JP4832116B2 - Vehicle power supply system - Google Patents

Description

  The present invention relates to a vehicle power supply system, and more particularly to a vehicle power supply system that supplies electric power to an on-vehicle electric load by a plurality of power generation means.

2. Description of the Related Art Conventionally, a vehicular power generation device provided with a plurality of generators driven by an engine is known (see, for example, Patent Document 1). This vehicular power generation device makes it possible to obtain appropriate power generation characteristics according to the operating state of the engine by making the output characteristics of a plurality of generators different from each other and driving each generator with a different pulley ratio. The power for the entire vehicle.
Japanese Patent Laid-Open No. 5-95637

  However, in the above-described prior art, since the generator drive source is an engine, an electric load that does not require electric power when the vehicle is stopped if the engine is rotating even when the vehicle is stopped, such as in an idle rotation state. Also, power can be supplied from the generator. That is, there is a possibility that the power generation efficiency may be reduced by generating the electric load for the electric load that originally does not require power when the vehicle is stopped.

  Accordingly, an object of the present invention is to provide a vehicle power supply system that can improve the efficiency of power generation.

In order to solve the above problems, as a first invention,
Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
The second power generation means provides a vehicular power supply system that supplies generated electric power to an electric load that requires electric power only when traveling, out of the in-vehicle electric loads.

As a second invention,
Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
The first power generation means does not supply the generated electric power to an electric load that requires electric power only during traveling among the in-vehicle electric loads, and the second power generation means A power supply system for a vehicle is provided that supplies generated electric power to an electric load that requires electric power only when traveling.

  A third invention is a vehicle power supply system according to the first or second invention, wherein the electric power is supplied by the first power generation means and the power is supplied by the second power generation means. The electrical loads to be used are different from each other.

  According to a fourth aspect of the present invention, there is provided a vehicle power supply system according to the first or second aspect of the present invention, comprising a voltage conversion unit, wherein the voltage conversion unit includes the output voltage of the first power generation unit and the second power generation unit. The voltage conversion between the output voltages of the power generation means is performed.

  The fifth invention is a power supply system for a vehicle according to the fourth invention, wherein the voltage conversion means is a piece from the output voltage of the second power generation means to the output voltage of the first power generation means. Voltage conversion is performed in the direction.

  A sixth invention is a vehicle power supply system according to the fifth invention, wherein the voltage conversion means performs voltage conversion only during deceleration.

  The seventh invention is a vehicle power supply system according to any one of the first to sixth inventions, wherein the electric load that requires electric power only during traveling is an active stabilizer device. The eighth invention is a vehicular power supply system according to any one of the first to sixth inventions, wherein the electric load that requires electric power only when traveling is a variable light distribution type lighting device. It is characterized by that.

  According to the present invention, the efficiency of power generation can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of a vehicle power supply system of the present invention. The vehicle 10 is equipped with various electric loads. In the vehicle power supply system according to the present invention, the electric loads mounted on the vehicle 10 are classified into two groups.

  If the operation mode of the vehicle as a whole is divided into when traveling and when stopped, the electrical load classified into the first group is the electrical load 11 that requires electric power when traveling and / or stopped, and is classified into the second group. The electric load that is used is an electric load 12 that requires electric power only when traveling and does not require electric power when the vehicle is stopped. That is, the electric load 11 is an electric load that needs to be operated when traveling and / or stopped, and the electric load 12 is an electric load that does not need to be operated when stopping and needs to be operated when traveling.

  The first group of electric loads 11 are, for example, an engine control device, a brake control device, an air conditioner, a rear wiper, a mirror heater, a seat heater, an audio and a cigar socket, as a specific example.

  As a specific example, the second group of electric loads 12 may be, for example, an active stabilizer device that adjusts the roll posture of the vehicle by driving an electric motor, a device that stabilizes the running of the vehicle, a steering angle and a vehicle speed. For example, a variable light distribution lighting device that changes the irradiation direction of light such as a headlamp by driving an electric motor according to the above, an electric assist turbo that sends compressed air by driving the electric motor, and the like. Further, a device for improving the safety of the passenger at the time of a vehicle collision, more specifically, an actuator for a pretensioner seat belt, an ignition device for an airbag, and the like may be included in the electric load 12.

  The power source of the electrical load 11 is the first generator 1 and the power storage device 15. The first generator 1 and the power storage device 15 supply power to the electric load 11 via the power line 13. On the other hand, the power source of the electrical load 12 is the second generator 2. The second generator 2 supplies power to the electric load 12 through the power line 14. A power storage device unique to the first generator 1 may be provided between the first generator 1 and the electric load 11, and the second generator is provided between the second generator 2 and the electric load 12. There may be a power storage device unique to 2.

  The first generator 1 is a generator that uses an engine 3 for driving the vehicle as a drive source, and generates electricity by the rotation of the engine 3. The rotation of the engine 3 is transmitted to the first generator 1 by a crank pulley 4 that is coaxially attached to the crankshaft 7 of the engine 3. The electric power generated by the first generator 1 is supplied to the electric load 11 and the power storage device 15 so that the electric load 11 is activated or the power storage device 15 is charged.

  The power storage device 15 also supplies power to the electric load 11 through the power supply line 13 as in the first generator 1. The power storage device 15 may supply power to the electric load 11 when the power supply capacity of the first generator 1 is insufficient, and may supply power to a starter motor for starting the engine 3. Specific examples of the power storage device 15 include a lead battery, a nickel metal hydride battery, a lithium ion battery, and an electric double layer capacitor. The power storage device 15 may be a combination of any of a lead battery, a lithium ion battery, a nickel metal hydride battery, and an electric double layer capacitor.

  In addition, when the first generator 1 is stopped, power can be supplied from the power storage device 15 to the electric load 11. For example, the electric power required when the engine 3 is in a non-operating state of the first generator 1 can be supplied from the power storage device 15 to the electric load 11.

  The second generator 2 is a generator that uses an axle (drive shaft) 8 as a drive source, and generates electricity by the rotation of the axle 8. The rotation of the crankshaft 7 of the engine 3 is transmitted to the differential 6 through a clutch mechanism (not shown) and the transmission 5. The clutch mechanism can disconnect the rotation of the crankshaft 7 of the engine 3 from the transmission 5 and the axle 8. The rotation distributed left and right by the differential 6 is transmitted by the axle 8 to left and right wheels (not shown). In other words, the second generator 2 connected to the axle 8 can generate electric power by the rotation of the wheels (rotation of the axle 8) caused by the traveling of the vehicle. The electric power generated by the second generator 2 is supplied to the electric load 12 and the electric load 12 is activated. Here, the axle 8 is not limited to a single drive shaft, and may include the entire power mechanism from the clutch mechanism to the wheel or a part thereof.

  Therefore, according to the first embodiment of the vehicle power supply system of the present invention shown in FIG. 1, the power supply to the electric load 12 that does not need to be activated when the vehicle is stopped but needs to be activated when the vehicle is traveling is performed only when the vehicle is traveling. The second generator 2 that can generate power and cannot generate power when the vehicle is stopped responds to the electric load 12 that does not need to be operated when the vehicle stops. Since the supply is eliminated, the power generation efficiency of the entire vehicle can be improved. As a result, the size of the first generator 1 can be reduced or the rating can be lowered. It also contributes to improved fuel efficiency. Even if the engine 3 is rotating, the second generator 2 stops generating power when the vehicle stops, so the second generator 2 does not become a load on the first generator 1 when the vehicle stops.

  FIG. 2 is a block diagram showing a second embodiment of the vehicle power supply system of the present invention. In FIG. 2, the description of the same parts and the same reference numerals as those in FIG. 1 is omitted or simplified.

  The one-way DC / DC converter 20 converts the voltage on the power supply line 14 on the second generator 2 side into a voltage by a voltage conversion mechanism inside the DC / DC converter 20 such as a transformer, a switching regulator or a series regulator. Output to one generator 1 side. The voltage conversion direction of the DC / DC converter 20 is only one direction from the second generator 2 side to the first generator 1 side. The converted output voltage is monitored by the ECU 40 or a converter control circuit in the one-way DC / DC converter 20 and controlled so that the output voltage becomes constant. The one-way DC / DC converter 20 converts a voltage on the second generator 2 side into a voltage conversion mode for supplying power to the first generator 1 side, and a stop mode for stopping the voltage conversion and supplying no power. And is set to any mode during operation. By using the voltage conversion function of this one-way DC / DC converter 20, the voltage on the second generator 2 side is converted to supply power to the electric load 11 or charge the power storage device 15. Or it becomes possible to stop voltage conversion and not supply power.

  ECU 40 calculates the charge / discharge current value (battery current value) of power storage device 15 based on the output value of the current sensor that detects the charge / discharge current of power storage device 15. The current detection unit built in the current sensor includes a type that detects current using a Hall element and a type that detects current using a shunt resistor. For example, the current sensor outputs a voltage (0 to 5 V) corresponding to the detected current. Further, ECU 40 calculates the voltage value of power storage device 15 based on the output value of the voltage sensor that detects the voltage of power storage device 15. As is apparent from FIG. 2, the voltage of the power storage device 15 corresponds to the voltage of the power supply line 13 and applied to the electric load 11.

  Further, the ECU 40 detects a current value or a voltage value of the power storage device 15 by using a current sensor that detects a charge / discharge current of the power storage device 15 or a voltage sensor that detects a voltage of the power storage device 15, thereby A “state of charge (SOC)” indicating how much capacity remains is calculated. The charge rate indicates the remaining capacity with respect to the full charge capacity. The ECU 40 calculates the charging rate (remaining capacity) by, for example, integrating (integrating) charging / discharging currents of the power storage device 15. This is because the rate of change over time in the amount of electricity (capacity of the power storage device 15) corresponds to current. Since the remaining capacity corresponds to a value obtained by subtracting the discharge amount discharged from the power storage device 15 from the capacity when the power storage device 15 is fully charged, the ECU 40 connects the power line 13 connected to the power storage device 15 with a current sensor or the like. By monitoring the charge / discharge current of the power storage device 15 and recording the history in the memory, the charge rate (remaining capacity) can be calculated. Note that the initial capacity at the time of full charge is stored in the memory.

  ECU 40 may estimate the charging rate by measuring the minimum value of the voltage of power storage device 15 at the initial stage of discharging. Since it is known that there is a correlation between the minimum value caused by the voltage drop at the initial stage of discharge and the charging rate, the ECU 40 can estimate the charging rate based on the correlation (for example, map data).

  ECU 40 may calculate the charging rate and the full charge capacity by measuring the internal resistance of power storage device 15 at the initial stage of discharging. The internal resistance is calculated from the initial discharge current and the initial discharge voltage. It is known that there is a correlation between the internal resistance and the charging rate, and the internal resistance and the full charge capacity. The ECU 40 refers to the charge rate calculation map for the internal resistance of the power storage device 15 and calculates the charge rate corresponding to the internal resistance of the power storage device 15. The ECU 40 calculates a full charge capacity corresponding to the internal resistance of the power storage device 15 with reference to a calculation map of the full charge capacity with respect to the internal resistance of the power storage device 15.

  If power storage device 15 can be replaced with an electric double layer capacitor and its capacitance is known, ECU 40 charges electric double layer capacitor based on the voltage value and capacitance of electric double layer capacitor. The rate (remaining capacity) can be calculated.

  In addition, charge / discharge control is executed so that the charge rate is maintained within the SOC management range having a predetermined charge rate as an upper and lower limit value. By providing the SOC management range, for example, it is possible to prevent the progress of deterioration of the power storage device 15 due to excessive charging / discharging from being accelerated.

  Further, ECU 40 determines whether or not the vehicle is in a decelerating state based on vehicle state information from another ECU (not shown) or the like. For example, the ECU 40 determines that the vehicle is decelerating when the brake information is in the operating state, and determines that the vehicle is not in the decelerating state when the brake information is not in the operating state. Alternatively, the ECU 40 determines that the vehicle is in the deceleration state when the differential value of the vehicle speed is negative, and determines that the vehicle is not in the deceleration state when the differential value of the vehicle speed is not negative. The deceleration state can also be determined by combining any of vehicle speed information, brake information, engine speed information, and acceleration / deceleration sensor information. For example, it may be determined that the vehicle is decelerating when the brake information is in the activated state and the differential value of the vehicle speed is negative.

  When the ECU 40 determines that the vehicle is in a deceleration state, the ECU 40 changes the operation mode of the one-way DC / DC converter 20 to the voltage on the second generator 2 side and converts the voltage to the first generator 1 side. Set the voltage conversion mode to be supplied. Thereby, when the electric power regenerated by the second generator 2 exceeds the amount of electric power required for the electric load 12, the excess electric power can be supplied to the first generator 1 side.

  The ECU 40 includes a plurality of ROMs such as a ROM for storing control programs and control data, a RAM for temporarily storing control program processing data, a CPU for processing control programs, and an input / output interface for exchanging information with the outside. It is composed of circuit elements. The ECU 40 is not limited to one control unit, and may be a plurality of control units so that control is shared.

  Therefore, according to the second embodiment of the vehicular power supply system of the present invention shown in FIG. 2, as in the first embodiment, the electric load that does not need to be operated when the vehicle is stopped and that needs to be operated when traveling is required. The electric power supply to the electric power 12 can be generated only when the vehicle is running and the second generator 2 that cannot generate electricity when the vehicle is stopped corresponds to the standby current for the electric load 12 that does not need to operate when the vehicle stops. Therefore, the power generation efficiency of the entire vehicle can be improved. As a result, the size of the first generator 1 can be reduced or the rating can be lowered. Even if the engine 3 is rotating, the second generator 2 stops generating power when the vehicle stops, so the second generator 2 does not become a load on the first generator 1 when the vehicle stops.

  Further, according to the second embodiment of the vehicle power supply system of the present invention shown in FIG. 2, the vehicle energy at the time of deceleration can be regenerated by the second generator 2, so that the ECU 40 is decelerating the vehicle 10 or not. If it is determined that the vehicle 10 is decelerating, the operation mode of the one-way DC / DC converter 20 is set to the voltage conversion mode, and the regenerative power recovered by the second generator 2 is It can output to the one generator 1 side, can supply electric power to the electric load 11, and can charge the electrical storage apparatus 15. FIG. As a result, the regenerative power recovered by the second generator 2 can be supplied to the first generator 1 side without being wasted due to heat or the like, and the power to be generated by the first generator 1 can be supplied to the second generator 1. Since it can supplement by the regenerative electric power from the generator 2, the efficiency improvement of electric power generation can be achieved. It also contributes to improved fuel efficiency.

  FIG. 3 is a block diagram showing a third embodiment of the vehicle power supply system of the present invention. In FIG. 3, the description of the same parts and the same reference numerals as those in FIGS. 1 and 2 is omitted or simplified.

  When the voltage on the second generator 1 side is higher than the voltage on the first generator 1 side, the bidirectional DC / DC converter 30 is a voltage inside the DC / DC converter 30 such as a transformer, a switching regulator or a series regulator. By the conversion mechanism, the voltage on the second generator 2 side is stepped down and outputted to the first generator 1 side, or the voltage on the first generator 1 side is stepped up and outputted to the second generator 20 side. To do. The converted output voltage is monitored by the ECU 40 or a converter control circuit inside the DC / DC converter 30 and controlled so that the output voltage becomes constant. The bidirectional DC / DC converter 30 performs step-down conversion of the voltage on the second generator 2 side to supply power to the first generator 1 side, and step-up conversion of the voltage on the first generator 1 side. There is a boost mode in which power is supplied to the second generator 2 side and a stop mode in which voltage conversion is stopped and power supply is not performed, and is set to any mode during operation. By using the voltage conversion function of the bidirectional DC / DC converter 30, the voltage on the second generator 2 side can be stepped down to supply power to the electrical load 11 or charge the power storage device 15. Thus, the voltage on the first generator 1 side can be boosted to supply power to the electric load 12, and voltage conversion can be stopped to stop supplying power.

  Therefore, according to the third embodiment of the vehicle power supply system of the present invention shown in FIG. 3, when the operation mode of the bidirectional DC / DC converter 30 is the step-down mode or the stop mode, the same as in the first embodiment. In addition, since it is no longer necessary to supply the electric load 12 that does not need to be operated when the vehicle is stopped, power that is not originally required due to a standby current or the like, the power generation efficiency of the entire vehicle can be improved. As a result, the size of the first generator 1 can be reduced or the rating can be lowered. Even if the engine 3 is rotating, the second generator 2 stops generating power when the vehicle stops, so the second generator 2 does not become a load on the first generator 1 when the vehicle stops. Further, similarly to the second embodiment, when the operation mode of the bidirectional DC / DC converter 30 is the step-down mode, the regenerative power collected by the second generator 2 is output to the first generator 1 side to Power can be supplied to the load 11 or the power storage device 15 can be charged. As a result, the regenerative power recovered by the second generator 2 can be supplied to the first generator 1 side without being wasted due to heat or the like, and the power to be generated by the first generator 1 can be supplied to the second generator 1. Since it can supplement by the regenerative electric power from the generator 2, the efficiency improvement of electric power generation can be achieved. It also contributes to improved fuel efficiency.

  In addition, according to the third embodiment of the vehicle power supply system of the present invention shown in FIG. 3, voltage conversion can be performed from the first generator 1 side to the second generator 2 side. If it is determined whether the power on the second generator 2 side is insufficient while the motor is not decelerating, and if it is determined that the power on the second generator 2 side is insufficient, the bidirectional DC / The operation mode of the DC converter 30 is set to the boost mode, the generated power generated by the first generator 1 or the stored power of the power storage device 15 is supplied to the second generator 2 side, and the electric load 12 is supplied with power. It can be carried out. As a result, it is possible to supply the generated power of the first generator 1 that cannot be charged because the power storage device 15 is fully charged to the second generator 2 side, and the power shortage on the second generator 2 side. Can be supplemented by the electric power from the first generator 1, so that the efficiency of power generation can be improved. It also contributes to improved fuel efficiency.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, the embodiment in which the voltage on the second generator 1 side is higher than the voltage on the first generator 1 side is given as an example of the present invention. The voltage on the two generators 2 side may be higher or the voltage may be the same.

1 is a block diagram showing a first embodiment of a vehicle power supply system of the present invention. It is a block diagram which shows 2nd Embodiment of the vehicle power supply system of this invention. It is a block diagram which shows 3rd Embodiment of the power supply system for vehicles of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st generator 2 2nd generator 3 Engine 4 Crank pulley 7 Crankshaft 8 Axle 11,12 Electric load 15 Power storage device 20,30 DC / DC converter 40 ECU

Claims (8)

Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
Voltage conversion means for performing voltage conversion between the output voltage of the first power generation means and the output voltage of the second power generation means;
The power generation system for vehicles, wherein the second power generation means supplies the generated power to an electric load that requires electric power only when traveling, out of the in-vehicle electric load. Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
Voltage conversion means for performing voltage conversion between the output voltage of the first power generation means and the output voltage of the second power generation means;
The first power generation means does not supply the generated electric power to an electric load that requires electric power only during traveling out of the on-vehicle electric load,
The vehicle power supply system, wherein the second power generation means supplies the generated power to an electric load that requires electric power only when traveling, out of the in-vehicle electric load. 3. The vehicle power supply system according to claim 1, wherein the voltage conversion unit performs voltage conversion in one direction from an output voltage of the second power generation unit to an output voltage of the first power generation unit. The power supply system for a vehicle according to claim 3, wherein the voltage conversion means performs voltage conversion only during deceleration. The vehicle power supply system according to any one of claims 1 to 4, wherein the electric load that requires electric power only when traveling is an active stabilizer device. The vehicle power supply system according to any one of claims 1 to 4, wherein the electric load that requires electric power only when traveling is a variable light distribution type lighting device. Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
The second power generation means supplies the generated power to the active stabilizer device as an electric load that requires electric power only during traveling , out of the in-vehicle electric loads. . Having first and second power generation means for supplying electric power to an in-vehicle electric load;
The first power generation means generates electric power by rotating an engine, and the second power generation means generates electric power by rotating an axle.
The second power generation means supplies the generated electric power to the variable light distribution lighting device as an electric load that requires electric power only during traveling , out of the in-vehicle electric loads. Power system.

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