JP2011185163A - Ignition device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition device for an internal combustion engine capable of surely avoiding a runaway in an igniter even if an excess current is generated as the result of a failure inside the igniter. <P>SOLUTION: The ignition device 1 for an internal combustion engine uses an igniter 4 to control a current passed from a battery power source 5 to a primary coil 31 of an ignition coil 3. When an ignition control signal is inputted from an engine control unit 2 to a base 41B of a power transistor 41 that the igniter 4 has, a current is controlled to be either passed or shut between a collector 41C and an emitter 41E. The emitter 41E of the power transistor 41 is electrically connected to an emitter connection element 8 via a fuse element 7, so that when a large current flows between the collector 41C and the emitter 41E of the power transistor 41 and generates an abnormally high temperature, the fuse element 7 is fused and the power transistor 41 stops operating. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine ignition device including an igniter that generates a high voltage on a secondary side of a coil by energizing / cutting off a primary current flowing through an ignition coil in accordance with an ignition signal output from an engine control unit. About.

  An ignition device for an internal combustion engine is disposed for each cylinder of an engine, and a primary coil, a secondary coil disposed outside the primary coil, and the secondary coil and the primary coil are magnetically coupled in an insulating case. And an igniter including a power transistor that controls a primary current flowing in the primary coil of the ignition coil.

  Here, a conventional igniter for an internal combustion engine ignition device, for example, a one-chip type igniter, includes a power transistor that controls energization / cutoff of a primary current flowing through a primary coil, and a circuit element that limits the primary current flowing through the primary coil. Are developed in one semiconductor chip. The power transistor includes a gate portion connected to the engine control device, an emitter portion connected to the ground, and a collector portion connected to the primary coil. The circuit element protects the power transistor by limiting the current flowing from the collector part to the emitter part of the power transistor.

  The igniter prevents abnormal heat generation by avoiding a continuous energization state by a circuit element, prevents deterioration and destruction of a power transistor as a component, and thus prevents melting and ignition of an ignition coil for an internal combustion engine. Therefore, an invention has been proposed in which an igniter is provided with a function of restricting the flow rate or forcibly shutting off the circuit when the flow rate of the current in the circuit or the heat generation temperature reaches a specified value (see, for example, Patent Document 1).

JP 2001-248529 A

  However, in the invention described in Patent Document 1, when any short circuit (failure) occurs between the collector part and the emitter part in the power transistor, the protection mechanism of the circuit element does not work. There is a problem in that no restriction or forced shut-off is performed, abnormal heating occurs due to a continuous energization state, causing melting of an ignition coil for an internal combustion engine, ignition, and engine malfunction. In particular, in the worst case, if the vehicle fuse blows due to abnormal heat generation due to excessive current, the vehicle fuse of the engine system is usually one system, so that the engine stops and cannot be restarted. there is a possibility.

  Therefore, an object of the present invention is to provide an internal combustion engine ignition device that can reliably prevent runaway in the igniter even if an overcurrent occurs due to an abnormality in the igniter.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that the primary current flowing through the ignition coil is energized / interrupted in accordance with the ignition signal output from the engine control unit, so that the coil secondary side is increased. An ignition device for an internal combustion engine including an igniter for generating a voltage, wherein a fuse element is used for an electrode portion on a semiconductor chip constituting the igniter, and the fuse is turned into an uncontrollable state due to a short circuit of the element or the like It is characterized in that an overcurrent is prevented from flowing intermittently by the function of the element.

  The invention according to claim 2 is the ignition device for an internal combustion engine according to claim 1, wherein the fuse element of the igniter is blown when an excessive current flows through a thin film electrode formed on the semiconductor chip. The fusing part of the narrow path structure to provide is provided.

  According to the first aspect of the present invention, a fuse element is used for an electrode portion on a semiconductor chip constituting the igniter, and the fuse element functions when the igniter falls into an uncontrollable state due to a short circuit of the element or the like. Since the overcurrent is prevented from flowing intermittently, even if an overcurrent occurs due to an abnormal operation of the internal circuit of the igniter, the fuse element functions, so that an excessive current continues to flow through the ignition coil. It is possible to prevent damages and malfunctions, and it is possible to reliably avoid an engine stop or a restart impossible state caused by a blown vehicle fuse.

  Further, according to the invention according to claim 2, since the fuse element of the igniter is provided with a fusing part having a narrow path structure that blows when an excessive current flows in the thin film electrode formed on the semiconductor chip, A fuse element can be formed on a semiconductor chip by a semiconductor thin film forming technique, the igniter manufacturing process is not complicated, and a reliable circuit interruption by a fusing part is possible.

1 is a schematic configuration diagram showing an embodiment of an internal combustion engine ignition device according to the present invention. It is an internal perspective view of an igniter. It is a schematic sectional drawing of the electrode part in the semiconductor chip of an igniter. (A) It is the 1st block diagram of the fuse element which provided the fusing part. (B) It is the 2nd block diagram of the fuse element which provided the fusing part.

  Next, an embodiment of an ignition device for an internal combustion engine according to the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the internal combustion engine ignition device 1 according to the present embodiment controls energization / interruption of the primary current flowing through the primary coil 31 of the ignition coil 3 in accordance with an ignition control signal from the engine control unit 2. An igniter 4 is provided. By controlling the energization of the igniter 4, the current from the battery power source 5 to the primary coil 31 is controlled, the induced power of the secondary coil 32 magnetically coupled via the iron core 33 is controlled, and an electric spark is generated in the discharge gap. Although the internal combustion engine ignition device 1 is provided for each cylinder, a single system vehicle fuse 6 is provided between the battery power source 5 and each internal combustion engine ignition device 1, and the vehicle fuse is caused by overcurrent. When 6 melts, power supply to all cylinders stops.

  The igniter 4 includes a power transistor 41. When an ignition control signal is input from the engine control unit 2 to the base 41B of the power transistor 41, energization / cutoff between the collector 41C and the emitter 41E is controlled.

  Here, it is assumed that the emitter 41E of the power transistor 41 is electrically connected to the emitter conduction terminal 8 through the fuse element 7. When a large current flows between the collector 41C and the emitter 41E of the power transistor 41 and the temperature becomes abnormally high, Since the element 7 is melted, the emitter 41E and the emitter conduction terminal 8 of the power transistor 41 are cut off, and the power transistor 41 does not operate, so that a malfunction due to excessive current flowing through the ignition coil 3 can be prevented. Furthermore, it is possible to reliably avoid the engine stop or the restart impossible state due to the fusing of the vehicle fuse 6.

  As the fuse element 7 described above, an electrode body made of a low melting point fusible alloy may be attached to the chip. However, as shown in FIG. 2 and FIG. If it is formed as a thin film electrode on a semiconductor chip 9 (a small chip in which an electronic circuit is formed by laminating a conductive layer 92 and an insulating layer 93 on a semiconductor substrate 91) forming the power transistor 4, a fuse element 7 is provided to provide an igniter. 7 can be prevented from being complicated. Note that the fuse element 7 having a thin film electrode structure and the emitter conduction terminal 8 are conducted through an aluminum wire 42 formed by wire bonding.

  Further, the fuse element 7 having a thin film electrode structure can be surely disconnected by fusing on the insulating layer 92 of the semiconductor chip 9 when an overcurrent is generated. You may make it provide the melt | fusion part which is easy to melt | fuse when an overcurrent generate | occur | produces without setting it as a structure.

  For example, like the fuse element 71 of the first configuration example shown in FIG. 4A, a fusing part 71a having a narrow channel structure in a part of the flow path is provided, or the second configuration example shown in FIG. 4B. If a melted portion 72a having a narrow path structure with an extremely narrow part of the conductor width is provided as in the fuse element 72, the melted portions 71a and 72a are quickly melted when an excessive current flows. It is possible to reliably perform circuit interruption. In addition, you may provide the fusing part of a narrow path structure by making thickness of a part in thin film electrode thin.

  In addition, if the thin film electrode fuse element 7 is formed using the recent high-level thin film formation technology, the accuracy of the electrode shape (particularly the accuracy of the fusing part) can be increased. Therefore, it is possible to suppress the occurrence of extreme variations and to ensure the reliability of the apparatus.

  As mentioned above, although embodiment of this invention was described based on the accompanying drawing, this invention is not limited to this embodiment, You may implement by diverting well-known existing equivalent technical means. . For example, not only a so-called one-chip igniter in which a control circuit is integrated on a single semiconductor chip, but also a multi-chip type in which a power transistor and a control circuit are separated, a hybrid type in which a control circuit is formed on a mixed integrated substrate, and the like. The present invention is applicable to any transistor as long as a fuse element can be formed on the emitter electrode of the transistor.

DESCRIPTION OF SYMBOLS 1 Ignition device for internal combustion engines 2 Engine control unit 3 Ignition coil 31 Primary coil 32 Secondary coil 33 Iron core 4 Igniter 41 Power transistor 41B Base 41C Collector 41E Emitter 42 Aluminum wire 5 Battery power supply 6 Vehicle fuse 7 Fuse element (thin film electrode)
8 Emitter conduction terminal 9 Semiconductor chip 91 Semiconductor substrate 92 Conductive layer 93 Insulating layer

Claims (2)

In accordance with an ignition signal output from an engine control unit, an ignition device for an internal combustion engine including an igniter that generates a high voltage on a secondary side of a coil by controlling energization / cutoff of a primary current flowing through an ignition coil,
When a fuse element is used for the electrode part on the semiconductor chip constituting the igniter, and the igniter falls into an uncontrollable state due to a short circuit of the element or the like, the fuse element functions so that overcurrent flows intermittently. An ignition device for an internal combustion engine, characterized in that it is prevented.   2. The internal combustion engine for an internal combustion engine according to claim 1, wherein the fuse element of the igniter is provided with a fusing portion having a narrow path structure that blows when an excessive current flows in a thin film electrode formed on a semiconductor chip. Ignition device.

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