JP5272562B2 - Vehicle power generation device - Google Patents

Description

  The present invention includes a generator that generates electric power by the driving force of an engine and supplies charging power to a battery, remaining capacity detection means that detects the remaining capacity of the battery, and increases the output voltage of the generator when the vehicle decelerates. The present invention also relates to a vehicular power generation apparatus including voltage control means for reducing the output voltage of the generator when the remaining capacity of the battery detected by the remaining capacity detecting means when the vehicle is not decelerated is equal to or greater than a predetermined lower limit value.

  Conventionally, as shown in Patent Document 1 below, as an operation mode for setting a target output voltage of a generator that supplies charging power to a battery, a first voltage that promotes charging of the battery and a lower voltage than the first voltage In the voltage control device for a vehicle generator provided with a voltage selection mode for selecting a target output voltage from the second voltage that suppresses the charging of the battery and sets the battery to a discharged state, the remaining capacity of the battery is a predetermined lower limit value ( For example, when the vehicle is decelerating, the target output voltage of the generator is set to the first voltage to determine whether the vehicle is decelerating. While promoting charging, if it is determined that the vehicle is not decelerating, the target output voltage is set to the second voltage to discharge the battery.

According to the voltage control device disclosed in Patent Document 1, the output voltage of the generator is increased when the vehicle is decelerating to charge the battery intensively, thereby improving the fuel efficiency while preventing the battery capacity from decreasing. There is an advantage that can be achieved.
JP 2004-180478 A

  By the way, when performing the voltage control as described in Patent Document 1 in which the output voltage of the generator is switched to a high voltage during deceleration and the battery is intensively charged, the remaining capacity of the battery at the start of charging is as small as possible (that is, charging power). The larger the absorption allowance is, the more efficiently the power generated by the generator during deceleration is absorbed by the battery, so the fuel efficiency improvement effect is expected to increase. For this reason, it can be said that the lower limit value of the remaining battery capacity, which is a condition for performing the voltage switching control as described above, is preferably set as small as possible from the viewpoint of improving fuel efficiency.

  However, if the appearance of deceleration scenes during vehicle driving is very low, reducing the lower limit of the remaining battery capacity as described above will have a small effect on improving fuel efficiency, but rather maintain the remaining battery capacity. It is preferable to ensure the battery life.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide a vehicular power generation device capable of achieving both improvement in fuel efficiency and ensuring of battery life.

In order to solve the above-described problems, the present invention provides a generator that generates electric power by the driving force of an engine and supplies charging power to a battery, a remaining capacity detection unit that detects the remaining capacity of the battery, and a vehicle deceleration Voltage control means for raising the output voltage of the generator when the remaining capacity of the battery detected by the remaining capacity detection means when the vehicle is not decelerated is greater than or equal to a predetermined lower limit value. And a parameter value detecting means for detecting a predetermined parameter value related to the appearance frequency of the deceleration scene of the vehicle, wherein the voltage control means is detected by the parameter value detecting means. The appearance frequency of the deceleration scene is determined based on the parameter value, and the remaining battery capacity is higher when the appearance frequency of the deceleration scene is high than when it is low. Set small lower limit value, the parameter value detected by said parameter value detection means, and counts the number of times the vehicle has shifted to the deceleration state in which the fuel cut is performed from the non-reduction state in a predetermined predetermined time domain It is at least one of the total number of times of transition and the total deceleration time obtained by summing the execution time of fuel cut during deceleration within the predetermined time (Claim 1).

  According to the present invention, the output voltage of the generator is increased when the vehicle is decelerated, and the output voltage is decreased if the remaining capacity of the battery is not less than a predetermined lower limit value when not decelerating. The battery can be intensively charged when the vehicle decelerates within a range that does not fall below, and the fuel efficiency can be improved by using the energy at the time of deceleration without waste in charging the battery.

  In addition, since the lower limit value of the remaining battery capacity is set to be smaller as the appearance frequency of the vehicle deceleration scene determined based on the predetermined parameter value is higher, the vehicle is in an operating state in which deceleration is frequently performed. Sometimes, the power that the battery can absorb at one time by charging (charging power absorption allowance) can be increased, and the energy at the time of deceleration can be more efficiently absorbed by the battery as charging power. Thereby, when the opportunity which can use the energy at the time of deceleration for charge of a battery is fully ensured, the regeneration efficiency of the said energy can be raised more and the fuel consumption performance can be improved further.

  On the other hand, when the appearance frequency of the deceleration scene is low, the lower limit value of the remaining battery capacity is set to a relatively large value, so even if there is little opportunity to use the energy during deceleration for charging the battery, The remaining capacity of the battery can be maintained at a sufficient level, and the remaining capacity of the battery can be prevented from staying at a low level, thereby effectively preventing a decrease in battery life.

Furthermore, in the present invention, at least one of the number of times the vehicle has shifted from the non-decelerating state to the decelerating state within a predetermined time period (number of region transitions) and the total fuel cut time during deceleration (integrated deceleration time). Is adopted as the parameter value, the appearance frequency of the deceleration scene can be appropriately determined based on the parameter value closely related to the appearance frequency of the deceleration scene, and the remaining battery capacity is determined based on the appearance frequency. There is an advantage that the lower limit value of can be set appropriately.

The lower limit of the battery residual capacity are preferably updated every the predetermined time during operation of the vehicle (claim 2).

  According to this configuration, it is possible to set a more appropriate value reflecting the appearance frequency of a relatively recent deceleration scene as the lower limit value of the remaining battery capacity even under circumstances where the driving environment of the vehicle changes variously. There are advantages.

  As described above, according to the present invention, it is possible to provide a vehicular power generation device capable of achieving both improvement in fuel efficiency and securing of battery life.

  FIG. 1 is a block diagram schematically showing a vehicular power generation apparatus according to an embodiment of the present invention. In this figure, 1 is an engine and 3 is a generator. The generator 3 is linked to the engine 1 via a belt 5 wound around the crankshaft 1a of the engine 1, and the generator 3 is rotated as the crankshaft 1a rotates during operation of the engine 1. The drive shaft 3a is rotationally driven.

  The generator 3 has a magnetic pole that is rotationally driven together with the drive shaft 3a, and is configured as a so-called rotating magnetic field type alternator that generates electric power by the rotation of the magnetic pole. Further, the power generation amount of the generator 3 is variably controlled by increasing or decreasing the field current (current for magnetizing the electromagnet in the alternator) based on a command from the controller 20 described later.

  A battery 4 as a power storage device is connected to the generator 3, and a part of the electric power generated by the generator 3 is stored in the battery 4. These generator 3 and battery 4 are, for example, air conditioners, audio devices, lamps such as headlights, and various electrical components including electrical devices such as engine starting and ignition systems (in FIG. 1, this is represented by reference numeral 10). The operating power of the electrical component 10 is covered by the power generated by the generator 3 or the power stored in the battery 4.

  That is, the power generation amount of the generator 3 varies depending on the rotational speed of the engine 1 and the set value of the field current, but when this power generation amount is larger than the total electric load amount of the electrical component 10, the generator 3 Only acts as a power source, and surplus power is supplied to the battery 4 as charging power. On the other hand, when the power generation amount of the generator 3 is smaller than the electrical load amount of the electrical component 10, the operating power of the electrical component 10 is insufficient only by the power generation by the generator 3, so It will be covered by the discharge from.

  Next, a control system of the vehicle power generation device of this embodiment will be described. The vehicle is provided with a controller 20 including a conventionally known CPU and various memories, and the power generation operation of the generator 3 is controlled based on a command from the controller 20.

  Sensors for detecting various state quantities related to driving of the vehicle are electrically connected to the controller 20. Specifically, the controller 20 includes a current sensor 12 that detects a current value input / output to / from the battery 4 (that is, a charge / discharge current value), a vehicle speed sensor 14 that detects the traveling speed of the host vehicle, and an occupant. Are connected to an accelerator opening sensor 15 for detecting the opening degree of an accelerator pedal (not shown) to be depressed by a crank angle sensor 16 for detecting the rotation angle of the crankshaft 1a of the engine 1, and these various sensors. A kind of detected value is inputted to the controller 20 as an electric signal.

  The controller 20 has a remaining capacity detector 21, a parameter value detector 22, and a generator controller 23 as functional elements.

  The remaining capacity detecting unit 21 corresponds to the remaining capacity detecting means according to the present invention and detects the remaining capacity of the battery 4 based on the change in the charge / discharge current of the battery 4.

  The parameter value detection unit 22 corresponds to a parameter value detection unit according to the present invention, and is a predetermined parameter value related to the appearance frequency of a vehicle deceleration scene (that is, a parameter value indicating how often the vehicle is decelerated). ) Is detected. Although details will be described later, in this embodiment, the number of times that the vehicle has shifted from the non-decelerated state to the decelerating state (the number of times of region transition) and the total time during which the vehicle has decelerated (integrated deceleration time) It is detected as a value.

  The generator control unit 23 corresponds to voltage control means according to the present invention, and adjusts the field current of the generator 3 according to the driving state of the vehicle, thereby increasing or decreasing the output voltage of the generator 3. It is. More specifically, the generator control unit 23 increases the output voltage of the generator 3 when the vehicle decelerates to promote charging of the battery 4, and decreases the output voltage of the generator 3 when the vehicle is not decelerated. The battery 4 is configured to be prevented from being charged (that is, the battery 4 is discharged).

  However, even when the generator control unit 23 is not decelerating, if the remaining capacity of the battery 4 detected by the remaining capacity detection unit 21 is smaller than a predetermined lower limit value, the generator 3 outputs the output voltage of the generator 3. There is no control to reduce. In such a configuration, the lower limit value of the remaining battery capacity is set to increase or decrease in inverse proportion to the appearance frequency of the deceleration scene of the vehicle. In other words, the generator control unit 23 determines the appearance frequency of the deceleration scene based on the parameter value detected by the parameter value detection unit 22, and the battery is higher when the appearance frequency of the deceleration scene is higher than when it is lower. The lower limit value of the remaining capacity is set to be small.

  Next, specific contents of the control operation performed by the controller 20 configured as described above will be described based on the flowchart shown in FIG. When the engine 1 is started and the flowchart of FIG. 2 is started, the controller 20 first charges the battery 4 based on the detected values of the current sensor 12, the vehicle speed sensor 14, the accelerator opening sensor 15, and the crank angle sensor 16. A process of reading the discharge current Ib, the traveling speed Vs of the host vehicle, the opening degree θa of the accelerator pedal, and the engine rotational speed Ne is executed (step S1).

  Next, the controller 20 executes a process of calculating the driving time Tr of the vehicle based on a count value such as a timer (not shown) (step S2). The operation time Tr is reset every time the lower limit value Cmin of the remaining battery charge SOC is updated, as shown in steps S12 and S13 described later. Therefore, the value of the operation time Tr is set to the lower limit value Cmin. Is the measurement time from when the engine is started, and when the lower limit Cmin is updated at least once, the measurement time from the previous update is obtained.

  Next, the controller 20 executes a process for calculating the remaining capacity SOC of the battery 4. Specifically, the charging / discharging current Ib of the battery 4 acquired from the current sensor 12 is integrated from the time of starting the engine, for example, to calculate the charging amount or discharging amount with reference to the initial capacity of the battery 4, and thereby obtained. The current battery capacity is acquired as the remaining capacity SOC of the battery 4. The calculation of the remaining battery capacity SOC performed here is performed by the remaining capacity detection unit 21 of the controller 20 as described above.

  Next, the controller 20 executes a process of determining whether or not the driving time Tr of the vehicle acquired in step S2 is shorter than a predetermined time Tr1 (for example, about 10 minutes) (step S4). . And when it determines with YES here and it is confirmed that the driving time Tr has not yet reached predetermined time Tr1, the controller 20 will transfer to the determination process in following step S5-S7, and a vehicle will decelerate. It is determined whether it is in the middle.

  Specifically, in steps S5 to S7, it is first determined whether or not the speed Vs of the host vehicle detected by the vehicle speed sensor 14 is greater than zero (Vs> 0 km / s) (YES in step S5). When it is determined that the host vehicle is not stopped, it is determined whether or not the throttle opening θa detected by the accelerator opening sensor 15 is fully closed (0%) (step). S6). Furthermore, if it is determined YES in step S6 and it is confirmed that the accelerator pedal is in the fully closed state, the engine speed Ne calculated based on the detected value of the crank angle sensor 16 is set to a predetermined value. It is determined whether or not the value is Ne1 or more (step S7). Note that the threshold value Ne1 serving as a determination criterion in step S7 is set to a rotational speed that is the lower limit of the execution region of fuel cut (control to cut fuel supplied to the engine 1) performed at the time of deceleration, and rotation during idling. A value slightly higher than the speed is set.

  If YES is determined in any of the above steps S5 to S7, the controller 20 determines that the vehicle is in a decelerating state and the fuel cut is being executed (step S8), and during the operation time Tr up to the present time In addition, a process of calculating a region transition count Kd indicating how many times the vehicle has transitioned from the non-decelerated state to the decelerated state is executed (step S9). This region transition count Kd is increased by being incremented once each time the vehicle shifts from the non-decelerating state to the decelerating state with its initial value being zero. In other words, as long as the transition from the non-decelerated state to the decelerated state does not occur, the value of the region transition number Kd does not change no matter how many times the step S8 is determined to determine that the vehicle is decelerating. The region transition count Kd is sequentially accumulated every time the vehicle transitions from the non-decelerating state to the decelerating state until the operation time Tr reaches the predetermined time Tr1 (that is, NO is determined in step S4). As shown in step S13, which will be described later, it is reset when a predetermined time Tr1 has elapsed. Note that the calculation of the region transition count Kd performed in step S9 is performed by the parameter value detection unit 22 of the controller 20 as described above. This also applies to the next step S10.

  Next, the controller 20 calculates an accumulated deceleration time Td that indicates how much time in the deceleration state of the operation time Tr up to the present time has existed by integrating the fuel cut execution time at the time of deceleration. The process which performs is performed (step S10). The integrated deceleration time Td is set to zero as an initial value, and increases as the time is incremented every time the vehicle is decelerated. The accumulated deceleration time Td is sequentially accumulated every time the vehicle is decelerated until the operation time Tr reaches the predetermined time Tr1 (that is, NO is determined in step S4), and will be described later in step S13. As shown in FIG. 4, the reset is performed when a predetermined time Tr1 elapses.

  When the region transition count Kd and the accumulated deceleration time Td are calculated as described above, the controller 20 increases the field current of the generator 3 to increase the output voltage (generated voltage) of the generator 3 to the battery 4. A process of setting a predetermined high output value (for example, about 15 V) larger than the terminal voltage (12.5 V) is executed (step S11). Thereby, a relatively large amount of power is supplied from the generator 3 to the battery 4, and charging of the battery 4 is promoted. The output voltage setting process performed here is performed by the generator control unit 23 of the controller 20 as described above. This also applies to step S16 described later. Further, the generator control unit 23 also performs the process of step S12 described later for updating the lower limit value Cmin of the remaining battery capacity SOC.

  Next, the control operation when it is determined NO in step S4 will be described. When it is determined NO in step S4 and it is confirmed that the driving time Tr of the vehicle has reached the predetermined time Tr1, the controller 20 counts the region transition count Kd and the accumulated deceleration time when the predetermined time Tr1 has elapsed. Based on Td, a process of setting a lower limit value Cmin, which is a threshold value when determining the size of the remaining battery charge SOC in step S15 described later, is executed (step S12).

  The lower limit value Cmin of the remaining battery charge SOC set in step S12 is basically set to a smaller value as the number of area transition times Kd increases, as shown in the graph of FIG. However, for example, the cumulative deceleration time Td is short despite the relatively large number of region transition times Kd, or vice versa (that is, the cumulative deceleration time Td is long despite the relatively small number of region transition times Td). The lower limit Cmin obtained is corrected by multiplying the value obtained in inverse proportion to the number of area transitions Kd as described above by multiplying the correction coefficient corresponding to the magnitude of the integrated deceleration time Td. . As described above, in step S12, the lower the lower limit value Cmin of the remaining battery capacity SOC is set, the higher the appearance frequency of the vehicle deceleration scene determined based on the parameter values Kd and Td. Yes.

  When the process of setting the lower limit value Cmin of the remaining battery charge SOC is completed as described above, the controller 20 resets (sets to zero) the operation time Tr, the region transition count Kd, and the accumulated deceleration time Td. Is executed (step S13), and then the process proceeds to the determination process of steps S5 to S7 for checking whether or not the vehicle is decelerating.

  Next, the control operation when it is determined as NO in any of the above steps S5 to S7 will be described. In this case, the controller 20 determines that the vehicle is not decelerating (step S14), and determines whether or not the remaining capacity SOC of the battery 4 calculated in step S8 is equal to or greater than a predetermined lower limit value Cmin. A determination process is executed (step S15). Since the lower limit Cmin serving as the determination threshold here is updated every predetermined time Tr1 in step S12 as described above, the value of the lower limit Cmin is the appearance frequency of a relatively recent deceleration scene. The latest value that reflects is always used.

  When it is determined YES in step S24 and it is confirmed that the remaining capacity SOC of the battery 4 is equal to or higher than the lower limit value Cmin, the controller 20 sets the output voltage of the generator 3 to be approximately the same as the terminal voltage of the battery 4. A process of setting to a low output value of about 5 V is executed (step S16). Thereby, the electric power generated by the generator 3 is not used for charging the battery 4, and the battery 4 is basically in a discharged state.

  On the other hand, when it is determined NO in step S15 and it is confirmed that the remaining capacity SOC of the battery 4 is smaller than the lower limit value Cmin, the voltage reduction process as described above is not performed, and the output voltage of the generator 3 is not performed. Is set to a high output value (15 V) for promoting charging of the battery 4 (step S11).

  As described above, the vehicular power generation apparatus according to the present embodiment includes the generator 3 that generates electric power by the driving force of the engine 1 and supplies charging power to the battery 4, and the remaining capacity that detects the remaining capacity SOC of the battery 4. The remaining capacity detection unit 21 serving as a detecting means, and the output voltage of the generator 3 is increased when the vehicle is decelerated, and the remaining capacity SOC of the battery detected by the remaining capacity detection unit 21 when the vehicle is not decelerating is a predetermined lower limit. If the value is equal to or greater than the value Cmin, the generator control unit 23 as voltage control means for reducing the output voltage of the generator 3 and a predetermined parameter value (Kd, Td) relating to the appearance frequency of the deceleration scene of the vehicle are detected. A parameter value detector 22 as a parameter value detector; Then, the generator control unit 23 determines the appearance frequency of the deceleration scene based on the parameter value detected by the parameter value detection unit 22, and when the appearance frequency of the deceleration scene is high, it is higher than that when the deceleration scene is low. The lower limit value Cmin of the remaining battery capacity SOC is set to be small. According to such a configuration, there is an advantage that it is possible to achieve both improvement in fuel efficiency and securing of the life of the battery 4.

  That is, in the above embodiment, the output voltage of the generator 3 is increased when the vehicle is decelerated (step S11), and the output voltage is decreased if the remaining capacity SOC of the battery 4 is not less than a predetermined lower limit value Cmin when not decelerating. As a result (step S16), the battery 4 can be intensively charged during deceleration of the vehicle within a range where the remaining capacity SOC does not fall below the lower limit value Cmin, and energy during deceleration is not wasted in charging the battery 4. It can be used to improve fuel efficiency.

  In addition, since the lower limit value Cmin of the battery remaining capacity SOC is set to be smaller as the appearance frequency of the vehicle deceleration scene determined based on the predetermined parameter value is higher (step S12), deceleration is frequently performed. In such an operating state, the power that the battery 4 can absorb at one time by charging (charging power absorption allowance) can be expanded, and the energy at the time of deceleration can be absorbed more efficiently as charging power by the battery 4. be able to. Thereby, when the opportunity which can use the energy at the time of deceleration for charge of the battery 4 is fully ensured, the regeneration efficiency of the said energy can be raised more and the fuel consumption performance can be improved further.

  On the other hand, when the appearance frequency of the deceleration scene is low, the lower limit value Cmin of the remaining battery capacity SOC is set to be relatively large, and therefore there is little opportunity to use the energy during deceleration for charging the battery 4. However, the remaining capacity SOC of the battery 4 can be maintained at a sufficient level, and it is possible to effectively prevent the life of the battery 4 from being reduced by avoiding that the remaining capacity SOC remains at a low level.

  That is, when the appearance frequency of the deceleration scene is low, there are few opportunities to use the energy at the time of deceleration for charging the battery 4, and therefore the charging power absorbed at one time by reducing the lower limit value Cmin of the remaining battery charge SOC is reduced. Even if it expands, improvement in fuel consumption performance cannot be expected so much, and there is a concern that the life of the battery 4 may be shortened if the remaining capacity SOC remains at a low level. On the other hand, in the above configuration, since the lower limit Cmin is set large when the appearance frequency of the deceleration scene is low, the effect of improving the fuel efficiency is small. There is an advantage that the capacity SOC can be maintained at a sufficient level and the lifetime can be appropriately secured.

  Further, in the above embodiment, the predetermined parameter value related to the appearance frequency of the deceleration scene is the region transition count Kd, which is the number of times the vehicle has transitioned from the non-deceleration state to the deceleration state, and the time when the vehicle has entered the deceleration state. Since the total deceleration time Td consisting of the total is detected by the parameter value detection unit 22, it is appropriate based on the parameter value closely related to the appearance frequency of the deceleration scene, such as the region transition count Kd and the total deceleration time Td. Thus, there is an advantage that the appearance frequency of the deceleration scene can be determined and the lower limit value Cmin of the remaining battery charge SOC can be appropriately set based on the appearance frequency.

  In the above embodiment, the lower limit value Cmin of the remaining battery charge SOC is updated every predetermined time Tr1 during driving of the vehicle, so that the driving environment of the vehicle changes variously. However, there is an advantage that a more appropriate value reflecting the appearance frequency of a relatively recent deceleration scene can be set as the lower limit Cmin.

  In the above embodiment, the vehicle is based on both the region transition count Kd, which is the number of times the vehicle transitions from the non-deceleration state to the deceleration state, and the integrated deceleration time Td, which is the total time that the vehicle is in the deceleration state. Although the appearance frequency of the deceleration scene is determined, the appearance frequency of the deceleration scene may be determined based on one of the region transition count Kd and the integrated deceleration time Td.

  Also, for example, in a vehicle with a car navigation system, when the occupant uses the car navigation system to set a predetermined travel route, the environment on the travel route (for example, an urban area or a suburb, traffic congestion) The appearance frequency of the deceleration scene may be predicted on the basis of whether or not it is.

1 is a block diagram schematically showing a vehicle power generation device according to an embodiment of the present invention. It is a flowchart which shows the specific content of the control action of the said vehicle electric power generating apparatus. It is a graph which shows the relationship between the appearance frequency of a deceleration scene, and the lower limit of battery remaining capacity.

Explanation of symbols

1 Engine 3 Generator 4 Battery 21 Remaining Capacity Detection Unit (Remaining Capacity Detection Means)
22 Parameter value detector (parameter value detector)
23 Generator control section (voltage control means)
SOC (Battery) remaining capacity Cmin Lower limit value Kd Number of transitions to region Td Total deceleration time

Claims (2)

A generator that generates electric power by the driving force of the engine and supplies charging power to the battery, a remaining capacity detection means that detects the remaining capacity of the battery, and increases the output voltage of the generator when the vehicle decelerates. A vehicle power generator comprising: voltage control means for reducing the output voltage of the generator when the remaining capacity of the battery detected by the remaining capacity detection means during deceleration is equal to or greater than a predetermined lower limit value,
Parameter value detecting means for detecting a predetermined parameter value related to the appearance frequency of the deceleration scene of the vehicle,
The voltage control means determines the appearance frequency of the deceleration scene based on the parameter value detected by the parameter value detection means, and the lower limit of the remaining battery capacity is lower when the appearance frequency of the deceleration scene is high than when it is low. Set a smaller value ,
The parameter value detected by the parameter value detecting means includes the number of times of region transition obtained by counting the number of times the vehicle has shifted from the non-decelerating state to the decelerating state in which fuel cut is executed within a predetermined time, and the predetermined time A vehicle power generation device characterized in that the vehicle power generation device is at least one of the total deceleration times obtained by adding up the fuel cut execution times during deceleration . The vehicular power generator according to claim 1 ,
The battery the lower limit of the remaining capacity vehicle generator apparatus characterized by being updated every the predetermined time during operation of the vehicle.

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