JP3972906B2 - Vehicle power supply system - Google Patents

Description

  The present invention relates to a vehicle power supply system including two batteries (main power supply and sub power supply) having different nominal voltages.

Conventionally, regarding the two-battery system, for example, there are known techniques described in Patent Document 1 and Patent Document 2.
Patent Document 1 includes a main power storage unit and a backup power storage unit connected via a DC / DC converter, charges regenerative energy (electric power) obtained during deceleration to the backup power storage unit, and decelerates the charged power. The DC / DC converter is switched and controlled so that it is supplied to the vehicle electrical load in preference to the main power storage means at times other than the time (acceleration, steady running, idling, etc.).

In Patent Document 2, an on-board power supply network battery connected to a generator and a starter battery connected to a starter are provided, both of which are a DC / DC converter and a switch provided in parallel with the DC / DC converter. And connected through.
JP-A-6-296332 JP 2001-186687 A

However, the known technique of Patent Document 1 has the following problems.
a) Since the regenerative energy generated by the alternator at the time of deceleration is charged to the reserve power storage means via the DC / DC converter, the recovery efficiency is deteriorated and the fuel consumption is reduced.
b) Since the operating voltage of the DC / DC converter is applied from the main power storage means, when the main power storage means does not function (for example, when the battery runs out), not only can energy recovery during deceleration be performed, but also reserve power storage. Since it is impossible to supply power from the means to the electric load, the reliability of the system is greatly impaired.

Further, the known technique of Patent Document 2 has the following problems.
c) Since the power generated by the generator is supplied to the starter battery via the DC / DC converter, energy efficiency is deteriorated.
d) When generating a large output (for example, regenerative power generation when the vehicle decelerates) with the generator, a large voltage fluctuation is applied to the onboard power supply network battery and the electric load. Cause a malfunction.
e) Which of the installed power supply network battery and starter battery is used for important equipment (for example, safety equipment such as an electric brake device and an electric power steering device) among electric loads mounted on a vehicle that is required to stably secure electric power. No safety measures are taken when either of them fails. For example, when the on-board power supply network battery is shorted to the ground side, the on-board power supply network battery cannot be separated and power can be supplied from the starter battery to the important device.

  The present invention has been made based on the above circumstances, and an object thereof is to provide a highly reliable vehicle power supply system that can efficiently recover regenerative energy during deceleration and can supply a stable voltage to an electric load. There is to do.

(Invention of Claim 1)
The vehicle power supply system of the present invention includes a generator mounted on a vehicle, a main power supply to which a general load such as lamps and an audio device is connected, and kinetic energy such as deceleration or exhaust connected to the generator. Recovery of regenerative power generated by a generator using thermal energy such as heat, a sub power source for storing the power generated by the generator, a sub power source, a main power source, and a general load via a DC / DC converter A first power supply circuit to be connected, a second power supply circuit for connecting the sub-power supply, the main power supply, and the general load via a switch in parallel with the first power supply circuit, a DC / DC converter, and a switch Control means for controlling the operation, the control means starting the DC / DC converter and opening the switch, or the first control state for opening the switch or stopping the DC / DC converter and closing the switch Wherein the two control states are selectable.

According to said structure, since regenerative energy can be directly collect | recovered by a sub-power supply, without going through a DC / DC converter from a generator, energy recovery can be performed efficiently. The main power supply is charged from the sub power supply via the first power supply circuit or the second power supply circuit (that is, the main power supply is not directly connected to the generator). For example, regenerative power generation during vehicle deceleration is performed. When performing with a generator, a large voltage fluctuation is not added to the main power supply, and stable power supply can be performed to the electric load connected to the main power supply.
Further, since the control means can select the first control state and the second control state in accordance with the running state of the vehicle, the charging state of the main power source and the sub power source, etc., the sub power source is switched to the main power source or the main power source. The charging efficiency from the secondary power source to the secondary power source can be increased.

(Invention of Claim 2)
The vehicle power supply system of the present invention includes a generator that is driven by an engine to generate power, a main power source to which a general load such as a lamp or an audio device is connected, and a generator that is connected to the generator when the vehicle decelerates. A first power supply circuit that connects a sub power source that collects regenerative power that is generated and stores the generated power of a generator that is generated by driving the engine, and the sub power source, the main power source, and a general load via a DC / DC converter. And a second power feeding circuit for connecting the sub power source, the main power source and the general load via a switch in parallel with the first power feeding circuit, and a control means for controlling the operation of the DC / DC converter and the switch. This control means selects the first control state for starting the DC / DC converter and opening the switch, or the second control state for stopping the DC / DC converter and closing the switch. Characterized in that it is a capability.

According to said structure, since the regenerative energy at the time of vehicle deceleration can be directly collect | recovered from a generator to a secondary power supply without going through a DC / DC converter, energy recovery can be performed efficiently. The main power supply is charged from the sub power supply via the first power supply circuit or the second power supply circuit (that is, the main power supply is not directly connected to the generator). For example, regenerative power generation during vehicle deceleration is performed. When performing with a generator, a large voltage fluctuation is not added to the main power supply, and stable power supply can be performed to the electric load connected to the main power supply.
Further, since the control means can select the first control state and the second control state in accordance with the running state of the vehicle, the charging state of the main power source and the sub power source, etc., the sub power source is switched to the main power source or the main power source. The charging efficiency from the secondary power source to the secondary power source can be increased.

(Invention of Claim 3)
The vehicle power supply system according to claim 1 or 2, wherein the control means can select a third control state that activates the DC / DC converter and closes the switch. For example, when there is no margin in the output capability of the DC / DC converter, the third control state can be selected and power can be supplied from the sub power source to the main power source or from the main power source to the sub power source, thus reducing the thermal effect. it can.

(Invention of Claim 4)
The vehicle power supply system according to any one of claims 1 to 3, wherein the main power supply has a larger nominal voltage or nominal capacity than the sub power supply.
In this case, power can be supplied from the main power source to the sub power source by simply closing the switch. Further, since the voltage of the sub power supply is low, the voltage difference between the power generator and the sub power supply becomes larger than the conventional combination of the generator and the main power supply, and the generated power of the generator can be stored efficiently.

(Invention of Claim 5)
The vehicle power supply system according to any one of claims 1 to 3, wherein the main power supply has a smaller nominal voltage or nominal capacity than the sub power supply.
In this case, if the regenerative power during deceleration is stored in the sub power source, the sub power source has a higher voltage than the main power source, so that the regenerative power can be supplied from the sub power source to the general load simply by closing the switch.

(Invention of Claim 6)
In the vehicle power supply system according to any one of claims 1 to 5,
The main power supply and the sub power supply have a region where the operating voltages are substantially the same.
As a result, when some power source fails, it is easy to ensure the redundancy of the power source, and the safety of the vehicle by the power source system can be improved. In addition, when the second control state is selected and power is exchanged between the main power supply and the sub power supply, voltage fluctuation due to a voltage difference at the time of switch ON / OFF can be suppressed. In addition, by combining two power supplies with a small voltage difference (main power supply and sub power supply) that have regions where the operating voltages are substantially the same, for example, when a series regulator is used in a DC / DC converter The voltage can be stepped up and down by the series regulator (because the voltage difference is small and the heat loss is small), and the power supply system can be configured at low cost. The reason why the cost can be reduced is that, as compared with a generally known switching type DC / DC converter, it is not necessary to deal with a reactor for reducing power source noise, and the configuration is simplified.

(Invention of Claim 7)
The vehicle power supply system according to any one of claims 1 to 6, wherein the main power supply is superior in discharge characteristics at a low temperature than the sub power supply.
Needless to say, when the starter is connected to a main power source having excellent discharge characteristics at low temperatures, engine startability at low temperatures is improved.

(Invention of Claim 8)
The vehicle power supply system according to any one of claims 1 to 7, wherein the sub power supply is more excellent in charge acceptance than the main power supply and is easy to detect a state.
Thereby, energy recovery at the time of vehicle deceleration can be performed efficiently.

(Invention of Claim 9)
9. The vehicle power supply system according to claim 1, wherein the main power source is a lead battery, a Li ion battery, or a Ni hydrogen battery, and the sub power source is a lead battery, a Li ion battery, or Ni. It is a hydrogen battery or an electric double layer capacitor.

When lead batteries are used for the main power supply and the sub power supply, respectively, it is possible to reduce costs and achieve both energy recovery during deceleration and stable power supply to a general load.
Further, when a Li ion battery or a Ni hydrogen battery is used as the main power source, it is possible to improve the life of the entire power supply system.
In addition, when a Li ion battery, a Ni hydrogen battery, or an electric double layer capacitor is used as the sub power source, the regenerative capability at the time of deceleration can be improved and the charge acceptability is also excellent.

(Invention of Claim 10)
In the vehicle power supply system according to any one of claims 1 to 3 and 5 to 9,
When power is supplied from the sub power source to the main power source and the general load, the control means selects the second control state when the voltage of the sub power source is reduced to a voltage lower than the allowable rated voltage of the general load. Features.
In this case, power can be supplied by an efficient switch (second power supply circuit) without applying stress to the general load.

(Invention of Claim 11)
The power supply for a vehicle according to any one of claims 1 to 10, wherein the amount of power supplied from the sub power source to the main power source and the general load or the amount of power supplied from the main power source to the sub power source and the general load is supplied. When called an amount, the control means selects one of the first control state and the second control state according to the amount of power supply.
Since the characteristics of the DC / DC converter and the switch differ depending on the amount of power supply (there are orientations and non-directions), by selecting one of the first control state and the second control state according to the power supply amount Can be optimized.

(Invention of Claim 12)
12. The vehicle power supply system according to claim 11, wherein the control means selects the first control state when the power supply amount is equal to or smaller than a predetermined value, and selects the second control state when the power supply amount is larger than the predetermined value. It is characterized by doing.
By using the DC / DC converter only when the power is low (when the power supply amount is a predetermined value or less), it is possible to reduce the cost by reducing the capacity of the DC / DC converter more expensive than the switch. Further, when the power is high (when the power supply amount is larger than a predetermined value), the power supply efficiency can be improved by using a switch.

(Invention of Claim 13)
The vehicle power supply system according to any one of claims 1 to 9, wherein the control means selects one of the first control state and the second control state according to a voltage difference between the main power supply and the sub power supply. It is characterized by selecting.
In this case, the states of the main power supply and the sub power supply can be detected only by the voltage, and an appropriate control state can be selected according to the detected voltage difference between the two power supplies.

(Invention of Claim 14)
14. The vehicle power supply system according to claim 13, wherein the control means selects the second control state when the voltage difference between the main power supply and the sub power supply is equal to or less than a predetermined value, and the voltage difference between the main power supply and the sub power supply is The first control state is selected when larger than a predetermined value.
When the voltage difference between the two power supplies is large, the DC / DC converter steps up and down to supply power with a small voltage difference. When the voltage difference between the two power supplies is small, an efficient switch (second power supply circuit) is used. Can be supplied.

(Invention of Claim 15)
The power supply for vehicles according to any one of claims 1 to 9, wherein the amount of power supplied from the sub power source to the main power source and the general load, or the amount of power supplied from the main power source to the sub power source and the general load is supplied. When calling the quantity, the control means selects one of the first control state and the second control state according to the voltage difference between the main power supply and the sub power supply and the power supply amount. To do.
A more optimal control state can be selected by selecting the control state based not only on the power supply amount or on the power supply amount but also on both the voltage difference between both power sources and the power supply amount.

(Invention of Claim 16)
16. The vehicle power supply system according to claim 15, wherein the control means is configured such that when the voltage of the sub power supply is higher than the voltage of the main power supply and the amount of power supplied from the sub power supply to the main power supply and the general load is greater than a predetermined value. First, the first control state is selected, and after the voltage of the sub power supply is lowered to the allowable rated voltage of the general load or lower, the first control state is switched to the second control state. In this case, an overvoltage is not applied to an electric load such as a light, and the life reduction of the electric load can be suppressed. In addition, the switch can efficiently supply power.

(Invention of Claim 17)
17. The vehicle power supply system according to any one of claims 1 to 16, wherein a third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from a sub power source and a fourth power that feeds the important load from the main power source. The third power supply circuit and the fourth power supply circuit are each provided with a diode for preventing a backflow of the current flow.

  According to this configuration, the redundancy of the power source for the important load can be ensured, so that even if one of the main power source and the sub power source fails, the power can be reliably supplied to the important load. Safety is improved. In addition, by providing the diodes in the third power supply circuit and the fourth power supply circuit, the backflow of the energized current can be reliably prevented, so that stable power supply to the important load can be secured.

(Invention of Claim 18)
A power supply system for a vehicle according to any one of claims 1 to 4 or 6 to 16, wherein a third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from the auxiliary power source to the important load from the main power source And a fourth power supply circuit for supplying power, and when the main power supply has a nominal voltage or nominal capacity larger than that of the sub-power supply, the third power supply circuit is provided with a diode for preventing a reverse current flow. Features.

  According to this configuration, the redundancy of the power source for the important load can be ensured, so that even if one of the main power source and the sub power source fails, the power can be reliably supplied to the important load. Safety is improved. In addition, by providing a diode in the third power supply circuit, it is possible to prevent a conduction current from flowing back from the main power supply, which has a higher nominal voltage than the sub-power supply, to the third power supply circuit, thus ensuring stable power supply to the critical load. it can. Furthermore, since the diode is provided only in the third power feeding circuit, the number of diodes can be reduced as compared with the configuration of claim 16 (the diode is provided in both the third power feeding circuit and the fourth power feeding circuit). In addition, the cost can be reduced, and when power is supplied from the main power source to the important load, it is possible to perform efficient power supply without receiving a loss for the diode.

(Invention of Claim 19)
A power supply system for a vehicle according to any one of claims 1 to 3 or 5 to 16, wherein a third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from the auxiliary power source to the important load from the main power source And a fourth power supply circuit for supplying power, and when the main power supply has a nominal voltage or nominal capacity smaller than that of the sub power supply, the fourth power supply circuit is provided with a diode for preventing a backflow of the energization current. Features.

  According to this configuration, the redundancy of the power source for the important load can be ensured, so that even if one of the main power source and the sub power source fails, the power can be reliably supplied to the important load. Safety is improved. In addition, by providing a diode in the fourth power supply circuit, it is possible to prevent an energizing current from flowing backward from the sub-power supply having a higher nominal voltage than the main power supply to the fourth power supply circuit, thus ensuring a stable power supply to the critical load. it can. Furthermore, since the diode is provided only in the fourth power feeding circuit, the number of diodes can be reduced compared to the configuration of claim 16 (the diode is provided in both the third power feeding circuit and the fourth power feeding circuit). In addition, the cost can be reduced, and when power is supplied from the secondary power source to the important load, it is possible to perform efficient power supply without receiving a loss for the diode.

(Invention of Claim 20)
20. The vehicle power supply system according to any one of claims 17 to 19, wherein when one of the main power supply and the sub power supply fails when the control means selects the second control state, the switch It is characterized by opening.
For example, when the main power supply fails (for example, grounding), the failed main power supply and sub power supply can be separated by opening the switch, so that power can be stably supplied from the sub power supply to important loads. , Power supply redundancy for important loads can be secured.

(Invention of Claim 21)
In the vehicle power supply system according to claim 20,
The control means opens the switch when a short circuit occurs between the positive and negative electrodes of the main power supply or the sub power supply.
Thereby, since the main power supply and the sub power supply can be separated, the redundant power supply to the general load can be realized from the normally functioning power supply.

(Invention of Claim 22)
In the vehicle power supply system according to claim 20,
The control means is characterized by opening the switch when the performance of the main power supply is degraded.
Thereby, since the main power supply and the sub power supply can be separated, the redundant power supply from the sub power supply to the general load can be realized.

(Invention of Claim 23)
In the vehicle power supply system according to claim 20,
The control means is characterized in that the switch is opened when the performance of the sub power supply is deteriorated.
Thereby, since the main power supply and the sub power supply can be separated, the redundant power supply from the main power supply to the general load can be realized.

(Invention of Claim 24)
21. The vehicle power supply system according to claim 20, wherein the control means stops the DC / DC converter if one of the main power supply and the sub power supply fails when the first control state is selected. It is characterized by making it.
For example, if the main power supply fails (for example, ground), the DC / DC converter can be stopped to separate the failed main power supply from the sub power supply. It is possible to ensure the redundancy of the power supply for the important load.

(Invention of Claim 25)
25. The vehicle power supply system according to any one of claims 3 to 24, wherein the control means selects the second control state when the switch temperature exceeds a predetermined value when the second control state is selected. To the third control state.
In this case, when the temperature of the switch exceeds a predetermined value, power is supplied in combination with the second power supply circuit having the switch and the first power supply circuit having the DC / DC converter, so that heat generation of the switch can be suppressed. .

(Invention of Claim 26)
The vehicle power supply system according to any one of claims 1 to 25, wherein the general load connected to the main power supply includes an electric load that requires a dark current after the engine is stopped.
Thereby, after an engine stop, electric power can be supplied from a main power supply with respect to the electric load which requires a dark current from a main power supply.

(Invention of Claim 27)
27. The vehicle power supply system according to claim 1, wherein the control means switches from the first control state to the second control state, or switches from the second control state to the first control state. In this case, the control voltage is switched after the output voltage of the DC / DC converter is boosted to a higher voltage or a lower voltage of the main power supply and the sub power supply.
As a result, voltage fluctuations when the control state is switched can be suppressed, so that blinking of lights or the like can be prevented.

(Invention of Claim 28)
28. The vehicle power supply system according to any one of claims 1 to 27, wherein the control means detects a use state such as a temperature or a voltage of the DC / DC converter when the first control state is selected, and When the detected use state exceeds a specified value, the first control state is switched to the second control state.
In this case, since the use state of the DC / DC converter can be suppressed within a specified value, a failure of the DC / DC converter can be prevented and the DC / DC converter can be downsized.

(Invention of Claim 29)
29. The vehicle power supply system according to claim 1, wherein the control means makes the output voltage of the DC / DC converter substantially the same as the output voltage of the generator when the first control state is selected. It is characterized by controlling.
In this case, voltage fluctuations of the main power supply can be suppressed, so that stable voltage supply to the electric load can be realized. Further, the contact arc of the switch provided in the second power supply circuit is small, and the size can be reduced.

(Invention of Claim 30)
29. The vehicle power supply system according to any one of claims 1 to 28, wherein the control means makes the output voltage of the generator substantially the same as the output voltage of the DC / DC converter when the first control state is selected. It is characterized by controlling.
In this case, voltage fluctuations of the main power supply can be suppressed, so that stable voltage supply to the electric load can be realized. Further, the contact arc of the switch provided in the second power supply circuit is small, and the size can be reduced.

(Invention of Claim 31)
31. The vehicle power supply system according to any one of claims 1 to 30, wherein the control means detects charge acceptability of the main power supply from the output state of the DC / DC converter when the first control state is selected. It is characterized by that.
In this case, since it is not necessary to detect the charge acceptability of the main power source with sensors, a low-cost system can be realized.

(Invention of Claim 32)
The vehicle power supply system according to any one of claims 1 to 31, wherein the control means detects the voltage of the sub power supply and the output voltage of the DC / DC converter according to the running state of the vehicle, and based on the detection result. The output of the generator is controlled.
Thereby, the output of a generator can be controlled efficiently according to the running state of the vehicle.

(Invention of Claim 33)
The vehicle power supply system according to any one of claims 1 to 32, wherein an electric load that does not require dark current is supplied from a sub power supply.
For example, it is possible to prevent the main power from being extended and performance degradation by cutting the power of the main power that has occurred during long-term parking or half-doors to the reset allowable load, and dark current is required. The electrical load that is not to be handled is handled by supplying power from the sub power supply.

(Invention of Claim 34)
34. The vehicle power supply system according to claim 33, wherein the electric load that does not require dark current is an electric load such as an ECU that does not have an internal memory, or an electric load such as an ECU that always uses an initial constant of the internal memory. It is characterized by being.

(Invention of Claim 35)
The vehicle power supply system according to any one of claims 1 to 34, further comprising an electric load (for example, resetting an internal memory such as an ECU) having dark current interrupting means capable of interrupting dark current and allowing dark current to be interrupted. It is characterized in that power is supplied from a secondary power source to an allowable electrical load).
Thereby, even when dark current is interrupted by the dark current interrupting means, power can be supplied from the sub power source.

(Invention of Claim 36)
The power supply system for a vehicle according to any one of claims 1 to 35, wherein a sub power switch is connected in series with the sub power.
In this case, for example, when the sub power source fails, the sub power source can be separated from the system by turning off the sub power switch, so that the safety of the system can be ensured.

(Invention of Claim 37)
The power supply system for a vehicle according to claim 36 is characterized in that the sub power switch is disposed between the generator and the sub power source on the generator side than the input side connection portion of the DC / DC converter.
In this case, the input voltage of the DC / DC converter can be limited to the voltage of the sub power supply, and the cost of the DC / DC converter can be reduced.

(Invention of Claim 38)
The vehicle power supply system according to any one of claims 1 to 37, wherein the DC / DC converter uses a series regulator.
The purpose of this is to eliminate the noise caused by switching of the power device by utilizing the small (or the same) voltage difference between the main power supply and the sub power supply. The complexity of the circuit can be prevented.

(Invention of Claim 39)
The power supply system for a vehicle according to any one of claims 1 to 38, wherein when the secondary power supply is detected to be fully charged during regenerative power generation such as when the vehicle is decelerated, the power supply voltage of the secondary power supply is fully charged by the generator. Regenerative power generation is performed at a lower voltage, and power supply to a general load is performed in the first control state or the second control state.

  If the sub-power supply is further charged after the sub-power supply is fully charged, there is a risk of battery deterioration due to overcharging. Therefore, when it is detected by the voltage or charge amount detection means that the secondary power supply is fully charged, the generator is controlled with a voltage (a voltage lower than the secondary power supply) that cannot be charged to the secondary power supply, and the first control is performed. Depending on the state or the second control state, power is supplied to the general load. Thereby, for example, on a road like a long downhill, even after the secondary power supply is fully charged by the regenerative power, the regenerative power can be effectively used by consuming the regenerative power with the general load. .

(Invention of Claim 40)
The power supply system for a vehicle according to any one of claims 3 to 38, wherein when the secondary power source is detected to be fully charged at the time of regenerative power generation such as when the vehicle is decelerated, the sub power source voltage in a fully charged state is generated by the generator. Regenerative power generation is performed at a lower voltage, and power is supplied to the general load in the first control state, the second control state, or the third control state.

  If the sub-power supply is further charged after the sub-power supply is fully charged, there is a risk of battery deterioration due to overcharging. Therefore, when it is detected by the voltage or charge amount detection means that the secondary power supply is fully charged, the generator is controlled with a voltage (a voltage lower than the secondary power supply) that cannot be charged to the secondary power supply, and the first control is performed. According to the state, the second control state, or the third control state, power is supplied to the general load. Thereby, for example, on a road like a long downhill, even after the secondary power supply is fully charged by the regenerative power, the regenerative power can be effectively used by consuming the regenerative power with the general load. .

(Invention of Claim 41)
The power supply system for vehicles according to any one of claims 1 to 40, wherein the main power supply is maintained in a fully charged state by the first control state.
By detecting the battery state of the main power source with the battery voltage or charging / discharging current, and supplying power from the sub power source or the generator to the general load using the DC / DC converter (first control state), The power supply can be kept fully charged.
Thereby, when the main power source is a battery such as lead, for example, a phenomenon in which the battery life is deteriorated by the accumulated discharge amount is known, but this can be suppressed and the life can be extended.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is an electric circuit diagram of a vehicle power supply system (hereinafter referred to as a power supply system S), and FIG. 2 is a flowchart showing a control procedure at the time of engine start.
The power supply system S includes a generator 1 that is driven by an engine (not shown) to generate electric power, and two power supplies (a main power supply 2 and a sub power supply 3), and an electric load (described later) mounted on the vehicle. Supply power.

The generator 1 is an alternator with an IC regulator and is belt-driven by an engine to generate a voltage of, for example, 13 to 14V. The generator 1 is directly connected to the sub power source 3 and is also connected to the main power source 2 through a power feeding circuit described below.
The power supply circuit includes, for example, a first power supply circuit 5 having a DC / DC converter 4 using a series regulator, and a second power supply circuit 7 having a switch 6. Are connected in parallel. In FIG. 1, the relay type switch 6 is shown in the second power supply circuit 7, but a semiconductor switch may be used instead of the relay type switch 6.

The main power source 2 is, for example, a general Pb (lead) battery, generates a voltage of 12 to 13 V (nominal voltage 12 V), and mainly supplies power to the general electric load 8 in preference to the sub power source 3. Do. The main power source 2 is connected to an important load (described later) related to basic driving and safety of the vehicle via a third power feeding circuit 9, and the third power feeding circuit 9 is connected to the sub power source 3. Diodes 10 and 11 are provided to prevent current flowing back from the side.

The sub power supply 3 is a high-performance battery (for example, Li-ion battery) that has better charge acceptability than the main power supply 2 and is easy to detect the state, and has an internal resistance smaller than that of the main power supply 2, for example, a voltage of 9 to 12 V (nominal Voltage 10.8V). For example, the sub power supply 3 collects the regenerative power generated by the generator 1 when the vehicle decelerates and stores the generated power of the generator 1. Further, the important load is connected to the generator 1 and the sub power supply 3 via a fourth power supply circuit 12, and the fourth power supply circuit 12 is prevented from flowing back from the main power supply 2 side. A diode 13 is provided.

  The general electric load 8 includes a starter 8a that starts the engine (cranking), and general loads 8b such as various lamps, wipers, audio devices, and air conditioners mounted on the vehicle. As described above, the general load 8b is supplied with power from the main power supply 2 in preference to the sub power supply 3. For example, when the power supply capability of the main power supply 2 is reduced, the sub load 3 or Electric power can be received from the generator 1.

  The important loads related to the basic driving and safety of the vehicle include a control device (referred to as a safety ECU 16) that electronically controls various actuators 14 related to the basic driving and safety of the vehicle via a relay 15, the main power supply. An electronic control device (referred to as system ECU 17) that electronically controls the system S (the generator 1, the DC / DC converter 4, the switch 6, etc.), and these important loads are either the main power source 2 or the sub power source 3 Even when one of them fails, power can be directly supplied from the other power source. That is, the redundancy of the power supply with respect to the important load is ensured.

The system ECU 17 can appropriately select a first control state, a second control state, and a third control state described below according to the operating states of the DC / DC converter 4 and the switch 6.
First control state: Power is supplied using the first power supply circuit 5, the DC / DC converter 4 is activated (ON), and the switch 6 is opened (OFF).
Second control state: Power is supplied using the second power supply circuit 7, the DC / DC converter 4 is stopped (OFF), and the switch 6 is closed (ON).
Third control state: Power is supplied using both the first power supply circuit 5 and the second power supply circuit 7, and the DC / DC converter 4 is activated (ON) and the switch 6 is closed. The third control state to be (ON) can be selected as appropriate.

Next, a control procedure when the engine is started by the system ECU 17 will be described based on a flowchart shown in FIG.
Step 10: An IG key (ignition key), which is an engine start switch, is input to the ST position (a position where the starter 8a is energized).
Step 11: The starter 8a is energized from the main power source 2.
Step 12: It is determined whether or not the generated voltage of the sub power supply 3 is a certain value or more. The generated voltage of the sub power supply 3 can be detected by, for example, the voltmeter 18 shown in FIG. When the determination result is YES, the process proceeds to the next Step 13, and when the determination result is NO, the process jumps to Step 15, and power supply from the sub power supply 3 to the starter 8a is stopped.

Step 13: The timing for supplying power from the sub power source 3 to the starter 8a is determined. Specifically, it is determined whether or not the voltage between the terminals of the main power supply 2 has recovered to a predetermined value, or whether or not a certain time has elapsed since the start of energization to the starter 8a.
As shown in FIG. 3, the voltage between the terminals of the main power supply 2 gradually drops after a large current flows through the starter 8a in the initial stage of energization, and then gradually recovers while the piston is slightly lowered when it passes over the top dead center. To go. Therefore, by monitoring the voltage between the terminals of the main power supply 2, it is possible to determine the timing for supplying power from the sub power supply 3 to the starter 8a.

Step 14 ... If the determination result in Step 13 is YES, the switch 6 provided in the second power supply circuit 7 is turned on to supply power from the sub power supply 3 to the starter 8a through the second power supply circuit 7 (this is the power Called Assist).
Step 15: Determines engine start. This start determination can also be made based on, for example, the engine speed or the voltage between terminals of the main power supply 2. When the determination result is NO, the process proceeds to Step 16, and when the determination result is YES, the process proceeds to Step 17.
Step 16 ... The engine is started again.
Step 17 ... The IG key is turned OFF to end this control.

  According to the first embodiment, after the start of energization of the starter 8a by the main power source 2, the power assist by the sub power source 3 is executed at a predetermined timing, whereby the output of the starter 8a is increased and the engine is started earlier. Is possible. In particular, in a vehicle equipped with an engine automatic stop / restart device (idle stop device), the start time can be shortened when restarting after the engine is automatically stopped, so that the start feeling of the occupant can be improved. .

  In addition, the power supply path to the safety ECU 16 that is an important load is a path connected from the main power source 2 to the safety ECU 16 via the third power feeding circuit 9 and from the sub power source 3 via the fourth power feeding circuit 12. Since there are two paths connected to the safety ECU 16, even if one of the power supply and the path fails, the other power supply and path can supply redundantly. In addition, since the third power supply circuit 9 and the fourth power supply circuit 12 are provided with diodes 10 and 13 for preventing reverse current flow, respectively, the third power supply circuit 9 and the fourth power supply circuit are provided. No two power sources (main power source 2 and sub power source 3) are connected to each other.

  In the first embodiment, as an example of regenerative power generation, a case where power generation is performed using kinetic energy at the time of vehicle deceleration is described, but in addition to this, for example, heat energy such as engine exhaust heat or cooling heat is used. It can also be applied to power generation or a power generation mode using exhaust gas airflow energy. These power generation modes include those that directly generate power from thermal energy using a thermoelectric element, or those that once convert thermal energy into kinetic energy to generate power.

  Furthermore, in the power supply system S described in the first embodiment, an example in which the main power supply 2 has a higher generated voltage (nominal voltage) than the sub power supply 3 is described. It can also be applied when the generated voltage (nominal voltage) is higher. As an example, the main power source 2 generates a voltage of 12 to 13 V (nominal voltage 12 V) as in the first embodiment, and the sub power source 3 generates a voltage of 12 to 16.4 V (nominal voltage 14.4 V). To do. Moreover, since the generated voltage of the sub-power supply 3 is increased, the power generation capability of the generator 1 is increased accordingly, and a voltage of 13 to 17 V is generated.

  Next, power supply control from the generator 1 or the sub power source 3 to the main power source 2 will be described based on the flowchart shown in FIG. This is a method of detecting and controlling the charge amount of the sub power supply 3. Step 20: Whether or not the output capability of the DC / DC converter 4 is larger than the power consumption (referred to as the full load value) of all the electric loads, and whether the charging capacity per fixed time of the sub power supply 3 is larger than the full load value. judge. When the determination result is YES, the process proceeds to Step 21, and when the determination result is NO, the process proceeds to Step 22.

Step 21: Since there is a margin in the charging capacity of the sub power source 3 with respect to the full load value and there is also a margin in the output capability of the DC / DC converter 4, the power generation by the generator 1 is cut and the sub power source 3 Power is supplied to the main power supply 2 through the first power supply circuit 5 having the DC converter 4 (first control state).
Step 22: Whether the output capability of the DC / DC converter 4 is equal to or lower than the full load value, and the capacity per unit time of the sub power supply 3 is larger than the full load value, or whether the temperature of the DC / DC converter 4 is higher than the constant value. Determine whether. When the determination result is YES, the process proceeds to Step 23, and when the determination result is NO, the process proceeds to Step 24.

Step 23 ... Although there is a margin in the charging capacity of the sub power supply 3 with respect to the full load value, there is no margin in the output capability of the DC / DC converter 4 (or the temperature of the DC / DC converter 4 is high). The power generation by the power supply is cut, and power is supplied from the sub power supply 3 to the main power supply 2 through the first power supply circuit 5 and the second power supply circuit 7 (described as a switch circuit in the drawing) (third control state).
Step 24: It is determined whether or not the output capability of the DC / DC converter 4 is less than or equal to the full load value, and the capacity per fixed time of the sub power supply 3 is less than or equal to the full load value. When the determination result is YES, the process proceeds to Step 25, and when the determination result is NO, the process proceeds to Step 26.

Step 25: There is no margin in the charging capacity of the sub power supply 3 with respect to the full load value, and there is no margin in the output capability of the DC / DC converter 4 (however, the temperature of the DC / DC converter 4 is not more than a certain value). Therefore, the generator 1 generates power (Lo level), and power is supplied from the generator 1 to the main power supply 2 through the first power supply circuit 5 and the second power supply circuit 7 (third control state).
Step 26: It is determined whether or not the temperature of the DC / DC converter 4 is higher than a certain value, or whether the sub power source capacity is higher than a certain value. When the determination result is YES, the process proceeds to Step 27, and when the determination result is NO, the process proceeds to Step 28.

Step 27: In order to prevent a heat generation failure of the DC / DC converter 4 and to prevent overcharging of the sub power source 3, power is supplied from the generator 1 to the main power source 2 using only the second power feeding circuit 7 ( Second control state). At this time, the power generation level (Lo) of the generator 1 is set such that power can be supplied according to the general load 8b even when the sub power supply 3 is fully charged.
Step 28: It is determined whether or not the charging capacity of the sub power source 3 is within a predetermined range (for example, between 40% and 50%). When the determination result is YES, the process proceeds to Step 29, and when the determination result is NO, the process proceeds to Step 30.

Step 29: Since the charging capacity of the sub power supply 3 is reduced, the power generation capacity of the generator 1 is increased (Hi level). When a high load with large power consumption is turned on, the idle speed is increased by a predetermined speed (first idle up).
Step 30: It is determined whether or not the charging capacity of the sub power source 3 is within a predetermined range (for example, between 30% and 40%). When the determination result is YES, the process proceeds to Step 31, and when the determination result is NO, the process proceeds to Step 32.

Step 31 ... Although the power generation capacity of the generator 1 is increased, the charging capacity of the sub power source 3 does not increase, so the first idle up is performed and the power supply to the general load 8b is cut (or suppressed). ) When a high load with large power consumption is turned on among the general loads 8b, the idle speed is further increased by a predetermined speed (second idle up).
Step 32 ... An alarm (failure) of the sub power supply 3 is given to the driver (for example, urging to a safe place, guiding a route to a dealer with a navigation device, etc.).

According to the second embodiment, when the output capability of the DC / DC converter 4 is less than or equal to the full load value, the switch 6 is turned on and the second power feeding circuit 7 is used to feed the DC / DC converter 4. Power supply from the generator 1 or the sub power supply 3 to the main power supply 2 is possible even when the power supply is insufficient or a failure occurs.
Further, when the temperature of the DC / DC converter 4 becomes higher than a certain value, the power supply capability of the DC / DC converter 4 is suppressed, or the switch 6 is turned on and only the second power supply circuit 7 is used. Thus, the heat generation failure of the DC / DC converter 4 can be prevented. Thus, by providing the second power supply circuit 7 having the switch 6 in parallel with the first power supply circuit 5 having the DC / DC converter 4 between the sub power supply 3 and the main power supply 2, the DC The capacity and size of the DC / DC converter 4 can be reduced.

Further, as described in Step 27, the power generation level (Lo) of the generator 1 is set so that the power supply according to the general load 8b can be supplied even when the sub power supply 3 is fully charged. Regeneration can be realized not by charging but by supplying power to the general load 8b. For example, the regenerative power can be effectively used by consuming the regenerative power with the general load 8b even after the regenerative power is sufficiently accumulated in the sub power source 3 on a long downhill (fully charged state).
In the second embodiment, the control content is established regardless of the magnitude of the generated voltage (nominal voltage) of the main power source 2 and the sub power source 3. That is, even when the generated voltage (nominal voltage) is higher in the main power supply 2 than in the sub power supply 3, the sub power supply 3 is established even in the case where the generated voltage (nominal voltage) is higher than that of the main power supply 2.

Next, the control of the generator 1 will be described based on the flowchart shown in FIG. This is a method of controlling only by the power supply voltage without using the SOC detection means.
Step 40: It is determined whether or not the output voltage V1 of the sub power source 3 is equal to or higher than a certain value (for example, 12V). When the determination result is YES, the process proceeds to Step 41, and when the determination result is NO, the process proceeds to Step 42.
Step 41: Since there is a margin in the charging capacity of the sub power source 3, the power generation of the generator 1 is cut off, and power is supplied from the sub power source 3 to the main power source 2 through the first power feeding circuit 5 (DC / DC converter 4) (first). 1 control state).

Step 42: It is determined whether or not the vehicle is decelerating and the output voltage V1 of the sub power source 3 is smaller than a certain value (for example, 12V). When the determination result is YES, the process proceeds to Step 43, and when the determination result is NO, the process proceeds to Step 44.
Step 43 ... The regenerative power generated by the generator 1 is recovered to the sub power source 3 and also supplied to the main power source 2 through the first power supply circuit 5 (first control state).
Step 44: It is determined whether the vehicle is decelerating and the output voltage V1 of the sub power source 3 is greater than a certain value (for example, 12V). When the determination result is YES, the process proceeds to Step 45, and when the determination result is NO, the process proceeds to Step 46.

  Step 45: Since the output voltage V1 of the sub power supply 3 is greater than a certain value even when the vehicle is decelerating, the regenerative power (Lo level) generated by the generator 1 is used as the first power supply circuit 5 and the second power supply circuit. Power is supplied to the main power supply 2 through 7 (denoted as a switch circuit in the figure) (third control state). Alternatively, power is supplied to the main power supply 2 through one of the first power supply circuit 5 and the second power supply circuit 7. Thereby, even when the sub power supply 3 is in a fully charged state, power supply according to the general load 8b is performed. Therefore, regeneration during deceleration can be realized by supplying power to the general load 8b instead of charging. Step 46: It is determined whether the vehicle is in steady running or acceleration and the output voltage V2 of the DC / DC converter 4 is within a predetermined range (for example, between 12.5V and 13V). When the determination result is YES, the process proceeds to Step 47, and when the determination result is NO, the process proceeds to Step 48.

Step 47: The power supply capability of the DC / DC converter 4 is increased, and power is supplied from the generator 1 to the main power supply 2 through the first power supply circuit 5 (first control state). This corresponds to a case where the charge amount of the main power supply 2 is reduced and the output instruction of the DC / DC converter 4 is insufficient. Therefore, the output of the DC / DC converter 4 is increased and the charge amount of the main power supply 2 is kept high. This is performed to prevent the main power supply 2 from deteriorating due to discharge.
Step 48: It is determined whether or not the temperature of the DC / DC converter 4 is higher than a certain value, or whether or not the output voltage V1 of the sub power supply 3 is within a predetermined range (for example, between 11V and 12V). When the determination result is YES, the process proceeds to Step 49, and when the determination result is NO, the process proceeds to Step 50.

Step 49: The generator 1 always generates power (Lo level) and supplies power to the main power source 2 from the generator 1 through the second power supply circuit 7 (second control state). This is to suppress the temperature rise of the DC / DC converter 4.
Step 50: Whether or not the output voltage V1 of the sub power supply 3 is smaller than a certain value (for example, 11V) and the output voltage V2 of the DC / DC converter 4 is within a predetermined range (for example, between 12V to 12.5V). judge. When the determination result is YES, the process proceeds to Step 51, and when the determination result is NO, the process proceeds to Step 52.

Step 51 ... Although the generator 1 is generating power (Lo level), the charging capacity of the sub power supply 3 is low and the output voltage V2 of the DC / DC converter 4 is also low, so that the first idling speed is increased. And the power supply to the general load 8b is cut (or suppressed). Further, when a high load with large power consumption is turned on among the general loads 8b, a second idle up is performed to further increase the idle speed. Since this is a situation where the amount of power generation is low and the power supply of the DC / DC converter 4 cannot catch up, it corresponds to idle-up.
Step 52... Alerts the driver of an abnormality of the power supply system S (same as Step 32).

According to the third embodiment, the output of the generator 1 can be efficiently controlled according to the output voltage V1 of the sub power supply 3 and the output voltage V2 of the DC / DC converter 4.
Further, since the generator 1 is connected to the sub power source 3 having high performance (excellent charge acceptance than the main power source 2 and high accuracy and easy detection), the generator 1 generates power when the vehicle decelerates. The regenerative power can be efficiently collected in the sub power source 3. In other words, it is important that the difference between the voltage of the generator 1 and the power supply voltage is large in order to recover a large amount of regenerative energy in a short period of time during deceleration.

  However, when the difference between the voltage of the generator 1 and the power supply voltage is small and the internal resistance of the power supply voltage is large, for example, in the main power supply 2 having poor charge acceptance compared to the sub power supply 3, FIG. As shown in FIG. 4, the battery is not charged up to the allowable SOC within the predetermined deceleration time A, and sufficient supplementary charging cannot be performed. Moreover, if the difference between the generated voltage of the generator 1 and the power supply voltage is too large, an overshoot exceeding the allowable SOC occurs as shown in FIG. 6C. For example, the sub power supply 3 (Li ion battery) In such a high-performance battery, the heat generation amount increases, and the performance may deteriorate due to an increase in internal resistance.

  On the other hand, in this power supply system S, since the generated voltage of the sub power supply 3 for recovering the regenerative power at the time of vehicle deceleration is smaller than that of the main power supply 2 and the internal resistance is also small, the charge acceptability of the sub power supply 3 is good. As shown in FIG. 6 (a), it is possible to recover a large amount of regenerative energy within a predetermined deceleration time A. As a result, the maximum regenerative charge from the generator 1 to the sub power supply 3 can be performed with a short deceleration, and the load on the engine is reduced by cutting off the power generation in the generator 1 during steady running or acceleration. Will be reduced and fuel efficiency will be improved.

  In the third embodiment, an example in which the generated voltage (nominal voltage) of the sub power source 3 is lower than that of the main power source 2 is described. However, the generated voltage (nominal voltage) of the sub power source 3 is lower than that of the main power source 2. The same control content can be applied when the value is high. However, since the generated voltage of the sub power supply 3 is increased, the voltage determination value of each step (S40, S42, S44, S48, S50 in FIG. 5) for determining the output voltage V1 of the sub power supply 3 is changed accordingly. There is a need. For example, voltage determination values when the generated voltage (nominal voltage) of the sub power supply 3 is 14.4 V are shown in the flowchart (S40a, S42a, S44a, S48a, S50a) in FIG.

Next, control when the generated voltage is higher in the sub power supply 3 than in the main power supply 2 will be described based on the flowchart shown in FIG.
Step 60 ... It is determined whether or not the generated voltage is higher in the sub power source 3 than in the main power source 2. When the determination result is NO (sub power supply voltage ≦ main power supply voltage), the process proceeds to the next Step 61, and when the determination result is YES, the process proceeds to Step 62.
Step 61: Electric power is generated by the generator 1, and the sub power supply 3 is charged. This process is continued until the generated voltage of the sub power supply 3 becomes higher than the generated voltage of the main power supply 2.

Step 62: It is determined whether or not the power supply amount from the sub power source 3 to the main power source 2 and the general load 8b is larger than a predetermined value. When the determination result is NO, the process proceeds to the next Step 63, and when the determination result is YES, the process proceeds to Step 64.
Step 63 ... selects the first control state. That is, the DC / DC converter 4 is activated (ON) and the switch 6 is opened (OFF), and the necessary power from the sub power source 3 to the main power source 2 and the general load 8b via the first power supply circuit 5 Supply. In this control, for example, the voltage on the outlet side of the DC / DC converter 4 is controlled as a constant value. Then, it progresses to Step65.

Step 64... Power is supplied at the maximum output of the DC / DC converter 4 in order to supply a large amount of power (the shortage is handled by discharging the main power supply 2).
Step 65: It is determined whether or not the generated voltage of the sub power supply 3 has decreased to the allowable rated voltage or less of the general load 8b. When the determination result is YES, the process proceeds to Step 66, and when the determination result is NO, the process returns to Step 62.
Step 66 ... selects the second control state. That is, the DC / DC converter 4 is stopped (OFF) and the switch 6 is closed (ON), and the power is supplied from the sub power source 3 to the main power source 2 and the general load 8b via the second power feeding circuit 7. To do.

  According to the control of the fourth embodiment, an overvoltage is not applied to the general load 8b such as various lights, and the life reduction of the general load 8b can be suppressed. In addition, when the generated voltage of the sub power supply 3 is lowered to the allowable rated voltage of the general load 8b or less, switching from the DC / DC converter 4 to the switch 6 causes no loss at the time of step-down by the DC / DC converter 4. Efficient power supply becomes possible.

Next, control when switching from the first control state to the second control state or when switching from the second control state to the first control state will be described based on the flowchart shown in FIG.
Step 70: An instruction to switch the control state is issued. Specifically, it is an instruction to switch from the first control state to the second control state, or an instruction to switch from the second control state to the first control state.
Step 71: It is determined whether or not the voltage difference between the main power source 2 and the sub power source 3 is larger than a predetermined value. When the determination result is YES, the process proceeds to the next Step 72, and when the determination result is NO, the process jumps to Step 73.

Step 72 ... The output voltage of the DC / DC converter 4 is stepped up to the higher voltage of the main power supply 2 and the sub power supply 3 or down to the lower voltage, and then the process returns to Step 71. Step 73 ... The second control state is selected when the voltage difference between the main power source 2 and the sub power source 3 becomes smaller than a predetermined value (when the determination result in Step 71 is NO).
According to the control of the fifth embodiment, voltage fluctuations when the control state is switched (for example, when the switch 6 provided in the second power feeding circuit 7 is turned on) can be suppressed, so that blinking of lights and the like can be prevented. .

Subsequently, FIG. 10 illustrates a control example when switching to the third control state (that is, supplying power using both the DC / DC converter 4 and the switch 6) when the second control state is selected. This will be described based on the flowchart shown.
Step 80 ... The second control state is selected. That is, the switch 6 is closed (ON) and power is supplied through the second power supply circuit 7.

Step 81 ... It is determined whether or not the temperature of the switch 6 exceeds a predetermined value. When the determination result is YES, the process proceeds to the next step 82, and when the determination result is NO, the process returns to step 80.
Step 82 ... Starts (ON) the DC / DC converter 4 to switch to the third control state. That is, power is supplied by using the first power supply circuit 5 and the second power supply circuit 7 in combination.
According to the control of the sixth embodiment, when the temperature of the switch 6 exceeds a predetermined value, the second power feeding circuit 7 having the switch 6 and the first power feeding circuit 5 having the DC / DC converter 4 are used in combination. Since power is supplied, heat generation of the switch 6 can be suppressed.

FIG. 11 is an electric circuit diagram of the power supply system S according to the seventh embodiment.
In the power supply system S according to the seventh embodiment, as shown in FIG. 11, a sub power switch 19 (for example, a relay switch) is connected to the negative side of the sub power supply 3, and energization control of the sub power switch 19 is performed by the system ECU 17. This is an example.
In this configuration, for example, when the sub power supply 3 breaks down, the sub power supply switch 19 is turned off when the sub power supply switch 19 is turned off when retreating to a safe place or when traveling to a dealer. Since it can isolate | separate, the safety | security of the power supply system S is securable.

Further, when an electric load having a large power consumption is used among the general loads 8b, power is supplied from the generator 1 via the first power supply circuit 5 or the second power supply circuit 7 or both the circuits 5 and 7. However, it is possible to reliably supply power to the main power supply 2 and the general load 8b by turning off the sub power switch 19.
Furthermore, in vehicles equipped with an idle stop device that automatically stops the engine when it is temporarily stopped due to a red light at the intersection, etc., the sub power switch 19 is turned off in preparation for the next start (when restarting after automatic stop). By doing so, a certain electric capacity can be ensured at the time of restart.

Furthermore, in the case of quick charging at the time of deceleration with the 100% capacity voltage of the sub power supply 3 being smaller than the output voltage of the generator 1, by turning off the sub power switch 19, in a fatal mode such as power generation control failure, Overcharge to the sub power supply 3 can be cut.
The sub power switch 19 may be connected to the positive side of the sub power source 3 as shown in FIG. However, FIG. 13 is an example in which a sub power switch 19 is arranged between the generator 1 and the sub power source 3 on the generator 1 side of the input side connection portion B of the DC / DC converter 4.

FIG. 14 is an electric circuit diagram of the power supply system S according to the eighth embodiment.
The power supply system S according to the eighth embodiment is an example in which a capacitor 20 is connected to the output side (main power supply 2 side) of the DC / DC converter 4 of the first power feeding circuit 5 as shown in FIG.
Thereby, a stable voltage can be supplied to the main power supply 2 through the DC / DC converter 4.

FIG. 15 is an electric circuit diagram of the power supply system S according to the ninth embodiment.
The power supply system S according to the ninth embodiment is an example of detecting the charge acceptability of the main power supply 2 by monitoring the output voltage of the main power supply 2 with a voltmeter 21 or the like, as shown in FIG.
In this example, since it is not necessary to detect the charge acceptability of the main power supply 2 with sensors (for example, a sensor that detects current, voltage, temperature, etc.), a low-cost system can be realized.

FIG. 16 is an electric circuit diagram of the power supply system S according to the tenth embodiment.
In the power supply system S according to the tenth embodiment, as shown in FIG. 16, an electrical load 22 (for example, a defogger, a seat heater, etc.) that allows voltage fluctuation and does not require dark current is used instead of the main power supply 2. For example, it is an example of being connected to the sub power supply 3 and the generator 1 via the relay 23. A controller 24 (ECU) that controls opening and closing of the relay 23 is connected to the main power supply 2 and is supplied with power from the main power supply 2.

In this example, the battery of the main power supply 2 that has occurred during long-term parking, half-doors, etc., is cut only to the reset allowable load, and the power is cut (cuts the dark current). The electrical load 22 that can be prevented and does not require dark current can be dealt with by supplying power from the sub power source 3 or the generator 1. In addition, the following can be considered as means for cutting dark current (dark current interrupting means of the present invention).
a) A timer function that cuts dark current after a certain period of time,
b) detecting the capacity of the sub power supply 3;
c) receiving an external communication signal,
d) Detecting the absence of transmission or reception of radio wave transmitters,
e) A switch such as a touch panel on the exterior of the vehicle can be used.

FIG. 17 is an electric circuit diagram of the power supply system S according to the eleventh embodiment.
The power supply system S according to the eleventh embodiment is provided with a bypass circuit 25 that bypasses the sub power switch 19 and is connected to the third power supply circuit 9 with respect to the circuit diagram shown in FIG. It is an example.
As a result, even when the sub power switch 19 is OFF, power can be supplied from the main power source 2 or the sub power source 3 to the safety ECU 16, so that a redundant system for the safety ECU 16 involved in traveling safety can be secured.

FIG. 18 is an electric circuit diagram of the power supply system S according to the twelfth embodiment.
The power supply system S according to the twelfth embodiment is an example in which the voltage stabilizer 26 is arranged in the third power feeding circuit 9 with respect to the circuit diagram (see FIG. 15) described in the ninth embodiment, for example. Thereby, the minimum guaranteed voltage can be reliably supplied to the system ECU 17 which is an important load.

(Modification)
Two power sources (main power source 2 and sub power source 3) used in the power source system S of the present invention are described in the first embodiment when the main power source 2 has a higher nominal voltage or nominal capacity than the sub power source 3. However, conversely, the sub power supply 3 may have a higher nominal voltage (or nominal capacity) than the main power supply 2. Moreover, you may have the area | region where the working voltage of the main power supply 2 and the sub power supply 3 becomes the same.

  In the first embodiment, the Pb battery and the Li-ion battery are described as examples of the main power supply 2 and the sub power supply 3, respectively, but are not limited thereto. As the main power source 2, in addition to the Pb battery, a Li ion battery, a Ni hydrogen battery or the like can be used. As the sub power source 3, in addition to the Li ion battery, a Pb battery, a Ni hydrogen battery, an electric double layer capacitor, or the like Can be used.

  In the first embodiment, the alternator is described as the generator 1. However, a motor generator having a power generation function may be employed instead of the alternator. Furthermore, the generator 1 may be connected to an axle, a crankshaft, or the like by transmission means such as a gear or a belt, instead of being driven by a belt by an engine. Alternatively, it may be directly connected to an axle or a crankshaft. Further, a heat regeneration generator capable of generating electric power by converting thermal energy into kinetic energy, a thermoelectric element capable of directly converting thermal energy into electric energy, or the like may be used.

1 is an electric circuit diagram of a vehicle power supply system according to Embodiment 1. FIG. 3 is a flowchart illustrating a control procedure when starting the engine according to the first embodiment. It is a voltage waveform diagram of the main power supply at the time of engine start concerning Example 1. 7 is a control flowchart of a power supply system according to a second embodiment. 10 is a control flowchart of a power supply system according to a third embodiment. It is explanatory drawing regarding the regenerative charge at the time of the deceleration which concerns on Example 3. FIG. 10 is a control flowchart of a power supply system according to a third embodiment. 10 is a control flowchart of a power supply system according to a fourth embodiment. 10 is a control flowchart of a power supply system according to a fifth embodiment. 10 is a control flowchart of a power supply system according to Embodiment 6. FIG. 10 is an electric circuit diagram of a power supply system according to a seventh embodiment. FIG. 10 is an electric circuit diagram of a power supply system according to a seventh embodiment. FIG. 10 is an electric circuit diagram of a power supply system according to a seventh embodiment. FIG. 10 is an electric circuit diagram of a power supply system according to an eighth embodiment. FIG. 10 is an electric circuit diagram of a power supply system according to Embodiment 9. FIG. 10 is an electric circuit diagram of a power supply system according to Example 10. FIG. 12 is an electric circuit diagram of a power supply system according to an eleventh embodiment. FIG. 14 is an electric circuit diagram of a power supply system according to Embodiment 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Generator 2 Main power supply 3 Sub power supply 4 DC / DC converter 5 1st electric power feeding circuit 6 Switch 7 2nd electric power feeding circuit 8 General electric load 8a Starter (general electric load)
8b General load (general electric load)
DESCRIPTION OF SYMBOLS 9 3rd electric power feeding circuit 10 Diode provided in 3rd electric power feeding circuit 11 Diode provided in 3rd electric power feeding circuit 12 4th electric power feeding circuit 13 Diode provided in 4th electric power feeding circuit 16 Safety ECU (important load)
17 System ECU (control means / important load)
19 Sub power switch 22 Electric load that does not require dark current S Vehicle power system

Claims (41)

A generator mounted on the vehicle;
A main power supply to which general loads such as lamps and audio devices are connected;
A secondary power source connected to the generator, recovering regenerative power generated by the generator using kinetic energy such as deceleration, or heat energy such as exhaust heat, and storing the generated power of the generator; ,
A first power supply circuit that connects the sub power source, the main power source, and the general load via a DC / DC converter;
In parallel with the first power supply circuit, a second power supply circuit that connects the sub power supply, the main power supply, and the general load via a switch;
Control means for controlling the operation of the DC / DC converter and the switch,
This control means
A vehicle power supply system capable of selecting a first control state in which the DC / DC converter is started and the switch is opened, or a second control state in which the DC / DC converter is stopped and the switch is closed. . A generator driven by the engine to generate electricity;
A main power supply to which general loads such as lamps and audio devices are connected;
A secondary power source connected to the generator, for collecting regenerative power generated by the generator when the vehicle decelerates, and for storing the generated power of the generator generated by driving the engine;
A first power supply circuit that connects the sub power source, the main power source, and the general load via a DC / DC converter;
In parallel with the first power supply circuit, a second power supply circuit that connects the sub power supply, the main power supply, and the general load via a switch;
Control means for controlling the operation of the DC / DC converter and the switch,
This control means
A vehicle power supply system capable of selecting a first control state in which the DC / DC converter is started and the switch is opened, or a second control state in which the DC / DC converter is stopped and the switch is closed. . In the vehicle power supply system according to claim 1 or 2,
The power supply system for a vehicle, wherein the control means can select a third control state that activates the DC / DC converter and closes the switch. The vehicle power supply system according to any one of claims 1 to 3,
The power supply system for vehicles, wherein the main power supply has a larger nominal voltage or nominal capacity than the sub-power supply. The vehicle power supply system according to any one of claims 1 to 3,
The vehicle power supply system, wherein the main power supply has a smaller nominal voltage or nominal capacity than the sub-power supply. In the vehicle power supply system according to any one of claims 1 to 5,
The vehicular power supply system, wherein the main power supply and the sub power supply have a region in which operating voltages are substantially the same. In the vehicle power supply system according to any one of claims 1 to 6,
The power supply system for vehicles, wherein the main power supply is superior in discharge characteristics at a low temperature than the sub power supply. In the vehicle power supply system according to any one of claims 1 to 7,
The sub-power source is more excellent in charge acceptability than the main power source, and can easily detect a state. In the vehicle power supply system according to any one of claims 1 to 8,
The main power source is a lead battery, a Li ion battery, or a Ni hydrogen battery, and the sub power source is a lead battery, a Li ion battery, a Ni hydrogen battery, or an electric double layer capacitor. Power supply system for vehicles. In the vehicle power supply system according to any one of claims 1 to 3 and 5 to 9,
The control means, when supplying power from the sub-power source to the main power source and the general load, if the voltage of the sub-power source has dropped to an allowable rated voltage of the general load or less, A power supply system for a vehicle, wherein a control state is selected. In the vehicle power supply system according to any one of claims 1 to 10,
When the amount of power supplied from the sub power source to the main power source and the general load or the amount of power supplied from the main power source to the sub power source and the general load is referred to as a power supply amount,
The power supply system for vehicles, wherein the control means selects one of the first control state and the second control state in accordance with the power supply amount. In the vehicle power supply system according to claim 11,
The control means selects the first control state when the power supply amount is equal to or less than a predetermined value, and selects the second control state when the power supply amount is larger than the predetermined value. Power supply system for vehicles. In the vehicle power supply system according to any one of claims 1 to 9,
The vehicle power supply system, wherein the control means selects one of the first control state and the second control state in accordance with a voltage difference between the main power supply and the sub power supply. In the vehicle power supply system according to claim 13,
The control means selects the second control state when the voltage difference between the main power source and the sub power source is equal to or less than a predetermined value, and when the voltage difference between the main power source and the sub power source is larger than the predetermined value. The vehicle power supply system, wherein the first control state is selected. In the vehicle power supply system according to any one of claims 1 to 9,
When the amount of power supplied from the sub power source to the main power source and the general load or the amount of power supplied from the main power source to the sub power source and the general load is referred to as a power supply amount,
The control means selects one of the first control state and the second control state according to a voltage difference between the main power source and the sub power source and the power supply amount. Power supply system for vehicles. In the vehicle power supply system according to claim 15,
When the voltage of the sub power source is higher than the voltage of the main power source and the amount of power supplied from the sub power source to the main power source and the general load is larger than a predetermined value, the control means first The vehicle power supply system is switched from the first control state to the second control state after the control state is selected and the voltage of the sub-power supply drops below the allowable rated voltage of the general load. . In the vehicle power supply system according to any one of claims 1 to 16,
A third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from the sub power source, and a fourth power feeding circuit that feeds the important load from the main power source,
The third power supply circuit and the fourth power supply circuit are each provided with a diode for preventing a backflow of an energized current. In the vehicle power supply system according to any one of claims 1 to 4 or 6 to 16,
A third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from the sub power source, and a fourth power feeding circuit that feeds the important load from the main power source,
A power supply system for vehicles, wherein a diode for preventing a backflow of an energized current is provided in the third power supply circuit when the main power supply has a larger nominal voltage or nominal capacity than the sub-power supply. In the vehicle power supply system according to any one of claims 1 to 3 or 5 to 16,
A third power feeding circuit that feeds an important load related to basic driving and safety of the vehicle from the sub power source, and a fourth power feeding circuit that feeds the important load from the main power source,
When the main power supply has a nominal voltage or nominal capacity smaller than that of the sub-power supply, the fourth power supply circuit is provided with a diode for preventing a backflow of an energization current. In the vehicle power supply system according to any one of claims 17 to 19,
The control means opens the switch when one of the main power supply and the sub power supply fails when the second control state is selected. In the vehicle power supply system according to claim 20,
The vehicular power supply system, wherein the control means opens the switch when a short circuit occurs between a positive electrode and a negative electrode of the main power supply or the sub power supply. In the vehicle power supply system according to claim 20,
The vehicle power supply system, wherein the control means opens the switch when the performance of the main power supply deteriorates. In the vehicle power supply system according to claim 20,
The vehicle power supply system, wherein the control means opens the switch when the performance of the sub power supply is deteriorated. In the vehicle power supply system according to claim 20,
The control means stops the DC / DC converter when one of the main power supply and the sub power supply fails when the first control state is selected. Power system. In the vehicle power supply system according to any one of claims 3 to 24,
The control means switches from the second control state to the third control state when the temperature of the switch exceeds a predetermined value when the second control state is selected. Vehicle power supply system. In the vehicle power supply system according to any one of claims 1 to 25,
The vehicle power supply system, wherein the general load connected to the main power supply includes an electric load that requires a dark current after the engine is stopped. In the vehicle power supply system according to any one of claims 1 to 26,
When the control means switches from the first control state to the second control state, or when switching from the second control state to the first control state, the control means outputs the output voltage of the DC / DC converter. The vehicle power supply system is characterized in that the control state is switched after the voltage of the main power supply and the sub power supply is boosted to a higher voltage or lowered to a lower voltage. The vehicle power supply system according to any one of claims 1 to 27,
The control means detects a use state such as a temperature or a voltage of the DC / DC converter when the first control state is selected, and if the detected use state exceeds a specified value, A vehicle power supply system that switches from the first control state to the second control state. The vehicle power supply system according to any one of claims 1 to 28,
The control means controls the output voltage of the DC / DC converter substantially the same as the output voltage of the generator when the first control state is selected. The vehicle power supply system according to any one of claims 1 to 28,
The control means controls the output voltage of the generator substantially the same as the output voltage of the DC / DC converter when the first control state is selected. In the vehicle power supply system according to any one of claims 1 to 30,
The vehicle power system according to claim 1, wherein the control means detects charge acceptability of the main power source based on an output state of the DC / DC converter when the first control state is selected. The vehicle power supply system according to any one of claims 1 to 31,
The control means detects the voltage of the sub power supply and the output voltage of the DC / DC converter according to the running state of the vehicle, and controls the output of the generator based on the detection result. Power system. The vehicle power supply system according to any one of claims 1 to 32,
A power supply system for a vehicle, wherein an electric load that does not require dark current is fed from the sub power supply. The vehicle power supply system according to claim 33,
The electric load that does not require dark current is an electric load such as an ECU that does not have an internal memory, or an electric load such as an ECU that always uses an initial constant of the internal memory. . The vehicle power supply system according to any one of claims 1 to 34,
A vehicle power supply system comprising dark current interrupting means capable of interrupting dark current and supplying power from the sub power source to an electric load that permits dark current interrupt. In the vehicle power supply system according to any one of claims 1 to 35,
A vehicle power supply system comprising a sub power switch connected in series with the sub power source. The vehicle power supply system according to claim 36,
The vehicular power supply system, wherein the sub power switch is disposed between the generator and the sub power source on the generator side of the input side connection portion of the DC / DC converter. In the vehicle power supply system according to any one of claims 1 to 37,
The DC / DC converter uses a series regulator, and is a vehicle power supply system. In the vehicle power supply system according to any one of claims 1 to 38,
When it is detected that the sub power supply is fully charged during regenerative power generation, the power generator performs regenerative power generation at a voltage lower than the sub power supply voltage in the fully charged state, and the first control state or second A power supply system for a vehicle that implements power supply to the general load according to the control state. The vehicle power supply system according to any one of claims 3 to 38,
When it is detected that the sub power supply is fully charged during regenerative power generation, the power generator performs regenerative power generation at a voltage lower than the sub power supply voltage in the fully charged state, and the first control state or second A power supply system for a vehicle, wherein power is supplied to the general load according to the control state or the third control state. In the vehicle power supply system according to any one of claims 1 to 40,
The vehicle power supply system, wherein the main power supply is maintained in a fully charged state in accordance with the first control state.

Images