JP2006242179A - Ignition device for internal combustion engines - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an ignition device from malfunctioning by influence of an external electric field. <P>SOLUTION: An electric wave current generated in a signal wire. which connects an ECU 10 with the ignition device 1 by influence of the strong electric field, by a capacitor 6 provided in a parallel circuit in a connector part bypasses the capacitor 6 without passing through a Zener diode 3, and rectification of the Zener diode 3 is not caused. Accordingly, the potential level of the signal wire to input an ignition signal in an igniter 5 rises, and the ignition device 1 is prevented from malfunctioning. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ignition device for an internal combustion engine (hereinafter simply referred to as an ignition device) in which an igniter is incorporated in an ignition coil.

Conventionally, an ignition device has been devised that incorporates an igniter in an ignition coil and controls the ignition timing of the internal combustion engine by controlling energization to the ignition coil (see, for example, Patent Document 1).
In such an ignition device, as shown in the circuit diagram of FIG. 6, a switching element portion that performs switching of a coil current flowing through the ignition coil is connected to a Zener diode 200 that is a protection element that protects against an external surge or the like. is there.
Specifically, the Zener diode 200 has a cathode connected to the input side where an ignition signal is input to the switching element unit, and an anode connected to the GND side. By being connected in this way, even if an external surge occurs, it can be prevented that a high voltage is applied to the igniter 300 by the voltage clamp function of the Zener diode 200.

JP-A-6-317243

In recent years, an ignition device in which an igniter is built in an ignition coil is often mounted immediately above a cylinder of an internal combustion engine (hereinafter referred to as an engine). For this reason, the length of a signal line that electrically connects a control unit (hereinafter referred to as ECU) that controls the engine and the ignition device tends to increase, and the wiring capacity tends to increase.
In such a situation, as shown in FIG. 6, in a circuit including a Zener diode 200 having a cathode connected to the input terminal side and an anode connected to the GND terminal side, a broadcasting station, a radio, or the like is used near the signal line. When a radio wave current is generated in a strong electric field, only a positive potential is stored in the wiring capacitance due to the rectifying action of the Zener diode. Then, the low level voltage of the input terminal rises. For example, although the potential level of the ignition input signal of the signal line must be low level, the igniter 300 has an incorrect potential. Under the level signal, the switching element 100 may be turned on, which may cause a problem that the ignition device malfunctions.
In view of the above problems, an object of the present invention is to provide an ignition device for an internal combustion engine that prevents the ignition device from malfunctioning due to the rectifying action of a protective element.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided an ignition coil and switching of a coil current that is built in the ignition coil and is caused to flow through the ignition coil based on an ignition signal output from a control unit of an internal combustion engine. A switching element unit for performing the above, an igniter having a Zener diode between the input side of the ignition signal and GND as a protective element of the switching element unit, and the control unit and the input of the ignition signal An input terminal electrically connected to the side, a connector for sending the ignition signal output from the control unit to the igniter via the input terminal, and a connector provided in the connector, the input terminal and the GND And a parallel circuit having a capacitor in between.

According to the ignition device having such a configuration, the radio wave current generated in the signal line of the ignition signal input to the igniter due to the influence of the strong electric field is not transmitted through the Zener diode by the capacitor provided in the parallel circuit in the connector. The capacitor is bypassed, and the rectifying action of the Zener diode does not occur.
Therefore, it is possible to suppress the occurrence of a phenomenon that the potential level of the signal line becomes an incorrect level due to the influence of a strong electric field, and to prevent a signal having an incorrect potential level from being input to the igniter. Thereby, it is possible to prevent malfunction of the ignition device such that the switching element is erroneously turned ON.

In the ignition device having such a configuration, as shown in claim 2, after the pre-molded body in which the input terminal and the GND terminal are integrated with the resin is formed in advance, the connector is formed into a predetermined connector shape. The pre-molded product may further include a capacitor connection terminal for connecting the capacitor to the parallel circuit.
Since the capacitor connection terminal can be arranged at a desired position by integrally forming the capacitor connection terminal with the pre-molded body in this way, it is possible to reliably connect the capacitor connection terminal to the capacitor connection terminal when the capacitor is mounted. .

According to a third aspect of the present invention, the connector may be provided with a concave capacitor housing portion for housing the capacitor.
Thereby, since it can hold | maintain stably at the time of capacitor | condenser installation, reliable electrical connection to a capacitor | condenser connection terminal is attained.
Furthermore, as shown in claim 4, after the capacitor is accommodated in the capacitor accommodating portion, silicon may be filled so as to cover the capacitor. Thereby, the thermal stress due to the thermal stress can be relaxed with respect to the capacitor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.
(First embodiment)
Hereinafter, a vehicle ignition device to which an embodiment of the present invention is applied will be described.
FIG. 1 is a circuit configuration diagram of an ignition device 1 in the present embodiment. Moreover, FIG. 2 is sectional drawing of the ignition device 1 in this embodiment. Furthermore, FIG. 3 is a top view of the ignition device 1 in the present embodiment, and FIG. 4 is an explanatory diagram showing a molding procedure of the connector portion of the ignition device 1 in the present embodiment. The ignition device 1 in the present embodiment will be described with reference to these drawings.

As shown in FIG. 1, the ignition device 1 includes an ignition coil 4 and an igniter 5.
The igniter 5 includes a switching element unit 2 that performs switching control of energization to the primary winding 4 a of the ignition coil 4.
The gate to the switching element unit 2 is connected to the input side 7 to the igniter 5 so that an ignition input signal (ignition signal) from the ECU 10 which is a control unit of an internal combustion engine (not shown) is input. It has become. When the potential level of the gate voltage of the switching element unit 2 becomes high level, the switching element is turned on, energization to the primary winding 4a in the ignition coil 4 is performed, and switching is performed when the potential level of the gate voltage becomes low level. The element is turned off, and the energization to the primary winding 4a is cut off.

  The igniter 5 includes a Zener diode 3 as a protection element. The Zener diode 3 has a cathode terminal connected to an input side line in the igniter that is electrically connected to the input side 7 to which an ignition signal is input from the ECU 10, while an anode terminal is connected to the GND side 8 in the igniter 5. It is connected to the GND side line. The zener diode 3 protects the switching element portion 2 that performs switching of the coil current flowing through the ignition coil 4 from an external surge or the like.

Further, the coil device 1 is provided with a parallel circuit in which a capacitor 6 is connected between the input side 7 and the GND side 8.
The input side 7 and the GND side 8 are electrically connected to an ignition signal input terminal 16 and a GND terminal 17 which are external terminals provided in a connector portion 15 of the ignition device 1 described later. The ignition signal input terminal 16 is connected to the ECU 10 via a signal line, and the GND terminal 17 is electrically grounded via a harness (not shown).

The ignition device 1 having the above-described circuit configuration is specifically shown by a cross-sectional view of FIG. 2 and a top view of FIG.
The ignition coil 4 of the ignition device 1 is accommodated in a coil case 30 made of resin. The coil case 30 is open at the top in the figure, and the ignition coil 4 is accommodated from the opening. Furthermore, the igniter 5 and the capacitor 6 are accommodated between the ignition coil 4 and the connector portion 15 side formed integrally with the coil case 30. As will be described later, the connector portion 15 has an external terminal for electrical connection with the outside, and the coil case 30 is electrically connected to the external terminal, the igniter 5, the capacitor 6, and the ignition coil 4. By filling the epoxy resin 31 from the opening, the ignition coil 4 is fixed and held in the coil case 30 in an electrically insulated state.

In addition, before the epoxy resin 31 is filled, the silicon adhesive 32 covers the entire igniter 5 and the capacitor 6 in a state where the igniter 5 and the capacitor 6 are accommodated in the coil case 30 and electrically connected. Is filled. The silicon adhesive 32 can relieve stress generated in the igniter 5 and the capacitor 6.
In FIG. 2, a spring 33 is provided on the lower side of the ignition coil 4 in the drawing. The spring 33 is connected to the secondary winding 4b of the ignition coil 4 and to an ignition plug (not shown).

Next, a procedure for forming the connector portion 15 will be described with reference to FIG.
As shown in FIG. 4A, the terminal integrally held by the connector portion 15 is composed of three metal members, and one end side serving as an external terminal is formed in a plate shape, and all the three are parallel to each other. It is arranged to become. The three external terminals are an ignition signal input terminal 16 connected to the ECU 10 via a signal line, a GND terminal 17 connected to the external ground, and a battery terminal 18 connected to the battery.
The other ends of these three terminals are extended to serve as metal terminals for making a predetermined connection in the ignition device 1.

The other end side of the ignition signal input terminal 16 connected by the ignition device 1 is connected to the input side 7 to the igniter 5 as described above. Furthermore, this terminal 16 branches off in the middle, and a projection is formed as a capacitor connection terminal 16a for connection to the capacitor 6. Similarly, the other end side of the GND terminal 17 connected in the ignition device 1 is connected to the GND side 8 to the igniter 5 and connected to the capacitor 6 in the middle thereof, as described above. A protrusion is formed as a capacitor connection terminal 17a.
Note that the other ends of the ignition signal input terminal 16 and the GND terminal 17 are formed with bent portions that are bent upward, that is, at a right angle in the drawing. Similarly, a bent portion is formed on the other end side of the battery terminal 18.

Then, the terminals 16, 17, and 18 thus formed are integrally molded with three terminals as shown in FIG. 4B in the position state shown in FIG. A molded product 50 is formed.
Then, the pre-molded body 50 in which these three terminals are integrated with resin is set in a predetermined mold and filled with resin, so that the ignition device 1 of FIG. The connector portion 15 is formed (along with this, the coil case 30 is also resin-molded).
The connector portion 15 is resin-molded so that the capacitor connection terminals 16a and 17a are exposed to the outside, and part of the bent portions of the terminals 16, 17, and 18 are also exposed to the outside. These externally exposed terminals are configured as terminals for electrically connecting the capacitor 6 and the igniter 5.

Thus, by forming the pre-molded body 50 and resin molding the connector portion 15, a connector portion in which a plurality of terminal portions are reliably positioned at desired positions can be obtained.
Further, after the capacitor connection terminals 16a and 17a and the metal terminals provided with bent portions on the other end sides of the terminals 16, 17, and 18 are formed into pre-molded bodies, the connector portion 15 is resin-molded to form the igniter 5 In addition, the connection terminals for the capacitor 6 are formed, so that each connection terminal positioned with high accuracy can be obtained. For this reason, when the igniter 5 and the capacitor 6 are attached, reliable electrical connection can be easily achieved.

Further, as shown in FIG. 4C, simultaneously with the molding of the connector portion 15, a concave igniter accommodating portion 51 and a capacitor accommodating portion 52 for accommodating the igniter 5 and the capacitor 6 are formed. The groove widths of the accommodating portions 51 and 52 are formed with dimensions corresponding to the element widths of the igniter 5 and the capacitor 6. When the accommodating portions 51 and 52 are accommodated in the accommodating portions, they are wobbled and the electrical connection is unstable. It is devised not to become.
With this configuration of the accommodating portion, it is possible to achieve reliable electrical connection when the igniter 5 and the capacitor 6 are attached.

As described above, the ignition device 1 is configured. Then, the primary winding 4a of the ignition coil 4 is connected to the collector terminal of the switching element provided in the switching element unit 2, and the secondary winding 4b of the ignition coil 4 is connected to the ignition plug. A high voltage is applied to the spark plug by the ignition device 1.
The ignition device 1 is controlled by receiving an ignition input signal (ignition signal) from the ECU 10 via a signal line externally connected to the connector unit 15. When the ignition input signal becomes high level, a high gate voltage is applied to the switching element, and the switching element is turned on. For this reason, a current flows between the collector and the emitter of the switching element, and a coil current flows in the primary winding 4 a of the ignition coil 4. On the other hand, when the ignition signal from the ECU 10 becomes a low level, the gate voltage of the switching element decreases, so that the element is turned off and the coil current to the primary winding 4a of the ignition coil 4 is interrupted.

By controlling the coil current that flows in the primary winding 4a by switching control to such a switching element, a current necessary for discharging the spark plug flows from the secondary winding 4b, and ignition is performed in the internal combustion engine. Is called.
According to the ignition device having such a configuration, the radio wave current generated in the signal line connecting the ECU 10 and the ignition device 1 due to the influence of the strong electric field by the capacitor 6 provided in the parallel circuit in the connector portion 15 is converted into a Zener diode. Therefore, the capacitor 6 is bypassed without passing through 3, and the rectifying action of the Zener diode 3 does not occur.

Therefore, it is possible to suppress the occurrence of a phenomenon in which the potential level of the signal line becomes an incorrect level due to the influence of a strong electric field, and to prevent a signal having an incorrect potential level from being input to the igniter 5. Thereby, it is possible to prevent malfunction of the ignition device such that the switching element is erroneously turned ON.
Note that the capacity of the capacitor 6 needs to be at least 1000 pF in order to obtain the above effect, and it has been confirmed by experiments by the inventors that 2200 pF is suitable in consideration of ignition delay.

(Second Embodiment)
A second embodiment of the present invention will be described. This embodiment shows an example in which the parallel circuit in the connector unit 15 is replaced with a series circuit with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Only will be described.
FIG. 5 is a circuit configuration diagram of the ignition device 1 in the present embodiment. As shown in this figure, an inductance 60 is provided in series on the input side 7 to the igniter 5.

With this configuration, the radio wave current generated in the signal line connecting the ECU 10 and the ignition device 1 due to the strong electric field is blocked from flowing to the igniter 5 due to the impedance of the inductance 60.
Therefore, it is possible to suppress the occurrence of a phenomenon in which the potential level of the signal line becomes an incorrect level due to the influence of a strong electric field, and to prevent a signal having an incorrect potential level from being input to the igniter 5. Thereby, it is possible to prevent malfunction of the ignition device such that the switching element is erroneously turned ON.

In the above-described embodiment, an example in which a Zener diode is used between the ignition signal input side of the igniter 5 and GND is described. However, a so-called general diode may be used.
In the above-described embodiment, the example in which the capacitor 6 and the inductance 7 are provided outside the igniter 5 has been described. However, the capacitor 6 and the inductance 7 may be provided inside the igniter 5.
Further, in the above-described embodiment, an example in which a Zener diode is provided between the ignition signal input side and the GND inside the igniter 5 is described. However, a Zener diode or a diode may be provided outside the igniter 5. .

It is a circuit block diagram of the ignition device in 1st Embodiment of this invention. It is sectional drawing of the ignition device shown in FIG. FIG. 3 is a top view of FIG. 2. It is explanatory drawing which shows the shaping | molding procedure of the connector part of the ignition device of FIG. 1, (a) is a perspective view of a terminal part, (b) is a perspective view of a premolding body, (c) is a connector part. It is a perspective view. It is a circuit block diagram of the ignition device in 2nd Embodiment of this invention. It is a circuit block diagram of the conventional ignition device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition device 2 Switching element 3 Zener diode 4 Ignition coil 4a Primary winding 4b Secondary winding 5 Igniter 6 Capacitor 7 Input side 8 GND side 10 ECU
15 Connector portion 16 Ignition signal input terminal 17 GND terminal 32 Silicon 50 Pre-molded body

Claims (4)

An ignition coil;
A switching element portion that is built in the ignition coil and performs switching of a coil current that flows through the ignition coil based on an ignition signal that is output from a control unit of the internal combustion engine, and a protection element for the switching element portion. An igniter having a Zener diode between the input side and GND;
The ignition unit is electrically connected to the control unit and has an input terminal electrically connected to the input side of the ignition signal, and the ignition signal output from the control unit via the input terminal is transmitted to the igniter. A connector to send to,
An internal combustion engine ignition device comprising: a parallel circuit provided in the connector and having a capacitor between the input terminal and GND. The connector is formed in a predetermined connector shape after forming a pre-molded body in which the input terminal and the GND terminal connected to the GND are integrated with a resin in advance.
The ignition device for an internal combustion engine according to claim 1, wherein the pre-molded body further includes a capacitor connection terminal for connecting the capacitor to the parallel circuit.   The ignition device for an internal combustion engine according to claim 2, wherein the connector includes a concave capacitor housing portion that houses the capacitor.   4. The internal combustion engine ignition device according to claim 3, wherein after the capacitor is accommodated in the capacitor accommodating portion, silicon is filled so as to cover the capacitor.

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