JP2009203852A - Power switch unit for internal combustion engine ignition coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power switch unit capable of securing safety of an engine system for an automobile or the like without stopping an engine by carrying out electric separation when there is failure due to some cause. <P>SOLUTION: The power switch unit 1 for an internal combustion engine ignition coil is equipped in one semiconductor chip 2 with a power transistor 3 and a circuit element 4 controlling energization/non-energization of a primary current flowing through a primary coil 8 in response an ignition control signal from an engine controller, and a collector terminal 7 connected to the primary coil 8. Particularly, it is composed such that a collector 31 of the power transistor 3 and the collector terminal 7 are connected by solder 9, and the solder 9 is placed in a groove 10 provided in the power switch unit 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power switch unit used for an ignition coil for an internal combustion engine such as an automobile. When a failure occurs for some reason, it is electrically separated and the engine system of the automobile or the like is not stopped without stopping the engine. The present invention relates to a power switch unit of an ignition coil for an internal combustion engine that can ensure safety.

  The ignition coil for an internal combustion engine is arranged for each cylinder of the engine, and includes at least a primary coil, a secondary coil arranged outside the primary coil, the secondary coil and the primary coil in an insulating case. A coil-core assembly composed of a magnetically coupled iron core is housed, and further, an external terminal (collector terminal) whose one end is connected to the primary coil in the coil-iron core assembly and a primary current flowing through the primary coil are controlled. A power switch unit including a power transistor and a circuit element are accommodated, and subsequently filled with an insulating resin and cured. In general, dimensional restrictions required from other engine parts and the like are severe, and miniaturization is required. In addition, in order to bring about a severe thermal environment such as a temperature range of 30 ° C. to 130 ° C. below the freezing point, various types have been conventionally used to guarantee sufficient durability for the power switch unit housed in the insulating case. Design considerations are being considered.

Here, as shown in FIGS. 5 to 7, the conventional power switch unit of the ignition coil for an internal combustion engine, for example, the one-chip type power switch unit 1 turns on / off the primary current flowing through the primary coil 8. The power transistor 3 controlled by turning off and the circuit element 4 for limiting the primary current flowing through the primary coil 8 are developed in one semiconductor chip 2. The power transistor 3 is connected to the engine control device via a base terminal 6 which is one external terminal, connected to the ground via an emitter terminal 5 which is another external terminal, and a collector terminal which is another external terminal. 7 to the primary coil 8.
The circuit element 4 protects the power transistor 3 by limiting a current flowing through the power transistor 3, and is disposed between the base and the emitter of the power transistor 3.
The invention relating to such a power switch unit 1 is proposed in, for example, the following Patent Document 1, the following Patent Document 2, and the like.
JP 2001-248529 A JP 2000-297732 A

  In addition, when an engine system such as an automobile has a malfunction in the ignition coil for the internal combustion engine or the power switch unit 1 itself, these are arranged for each cylinder of the engine. It is constructed so that the state can be maintained, the state in which retreating can be performed is maintained, and the dangerous state due to the engine stop is avoided.

  However, the conventional one-chip type power switch unit 1 is in a continuously energized state because the protection mechanism of the circuit element 4 does not work when the power transistor 3 itself is short-circuited (failed) due to some abnormality. In addition to the malfunction of the engine, in the worst case, the vehicle fuse is blown by abnormal heat generation due to continuous energization. In this case, the engine system has a problem that it may cause an engine stop because the vehicle fuse is usually one system. That is, there is a possibility that a failure of the ignition coil for the internal combustion engine or the power switch unit 1 arranged in one cylinder may cause the entire engine system to stop, and it is possible to fall into a very dangerous state in which retreat traveling is impossible. was there.

  The present invention has been proposed in view of the above circumstances, and even when a failure occurs for some reason, by electrically separating itself before the vehicle fuse is blown, without stopping the engine, An object of the present invention is to provide a power switch unit that can ensure the safety of an engine system such as an automobile.

  In order to achieve the above object, a power switch unit of an ignition coil for an internal combustion engine according to the present invention is a power transistor that controls energization / non-energization of a primary current flowing in a primary coil in accordance with an ignition control signal from an engine control device. In the power switch unit of the ignition coil for an internal combustion engine provided with an external terminal connected to the primary coil, the external terminal and the power transistor are connected by solder. It is characterized by that.

  And it is preferable that the said power switch unit is equipped with the groove | channel where solder is arrange | positioned, and is molded by insulating resin in the state in which a part of this groove | channel appears in an external appearance.

  In the present invention, a power transistor and a circuit element for controlling energization / non-energization of a primary current flowing in the primary coil according to an ignition control signal from the engine control device are provided in one semiconductor chip and connected to the primary coil. In an internal combustion engine ignition coil power switch unit having an external terminal, the external terminal and the power transistor are connected by soldering. Even if the power switch unit fails for some reason and generates abnormal heat, the generated heat causes soldering. As the engine melts, the connection between the external terminal and the power transistor is disconnected, the energization to the primary coil is cut off, and the vehicle fuse is not blown even if the engine malfunctions, and the entire engine system stops. To ensure the safety of engine systems such as automobiles It can be.

  Further, the power switch unit includes a groove in which solder is disposed, and further, the groove is molded with an insulating resin in a state where a part of the groove appears on the appearance. Since the connection between the external terminal and the power transistor is disconnected and the energization to the primary coil is easily cut off, the vehicle fuse is surely prevented from fusing and the entire engine system is stopped. Therefore, the safety of an engine system such as an automobile can be ensured.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic front view showing an external appearance when a power switch unit of an ignition coil for an internal combustion engine according to the present invention is molded, and FIG. 2 is an internal structure of the power switch unit of the ignition coil for an internal combustion engine according to the present invention. FIG. 3 is an explanatory diagram showing an outline of a circuit of a power switch unit of an ignition coil for an internal combustion engine according to the present invention, and FIG. 4 is a cross-sectional view taken along line AA in FIG. In addition, the same code | symbol is attached | subjected to the part which is the same as that of the part shown as a prior art example in FIGS.

  The power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention is a one-chip type power switch unit 1 as shown in FIGS. 1 to 3, and the primary coil according to the ignition control signal from the engine control device. The power transistor 3 and the circuit element 4 that control energization / non-energization of the primary current flowing through the power transistor 8 are provided in one semiconductor chip 2, and the collector terminal 7 connected to the collector 31 of the power transistor 3 by the solder 9 is provided. It is what.

  In particular, as shown in FIGS. 2 and 4, the solder 9 connecting the collector 31 and the collector terminal 7 of the power transistor 3 is disposed in the groove 10 provided in the power switch unit 1. Further, as shown in FIG. 1, the groove 10 is configured such that a part of the groove 10 appears on the exterior when the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention is molded.

  Here, in the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention, a case where the power transistor 3 is damaged due to some cause and fails will be described.

  When the power transistor 3 is damaged and short-circuited, the power switch unit 1 enters a continuous energization state in which a primary current continues to flow through the primary coil 8. The power switch unit 1 in a continuous energization state generates heat, and when it reaches a certain temperature, the solder 9 connecting the collector 31 and the collector terminal 7 of the power transistor 3 starts to melt. The melted solder 9 flows out from a portion appearing in the appearance, which is a part thereof, along the groove 10 provided in the power switch unit 1. As a result, the collector 31 of the power transistor 3 and the collector terminal 7 are disconnected, and the power supply from the power switch unit 1 to the primary coil 8 is cut off. That is, the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention electrically separates itself from the entire engine system when the power transistor 3 is damaged and becomes short-circuited. The engine will stop, and it will not be in a very dangerous state where it is impossible to evacuate.

  Therefore, the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention is a one-chip type power switch unit 1, and in particular, the collector terminal 7 is connected to the collector 31 of the power transistor 3 by the solder 9. Therefore, even when the power transistor 3 is damaged and becomes short-circuited and the primary coil 8 continues to flow the primary current, the collector 31 and the collector terminal 7 of the power transistor 3 are connected. The solder 9 that has started to melt, and finally the connection between the collector 31 and the collector terminal 7 of the power transistor 3 is disconnected, so that the energization to the primary coil 8 can be cut off, and the electrical power from the entire engine system Can be separated. Since the vehicle fuse is not blown out, it is possible to prevent the engine from being stopped and being brought into a very dangerous state in which retreating is impossible.

  In particular, the solder 9 connecting the collector 31 of the power transistor 3 and the collector terminal 7 is disposed in the groove 10 provided in the power switch unit 1 and is insulated in a state where a part of the groove 10 appears on the appearance. Even if the power transistor 3 fails and the primary current continues to flow through the primary coil 8 because it is molded with resin, the collector 31 and the collector terminal 7 of the power transistor 3 are connected due to abnormal heat generation. Since the solder 9 that has started to melt and the melted solder 9 flows out from the portion that appeared in the appearance along the groove 10 that has been disposed, the collector 31 and the collector terminal of the power transistor 3 7 can be reliably disconnected, and the energization of the primary coil 8 can be cut off. Accordingly, the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention is electrically separated from the entire engine system by itself, so that the vehicle fuse is not blown, and the engine is stopped and cannot be retreated. , Can surely prevent falling into a very dangerous state.

  Note that the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention is connected to the collector 31 of the power transistor 3 due to abnormal heat generation even when the power switch unit 1 generates heat abnormally due to some abnormality of the circuit element 4. Since the solder 9 connected to the collector terminal 7 is melted and the melted solder 9 flows out from a portion appearing in the appearance, which is a part of the solder 9, to the outside. 3 is reliably disconnected from the collector terminal 7 and the primary coil 8 is de-energized so that it can be electrically separated from the entire engine system.

  As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to the said one Embodiment. The present invention can be modified in various ways without departing from the scope of the claims.

  For example, in the above embodiment, the solder 9 connecting the collector 31 and the collector terminal 7 of the power transistor 3 is disposed in the groove 10 provided in the power switch unit 1 of the ignition coil for an internal combustion engine according to the present invention. However, when the power switch unit of the ignition coil for the internal combustion engine abnormally generates heat, the solder is melted and the connection between the collector of the power transistor and the collector terminal is disconnected. It becomes. For example, the power switch unit of the ignition coil for an internal combustion engine is provided with a recess capable of storing melted solder so that the connection between the collector of the power transistor and the collector terminal can be reliably disconnected instead of the groove. May be. Then, since solder does not flow out of the power switch unit, there is no need to consider the risk of affecting other parts constituting the ignition coil for the internal combustion engine. It can be applied as a power switch unit.

It is a schematic front view which shows the external appearance when the power switch unit of the ignition coil for internal combustion engines which concerns on this invention is molded. It is a schematic front view which shows the internal structure of the power switch unit of the ignition coil for internal combustion engines which concerns on this invention. It is explanatory drawing which shows the outline | summary of the circuit of the power switch unit of the ignition coil for internal combustion engines which concerns on this invention. It is sectional drawing of the AA in FIG. It is a schematic front view which shows the external appearance when the conventional power switch unit is molded. It is a schematic front view which shows the internal structure of the conventional power switch unit. It is explanatory drawing which shows the outline | summary of the circuit of the conventional power switch unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power switch unit 2 Semiconductor chip 3 Power transistor 31 Power transistor collector 4 Circuit element 5 Emitter terminal 6 Base terminal 7 Collector terminal 8 Primary coil 9 Solder 10 Groove

Claims (2)

A power transistor and a circuit element for controlling energization / non-energization of a primary current flowing in the primary coil in response to an ignition control signal from the engine control device are provided in one semiconductor chip, and are external terminals connected to the primary coil In an internal combustion engine ignition coil power switch unit comprising:
The external terminal and the power transistor are connected by solder,
A power switch unit for an ignition coil for an internal combustion engine. The power switch unit of the ignition coil for an internal combustion engine according to claim 1,
A groove in which the solder is disposed;
Molded with insulating resin with a part of this groove appearing on the exterior,
A power switch unit for an ignition coil for an internal combustion engine.

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