JP6011716B2 - Vehicle power generation control device and power generation control method - Google Patents

Description

  The present invention relates to a vehicle power generation control device and a power generation control method.

  In JP2005-80396A, in a vehicle equipped with a generator capable of changing the power generation voltage, the charge amount of the battery is estimated based on the current flowing into the battery at the time of charging, and the charge amount of the battery becomes the target charge amount after the engine is started. Until now, a power generation control device that performs charging at a high voltage is disclosed.

  Since the relationship between the charge amount of the battery and the charge current varies depending on the state of the battery, the above device corrects the current value for determining that the target charge amount has been reached based on the battery voltage and temperature, and charges the battery. The estimation accuracy of quantity is improved.

  The relationship between the charge amount of the battery and the charge current also varies depending on the discharge state of the battery before the start of charging. For example, if the state where the discharge current is small continues for a long time, the charging performance of the battery is lowered, and the amount of charge is reduced even if the charging current is the same.

  In such a case, if the current value determined to have reached the target charge amount based on the discharge state of the battery before the start of charging is not corrected, the target charge amount has been reached even though the battery charge amount is small. There is a problem that the battery is insufficiently charged.

  The present invention has been made in view of such technical problems, and an object thereof is to improve the estimation accuracy of the battery charge amount and prevent the battery from becoming insufficiently charged.

  According to an aspect of the present invention, there is provided a vehicle including: a generator driven by an engine; a battery charged by power generated by the generator; and a current detection unit that detects a charge / discharge current of the battery. A power generation control device is provided.

  The power generation control device determines that the amount of charge of the battery has reached the target amount of charge when the charge current of the battery detected by the current detection unit becomes equal to or less than a charge completion determination value.

  In addition, the charging completion determination value is set to be smaller as the discharge current of the battery is smaller before the charging starts.

FIG. 1 is a schematic configuration diagram showing an engine and an auxiliary machine of a vehicle to which the power generation control device according to the first embodiment is applied. FIG. 2 is a flowchart illustrating a processing procedure until the battery charging is completed in the power generation control device according to the first embodiment. FIG. 3 is a flowchart illustrating a processing procedure of variable power generation control of the power generation control device according to the first embodiment. FIG. 4A is a characteristic map showing a charging current when the charging amount is 90% in a battery in which charging performance is not deteriorated. FIG. 4B is a characteristic map showing a charging current when the charging amount is 90% in a battery having a deteriorated charging performance. FIG. 5 is a time chart showing the state of the battery of the vehicle to which the power generation control device according to the first embodiment is applied. FIG. 6 is a flowchart illustrating a processing procedure until the battery charging is completed in the power generation control device according to the second embodiment.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing an engine and an auxiliary machine of a vehicle to which the power generation control device according to the first embodiment is applied.

  The vehicle 1 includes an engine 2, an alternator 3, a battery 4, and a vehicle controller 5.

  The engine 2 is an internal combustion engine that uses gasoline, diesel, or the like as fuel, and the rotational speed, torque, and the like are controlled based on an engine control command from the vehicle controller 5.

The alternator 3 is a generator that can change the generated voltage, and is driven by the engine 2.
The battery 4 is charged with the power generated by the alternator 3. In addition, a current sensor 6 and a temperature sensor 7 are attached to the battery 4.

  A detection signal from the current sensor 6, the temperature sensor 7, the voltage of the battery 4, and the like are input to the vehicle controller 5. The vehicle controller 5 performs various calculations for controlling the engine 2, setting of a target power generation voltage of the alternator 3, estimation of a charge amount of the battery 4, and the like.

  By the way, the vehicle controller 5 changes the target power generation voltage of the alternator 3 as described above, thereby controlling the power generation amount during travel of the vehicle 1 and improving the fuel consumption and power performance.

  Specifically, while the fuel of the engine 2 is being cut while the vehicle 1 is decelerating, the power generation voltage of the alternator 3 is set to a high voltage to efficiently charge the battery 4, and during acceleration when the fuel is not cut. The variable power generation control for stopping the power generation of the alternator 3 and reducing the load on the engine 2 is performed. The high voltage is, for example, 14V.

  However, depending on the amount of charge of the battery 4, it is conceivable that when power generation is stopped, the battery 4 becomes insufficiently charged and the battery 4 deteriorates. Accordingly, when the engine 2 is started, the vehicle controller 5 first sets the power generation voltage of the alternator 3 to a high voltage to charge the battery 4 until the target charge amount is reached, and then performs variable power generation control while charging at a low voltage. I do. The low voltage is a voltage that can supply power to various electrical components without reducing the amount of charge of the battery 4, and is, for example, 13V.

  Here, the vehicle controller 5 estimates the charge amount based on the charge current of the battery 4, but the relationship between the charge amount of the battery 4 and the charge current varies depending on the state of the battery 4.

  Therefore, it is necessary to correct the relationship between the charge amount and the charge current of the battery 4 based on the state of the battery 4 so that the variable power generation control is not actually performed in a state of insufficient charge.

  Therefore, the vehicle controller 5 performs control according to the processing procedure shown in the flowcharts of FIGS. 2 and 3 in order to perform variable power generation control while preventing the battery 4 from being insufficiently charged.

  Hereinafter, the control performed by the vehicle controller 5 will be described in detail according to the flowcharts of FIGS. 2 and 3.

  FIG. 2 is a flowchart illustrating a processing procedure until the battery charging is completed in the power generation control device according to the first embodiment.

  First, the vehicle controller 5 detects the minimum voltage of the battery 4 when the engine 2 is started, and determines whether or not the minimum voltage is greater than or equal to the state determination value (S101). The state determination value is a voltage value by which it can be determined whether or not the charging performance of the battery 4 is degraded, and is, for example, 7V. The charging performance of the battery 4 will be described in detail later.

  When the vehicle controller 5 determines that the minimum voltage of the battery 4 at the time of starting the engine 2 is equal to or higher than the state determination value, the vehicle controller 5 refers to the characteristic map of FIG. Then, based on the voltage of the battery 4 and the temperature of the battery 4 detected by the temperature sensor 7, a charge completion determination value for determining that the charge amount of the battery 4 has reached the target charge amount is set (S102). Migrate processing. The target charge amount is a charge amount that does not promote deterioration of the battery 4 due to insufficient charge, and is, for example, a state where the charge amount is 90%.

  If the vehicle controller 5 determines that the minimum voltage of the battery 4 at the time of starting the engine 2 is smaller than the state determination value, the vehicle controller 5 refers to the characteristic map of FIG. Then, based on the voltage of the battery 4 and the temperature of the battery 4 detected by the temperature sensor 7, a charge completion determination value is set (S103), and the process proceeds to S104.

  FIG. 4a is a characteristic map showing the charging current when the charging amount is 90% in the battery 4 whose charging performance has not deteriorated. FIG. 4B is a characteristic map showing the charging current when the charging amount is 90% in the battery 4 whose charging performance is lowered.

  The relationship between the charging amount of the battery 4 and the charging current varies depending on the voltage and temperature of the battery 4 and also varies depending on the charging performance of the battery 4 as described above.

  The charging performance of the battery 4 varies depending on the discharge state before the charging of the battery 4 is started. For example, the charging performance of the battery 4 decreases as the discharge due to the dark current continues for a long time. The dark current is a minute current that flows when the ignition switch is OFF.

  In the battery 4 in which the charging performance is lowered, even when the voltage and temperature are the same, the charging current when the charging amount is 90% is smaller than that in the battery in which the charging performance is not lowered. For example, when the voltage of the battery 4 is 14V and the temperature is 25 ° C., the charging completion determination value is 10A according to the characteristic map of FIG. 4A, but the charging completion determination value is 3A according to the characteristic map of FIG. 4B. Become.

  Here, before the engine 2 is started, the battery 4 is discharged by a dark current. If this state continues for a long time, the amount of charge of the battery 4 also decreases considerably. Since the electromotive voltage of the battery changes depending on the specific gravity of the battery, when the charge amount of the battery 4 decreases, the voltage of the battery 4 also decreases.

  Therefore, when the minimum voltage of the battery 4 at the time of starting the engine 2 is equal to or higher than the state determination value, the time during which the discharge current is small is short, and it can be determined that the state of the battery 4 has not deteriorated the charging performance. Sets the charge completion determination value with reference to the characteristic map of FIG.

  When the minimum voltage of the battery 4 is smaller than the state determination value, it can be determined that the time during which the discharge current is small is long and the state of the battery 4 is in a state where the charging performance is degraded. To set the charge completion judgment value.

  Thus, the estimation accuracy of the charge amount of the battery 4 can be improved by selecting the characteristic maps (FIGS. 4a and 4b) to be referred to based on the charge performance of the battery 4 and setting the charge completion determination value.

  In S104, the vehicle controller 5 sets the power generation voltage of the alternator 3 to a high voltage (14V), starts charging the battery 4, and proceeds to S105.

  In S105, the vehicle controller 5 determines whether or not the charging current of the battery 4 detected by the current sensor 6 is equal to or less than the charging completion determination value set in S102 or S103.

  When the vehicle controller 5 determines that the charging current is equal to or less than the charging completion determination value, the vehicle controller 5 ends the charging at the high voltage and shifts the process to variable power generation control (END).

  When the vehicle controller 5 determines that the charging current is larger than the charging completion determination value, the vehicle controller 5 repeatedly performs the determination process of S105.

  Next, variable power generation control performed by the vehicle controller 5 will be described.

  FIG. 3 is a flowchart illustrating a processing procedure of variable power generation control of the power generation control device according to the first embodiment.

  First, the vehicle controller 5 sets the power generation voltage of the alternator 3 to a low voltage (13 V) and starts charging the battery 4 (S201).

  Moreover, the vehicle controller 5 starts integration of the charging / discharging current of the battery 4 after starting charging in S201 based on the current of the battery 4 detected by the current sensor 6 (S202).

  Next, the vehicle controller 5 determines whether or not the minimum voltage at the start of the engine 2 is equal to or greater than the state determination value (S203).

  When the vehicle controller 5 determines that the minimum voltage of the battery 4 at the time of starting the engine 2 is equal to or higher than the state determination value, the vehicle controller 5 then sets a discharge allowable charge amount that becomes a lower limit value that allows discharge of the battery 4 to a target charge amount (charge amount 90 %), For example, 88% (S204), and the process proceeds to S206.

  When determining that the minimum voltage of the battery 4 is smaller than the state determination value, the vehicle controller 5 sets the discharge allowable charge amount to 90%, which is the same as the target charge amount (S205), and shifts the process to S206.

  When the minimum voltage of the battery 4 at the time of starting the engine 2 is smaller than the state determination value, the time during which the discharge current is small is long and the charging performance of the battery 4 is deteriorated. Therefore, in such a case, even after the charging with the high voltage is completed, the battery 4 is charged by setting a large lower limit value of the charge amount that allows discharge and maintaining a large charge amount of the battery 4. It can be prevented from becoming insufficient.

  In S206, the vehicle controller 5 determines whether or not the fuel of the engine 2 is cut.

  When the vehicle controller 5 determines that the fuel of the engine 2 is cut, the vehicle controller 5 starts charging the battery 4 with the power generation voltage of the alternator 3 set to a high voltage (S207), and the process proceeds to S208.

  When the vehicle controller 5 determines that the fuel of the engine 2 has not been cut, the vehicle controller 5 repeatedly performs the determination process of S206.

  By charging the battery 4 with a high voltage while the fuel of the engine 2 is cut, the battery 4 can be efficiently charged without affecting the fuel consumption and power performance of the vehicle 1.

  In S208, the vehicle controller 5 determines whether the fuel cut of the engine 2 has been completed.

  When the vehicle controller 5 determines that the fuel cut of the engine 2 has been completed, the vehicle controller 5 stops the power generation of the alternator 3 (S209), and the process proceeds to S210.

  If the vehicle controller 5 determines that the fuel cut of the engine 2 has not been completed, the vehicle controller 5 repeats the determination process of S208.

  In S210, the vehicle controller 5 compares the charge amount of the battery 4 calculated based on the integrated value of the charge / discharge current of the battery 4 with the discharge allowable charge amount set in S204 or S205, and the charge amount of the battery 4 is determined. It is determined whether or not the discharge allowable charge amount is equal to or less.

  If the vehicle controller 5 determines that the charge amount of the battery 4 is equal to or less than the discharge allowable charge amount, the vehicle controller 5 sets the power generation voltage of the alternator 3 to a low voltage and starts charging the battery 4 (S211), and proceeds to S206.

  If the vehicle controller 5 determines that the charge amount of the battery 4 is greater than the discharge allowable charge amount, the vehicle controller 5 repeatedly performs the determination process of S210.

  After the battery 4 is charged at a high voltage during fuel cut, the battery 4 supplies power to various electrical components until the charge amount of the battery 4 becomes equal to or less than the discharge allowable charge amount, and during that time, the alternator 3 generates power. By stopping, the fuel consumption of the vehicle 1 can be improved. In addition, when the charge amount of the battery 4 becomes equal to or less than the discharge allowable charge amount, the charging at the low voltage is resumed, so that the battery 4 can be prevented from being insufficiently charged.

  Next, the operation of the present embodiment will be described with reference to FIG.

  FIG. 5 is a time chart showing the state of the battery of the vehicle to which the power generation control device according to the first embodiment is applied.

  First, when the engine 2 is started, the battery voltage decreases (t1).

  When the alternator 3 starts generating power at 14V, the battery voltage rises to 14V (t1 → t2).

  Thereafter, as the charge amount of the battery 4 increases, the battery current gradually decreases (t2 → t3).

  Here, when the minimum voltage of the battery 4 at the time of starting the engine 2 is higher than the state determination value (7 V), the charging completion determination value is set based on the characteristic map of FIG. When it is lower than the state determination value, the charge completion determination value is set based on the characteristic map of FIG. The time chart of FIG. 5 shows a state in which the minimum voltage of the battery 4 at the time of starting the engine 2 is lower than 7V, and the charge completion determination value is 3A.

  When the battery current reaches 3A, charging at 14V is completed, the generated voltage of the alternator 3 gradually becomes 13V, and the battery voltage decreases to 13V (t3 → t4).

  Since the battery 4 is gradually charged while the power generation voltage of the alternator 3 is 13 V, the battery current integrated value gradually increases after the power generation voltage of the alternator 3 starts switching to 13 V (t3 → t5). . In addition, since the target charge amount of the battery 4 becomes the reference value, the charge amount 90% is 0 As for the battery current integrated value.

  When the fuel of the engine 2 is cut, the power generation voltage of the alternator 3 becomes 14V, and the battery voltage rises to 14V (t5).

  While the fuel is cut, the battery 4 is charged at 14V, so the battery current integrated value increases rapidly (t5 → t6).

  When the fuel cut of the engine 2 is completed (t6), the alternator 3 gradually stops power generation, and the battery voltage decreases (t6 → t7).

  While the power generation of the alternator 3 is stopped, the battery 4 supplies power to various electrical components, so the battery current integrated value decreases to the discharge allowable charge amount (t7 → t8).

  When the minimum voltage of the battery 4 at the time of starting the engine 2 is higher than the state determination value (7 V), the allowable discharge charge amount is, for example, 88% charge amount. When the voltage is lower than 7 V, the allowable discharge charge amount is, for example, 90% charge amount. The time chart of FIG. 5 shows a state in which the minimum voltage of the battery 4 at the time of starting the engine 2 is lower than 7V, and the allowable discharge charge amount is 90% charge amount.

  When the battery current integrated value decreases to the discharge allowable charge amount, the power generation voltage of the alternator 3 becomes 13V, and the battery voltage rises to 13V (t8).

  According to this embodiment, when the minimum voltage of the battery 4 at the time of starting the engine 2 is smaller than the state determination value, the time during which the discharge current of the battery 4 is small before the start of charging is long, and the charging performance of the battery 4 is reduced. Can be determined. Therefore, the estimation accuracy of the battery charge amount can be improved by setting the charge completion determination value that determines that the charge amount has reached the target charge amount as compared with the state in which the charge performance of the battery 4 is not deteriorated. 4 can be prevented from becoming insufficiently charged.

  In addition, when the minimum voltage of the battery 4 at the time of starting the engine 2 is smaller than the state determination value, the discharge allowable charge amount that becomes the lower limit value that allows the battery 4 to be discharged is set large even after the high-voltage charging is completed. And it can prevent that the battery 4 becomes insufficiently charged by maintaining the charging amount of the battery 4 large.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  FIG. 6 is a flowchart illustrating a processing procedure until the battery charging is completed in the power generation control device according to the second embodiment.

  The second embodiment is different from the first embodiment in that the charge completion determination value is set based on the ignition switch OFF time. Hereinafter, the difference from the first embodiment will be mainly described.

  When the ignition switch of the vehicle 1 is turned ON, first, the vehicle controller 5 detects the time from when the ignition switch is turned OFF until it is turned ON, and whether or not the ignition switch OFF time is shorter than the state determination time. Is determined (S301).

  As described above, the charging performance of the battery 4 decreases as the discharge due to the dark current continues for a long time. Therefore, in the state determination time, when the charge completion determination value is set based on the characteristic map of FIG. 4B, the estimation accuracy of the charge amount is higher than when the charge completion determination value is set based on the characteristic map of FIG. 4A. It is time.

  If the vehicle controller 5 determines that the ignition switch OFF time is shorter than the state determination time, the vehicle controller 5 sets a charge completion determination value with reference to the characteristic map of FIG. 4A (S302), and proceeds to S304.

  If the vehicle controller 5 determines that the ignition switch OFF time is equal to or longer than the state determination time, the vehicle controller 5 sets a charge completion determination value with reference to the map of FIG. 4B (S303), and proceeds to S304.

  In S304 and S305, the same processing as S104 and S105 of the first embodiment is performed.

  According to this embodiment, when the ignition switch OFF time is equal to or longer than the state determination time, it can be determined that the time during which the discharge current of the battery 4 is small before the start of charging is long and the charging performance of the battery 4 is degraded. . Therefore, the estimation accuracy of the battery charge amount can be improved by setting the charge completion determination value that determines that the charge amount has reached the target charge amount as compared with the state in which the charge performance of the battery 4 is not deteriorated. 4 can be prevented from becoming insufficiently charged.

  As mentioned above, although embodiment of this invention was described, the said embodiment showed only a part of application example of this invention, and is not the meaning which limits the technical scope of this invention to the specific example of said embodiment. .

  In the above embodiment, the charging completion determination value is set based on two characteristic maps (FIGS. 4a and 4b). For example, even if the charging completion determination value is set based on three or more characteristic maps, Good.

  Further, for example, the charge completion determination value may be corrected by multiplying a correction coefficient (≦ 1) corresponding to the charging performance of the battery 4 with one characteristic map as a reference.

  Further, in S203 to S205 of FIG. 3, the allowable discharge charge amount is set based on the minimum voltage of the battery 4 when the engine 2 is started, but the allowable discharge charge amount is set based on the ignition switch OFF time. Also good. In this case, when the ignition switch OFF time is equal to or longer than the state determination time, it can be determined that the time during which the discharge current of the battery 4 is small before the start of charging is long and the charging performance of the battery 4 is degraded. Therefore, the discharge allowable charge amount is set larger than the state in which the charging performance of the battery 4 is not deteriorated.

  This application claims the priority based on Japanese Patent Application No. 2013-084167 for which it applied to Japan Patent Office on April 12, 2013, and all the content of this application is integrated in this specification by reference.

Claims (5)

A power generation control device for a vehicle, comprising: a generator driven by an engine; a battery charged by power generated by the generator; and current detection means for detecting a charge / discharge current of the battery,
When the charging current of the battery detected by the current detection unit becomes equal to or lower than a charging completion determination value, a charging completion determination unit that determines that the charging amount of the battery has reached a target charging amount;
Determination value setting means for setting the charging completion determination value to be smaller as the time during which the battery discharge current before charging starts is smaller,
A vehicle power generation control device. The power generation control device according to claim 1,
Voltage detecting means for detecting the voltage of the battery;
The determination value setting means is a vehicle power generation control device that determines that the time during which the discharge current is small is longer as the minimum voltage of the battery at the time of engine start detected by the voltage detection means is lower. The power generation control device according to claim 1,
It is equipped with a time measurement means that measures the time from turning off the ignition switch to turning it on,
The power generation control device for a vehicle, wherein the determination value setting means determines that the longer the ignition switch measured by the time measurement means is longer, the longer the time during which the discharge current is smaller. The power generation control device according to any one of claims 1 to 3,
A charge amount calculating means for calculating a charge amount of the battery after the charge completion determining means determines that the charge amount of the battery has reached the target charge amount;
When the calculated charge amount is larger than the discharge allowable charge amount, discharge permitting means for allowing the battery to discharge,
The allowable amount setting means for setting the discharge allowable charge amount larger as the time during which the discharge current of the battery is small before the start of charging is longer,
A vehicle power generation control device. A vehicle power generation control method comprising: a generator driven by an engine; a battery charged by power generated by the generator; and current detection means for detecting a charge / discharge current of the battery,
When the charging current of the battery detected by the current detection unit is equal to or lower than a charging completion determination value, it is determined that the charging amount of the battery has reached a target charging amount,
The power generation control method for a vehicle, wherein the charging completion determination value is set to be smaller as the time during which the battery discharge current is smaller before the start of charging is longer.

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