JP2016060427A - Power supply system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system for a vehicle capable of reducing thickness of an electric wire constituting a wire harness and size of a device, with no significant rising of a cost being accompanied.SOLUTION: In a main power distribution box (10), a plurality of semiconductor switching devices 12, 13, 14 are provided which turn on/off power supply to each of a plurality of sub power distribution boxes (20, 30, 40). A function of an electronic fuse which shields an output current at the occurrence time of abnormality is mounted on the semiconductor switching device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle power supply system.

  On a vehicle, it is necessary to appropriately supply power to an enormous number of various electrical components from an alternator (generator) or a battery as a main power source. Also, in such a system used for power supply, there is a function for switching on / off the power supply as necessary, and a function for cutting off the current for each system when an excessive current flows through the electrical components. It is necessary to install.

  As conventional techniques related to such a vehicle power supply system, for example, each technique of Patent Documents 1 to 4 is known.

  Patent Document 1 shows a configuration in which power supplied from a vehicle alternator and a battery is supplied to various loads via a junction box 1. In addition, a large number of semiconductor relays are arranged inside the junction box 1 in order to switch on and off the power supplied to each of a large number of loads.

  In patent document 2, the electric power supply system for vehicles is shown. That is, FIG. 1 and FIG. 2 show a relay box 101, a fuse box 102, a battery 104, a plurality of connector boxes, and various electrical components, which are connected via wire harnesses provided for each system. It is connected.

  In patent document 3, the junction box for vehicles is shown. In the configuration shown in FIG. 7B, the sub power distribution box 12 is arranged downstream of the power source 27 and the power distribution box 5 is connected to the downstream thereof via the wire harness 30. A plurality of relays are arranged inside the sub power distribution box 12, and a plurality of fuses are arranged inside the power distribution box 5.

  Patent Document 4 shows a vehicle power supply system. In the configuration shown in FIG. 1, a first power supply box 110 is connected to the outputs of the battery 101 and the alternator 102, and a plurality of second power supply boxes 140 are connected downstream thereof. In addition, relays and a large number of fuses are arranged inside the first power supply box 110 and the second power supply box 140, respectively.

JP 2002-51430 A JP 2005-289375 A JP 2009-165328 A JP 2009-220601 A

  In a vehicle, it is necessary to provide a function of switching power supply on and off as necessary for each of a plurality of systems. A specific example will be described. In the case of a general vehicle, an ignition switch that switches on and off in conjunction with an operation of an engine key or a smart key, and an accessory switch are provided. Further, there are a power supply system (first system) in which power is supplied only when the ignition (IG) switch is on and a power supply system (second system) in which power is supplied only when the accessory (ACC) switch is on. It is provided in an independent state.

  Therefore, when the load of the first system requires a large amount of power, for example, when the cell motor is rotated to start the engine, the power supply of the second system is temporarily interrupted, and the first system It is also possible to preferentially supply power only to the grid. This facilitates starting the engine of the vehicle. Even when the ignition switch is turned off and the engine is stopped, by turning on the accessory switch, various electrical components (for example, car audio devices) connected to the output side of the second system Can be used.

  On the other hand, since many loads (electrical components) are arranged at various locations on the vehicle, the length and thickness of the wire harness connecting the power source and each load, the number of wires, etc. are optimized. There is a need to. Therefore, for example, as in Patent Document 4, a configuration in which the first power supply box 110 is connected to the outputs of the battery 101 and the alternator 102 and a plurality of second power supply boxes 140 are connected downstream thereof may be employed. is there.

  However, for example, in the wire harness connecting between the first power supply box 110 and the second power supply box 140 in Patent Document 4, it is difficult to reduce the diameter of the electric wire. Have difficulty.

  That is, since the first power system 140 and the second system described above are included in the second power supply box 140, the maximum value of the current supplied to the first system and the maximum value of the current supplied to the second system The total current is passed through the wires constituting the wire harness. In order to prevent an abnormal temperature rise or burnout due to heat generation of the electric wire itself when a large current flows, it is necessary to increase the diameter of the electric wire used (conductor cross-sectional area) to reduce the electrical resistance of the conductor.

  Further, since it is necessary to switch on / off of power supply for each of the plurality of power supply systems, a relay used for this switching must be provided for each power supply system. In addition, since a plurality of relays are arranged inside the second power supply box 140, if the number of the second power supply boxes 140 increases, the total number of relays included in the system becomes very large. As a result, an increase in weight and an increase in cost are expected.

  Further, the mechanical relay has a problem that the response speed is relatively slow. Further, a mechanical fuse or a general fusible link (FL) cannot precisely control the current interruption characteristics, and it is inevitable that the interruption characteristics vary. Therefore, it is necessary to consider these response delays and variations in characteristics. Therefore, for the wires that make up the wire harness, it is necessary to use wires with a larger diameter so that there is room for the allowable current. The fact is that you cannot get it.

  Therefore, for example, as shown in Patent Document 1, it is conceivable to employ a semiconductor relay instead of a mechanical relay. However, since semiconductor relays are considerably more expensive than general mechanical relays, mounting a large number of semiconductor relays in an actual vehicle as in Patent Document 1 is not practical in terms of cost.

  Further, as the number of components arranged inside the first power supply box 110 and the like increases, the apparatus becomes larger. Therefore, an extra space for arranging the first power supply box 110 must be secured on the vehicle. However, it is desired to reduce the size.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is for a vehicle capable of reducing the diameter of an electric wire constituting a wire harness and reducing the size of the device without significantly increasing the cost. It is to provide a power supply system.

In order to achieve the above-described object, a vehicle power supply system according to the present invention is characterized by the following (1) to (6).
(1) Main power distribution box,
A plurality of independent sub power distribution boxes connectable downstream of the main power distribution box;
A wire harness electrically connecting each of the main power distribution box and the plurality of sub power distribution boxes;
With
A vehicle power supply system for supplying power to a plurality of loads connected downstream of each sub power distribution box,
The main power distribution box is provided with a plurality of relays for turning on and off the power supply to each of the plurality of sub power distribution boxes,
Each of the plurality of relays is configured using a semiconductor switching element, and the semiconductor switching element is equipped with a function of an electronic fuse that cuts off an output current when an abnormality occurs.
A power supply system for a vehicle.
(2) The vehicle power supply system according to (1) above,
The plurality of relays have a first relay that turns on / off power supply to a first electric system whose power supply is controlled based on first information, and power supply is controlled based on second information. A second relay for turning on and off the power supply to the second electric system,
In the main power distribution box, the first relay and the second relay are arranged,
A power supply system for a vehicle.
(3) The vehicle power supply system according to (2) above,
The first electric system is arranged in a first sub power distribution box among the plurality of sub power distribution boxes,
The second electric system is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle.
(4) The vehicle power supply system according to (2) above,
In any one of the plurality of sub power distribution boxes, the first electric system and the second electric system are arranged,
A power supply system for a vehicle.
(5) The vehicle power supply system according to (2) above,
The main power distribution box is provided with a third relay for turning on / off the power supply to the third electric system whose power supply is controlled based on the third information,
In the first sub power distribution box of the plurality of sub power distribution boxes, the first electric system and the second electric system are arranged,
The third relay is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle.
(6) The vehicle power supply system according to (1) above,
The electronic fuse has fusible link interrupting characteristics;
A power supply system for a vehicle.

According to the vehicle power supply system having the configuration (1) above, the relay that has been conventionally arranged in the sub power distribution box on the downstream side is moved to the main power distribution box on the upstream side to distribute the main power distribution on the upstream side. As a result of eliminating the relay from the downstream sub power distribution box while consolidating the relays in the box, it is not necessary to provide a relay in each of the downstream sub power distribution boxes, so the number of relays provided in the entire system can be reduced. Further, it is possible to reduce the diameter of the electric wires constituting the wire harness and reduce the size of the apparatus without significantly increasing the cost. That is, by configuring the plurality of relays with semiconductor switching elements, it becomes possible to integrate the function of the electronic fuse into these relays, and the total number of parts and the volume of the device can be reduced. In addition, since the electric fuse can control the current interruption characteristics with high accuracy, it is not necessary to provide more room for the wire thickness of the wire harness connected to the downstream side, and the wire diameter can be reduced. .
According to the vehicle power supply system having the configuration (2) described above, the power supply box can be simplified without significant cost increase, and thus the entire system can be simplified. That is, by arranging relays inside the main power distribution box and eliminating the relays from the sub power distribution box to reduce the total number of relays, the power distribution box can be simplified. Miniaturization is also possible. As a result of simplifying the power distribution box, the configuration of the entire vehicle power supply system is simplified.
According to the vehicle power supply system having the configuration (3) described above, the power supply box can be simplified without significant cost increase, and thus the entire system can be simplified. That is, it is not necessary to incorporate a plurality of electrical systems in the first sub power distribution box, and it is not necessary to incorporate a plurality of electrical systems in the second sub power distribution box. Therefore, these relays are collectively arranged inside the main power distribution box, and the total number of relays is reduced by eliminating relays from the first sub power distribution box and the second sub power distribution box. Thus, the power distribution box can be simplified and the size can be reduced. As a result of simplifying the power distribution box, the configuration of the entire vehicle power supply system is simplified.
According to the vehicle power supply system having the configurations of (4) and (5) above, the relays are collectively arranged inside the main power distribution box, and the relays are excluded from the inside of the sub power distribution box. By reducing the total number, the power distribution box can be simplified and the size can be reduced.
According to the vehicular power supply system having the configuration (6), it is possible to obtain a cutoff characteristic peculiar to the fusible link. For example, if an excessively large current flows instantaneously, the current will not be interrupted, and if a large current that causes an abnormal temperature rise in the wire harness flows for a certain amount of time, the current is reliably supplied. The wire harness etc. which interrupted | blocked and was connected downstream can be protected so that it may not burn out.

  According to the vehicle power supply system of the present invention, relays are not provided in each of the sub power distribution boxes on the downstream side, so the number of relays provided in the entire system can be reduced. Further, it is possible to reduce the diameter of the electric wires constituting the wire harness and reduce the size of the apparatus without significantly increasing the cost. That is, by configuring the plurality of relays with semiconductor switching elements, it becomes possible to integrate the function of the electronic fuse into these relays, and the total number of parts and the volume of the device can be reduced. In addition, since the electric fuse can control the current interruption characteristics with high accuracy, it is not necessary to provide more room for the wire thickness of the wire harness connected to the downstream side, and the wire diameter can be reduced. .

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is a block diagram showing a configuration of a vehicle power supply system according to an embodiment of the present invention. FIG. 2 is a flowchart showing a main flow regarding the operation of the main power distribution box. FIG. 3 is a flowchart showing details of S13 in FIG. FIG. 4 is a flowchart showing details of S14 of FIG. FIG. 5 is a block diagram showing a configuration of a vehicular power supply system having a general configuration not including the features of the present invention. 6A is a perspective view illustrating a specific example of the appearance of the main power distribution box according to the embodiment of the present invention, and FIG. 6B is a perspective view illustrating a specific example of the appearance of a multi-FL block having a general configuration. It is. FIG. 7 is a block diagram showing a configuration of another modified example of the vehicle power supply system according to the embodiment of the present invention.

  Specific embodiments of the vehicle power supply system of the present invention will be described below with reference to the drawings.

<System configuration example>
<Overview of overall system>
The configuration of the vehicle power supply system according to the embodiment of the present invention is shown in FIG. The vehicle power supply system shown in FIG. 1 has a main power distribution box 10 and three sub power distributions as main components for supplying power to various loads (electrical components) on the vehicle. Boxes 20, 30, and 40 are provided.

  The main power distribution box 10 is disposed, for example, in the engine room of the vehicle, the sub power distribution box 20 is disposed near the left end of the vehicle dashboard, and the sub power distribution box 30 is disposed near the right end of the vehicle dashboard. The sub power distribution box 40 is disposed in a luggage space (luggage room) of the vehicle. That is, the main power distribution box 10 and the sub power distribution boxes 20, 30, and 40 are disposed at locations that are separated from each other, and these are electrically connected via the wire harness.

  Output terminals of an alternator 51 and an on-vehicle battery 52 which are main power sources of the vehicle are connected to the input side power source line 18 of the main power distribution box 10 via a power source line 53. In addition, about wiring, such as the power supply line 53, a bus bar may be utilized instead of an electric wire so that a big electric current can be sent.

  The plurality of output-side power supply lines 15, 16, and 17 of the main power distribution box 10 are connected to the sub power distribution boxes 20, 40, and 30 via the electric wires 61, 62, and 63 of the main wire harness 60, respectively. ing.

  Also, various accessories (ACC) loads are connected to the output terminal group 23 of the sub power distribution box 20 via the wire harness 71. Various ignition (IG1) loads are connected to the output terminal group 33 of the sub power distribution box 30 via the wire harness 72. Various loads of the ignition (IG2) system different from the ignition (IG1) system are connected to the output terminal group 43 of the sub power distribution box 40 via the wire harness 73.

  In the vehicle power supply system shown in FIG. 1, there are three types of electric systems for supplying power to various loads: an ignition (IG1) system, an accessory (ACC) system, and an ignition (IG2) system. ing.

  The ignition (IG1) system is a system in which power supply is controlled in conjunction with the on / off of the ignition switch of the vehicle, and is controlled in accordance with an ignition system signal SG_IG1 indicating on / off of the ignition switch. The accessory (ACC) system is a system in which power supply is controlled in conjunction with on / off of an accessory switch of the vehicle, and is controlled according to an accessory system signal SG_ACC indicating on / off of the accessory switch. The ignition (IG2) system is a system in which power supply is controlled in conjunction with the on / off of the ignition switch of the vehicle, and is controlled in accordance with an ignition system signal SG_IG2 indicating on / off of the ignition switch.

  For example, when a driver tries to start an engine by operating an engine key or a smart key, an ignition switch is turned on and power is supplied only to an ignition system load such as a cell motor. Smooth engine start can be realized. For example, load on accessories such as in-vehicle audio devices is supplied when the accessory switch is on, regardless of the engine operating state or the alternator operating state, unless the engine is in a special state, such as when the engine is started. It can be carried out. In addition, a load that consumes a relatively large amount of power is connected to an alternator system, and for example, the load on the vehicle battery 52 is controlled by controlling power supply to the load only when the alternator 51 is generating power. Can be reduced.

  In the configuration shown in FIG. 1, an ignition system signal SG_IG1, an accessory system signal SG_ACC, and an ignition (IG2) system SG_IG2 are input to the main power distribution box 10 from the output of an electronic control unit (ECU) 55 provided in the vehicle. The Therefore, the main power distribution box 10 can individually control the three types of electric systems according to the ignition system signal SG_IG1, the accessory system signal SG_ACC, and the ignition (IG2) system signal SG_IG2.

<Configuration of main power distribution box 10>
As shown in FIG. 1, the main power distribution box 10 includes a microcomputer (CPU) 11 and a plurality of semiconductor switching devices 12, 13, and 14. In this embodiment, IPD (Intelligent Power Device) is adopted as the semiconductor switching devices 12, 13 and 14. Although not shown, these IPDs incorporate a gate driver, an output current monitoring function, various protection functions and the like in addition to a switching element such as a power MOSFET.

  The microcomputer 11 performs processing for realizing various functions required for the main power distribution box 10 by executing a program incorporated in advance. Specifically, the microcomputer 11 controls on / off of the semiconductor switching devices 12, 13, and 14 in accordance with the states of signals SG_IG1, SG_ACC, and SG_IG2 output from the electronic control unit (ECU) 55, respectively. Thereby, the semiconductor switching devices 12, 13, and 14 are caused to function as semiconductor relays.

  Further, the microcomputer 11 constantly monitors the magnitude of the load current flowing through the outputs of the semiconductor switching devices 12, 13, and 14, and detects the output current of each circuit when a state requiring special protection is detected. Cut off. Thereby, the semiconductor switching devices 12, 13, and 14 are caused to function as semiconductor fuses. Further, since the main power distribution box 10 is disposed directly below the alternator 51 and the on-vehicle battery 52 as the main power source, the semiconductor switching device 12 is provided so as to obtain a current interruption characteristic equivalent to the fusible link (FL). , 13 and 14 are controlled.

  For example, even if an excessive current flows due to a failure or short circuit in the load, the fuse that is normally located near the load where the failure has occurred immediately shuts off the circuit. There is no flow over time, and there is no need to interrupt the circuit in the main power distribution box 10. However, if a large current flows for a long time for some reason, the temperature rises remarkably due to heat generated by the trunk wire harness 60 and the like, and there is a possibility that problems such as burning and fire may occur. Therefore, in the main power distribution box 10, the current is cut off only when a condition that causes a significant temperature increase is satisfied, that is, when an overcurrent flows for a long time. This is the fusible link function.

  That is, the functions of the semiconductor relay and the fusible link are integrated into the main power distribution box 10 for each of the ignition (IG1) system, the accessory system, and the ignition (IG2) system. It is. Further, since the semiconductor switching devices 12, 13, and 14 perform the same function as the fusible link, it is not necessary to arrange the conventional fusible link in the main power distribution box 10.

<Configuration of Sub Power Distribution Boxes 20, 30, 40>
As shown in FIG. 1, the sub power distribution box 20 includes a branch circuit 21, a fuse group 22, and an output terminal group 23. That is, the power source power supplied from the electric wire 61 to the sub power distribution box 20 is distributed for each load by the branch circuit 21 and is supplied to one of the fuse groups (22) and the output terminal group (23) provided for each load. It passes through one and is supplied to each load of the accessory (ACC) system via the wire harness 71.

  Similarly, the sub power distribution box 30 includes a branch circuit 31, a fuse group 32, and an output terminal group 33. That is, the power source power supplied from the electric wire 63 to the sub power distribution box 30 is distributed for each load by the branch circuit 31, and one of the fuse group (32) provided for each load and the output terminal group (33). One is passed through the wire harness 72 and supplied to each ignition (IG1) system load.

  Similarly, the sub power distribution box 40 includes a branch circuit 41, a fuse group 42, and an output terminal group 43. That is, the power supply power supplied from the electric wire 62 to the sub power distribution box 40 is distributed for each load by the branch circuit 41, and one of the fuse groups (42) provided for each load and the output terminal group (43). One is passed through the wire harness 73 and supplied to each ignition (IG2) load.

<Characteristic operation of the system>
<Description of main flow>
A main flow relating to the operation of the main power distribution box 10 is shown in FIG. That is, the microcomputer 11 in the main power distribution box 10 executes the process shown in FIG. 2 as a main flow.

  When the power supplied to the microcomputer 11 is turned on, the microcomputer 11 executes initialization in step S11. For example, all the semiconductor switching devices 12, 13, and 14 are controlled to be off. Also, various control flags and parameters are initialized.

  In step S12, the microcomputer 11 grasps the latest states of the accessory system signal SG_ACC, the ignition (IG2) system signal SG_IG2, and the ignition system signal SG_IG1 input from the electronic control unit (ECU) 55.

  In step S13, the microcomputer 11 performs control for causing each of the semiconductor switching devices 12, 13, and 14 to function as a semiconductor relay. That is, on / off of the semiconductor switching devices 12, 13, and 14 is controlled according to the states of the signals SG_ACC, SG_IG2, and SG_IG1 input in S12. Details of the processing will be described later.

  In step S14, the microcomputer 11 performs control for causing each of the semiconductor switching devices 12, 13, and 14 to function as a fusible link (FL). That is, the magnitude of the current flowing through each of the semiconductor switching devices 12, 13, and 14 is monitored, and the current is cut off when the condition that the FL should be cut off is satisfied. Details of the processing will be described later.

<Description of IPD On / Off Control>
FIG. 3 shows details of step S13 in FIG. 2, that is, “IPD on / off control”. The processing of FIG. 3 will be described below.

  In step S21, the microcomputer 11 identifies whether or not a change in on / off (H / L) of the ignition system signal SG_IG1 input from the electronic control unit (ECU) 55 has been detected. If a change is detected, the process proceeds to S22, and if there is no change, the process proceeds to S23.

  In step S22, the microcomputer 11 switches on / off the semiconductor switching device 14, which is an ignition (IG1) -based IPD, according to the on / off of the latest ignition-related signal SG_IG1. That is, when SG_IG1 is turned on, the semiconductor switching device 14 is switched from off to on, and when SG_IG1 is turned off, the semiconductor switching device 14 is switched from on to off. However, when a flag indicating that a fusible link (to be described later) cuts off an ignition (IG1) current is set, the semiconductor switching device 14 remains off.

  In step S23, the microcomputer 11 identifies whether or not an on / off (H / L) change of the accessory system signal SG_ACC input from the electronic control unit (ECU) 55 is detected. If a change is detected, the process proceeds to S24, and if there is no change, the process proceeds to S25.

  In step S24, the microcomputer 11 switches on / off the semiconductor switching device 12, which is an ACC IPD, in accordance with the latest accessory system signal SG_ACC. That is, when SG_ACC is turned on, the semiconductor switching device 12 is switched from off to on, and when SG_ACC is turned off, the semiconductor switching device 12 is switched from on to off. However, when a flag indicating that a fusible link (to be described later) cuts off an ACC current is set, the semiconductor switching device 12 is kept off.

  In step S25, the microcomputer 11 identifies whether an on / off (H / L) change in the ignition (IG2) system signal SG_IG2 input from the electronic control unit (ECU) 55 has been detected. If a change is detected, the process proceeds to S26, and if there is no change, this process ends.

  In step S26, the microcomputer 11 switches on / off the semiconductor switching device 13, which is an ignition (IG2) IPD, according to the on / off of the latest ignition (IG2) signal SG_IG2. That is, when SG_IG2 is turned on, the semiconductor switching device 13 is switched from off to on, and when SG_IG2 is turned off, the semiconductor switching device 13 is switched from on to off. However, when a flag indicating that a fusible link (to be described later) interrupts an ignition (IG2) current is set, the semiconductor switching device 13 remains off.

<Explanation of IPD FL control>
FIG. 4 shows details of step S14 in FIG. 2, that is, “IPD FL control”. The process shown in FIG. 4 includes an “IG1 FL process” Pig1, an “ACC FL process” Pacc, and an “IG2 FL process” Pig2. That is, Pig1 realizes the fusible link function for the ignition system, Pacc realizes the fusible link function for the accessory system, and fusible for the ignition (IG2) system. Pig2 realizes the link function.

The “IG1-based FL processing” Pig1 will be described below.
In step S31, the microcomputer 11 acquires an instantaneous value of the output current (load current) Cur_IG1 of the semiconductor switching device 14, which is an ignition (IG1) IPD, and stores it in the internal memory.

  In step S32, the microcomputer 11 calculates the average value of the current using the instantaneous value group of the output current Cur_IG1 sampled at each time point held in the internal memory.

  In step S33, the microcomputer 11 compares the current average value calculated in step S32 with a predetermined current threshold value Cig1_max to identify whether or not the current should be interrupted. If “average value of detected currents ≦ Cig1_max”, the process proceeds to the next Pacc. If “average value of detected currents> Cig1_max”, the process proceeds to the next S34.

  The current threshold Cig1_max to be used is registered as a constant on the ROM inside the microcomputer 11 or on an external nonvolatile memory (not shown). The current threshold Cig1_max is determined in advance based on characteristics such as the cross-sectional area of the conductor of the electric wire 63 and the maximum value of the total sum of current consumption of various loads connected to the ignition (IG1) system.

  In step S34, the microcomputer 11 switches off the semiconductor switching device 14, which is an ignition (IG1) IPD, and interrupts the ignition (IG1) current. In the next step S35, the microcomputer 11 sets a flag indicating that the ignition (IG1) type FL is in a state where the current is cut off.

  On the other hand, in the “ACC system FL process” Pacc of FIG. 4, the microcomputer 11 executes the same process as the above “IG1 system FL process” Pig1 with the ACC system as a processing target. The threshold value of the current used in the “ACC-based FL processing” Pacc is determined in advance based on characteristics such as the cross-sectional area of the conductor of the electric wire 61 and the maximum sum of the current consumption of various loads connected to the ACC-based system. Is done.

  Also in the “IG2 system FL processing” Pig2, the microcomputer 11 performs the same processing as the above “IG1 system FL processing” Pig1 with the ignition (IG2) system as a processing target. The threshold value of the current used in the “IG2 FL processing” Pig2 is based on the characteristics such as the cross-sectional area of the conductor of the electric wire 62 and the maximum sum of the current consumption of various loads connected to the ignition (IG2) system. Determined in advance.

<Comparison between characteristic configuration and general configuration of the present invention>
<Description of general configuration>
FIG. 5 shows the configuration of a vehicle power supply system having a general configuration that does not include the features of the present invention.
In the vehicular power supply system shown in FIG. 5, a multi-FL block 81 is connected downstream of the alternator 51. Inside the multi-FL block 81, three fusible links 81a, 81b, and 81c are included.

  The output ends of the three fusible links 81a, 81b, and 81c are connected to junction boxes (J / B) 85, 86, and 87 arranged downstream via the wires 82, 83, and 84 of the wire harness, respectively. ing.

  Each of the junction boxes 85, 86, and 87 includes an ignition (IG) system and an accessory (ACC) system electrical system. Inside the junction box 85, for each independent electrical system, a plurality of relays (IG_RLY, ACC_RLY) for switching on / off of power supply to the load side, and a large number of fuses assigned for each load are provided. Yes. The same applies to the other junction boxes 86 and 87.

<Explanation of correspondence and difference between the two configurations>
When the vehicle power supply system of the present invention shown in FIG. 1 is compared with the configuration shown in FIG. 5, the main power distribution box 10 in FIG. 1 is associated with the multi-FL block 81 in FIG. Further, the sub power distribution boxes 20, 30, and 40 in FIG. 1 can be associated with the junction boxes 85, 86, and 87 in FIG. However, there is a difference between them as described below.

(Difference 1) In the configuration of FIG. 1, the functions of the semiconductor relay and the fusible link are included in the main power distribution box 10, but in the configuration of FIG. 5, the multi-FL block 81 includes only the fusible link. ing.

(Difference 2) In the configuration of FIG. 1, only a single electric system (IG1, ACC, or IG2) is included in each of the sub-power distribution boxes 20, 30, and 40. In the configuration, each junction box 85, 86, and 87 includes a plurality of electrical systems.

(Difference 3) In the configuration of FIG. 5, each junction box 85, 86, and 87 includes a plurality of relays and a large number of fuses for turning on / off each system. Relays are not included in the power distribution boxes 20, 30, and 40.

(Difference 4) In the configuration of FIG. 1, the total number of relays in the main power distribution box 10 is 3, but in the configuration of FIG. 5, the total number of relays in the junction boxes 85, 86, and 87 is more than doubled. ing.

(Difference 5) Although the mechanical relay and the mechanical fusible link are used in the configuration of FIG. 5, the functions of the relay and the fusible link are integrated using a semiconductor switching element in the configuration of FIG.

<Advantages of the configuration of the present invention>
(Advantage 1) As explained in the above (Difference 2), each of the sub power distribution boxes 20, 30, and 40 includes only a single electric system (IG1, ACC, or IG2). Therefore, the maximum value of the current flowing through each of the electric wires 61, 62, 63 of the trunk wire harness 60 is reduced. Thereby, diameter reduction of the electric wires 61, 62, and 63 is attained. Further, as described in the above (Difference 4), the relay that has been conventionally arranged in the sub power distribution box on the downstream side is moved to the main power distribution box on the upstream side, and the relay is moved to the main power distribution box on the upstream side. As a result of eliminating the relay from the downstream sub power distribution box while consolidating, there is no need to provide a relay in each downstream sub power distribution box, so the total number of relays that control on / off of current supply for each electrical system is greatly increased. Can be reduced.

(Advantage 2) Since the semiconductor relay is more expensive than the mechanical relay, it is difficult to adopt the semiconductor relay from the viewpoint of cost when the total number of relays increases. However, when the total number of relays is small as described above (Advantage 1), an increase in cost can be suppressed even if a semiconductor relay is employed. Further, since the total number of relays for controlling on / off of the power supply is reduced, these relays are arranged together in the main power distribution box 10, and the relays are excluded from the sub power distribution boxes 20, 30, 40. The sub power distribution box can be simplified, and the sub power distribution box can be downsized. As a result of simplifying the configuration of the sub power distribution box, the configuration of the entire vehicle power supply system is simplified.

(Advantage 3) Since the fusible link is configured by using the semiconductor switching element, the variation in the current interruption characteristic is smaller than that of the mechanical fusible link, and high-accuracy interruption control is possible. Thereby, it is not necessary to give a large margin to the thickness of the wires 61 to 63 of the main wire harness 60, and the diameter of the wires can be reduced.

(Advantage 4) As described above (difference 5), since the functions of the relay and the fusible link are integrated using a semiconductor switching element, the volume of the entire apparatus can be reduced. The reduction in the total number of relays also leads to a significant reduction in the volume of the entire device.

<Description of specific examples of appearance>
A specific example of the appearance of the main power distribution box 10 shown in FIG. 1 is shown in FIG. A specific example of the appearance of the multi-FL block 81 shown in FIG. 5 is shown in FIG.

  The main power distribution box 10 shown in FIG. 6 (A) is equipped with both a relay for switching on / off of current supply for each electric system and a function of a fusible link. It has the same size as the multi-FL block 81 shown in FIG. Although not shown, the external appearances of the sub power distribution boxes 20, 30, and 40 are reduced in size as compared with the configuration of FIG.

<Description of modification>
In the embodiment of the present invention, a configuration in which one electric system (ignition (IG1) system, accessory (ACC) system, and ignition (IG2) system) is disposed in each of the sub power distribution boxes 20, 30, and 40 is provided. explained. The present invention is not limited to this configuration. As shown in FIG. 7, a plurality of electrical systems (ignition (IG1) system and ignition (IG2) system) may be arranged in one sub power distribution box 30. Even with this configuration, the maximum value of the current flowing through each of the electric wires 61, 62, 63 of the trunk wire harness 60 is reduced. Thereby, diameter reduction of the electric wires 61, 62, and 63 is attained. Furthermore, as shown in FIG. 7, a plurality of electrical systems (ignition (IG1) system and ignition (IG2) system) are arranged in a certain sub power distribution box 30, and one sub power distribution box 20 has one electrical system. A system (accessory (ACC) system) may be arranged, and the number of electric systems arranged for each sub power distribution box may be different.

Here, the features of the above-described vehicle power supply system according to the present invention are summarized and listed in the following (1) to (6), respectively.
(1) Main power distribution box (10),
A plurality of independent sub power distribution boxes (20, 30, 40) connectable downstream of the main power distribution box;
A wire harness for electrically connecting the main power distribution box and the plurality of sub power distribution boxes, respectively (main wire harness 60);
With
A vehicle power supply system for supplying power to a plurality of loads connected downstream of each sub power distribution box,
The main power distribution box is provided with a plurality of relays (semiconductor switching devices 12, 13, 14, microcomputer 11) for turning on and off the power supply to each of the plurality of sub power distribution boxes,
Each of the plurality of relays is configured using a semiconductor switching element (semiconductor switching devices 12, 13, and 14), and the semiconductor switching element is equipped with an electronic fuse function that cuts off an output current when an abnormality occurs.
A power supply system for a vehicle.
(2) The vehicle power supply system according to (1) above,
The plurality of relays is a first relay (semiconductor switching device 14) that turns on / off the power supply to the first electric system (31, 32, 33) whose power supply is controlled based on the first information (SG_IG1). , The microcomputer 11) and a second relay (semiconductor switching device) for turning on / off the power supply to the second electric system (21, 22, 23) whose power supply is controlled based on the second information (SG_ACC) 12, a microcomputer 11),
In the main power distribution box, the first relay and the second relay are arranged,
A power supply system for a vehicle.
(3) The vehicle power supply system according to (2) above,
The first electric system is arranged in a first sub power distribution box among the plurality of sub power distribution boxes,
The second electric system is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle.
(4) The vehicle power supply system according to (2) above,
In any one of the plurality of sub power distribution boxes, the first electrical system (31, 32, 33) and the second electrical system (41, 42, 43) are disposed.
A power supply system for a vehicle.
(5) The vehicle power supply system according to (4) above,
The main power distribution box has a third relay (semiconductor switching) for turning on / off the power supply to the third electric system (21, 22, 23) whose power supply is controlled based on the third information (SG_ACC). Device 12 and microcomputer 11) are arranged,
In the first sub power distribution box of the plurality of sub power distribution boxes, the first electric system and the second electric system are arranged,
The third relay is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle.
(6) The vehicle power supply system according to (1) above,
The electronic fuse has fusible link interrupting characteristics;
A power supply system for a vehicle.

DESCRIPTION OF SYMBOLS 10 Main power distribution box 11 Microcomputer 12, 13, 14 Semiconductor switching device 15, 16, 17 Output side power supply line 18 Input side power supply line 20, 30, 40 Sub power distribution box 21, 31, 41 Branch circuit 22, 32, 42 Fuse group 23, 33, 43 Output terminal group 51 Alternator 52 On-board battery 53 Power line 55 Electronic control unit (ECU)
60 Trunk wire harness 61, 62, 63 Wire 71, 72, 73 Wire harness SG_IG1 Ignition (IG1) system signal SG_ACC Accessory system signal SG_IG2 Ignition (IG2) system signal

Claims (6)

A main power distribution box,
A plurality of independent sub power distribution boxes connectable downstream of the main power distribution box;
A wire harness electrically connecting each of the main power distribution box and the plurality of sub power distribution boxes;
With
A vehicle power supply system for supplying power to a plurality of loads connected downstream of each sub power distribution box,
The main power distribution box is provided with a plurality of relays for turning on and off the power supply to each of the plurality of sub power distribution boxes,
Each of the plurality of relays is configured using a semiconductor switching element, and the semiconductor switching element is equipped with a function of an electronic fuse that cuts off an output current when an abnormality occurs.
A power supply system for a vehicle. The vehicle power supply system according to claim 1,
The plurality of relays have a first relay that turns on / off power supply to a first electric system whose power supply is controlled based on first information, and power supply is controlled based on second information. A second relay for turning on and off the power supply to the second electric system,
In the main power distribution box, the first relay and the second relay are arranged,
A power supply system for a vehicle. The vehicle power supply system according to claim 2,
The first electric system is arranged in a first sub power distribution box among the plurality of sub power distribution boxes,
The second electric system is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle. The vehicle power supply system according to claim 2,
In any one of the plurality of sub power distribution boxes, the first electric system and the second electric system are arranged,
A power supply system for a vehicle. The vehicle power supply system according to claim 4,
The main power distribution box is provided with a third relay for turning on / off the power supply to the third electric system whose power supply is controlled based on the third information,
In the first sub power distribution box of the plurality of sub power distribution boxes, the first electric system and the second electric system are arranged,
The third relay is disposed in a second sub power distribution box among the plurality of sub power distribution boxes.
A power supply system for a vehicle. The vehicle power supply system according to any one of claims 1 to 5,
The electronic fuse has fusible link interrupting characteristics;
A power supply system for a vehicle.

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