JPH05172022A - Electronic equipment for load control, ignition device for internal combustion engine and electronic distributor and ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an electronic distributor for an internal combustion engine having the capability of controlling current flowing to other properly functioning power transistors, even if one of power transistors is shortcircuited. CONSTITUTION:The resistance values of lead frames 51 to 53 at the side of an ignition coil are set higher than the resistance value of a lead frame 57 at the side of the earth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load control electronic device for controlling a current flowing through an electric load, an ignition device for an internal combustion engine which generates a high voltage and supplies it to an ignition plug, and a high voltage for each cylinder. The present invention relates to an electronic distributor for an internal combustion engine that distributes power to a spark plug, and an ignition timing control device for an internal combustion engine that controls the timing of ignition of a mixture gas supplied to the internal combustion engine.

[0002]

2. Description of the Related Art There is an increasing number of cylinders of an internal combustion engine in which an ignition coil is arranged and a switching element such as a power transistor is arranged in correspondence with each ignition coil. With this configuration, the high voltage generated in the ignition coil can be distributed to the specific cylinder by specifying one of the plurality of switching elements to connect or disconnect.

As described above, the switching element is connected to each ignition coil, but this connection is made by connecting the respective lead frames. That is, at least the same number of lead frames (ignition coil side lead frames) as the switching elements are used to electrically connect the ignition coil and the switching elements. Moreover, the switching elements are dropped to a common ground. Here, each switching element is connected to a common lead frame (ground side lead frame) and then grounded. Such a technique is disclosed in, for example, JP-A 1-2
It is described in No. 59550.

Further, since a switching element such as a transistor is destroyed when an excessive current flows, a current limiting circuit is provided to limit the current flowing through the switching element. That is, the current flowing through the switching element is detected, and the current flowing through the switching element is limited when the current exceeds a predetermined value.

In the current limiting circuit, generally, the current flowing through the switching element is detected by the current detection resistor. Since this current detection resistor occupies a large area in the circuit board, the current detection resistor is commonly used. In such a case, a common current detection resistor is connected to a plurality of switching elements, and when the current flowing through this common current resistance exceeds a predetermined value, the currents flowing through all these switching elements are limited at the same time. Become.

[0006]

When some abnormal state occurs, one of the switching elements is burned and the switching element is fixed in the conductive state.
Overcurrent flows in the ignition coil side lead frame and the ground side lead frame. According to the conventional technique, one end of each switching element is connected to the ignition coil by the ignition coil side lead frame provided corresponding to each, but the other end of each switching element is
Collected and dropped to ground by a common ground side lead frame. If the earth side lead frame burns out due to overcurrent, no current will be supplied to all ignition coils, and not only the ignition coil connected to the abnormal switching element, but also other normally operating switching coils. No current flows in the ignition coil connected to the element.

A first object is to enable control of a current flowing through an ignition coil connected to another normally functioning switching element even if one of the plurality of switching elements is fixed in a conductive state. It is in.

In the prior art, a current limiting circuit is provided to limit the current flowing through the switching element.
When the current limiting circuit fails for some reason, the switching element is burned in, and in many cases, the switching element is fixed in the conductive state. At this time, an overcurrent is supplied to the ignition coil, and the ignition coil generates heat. In the worst case, the ignition coil burns.

A second object is to prevent overcurrent from flowing in the ignition coil and suppress heat generation in the ignition coil even if the current limiting circuit does not function sufficiently.

Further, in the above-mentioned conventional technique, the current detecting resistor is commonly used, and when the current flowing through the common current detecting resistor becomes a predetermined value or more, the switching element connected to the common current detecting resistor is used. The current flowing is uniformly limited. Therefore, for some reason, when the current flowing through one switching element among a plurality of switching elements exceeds a predetermined value, all the elements connected to the common current detection resistor, including the other switching elements that can function normally, are connected. The current flowing through the switching element is limited. As described above, in the above-described conventional technique, the current detection resistors are commonly used. Therefore, when a current more than a predetermined value flows through one of the switching elements, the functions of the other switching elements also stop, and this switching element It becomes impossible to control the current flowing through the ignition coil connected to the.

A third object is to control the current flowing in the ignition coil connected to the other switching element even if the current flowing in one of the switching elements connected to the common current detecting resistor exceeds a predetermined value. To enable

[0012]

In order to achieve the above first object, in the first configuration, a plurality of switching elements for individually conducting and cutting off the currents flowing through the plurality of ignition coils, and the plurality of switching elements are provided. A plurality of first lead frames for individually passing currents of switching elements to the plurality of ignition coils, and a single second lead for dropping currents of at least two switching elements of the plurality of switching elements to a common potential. And a frame, the resistance value of the first lead frame is set higher than the resistance value of the second lead frame.

Further, in order to achieve the above-mentioned first object, in the second configuration, a plurality of switching elements for individually conducting and cutting off the currents flowing through the plurality of ignition coils, and the currents of the plurality of switching elements are provided. A plurality of first lead frames that separately flow to the plurality of ignition coils,
A single second that drops the current of at least two switching elements among the plurality of switching elements to a common potential.
And a lead frame, the temperature coefficient of resistivity of the first lead frame is set larger than the temperature coefficient of resistivity of the second lead frame.

Further, in order to achieve the above first object, in the third configuration, a plurality of switching elements for individually conducting and cutting off the currents flowing through the plurality of ignition coils, and the currents of the plurality of switching elements are provided. A plurality of first lead frames that separately flow to the plurality of ignition coils,
A single second that drops the current of at least two switching elements among the plurality of switching elements to a common potential.
And a lead frame, the melting point of the first lead frame is set lower than the melting point of the second lead frame.

Further, in order to achieve the above-mentioned first object, in the fourth configuration, a plurality of switching elements for individually conducting and cutting off the currents flowing through the plurality of ignition coils, and the currents of the plurality of switching elements are provided. A plurality of first lead frames that separately flow to the plurality of ignition coils,
A single second that drops the current of at least two switching elements among the plurality of switching elements to a common potential.
A lead frame, at least one of both ends of the first lead frame is connected by solder, and the solder is melted when a current flowing through the first lead frame becomes a predetermined value or more. Then, it is configured to break the electrical connection.

In order to achieve the above second object, a fifth
In the configuration described above, a plurality of switching elements that separately conduct and block currents that flow in the plurality of ignition coils, and a current that flows in the switching element when the current that flows in the switching element becomes larger than a first predetermined value And a first current limiting unit for limiting the current flowing through the switching element when a current larger than the second predetermined value larger than the first predetermined value flows into the switching element. It had a second current limiting means.

In order to achieve the above-mentioned third object, the sixth
In the above configuration, a plurality of switching elements that separately conducts and cuts off the currents flowing through the plurality of ignition coils, a common current detection resistor into which the currents flowing through the plurality of switching elements flow, and a current flowing through the current detection resistors are predetermined. And a current limiting circuit that simultaneously interrupts the currents flowing through the plurality of switching elements when the value exceeds the resistance value of a conductor that electrically connects the ignition coil and the current detection resistor, It was set higher than the resistance value of the conductor that electrically connects the current detection resistor and the ground.

[0018]

[Function] The current from the battery flows in the order of the ignition coil, the ignition coil side lead frame, the switching element, the ground side lead frame, and the ground. According to the first configuration, when one of the switching elements is fixed in the conductive state, the overcurrent flows through the ignition coil side lead frame to the ground side lead frame, but the resistance value of the ignition coil side lead frame is Since the resistance value is set higher than the resistance value of the earth side lead frame, the heat generation amount of the ignition coil side lead frame becomes larger than the heat generation amount of the earth side lead frame. Therefore, the ignition coil side lead frame connected to the switching element in the abnormal state is melted and cut before the ground side lead frame. Therefore, the overcurrent from the ignition coil is not supplied to the earth side lead frame, the earth side lead frame is escaped from the melting due to the over current, and at least the ignition element connected to other properly functioning switching elements is ignited. It is possible to control the coil current.

According to the second configuration, when one of the switching elements is fixed to the conductive state, the overcurrent flows through the lead frame on the ignition coil side to the lead frame on the ground side, but the overcurrent of the lead frame on the ignition coil side is increased. Since the temperature coefficient of specific resistance is set to be larger than the temperature coefficient of specific resistance of the earth side lead frame, the change in resistance with increasing temperature is larger in the ignition side lead frame than in the earth side lead frame. Therefore, when an overcurrent flows and the temperature of the lead frame rises, the resistance value of the ignition coil side lead frame becomes higher than the resistance value of the ground side lead frame. For this reason, the heat generation amount of the ignition coil side lead frame is larger than the heat generation amount of the ground side lead frame. Therefore, the ignition coil side lead frame connected to the switching element in the abnormal state is melted and cut before the ground side lead frame. Therefore, the overcurrent from the ignition coil is not supplied to the ground side lead frame, and at least the current of the ignition coil connected to the normally functioning switching element can be controlled.

According to the third structure, since the melting point of the ignition coil side lead frame is set lower than the melting point of the ground side lead frame, when the overcurrent flows and the temperature of the lead frame rises, the ground side lead frame is increased. The lead frame on the ignition coil side melts faster than the frame,
The electrical connection is broken. Therefore, the ignition coil side lead frame connected to the switching element in the abnormal state is cut before the ground side lead frame. Therefore, the overcurrent from the ignition coil is not supplied to the ground side lead frame, and at least the current of the ignition coil connected to the normally functioning switching element can be controlled.

According to the fourth structure, at least one of both ends of the lead frame on the ignition coil side is connected by solder, and the solder is used when the current flowing through the lead frame on the ignition coil side exceeds a predetermined value. It is configured to melt and break the electrical connection. Therefore, when an overcurrent flows and the temperature of the lead frame rises, the lead frame on the ignition coil side connected to the abnormal switching element melts. As a result, the overcurrent from the ignition coil is not supplied to the earth side lead frame, and at least the current of the ignition coil connected to the normally functioning switching element can be controlled.

According to the fifth configuration, even if the first current limiting circuit fails, the second current limiting circuit functions to prevent overcurrent. Therefore, it is possible to prevent an overcurrent from flowing through the ignition coil and suppress heat generation of the ignition coil.

The current from the battery flows in the order of the ignition coil, the switching element, the current detection resistor and the ground.
According to the sixth configuration, the resistance value of the conductor electrically connecting the ignition coil and the current detection resistor is set higher than the resistance value of the conductor electrically connecting the current detection resistor and the ground.
Therefore, the amount of heat generated by the conductor that electrically connects the current detection resistor and ground is larger than the amount of heat generated by the conductor that electrically connects the current detection resistor and ground, and the current detection resistor and ground are electrically connected. The conducting conductor is melted faster. Therefore, no current is supplied from the abnormal switching element to the common current detection resistor, and the current flowing through the ignition coil connected to another normal switching element can be controlled.

[0024]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a system configuration diagram showing a so-called 6-cylinder simultaneous ignition type system configuration diagram. The voltage of the battery 11 is applied to one end of the primary coils 17 to 19 of the ignition coils 14 to 16 via the fuse 12 and the switch 13. On the other hand, the output of the sensor group 28 (intake air amount sensor, crank angle sensor, etc.) that detects physical quantities indicating the operating state of the internal combustion engine, such as the intake air amount and the engine speed, is taken in by the control unit 27. The control unit 27 calculates the ignition timing based on the outputs of these sensor groups 28 and outputs a signal to the power module 26. At this time, the signal output from the control unit 27 is about several mA to several tens mA. The power module 26 operates so as to supply the current from the battery 11 to the specific ignition coil (17 to 19) when the control unit 27 outputs a high output. At this time, a current of several A is supplied to the primary coils (17 to 19) of the ignition coils (14 to 16). As will be described later, the current supplied to the primary coils (17 to 19) of the ignition coils (14 to 16) is limited to a predetermined current value or less by the current limiting circuit 64.

In addition, the power module 26 shuts off the current from the battery 11 to the primary coil (17 to 19) of the specific ignition coil (14 to 16) when the control unit 27 outputs low. Operate. When the current supplied so far is interrupted instantaneously, a high voltage is generated in the secondary coil (20-22) of the ignition coil (14-16), and the spark plugs (23a, 23b-25a, 25).
Sparks fly to b).

Next, details of the power module 26 will be described. In FIG. 3, the package terminals 71 to 77 are molded in the outer case 80. Package terminals 71-
One end of 73 is connected to each of the ignition coils 14 to 16 via a connector that can be attached to and detached from the outer case 80.
The other ends of the package terminals 71 to 73 are connected to the power transistors 41 to 43 via the lead frames 51 to 53 (ignition coil side lead frame). In the following, the lead frame is not limited to a flat plate,
It is meant to include all so-called lead wires having a circular cross section, and those having all cross-sectional shapes. The power transistors 41 to 43 are the lead frame 6
It is connected to the hybrid IC substrate 44 via 1 to 63. It is preferable to use lead frames 61 to 63 having relatively small resistance values such as Al, Cu or brass. In addition, instead of the power transistors 41 to 43,
A MOS type FET can be used. Furthermore, it goes without saying that all other semiconductor switching elements can be used.

One end of the package terminals 74 to 76 is connected to the control unit 27 via the lead frames 54 to 56.
, And one end of the package terminal 77 is connected to the ground via the lead frame 57 (ground side lead frame). The other ends of the package terminals 74 to 77 are connected to the hybrid IC board 44.

Further, the connection state of the internal circuit of the power module 26 will be described. In FIG. 4, the package terminals 71 to 73 are welded to one ends of the lead frames 51 to 53 (ignition coil side lead frame). The other ends of the lead frames 51 to 53 are soldered to the ceramic substrate 82 via the welding pad 83. Power transistors 41 to 43 are formed on the ceramic substrate 82 and are electrically connected to the lead frames 51 to 53. Further, the power transistors 41 to 43 are connected to the hybrid IC substrate 44 via lead frames 61 to 63 (made of a material such as Al and Au). The hybrid IC substrate 44 is formed on the metal base 81 via an insulator (not shown). The package terminal 77 is the lead frame 57 (ground side lead frame).
Is welded to one end of. The other end of the lead frame 57 is soldered to the hybrid IC substrate 44 via the welding pad 84. In this way, the hybrid IC substrate 4
4 is electrically connected to the package terminal 77.

Further, the internal circuit configuration of the power module 26 will be described. In FIG. 1, the ignition coils 14-1
6 are connected to the collectors of the power transistors 41 to 43, respectively. The emitters of the power transistors 41 to 43 are connected to the current limiting circuit 64, and further connected to the ground via the lead frame 57. On the other hand, the bases of the power transistors 41 to 43 are resistors 65 to 6 respectively.
It is connected to the lead frames 54 to 56 via 7 and is further connected to the control unit 27.

Here, the relationship between the resistance values R1 to R3 of the lead frames 51 to 53 and the resistance value R4 of the lead frame 57 is R4 <R1 to R3. When using, for example, a Ni wire as the member, R1 to R3≈15 mΩ and R4≈10 mΩ can be set. Further, a Fe—Ni-based material may be used to obtain such a resistance value.

As described above, in order to make the resistance values R1 to R3 of the lead frames 51 to 53 larger than the resistance value R4 of the lead frame 57, the lead frames 51 to 53 are made longer than the lead frame 57. May be. In addition, the thickness of the lead frames 51 to 53 may be smaller than that of the lead frame 57 by making R1 to R3 thinner. Naturally, the lead frame 51 can be changed by changing the material.
It is possible to make the resistance values R1 to R3 of .about.53 larger than the resistance value R4 of the lead frame 57. For example, the lead frames 51 to 53 may be made of Ni or Ni—Fe series, and the lead frame 57 may be made of Al, Cu, brass, or the like.

The operation of the power module 26 will be described. First, in a normal operating state of all the power transistors 41 to 43, when the signal from the control unit 27 is at a low level, the power transistors 41 to 43 are
Since 43 is in the cutoff state, no current (primary current) flows through the primary coils 17 to 19 of the ignition coils 14 to 16. However, if any of the power transistors 41 to 43 is short-circuited for some reason, current continuously flows through the primary coil of the ignition coil regardless of the level of the signal from the control unit 27. At this time, the current is battery 11 → primary coils 17 to 19 → lead frames 51 to 53 → between collector and emitter of power transistors 41 to 43 → lead frames 61a to 63a →
The flow flows in the order of hybrid IC 44 → lead frame 57 → ground. Then, if such abnormal continuous energization continues, the ignition coils 14 to 16 generate heat, and in the worst case, smoking and ignition of the coils occur. To prevent smoke and fire,
It suffices that any one of the wirings of is opened, but if is opened, all other normal circuits do not operate and the engine cannot operate. Also, in general, very short Al and the like, for example, Au wire and Al wire are used, so the amount of heat generated is small even when an overcurrent flows,
Due to this, there is almost no burning out. When is open, current does not flow from the shorted power transistor, smoke and ignition of the coil can be prevented, and a fail-safe mechanism capable of operating the engine can be realized. Here, if the lead terminals 51 to 53 connecting between the package terminals 71 to 73 provided in the package for sealing the circuit of the ignition device and the collectors of the power transistors 41 to 43 are operated like fuses. Cost can be minimized. For that purpose, the package terminals 71 to 73 and the lead frames 51 to
It suffices to make the resistance value of 53 larger than that of the other wirings, and set it to a value that will blow out under specific conditions.

In this way, the power transistors 41 to 4 are
Even if one of the three is short-circuited, an overcurrent flows in the corresponding ignition coil and lead frame, and only the lead frame connected to the short-circuited power transistor (one of the lead frames 51 to 53 is connected). ) Is overheated due to overcurrent and melts due to heat generation. It should be noted that the lead frames 51 to 53 are preferably blown when a current of about 10 A flows through the lead frames 51 to 53.

As a result, the power transistors (41-4
3) short circuit->overcurrent-> lead frame (one of 51-53) is blown-> overcurrent stop-> ignition continues with another power transistor. Even if the power transistor is short-circuited due to an element defect or the like, the lead frame on the collector side of the short-circuited power transistor is immediately blown, and overcurrent does not flow to the ignition coils 14 to 16 and the hybrid IC substrate 44. By allowing the remaining cylinders to ignite normally, the ignition operation becomes possible. Further, since the continuous overcurrent is prevented from flowing through the ignition coil, it is possible to prevent smoking and ignition of the ignition coil.

Further, details of the current limiting circuit 64 will be described. In FIG. 5, the emitter of the power transistor 41, the emitter of the power transistor 42, and the emitter of the power transistor 43 are all connected to one end of the current limiting resistor 85. The other end of the current limiting resistor 85 is connected to the ground. A resistor 86 and a resistor 87 are connected in parallel with the current detection resistor 85 between the emitters of the power transistors 41 to 43 and the ground. The base of the power transistor 41, the base of the power transistor 42, and the base of the power transistor 43 are all connected to the collector of the transistor 88. The emitter of transistor 88 is connected to ground. Further, the base of the transistor 88 is connected to the connection point of the resistors 89 and 89. The bases of the power transistors 41 to 43 are also connected to the control unit 27, respectively.

The operation of the current limiting circuit 64 will be described. When the current Ib from the control unit 27 flows, the transistor 42 (transistors 41 and 43) becomes conductive. When the transistor 42 (transistors 41, 43) becomes conductive, the transistor 42 (transistor 4
1, 43) collector-emitter voltage gradually rises. This voltage is detected by the current detection resistor 85,
Further, the voltage is divided by the resistors 86 and 87. When this value exceeds the threshold level Vb (about 0.7 V), the transistor 88 becomes conductive and connects the base of the power transistor 42 and the ground. As a result, the transistor 42 is turned off.

Since the emitters of the power transistors 41 to 43 are connected to the commonly used current limiting resistor 85, any current of the power transistors 41 to 43 exceeds the threshold level Vb, When the transistor 88 is turned on, the power transistor 4
The bases 1 to 43 are all connected to the ground. That is, if the current of any of the power transistors 41 to 43 becomes a current equal to or higher than a certain value, all of the power transistors 41 to 43 operate so as to be in the cutoff state.

For example, when any one of the power transistors 41 to 43 is short-circuited and is always in the conductive state, a current more than a predetermined value always flows through the current detection resistor 85, so that the current limiting circuit 64 always outputs the power. It operates so that all of the transistors 41 to 43 are turned off. In such a state, no current is supplied to all of the ignition coils 14 to 16, and it becomes impossible to ignite the air-fuel mixture supplied to the internal combustion engine, and the internal combustion engine must stop its operation completely. I don't get it.

However, as described above, in the present embodiment, when an overcurrent flows through the power transistors 41 to 43, the power transistors (41 to 43).
Corresponding to the lead frame (lead frames 51 to 53
Either) burns out. Therefore, the shorted power transistors (41 to 43) are connected to the current detection resistor 8
Since no current is supplied to 5, the short circuit of one power transistor (41 to 43) does not hinder the operation of the other normal power transistors (41 to 43).

As described above, according to the present embodiment, even if the power transistor (any one of 41 to 43) is short-circuited, the lead frame (which is provided in the package that seals the circuit of the power module 26 ( Lead frame 51
~ 53) and power transistors (41-43)
Since the connection between any of the collectors) is forcibly cut off by fusing, smoke and ignition of the ignition coil can be prevented, and even if the vehicle is out of order as if a second current limiting circuit was provided, Fail-safe running is possible, and it can be provided at low cost.

In this embodiment, the ground side lead frame 57 is used to connect the emitters of the power transistors 41 to 43 to the ground. Instead of this, the emitters of the power transistors 41 to 43 are connected to the (current limiting circuit). 6
It may be connected to the metal base 81 (via 4). This current limiting circuit 64 for grounding and the metal base 8
The connection of 1 uses an aluminum wire, and these can be connected by welding. In this way, the metal base 81
According to the grounding method using, the emitters of the power transistors 41 to 43 can be grounded by simply welding, which simplifies the work and further simplifies the overall configuration of the power module. Next, another embodiment will be described with reference to FIG. In this embodiment, the lead frame 57 (FIG. 6B) is replaced with the lead frames 51-53.
This is configured by connecting two exactly the same thing as in FIG. 6A in parallel.

Further, another embodiment will be described with reference to FIG. In this embodiment, the collector-emitter current of the power transistor 41 is controlled by the current limiting circuit 91. Further, the collector-emitter currents of the power transistor 42 and the power transistor 43 are controlled by the current limiting circuit 92.
(Installed separately from the current limiting circuit 91). In this way, the current flowing through the power transistors 41 to 43 is controlled by the two current limiting circuits (current limiting circuits 91, 9
Since it is controlled by 2), even if one of the current limiting circuits is in an abnormal state, the other current limiting circuit operates normally.

Further, another embodiment will be described with reference to FIG. In this embodiment, the collector-emitter current of the power transistor 41 is controlled by the current limiting circuit 93, the collector-emitter current of the power transistor 42 is controlled by the current limiting circuit 94, and the collector-emitter current of the power transistor 43 is controlled by the current limiting circuit 95. Have control. In this way, the currents flowing through the power transistors 41 to 43 are controlled by the current limiting circuits 93 to 95, respectively. Therefore, even if one of the current limiting circuits 93 to 95 is in an abnormal state, the other current limiting circuits Works fine.

Further, another embodiment will be described with reference to FIG. In this embodiment, four ignition coils 14, 15, 1
A so-called 8-cylinder simultaneous ignition system in which two spark plugs are connected to each of 6 and 99 is shown. The ignition coils 14, 15, 16 and 99 are connected to the power transistors 41, 42, 43 and 97 via lead frames 51, 52, 53 and 98, respectively. Further, the power transistors 41, 42, 43 and 97 are connected to the control unit 27 via the lead frames 54, 55, 56 and 96. The other parts are the same as those in the above-described embodiment and will not be described.

Further, another embodiment will be described with reference to FIG. In this embodiment, four ignition coils 14, 15,
A so-called 4-cylinder independent ignition system in which one spark plug is connected to each of 16 and 99 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, the power transistors 41 and 4 are
The current flowing in 2 is controlled by the current limiting circuit 100,
Further, the current flowing in the power transistors 43 and 97 is controlled by the current limiting circuit 101. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, four ignition coils 14, 15,
A so-called 4-cylinder independent ignition system in which one spark plug is connected to each of 16 and 99 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, the power transistors 41, 4
The currents flowing through 2, 43 and 97 are controlled by current limiting circuits 102, 103, 104 and 105, respectively. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, four ignition coils 14, 15,
A so-called 4-cylinder independent ignition system in which one spark plug is connected to each of 16 and 99 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, six ignition coils 14, 15,
A so-called 12-cylinder simultaneous ignition system in which two spark plugs are connected to each of 16, 99, 116 and 117 is shown. Ignition coil 14, 15, 16,
99, 116 and 117 are lead frames 5 respectively.
Power transistors 41, 42, 43, 97, 112 and 1 via 1, 52, 53, 98, 114 and 115.
It is connected to 13. Furthermore, power transistor 4
1, 42, 43, 97, 112 and 113 are connected to the control unit 27 via lead frames 54, 55, 56, 96, 110 and 111. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, six ignition coils 14, 15,
A so-called 6-cylinder independent ignition system in which one spark plug is connected to each of 16, 99, 116 and 117 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, the power transistors 41, 42
And 43 are controlled by the current limiting circuit 120, and the power transistors 97, 112 and 11 are controlled.
The current flowing in the circuit 3 is controlled by the current limiting circuit 121. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, six ignition coils 14, 15,
A so-called 6-cylinder independent ignition system in which one spark plug is connected to each of 16, 99, 116 and 117 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, the power transistors 41 and 4 are
2 is controlled by the current limiting circuit 122,
The current flowing through the power transistors 43 and 97 is controlled by the current limiting circuit 123,
A current limiting circuit 124 controls the currents flowing in 2 and 113. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, six ignition coils 14, 15,
A so-called 6-cylinder independent ignition system in which one spark plug is connected to each of 16, 99, 116 and 117 is shown. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, the power transistors 41, 4
2, 43, 97, 112 and 113, the currents flowing through the current limiting circuits 125, 126, 127, 128 and 1 respectively.
It is controlled by 29 and 130. The other parts are similar to those of the embodiment shown in FIG.

Further, another embodiment will be described with reference to FIG. In this embodiment, six ignition coils 14, 15,
A so-called 6-cylinder independent ignition system in which one spark plug is connected to each of 16, 99, 116 and 117 is shown. The other parts are similar to those of the embodiment shown in FIG.

Here, in the embodiment shown in FIGS. 10, 12, and 14, an 8-cylinder independent ignition system in which two ignition plugs are connected to each ignition coil may be adopted. Further, in the embodiment shown in FIGS. 16, 18, 20, and 22, it is also possible to adopt a 12-cylinder simultaneous ignition system in which two ignition plugs are connected to each ignition coil.

As described above, in each of the embodiments shown in FIGS. 1 to 22, the resistance value of the lead frames 51 to 53 (ignition side lead frame) is larger than the resistance value of the lead frame 57 (ground side lead frame). By doing
Measures were taken when the power transistors 41 to 43 were short-circuited. In such an embodiment, the following configuration may be adopted. In addition, in the following description, FIG.
The description of the same parts as those in each of the embodiments shown in 2 will be omitted.
Therefore, in principle, the parts not described below are shown in FIG.
22 to 22 are the same as those of the embodiments shown in FIG.

First, the ignition coil side lead frames 51 to 51
By making the melting point of 53 lower than that of the earth side lead frame 57, it is possible to obtain substantially the same effect as that of the above-mentioned embodiment. For example, an aluminum lead frame (melting point; 660.4 degrees Celsius) is used as the ignition coil side lead frame (51 to 53), and a copper lead frame (melting point; 1084.5) is used as the earth side lead frame 57.
It is good to use degrees Celsius).

Further, the ignition coil side lead frame 51
Even if the connections of ~ 53 are soldered, it is possible to obtain substantially the same effect as that of the above-described embodiment. That is, the package terminals 71 to 73 and the ignition coil side lead frames 51 to 53 are eutectic solder (component: tin 40% lead 6
0%, melting point; 183 degrees Celsius), or the ignition coil side lead frames 51 to 53 and the ceramic substrate 82 may be connected using eutectic solder. In this case, the earth side lead frame 57 is connected by using high temperature solder (component: tin 10% 90% lead, melting point 320 ° C.) or by welding. When the power transistors 41 to 43 are short-circuited and the conduction state continues, the current flowing through the ignition side lead frame (corresponding one of the lead frames 51 to 53) and the ground side lead frame 57 becomes large and heat is generated. Although the temperatures of the ignition side lead frame (any one of the lead frames 51 to 53 corresponding to the short-circuited power transistor) and the ground side lead frame 57 rise, the ignition coil side lead frame (51 to 53) is eutectic solder. Are connected by a relatively low temperature (183
When the temperature reaches celsius, the eutectic solder melts first and the ignition coils 14 to 16 and the power transistors 41 to 43 (shorted) corresponding to the shorted power transistors are disconnected. At this time, it is more preferable that a spring force is generated in the ignition coil side lead frames 51 to 53. With this configuration, when the eutectic solder melts, the ignition coil side lead frame 51
~ 53 is elastically deformed, the ignition coil side lead frame 5
The release of the connection by 1 to 53 becomes more reliable.

Further, the ignition coil side lead frame 51
By making the temperature coefficient of the specific resistances of to 53 larger than the temperature coefficient of the specific resistance of the earth side lead frame 57, it is possible to obtain substantially the same effect as the above-mentioned embodiment.
For example, it is preferable to use the ignition coil side lead frames 51 to 53 having the characteristics shown in FIG. 23A and the ground side lead frame 57 having the characteristics shown in FIG. 23B. Power transistors 41-4
When 3 is short-circuited and the open state continues, the current flowing through the ignition side lead frame (one of the lead frames 51 to 53 corresponding to the short-circuited power transistor) and the ground side lead frame 57 becomes large and heat is generated.
Due to this heat generation, the resistance values of both the ignition coil side lead frame (one of the lead frames 51 to 53) and the ground side lead frame 57 increase, but the temperature of the specific resistance of the ignition coil side lead frames 51 to 53 increases. Since the coefficient is larger than the temperature coefficient of the resistivity of the earth side lead frame 57, the ignition coil side lead frame (51-5
In the case of 3), the resistance value sharply increases, and thereby the amount of heat generation also sharply increases. Due to such a synergistic effect, the temperature of the ignition coil side lead frame (one of the lead frames 51 to 53) rapidly rises, and the ignition coil side lead frame (corresponding to the shorted power transistor) becomes the ground side lead frame. It is blown out before 57.

[0063]

As described above, according to the inventions according to the first to fourth structures, even if one of the plurality of switching elements is fixed in the conductive state, the other switching elements functioning normally. It is possible to control the current flowing through the ignition coil connected to the. According to the fifth aspect of the present invention, even if the current limiting circuit does not function sufficiently, it is possible to prevent an overcurrent from flowing through the ignition coil and suppress the heat generation of the ignition coil. Further, according to the sixth configuration of the invention, even if the current flowing through one of the switching elements connected to the common current detection resistor becomes a predetermined value or more, the current flows through the ignition coil connected to another switching element. It becomes possible to control the current.

[Brief description of 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 structure of a power module.

FIG. 4 is a diagram showing details of connections of circuits in the power module.

FIG. 5 is a diagram showing details of a current limiting circuit.

FIG. 6 is a diagram showing an embodiment having a characteristic connection of lead frames.

FIG. 7 is a diagram showing an embodiment in which two current detection units are provided in a 6-cylinder simultaneous ignition system.

FIG. 8 is a diagram showing an embodiment in which three current detection units are provided in a 6-cylinder simultaneous ignition system.

FIG. 9 is a diagram showing an embodiment in which one current detection unit is provided in an 8-cylinder simultaneous ignition system.

FIG. 10 is a diagram showing an embodiment in which one current detection unit is provided in a 4-cylinder independent ignition system.

FIG. 11 is a diagram showing an embodiment in which two current detection units are provided in an 8-cylinder simultaneous ignition system.

FIG. 12 is a diagram showing an embodiment in which two current detection units are provided in a 4-cylinder independent ignition system.

FIG. 13 is a diagram showing an embodiment in which four current detection units are provided in an 8-cylinder simultaneous ignition system.

FIG. 14 is a diagram showing an embodiment in which four current detection units are provided in a four-cylinder independent ignition system.

FIG. 15 is a diagram showing an embodiment in which one current detection unit is provided in a 12-cylinder simultaneous ignition system.

FIG. 16 is a diagram showing an embodiment in which one current detection unit is provided in a 6-cylinder independent ignition system.

FIG. 17 is a diagram showing an embodiment in which two current detection units are provided in a 12-cylinder simultaneous ignition system.

FIG. 18 is a diagram showing an embodiment in which two current detection units are provided in a 6-cylinder independent ignition system.

FIG. 19 is a diagram showing an embodiment in which three current detection units are provided in a 12-cylinder simultaneous ignition system.

FIG. 20 is a diagram showing an embodiment in which three current detection units are provided in a 6-cylinder independent ignition system.

FIG. 21 is a diagram showing an embodiment in which six current detectors are provided in a 12-cylinder simultaneous ignition system.

FIG. 22 is a diagram showing an embodiment in which six current detection units are provided in a 6-cylinder independent ignition system.

FIG. 23 is a diagram showing changes in resistance with respect to temperature of the ignition side lead frame and the ground side lead frame.

[Explanation of symbols]

14 to 16 ... Ignition coil, 41 to 43 ... Power transistors, 51 to 53 ... Ignition coil side lead frame, 57
… Earth side lead frame, 64… Current limiting circuit, 85
… Current detection resistor.

Claims (21)

[Claims] 1. A plurality of switching elements for individually conducting and interrupting currents flowing through a plurality of ignition coils, and a plurality of first lead frames for individually supplying currents of the plurality of switching elements to the plurality of ignition coils, respectively. , A single second lead frame for dropping a current of at least two or more switching elements among the plurality of switching elements to a common potential, the resistance value of the first lead frame is An electronic distributor for an internal combustion engine, which is set to have a resistance value higher than that of the second lead frame. 2. The electronic distributor for an internal combustion engine according to claim 1, wherein the first lead frame is longer than the second lead frame. 3. The electronic distributor for an internal combustion engine according to claim 1, wherein the first lead frame is made thinner than the second lead frame. 4. The electronic power distributor for an internal combustion engine according to claim 1, wherein the first lead frame and the second lead frame are made of different materials. 5. The internal combustion engine according to claim 4, wherein the first lead frame is made of a nickel- or iron-nickel-based material, and the second lead frame is made of aluminum, copper, or brass. Electronic power distribution equipment. 6. The electronic distributor for an internal combustion engine according to claim 1, wherein the number of second lead frames formed is greater than the number of first lead frames formed. 7. The electronic distributor for an internal combustion engine according to claim 1, wherein the switching element is arranged on a metal base, and the second lead frame is connected to the metal base. 8. A plurality of switching elements for individually conducting and interrupting currents flowing through a plurality of ignition coils, and a plurality of first lead frames for individually supplying currents of the plurality of switching elements to the plurality of ignition coils, respectively. And a single second lead frame for dropping a current of at least two switching elements among the plurality of switching elements to a common potential, the specific electrical resistivity of the first lead frame. Is set to be larger than the temperature coefficient of the specific resistance of the second lead frame. 9. A plurality of switching elements for individually conducting and interrupting currents flowing through a plurality of ignition coils, and a plurality of first lead frames for individually flowing currents of the plurality of switching elements through the plurality of ignition coils, respectively. And a single second lead frame for dropping a current of at least two switching elements among the plurality of switching elements to a common potential, in the electronic distributor for an internal combustion engine, the melting point of the first lead frame is An electronic distributor for an internal combustion engine, wherein the melting point is set lower than the melting point of the second lead frame. 10. A plurality of switching elements for individually conducting and interrupting currents flowing through a plurality of ignition coils, and a plurality of first lead frames for separately flowing currents of the plurality of switching elements through the plurality of ignition coils, respectively. , A single second lead frame for dropping a current of at least two switching elements among the plurality of switching elements to a common potential, in an electronic distributor for an internal combustion engine, wherein both ends of the first lead frame are connected. At least one of them is connected by solder, and the solder is configured to melt when the current flowing through the first lead frame becomes a predetermined value or more to break the electrical connection. Electronic distributor for engines. 11. The electronic distributor for an internal combustion engine according to claim 10, wherein the first lead frame is configured to be elastically deformed after the solder is melted. 12. A plurality of switching elements for individually conducting and blocking currents flowing through a plurality of ignition coils, and a current flowing through the switching element when the current flowing through the switching element becomes larger than a first predetermined value. An electronic distributor for an internal combustion engine, comprising: a first current limiting unit that limits a current flowing through the switching element when a current larger than a second predetermined value flows through the switching element. And a second predetermined value set to be larger than the first predetermined value. 13. A plurality of switching elements for individually conducting and interrupting currents flowing through a plurality of ignition coils, a common current detection resistor into which a current flowing through the plurality of switching elements flows, and a current flowing through the current detection resistor. In an electronic distributor for an internal combustion engine, having a current limiting circuit that simultaneously interrupts currents flowing through the plurality of switching elements when a predetermined value is exceeded, a conductor that electrically connects the ignition coil and the current detection resistor. Is set to be higher than the resistance value of a conductor that electrically connects the current detection resistor and the ground, the electronic distributor for an internal combustion engine. 14. An internal combustion engine having a plurality of switching elements for individually conducting and interrupting a current flowing through a plurality of ignition coils, and a common potential at which a current of at least two switching elements among the plurality of switching elements flows. In the engine electronic distributor, the resistance value of the conductor connecting the ignition coil and the switching element is the same as the current flowing through the plurality of switching elements among the conductors connecting the plurality of switching elements and the common potential. An electronic distributor for an internal combustion engine, which is set to have a resistance value higher than that of a flowing conductor. 15. A current flowing from a battery to a plurality of ignition coils is separately conducted and cut off by a plurality of switching elements, the currents from the plurality of switching elements are coupled by a coupling point, and the current at the coupling point is grounded. In a distributor for an internal combustion engine that is grounded to, a current limiting unit that limits a current when any of the plurality of switching elements is in an unblockable state, and the current limiting unit is the battery To the above-mentioned connecting point. 16. A current flowing from a battery to a plurality of ignition coils is separately conducted and cut off by a plurality of switching elements, the currents from the plurality of switching elements are coupled by a coupling point, and the current at the coupling point is grounded. In a distributor for an internal combustion engine grounded to, when any of the plurality of switching elements is in a non-interruptible state, among the conductors flowing in the non-interruptible switching element, A distributor for an internal combustion engine, which is configured to cut off any part of the conductor from the battery to the connection point. 17. A switching element for connecting and disconnecting a current flowing through an ignition coil, and a first element for limiting a current flowing through the switching element when the current flowing through the switching element exceeds a first predetermined value. An ignition device for an internal combustion engine having current limiting means, comprising second current limiting means for limiting a current flowing through the switching element when a current larger than a second predetermined value flows through the switching element. Further, the ignition device for an internal combustion engine, wherein the second predetermined value is set to be larger than the first predetermined value. 18. An electronic device for load control, comprising: first current limiting means for limiting the current flowing through the electric load when the current flowing through the electric load becomes larger than a first predetermined value. In the above, there is provided a second current limiting means for limiting a current when a current larger than a second predetermined value flows into the electrical load, and further, the second predetermined value is set to the first value.
The load control electronic device is set to be larger than a predetermined value of. 19. A plurality of switching elements separately conducts and blocks currents flowing from a first potential to a plurality of electric loads, and currents from the plurality of switching elements are coupled by a coupling point, and further coupled. In a load control electronic device that causes a current at a point to flow to a second potential, when any of the plurality of switching elements is in an unblockable state, the switching element is in an unblockable state An electronic device for load control, comprising: current limiting means for limiting a current flowing through the current limiting means, the current limiting means being arranged between the first potential and the coupling point. 20. A plurality of switching elements separately conducts and cuts off a current flowing from a first potential to a plurality of electric loads, and currents from the plurality of switching elements are coupled by a coupling point, and further coupled. In a load control electronic device that causes a current at a point to flow to a second potential, when any of the plurality of switching elements is in an unblockable state, the current flows to the unblockable switching element. The load control electronic device is configured to cut off any part of the conductor from the first potential to the coupling point, among the conductors that were passing the current. 21. A plurality of switching elements for individually conducting and cutting off currents flowing through a plurality of ignition coils, a control unit for controlling a switching state of the plurality of switching elements, and a current for the plurality of switching elements. Internal combustion having a plurality of first lead frames separately supplied to a plurality of ignition coils, and a single second lead frame for dropping a current of at least two or more switching elements among the plurality of switching elements to a common potential The ignition timing control device for an internal combustion engine, wherein the resistance value of the first lead frame is set higher than the resistance value of the second lead frame.