JPH10184506A - Vehicular power source device using electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vehicular power source device using an electric double layer capacitor which can improve startability of an engine, and structure an electric system suitable for kinds of electric loads. SOLUTION: Power generation is executed by an alternator 10 with a high voltage value in an area where an engine speed at the starting is lower than a specified value. In addition, relay switches 34a, 34b are opened to separate a lead battery 24 from the alternator 10. High voltage charging is carried out only to an electric double layer capacitor 14. A starter motor 18 can be driven by the current of the high voltage value from the electric double layer capacitor 14. The alternator 10 performs power generation with a normal voltage value at the time of completion of starting where the engine speed exceeds the specified value. In addition, the relay switches 34a, 34b are closed to connect the lead battery 24 to the alternator 10.

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 a vehicle using an electric double layer capacitor, and more particularly to a power supply device for a vehicle which has both an electric double layer capacitor and a lead storage battery, and supplies current to an electric load mounted on the vehicle from both. The present invention relates to a power supply device for a vehicle.

[0002]

2. Description of the Related Art As shown in FIG. 7, a lead-acid battery is used in an automobile engine to drive various accessories such as a fan and a pump, or to drive a starter motor for cranking at the time of starting. A vehicle power supply device including a motor generator 100 and an alternator 102 serving as a vehicle-mounted generator is provided. The alternator 102 generates electric power by the engine rotational force.
00 and various electrical loads. The alternator 102 includes an IC regulator for stabilizing the generated voltage. Further, the power generation voltage is adjusted so that the lead storage battery 100 is always in the optimal charging state (a state satisfying the float charging condition).

On the other hand, the lead storage battery 100 has a high energy density and can be used for a relatively long time. But,
Since the lead storage battery 100 is a battery with a chemical change,
Even if the voltage is controlled so as to be in an optimal state of charge, the deterioration is apt to progress when charge and discharge are repeated, and the charging time is long, and it is necessary to replenish the electrolyte.

In recent years, various proposals have been made to use the electric double layer capacitor 110 as a battery instead of the lead storage battery 100 as shown in FIG. This electric double layer capacitor 110 is a device in which the capacitance is drastically increased by using an insulating film formed at an interface between an electrode and an electrolytic solution, and generates a voltage of, for example, about 2.5 V in a single cell. I do. Therefore, when used as a power supply device for a vehicle, a plurality of capacitor cells are connected in series so that a desired output voltage can be obtained.

[0005]

In the power supply device for a vehicle using the electric double layer capacitor 110 as described above, since the electric double layer capacitor 110 is a battery which does not involve a chemical change, maintenance such as replenishment of an electrolyte is not required. In addition, the characteristic that the life is long can be obtained. However, the electric double layer capacitor 110 also has the property that the power density is higher but the energy density is much lower than that of the lead storage battery 100.

Therefore, when the vehicle is left for a long time after the engine is stopped, the electric double layer capacitor 110 is not used.
, The rate of voltage drop due to self-discharge becomes larger than that of the lead storage battery 100. For this reason, energy required to drive the starter motor at the time of restart is stored in the electric double layer capacitor 1.
10 may not be available. In addition, since a large current is required to drive the starter motor, when the cranking time becomes long, for example, during a cold start, the energy required for cranking can be sufficiently supplied from the electric double layer capacitor 110. It may be impossible to supply.

In order to solve the problem caused by such low energy density, a method of increasing the capacitance of the electric double layer capacitor 110 and storing electric energy enough to cover long-time cranking may be considered. However, when the capacitance of the electric double layer capacitor 110 is simply increased, the outer diameter and the volume of the electric double layer capacitor 110 are much larger than those of the lead storage battery 100.
Therefore, in this case, it is not possible to reduce the size and weight of the vehicle power supply device utilizing the high power density of the electric double layer capacitor 110.

On the other hand, since the energy density of the electric double layer capacitor 110 is low, when a certain electric load consumes a large amount of current, the electric double layer capacitor 110
, There is a possibility that the voltage between both ends (output voltage) may drop sharply. For example, when the electric double layer capacitor 110 supplies a large current to drive a starter motor, the supply voltage from the electric double layer capacitor 110 to other electric loads suddenly drops. Therefore, this voltage drop may cause, for example, the engine control unit to be in a reset state, causing a problem in the fuel supply control. That is, when a single power source having a low energy density called the electric double layer capacitor 110 uniformly supplies current to various electric loads, a voltage drop of the electric double layer capacitor 110 caused by driving the starter motor is reduced. There is a risk that other electrical loads will be adversely affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described various problems. An object of the present invention is to store high electric energy in an electric double-layer capacitor, thereby improving the startability of an engine and the like. It is an object of the present invention to provide a power supply device for a vehicle using an electric double-layer capacitor capable of constructing a power supply system suitable for a type of dynamic load.

[0010]

In order to achieve the above object, a vehicle power supply device using an electric double layer capacitor according to the first aspect of the present invention sets the charging voltage to the electric double layer capacitor higher than that of a lead storage battery. Accordingly, a large amount of electric energy can be stored in the electric double layer capacitor. That is, the on-vehicle generator charges the lead storage battery at a normal voltage value, and charges the electric double-layer capacitor at a higher voltage value higher than the normal voltage value. The current is supplied to an electric load smaller than the electric load supplied from the double-layer capacitor, and the electric load supplied from the electric double-layer capacitor is larger than the electric load supplied from the lead storage battery. Each connection is made to supply current to an electrical load.

As described above, by separately forming the two power supply systems, the power supply system on the lead storage battery side and the power supply system on the electric double-layer capacitor side, a large electric load is activated to operate the electric double-layer capacitor. The drop in voltage does not affect small electrical loads that are powered by lead-acid batteries. Further, since the electric double layer capacitor is charged by a high voltage value which is higher than a normal voltage value, a large amount of electric energy can be stored. Therefore, a large electric load can be reliably operated by the high voltage value. In addition, by storing a large amount of electric energy, the electric energy can be retained even when the vehicle is left for a long period of time, and a large amount of electric energy can be stored while reducing the outer diameter and volume of the electric double layer capacitor. It is also possible to store.

Also, in the power supply device according to the second aspect, the electric double layer capacitor supplies a current to the starter motor at a high voltage value, so that a large current required by the starter motor can be supplied for a long time. By driving the motor at a high speed, the startability of the engine can be improved.

Further, in the power supply device according to the third aspect, the lead storage battery is connected to the output terminal of the vehicle-mounted generator via the switch means, and the electric double layer capacitor is connected to the output terminal of the vehicle-mounted generator via the backflow preventing diode. Connected to. Therefore, if the lead storage battery and the onboard generator are shut off by the switch means, when the onboard generator charges the electric double layer capacitor with a high voltage value, the high voltage current is supplied to the lead storage battery. Can be prevented. In addition, the backflow prevention diode can prevent a high-voltage current from flowing from the electric double-layer capacitor charged with a high voltage to the lead storage battery.

Next, in the power supply device according to the fourth aspect, since the lead storage battery and the electric double layer capacitor are connected via the backflow preventing diode and a resistor having a predetermined resistance, In the charging state, if a voltage drop occurs in the electric double layer capacitor below the voltage between both ends of the lead storage battery, charging of the electric double layer capacitor from the lead storage battery is performed appropriately. Further, since the backflow prevention diode is interposed, no current flows from the electric double layer capacitor charged at a high voltage to the lead storage battery.

According to a fifth aspect of the present invention, at the time of starting the engine, when the engine speed is in a range of a speed equal to or less than a predetermined value, the power generation voltage of the vehicle-mounted generator is set to a high voltage value and the switch means is adjusted. To cut off the connection between the lead storage battery and the on-vehicle generator, and when the engine speed is in a rotation speed region exceeding the predetermined value, set the generated voltage of the on-vehicle generator to a normal voltage value and switch the switch means. By providing a control means for adjusting and connecting the lead storage battery and the on-vehicle generator, in a low rotation speed region after starting the engine, while supplying current to a large electrical load from the electric double layer capacitor, The electric double layer capacitor can be charged with a high voltage value.

In the range of the number of revolutions equal to or higher than the predetermined value, the power generation voltage of the vehicle-mounted generator is set to the normal voltage value to charge the lead storage battery, so that the engine load during normal running can be reduced.

Further, in the power supply device according to claim 6, the control means does not immediately perform voltage switching even when the engine speed enters a rotation speed region exceeding a predetermined value, and waits for a predetermined time to elapse. The power generation voltage of the on-vehicle generator is switched from the high voltage value to the normal voltage value, and the lead storage battery and the on-vehicle generator are connected. Thereby, the electric double layer capacitor can be charged more sufficiently.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a circuit configuration of a vehicle power supply device using an electric double layer capacitor according to a first embodiment of the present invention.

An output terminal of the alternator 10 as an “in-vehicle generator” for generating electric power by using the engine torque is connected to a positive terminal of an electric double layer capacitor 14 via a connection line 12. The alternator 10 includes an IC regulator 64 described with reference to FIG. The generated voltage of the alternator 10, that is, the charging voltage is controlled by controlling the pulse current supplied to the field coil, so that the high voltage value VH of 24V and 12.7V
The normal voltage value VN can be switched in two stages. In addition, electric double layer capacitor 1
4 is configured by connecting a plurality of capacitor cells in series.

A backflow preventing diode 16 is provided between the alternator 10 and the electric double layer capacitor 14. The output terminal of the alternator 10 is connected to the anode of the diode 16 and the electric double layer capacitor 1
4 is connected to the cathode of the diode 16.

The positive terminal of the starter motor 18 as a "large electric load" is a normally open starter switch 2
0 is connected to the positive terminal of the electric double layer capacitor 14. That is, from the connection line between the diode 16 and the electric double layer capacitor 14, the connection line 2
The starter switch 20 and the starter motor 18 are provided on the connection line 22.

The positive terminal of the lead storage battery 24 is connected to the output terminal of the alternator 10 and the anode of the diode 16 via the connection lines 26 and 12. Furthermore, it is connected to an electric load 30 as a “small electric load” via another connection line 28. The electric load 30 is a small electric load that is vulnerable to power supply voltage fluctuations of a microcomputer system or the like, such as a control device 40 described later. A key switch 32 is provided in the middle of the connection line 28. Therefore, when the key switch 32 is closed and turned on, the electric load 30 is turned off.
Is connected to the lead storage battery 24 via the connection line 28, and to the output terminal of the alternator 10 and the anode side of the diode 16 via the connection lines 28, 26 and 12.

In the middle of the connection line 26 connecting the lead storage battery 24 and the connection line 12, a relay switch 34 as "switch means" is provided. The relay switch 34 includes a normally closed relay contact 34a provided in the middle of the connection line 26, and an electromagnetic coil 34b for opening and closing the relay contact 34a by electromagnetic force.

One terminal of the electromagnetic coil 34b is
Connection line 2 between the lead storage battery 24 and the relay contact 34a
6 and the other terminal of the electromagnetic coil 34 b is connected to the control device 40. In a non-energized state in which no current flows through the electromagnetic coil 34b, the relay switch 34 closes the relay contact 34a and the alternator 10
Is connected to the lead storage battery 24, and when a current flows through the electromagnetic coil 34b, the relay contact 34a is opened to cut off the connection between the alternator 10 and the lead storage battery 24.

The lead storage battery 24 and the alternator 10 are connected not only through the connection line 26 and the like but also through the connection line 36. That is, the connection line 36 is provided in parallel with the relay switch 34 so as to bypass the connection line 26. A supplemental charging resistor 38 is provided in the connection line 36.

When the voltage between both ends of the electric double layer capacitor 14 becomes lower than the voltage between both ends of the lead storage battery 24 when the vehicle is left for a long period of time, the electric double layer is connected to the electric double layer capacitor 24 via the connection line 36 and the resistor 38. A supplementary current is supplied to the capacitor 14. Then, the voltage across the electric double layer capacitor 14 is maintained at the voltage across the lead storage battery 24 by the supplementary current. As the value of the resistor 38 decreases, a larger replenishment current flows, and the voltage of the electric double layer capacitor 14 recovers to the voltage of the lead storage battery 24 in a short time.
Increases, the supplementary current decreases and the voltage recovery time of the electric double layer capacitor 14 increases.

On the other hand, when the value of the resistor 38 is reduced, when the alternator 10 generates power with the high voltage value VH,
This high voltage value VH may be applied to the lead storage battery 24. Therefore, in order to keep the voltage between both ends of the electric double layer capacitor 14 at the both ends of the lead storage battery 24 when the engine is stopped for a long time, the minimum replenishing current is set to a relatively large value to prevent this. Is supplied to the electric double layer capacitor 14, the value of the resistor 38 is determined.

A control device 40 as "control means"
Includes a crank angle sensor 4 for detecting an engine speed N.
2 is input.

Next, an example of an internal circuit of the control device 40 will be described with reference to FIG. The control device 40 includes a discriminator 50 to which the engine speed N from the crank angle sensor 42 is input, a time constant circuit 52 that outputs a transistor drive signal in accordance with a switching signal output from the discriminator 50, And a transistor 54 controlled by the output from the circuit 52.

The discriminator 50 outputs an "L" level signal when the engine speed N is lower than the predetermined value NT shown in FIG. 3, and when the engine speed N exceeds the predetermined value NT. It outputs an "H" level signal. Here, the predetermined value NT is set as a value for determining whether or not the start of the engine has been completed.

The time constant circuit 52 includes an AND gate 55,
And a NAND gate 56. AND gate 55
Is connected to the output terminal of the discriminator 50,
The second input terminal of the AND gate 54 is connected to the first input terminal. Therefore, when the waveform of the output signal from the discriminator 50 is distorted, the waveform can be adjusted by the AND gate 55.

The first input terminal of the NAND gate 56 is A
The second input terminal of the NAND gate 56 is directly connected to the output terminal of the ND gate 52 and the resistor 58 and the capacitor 6
0 is connected to the output terminal of the AND gate 54. The time constant is determined by the resistance value of the resistor 58 and the capacitance of the capacitor 60.

The output terminal of the NAND gate 56 is connected to the base of the transistor 54 via the base current limiting resistor 62. The collector of the transistor 54 is connected to the electromagnetic coil 34b of the relay switch 34, and the emitter of the transistor 54 is grounded. Therefore,
When the output signal of the NAND gate 56 goes to "H" level, the transistor 54 is turned on, a current flows through the electromagnetic coil 34b, and the relay contact 34a opens. On the other hand, when the output signal of the NAND gate 56 becomes "L" level, the control transistor 54 stops operating, the power supply to the electromagnetic coil 34b stops, and the relay contact 34a closes.

The IC regulator 64 includes the alternator 1
0, the charging voltage (power generation voltage) when charging the electric double layer capacitor 14 or the lead storage battery 24
Is controlled. The output signal of the NAND gate 56 is input to the IC regulator 64. When an “H” level signal is input from the NAND gate 56, the IC regulator 64
The power generation voltage of 0 is set to the high voltage value VH, and when an “L” level signal is input from the NAND gate 56, the power generation voltage of the alternator 10 is set to the normal voltage value VN.

Next, the operation of the present embodiment will be described with reference to FIGS. First, at a certain time t1, when the ignition key is rotated and the starter switch 20 (see FIG. 1) is closed, a current having a voltage of the high voltage value VH is supplied from the electric double layer capacitor 14 to the starter motor 18. . As a result, high-speed cranking is started, and the engine is started.

On the other hand, since the engine speed N at the start is lower than the predetermined value NT, the discriminator 50 outputs an "L" level switching signal. Therefore, an “L” level signal is input to each input terminal of the AND gate 55, and the output signal of the AND gate 54 becomes “L” level. And AN
Since an “L” level signal is input from the output terminal of the D gate 55 to each input terminal of the NAND gate 56, NAN
The output signal of D gate 56 attains "H" level. As a result, the transistor 54 is turned on, the electromagnetic coil 34b is excited, and the relay contact 34a is turned off, that is, opened, and the lead-acid battery 24 in the connection line 26 is turned off.
And the alternator 10 are disconnected. Further, since the output signal of NAND gate 56 is at “H” level, IC regulator 64 sets the generated voltage of alternator 10 to high voltage value VH.

That is, the engine speed N immediately after the start, etc.
Is lower than the predetermined value NT, the relay switch 34
Is released, the charging line to the lead storage battery 24 is disconnected, and the generated voltage of the alternator 10 is set to the high voltage value VH. Accordingly, the electric double layer capacitor 14 is supplied with the current of the high voltage value VH, and at the same time, the cranking is started by the high voltage current. Then, while the engine speed is increasing, the alternator 10 continues to generate the high voltage value VH using the engine torque. Then, the electric double layer capacitor 14 is charged with the high voltage value VH, and the electric energy consumed for cranking is recovered.

Here, the electric energy stored in the electric double layer capacitor 14 is proportional to the square of the capacitance C and the voltage V between both ends. Therefore, when the charging voltage (the voltage V between both ends) is doubled while keeping the capacitance C equal,
The electric energy stored in the electric double layer capacitor 14 is 4
Increase by a factor of two. Conversely, if the charging voltage is doubled, 1
The same electrical energy can be stored with a capacitance of / 4. Therefore, if the charging voltage is doubled, twice the electric energy can be stored even if the capacitance is reduced to half.

When the engine speed N exceeds a predetermined value NT at time t2, the discriminator 50 outputs an "H" level switching signal. As a result, an "H" level signal is output from the output terminal of the AND gate 55,
This "H" level signal is input to the first input terminal of NAND gate 56.

Here, the second input terminal of the NAND gate 56 is connected to the output terminal of the AND gate 55 via the resistor 58 and the capacitor 60. Therefore, the resistance 58
The signal level input to the second input terminal is maintained at “L” during a time until the charging current determined by the capacitor 60 charges the capacitor 60, and is input to the second input terminal when the capacitor 60 is charged. The signal level becomes "H". As a result, at time t3 when the predetermined time Δt has elapsed, an “L” level signal is output from the output terminal of NAND gate 56. When the transistor control signal from the time constant circuit 52 becomes “L” level, the transistor 5
4 is turned off. Then, the power supply to the electromagnetic coil 34b is stopped, the relay contact 34a returns to the closed state, and the lead storage battery 24 and the alternator 10 are connected. Also, IC
Since the signal level input to the regulator 64 also becomes “L”, the generated voltage of the alternator 10 becomes the normal voltage value VN
Is set to

That is, when the engine speed N is equal to the predetermined value NT
When the predetermined time Δt elapses after the time exceeds the limit, the relay switch 34 is turned off, and the lead storage battery 24 and the alternator 10 are connected. Further, the generated voltage of the alternator 10 switches from the high voltage value VH to the normal voltage value VN.
Therefore, the lead storage battery 24 is charged with the normal voltage value VN, and the electric load 30 is energized.

When the engine is stopped, it is in a state before time t1 in FIG. That is, since the engine speed N is “0” and lower than the predetermined value NT, the discriminator 50
Becomes "L", and an "H" level signal is output from NAND gate 56. Therefore, the relay switch 34 is turned on to open the relay contact 34a, and the voltage generated by the alternator 10 is set to the high voltage value VH.

As described above, when the engine is started, the electric double layer capacitor 14 is charged with the high voltage value VH and stores a large amount of electric energy, but the voltage gradually decreases due to self-discharge. Therefore, if the vehicle is left for a long time with the engine stopped,
There is a possibility that the voltage of the electric double layer capacitor 14 drops to near the normal voltage value VN. However, when the voltage of the electric double layer capacitor 14 falls below the normal voltage value VN, a small supplementary current flows into the electric double layer capacitor 14 from the lead storage battery 24 via the resistor 38. Therefore, as long as the lead storage battery 24 stores electric energy, the lead storage battery 24
, The voltage of the electric double layer capacitor 14 is maintained at the normal voltage value VN.

According to the present embodiment configured as described above, the following operation is achieved. First, two types of power supply systems can be independently obtained according to the magnitude of the electric load, and a large amount of electric energy can be stored in the electric double layer capacitor by charging with the high voltage value VH.

Thus, even if a large electric load is activated and the voltage of the electric double layer capacitor 14 is suddenly reduced, the influence of the voltage drop does not affect the power supply system on the lead storage battery 24 side. Therefore, when a large electric load, which requires a large current, such as the starter motor 18, is operated, it is possible to prevent the engine control unit and the like from being reset to prevent a problem such as that fuel injection is not performed. be able to.

Also, by charging the electric double layer capacitor 14 with a high voltage value VH higher than the normal voltage value VN, a large amount of electric energy can be stored in the electric double layer capacitor 14. Therefore, the starter motor 18 can be rotated at a high speed by the high voltage value VH for a relatively long time, and the startability of the engine can be improved.

Further, as described above, the charging voltage is set to the high voltage value V.
H, it is possible to store more electric energy than before while reducing the volume of the electric double layer capacitor 14, and to reduce the size of the entire vehicle power supply device while taking advantage of the characteristics of the electric double layer capacitor 14 having a high power density. It is also possible to reduce the weight.

Next, the power supply system on the lead storage battery 24 side and the power supply system on the electric double layer capacitor 14 side can be easily separated. That is, the lead storage battery 24 and the alternator 10 are cut off by the relay switch 34, and the electric double layer capacitor 14 can be charged from the alternator 10 with the high voltage value VH. It is possible to prevent the current of the high voltage value VH from flowing into the storage battery 24.

In the rotation speed region below the predetermined value NT, while the starter motor 18 is driven by the electric double layer capacitor 14, the energy lost by the electric double layer capacitor 14 can be supplemented. In the higher rotation speed region after the time Δt from the alternator 10, the current can be supplied from the alternator 10 to the lead storage battery 24 and the small electric load 30. Therefore, when the engine start is completed, the electric double layer capacitor 14 has the high voltage value VH.
And the engine can be prepared for restarting the engine, and in the subsequent normal running state, the engine load can be reduced and the fuel efficiency can be improved.

Further, the control device 40 controls the engine speed N
Is higher than the predetermined value NT, the electric double layer capacitor 14 is charged with the high voltage value VH for the predetermined time Δt. Therefore, the electric double layer capacitor 14 can be charged with a sufficiently high voltage value VH, and charging for the next engine start can be performed more reliably.

Even when the vehicle is left unattended for a long period of time and the voltage of the electric double layer capacitor 14 drops due to self-discharge, a supplementary current is passed from the lead storage battery 24 to the electric double layer capacitor 14 through the resistor 38, The voltage of the electric double layer capacitor 14 can be maintained at the normal voltage value VN. In particular, since the electric double layer capacitor 14 is charged at the high voltage value VH, the auxiliary storage from the lead storage battery 24 to the electric double layer capacitor 14 is performed until the high voltage value VH decreases to the normal voltage value VN of the lead storage battery 24. Not done. Therefore, the charging burden on the lead storage battery 24 can be reduced as much as possible,
It can withstand long-term vehicle leaving. That is, the potential difference ΔV between the high voltage value VH and the normal voltage value VN serves as a margin for supplementary charging.

In the present embodiment, as shown in FIG. 2, the control device 40 is constituted as a relatively simple electronic circuit including the discriminator 50, the time constant circuit 20, and the transistor 54. The circuit can be easily incorporated into the IC regulator 64.

Next, a second embodiment of the present invention will be described with reference to FIGS. Note that, in the present embodiment, the same components as those of the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 4 is an overall circuit diagram of the vehicle power supply device according to the present embodiment. As will be described later, the control device 70 according to the present embodiment uses software to generate the voltage of the alternator 10 and the relay. The open / close state of the switch 34 is controlled. In addition to the crank angle sensor 42, a capacitor voltage detector 72 for detecting the voltage VC across the electric double layer capacitor 14 is connected to the controller 70.

FIG. 5 is a specific block diagram of the control device 70. The control device 70 includes an input interface 70a for receiving a signal from each sensor and an output interface 7 for outputting a drive control signal to each member.
0b, CPU 70c as a main processing unit, ROM 70 for storing control programs and preset fixed data
d, RAM 70e for storing detection signals and the like from each sensor
Are connected to each other by a bus line 70f.

As functions in the CPU 70c, an engine speed determining unit 73 for determining whether or not the engine speed N is equal to or lower than a predetermined value NT, and the voltage VC of the electric double layer capacitor 14 is changed to a high voltage value VH. And a drive controller 7 that outputs a control signal for controlling the relay switch 34 and the alternator 10 according to the determination result of each of the determiners 73 and 74.
6 are provided.

Next, the operation of the present embodiment will be described. The flowchart of FIG.
A process for controlling the switching between the power supply system on the 4th side and the power supply system on the lead storage battery 24 side is shown in step (hereinafter simply referred to as “S”).
In step 201, the state of the key switch 32 is read, and in step S202, it is determined whether the key switch 32 has been turned on. If the key switch 32 is on (YES), the engine speed N is read from the crank angle sensor 42 in S203.

Next, in S204, it is determined whether or not the engine speed N is equal to or less than a predetermined value NT. If the engine speed N is equal to or lower than the predetermined value NT (YES), the start of the engine is not completed, so the relay contact 34a of the relay switch 34 is opened to connect the lead storage battery 24 and the alternator 10 in S205. Is cut off, and the generated voltage of the alternator 10 is set to the high voltage value VH in S206.

Therefore, in this state, the starter switch 20
Is turned on, a current having a high voltage value VH flows from the electric double layer capacitor 14 to the starter motor 18, and the starter motor 18 starts rotating and cranking is performed. Then, when the engine is started, the alternator 10 uses the engine torque at the time of the start to generate the high voltage value VH.
To generate electricity. Thereby, the electric double layer capacitor 14 is charged again with the high voltage value VH.

On the other hand, if "NO" is determined in S204, this means that the engine speed N has exceeded the predetermined value NT and the engine has been started. Then, the next S20
At 7, the voltage VC of the electric double layer capacitor 14 detected by the capacitor voltage detecting section 72 is compared with the high voltage value VH to determine whether or not the charging of the electric double layer capacitor 14 with the high voltage value VH is completed. . If the capacitor voltage VC does not reach the high voltage value VH, it means that the charging of the electric double layer capacitor 14 has not been completed yet.
Is determined as NO, and the process returns to S204.

When the capacitor voltage VC has reached the high voltage value VH (YES), the charging of the electric double layer capacitor 14 has been completed. Therefore, the process proceeds to S208, in which the relay switch 34 is closed and the lead-acid battery 2
4 and the alternator 10 are connected. At the same time, S
In 209, the generated voltage of the alternator 10 is set to the normal voltage value VN. As a result, the current having the normal voltage value VN generated by the alternator 10 is supplied to the lead storage battery 24 and the electric load 30.

According to the present embodiment having such a configuration, the same effect as that of the first embodiment can be obtained.
In addition to this, the present embodiment further exerts the following effects.

First, after confirming that the electric double layer capacitor 14 has been charged with the high voltage value VH, it is possible to switch to the power supply system using the lead storage battery 24.

Next, the control contents of the control device 70 are shown in FIG.
As shown in the figure, the configuration is realized by software.
Control contents can be easily added and modified. For example, S20
In place of the voltage determination by step 7, as in the first embodiment, a configuration may be adopted in which charging of the electric double layer capacitor 14 is considered to be completed when a predetermined time Δt has elapsed.

It should be noted that the present invention is not limited to the configuration of each of the above embodiments, and various changes can be made within the scope of the present invention. For example, in each of the above-described embodiments, a case where a normally closed relay switch is used as the relay contact 34a is illustrated. Instead, a relay switch having a normally open relay contact may be used. In this case, the elements such as the transistor shown in FIG. 2 are also changed so that the switching of the relay switch is reversed.

[0066]

As described above, according to the power supply apparatus for a vehicle using the electric double layer capacitor according to the present invention, the power supply system on the lead storage battery side and the power supply system on the electric double layer capacitor side are provided. Because an independent power supply system can be obtained, even if a large electric load is activated and the voltage of the electric double layer capacitor suddenly drops, the effect will affect the small electric load controlled by the lead-acid battery. There is no. Further, since the electric double layer capacitor is charged with a high voltage value higher than the normal voltage value, a large amount of electric energy can be stored. Therefore, a large electric load can be reliably operated, electric energy can be held for a long time, and the outer diameter and volume of the electric double layer capacitor can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic circuit configuration diagram of a vehicle power supply device using an electric double layer capacitor according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a main part of a specific circuit of the control device.

FIG. 3 is a characteristic diagram showing an operation state of a relay switch and a generated voltage of an alternator according to a change in an engine speed.

FIG. 4 is a schematic circuit configuration diagram of a vehicle power supply device using an electric double layer capacitor according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing an internal configuration of a control device.

FIG. 6 is a flowchart for controlling an operation state of a relay switch and a generated voltage of an alternator based on an engine speed.

FIG. 7 is a schematic circuit configuration diagram showing a main part of a vehicle power supply device using a lead storage battery according to a conventional technique.

FIG. 8 is a schematic circuit diagram showing a main part of a vehicle power supply device using an electric double layer capacitor according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Alternator 14 Electric double layer capacitor 16 Diode for backflow prevention 18 Starter motor 24 Lead storage battery 30 Electric load 34 Relay switch 38 Resistance for auxiliary charging 40 Control device 70 Control device

Claims (6)

[Claims] 1. A vehicle power supply device having an electric double layer capacitor and a lead storage battery charged by an onboard generator and supplying current to various electric loads mounted on the vehicle, wherein the onboard generator comprises: The generation voltage is adjustable, the lead storage battery is charged at a normal voltage value, and the electric double layer capacitor is charged at a high voltage value higher than the normal voltage value. The current is supplied to an electric load smaller than the electric load supplied from the electric double layer capacitor, and the electric load supplied from the lead storage battery to the electric load from the electric double layer capacitor. Connection between the lead storage battery and the electric double layer capacitor and the onboard generator, and the lead storage battery and the electric double layer so as to supply a current to a larger electric load. Vehicle power supply device using an electric double layer capacitor, characterized in that said a capacitor is connected between the electrical load has been performed. 2. The power supply device for a vehicle using an electric double layer capacitor according to claim 1, wherein the electric double layer capacitor supplies a current to a starter motor with the high voltage value. 3. The lead-acid battery is connected to an output terminal of the vehicle-mounted generator via switch means, and the electric double-layer capacitor is connected to an output terminal of the vehicle-mounted generator via a backflow prevention diode. A vehicle power supply device using the electric double-layer capacitor according to claim 1. 4. The electric double layer according to claim 3, wherein the lead storage battery and the electric double layer capacitor are connected via the backflow preventing diode and a resistor having a predetermined resistance value. Power supply device for vehicles using capacitors. 5. When starting the engine, if the engine speed is in a speed range below a predetermined value, the power generation voltage of the on-vehicle generator is set to the high voltage value, and the lead-acid battery and the on-vehicle generator are set. Control of the generated voltage and control of the switch means so as to cut off the power generation voltage of the vehicle-mounted generator when the engine speed is in a rotation speed region exceeding the predetermined value. And control means for controlling the generated voltage and the switch means so as to set the lead storage battery and the on-vehicle generator in a connected state. A power supply device for a vehicle using the electric double-layer capacitor according to any one of the above. 6. The control means, when the engine rotation speed enters a rotation speed region exceeding the predetermined value, waits for a lapse of a predetermined time, and changes the generated voltage of the vehicle-mounted generator from the high voltage value to the normal voltage. The power supply device for a vehicle using an electric double layer capacitor according to claim 5, wherein the power supply is switched to a value and the lead storage battery and the on-vehicle generator are connected.