JP2006094628A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hybrid vehicle capable of reducing fuel consumption while ensuring an energy capacity for charging regenerative energy.
SOLUTION: Regenerative energy predicting means (S2) predicts the amount of regenerative energy obtained at the time of braking based on the vehicle running state, and based on the charged state of the power storage device 3 and the predicted regenerative energy, regenerative charge availability determination means. It is determined whether or not the predicted regenerative energy can be charged in (S3). If it is determined that charging is possible, the first power generation efficiency setting unit (S4) determines the first state corresponding to the state of charge of the power storage device 3. Is set as the target power generation efficiency of the power generation device 7, and when it is determined that charging is not possible, the second power generation efficiency with higher efficiency is targeted until it is determined that the regenerative energy can be charged again. The power generation efficiency is set, and the drive motor 4 and the power generation device 7 are controlled by the charge / discharge control means (S6) to achieve the set target power generation efficiency.
[Selection] Figure 2

Description

  The present invention relates to a control device for a hybrid vehicle.

  Conventionally, in order to reduce the amount of fuel consumed during traveling, when the traveling state in which the electric energy regenerated by the drive motor is predicted to be large, the state of charge (SOC) of the power storage device is lowered to enable sufficient charging. There has been proposed a control device for a hybrid vehicle that performs charge / discharge control so as to change (see Patent Document 1).

There has also been proposed a control device for a hybrid vehicle that operates at a power generation efficiency corresponding to the SOC by associating the state of charge (SOC) of the power storage device with the target value of the power generation efficiency of the vehicle system (see Patent Document 2).
JP-A-10-150701 JP 2002-171604 A

  In the conventional example of Patent Document 1, the energy capacity for charging the regenerated electric energy is achieved. In the conventional example of Patent Document 2, charge / discharge at the power generation efficiency set according to the SOC is realized. It is necessary for the power storage device to have this energy capacity, leading to an increase in size and cost of the power storage device.

  For this reason, in a hybrid vehicle equipped with an energy storage device that cannot satisfy both of the above energy requirements, priority is given to recovery of the energy capacity for regeneration, in which the effect of reducing fuel consumption becomes even greater in many driving scenes. To be done. For example, when the regenerative energy predicted as the vehicle speed rises is large, in order to prioritize the regenerative energy recovery request, discharge is given priority and the SOC of the power storage device is at least used for regenerative energy. The SOC is reduced to a SOC capable of securing the capacity.

  By the way, the target power generation efficiency with respect to the SOC of the power storage device is set so that the target power generation efficiency is low if the SOC of the power storage device is low, and the power generation / charge amount is increased even if the power generation efficiency is low. If the SOC of the power storage device is high, increase the opportunity to travel by supplying power from the power storage device to the drive motor, set the target power generation efficiency high, and generate and charge only when the efficiency is good By doing so, it is common to avoid unnecessary power generation and charging.

  As described above, in the hybrid vehicle in which the SOC of the power storage device and the target power generation efficiency are associated with each other, as described above, when the SOC of the power storage device is reduced to secure regenerative energy, the reduction in the SOC is supported. As a result, the target power generation efficiency is also decreased to increase the power generation / charge amount, and the fuel consumption efficiency until the start of charging of the desired regenerative energy may be reduced.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a hybrid vehicle control device capable of reducing fuel consumption while securing an energy capacity for charging regenerative energy.

  The present invention stores a drive motor for driving a vehicle, a power generation device, power generated by the power generation device and regenerative power generated by the drive motor during vehicle deceleration, and supplies power to the drive motor as necessary. And a regenerative energy amount prediction for predicting a regenerative energy amount obtained at the time of vehicle braking based on a running state of the vehicle. Regenerative charge availability determination means for determining whether or not the predicted regenerative energy amount can be charged based on a charging state of the power storage device and the regenerative energy amount predicted by the regenerative energy amount prediction means; When it is determined that the amount of regenerative energy predicted by the regenerative charge availability determination unit is chargeable, a first value corresponding to the state of charge of the power storage device is determined. When the power generation efficiency is set as the target power generation efficiency of the power generation device and it is determined that the predicted amount of regenerative energy cannot be charged, a second power generation efficiency that is high with respect to the first power generation efficiency is Until it is determined that the regenerative energy can be charged again, the target power generation efficiency setting means for setting the target power generation efficiency of the power generator, and the drive motor so as to realize the target power generation efficiency set by the target power generation efficiency setting means Charging / discharging control means for controlling the power generation device.

  Therefore, in the present invention, the regenerative energy amount predicting means predicts the regenerative energy amount obtained during vehicle braking based on the running state of the vehicle, and the state of charge of the power storage device and the regenerative energy amount predicted by the regenerative energy amount predicting means Based on the above, it is determined whether the regenerative energy amount predicted by the regenerative charge availability determination unit is rechargeable, and the regenerative energy amount predicted by the regenerative charge availability determination unit is determined to be rechargeable by the target power generation efficiency setting unit. If it is determined that the first power generation efficiency according to the state of charge of the power storage device is set as the target power generation efficiency of the power generation device, and it is determined that the predicted amount of regenerative energy cannot be charged, The second power generation efficiency, which is high with respect to the power generation efficiency of 1, is changed to the power generation until it is determined that the regenerative energy can be charged again. Was set as a target power generation efficiency of the location, the drive motor, so as to control the power generator by the charge and discharge control means so as to achieve the target power generation efficiency set by the target power generation efficiency setting means. For this reason, when the predicted regenerative energy cannot be charged sufficiently, it is possible to suppress an increase in power generation / charge amount when lowering the SOC of the power storage device to secure regenerative energy, and to reduce fuel consumption until the start of regenerative energy charging Is possible.

  Hereinafter, the control apparatus of the hybrid vehicle of this invention is demonstrated based on each embodiment.

(First embodiment)
1 to 6 show a first embodiment of a control apparatus for a hybrid vehicle to which the present invention is applied, FIG. 1 is a system configuration diagram of the control apparatus for a hybrid vehicle as the first embodiment, and FIG. 2 is an integrated controller. FIG. 3 to FIG. 6 are flowcharts showing subroutines of the processing flowchart of FIG.

  The hybrid vehicle control device shown in FIG. 1 shows a configuration of a series hybrid vehicle, and its power train is directly connected to the internal combustion engine 1 and converts the output of the internal combustion engine 1 into electric power or starts the engine. The generator 2 is sometimes cranked, and the electric power generated by the electric generator 2 or the electric power stored in the power storage device 3, or the drive motor 4 that is driven by both of these electric powers. The drive wheel 6 is configured to be driven by the torque via the final gear 5. The internal combustion engine 1 and the generator 2 constitute a power generator 7. The power storage device 3 uses a secondary battery such as a nickel metal hydride battery or a lithium ion battery, or a capacitor.

  The power storage device 3 includes a power storage device controller 13. The power storage device controller 13 detects a voltage / current of the power storage device 3, calculates input / output power to the power storage device 3, and outputs the calculated power to the integrated controller 10. . The internal combustion engine 1, the generator 2, and the drive motor 4 are provided with an internal combustion engine controller 11, a generator controller 12, and a drive motor controller 14, which are based on command values from the integrated controller 10. The internal combustion engine 1, the generator 2, and the drive motor 4 are controlled, respectively. That is, the internal combustion engine controller 11 controls the throttle opening of the internal combustion engine 1 so that the torque of the internal combustion engine 1 realizes the internal combustion engine torque command value output from the integrated controller 10. Further, the generator controller 12 performs vector control of the generator 2 so that the rotation speeds of the internal combustion engine 1 and the generator 2 are equal to the rotation speed command value output from the integrated controller 10. The drive motor controller 14 performs vector control of the torque of the drive motor 4 based on the motor torque command value output from the integrated controller 10. A vehicle speed signal from the vehicle speed sensor 15 and an accelerator pedal depression signal from the accelerator pedal depression amount sensor 16 are input to the integrated controller 10, and a navigation system 17 is connected.

  Next, the contents of the charge / discharge control process by the integrated controller 10 of the hybrid vehicle of this embodiment will be described based on the flowchart shown in FIG. This process is repeatedly performed by the integrated controller 10 every predetermined period, for example, every 10 [msec].

When the charge / discharge control process of FIG. 2 is executed, the integrated controller 10 first performs a process of inputting the state of charge SOC of the power storage device 3 (the ratio of the dischargeable capacity to the total capacity) (step S1). This process is based on an output from a current sensor (not shown) based on the current value I [A] flowing through the power storage device 3 input from the power storage device controller 13 according to the following formula (1).
SOC = ∫ (I / 3600) · dt / CAP × 100 (1)
Thus, the charge state SOC of the power storage device 3 is detected by integration. Here, the state of charge SOC [%] indicates the state of charge of the power storage device 3, and CAP [Ah] indicates the total capacity of the power storage device 3. In addition, since an error occurs in the current value detected by the current sensor, the accuracy of the calculated charging state SOC is improved by appropriately correcting the charging state SOC obtained by a method other than integrating the current values. it can.

  Subsequently, in step S2, regenerative energy obtained when regenerative braking is performed by the drive motor 4 from the vehicle running state is predicted. Specifically, as shown in the subroutine of FIG. 3, in this process, first, in step S21, the current vehicle speed VSP [km / h] is read from the vehicle speed signal from the vehicle speed sensor 15, and in step S22, the current A vehicle speed pattern is predicted when it is assumed that regenerative braking is performed by the drive motor 4 from the vehicle state. The vehicle speed pattern is obtained by, for example, setting a target regenerative braking torque generated by the drive motor 4 for each vehicle speed in advance, so that the vehicle speed VSPt [km / h] at a certain time t [sec] during deceleration is expressed by the following formula (2 )

から求めることができ、上記式（２）の演算を回生制動開始から車両停止に至るまで繰り返すことにより、減速時の車速パターンを得ることができる。ここで、ＶＳＰ_t-1［ｋｍ／ｈ］はある時間ｔの１秒前における車速、ｇ［ｍ／ｓ²］は重力加速度、ｉは総ギア比、η［％］は動力伝達効率、ｒ_D［ｍ］はタイヤ有効半径、μ_r［ｋＮ］は転がり抵抗、ｍ_veh［ｋｇ］は車両総重量、μ₁［ｋＮ・ｈ²／ｍ²・ｋｍ²］は空気抵抗係数、Ａ［ｍ²］は前面投影面積、φは車両回転部を考慮した場合の見かけの重量増加分(車両内の回転部分慣性重量を車両総重量割り算し得られる)である。また、ｔＴｍ［Ｎｍ］は目標回生制動トルクであり、例えば、各車速において一定減速度を得られるように目標回生制動トルクを設定しても良いし、また、内燃機関１のみを駆動源とする車両で発生するエンジンブレーキ相当の制動力が得られるように設定してもよい。さらに、ＧＲＤは道路勾配を示し、例えば、ナビゲーション手段１７の地図情報から値を取得する。

The vehicle speed pattern at the time of deceleration can be obtained by repeating the calculation of the above formula (2) from the start of regenerative braking to the stop of the vehicle. Here, VSP _t-1 [km / h] is the vehicle speed 1 second before a certain time t, g [m / s ² ] is the gravitational acceleration, i is the total gear ratio, η [%] is the power transmission efficiency, r _D [m] is the effective tire radius, μ _r [kN] is the rolling resistance, m _veh [kg] is the total weight of the vehicle, μ ₁ [kN · h ² / m ² · km ² ] is the air resistance coefficient, and A [m ² ] is a front projection area, and φ is an apparent weight increase when the vehicle rotating part is taken into consideration (obtained by dividing the rotating part inertia weight in the vehicle by the total vehicle weight). Further, tTm [Nm] is a target regenerative braking torque. For example, the target regenerative braking torque may be set so as to obtain a constant deceleration at each vehicle speed, or only the internal combustion engine 1 is used as a drive source. You may set so that the braking force equivalent to the engine brake generated in a vehicle may be obtained. Further, GRD indicates a road gradient, and a value is acquired from map information of the navigation means 17, for example.

In the regenerative energy prediction in step S23, the regenerative power Prg [kW] at the time of regenerative braking can be obtained by integrating from the start of braking until the vehicle stops. That is, the vehicle speed VSPt [km] and the rotational speed Nm [rpm] of the drive motor 4 are expressed by the following equation (3).
Nm = VSPt × (1000 / 2π · rD) × (i / 60) (3)
Since there is a relationship, the regenerative power Prg [kW] at time t [sec] is expressed by the following equation (4).
Prg = (tTm · Nm · 2π) / (60 · 1000) (4)
It can be calculated from Since loss occurs when the drive motor 4 operates, the prediction accuracy of regenerative power at time t [sec] is improved by subtracting the loss from the regenerative power Prg [kW] obtained by the above equation (4). be able to. FIG. 7 shows the efficiency characteristics of the drive motor 4. The characteristics are mapped in advance and stored in a memory, and the operating point of the drive motor 4 is searched to obtain the efficiency at that time. Electric power can be obtained. In the isoefficiency line, the highest efficiency is indicated by ηm _max .

  Next, the regenerative energy Erg [kJ] obtained from when the drive motor 4 starts braking until the vehicle stops is expressed by the following equation (5).

から求める。ここで、Ｔ_start［ｓｅｃ］は回生開始時間、Ｔ_end［ｓｅｃ］は予想した回生終了時間である。以上のステップＳ２１〜Ｓ２３により、その走行状態における回生エネルギーを予測することができる。

Ask from. Here, T _start [sec] is the regeneration start time, and T _end [sec] is the expected regeneration end time. By the above steps S21 to S23, the regenerative energy in the traveling state can be predicted.

  In step S <b> 3, it is determined whether or not the regenerative energy predicted in step S <b> 2 can be charged within the range of the upper limit SOC set in consideration of prevention of overcharge of the power storage device 3. In this process, the state of charge SOC required for charging the power storage device 3 with the regenerative energy predicted in step S2 = recovery ensuring SOCRG is obtained, and the determination is made in comparison with the current state of charge SOC detected in step S1. Specifically, the determination is made according to the procedure shown in FIG. In addition, in the procedure shown in FIG. 4, the procedure which suppresses the frequent fluctuation | variation of the operating point of the electric power generating apparatus 7 accompanying the change before and behind regeneration ensuring SOCRG of the charge condition SOC of the electrical storage apparatus 3 is added.

That is, in step S31, regeneration secured SOCrg [%], which is the SOC to be secured for receiving the regenerative energy Erg in the power storage device 3, is obtained. The regeneration secured SOCRG [%] is expressed by the following formula (6).
SOCrg = SOCup− (Erg × 100 × 1000) / (CAP × Vave)
... (6)
Can be obtained from Here, SOCup is the upper limit SOC of power storage device 3, and Vave is the average voltage of power storage device 3.

  In step S32, it is determined whether or not the previous regenerative charge availability determination is possible. If yes, the process proceeds to step S33, and if not, the process proceeds to step S36. If it is possible to determine whether or not the previous regenerative charge is possible, in step S33, the charge state SOC [%] is compared with the regeneration secured SOCrg [%], and the charge state SOC [%] is smaller. In step S34, it is determined whether or not regenerative charging is possible. If the state of charge SOC is larger in step S33, the process proceeds to step S35, and the regenerative charge availability determination is denied.

  If the previous regenerative chargeability determination in step S32 is negative, in step S36, the state of charge SOC [%] is compared with the value obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCRG. Then, the charged state SOC [%] is compared with the value obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCrg [%]. If the charged state SOC [%] is smaller, the process proceeds to step S37. Therefore, the regenerative chargeability determination is permitted. If the state of charge SOC is larger in step S36, the process proceeds to step S38, and the regenerative charge availability determination is denied. Here, the predetermined SOCmrg [%] is provided in order to prevent the operating point of the power generation apparatus 7 from fluctuating frequently and causing the driver to feel uncomfortable with frequent switching of the availability determination. It plays a role. This value may be adapted so as not to give a sense of incongruity by experiment.

  FIG. 8 shows the relationship between the state of charge SOC [%] and the regenerative securing SOCrg [%] in steps S35 and S38. In this case, the state of SOCa in the figure in which the expected regenerative energy cannot be sufficiently charged (step S35). Alternatively, although the regenerative energy can be sufficiently charged, the state of the SOCb in the figure that is determined to be unchargeable by the hysteresis (SOCmrg) for determining whether or not the regenerative energy is considered in consideration of the influence on the drivability in step S36 (step S38) ).

  In step S4, the target power generation efficiency when operating the power generation device 7 is set according to the result of the regenerative charge availability determination in step S3. Here, first, the power generation efficiency will be described.

  In the series hybrid vehicle composed of the electric power generated by the generator 2 or the electric power stored in the power storage device 3 and further the drive motor 4 driven by both of them, the power generation device 7 and the drive as the drive device Since the output shaft of the motor 4 is not mechanically connected, the operating point of the power generator 7 can be freely selected without being influenced by the traveling state. In order to improve fuel consumption, it is preferable to drive at an operating point at which the fuel consumption is minimized when an output is taken. This operating point can be obtained based on the fuel consumption rate characteristic of the internal combustion engine 1 shown in FIG. 9 and the efficiency characteristic of the generator 2 shown in FIG. FIG. 10 shows an example of the operating point of the internal combustion engine 1 when the output to be extracted is increased, and the internal combustion engine 1 realizes the operating point according to a target value of generated power to be described later. The engine 1 and the generator 2 are controlled.

The power generation efficiency [cc / kJ] is calculated from the following equation (7) from the output [kW] that can be taken out when the power generation device 7 is operated and the amount of fuel [cc / sec] consumed when the output is obtained.
Power generation efficiency = (fuel consumption) / (output that can be taken out from the power generation device) (7)
Can be defined as The smaller the value of the power generation efficiency, the higher the output with a small amount of fuel, and the higher the efficiency.

  Further, if the generated power is larger than the power consumed by the drive motor 4 for realizing the driving force required by the driver or the power consumed by the auxiliary machine, the difference (excess) power is charged to the power storage device 3. A loss is generated at the time of discharging, and a loss is also generated when discharging from the power storage device 3 in the future. Therefore, when the power generation efficiency is defined in consideration of how much generated power can be taken out when the power storage device 3 is charged and discharged in the future, the efficiency can be defined as the effective fuel consumption rate. FIG. 11 shows the characteristics of the effective fuel consumption rate when the generated power is increased when there is a predetermined power consumption. When the power consumption is small, the overall efficiency is poor. Similarly, when the power is 30 [kW], the point of generating 30 [kW] is the highest efficiency, and it can be seen that the efficiency decreases as the power consumption increases.

  In the present embodiment, the description will be made assuming that the effective fuel consumption rate is equal to the power generation efficiency, but a certain effect can be obtained even if it is defined as the above equation (7).

  The specific process in step S4 is executed by a subroutine shown in FIG. In the subroutine shown in FIG. 5, in step S41, it is determined whether or not the regenerative charge availability determination in step S3 is possible. If yes, the first power generation efficiency is set as the target power generation efficiency in step S42. To do. If it is determined in step S41 that regenerative charging is not possible, the process proceeds to step S43, and in step S43, the second power generation efficiency that is higher than the first power generation efficiency is set as the target power generation efficiency.

  Here, the first power generation efficiency is calculated based on the following idea. FIG. 12 shows the amount of charge to the power storage device 3 when the power generation device 7 is operated at an operating point that satisfies the power generation efficiency. It can be seen that the charge amount tends to increase as the power generation efficiency decreases. This tendency applies to both the power generation device 7 constituted by the internal combustion engine 1 and the generator 2 and the power generation device 7 constituted by a fuel cell.

  FIG. 13 explains the first power generation efficiency. The first power generation efficiency is calculated based on the tendency of FIG. 12. If the SOC is low by associating the state of charge SOC with the target power generation efficiency, FIG. The target power generation efficiency is set low so that the amount of charge is increased even if the efficiency is low. Conversely, if the SOC is high, priority is given to discharging, and charging is performed only when the efficiency is high. The target power generation efficiency is set according to the need for charging. Although the relationship between the SOC and the target power generation efficiency is linear in FIG. 13, the relationship between the SOC and the target power generation efficiency may be characterized so that the fuel consumption during traveling can be effectively reduced based on the above tendency.

  FIG. 14 shows the relationship between the state of charge SOC [%] and the regeneration secured SOCrg [%] in step S42, the regenerative energy can be charged, and the vehicle travels with the target power generation efficiency corresponding to the SOC. This is a state in which an effect of improving fuel efficiency can be obtained.

  The second power generation efficiency only needs to be higher than that of the first power generation efficiency, but is set when the regenerative charge availability determination in step S41 is negative, for example, As shown in FIG. 6, in the first step S431, when it is possible to determine whether or not the previous regenerative charge is possible, in step S432, the previous first power generation efficiency is set as the second power generation efficiency. At least the first power generation efficiency (= second power generation efficiency) of the previous time may be sufficient for the first power generation efficiency that decreases in conjunction with the decrease of the SOC in the charge / discharge control in step S6. .

  Step S5 calculates target generated power that satisfies the first power generation efficiency or the second power generation efficiency set as the target power generation efficiency (≈effective fuel consumption rate). That is, in the characteristic of the effective fuel consumption rate shown in FIG. 15 (= FIG. 11), target generated power that achieves target power generation efficiency≈effective fuel consumption rate is calculated. FIG. 15 shows a case where the power consumption is 20 [kW], and when the target power generation efficiency (≈effective fuel consumption rate) indicated by the broken line is set, the power generation indicated by ▲ is calculated as the target value.

  In step S6, the internal combustion engine 1 and the generator 2 are controlled to realize the target generated power obtained in step S5, and the drive motor 4 is controlled so as to satisfy the driver's required driving force. Here, the operating points of the internal combustion engine 1 and the generator 2 are controlled so as to realize the rotational speed and torque of the internal combustion engine corresponding to the target generated power in FIG.

  Here, when the first power generation efficiency is set as the target power generation efficiency, that is, by comparing the state of charge SOC [%] with the value obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCRG [%]. When it is determined that the SOC [%] is smaller or equal (step S34 or S37), the target power generation efficiency is changed according to the state of charge SOC [%], and consumed by the drive motor or auxiliary equipment. The target generated power corresponding to the consumed power is generated to suppress charging / discharging of the power storage device 3, and the regenerative energy generated by the drive motor 4 is charged to the power storage device 3 during regeneration.

  In addition, when the second power generation efficiency is set as the target power generation efficiency, that is, in the state of charge SOC [%], the regeneration secured SOCrg [%] and the value obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCrg If it is determined that it is large (step S35 or S38), a discharging operation is performed to lower the state of charge SOC [%] until the determination condition of step S36 is satisfied.

  The discharging operation here is a power that is smaller than the power consumed by the drive motor 4 and the auxiliary machine, that is, the target generated power based on the second power generation efficiency, and the internal combustion engine 1 and the generator 2 are set so as to realize the generated power. Control. Further, as the target generated power, a value that is smaller than the consumed power by a predetermined power is set, or depending on the difference between the charged state SOC [%] and the value obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCRG The discharge operation may be enabled by setting so that the larger the value is, the smaller the generated power is with respect to the power consumption.

  FIG. 16 shows an image of the process when the second power generation efficiency is set in step S432. When the regeneration reservation SOCRG [%] cannot be secured in the SOC indicated by the point a, the discharge operation is performed. During the operation, the engine is operated at the same target power generation efficiency as the point a which is the previous first power generation efficiency. Then, the operation at the target power generation efficiency similar to that at point a is continued until reaching point b where the SOC value is obtained by subtracting the predetermined SOCmrg [%] from the regeneration secured SOCRG, that is, until charging of regenerative energy is started.

  In the above-described embodiment as the second power generation efficiency, the first power generation efficiency immediately before the determination result of the regenerative charge availability determination changes from acceptable to unacceptable is set. However, the second power generation efficiency is higher than the first power generation efficiency. For example, it can be set as shown in FIG.

  That is, the power generation efficiency at which the highest power generation possible with the current power consumption can be set as the second power generation efficiency (step S433). This is because, as indicated by a circle in FIG. 18, the most efficient power generation efficiency that can be taken for each power consumption is set as the second power generation efficiency, so that the fuel during discharge traveling can be further increased. The consumption rate can be effectively reduced.

  Further, as the second power generation efficiency, as shown in FIG. 19, a point c having the highest power generation efficiency among all the power consumption may be set. It is the power consumption (35 [kW]) shown at point c in FIG. 14 and is the most efficient point among the lines showing the efficiency when power equal to the power consumption shown by the thick line is generated. Then, it is referred to as predetermined power consumption (highly efficient power generation power). The discharge operation is first made different depending on whether the power consumption (driving / auxiliary power) is larger than the predetermined power consumption (highly efficient power generation power).

  That is, when it is determined that the power consumption (driving / auxiliary power factor) is larger than the predetermined power consumption (high efficiency power generation power), the power generation at this point c is the highest efficiency. In addition, it is possible to cause the discharge to be performed with high efficiency by discharging from the power storage device 3 an amount that is insufficient for the power consumption.

  On the other hand, when it is determined that the power consumption is smaller than or equal to the predetermined power consumption, the state of charge SOC and the regeneration secured SOCRG are compared with the power generation efficiency when power equal to the current power consumption is generated. Depending on the difference, the power generation efficiency is deteriorated and the generated power is reduced to discharge. That is, if the difference between the state of charge SOC [%] and the regeneration-retained SOCRG [%] is large, the regenerative charge cannot be sufficiently charged unless the battery is quickly discharged and the state of charge is less than the regeneration-retained SOCRG. For this reason, discharge power is increased by reducing the generated power by setting the power generation power to a small value according to the difference, that is, the amount of discharge energy. By doing so, it is possible to minimize the deterioration of the power generation efficiency.

  In the embodiment described above, the power generation device 7 has been described as being constituted by the internal combustion engine 1 and the generator 2. However, as shown in FIG. 20, the fuel cell 8 constitutes the power generation device. Is applicable.

  In the system configuration of the hybrid vehicle shown in FIG. 20, the drive motor 4 is driven by the power generated by the fuel cell 8, the power stored in the power storage device 3, or the power supplied from both. . In the fuel cell 8, the generated power is controlled by the fuel cell controller 18 based on the target generated power command value output from the integrated controller 10. As the fuel cell 8, a polymer electrolyte fuel cell is optimal for a moving body such as a hybrid vehicle. Further, the hydrogen gas that is the fuel gas may be stored in a hydrogen cylinder, or may be generated by reforming a raw material such as alcohol using a reformer. It is also possible to apply various types of fuel cells such as phosphoric acid type and molten carbonate type.

  Even in such a hybrid vehicle, when it is determined that the regenerative energy predicted by the regenerative energy amount predicting unit that predicts the regenerative energy amount obtained during vehicle braking based on the traveling state of the vehicle cannot be charged in the power storage device 3. The second power generation efficiency that is at least high with respect to the first power generation efficiency can be set as the target power generation efficiency to control the power generated by the fuel cell 8. That is, when the predicted regenerative energy cannot be sufficiently charged in the power storage device 3, priority is given to discharging until a state where the predicted regenerative energy can be charged is reached, and at least the first time until it is determined that charging is possible again. Since the second power generation efficiency which is higher than the power generation efficiency of 1 is set, the fuel consumption during traveling can be reduced as compared with the conventional power generation efficiency.

  In the above embodiment, the hybrid vehicle is described as applied to a series hybrid vehicle in which the power generation device 7, the power storage device 3, and the drive motor 4 are connected in series. However, although not illustrated, for example, a continuously variable transmission It can also be applied to a stepped transmission or a parallel hybrid vehicle using a planetary gear mechanism. A method of satisfying the target power generation efficiency by the parallel hybrid vehicle is well known, for example, as described in Japanese Patent Application Laid-Open No. 2002-171604, and is omitted, but the internal combustion engine operating point and speed change satisfying the power generation efficiency determined by this control are omitted. The machine speed ratio and the motor operating point may be set.

  In the present embodiment, the following effects can be achieved.

  (A) The drive motor 4 for driving the vehicle, the power generation device 7, the electric power generated by the power generation device 7 and the regenerative power generated by the drive motor 4 when the vehicle is decelerated are stored, and the drive motor 4 as required. And a power storage device 3 for supplying electric power to the vehicle. A charge state detection means (step S1) for detecting a charge state of the power storage device 3 and a vehicle state based on the vehicle travel state. The regenerative energy amount predicted based on the regenerative energy amount predicting means (step S2) for predicting the regenerative energy amount to be generated, the charge state of the power storage device 3 and the regenerative energy amount predicted by the regenerative energy amount predicting means. The regenerative energy amount predicted by the regenerative charge availability determination means (step S3) for determining whether or not the regenerative charge is possible is determined by the regenerative charge availability determination means. If it is determined that electricity can be generated, the first power generation efficiency corresponding to the state of charge of the power storage device 3 is set as the target power generation efficiency of the power generation device 7, and it is determined that the predicted amount of regenerative energy cannot be charged. In this case, the second power generation efficiency that is higher than the first power generation efficiency is set as the target power generation efficiency of the power generator 7 until it is determined that the regenerative energy can be charged again. Efficiency setting means (step S4) and charge / discharge control means (step S6) for controlling the drive motor 4 and the power generation device 7 so as to realize the target power generation efficiency set by the target power generation efficiency setting means. For this reason, when the predicted regenerative energy cannot be charged sufficiently, it is possible to suppress an increase in power generation / charge amount when lowering the SOC of the power storage device 3 to secure the regenerative energy, and to reduce the fuel consumption until the start of regenerative energy charging. It can be reduced.

  (A) When the most efficient value obtained by operating the power generation device 7 in the current traveling state is set as the second power generation efficiency, the effect (a) of the fuel consumption reduction effect is achieved. Can be improved.

  (C) Regenerative charge availability determination means (step S3), when the predicted regenerative energy reaches a state of charge SOC that is lower by a predetermined value (SOCmrg) than the state of charge SOC in which the predicted regenerative energy can be charged. If it is determined that it is possible, hysteresis is provided in the state of charge used for determining whether or not regenerative charging is possible, and the power generation device 7 is configured so that the target power generation efficiency is frequently switched between the first power generation efficiency and the second power generation efficiency. The change of the operating point can be suppressed, and the uncomfortable feeling due to the frequent change of the operating point of the power generator 7 can be reduced.

  (D) When the second power generation efficiency is set as the target power generation efficiency by the target power generation efficiency setting means (step S4), when the power storage device 3 is charged, the predicted regenerative energy can be charged. Driving for calculating the driving / auxiliary power, which is the sum of the driving power and the power consumption of the auxiliary equipment, in order to realize the required driving power of the driver The driving / auxiliary required work power is calculated from auxiliary machine power calculation means and high-efficiency power generation power calculation means for calculating the highest power generation efficiency among the power generation efficiencies that can be obtained by the power generation device 7. Is smaller than the high-efficiency power generation power, the power generation power is set to a value smaller than the driving / auxiliary power power as the difference between the charge state and the charge state capable of charging the predicted regenerative energy is larger, The drive When the required machine power is higher than the high-efficiency power generation power, the power generated by the power generation device 7 is set as the high-efficiency power generation power, and the power storage device supplies insufficient power with respect to the required drive / auxiliary power It was made to supply from 3. For this reason, when the driving / auxiliary power rate is smaller than the high-efficiency power generation rate, the deterioration in power generation efficiency is minimized according to the amount of energy discharged until the regenerative energy can be charged. When the power generation power to be limited is selected and the driving / auxiliary power power ratio is larger than the high efficiency power generation power, the regenerative energy can be charged while performing high efficiency operation. can do.

  (E) As the first power generation efficiency, when the target power generation efficiency is set to be higher as the charging state of the power storage device 3 is higher, it is possible to set the target power generation efficiency in accordance with the necessary degree of charging. Specifically, if the SOC is low, the target power generation efficiency is set low and the power generation / charge amount is increased even if the efficiency is low. Conversely, if the SOC is high, the power storage device 3 moves to the drive motor 4. It is possible to avoid unnecessary power generation / charging by increasing the chances of supplying electric power and traveling, setting the target power generation efficiency high and performing power generation / charging only when the efficiency is high.

  (F) Even if the power generation device 7 is constituted by the internal combustion engine 1 and the generator 2 or the fuel cell 8, the effects (a) to (e) can be achieved.

The system block diagram of the series hybrid vehicle as a control apparatus of the hybrid vehicle which shows one Embodiment of this invention. The flowchart which similarly showed the content of the process by an integrated controller. The flowchart of the subroutine which showed the content of the process of regenerative energy prediction. The flowchart of the subroutine which showed the content of the process of regenerative charge availability determination. The flowchart of the subroutine which showed the content of the process of target electric power generation efficiency setting. The flowchart of the subroutine which showed the content of the process of 2nd power generation efficiency calculation. The characteristic view which shows the efficiency characteristic of a drive motor and a generator. Explanatory drawing which shows the relationship between charge condition SOC of an electrical storage apparatus, and regeneration ensuring SOC. The characteristic view which shows the fuel consumption rate characteristic of an internal combustion engine. The characteristic view which shows the operating point of an internal combustion engine. The characteristic view which shows the characteristic of the effective fuel consumption rate at the time of increasing generated electric power when there exists predetermined power consumption. The characteristic view which shows the charge amount to the electrical storage apparatus at the time of drive | operating a power generator at the operating point which satisfy | fills power generation efficiency. The characteristic view which shows the relationship between SOC of a electrical storage apparatus, and 1st electric power generation efficiency. Explanatory drawing which shows the relationship between charge condition SOC of an electrical storage apparatus, and regeneration ensuring SOC. The characteristic view explaining the calculation method of target electric power generation. Explanatory drawing which shows the relationship between charge condition SOC of the electrical storage apparatus and regeneration ensuring SOC explaining 2nd electric power generation efficiency. The flowchart of the subroutine explaining the procedure of another calculation method of 2nd power generation efficiency. The characteristic view explaining the 2nd power generation efficiency shown in FIG. The characteristic view explaining another 2nd power generation efficiency. The system block diagram of a series hybrid vehicle provided with a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Generator 3 Power storage device 4 Drive motor 5 Final drive device 6 Drive wheel 7 Power generation device 8 Fuel cell

Claims (7)

A drive motor for driving the vehicle, a power generation device, a power storage device that stores power generated by the power generation device and regenerative power generated by the drive motor when the vehicle decelerates, and supplies power to the drive motor as needed A hybrid vehicle control device comprising:
Charging state detecting means for detecting a charging state of the power storage device;
Regenerative energy amount prediction means for predicting the regenerative energy amount obtained during vehicle braking based on the running state of the vehicle;
Based on the state of charge of the power storage device and the amount of regenerative energy predicted by the amount of regenerative energy predicting means, regenerative charge availability determination means for determining whether or not the predicted amount of regenerative energy can be charged;
When it is determined that the amount of regenerative energy predicted by the regenerative charge availability determination unit is chargeable, a first power generation efficiency corresponding to the state of charge of the power storage device is set as a target power generation efficiency of the power generation device, and the prediction If it is determined that the regenerated energy amount cannot be charged, the second power generation efficiency which is high with respect to the first power generation efficiency is used until the regenerative energy is determined to be rechargeable again. Target power generation efficiency setting means for setting as the target power generation efficiency of the device;
A hybrid vehicle control apparatus comprising: a drive motor; and a charge / discharge control means for controlling the power generation apparatus so as to realize the target power generation efficiency set by the target power generation efficiency setting means.   2. The hybrid vehicle control device according to claim 1, wherein the second power generation efficiency is set to a most efficient value obtained by operating the power generation device in a current traveling state.   The regenerative charge availability determination unit determines that the predicted regenerative energy can be charged when the battery reaches a charge state that is lower by a predetermined value than the charge state in which the predicted regenerative energy can be charged. The hybrid vehicle control device according to claim 1. The charge / discharge control means can charge the predicted regenerative energy when the second power generation efficiency is set as the target power generation efficiency by the target power generation efficiency setting means and the power storage device is charged. Discharging means for discharging to a charged state,
The discharging means is a driving / auxiliary power calculation means for calculating a driving / auxiliary power that is the sum of the driving power and power consumption in the accessories to realize the required driving force of the driver; When the drive / auxiliary required power is smaller than the high-efficiency power generation power from the high-efficiency power generation power calculation means for calculating the power generation power that is the highest power generation efficiency that can be obtained by the power generation device The power generation power is set to a value smaller than the driving / auxiliary power ratio as the difference between the charging state and the charging state enabling the predicted regenerative energy to be charged, and the required driving / auxiliary power ratio is higher. When the power generation efficiency is higher than the power generation efficiency, the power generation apparatus generates a high power generation power, and the power storage device supplies insufficient power to the drive / auxiliary power requirements. Any one of claims 1 to 3 Control apparatus for a hybrid vehicle according to One.   The hybrid vehicle control device according to any one of claims 1 to 4, wherein the first power generation efficiency sets a higher target power generation efficiency as the state of charge of the power storage device becomes higher. .   6. The hybrid vehicle control device according to claim 1, wherein the power generation device includes an internal combustion engine and a generator.   6. The control apparatus for a hybrid vehicle according to claim 1, wherein the power generation apparatus is configured by a fuel cell.

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