JP2970146B2 - Electronic circuit unit, ignition device for internal combustion engine, and ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain an ignition device for an internal combustion engine which can conduct and interrupt large current and bear thermal fatigue. CONSTITUTION:A brass lead frame 6 is used for connection between a hybrid thick film substrate 3 in an ignition device and a terminal for external connection a2 for connecting and interrupting primary current of an ignition coil of the ignition device for internal combustion engine, and a brass lead wire is combined with the hybrid thick film substrate 3 through an iron nickel welding pad 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit unit in which an electronic circuit is provided on a hybrid substrate, and an ignition device for an internal combustion engine in which a current of a primary coil of an ignition coil is turned on and off by the electronic circuit to generate a high voltage. And an ignition timing control device for an internal combustion engine that controls the ignition timing according to the operating state of the engine.

[0002]

2. Description of the Related Art Generally, an electronic circuit including a power transistor and the like is formed on a hybrid substrate of ceramics (aluminum oxide). The primary current of the ignition coil is turned on and off by this electronic circuit, thereby generating a high voltage in the ignition coil. The primary current of this ignition coil is
It is guided to an external connection terminal provided in the unit case, and further supplied to an electronic circuit via a lead frame. Such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 64-83864.
No., published in Japanese Patent Application Publication No. Here, nickel is generally used as the lead frame, and the lead frame and the electronic circuit are connected by soldering.

[0003]

It has been desired to improve the ignition rate of the air-fuel mixture supplied to the internal combustion engine. Therefore, the primary current of the ignition coil has been increased. Here, if the lead frame for supplying the primary current of the ignition coil to the electronic circuit is made of nickel, the resistance is large, and if the primary current of the ignition coil is increased, the heat generation becomes excessively large and is not suitable as a lead frame.

Therefore, if the lead frame for supplying the primary current of the ignition coil to the electronic circuit is made of brass, such a problem can be solved. However, the hybrid thick film substrate of the electronic circuit is made of ceramics and has a significantly different coefficient of thermal expansion than brass.

[0005] The temperature of the internal combustion engine greatly increases from before the start to after the start. In the reverse process, the temperature drops significantly, and the temperature in the engine room in which the ignition unit case is disposed fluctuates greatly. Therefore, if the thermal expansion coefficients of the lead frame and the hybrid thick film substrate are significantly different, thermal stress is generated between the two. Since the temperature in the engine room rises and falls every time the internal combustion engine is started, thermal fatigue occurs between the lead frame and the electronic circuit on the hybrid thick-film substrate, and the electronic circuit on the lead frame and the hybrid thick-film substrate develops heat. There was a problem that the connection was disconnected.

An object of the present invention can supply a large current, and an electronic circuit unit that can withstand thermal fatigue, to provide an ignition timing control system for an ignition device and an internal combustion engine of the inner <br/> combustion engine It is in.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide an external connection terminal through which a primary current of an ignition coil flows, a hybrid thick film substrate made of aluminum oxide, and a supply through the external connection terminal. An ignition device for an internal combustion engine, comprising: an electronic circuit provided on the hybrid thick film substrate for conducting and blocking a current; a lead frame made of brass connected to the terminal for external connection; With a welding pad of
Are connected by welding the welding pad and the lead frame, further, it is achieved by the connection of the front Symbol welding pad and the electronic circuit is configured to connect by soldering. In addition, the above object is to provide an electronic circuit unit including an external connection terminal and an electronic circuit provided on a composite thick film substrate made of aluminum oxide, wherein the external connection terminal is connected to a connection portion of the electronic circuit. A lead frame made of brass, and a welding pad made of iron nickel, the lead frame and the welding pad are connected by welding, and the welding pad and a connection portion of the electronic circuit are connected by soldering. Achieved by doing The above object is also achieved by a sensor for detecting an operating state of an engine, an ignition timing calculating means for calculating an ignition timing according to an output signal of the sensor, a terminal for external connection through which a primary current of an ignition coil flows, Ignition of an internal combustion engine comprising an aluminum oxide composite thick film substrate provided with an electronic circuit for conducting and interrupting a current supplied through the external connection terminal in accordance with an output signal of an ignition timing calculation means In the timing control device, having a lead frame made of brass for connecting the terminal for external connection and the electronic circuit, and a welding pad made of iron nickel,
Connecting the lead frame and the welding pad by welding,
This is achieved by a configuration in which the connection portion between the welding pad and the electronic circuit is connected by soldering.

[0008]

[0009]

According to the present invention, the brass lead frame and the iron-nickel welding pad are firmly fixed by welding. Furthermore, since the thermal expansion coefficients of the iron-nickel welding pad and the aluminum oxide composite thick film substrate are similar, thermal fatigue hardly occurs between the two, and the iron-nickel welding pad and the electronic circuit It becomes difficult for the joint of the connection part by solder to be broken.

[0010]

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system configuration diagram showing a DI that supplies ignition energy from an ignition coil to each cylinder directly without a distributor.
It is an S (Direct Ignition System) type.

Ignition coils 11 to 16 (corresponding to a six-cylinder engine) provided for each cylinder are:
It has primary coils 21 to 26 and secondary coils 31 to 36. Each of the primary coils 21 to 26 has one end connected to the battery BT and the other end connected to the power module PM.
It is connected to the terminal a ₂ ~f ₂ for external connection.

The power module PM includes a number of power switches P _{SW1 to} P _SW6 corresponding to the number of cylinders. These power switches P _{SW1 to} P _SW6 are formed by one chip, and are jointly arranged on one board PL.

Further, the power module PM will be described. Darling Tontora Njisuta 41-46 two transistors T ₁ which are Darlington connected, respectively, T
₂ and resistors R ₁ and R ₂ . Transistor T ₁
The base ignition signal is input via the terminal a ₃ ~f ₃ and a resistor R ₃ for external connection from an engine control unit ECU. Darlington transistor 41
-46 transistors T ₁ of the collector - Zener diode Z _D between base, the collector of the transistor T ₂ - diode between the emitter are reversely connected.

The engine control unit ECU comprises:
From each of the sensors 37a to 37f, the crank rotation angle theta, the intake air amount Q _a, the engine water temperature T _W, an idle switch I _SW, knock intensity KNO, the ignition timing crowded take air O ₂ calculated power module PM and it outputs the signal to the terminal a ₃ ~f ₃ for external connection.

Next, the ignition operation of such a system configuration will be described.

When the key switch K _SW is closed, power is supplied from the battery BT to the ignition device via the fuse F. When the engine control unit ECU determines the energization time of the ignition device of the predetermined cylinder, the external connection terminal a ₃
To the high level. This current flows to the base of the first-stage transistor T ₁ of the Darlington transistor 41 through a resistor R _3. This current is amplified in the amplification factor h _fe times the transistor T _1, the collector of the transistor T ₁ - is fed to the base of the transistor T ₂ through emitter. The collector of the transistor T ₂ - Further amplification factor h _fe multiplied by the current of transistor T ₂ flows through the emitter.
At this time, the current excessively flowing through the Darlington transistor 41 may generate abnormal heat and be destroyed. Current limiting circuit IL ₁ in this order (IL ₁ ~IL ₆₎ is, is provided. Current limiting circuit IL ₁ detects the primary current, the 1
It operates when the secondary current exceeds a predetermined value (for example, 8 amps) to reduce the input current of the Darlington transistor 41 so that the primary current flowing through the primary coil 21 of the ignition coil 11 does not increase any more. work. In addition,
Current limiting circuit IL ₁ via the terminal GR for external connection diagram is grounded.

As described above, when the primary current flows through the primary coil 21, energy for ignition is stored in the primary coil 21. Thereafter, signals from an engine control unit ECU when the calculated predetermined energization time has elapsed is outputted to the terminal a ₃ ~f ₃ for external connection of the power module PM. Thus, the potential of the terminal a ₃ external connections becomes Low level.

When the input current of the Darlington transistor 41 is interrupted by a signal from the engine control unit ECU, the primary current is suddenly cut off, and at that time, the secondary coil 31 of the ignition coil 11 has a sharp rise due to electromagnetic induction. A voltage (secondary voltage) is generated.

The details of the power module PM will be described with reference to FIG. The unit case 1 made of resin has a hollow space, and the metal base 4 covers one opening.
Is provided. On the metal base 4, the hybrid thick film substrate 3 is provided. The composite thick film substrate 3 is formed by printing a thick film paste material on ceramics (aluminum oxide: Al ₂ O ₃ ), further applying heat thereto, and sintering to form conductors, resistors, insulators, etc. on the ceramics. It was done. Specifically, an electronic circuit including the power transistors T ₁ and T _{2 of the} power module PM shown in FIG. 2 is configured. Although the electronic circuit of the hybrid thick film substrate 3 generates heat during operation, the metal base 4 functions as a heat sink and radiates heat generated by the electronic circuit.

The resin unit case 1 has external connection terminals a ₂ (a ₂ to a ₂ ) for electrically connecting the inside and outside of the case.
f ₂ ) are integrally molded. The terminal a ₂ for external connection and the electronic circuit formed on the hybrid thick film substrate 3 are electrically connected by the lead frame 6 and the welding pad 5. The unit case 1 is filled with an electronic component protective material 7, and the terminals a ₂ for external connection, the composite thick film substrate 3, the lead frame 6 and the welding pad 5 are protected by the electronic component protective material 7.

Further, referring to FIG. 3, a terminal a for external connection will be described.
The connection between ₂ and the electronic circuit of the hybrid thick film substrate 3 will be described. The hybrid thick film substrate 3 is made of ceramics (aluminum oxide: Al ₂
O ₃ ) (linear expansion coefficient: about 7.0 × 10 ⁻⁶ /
° C). On the other hand, the welding pad 5 is made of iron-nickel (Fe-Ni
(Linear expansion coefficient: about 4.5 to 5.8 × 1)
0 ^-6 / ° C). Electronic circuit and welding pad 5 of hybrid thick film substrate 3
Are fixed by soldering. The lead frame 6 is made of brass (Cu-Zn alloy) (linear expansion coefficient, about 23 × 10 ⁻⁶ / ° C.). Furthermore, lead frame 6
And the welding pad 5 are fixed by welding. The terminal a ₂ for external connection are molded integrally with the unit case 1 is made of brass (Cu-Zn alloy), welding pad 5 and the terminal a ₂ for external connection is secured by soldering I have.

[0023] In this embodiment, subjected to binding of hybrid thick film substrate 3 and the terminal a ₂ for external connection using a lead frame 6 made of brass. For that reason, brass has low electric resistance,
A large current can flow through the hybrid thick film substrate 3.

Further, since the composite thick film substrate 3 is formed of ceramics and the welding pad 5 is formed of iron nickel, the linear expansion coefficient of the composite thick film substrate 3 is close to the linear expansion coefficient of the welding pad 5. ing. Therefore, thermal stress between the hybrid thick film substrate 3 and the welding pad 5 is reduced, and thermal fatigue is avoided. As a result, the composite thick plate 3 and the welding pad 5
During this time, peeling of the solder is avoided. The lead frame 6 and the welding pad 5 are firmly fixed because they can be fixed by welding.

Further, the connection between the hybrid thick film substrate 3 and the lead frame 6 will be described with reference to FIG. Conductor portions 17a and 17b are sintered on a ceramic substrate 18 of the hybrid thick film substrate 3. The circuit component 19 (resistance, etc.) is sintered between the conductors 17a and 17b. Conductor part 17a
Is used especially for connection with the lead frame 6 (connection part of an electronic circuit). That is, the conductor portion 17a and the welding pad 5 are fixed by the solder 20, and the welding pad 5
And the lead frame 6 are fixed by welding.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, the lead frame 6 and the terminal a ₂ for external connection are fixed using the welding pad 5.
The other parts are the same as in the first embodiment, and will not be described.

Next, a third embodiment will be described with reference to FIG. In the third embodiment, the unit case 4 is formed integrally with the molding resin of the ignition coil 11. The composite thick film substrate 3 is provided so as to overlap the unit case 4 formed integrally. The unit case 4 the molding resin of the ignition coil 11 are integrally formed, further, terminal a ₂ for external connection are integrally formed. The other parts are the same as in the first embodiment, and will not be described.

Next, a fourth embodiment will be described with reference to FIG. In the fourth embodiment, a terminal a ₂ for external connection is used.
Is bent perpendicular to the composite thick film substrate 3. Then, the part and the lead frame 6 by bending the terminal a ₂ for external connection is secured by welding. In addition,
The other parts are the same as in the third embodiment, and a description thereof will be omitted.

Next, a fifth embodiment will be described with reference to FIG. In the fifth embodiment, so as to bend the lead frame 6 in the shape of a flat plate vertically, to connect the terminal a ₂ and hybrid thick film substrate 3 for external connection. Here, the terminal a ₂ for external connection and the lead frame 6, the lead frame 6
And the welding pad 5 are respectively fixed by spot welding (welded portions 39 and 40).

Next, a reference example will be described with reference to FIG. In this reference example, the welding pad 5 is a clad material of an aluminum portion (Al) 51 and an iron nickel portion (Fe-Ni) 52. Further, the lead frame 6 using aluminum (Al) wire Ya. An aluminum lead frame 6 and an aluminum portion of the welding pad 5 are fixed by welding. Further, the electronic circuit of the hybrid thick film substrate 3 is fixed by soldering the iron nickel portion of the welding pad 5. Thus, electrically connecting the terminal a ₂ and hybrid thick film substrate 3 for external connection. Incidentally, the aluminum when compared to brass electric resistance is lower and the purpose, the use of aluminum wire Ya the lead frame 6, can supply a larger current to the electronic circuit of the hybrid thick film substrate 3.

Next, a sixth embodiment will be described with reference to FIG. In the sixth embodiment, the molding resin of the ignition coil 11 and the unit case 1 are integrally formed. Furthermore, by extending the terminal a ₂ for external connection,
It is directly connected to the primary coil 15 of the ignition coil 11 through the inside of the unit case 1 integrally formed with the molding resin of the ignition coil 11.
Note that the other parts are the same as in the third embodiment, and a description thereof will be omitted.

[0032]

As described above, according to the present invention,
The effect is obtained that a large current can be supplied to the electronic circuit of the hybrid thick film substrate and that it can withstand thermal fatigue.

[Brief description of the drawings]

FIG. 1 is a diagram showing details of a power module.

FIG. 2 is a system configuration diagram.

FIG. 3 is a diagram showing a connection between a terminal for external connection and a hybrid thick film substrate according to the first embodiment.

FIG. 4 is a view showing a connection portion of the electronic circuit between the lead frame and the hybrid thick film substrate according to the first embodiment.

FIG. 5 is a diagram showing a second embodiment.

FIG. 6 is a diagram showing a third embodiment.

FIG. 7 is a diagram showing a fourth embodiment.

FIG. 8 is a diagram showing a fifth embodiment.

FIG. 9 is a diagram showing a reference example.

FIG. 10 is a diagram showing a sixth embodiment.

[Explanation of symbols]

1 ... unit case, 3 ... hybrid thick film substrate, 4 ... metal base, 5 ... welding pad, 6 ... lead frame, 11 ... ignition coil, 37 ... sensor, a ₂ ... terminal for external connection, PM ... power module, ECU: Engine control unit.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Nori Urushibara 2520 Oaza Takaba, Katsuta-shi, Ibaraki Co., Ltd.In the Automotive Equipment Division of Hitachi, Ltd. Company Hitachi, Ltd. Automotive Equipment Division (56) References JP-A-64-83864 (JP, A) JP-A-2-152267 (JP, A) JP-A-63-20189 (JP, A) −185854 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 23/48 F02P 15/00 H01L 21/60

Claims (3)

(57) [Claims] 1. A terminal for external connection through which a primary current of an ignition coil flows, a composite thick film substrate made of aluminum oxide, and a terminal for conducting and interrupting a current supplied through the terminal for external connection. An ignition device for an internal combustion engine including an electronic circuit provided on a hybrid thick film substrate, comprising: a lead frame made of brass connected to the terminal for external connection; and a welding pad made of iron nickel; frame and the welding pad connected by welding, further, before Symbol welding pad and the ignition device for an internal combustion engine, characterized by being configured so that connection portions of the electronic circuit are connected by soldering. 2. An electronic circuit unit comprising an external connection terminal and an electronic circuit provided on a composite thick film substrate made of aluminum oxide, wherein the external connection terminal is connected to a connection portion of the electronic circuit. It has a lead frame made of brass and a welding pad made of iron nickel, the lead frame and the welding pad are connected by welding, and the welding pad and the connection portion of the electronic circuit are connected by soldering. An electronic circuit unit, characterized in that: 3. A sensor for detecting an operation state of an engine;
An ignition timing calculating means for calculating an ignition timing in accordance with an output signal of the sensor, a terminal for external connection through which a primary current of an ignition coil flows, and an external connection terminal in accordance with an output signal of the ignition timing calculating means. An ignition timing control device for an internal combustion engine including an aluminum oxide composite thick film substrate provided with an electronic circuit for conducting and interrupting a current supplied through a terminal, wherein the terminal for external connection and the electronic circuit and brass lead frames for connecting comprises a weld pad made of iron nickel, so that the connection with the lead frame by welding the welding pads, for connecting the connecting portion of the electronic circuit and the welding pad by soldering An ignition timing control device for an internal combustion engine, characterized in that: