JP5115717B2 - Vehicle power generation control device - Google Patents

Description

  The present invention relates to a vehicle power generation control device, and more particularly to a control technology for a power generation voltage of a generator for charging power storage means mounted on a vehicle.

  A vehicle generally includes a battery (power storage means) as a power supply source for electric devices such as lamps, and a generator (alternator) that is driven by an engine and charges the battery. . The power generation voltage of the generator is controlled so that the charge amount of the battery becomes equal to or greater than a target value (target charge amount). In such a vehicle, regeneration is performed to save energy by converting kinetic energy into electrical energy during deceleration and collecting it and storing it in a battery, and using the energy stored in the battery for other than deceleration. Further, in order to accurately grasp the charge amount of the battery, a technique has been developed in which the battery is fully charged once the engine is started and the battery is fully charged when the charging current to the battery is saturated.

  With such a full charge determination method, full charge cannot be determined until the charging current to the battery saturates when the engine is started. It becomes difficult. Therefore, the regeneration efficiency is lowered, resulting in a reduction in fuel consumption. This problem becomes prominent particularly when full charge determination is frequently performed by repeatedly starting and stopping the engine in a short time.

Therefore, in order to quickly end the full charge determination, a method of setting the target charge amount of the battery to a high value in advance can be considered. However, if the target charge amount is set to a high value in advance as described above, the charging opportunities increase when the charge amount of the battery is relatively high, so the charge efficiency of the battery decreases, and the regeneration efficiency is as high as intended. Does not improve.
In order to solve the above problem, the full charge determination at the time of engine start is not performed, the engine stop time is measured, and the amount of discharge from the battery corresponding to this stop time is subtracted, thereby Some estimate the amount of charge (Patent Document 1).
JP 2006-230102 A

  However, in the technique of the above-mentioned Patent Document 1, it is possible to estimate the charge amount of the battery in the case of normal vehicle leaving, but for example, when using an electric device mounted on the vehicle when the engine is stopped, When the power is consumed by the standby power of the retrofit electric device, the charge amount of the battery is estimated to be higher than the actual amount. Even if the battery is charged later based on the estimated value of the battery charge that is higher than the actual value, the charge of the battery decreases, and eventually the battery becomes overdischarged and the starting failure or the battery There is a risk of reducing the life.

  The present invention has been made to solve such a problem. The object of the present invention is to quickly control the power generation voltage to an appropriate power generation voltage from the start of charging to improve the regeneration efficiency, and to prevent over-discharge of the power storage means. An object of the present invention is to provide a vehicle power generation control device that can be avoided.

In order to achieve the above object, the invention of claim 1 is for a vehicle that generates power by driving an internal combustion engine mounted on the vehicle and determines a power generation voltage for supplying electric power to the electric load and power storage means of the vehicle. A power generation control device for detecting a storage amount of the storage means based on integration of input / output current to the storage means; and a power generation voltage when the storage amount detection means detects a predetermined storage amount A power generation voltage lowering means for reducing the internal combustion engine, an internal resistance detecting means for detecting the internal resistance of the power storage means based on the starting current, the starting voltage and the temperature of the power storage means, and the stored value of the power storage amount is volatilized. a power storage amount stored value volatilization detecting means for detecting that it has, if the internal resistance detected by the internal resistance detecting means is a predetermined or more, as well as prohibiting the reduction in the power generation voltage by the power generation voltage lowering means, the storage amount SL When the value volatilization detecting means detects the volatilization of the charged amount of stored value, characterized by comprising a power generation voltage drop inhibiting means for inhibiting the degradation of the power generation voltage by the power generation voltage drop means.

According to a second aspect of the present invention, in the first aspect, when the power generation voltage reduction is prohibited by the power generation voltage reduction prohibiting means, the storage amount of the power storage means is stored based on the input / output current and voltage of the power storage means. it characterized by further comprising a charged amount stored value initializing means for initializing the value.

According to the vehicle power generation control device of the first aspect of the present invention, the power generation voltage lowering control is performed based on the amount of power stored in the power storage means detected by integrating the input / output current to the power storage means. The amount of stored electricity can be quickly grasped from the start and can be controlled to an appropriate charging pressure, and the regeneration efficiency can be improved.
Further, in the present invention, when the internal resistance of the power storage means is greater than or equal to a predetermined value during startup of the internal combustion engine, a decrease in the generated voltage is prohibited. For example, even when electric power is consumed by an electric load when the vehicle is left unattended, for example, the charging voltage of the power storage means can be ensured and the power storage means can be prevented from being overdischarged. In addition, since the decrease in power generation voltage is prohibited even when the stored value of the stored amount of electricity has been volatilized, it is possible to prevent an erroneous decrease in power generation due to the volatilization of the stored amount of stored amount, and the storage means to be in an overdischarge state. This can be avoided more reliably.

  According to the vehicle power generation control device of claim 2 of the present invention, when the power generation voltage reduction prohibiting unit prohibits the power generation voltage from being reduced, the power storage amount of the power storage unit is determined based on the input / output current and voltage of the power storage unit. Since the stored value is initialized, for example, even when power is consumed by an electric load when the vehicle is left unattended, an error in the stored value of the stored power amount is eliminated, and the stored power amount can be accurately grasped. Accordingly, it is possible to accurately control the decrease in the generated voltage based on the amount of power stored in the subsequent power storage means.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a vehicle power generation device according to the present embodiment.
As shown in FIG. 1, the vehicle of the present embodiment includes an alternator (power generation means) 1 and a battery (power storage means) 2 as power supply devices. The alternator 1 is electrically connected in parallel with an electric device (vehicle electric load) 3 such as a headlamp and a battery 2. The alternator 1 is driven by an engine (internal combustion engine) 4 for driving the vehicle to generate electric power, and supplies electric power to an electric device 3 such as a headlamp, and supplies electric power to the battery 2 and charges it.

  The ECU 10 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and a clock, and includes an accelerator pedal sensor 11, a vehicle speed sensor 12, and an engine that detect the accelerator opening. The detection information from each sensor such as the rotation speed sensor 13 and the battery temperature sensor 14, the operation signal of the start switch 15 of the engine 4, the voltage of the battery 2 and the charging current are input.

On the other hand, the alternator 1 is connected to the output side of the ECU 10, and a control signal is sent to the alternator 1 to control the generated voltage.
2 to 5 are flowcharts showing the control procedure of the power generation voltage of the alternator 1 in the ECU 10. This routine is started when the engine is started.
In step S10, a control signal is output to the alternator 1 so that the generated voltage is 14.4V. Then, the process proceeds to step S20.

In step S20, a backup memory area SUM value Σmem corresponding to the use amount of a backup memory described later is calculated. Then, the process proceeds to step S30.
In step S30, it is determined whether or not Σmem calculated in step S20 matches a later-described saved SUM value (power storage amount storage value volatilization detecting means). If they match, the process proceeds to step S40.

In step S40, the current time Tnow is fetched from the clock. Then, the process proceeds to step S50.
In step S50, a soak time (vehicle leaving time) Tsoak is calculated from the current time Tow read in step S40 and the previous engine stop time Tod stored in step S190 described later. Specifically, Tsoak = Tnow−Told is calculated. Then, the process proceeds to step S60.

In step S60, it is determined whether or not the soak time Tsoak calculated in step S50 exceeds 48 hours. If it has not exceeded 48 hours, the process proceeds to step S70.
In step S70, it is determined whether or not a power generation voltage drop prohibition flag described later is set (1). If the generated voltage drop prohibition flag is not set, the process proceeds to step S80.

In step S80, a control signal is output to the alternator 1 so that the generated voltage is 14.4V. The generated voltage 14.4V is a reference value of the generated voltage when the battery temperature is 20 ° C., and is actually increased or decreased from the generated voltage 14.4V according to the battery temperature input by the battery temperature sensor 14. . Then, the process proceeds to Step 90.
In step S90, it is determined whether or not the start switch 15 of the engine 1 is ON. If the start switch 15 is ON, the process proceeds to step S100.

In step S100, the starting battery current Ist is captured. Then, the process proceeds to step S110.
In step S110, the starting battery voltage Vst is captured. Then, the process proceeds to step S120.
In step S120, the battery internal resistance Rbat is calculated from the starting battery current Ist captured in step S100 and the starting battery voltage Vst read in step S110. Specifically, Rbat = Vst / Ist is calculated (internal resistance detection means). Then, the process returns to step S90.

On the other hand, if it is determined in step S90 that the start switch of the engine 1 is not ON, the process proceeds to step S130.
In step S130, the battery temperature Tmp is taken in from the battery temperature sensor 14. Then, the process proceeds to step S140.
In step S140, a discharge determination internal resistance Rdis (Tmp) is calculated. Specifically, the internal resistance Rdis (Tmp) for discharge determination is obtained by searching from a map stored in advance based on the battery temperature Tmp captured in step S130. Then, the process proceeds to step S150.

In step S150, it is determined whether or not the battery internal resistance Rbat calculated in step S120 is greater than the discharge determination internal resistance Rdis (Tmp) calculated in step S140. If it is determined that the battery internal resistance Rbat is not greater than the discharge determination internal resistance Rdis (Tmp), that is, not greater than the discharge determination internal resistance Rdis (Tmp), the process proceeds to step S160.
In step S160, a subroutine of charge / discharge control execution processing described later is executed. Then, the process proceeds to step S170.

In step S170, it is determined whether or not the engine 4 is stopped by inputting the engine speed from the engine speed sensor 13. If it is in a stopped state, the process proceeds to step S180. If not stopped, the process returns to step S160.
In step S180, the current time Told is fetched from the clock. Then, the process proceeds to step S190.

In step S190, the current time Tod captured in step S180 is set in the backup memory as the engine stop time Tod. Then, the process proceeds to step S200.
In step S200, a later-described discharge amount new is set in the backup memory. Then, the process proceeds to step S210.

In step S210, the generated voltage drop prohibition flag value is set in the backup memory. Then, the process proceeds to step S220.
In step S220, the saved SUM value is calculated and set in the backup memory. Specifically, the saved SUM value is calculated by adding all the address values assigned to the backup memory. Then, this routine ends.

  On the other hand, if it is determined in step S30 that the backup memory area Σmem does not match the saved SUM value, or if it is determined in step S60 that the soak time Tsoak exceeds 48 hours, a decrease in power generation voltage is prohibited in step S70. If it is determined that the flag is being set, or if it is determined in step S150 that the battery internal resistance Rbat is greater than the discharge determination internal resistance Rdis (Tmp), the process proceeds to step S300.

In step S300, the generated voltage drop prohibition flag is set to 1 (ON) (generated voltage decrease prohibiting means). Then, the process proceeds to step S310.
In step S310, the battery current Ibat is captured. Then, the process proceeds to step S320.
In step S320, the battery voltage Vbat is captured. Then, the process proceeds to step S330.

In step S330, it is determined whether or not the battery current Ibat input in step S310 is less than 3A and the battery voltage Vbat input in step S320 is greater than 14V. If the battery current Ibat is less than 3A and the battery voltage Vbat is greater than 14V, the process proceeds to step S340.
In step S340, the discharge amount new of the battery 2 is set to an initial value (power storage amount stored value initialization means). Then, the process proceeds to step S350.

In step S350, the generated voltage drop prohibition flag is cleared to 0 (OFF). Then, the process proceeds to step S160.
If it is determined in step S330 that the battery current Ibat is 3 A or more or the battery voltage Vbat is 14 V or less, the process proceeds to step S360.
In step S360, the engine speed is input from the engine speed sensor 13 to determine whether or not the engine 4 is stopped. If it is in a stopped state, the process returns to step S300. If not stopped, the process proceeds to step S180.

FIG. 6 is a flowchart showing a subroutine of charge / discharge control execution processing executed in step S160 of the main routine.
When this subroutine is started, first, in step S400, the battery current Ibat is captured. Then, the process proceeds to step S410.
In step S410, the discharge amount new of the battery 2 is calculated by the following equation (1).

Discharge amount new = Discharge amount old + Ibat × Ibat capture cycle (1)
Here, as the discharge amount old, the previously calculated discharge amount is read from the backup memory and used. Ibat is the battery current input in step S400, and the Ibat capture period corresponds to the time when the battery current Ibat has flowed since the previous discharge amount old was calculated. Then, the process proceeds to step S420. The discharge amount old is one index of the storage amount of the present invention, and this step corresponds to the storage amount detection means of the present invention.

In step S420, a subroutine for travel state determination processing described later is executed. Then, the process proceeds to step S430.
In step 430, a subroutine of target generation voltage Vtgt calculation processing described later is executed. Then, the process proceeds to step S440.
In step S440, a control signal is output to the alternator 1 so that the target generated voltage Vtgt calculated in step S430 is the generated voltage. Then, this routine is returned.

FIG. 7 is a flowchart showing a subroutine of the running state determination process executed in step S420 of the charge / discharge control execution process.
When this subroutine starts, first, in step S500, the vehicle speed is input from the vehicle speed sensor 12, and it is determined whether or not the vehicle speed is zero. If the vehicle speed is 0, the process proceeds to step S510.

In step S510, it is determined whether or not the engine rotation speed input from the engine rotation speed sensor 13 exceeds a preset idle rotation speed +200 rpm. If it exceeds the idle rotation speed +200 rpm, the process proceeds to step S520.
In step S520, it determines with the driving | running state of the engine 1 being a racing state (racing determination), complete | finishes this subroutine, and returns.

If it is determined in step S510 that the engine rotation speed is equal to or less than the idle rotation speed +200 rpm, the process proceeds to step S530.
In step S530, it determines with the driving | running state of the engine 1 being an idle state (idle determination), complete | finishes this subroutine, and returns.
If it is determined in step S500 that the vehicle speed is not 0, the process proceeds to step S540.

In step S540, the accelerator pedal sensor 11 determines whether or not the accelerator pedal is closed. If the accelerator pedal 11 is closed, the process proceeds to step S550.
In step S550, it is determined that the vehicle is in a deceleration state (deceleration determination). Then, the subroutine ends and returns.

If it is determined in step S540 that the accelerator pedal is not closed, the process proceeds to step S560.
In step S560, it is determined that the vehicle is in a steady travel or acceleration state (steady state / acceleration determination). Then, the subroutine ends and returns.
FIG. 8 is a flowchart showing a subroutine of the target generated voltage Vtgt calculation process executed in step S430 of the charge / discharge control execution process subroutine.

When this subroutine is started, first, in step S600, it is determined whether or not the deceleration is determined in the subroutine of the traveling state determination process. If the deceleration is determined, the process proceeds to step S610.
In step S610, it is determined whether or not a power generation voltage drop prohibition flag is set (1). If the power generation voltage drop prohibition flag is not set, the process proceeds to step S620.

In step S620, it is determined whether or not the vehicle speed VSP> 0 has been experienced even once since engine startup. If VSP> 0 has been experienced even once, that is, if the vehicle has traveled even once since engine startup, the process proceeds to step S630.
In step S630, it is determined whether or not the discharge amount new calculated in step S410 is less than 4 Ah. If it is less than 4 Ah, the process proceeds to step S640.

In step S640, it is determined whether or not idling is determined in the subroutine for travel state determination processing. If the idle determination is made, the process proceeds to step S650.
In step S650, a control signal is output to the alternator 1 so that the reference generated voltage at the battery temperature of 20 ° C. is 13.5V. Then, the subroutine ends and returns.

If it is determined in step S640 that the state is not the idle determination state, the process proceeds to step S660.
In step S660, a control signal is output to the alternator 1 so that the reference generated voltage at the battery temperature of 20 ° C. is 12.5V. Then, the subroutine ends and returns. In addition, control of step S630, S650, and S660 corresponds to the generated voltage reduction means of this invention.

If it is determined in step S610 that the generation voltage reduction prohibition flag is set, if it is determined in step S620 that VSP> 0 has not been experienced, or if it is determined in step S630 that the discharge amount new is 4 Ah or more. If so, the process proceeds to step S670.
In step S670, a control signal is output to the alternator 1 so that the reference generated voltage at the battery temperature of 20 ° C. is 14.3V. Then, the subroutine ends and returns.

If it is determined in step S600 that the vehicle is not in the deceleration determination state, the process proceeds to step S680.
In step S680, a control signal is output so that the reference generated voltage at the battery temperature of 20 ° C. is 14.8V. Then, the subroutine ends and returns.
By controlling as described above, the charge control device of the present embodiment obtains the discharge amount new of the battery 2 by integrating the battery current Ibat (S410), and the alternator 1 according to the discharge amount new and the running state of the vehicle. Is generated (target generated voltage Vtgt calculation processing subroutine). For example, when the amount of discharge of the battery 2 during deceleration is 4 Ah or more, the generated voltage is set to 14.3 V, and when it is less than 4 Ah, it is set to less (12.5 V or 13.5 V).

  Thus, in this embodiment, since the discharge amount of the battery 2 is calculated from the integration of the charge current of the battery 2, the charge amount of the battery 2 is immediately grasped without waiting for the charge current to saturate when starting the engine. It is possible to control the generated voltage quickly and appropriately, and it is possible to improve the regeneration efficiency particularly when the engine 4 is repeatedly started and stopped in a short time.

  In the present embodiment, furthermore, the battery internal resistance Rbat is calculated from the starting battery current Ist and the starting battery voltage Vst during the start of the engine 4 (S120), and the discharge determination in which the internal resistance Rbat is obtained based on the battery temperature Tmp. When the internal resistance Rdis (Tmp) is greater than the internal resistance (S150), the reduction of the generated voltage (set to 12.5V or 13.5V) is prohibited (S300). When the internal resistance Rbat is larger than the discharge determination internal resistance Rdis (Tmp), a full charge determination (whether the battery current Ibat is smaller than 3A and the battery voltage Vbat is larger than 14V) is performed (S330). When the full charge determination is made, the discharge amount new is initialized (S340) and the decrease in the generated voltage is released (S350).

Thus, in the present embodiment, a decrease in the charge amount of the battery 2 is grasped by detecting that the internal resistance at the time of starting the engine is greater than or equal to a predetermined value.
FIG. 9 is a graph showing the relationship between the charge amount of the battery 2 and the internal resistance. The horizontal axis of the graph indicates the amount of battery charge, and the vertical axis indicates the internal resistance value of the battery, showing the relationship at each temperature (° C.) of the battery.

As shown in FIG. 9, the internal resistance value of the battery 2 greatly increases as the charge amount decreases. Therefore, by taking the battery temperature into consideration, at least at a low charge amount close to the start limit, the highly reliable charge can be obtained from the internal resistance value. It is confirmed that the quantity can be estimated.
When the internal resistance of the battery 2 is equal to or greater than a predetermined value, that is, when the charge amount of the battery 2 is reduced, the reduction of the generated voltage is prohibited. Therefore, for example, even when the battery 2 is naturally discharged or when the charge amount of the battery 2 is decreased by using the electric device 3 when the vehicle is left, the decrease in the charge amount of the battery 2 is accurately grasped, and the battery 2 is charged. Since the voltage is secured, it is possible to avoid the battery 2 from being overdischarged. Further, since the discharge amount new is initialized when the internal resistance of the battery 2 is greater than or equal to a predetermined value, the error of the discharge amount new is eliminated, and the subsequent control of the generated voltage can be performed accurately.

  As described above, in the present embodiment, the charge amount of the battery 2 can be quickly grasped at the time of starting the engine, and a decrease in the battery charge amount due to leaving the vehicle or the like can be reliably grasped to control the generated voltage. Since the battery 2 is prevented from being overdischarged, the target charging voltage of the battery 2 can be set low. Thus, by setting the target charging voltage of the battery 2 to be low, efficient charging becomes possible, and regeneration efficiency can be greatly improved.

  Further, in this embodiment, when the backup memory area SUM value Σmem coincides with the saved SUM value, that is, when the backup memory area overflows, a decrease in the generated voltage is prohibited. As a result, it is possible to prevent an erroneous reduction in power generation due to the volatilization of the amount of power stored in the backup memory, and to more reliably avoid the battery 2 from being overdischarged.

1 is a schematic configuration diagram of a power generation device for a vehicle according to an embodiment of the present invention. It is a flowchart which shows the control point of the electric power generation voltage of an alternator. It is a flowchart which shows the control point of the electric power generation voltage of an alternator. It is a flowchart which shows the control point of the electric power generation voltage of an alternator. It is a flowchart which shows the control point of the electric power generation voltage of an alternator. It is a flowchart which shows the subroutine of charging / discharging control execution processing. It is a flowchart which shows the subroutine of a driving | running | working state determination process. It is a flowchart which shows the subroutine of a target electric power generation voltage calculation process. It is a graph which shows the relationship between the charge amount of a battery, and internal resistance.

Explanation of symbols

1 Alternator 2 Battery 4 Engine 10 ECU

Claims (2)

A vehicle power generation control device that generates power by driving an internal combustion engine mounted on a vehicle and determines a power generation voltage for supplying electric power to the electric load and power storage means of the vehicle,
A storage amount detection means for detecting a storage amount of the storage means based on integration of input / output currents to the storage means;
Power generation voltage lowering means for lowering the power generation voltage when the power storage amount detection means detects a predetermined power storage amount;
An internal resistance detecting means for detecting an internal resistance of the power storage means based on a starting current, a starting voltage and a temperature of the power storage means during the start of the internal combustion engine;
A storage amount storage value volatilization detection means for detecting that the storage value of the storage amount has volatilized;
When the internal resistance detected by the internal resistance detecting means is greater than or equal to a predetermined value, the power generation voltage lowering means prohibits the power generation voltage from being lowered, and the power storage amount storage value volatilization detection means is the storage amount storage value. When the volatilization of the power generation is detected, the generated voltage drop prohibiting means for prohibiting the decrease in the generated voltage by the generated voltage reducing means;
A vehicle power generation control device comprising:   A storage amount storage value that initializes a storage value of a storage amount of the power storage unit based on an input / output current and a voltage of the power storage unit when a decrease in the generated voltage is prohibited by the power generation voltage decrease prohibition unit The vehicle power generation control device according to claim 1, further comprising initialization means.

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