JP2009303366A - Vehicle power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fuel consumed for generating power. <P>SOLUTION: A controller 12 calculates a differential value FC1 of a fuel consumption amount of an internal combustion engine 3 in a case when a power generator 6 generates power and a case when it does not generate power with a power generation voltage of the power generator 6 as a parameter, and calculates a sum value of a consumption power amount W0 of an electrical component in a minimum voltage value with which the electrical component driven by power of the power generator 6 can operate and a power amount Wdisbat that the battery 11 can discharge. The controller 12 divides the differential value FC1 by the sum value (W0+Wdisbat). Thus, a power fuel consumption coefficient DNC1 is operated at every power generation voltage of the power generator 6. A power generation voltage of the power generator 6 with which the power fuel consumption coefficient DNC1 becomes minimum is specified. The power generator 6 is controlled so that it generates power by specified power generation voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device that controls the operation of a generator that generates electric power when driven by an internal combustion engine.

Generally, a generator is mounted on a vehicle in order to supply electric power to an electrical component or charge a battery. This generator consumes fuel in order to generate electric power when driven by an internal combustion engine. For this reason, proposals have been made to improve the fuel efficiency of vehicles by reducing the fuel consumed by the generator for power generation. As one of such proposals, an increase in fuel consumption per unit power generation amount (for example, 1 W) when the power generation amount of the generator is increased (for example, 100 W) is calculated. There is a vehicular power supply device that drives a generator when the value is smaller than a determination value determined according to the remaining capacity.
JP 2005-12971 A

  As described above, the power supply device for a vehicle is configured to determine whether or not to generate power according to the amount of increase in fuel consumption. When determining whether or not to generate power, the generator No consideration is given to the generated voltage or generated power. In general, the amount of electric power consumed by electrical components and the charge / discharge loss of the battery increase as the power generation voltage of the generator increases. For this reason, according to the conventional vehicle power supply device, the power generation voltage of the generator increases, so that the power consumption of the electrical components and the charge / discharge loss of the battery increase, and the power generation amount of the generator increases. The fuel consumed to generate electricity may not be reduced as expected.

  The present invention has been made in view of the above problems, and an object thereof is to provide a vehicular power supply device that can reliably reduce the fuel consumed to generate power.

  The power supply device for a vehicle according to the present invention calculates the difference value of the fuel consumption amount of the internal combustion engine between when the generator generates power and when it does not, using the power generation voltage of the generator as a parameter, By calculating the sum of the power consumption of the electrical component at the minimum voltage value at which the driven electrical component can operate and the amount of power that the battery can discharge, and dividing the calculated difference value by the sum value, The division value is calculated for each power generation voltage of the generator, the power generation voltage of the power generator that minimizes the calculated division value is specified, and the power generator is controlled to generate power with the specified power generation voltage.

  According to the vehicle power supply device of the present invention, the power generation voltage that minimizes the fuel consumption for power supply is selected while guaranteeing the operation of the electrical components. Can be reduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Vehicle configuration]
First, with reference to FIG. 1, the structure of the vehicle which becomes one Embodiment of this invention with which this invention was applied is demonstrated.

  As shown in FIG. 1, a vehicle 1 according to an embodiment of the present invention includes an internal combustion engine (engine) 3 that drives main drive wheels 2a and 2b, an electric motor 5 that can drive slave drive wheels 4a and 4b, and an internal combustion engine. A generator 6 disposed adjacent to the engine 3 and a speed reducer 7 that transmits the driving force of the electric motor 5 to the driven wheels 4a and 4b are provided. The generator 6 is connected to the inverter 9 and the switching mechanism 10 via the power harness 8, and generates electric power generated by being driven by the internal combustion engine 3 via the electric motor 5 and the switching mechanism 10 via the inverter 9. It can supply to the battery 11 for electrical components. The operation of the generator 6, the inverter 9, and the switching mechanism 10 is controlled by the controller 12. The battery 11 is provided with a detection sensor 11a for detecting the storage state of the battery 11, and information detected by the detection sensor 11a is input to the controller 12.

[Power generation control processing]
In the vehicle 1 according to an embodiment of the present invention, the controller 6 executes the power generation control process shown below, whereby the generator 6 that minimizes the fuel consumption for supplying power while guaranteeing the operation of the electrical components. Select the generated voltage. Hereinafter, the movement of the controller 12 when executing this power generation control process will be described.

The power consumption of the electrical component when the generated power is supplied from the generator 6 at the power generation voltage V0 (for example, 12.5 V) is the minimum power consumption W0 (see FIG. 2), that is, the minimum power required for the operation of the electrical component When defined as an amount, the minimum power consumption amount W0 is expressed as in Equation 1 below. The parameter I0 in Equation 1 indicates the generated current of the generator 6.

In addition, when the generated power is supplied from the generator 6 with the generated voltage V1 (> V0) larger than the generated voltage V0, the power consumption amount W1 of the electrical component is expressed as the following Expression 2. Therefore, the difference value (W1−W0) between the power consumption amount W1 and the minimum power consumption amount W0 becomes an unnecessary power consumption increment, and increases as the power generation voltage of the generator 6 increases as shown in FIG. In addition, the parameters I1 and R in Formula 2 indicate the generated current of the generator 6 and the electrical resistance of the vehicle electrical components, respectively.

On the other hand, the amount of electric power Wbat charged in the battery 11 is expressed as Equation 3 below, where Ibat is the charging current of the battery 11. Further, the amount of electric power Wdisbat that can be supplied by the battery 11 at the time of discharging (voltage V0) is expressed as the following Equation 4, where the charge / discharge coulomb efficiency of the battery 11 is ηCbat. Therefore, the difference value (Wbat−Wdisbat) between the power amount Wbat and the power amount Wdisbat becomes a power loss accompanying charging / discharging, and increases as the power generation voltage of the generator 6 increases as shown in FIG.

From the above, if the difference in fuel consumption when the generator 6 does not generate power and when the battery 11 is charged while generating power and generating power as described above is defined as FC1, The electric fuel consumption coefficient DNC1 of the machine 6 is expressed as the following Expression 5, and changes according to the generated voltage as shown in FIG.

  Therefore, in the present embodiment, the controller 12 controls the power generation operation of the generator 6 according to the power fuel consumption coefficient DNC1. Hereinafter, with reference to the flowchart shown in FIG. 4, the power generation control process of the generator 6 according to the power fuel consumption coefficient DNC1 will be described. The flowchart shown in FIG. 4 starts at the timing when driving of the internal combustion engine 3 starts, and the power generation control process proceeds to the process of step S1.

  In the process of step S1, the controller 12 detects the remaining capacity (State Of Charge: SOC) of the battery 11 via the detection sensor 11a. Thereby, the process of step S1 is completed and a power generation control process progresses to the process of step S2.

  In the process of step S2, the controller 12 calculates the power fuel consumption coefficient DNC1 of the generator 6 using Equation 5 using the generated voltage of the generator 6 as a parameter. The process of step S2 may be executed in advance and the execution result may be stored. FIG. 5 is a diagram showing the relationship between the power generation voltage calculated when the rotational speed of the internal combustion engine is 1000 and 2000 rpm and the power fuel consumption coefficient DNC1. Thereby, the process of step S2 is completed and the power generation control process proceeds to the process of step S3.

  In the process of step S3, the controller 12 calculates a power generation permission DNC1 (determination threshold) for determining whether to generate power based on the remaining capacity of the battery 11 detected by the process of step S1. Specifically, as shown in FIG. 6, when the remaining capacity (battery SOC) of the battery 11 is equal to or greater than a predetermined value Vmax, the controller 12 is configured to avoid deterioration of the battery 11 due to charging. The power generation permission DNC1 is set to 0 so that power generation is not performed. On the other hand, when the remaining capacity of the battery 11 is equal to or less than the predetermined value Vmin (<Vmax), the controller 12 sets the power generation permission DNC1 large so as to always generate power in order not to deteriorate the battery 11. When the remaining capacity of the battery 11 is between the predetermined value Vmin and the predetermined value Vmax, the larger the remaining capacity is, the more power is left for the discharge. Therefore, the controller 12 increases the remaining capacity of the battery 11. Accordingly, the power generation permission DNC 11 is set small. Thereby, the process of step S3 is completed and the power generation control process proceeds to the process of step S4.

  In the process of step S4, the controller 12 determines whether or not the power fuel consumption coefficient DNC1 of the generator 6 calculated by the process of step S2 is less than or equal to the power generation permission DNC1 set by the process of step S3. As a result of the determination, if the power fuel consumption coefficient DNC1 is not less than or equal to the power generation permission DNC1, the controller 12 advances the power generation control process to the process of step S5. On the other hand, when the power fuel consumption coefficient DNC1 is equal to or less than the power generation permission DNC1, the controller 12 advances the power generation control process to the process of step S6.

  In the process of step S5, the controller 12 controls the generator 6 so as not to generate power. Thereby, the process of step S5 is completed and the power generation control process returns to the process of step S1.

  In the process of step S6, the controller 12 calculates a power generation voltage at which the power fuel consumption coefficient DNC1 is minimized based on the calculation result of step S2, and controls the generator 6 to generate power at the calculated power generation voltage. Thereby, the process of step S6 is completed and the power generation control process returns to the process of step S1.

  As is apparent from the above description, in the electric vehicle according to the embodiment of the present invention, the controller 12 uses the power generation voltage of the power generator 6 as a parameter and the internal combustion engine when the power generator 6 generates power and when it does not generate power. 3 is calculated, and the power consumption amount W0 of the electrical component at the minimum voltage value at which the electrical component driven by the power of the generator 6 can operate and the amount of power that the battery 11 can discharge. Calculate the sum of Wdisbat. Then, the controller 12 divides the calculated difference value FC1 by the sum value (W0 + Wdisbat) to calculate the power fuel consumption coefficient DNC1 for each power generation voltage of the generator 6, and the calculated power fuel consumption coefficient DNC1 is minimized. The power generation voltage of the power generator 6 is specified, and the power generator 6 is controlled to generate power at the specified power generation voltage. According to such a configuration, the controller 12 selects the power generation voltage that minimizes the amount of fuel consumed for power supply while guaranteeing the operation of the electrical components, so that the fuel consumed for power generation can be ensured. Can be reduced.

  Further, as apparent from Equations 2 and 3, since the difference value FC1 changes according to the generated voltage of the generator 6, it is considered that the generated voltage of the generator 6 changes according to the generated voltage. As shown in FIG. 7, the power generation voltage of the power generator 6 can be determined in consideration of the power generation efficiency of the power generator 6 that varies depending on the power generated. In addition, since the change in the charge / discharge power loss of the battery 11 caused by the change in the power generation voltage of the generator 6 is calculated as shown in Formula 4, the power generation efficiency of the generator 6 that has the best power generation efficiency in consideration of the charge / discharge loss of the battery 11 is calculated. The generated voltage can be determined.

  In the vehicle 1 according to an embodiment of the present invention, the controller 12 sets the power generation permission DNC1 that decreases as the remaining capacity of the battery 11 increases, and performs power generation when the power fuel consumption coefficient DNC1 is equal to or lower than the power generation permission DNC1. When the power fuel consumption coefficient DNC1 is equal to or greater than the power generation permission DNC1, power generation is not performed. According to such a configuration, when the remaining capacity of the battery 11 has a margin, power is generated with a power generation voltage with good power generation efficiency, and when the remaining capacity of the battery 11 has no margin, even with a power generation voltage with relatively poor power generation efficiency. Since power generation is performed, it is possible to achieve both the charge / discharge balance of the battery 11 and the improvement of fuel consumption.

  As mentioned above, although embodiment which applied the invention made by this inventor was described, this invention is not limited by the description and drawing which make a part of indication of this invention by this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

It is a mimetic diagram showing composition of vehicles used as one embodiment of the present invention. It is a figure which shows the change of the electric energy consumption of the electrical component accompanying the change of the electric power generation voltage of a generator, and the electric power loss amount of a battery. It is a figure which shows the change of the electric power fuel consumption coefficient accompanying the change of the electric power generation voltage of a generator. It is a flowchart figure which shows the flow of the electric power generation control process used as embodiment of this invention. It is a figure which shows the example of a calculation result of the electric power fuel consumption coefficient which used the generated voltage as a parameter. It is a figure which shows the relationship between the remaining capacity of a battery and a determination threshold value. It is a contour diagram which shows the relationship between the rotation speed of an internal combustion engine, generated electric current, and electric power generation efficiency.

Explanation of symbols

1: Vehicles 2a, 2b: Main drive wheels 3: Internal combustion engine (engine)
4a, 4b: Sub driven wheel 5: Electric motor 6: Generator 7: Reducer 8: Power harness 9: Inverter 10: Switching mechanism 11: Battery 11a: Detection sensor 12: Controller

Claims (4)

A generator for generating electricity by being driven by an internal combustion engine of the vehicle;
A battery charged by the power generated by the generator;
Control means for controlling the power generation amount of the generator according to the output of the internal combustion engine,
The control means calculates the difference value of the fuel consumption amount of the internal combustion engine when the generator generates and does not perform using the generated voltage of the generator as a parameter, and is driven by the power of the generator By calculating the sum of the power consumption of the electrical component and the amount of power that can be discharged by the battery at the minimum voltage value at which the electrical component can be operated, and dividing the calculated difference value by the sum value The division value is calculated for each generation voltage of the generator, the generation voltage of the generator that minimizes the calculated division value is specified, and the generator is controlled to generate power at the specified generation voltage. A vehicle power supply device characterized by the above. The vehicle power supply device according to claim 1,
The control means is configured to take fuel consumption of the internal combustion engine when the generator generates power in consideration of changes in power consumption of the electrical components and charging power of the battery in accordance with a power generation voltage of the generator. A power supply device for a vehicle characterized by calculating a quantity. In the vehicle power supply device according to claim 1 or 2,
The control means calculates a power amount that can be discharged by the battery in consideration of a change in charge / discharge loss of the battery in accordance with a power generation voltage of the generator.   4. The vehicle power supply device according to claim 1, wherein the control unit compares a determination threshold value set according to a remaining capacity of the battery and a magnitude relationship between the division values. 5. And the said power generator is controlled so that it produces electric power with the power generation voltage specified when the said division value is smaller than the determination threshold value, The power supply device for vehicles characterized by the above-mentioned.

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