JPH09284981A - Automotive power supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a layer short circuit in an automotive wiring and prevent a smoking or firing accident. SOLUTION: A power supply unit 10 is provided between a battery B and respective load units (50, etc.) such as a light control unit 50, etc. The power supply unit 10 is connected to the respective load units (50, etc.) through a multiplex signal line 80 and a consumption current Ia which is calculated in accordance with the operation states which are transmitted from the respective load units (50, etc.) through the multiplex signal line 80 and a supply current Ib from the battery B are monitored. If it is detected that the supply current Ib is excessive, the current supply to the load unit (50, etc.) from the battery B is cut off, so that a phenomenon such as a layer short circuit whose short- circuit state lasts only a very short time can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electric power supply to electric components in an automobile, and more particularly to detecting a short circuit or disconnection that occurs when electric power is supplied to electric components to cut off electric power supply to a load. The present invention relates to an automobile power supply device.

[0002]

2. Description of the Related Art Many electrical components, such as wipers, power windows, door locks, lights, electronic control units ...
-In a recent automobile equipped with etc., a large number of electric wires (wire harnesses) connecting the electric components and the battery are stretched around the vehicle body. As a result, the electric wires stretched around the vehicle body may be damaged due to vibrations during traveling, the coating may be damaged, or the conductor inside may be broken. In particular, if the coating is damaged, the conductor inside and the body (ground potential) may come into contact with each other, causing a short-circuit current to flow and causing smoking.

In order to prevent such a phenomenon, conventionally, as shown in FIG. 4, a fusible link 1 and a fuse 2 are provided between a battery B and a load such as an electrical component, and the fusible link 1 and the fuse 2 are blown when a short circuit occurs. The short-circuit current was cut off.

[0004]

However, in the fusible link and the fuse as described above, the fusible body forming the fusible link or the fuse has a heat capacity so that a certain time elapses until the fusing temperature is reached and the fusing occurs. In this way, malfunction is not caused by the rush current or spike current of the load.

Therefore, for example, when a phenomenon such as a rare short circuit occurs in which a damaged portion of the electric wire makes contact with the body a large number of times for an extremely short time, the fusible link or the fuse does not melt and the electric wire emits smoke. there's a possibility that.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to detect not only a short circuit but also a rare short circuit as described above to prevent smoke from occurring and also to detect disconnection.

[0007]

In order to solve the above-mentioned problems, according to the present invention, the operating conditions of respective load units such as a wiper unit, a power window unit, a door lock unit, a light unit, etc., which are connected to an automobile battery, The supply current from the battery is constantly monitored, the consumption current required by the load unit is calculated from the operating status by the monitoring, the calculated consumption current is compared with the supply current from the battery, and the required consumption current is calculated. When it detects that the supply current is excessive or insufficient, it adopts a configuration that shuts off the power supply from the battery to the load unit. Always compare the current flowing to the load unit with the current required by the load unit. By monitoring or not or have, it was to be able to cut off the power supply short circuit or by detecting the disconnection to the load unit from the battery (claim 1).

At this time, the automobile power supply device has a power supply unit connected to each load unit by a multiple signal line, and the power supply unit is output from each load unit via the signal line. Therefore, the required current consumption is calculated based on the operating condition (Claim 2).

Further, at this time, a configuration is adopted in which the calculated current consumption of the load unit and supply current are compared with each other after a certain period of time has elapsed after detecting the operating state of the load unit. Even in the case of a lamp load, a measurement error due to the rush current is prevented (claim 3).

In this case, each load unit has a memory for storing a current consumption value of each load unit, and each load unit needs a value obtained by detecting a current value flowing in each load unit in the memory and adding a predetermined margin. It is also possible to employ a configuration in which the consumption current is stored as the consumption current and the comparison with the supply current is performed based on the stored value (claim 4).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An automobile power supply device according to the present invention will be described below with reference to the drawings.

As shown in the block diagram of FIG. 1, the power supply device for an automobile according to the present embodiment has a power supply unit 10 connected to a battery B, and the power supply unit 10.
A plurality of control units 20, 30, 40, 5 connected to each other via a current supply line 70 and a multiple signal line 80.
It is composed of 0 and 60.

As shown in FIG. 2, the power supply unit 10 comprises a microcomputer 11, a current detection circuit 12, a shunt resistor Rs, a power relay RL, a relay driver circuit 13, and transmission / reception interface circuits 14 and 15, and a battery. Power input Pi connected to B
n, a power output Pout connected to the current supply line 70,
An external connection port PO for connecting to the bus-type multiple signal line 80 is provided.

The power input Pin is a power relay RL.
Is connected to one end of a series circuit in which a shunt resistor Rs is connected in series, and the other end of the series circuit is connected to the power output Pout, and each control unit 20, 30, 40, 50 connected to the power output Pout. The current supply to 60 can be turned on / off by the power relay RL.

The shunt resistor Rs is a resistor for detecting a current having a small resistance value, and both ends thereof are connected to the inverting and non-inverting inputs of the current detecting circuit 12 using an operational amplifier as shown in FIG. Further, the operation amplifier output is connected to the A / D conversion input ADin of the microcomputer 11, and the microcomputer 11 is connected to the shunt resistor Rs.
A / D conversion is performed on the voltage drop at both ends of the battery, and the current value supplied from the battery B can be constantly read.

In this embodiment, the shunt resistance Rs is used to detect the current. However, the method is not limited to this method, and other than this, instead of the shunt resistance Rs, for example, a Hall element is provided in the current path. A magnetic sensor for current detection such as the above may be attached to detect the current.

In this embodiment, the microcomputer 11 is connected to the current detection circuit 12 as described above.
/ D conversion circuit, parallel port P for input / output with external circuit
R, a communication serial port SR, a one-chip microcomputer provided with a memory and the like in a package, the switch 16 and the relay driver circuit 13 are connected to the input / output parallel port PR, and the communication serial port SR
The transmitting and receiving interface circuits 14 and 15 are connected to the.

The switch 16 is an A / D conversion input AD.
A setting switch for storing the current value input to in in the microcomputer 11, which will be described later.

The relay driver circuit 13 is connected to the power supply relay RL, and the microcomputer 11 drives the relay RL so that the current supply from the battery B to the current supply line 70 can be turned ON / OFF. .

The transmitting / receiving interfaces 14 and 15 are
Each control unit 20, 30, 40, 5 is connected to an external connection port PO connected to the multiple signal line 80.
Data can be sent and received with 0, 60.

Control units 20, 30, 40,
50 and 60 are, for example, the wiper control unit 2
0, power window control unit 30, door lock control unit 40, light control unit 50, ABS unit 60, etc., which are provided for each electric component.
30, 40, 50 and 60 are connected in parallel to the current supply line 70 and the multiple signal line 80 (bus system).

Each control unit 20, 30, 4
Reference numerals 0, 50, and 60 denote a one-chip microcomputer 51 and drive relays (hereinafter, lighting relays) r1 and r, respectively, as shown in the light control unit 50 of FIG.
2, relay drive circuits 52 and 53, transmission / reception interface circuits 54 and 55, switch input circuit 56, and the like, and includes a power input PW and an external connection port PO.

That is, in the light control unit 50 of FIG. 3, the lighting relays r1 and r2 connected between the current supply line 70 and the high beam lamp Lh and the low beam lamp Lo of the headlight are relay drive circuits 52 and 5.
3 is connected to the output port of the one-chip microcomputer 51, and the one-chip microcomputer 51 is connected to the lighting relay r.
By operating 1 and r2, the headlight can be switched between high and low, and ON / OFF can be controlled.

Further, for these controls, for example, by providing three inputs (high, low, and passing) as the switch input circuit 56 in the one-chip microcomputer 51 and connecting with the light switch 57 in the driver's seat, either When the input becomes the "L" level, the state is read and the processing according to it is performed. That is, high input H
When is selected, the lighting relay r2 is operated to light the high beam lamp Lh, and when the low input L is selected, the lighting relay r1 is operated to light the low beam lamp Lo. When the passing input P is selected, the lighting relays r1 and r2 are turned on and off to cause the lamps Lh and Lo to blink.

Similarly, the drive relays of the other control units 20, 30, 40 and 60 shown in FIG. 1 are connected to wiper motors, power window motors, door lock motors, ABS actuators, etc. The one-chip microcomputer 51 can control ON / OFF of the actuator.

Further, each control unit 20, 3
The one-chip microcomputer 51 of 0, 40, 60 is also provided with a switch input circuit and is connected to the operation switch of the driver's seat. For example, in the wiper control unit 20, one input is three inputs (high, low, mist). )
Is provided and connected to the wiper actuation switch on the driver's seat, the switch state of the wiper actuation switch can be read and processing can be performed accordingly. The same applies to the power window control unit (up, down) ..., And the door lock control unit (lock, unlock).

Further, each control unit 20, 3
The one-chip microcomputer 51 of 0, 40, 50, 60 is connected to the external connection port PO connected to the multiple signal line 80 via the transmission / reception interface circuits 54, 55, and each control unit 20, 30, 40. , 5
0, 60 and the power supply unit 10 are, for example, CSMA /
CD (Carrier Sense Access w)
A network is formed by including a LAN protocol such as the it Collision Detection method.

That is, different addresses are given to the power supply unit 10 and the control units 20, 30, 40, 50 and 60, respectively, and the operating conditions of the control units 20, 30, 40, 50 and 60, for example, light control. The unit 50 is configured to be able to transmit data indicating operating states such as high, low, and passing of headlights to the power supply unit 10 via the multiplex signal line 80.

Then, in this way, one multiple signal line 80
With a large number of control units 20, 30, 40, 5
The information of 0 and 60 is transmitted so that the increase in the number of wirings is suppressed.

By the way, the CSMA / CD system will be briefly described here. The transmission procedure is as follows: (1) A terminal that transmits data monitors a bus that is a transmission medium and other terminals do not transmit. Make sure that. (2) When the bus is not used, the data is transmitted after waiting for the minimum interval between frames. At this time, the other terminal checks the bus, fetches the data if it is addressed to this terminal, and discards the data addressed to the other terminal. (3) The transmitting terminal constantly monitors the bus during the data transmission period to check for the occurrence of data collision. (4) When data collides, a jam signal is sent to stop the transmission, wait for a fixed time determined by a random number, and then transmit the data again.

That is, each terminal can perform data transmission through one transmission line while preventing data collision.

This embodiment is configured as described above, and its operation will be described next.

In this automobile power supply device, a load is stored in the memory of the microprocessor 11 of the power supply unit 10, for example, each control unit 2 as shown below.
Current consumption Ia required by 0, 30, 40, 50, 60
Data table of Using the data, each control unit 20, 3
0, 40, 50, 60, that is, the multiple signal lines 80 from the load units such as the wiper control unit 20, the power window control unit 30, the door lock control unit 40, the light control unit 50, the ABS control unit 60. The consumption current Ia required by the operating control units 20, 30, 40, 50, 60 is calculated based on the operation state transmitted via the battery B flowing through the calculated consumption current Ia and the shunt resistance Rs. The current supply from the battery B to the control units 20, 30, 40, 50, 60 is cut off when it is detected that the supply current Ib is excessive or insufficient.

Hereinafter, the processing will be described in order from the start of the vehicle (at the time of initial).

When the key is OFF at the time of starting, the power supply unit is also OFF and the power relay RL is OPEN.

When the key is turned on, the power supply unit 1
0 is supplied with current and is in an operating state. for that reason,
The power supply unit 10 connects each control unit 2 to the multiple signal line 80 according to the CSMA / CD protocol.
It is monitored whether there is any transmission from 0, 30, 40, 50, 60 to inform the operating status. At this time, the power relay RL is still OFF, and the current flowing through the shunt resistor Rs is 0. Therefore, in the current supply line 70,
No electric current is supplied to each control unit 20, 3
The consumption current Ia of 0, 40, 50 and 60 is also 0.

Therefore, each control unit 2
Since no data is transmitted from 0, 30, 40, 50, 60, 90, the current consumption Ia calculated by the power supply unit 10 using the data table is also 0.

At this time, the power supply unit 10 detects the current flowing through the shunt resistor Rs by the current detection circuit 12, A / D-converts the detected value, and the battery B
The supply current Ib is detected, but as described above, since the current flowing through the shunt resistor Rs is 0, the detected supply current Ib is also 0. Therefore, Ia = Ib,
Since Ia> Ib is not satisfied, the power supply unit 10 turns on the power relay RL to turn on the battery B and the current supply line 7.
0 is connected to each control unit 20, 30, 4
Supply current to 0, 50 and 60.

Incidentally, at this time, if Ia> Ib, it is determined that the power supply unit 10 is short-circuited, and the power supply unit 10 turns off the power supply relay RL to cut off the supply of current.

When the current is supplied in this manner, each control unit 20, 30, 40, 50, 60 enters the standby state and receives the switch input.

In this state, for example, if the light switch 57 in the driver's seat is set to the Lo position, the one-chip microcomputer 51 of the light control unit 50 reads that it has been set to the Lo position,
The lighting relay r1 is activated to light the low beam lamp Lo. At the same time, data indicating that the low beam lamp Lo is turned on is transmitted to the multiple signal line 80 via the transmission interface circuit 54. At this time, the one-chip microcomputer 51 of the write control unit 50 monitors the multiple signal line 80 by the receiving interface circuit 55 according to the protocol, and the other control unit 2
After confirming that no data is transmitted from 0, 30, 40, 60, the data is transmitted.

Thus, the light control unit 50
When data is transmitted from the multiple signal line 80 to the multiple signal line 80, the data is received by the power supply unit 10 that monitors the multiple signal line 80, and the data corresponding to the controller 50 is consumed from the data table based on the received data. The current Ia is read.

On the other hand, at this time, the power supply unit 10
Is an A / D conversion input ADi of the microcomputer 11.
The detection output from the current detection circuit 12 input to n constantly detects the supply current Ib actually flowing through the current supply line 70, and compares the detected supply current Ib with the read consumption current Ia. . Then, as a result of the comparison, for example, when Ia is 5 A and Ib is 4 A, Ia (necessary consumption current)> Ib (actual supply current)
In the case of, the supply current Ib is lower than the consumption current Ia, and there is no risk of short circuit or rare short circuit.
The current supply is continued while L is turned on.

Conversely, when Ia = 5A and Ib = 6A, and Ia <Ib, the supply current Ib is the consumed current Ia.
If it exceeds the above, it is considered that an abnormal current is flowing due to a short circuit, a rare short circuit, or the like. Therefore, the power supply unit 10 turns off the power relay RL to cut off the current supply.

When Ia >> Ib and the supply current Ib is less than the consumption current Ia, such as Ia = 5A and Ib = 0.1A, it is considered that the current has stopped due to disconnection. Therefore, the power supply unit 10 turns off the current relay RL to cut off the current supply.

As described above, in this vehicle power supply device, the current supplied from the battery B is constantly monitored, and the supply current Ib is more than the consumption current Ia required by the control units 20, 30, 40, 50 and 60. When it is detected that the battery is excessive or insufficient, the current supply from the battery B is cut off.

On the other hand, for example, the light switch 57 in the driver's seat
When the operating control unit 50 is set to the OFF position, the one-chip microcomputer 51 of the light control unit 50 reads that it is set to the OFF position and the operating lighting relay r1 is turned off. Then, the low beam lamp Lo is turned off, and at the same time, data indicating that the low beam lamp Lo is turned off is sent to the multiple signal line 80 via the transmission interface circuit 54.

Therefore, the power supply unit 10 receiving this data detects that the operation of the light control unit 50 has stopped, and the current consumption Ia of the stopped light control unit 50 is detected from the data table.
Control unit 20, 30, 4 in operation excluding
The consumption current Ia of 0 and 60 is immediately read, and the read consumption current Ia and the supply current Ib are compared. Here, since only the light control unit 50 is in operation, Ia becomes 0, and if a value other than this is detected, it is determined that an abnormal current is flowing, and the power relay RL is turned off to supply current. Shut off.

By the way, in the above example, the case where only one light control unit 50 is operated has been described, but at the same time, two or more control units 20,
When 30, 40, 50, 60 operate, a plurality of control units 20, 30, 40, 50, 60, 9
Since the data indicating the operation is transmitted from 0, the power supply unit 10 that has received the data reads out the consumed current Ia of the control units 20, 30, 40, 50, 60 from the data table and adds the consumed currents Ia. The required current consumption Ia is calculated. Then, the calculated current consumption Ia and the current supply line 70 detected by the current detection circuit 12
Is compared with the actual supply current Ib flowing through.

For example, when the wiper unit 20, the power window unit 30, the door lock unit 40, and the light unit (Lo) 50 are simultaneously operated, the respective consumed currents 7A, 5A, 2A, 5A read from the data table. Is added and the added total value 19A is compared with the supply current Ib flowing through the shunt resistor Rs as the consumption current Ia required at this time. When Ia> Ib, it is determined to be normal, and the current supply is continued while the power relay RL is kept ON. Also,
In the case of Ia <Ib or Ia >> Ib, it is determined that an abnormal current is flowing due to a short circuit or a disconnection, and the power relay is turned off to cut off the current.

On the other hand, the control unit 2 in operation
When any one of 0, 30, 40 and 50 stops operating, the control unit 20, 30, which is operating, excluding the consumption current of the stopped control unit 20, 30, 40, 50 from the data table. 40, 50
The consumption current Ib is read out and added, and the consumption current Ib calculated by the addition is compared with the actual supply current Ia.

For example, when data indicating that the wiper unit 20 has stopped is sent to the multiple signal line 80, the power supply unit 10 removes the stopped wiper unit from the data table, and the operating power window unit 30, Door lock unit 40, light unit (Lo
Current value of 50, 5A, 2A, and 5A are read out, added, and recalculated to calculate the required current consumption Ia at this time and the actual supply current Ib flowing through the current supply line 70. And when Ia> Ib, it is determined to be normal, and the current supply is continued with the power relay RL kept ON. In the case of Ia <Ib or Ia >> Ib, an abnormal current is flowing due to a short circuit or disconnection, so the power relay RL is turned off to interrupt the current.

On the contrary, the control unit 6 being stopped
When 0 and 70 are in operation, the consumption currents of the control units 60 and 70 in operation are read out from the data table and added, and the consumption current Ia required at this time is recalculated. Current supply line 70 at this time
Is compared with the actual supply current Ib that flows through, and when Ia> Ib, it is determined to be normal, and the supply of current is continued with the power relay RL kept ON. Also, Ia <Ib or Ia >>
In the case of Ib, an abnormal current is flowing due to a short circuit, disconnection, etc., so the power relay RL is turned off to interrupt the current.

As described above, in this automobile power supply device, each control unit 20, 30, 40, 50,
The consumption current Ia required by each control unit 20, 30, 40, 50, 60 is calculated based on the operation status transmitted from 60, and the calculated value and the actual supply current Ib are calculated.
The abnormal current is constantly monitored and detected by comparing with the above, and for example, a phenomenon such as a rare short circuit in which the damaged part contacts the body many times for a very short time due to damage to the wire coating, or the conductor in the wire is broken. Even if such a phenomenon occurs, it can be detected immediately.

By the way, when detecting the supply current value Ib in this way, for example, the light control unit 50 is used.
In the case of driving a lamp or a motor load such as a power window control unit 30 or a power window control unit 30, a rush current flows at the time of operation. Therefore, if the current is detected and the actual supply current Ib is detected, an error occurs in comparison. There's a problem. Therefore, in this embodiment, after comparing the consumption current Ia and the supply current Ib with each other after detecting the operating state of the load, after a certain period of time, for example, about 50 msec, a rush current is not output in a steady state. I am going to start from.

This delay time can be easily realized when the microcomputer 11 of the power supply unit 10 sets it by a program timer or the like.

The data table provided in the power supply unit 10 may be provided with a ROM in the memory circuit of the microcomputer 11 and preset in the ROM. However, instead of the ROM, the data table is stored. As a memory of the memory, for example, a memory capable of “writing” and “erasing” such as a FLASH memory is provided.
The microcomputer 11 may overwrite the current value input to the A / D conversion input ADin by operating the switch 16 in the LASH memory.

At this time, as described above, an address is given to each control unit 20, 30, 40, 50, 60. For example, the write control unit 50 is turned on and the other control units 20, 3 are turned on.
After turning OFF all of 0, 40, and 60 so that only the current of the light control unit 50 flows through the current supply line 70, when the switch 16 is operated, the microcomputer 11 causes the current flowing through the current supply line 70 at that time. If the A / D conversion value of is used as a new table value and can be overwritten in the FLASH memory based on the above address, the data table can be easily updated.

By doing so, the table values can be easily changed even when the electrical equipment is replaced and the standard is changed from the conventional one and the current consumption is changed.

When new electric components are added, the increased control units 20, 30, 40, 5 are added.
After assigning a new address to 0 and 60, they are connected to the current supply line 70 and the multiple signal line 80, the control units 20, 30, 40, 50 and 60 are turned on, and the other control units 20 and 30 are turned on. , 40, 50, 60
When all the switches are turned off and the switch 16 is operated, if the microcomputer 11 adds the table value by the new address to the data table, it is possible to easily cope with the increase in the number of electrical components.

At this time, the A / D conversion value to be overwritten on the data table has a predetermined margin of, for example, 20%.
By memorizing the added amount, it is erroneous even if the current consumption of the control units 20, 30, 40, 50, 60 increases due to the increase of the outside temperature or the increase of the ambient temperature due to the heat generation. You can prevent it from being judged as a short.

As this method, for example, the microcomputer 11 may be provided with a program for giving a predetermined offset value to the data to be rewritten.

[0063]

As described above, the present invention is configured as described above, and is provided with a wiper unit, a power window unit, a door lock unit, a light unit ...
..The operating status of each load unit such as .. and the actual current supplied from the battery are constantly monitored, and if it is detected that the supply current is more than the current consumption required by each load unit, Since the current supply is cut off, the occurrence of a rare short circuit in which the broken portion of the wire contacts the body or the like for an extremely short time as well as during a short circuit is prevented to prevent smoking, and a wire break is also detected.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment.

FIG. 2 is a block diagram of a power supply unit according to an embodiment.

FIG. 3 is a block diagram of a light control unit according to the embodiment.

FIG. 4 is a block diagram showing a conventional example.

[Explanation of symbols]

 10 power supply unit 20 wiper control unit 30 power window control unit 40 door lock control unit 50 light control unit 60 ABS control unit 70 current supply line 80 multiple signal line B vehicle battery Ia current consumption Ib supply current

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motonori Kido 1-7-10 Kikusumi, Minami-ku, Nagoya City Harness Research Institute, Inc. (72) Hideaki Toyama 1-7-Kikuzumi, Minami-ku, Nagoya No. 10 Harness Research Institute of Stock Companies (72) Inventor Akio Matsumaru 1-7-10 Kikuzumi Minami-ku, Nagoya City Harness Research Institute of Stock Companies

Claims (4)

[Claims] 1. An operating condition of each load unit such as a wiper unit, a power window unit, a door lock unit, and a light unit, which is connected to an on-vehicle battery, and a supply current from a battery are constantly monitored. Calculate the consumption current required by the load unit, compare the calculated consumption current with the supply current from the battery, and if it detects that the supply current is excessive or insufficient than the required consumption current, the load from the battery A power supply device for automobiles that shuts off the power supply to the unit. 2. The automobile power supply device has a power supply unit connected to each load unit by a multiple signal line, and the operating condition in which the power supply unit is output from each load unit via the signal line. The vehicle power supply device according to claim 1, wherein the required current consumption is calculated based on the above. 3. The vehicle according to claim 1, wherein the calculated consumption current of the load unit and the calculated supply current are compared with each other after a certain period of time has elapsed after detecting the operating state of the load unit. Power supply device. 4. The load unit has a memory for storing a current consumption value of each load unit, and the load unit needs a value obtained by detecting a current value flowing in each load unit and adding a predetermined margin to the memory. 4. The power supply device for an automobile according to claim 1, wherein the power supply device for an automobile is stored as a consumption current and compared with the supply current based on the stored value.