JPH05338515A - Electric power supply device for vehicle - Google Patents

Abstract

PURPOSE:To reduce the diameter of a cable for feeding electric power to a special load and also inactivate electrolytic corrosion at the connection of the cable. CONSTITUTION:An electric power supply device for vehicle is provided with connecting means SW3 to SW5 which determine the connecting conditions of multiple batteries 61 to 64 constituting a power supply device 6 for special load according to the load conditions of a special load 4 and whether the power supply device 6 for special load is under charging condition or not and a control means 7 which detects the load conditions of the special load 4 and whether the power supply device 6 for special load is under charging condition or not to control the connecting means SW3 to SW5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for supplying electric power to an electric load of a vehicle, and more particularly to a power supply device for supplying electric power to a special electric component (special load) such as a heated catalyst or a quick heater.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a conventional example of a power supply device for a vehicle. In FIG. 2, when the switch SW0 is turned on, the voltage from the battery 1, for example, 12V is supplied to the electric load 2. When the output voltage of the battery 1 drops and enters the charging state, the charging current is supplied to the battery 1 from the alternator (alternating current generator) 3.

In FIG. 2, an electric load 2 supplied with electric power from a battery 1 or an alternator 3 is a power window or a rear heating wire. Hereinafter, such an electric load is referred to as a normal load, and the battery 1 that supplies electric power to the normal load 2
Is referred to as a normal battery or a normal load power supply unit.

By the way, in recent years, in order to improve environmental conditions inside and outside a vehicle, a special electric load such as a quick heater and a heated catalyst (hereinafter referred to as "special load").
It has become necessary to prepare for. The quick heater is a heater for immediately blowing hot air to warm the room when the heating device is operated immediately after cold start. The heated catalyst is a catalyst (catalyst carrier) that is warmed by a heater in order to normally perform the catalytic action of the exhaust emission control device immediately after cold start.

The special load is a heated window shield. This is to warm the windshield with a heater to prevent the glass from fogging.

[0006]

However, the above-mentioned special load is equipped with a heater and the like, and the battery load is heavy. Therefore, it is necessary to use a large number of normal batteries 1, but if it is driven at a low voltage of 12 V as in the conventional case, the load current becomes a large current, a wire with a large wire diameter is required, and it is difficult to install in space. Is. Further, the large current activates the electrolytic corrosion action in the electric wire connection portion, and accelerates the progress of corrosion of the connection portion.

The present invention has been made to solve the above problems, and an object of the present invention is to make it possible to reduce the diameter of an electric wire for supplying electric power to a special load and to prevent electrolytic corrosion at an electric wire connecting portion. An object of the present invention is to provide a power supply device for a vehicle whose operation is inactive.

[0008]

To achieve the above object, the present invention provides a special load comprising a power supply unit for a normal load for supplying electric power to a normal load and a plurality of batteries having the same load current value. In a power supply device for a vehicle having a special load power supply unit for supplying electric power, a connection state of the plurality of batteries is determined according to a load state of the special load and whether or not the special load power supply unit is in a charging state. The connection means and the control means for controlling the connection means by detecting the load state of the special load and whether or not the special load power supply unit is in the charged state are provided.

Further preferably, in the above invention, the connecting means is controlled by the control means so as to connect all of the plurality of batteries in series when the special load power source is in a charged state.

Furthermore, a heated catalyst may be included in the special load.

[0011]

In the power supply device for a vehicle according to the present invention, the connection state of the plurality of batteries is determined according to the load state of the special load and whether or not the power source unit for the special load is in the charged state. When power is supplied to the battery, all of the plurality of batteries can be connected in series to make the output voltage of the special load power supply unit a high voltage, so that the load current of the special load can be reduced. As a result, the diameter of the electric wire for supplying the electric current to the special load can be reduced, and the electric current corrosion effect at the connecting portion of the electric wire can be made inactive due to the small electric current value.

Further, at the time of charging, since the special load power source can be charged at a high voltage by connecting all of the plurality of batteries in series, the charging current can be reduced and the wire diameter of the charging wire can be reduced. it can. Moreover, since it is not necessary to connect the plurality of batteries in parallel, battery connection during charging becomes simple.

Further, when the heated catalyst is included as the special load, the catalytic action of the exhaust purification system can be made normal immediately after the cold start.

Further, when the special load is light or when power supply to the load is not required, the connection state of a plurality of batteries constituting the special load power supply unit is switched to set the supply voltage to the special load to a medium voltage or a low voltage. Since it can be a voltage,
The load current becomes smaller than in the case of high voltage, and the electrolytic corrosion action can be further deactivated.

[0015]

1 is a circuit diagram showing an embodiment of a vehicle power supply device according to the present invention. In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and 4 is a special load such as a quick heater, a heated catalyst, a heated window shield, etc., which is a load requiring a large amount of power. One end of the special load 4 has an electric wire 5a and a switch SW1
And connected to the special load power supply unit 6 via the electric wire 5b,
The other end of the special load 4 is grounded. The plurality of batteries 61 to 64 forming the special load power supply unit 6 are 12 V batteries that supply electric power to the special load 4 and have the same load current value.

One end of the battery 61 is connected to the switch SW1 and the other end is connected to the switch SW3. Further, one end of the battery 62 is connected to the switch SW3, and the other end is connected to the switch SW4. Further, one end of the battery 63 is connected to the switch SW4, and the other end is connected to the switch SW5. Further, one end of the battery 64 is connected to the switch SW5, and the other end is grounded. The switches SW3 to SW5 form a connecting unit.

The switches SW1 to SW5 are controlled by an electronic control unit 10 as a control means.

Next, the operation of the circuit shown in FIG. 1 will be described. First, a case where the special load 4 needs to be driven at a high voltage, for example, a case where all the loads forming the special load 4 need to operate at the rated value will be described. in this case,
The electronic control unit 10 includes switches SW3, SW4, S
W5 common terminals 31, 41, 51 and connection terminals 33, 4
The switch SW1 is turned on and the switch SW2 is turned off. As a result, the four batteries 61 to 64 are all connected in series, and a high voltage of 48 V is supplied to the special load 4 via the electric wires 5b and 5a.

As described above, the output voltage VE of the special load power supply unit 6 is set to a high voltage and electric power is supplied to the special load 4, so that the electric wires 5b and 5 are different from those when the VE is set to a low voltage.
The load current flowing through a can be reduced, and the electric wire 5
Since the wire diameters of b and 5a can be reduced, and the load current is small, the electrolytic corrosion action at the wire connection portion can be deactivated.

Next, the operation during charging will be described. The charging is performed by, for example, the output voltage V of the batteries 61 to 64 connected in series.
It is performed when E becomes equal to or less than the target output voltage calculated by the electronic control unit 10. Battery 6 even when charging
1 to 64 are connected in series, and the switch SW2 is controlled by the electronic control unit 10 to be turned on. Also,
The switch SW1 is controlled by the electronic control unit 10 so that it is turned on when power needs to be supplied to the special load 4 and turned off when it is not necessary. Booster 8
Is a voltage Vb obtained by boosting the output voltage Va of the alternator 3.
Is output. The output voltage Vb of the booster 8 is a voltage (for example, 60 V) sufficiently larger than the target output voltage, and the charging current is supplied to the batteries 61 to 64 via the switch SW2.

By charging at a high voltage in this way,
The charging current is reduced, and the wire diameter of the electric wire 5b for supplying the charging current can be reduced. Further, a switch for connecting the batteries 61 to 64 in parallel to perform low voltage charging is not necessary, and the connection of the batteries at the time of charging becomes simple. Although the booster 8 is used in FIG. 1, the booster 8 is not necessary if the output voltage Va of the alternator 3 is sufficiently higher than the target output voltage.

Next, the operation when the special load 4 is a light load, that is, when the supply voltage to the load 4 does not have to be a high voltage will be described. When the special load 4 is a light load, the output voltage of the battery is 24 V or 12 in FIG.
V is all right. When it is set to 24V, the electronic control unit 10
Connects the switch SW3 to the connection terminal 33 and connects the switch SW4 to the connection terminal 42. This allows the battery 6
1 and 62 are connected in series, and the other end of the battery 62 is grounded via the switch SW4. Battery 6 at this time
3 and 64 are not used. On the other hand, when the voltage is 12 V, the electronic control unit 10 connects the switch SW3 to the connection terminal 32. As a result, only the battery 61 is connected to the special load 4, and the batteries 62 to 64 are not used.

As described above, when the special load 4 is a light load, the battery voltage VE is set to the medium voltage (24V) or the low voltage (12V).
V) makes it possible to further reduce the load current and make the electrolytic corrosion action more inactive than in the case of high voltage (48V). Whether the battery voltage VE is low or medium depends on the power required by the load 4.

When the power supply to the special load 4 is unnecessary, the electronic control unit 10 turns off the switch SW1.

The batteries 61 to 64 are connected in series to set the output voltage VE to a high voltage of 48 V in the following cases (1) and (2), for example. (1) Within 120 seconds immediately after a cold start, even one switch of special electrical equipment (special electrical load) 4 is turned on, and all three conditions of the engine water temperature being below the predetermined water temperature are satisfied (2) Vehicle speed is 30 km When it is necessary to charge at / h to 80 Km / h Next, the output voltage VE is set to the medium voltage of 24 V or the low voltage of 12 V in the following cases (3) to (10), for example. (3) Under the conditions of (1), 120 immediately after the cold start.
When seconds are exceeded (4) When all the switches of special electrical equipment (special load) 4 are off (5) When the engine water temperature exceeds the specified water temperature (6) When the intake air temperature exceeds the specified temperature ( 7) When the temperature of the heated catalyst exceeds a predetermined temperature (8) When the trunk or bonnet is opened (9) When deterioration of the battery is detected (10) When the ignition key is off (when the engine is stopped)

[0026]

As described above, in the power supply device for a vehicle according to the present invention, when power is supplied to the special load, all the plurality of batteries are connected in series so that the output voltage of the power supply unit for the special load is adjusted. Since high voltage can be used, the load current to the special load can be reduced, the diameter of the wire for supplying the current to the special load can be made thin, and compared to the case of supplying power at a low voltage. The small electric current value makes it possible to make the electrolytic corrosion action in the connection portion of the electric wire inactive.

When all of the plurality of batteries are connected in series at the time of charging, the special load power source unit can be charged at a high voltage, so that the charging current can be reduced and the wire diameter of the charging wire can be reduced. .. In addition, since it is not necessary to connect the plurality of batteries in parallel for low voltage charging, battery connection during charging is simplified, and if the power to be supplied to the load may be small, a special load may be used. Since the output voltage of the power supply unit can be lowered, the load current can be further reduced as compared with the case where the output voltage is high, and the electrolytic corrosion action can be made inactive.

Further, when the heated catalyst is included in the special load, the catalytic action can be made normal immediately after the cold start.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a vehicle power supply device according to the present invention.

FIG. 2 is a circuit diagram showing a conventional example of a power supply device for a vehicle.

[Explanation of symbols]

 1 Power Supply Unit for Normal Load 2 Normal Load 3 Alternator 4 Special Load 5a, 5b Electric Wire 6 Power Supply Unit for Special Load 7 Electronic Control Unit 8 Booster 61-64 Battery SW0-SW5 Switch

Claims (3)

[Claims] 1. A power supply for a vehicle having a normal load power supply unit for supplying power to a normal load and a special load power supply unit for supplying power to a special load, which is composed of a plurality of batteries having the same load current value. In the device, connection means for determining a connection state of the plurality of batteries depending on whether the load state of the special load and the power supply unit for the special load are in a charging state, and the load state of the special load and the special load A power supply device for a vehicle, comprising: a control unit that detects whether or not the power supply unit is in a charged state and controls the connecting unit. 2. The control means controls the connecting means so as to connect all of the plurality of batteries in series when the special load power supply unit is in a charged state. The vehicle power supply described. 3. The power supply device for a vehicle according to claim 1, wherein the load state of the special load is a state in which at least a heated catalyst is a load.