge type ignition device for an internal combustion engine with an extended discharge duration, comprising: first and second rectifier elements that rectify a boosted DC power supply voltage; and an output of the rectifier elements. The first and second capacitors to be charged respectively, the inductor for extending the discharge duration provided in the discharge path of the second capacitor, and the engine so as to share one set of the rectifying element, the capacitor and the inductor. a high-pressure generation circuit provided corresponding to each cylinder, the high-pressure generation circuit comprising an ignition coil, a first switching element that forms a discharge path for the capacitor via the ignition coil, the inductor, and the ignition coil. An ignition device for an internal combustion engine, comprising a second switching element forming a current path through the ignition coil, and a third rectifying element connected to the primary side of the ignition coil.