JP2009299560A - Power-supply unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power-supply unit for a vehicle, which has an electric power line commonly used in a generator and a starter, in which wiring of the electric power line is easy and increase in cost is not caused, and weight of the electric power line can be reduced. <P>SOLUTION: The power-supply unit for a vehicle includes a battery 3 connected to a generator 5 by a first electric power line 7 and charged with electric power generated by the generator 5, supplies the electric power from the battery 3 to a starter 6 of an engine 2 through a second electric power line 8, and is provided with each ON/OFF signal of an ignition switch and a starting switch of the engine 2 from the external. The second electric power line 8 functions as a part 8 on a battery 3 side of the first electric power line 7. The power-supply unit further includes an electronic fuse 9 disposed on the battery 3 side of the second electric power line 8, having a first breaking property of the fuse to be applied for the first electric power line 7 and a second breaking property of the fuse to be applied for the second electric power supply line 8, and applying the first and second breaking properties thereto after switching them. The electric fuse 9 has constitution performing switching between first and second breaking properties, based on each ON/OFF signal of an ignition switch and a start switch. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device that includes a battery that is charged with electric power generated by a generator in conjunction with an engine and supplies electric power from the battery to a starter that starts the engine.

Conventionally, in a vehicle power supply device, for example, as shown in FIG. 7A, an alternator (generator, alternator) 5 and a starter 6 attached to an engine 2 disposed at the front portion of the vehicle 1 and a battery 3 is connected by a power line. Here, the alternator 5 is connected to the positive electrode of the battery 3 via the fuse 12 in the fuse box 4, for example, by a relatively thin power line 11 having a cross-sectional area of 15 mm ² . The starter 6 is connected to the positive electrode of the battery 3 via a fuse 14 outside the fuse box 4, for example, with a thick power line 13 having a cross-sectional area of 40 mm ² .

As shown in FIG. 7B, in the vehicle power supply device in which the battery 3 is arranged at the rear part of the vehicle 1, the power line 11a for the alternator 5 is routed to the fuse box 4 at the rear part of the vehicle 1, 4 is connected to the positive electrode of the battery 3 via a fuse 12 in the battery 4. The power line 13 a for the starter 6 is also routed to the rear part of the vehicle 1 and connected to the positive electrode of the battery 3 via the fuse 14 outside the fuse box 4.
As shown in FIG. 7B, when the battery 3 is disposed at the rear of the vehicle 1, the power line is thicker than in the case shown in FIG.

FIG. 8 is a timing chart showing a transition example of current and voltage of the power lines 13 and 13a on the starter 6 side and the power lines 11 and 11a on the alternator 5 side.
Even if the ignition key is inserted (key-in), the accessory switch is turned on (ACC on), and the ignition switch for turning on / off the ignition device is turned on (IG on), each power line 13, 13a, 11, 11a No current flows (FIGS. 8A and 8B). Moreover, each power line 13, 13a, 11, 11a is in the state to which the terminal voltage of the battery 3 was applied (FIGS. 8C and 8D).

  When the start switch is turned on (ST on), the starter (starting motor) 6 has an inrush current of 300 to 800 A, for example, and then the starter 6 motor current flows through the power lines 13 and 13a on the starter 6 side. (FIG. 8 (a)). Due to the voltage drop corresponding to the inrush current and the motor current, the terminal voltage of the battery 3 to each of the power lines 13, 13a, 11, and 11a drops (FIGS. 8C and 8D).

When the engine is started and the start switch is turned off (ST off), only the ignition switch is turned on (IG on), and no current flows through the power lines 13 and 13a on the starter 6 side (FIG. 8). (A)). When the engine starts and settles, the alternator 5 starts generating power, and a power generation current of, for example, a maximum of 150 A converted to direct current flows through the power lines 11 and 11a (FIG. 8B). Further, the charging voltage of the battery 3 is applied to each of the power lines 13, 13a, 11, 11a (FIGS. 8C and 8D).
From the above, the same current does not flow through the power lines 13 and 13a on the starter 6 side and the power lines 11 and 11a on the alternator 5 side, and neither current flows simultaneously.

Therefore, as the power lines 11 and 11a on the alternator 5 side, as shown in the characteristic diagram of FIG. 5A, power lines having smoke generation characteristics that do not emit smoke at 150A or less are used. The fuse 12 is a fuse having a fusing characteristic (cut-off characteristic) that is safer than the smoke generation characteristic.
As shown in the characteristic diagram of FIG. 5B, the power lines 13 and 13a on the starter 6 side use power lines having smoke generation characteristics that do not generate smoke even when a current of 300 A for 1 second and 800 A for 1 second flows. The fuse 14 is a fuse having a fusing characteristic (cut-off characteristic) that is safer than the smoke generation characteristic.

Patent Document 1 discloses a power supply network device used for a vehicle in which a battery is mounted at a position away from an engine room. The power supply network device supplies power to a plurality of power supply centers distributed and a battery to a first power supply center, and further supplies power from the first power supply center to a second power supply center. And a power bus for supplying power.
JP 2000-186666 A

As the number of electric devices mounted on vehicles increases, the power lines of the power supply system become thicker, and the weight and occupied volume cannot be ignored. In particular, as shown in FIG. 7B, when the battery 3 is disposed at the rear of the vehicle, the weight of the power lines 11a and 13a increases.
On the other hand, as shown in FIG. 6, a vehicle power supply device including a power line 10 shared as a power line for the alternator 5 and a power line for the starter 6 is conceivable. Has been. However, the shared power line 10 needs to be matched with the power line for the thicker starter 6 for fuse matching and becomes very thick. Therefore, the power line arrangement to the alternator 5 in a limited space is limited. There is a problem that it is difficult and causes an increase in work cost during manufacturing.

  The present invention has been made in view of the circumstances as described above, and includes a power line shared as a power line for a generator and a power line for a starter, and it is easy to arrange the power line to the generator. An object of the present invention is to provide a vehicular power supply device that can reduce the weight of a power line without increasing the manufacturing cost during manufacturing.

  A vehicle power supply device according to a first aspect of the present invention is a starter that includes a battery that is connected to a generator that generates power in conjunction with an engine through a first power line and that is charged by the power generated by the generator, and that starts the engine. In the vehicular power supply apparatus configured to supply power from the battery through a second power line, and to provide each on / off signal of the ignition switch and start switch of the engine from the outside, the second power line includes the It also serves as a part of the battery side of the first power line, and is provided on the battery side of the second power line. An electronic fuse having a second breaking characteristic of the power fuse and switching and applying the first breaking characteristic and the second breaking characteristic, and the electronic fuse includes the ignition fuse. The first cutoff characteristic is applied when only the ON signal of the switch is given, and the second cutoff characteristic is applied when both the ignition switch and start switch ON signals are given. It is characterized by being.

  In this vehicle power supply device, a battery connected to a generator that generates power in conjunction with the engine is charged by the power generated by the generator, and the starter that starts the engine uses the second power line to supply power from the battery. Supply. Each on / off signal of an engine ignition switch and a start switch is given from the outside. The second power line also serves as part of the battery side of the first power line. The electronic fuse provided on the battery side of the second power line has a first breaking characteristic that the fuse to be applied to the first power line has, and a second breaking characteristic that the fuse to be applied to the second power line has, The switching characteristic and the second blocking characteristic are switched and applied. The electronic fuse applies the first interruption characteristic when only the ON signal of the ignition switch is given. Further, when both ON signals of the ignition switch and the start switch are given, the second cutoff characteristic is applied.

  The vehicle power supply device according to a second aspect of the present invention is configured such that the first power line connects the generator and the starter, and the second power line connects the starter and the battery. And

  According to a third aspect of the present invention, there is provided a vehicular power supply apparatus, wherein the electronic fuse is configured to cut off the second power line when an off signal of the ignition switch is given.

  According to the vehicle power supply device of the first and second inventions, the power line for the generator and the power line shared as the power line for the starter are provided, and it is easy to arrange the power line to the generator. A power supply device for a vehicle that can reduce the weight of the power line without increasing the work cost can be realized.

  According to the vehicle power supply device of the third aspect of the present invention, the power line for the generator and the power line shared as the starter power line are provided. Thus, it is possible to achieve a vehicle power supply device that can reduce the weight of the power line without increasing the power consumption. Further, when the engine is stopped, the generator and starter power lines that do not need to be energized are not energized, so the possibility of a short circuit is reduced.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a schematic diagram schematically showing a main configuration of an embodiment of a vehicle power supply device according to the present invention.
In this vehicle power supply device, the battery 3 is disposed at the rear of the vehicle 1 as the capacity of the battery 3 increases. An alternator (generator, AC generator) 5 and a starter 6 attached to an engine 2 disposed in the front portion of the vehicle 1 are connected by a relatively thin power line 7. The positive poles of the starter 6 and the battery 3 are connected by a thick and long power line 8.

Here, the cross section of the power line 7 connecting the alternator 5 and the starter 6 is 15 mm ² , for example. The power line 8 connecting between the starter 6 and the positive pole of the battery 3 has a cross-sectional area of, for example, 60 mm ² . The power line 8 is connected to the positive electrode of the battery 3 via an electronic fuse 9 provided outside the fuse box 4 disposed at the rear of the vehicle 1. The electronic fuse 9 is provided in the vicinity of the battery 3.

FIG. 2 is a block diagram illustrating a configuration example of the electronic fuse 9.
In the electronic fuse 9, a cutoff switch 15 for connecting / cutting off the power line 8 is provided in the middle of the power line 8. A control signal for controlling connection / disconnection is supplied to the cutoff switch 15 from a microcomputer (hereinafter referred to as a microcomputer) 16.
The microcomputer 16 has an ignition switch on / off signal (IG signal) for turning on / off an ignition device (not shown) of the engine 2 and a starter 6 of the engine 2 on / off from a control system (not shown) of the engine 2. An on / off signal (ST signal) of the start switch to be turned off is given. The current detector 18 detects the value of the current flowing through the power line 8 and gives it to the microcomputer 16.

The memory 17 incorporated in the microcomputer 16 stores a fuse breaking characteristic (melting characteristic) as shown in FIG. 5C to be applied to the power line 7 having a cross-sectional area of 15 mm ² on the alternator 5 side. . The memory 17 also stores a fuse cutoff characteristic (melting characteristic) as shown in FIG. 5C to be applied to the power line 8 having a cross-sectional area of 60 mm ² on the starter 6 side.
The microcomputer 16 switches and applies the cutoff characteristics of the two fuses based on the on / off signals given by the ignition switch and the start switch of the engine 2. Moreover, the time when the current value given from the current detector 18 continues is measured, and when the relation between the current value and the time exceeds the applied cutoff characteristic, the cutoff line 15 is cut off by the cutoff switch 15.

Hereinafter, an example of the operation of the vehicular power supply apparatus having such a configuration will be described with reference to the flowchart of FIG. 3 showing the operation and the timing chart of FIG. 4 showing an example of the transition of the current and voltage of the power line.
Even when the ignition key is inserted (key-in) and the accessory switch is turned on (ACC on), the electronic fuse 9 turns off the cutoff switch 15. Therefore, no current flows through the power line 7 on the alternator 5 side and the power line 8 on the starter 6 side (FIGS. 4A and 4B), and the terminal voltage of the battery 3 is not applied (FIGS. 4C and 4B). d)).

When the ignition switch is turned on (IG on) and an ignition switch on signal is given (S1), the microcomputer 16 applies the cutoff characteristic of the fuse to be applied to the power line 7 on the alternator 5 side (S3, FIG. 4 (e)). Next, the cutoff switch 15 is turned on (S5, FIG. 4 (g)). As a result, no current flows through the power line 7 on the alternator 5 side and the power line 8 on the starter 6 side (FIGS. 4A and 4B), but the terminal voltage of the battery 3 is applied (FIG. 4). (C), (d)).
In this state, the microcomputer 16 turns off the cutoff switch 15 when the relationship between the current value supplied from the current detector 18 and its continuous time exceeds the applied cutoff characteristics.

Next, when the start switch is turned on (ST on) and the start switch on signal is given (S7), the microcomputer 16 applies the cutoff characteristic of the fuse to be applied to the power line 8 on the starter 6 side (S7). S9, FIG. 4 (e)).
At this time, after an inrush current of, for example, 300 to 800 A of the starter (starting motor) 6 flows through the power line 8 on the starter 6 side, the motor current of the starter 6 flows (FIG. 4A). Moreover, the terminal voltage of the battery 3 applied to each power line 7 and 8 falls by the voltage drop according to this inrush current and motor current (FIGS. 4C and 4D).
In this state, the microcomputer 16 turns off the cutoff switch 15 when the relationship between the current value supplied from the current detector 18 and its continuous time exceeds the applied cutoff characteristics.

Next, the microcomputer 16 is applied to the power line 7 on the alternator 5 side when the engine is started, the start switch is turned off (ST off), and the start switch off signal and the ignition switch on signal are given (S11). The cutoff characteristic of the fuse to be applied is applied (S13, FIGS. 4E and 4F).
At this time, no current flows through the power line 7 on the alternator 5 side and the power line 8 on the starter 6 side (FIGS. 4A and 4B), but the terminal voltage of the battery 3 is applied (FIG. 4 ( c), (d)).
When the engine 2 starts and settles, the alternator 5 starts generating power, and a power generation current of, for example, 150 A at maximum converted to direct current flows through the power lines 7 and 8 (FIGS. 4A and 4B). Further, the charging voltage of the battery 3 is applied to the power lines 7 and 8 (FIGS. 4C and 4D).

In this state, the microcomputer 16 turns off the cutoff switch 15 when the relationship between the current value supplied from the current detector 18 and its continuous time exceeds the applied cutoff characteristics.
Next, the microcomputer 16 turns off the cutoff switch 15 (S17) when the operation is finished, the ignition switch is turned off (S15), and the respective off signals of the start switch and the ignition switch are given. Next, the ignition switch is turned on (IG on) and waits until an ignition switch on signal is given (S1).

It is a schematic diagram which shows typically the principal part structure of embodiment of the power supply device for vehicles which concerns on this invention. It is a block diagram which shows the structural example of an electronic fuse. It is a flowchart which shows the example of operation | movement of the vehicle power supply device which concerns on this invention. It is a timing chart which shows the example of transition of the electric current of the power line of the power supply device for vehicles concerning the present invention, and a voltage. It is a characteristic view which shows the smoke generation characteristic of a power line, and the interruption | blocking characteristic (melting | fusing characteristic) of a fuse and an electronic fuse. It is a schematic diagram which shows typically the example of a principal part structure of the conventional vehicle power supply device. It is a schematic diagram which shows typically the example of a principal part structure of the conventional vehicle power supply device. It is a timing chart which shows the example of transition of the electric current of the power line of the conventional vehicle power supply device, and a voltage.

Explanation of symbols

1 vehicle 2 engine 3 battery 4 fuse box 5 alternator (generator, alternator)
6 Starter 7, 8 Power line 9 Electronic fuse 15 Shut-off switch 16 Microcomputer 17 Memory 18 Current detector

Claims (3)

A battery connected to a generator that generates power in conjunction with the engine via a first power line and charged by the power generated by the generator is supplied with power from the battery via a second power line to a starter that starts the engine. In the vehicular power supply apparatus configured so that each on / off signal of the ignition switch and the start switch of the engine is given from the outside,
The second power line also serves as a part of the battery side of the first power line, is provided on the battery side of the second power line, and has a first breaking characteristic that a fuse to be applied to the first power line has, and The fuse to be applied to the second power line has an electronic fuse having a second interruption characteristic, and is applied by switching between the first interruption characteristic and the second interruption characteristic, and the electronic fuse has an ON signal of the ignition switch The first shut-off characteristic is applied when only the ON signal is given, and the second shut-off characteristic is applied when both ON signals of the ignition switch and the start switch are given. A vehicle power supply device.   2. The vehicle power supply device according to claim 1, wherein the first power line connects the generator and the starter, and the second power line connects the starter and the battery.   3. The vehicle power supply device according to claim 1, wherein the electronic fuse is configured to cut off the second power line when an off signal of the ignition switch is given. 4.

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