JP5501072B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a drive control device for a hybrid vehicle that includes an engine and an electric motor as a power source, and can charge an electric storage device by rotating the electric motor as a generator.

In recent years, hybrid vehicles equipped with an engine and an electric motor as power sources and capable of switching the power source according to the situation have been developed as solutions for improving fuel consumption and reducing CO ₂ emissions. In a hybrid vehicle, the engine is operated with a power larger than that required for traveling, the engine is controlled to operate in an efficient region, and the electric motor is rotated with the surplus power to charge the power storage device. Yes. The electric power stored in the power storage device is used to drive the electric motor, and the electric motor is used as a power source instead of the engine to improve fuel consumption and reduce CO ₂ emissions. However, even if the electric motor is used as a power source, the electric power is supplied to the electric motor from the power storage device, and the power storage device is charged by operating the engine. For this reason, the electric motor also consumes fuel indirectly, and if the charging is continued for a long time in a region where the engine combustion efficiency is poor, the fuel consumption is deteriorated. Therefore, in Patent Document 1, the target SOC at the time of charging is set according to the efficiency of the engine, the target SOC is set lower in the inefficient state to reduce the charge amount, and the target SOC is set higher when the efficiency is high. Controls that charge a lot have been proposed.

  In addition, since the hybrid vehicle includes two power sources, that is, an engine and an electric motor, the power source can be arbitrarily selected. Therefore, in order to improve fuel consumption, it is necessary to select a more efficient power source according to the traveling state. In Patent Document 2, the amount of fuel consumed is calculated as an energy cost (g / kWh), the energy cost when traveling with an electric motor calculated including the amount of fuel consumed for charging the power storage device, and the engine traveled The control which improves a fuel consumption by comparing the energy cost at the time and selecting the power source with few energy costs is disclosed.

  However, in the technique of Patent Document 1, the target SOC is determined based only on engine efficiency. The power storage device is charged by rotating the electric motor with the engine, but the operating range where the engine efficiency is good is not necessarily the efficient operating range of the electric motor. Therefore, even if the target SOC is set high because the engine efficiency is good, if the power generation efficiency of the motor is not good, it will be charged a lot in a state where the efficiency is not good as a whole, and the effect of improving fuel consumption will be reduced there is a possibility. Moreover, the thing of patent document 2 is calculating the energy cost at the time of charge, when charging an electrical storage apparatus. However, in the power storage device, electric power charged at different energy costs in the past is mixed, and the technique described in Patent Document 2 is now used when actually using the power stored in the power storage device. There is no mention of a means of identifying how much energy cost the power is charged in the past.

  Further, in Patent Documents 1 and 2, the fuel efficiency of the hybrid vehicle at the time of charging / discharging is not sufficient.

JP 2008-109740 A Japanese Patent Laid-Open No. 11-229916

  The objective of this invention is providing the control apparatus which improves the fuel consumption of a hybrid vehicle.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-mentioned problems. To give an example, an engine that operates by burning fuel and an electric motor that operates with electric power stored in a power storage device are provided as a drive source. In the hybrid vehicle capable of charging the power storage device by rotating the electric motor as a generator in the engine, the target storage amount of the power storage device is based on the stored power efficiency of charging the power storage device. After determining and charging the power storage device to the power storage target value, when shifting to running by the electric motor, whether or not to continue running by the electric motor is compared with the total power running efficiency and the combustion efficiency of the engine and determined, the stored power efficiency, and combustion efficiency of the engine at the time of charging, the determined based on the power generation efficiency of the motor, determined the stored power The rate, and classified by a few percent is divided into good order of efficiency by storing the electric power stored storage means, the overall power running efficiency, Ru is determined based on the stored power generation efficiency of the electric storage power efficiency and the electric motor It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle control apparatus which improved the fuel consumption can be provided.

The block diagram which shows the outline of a structure of the vehicle control apparatus in this embodiment. The flowchart explaining the target SOC determination system in this embodiment. The flowchart explaining the driving force source selection system in this embodiment. The figure explaining the storage method of stored electric power efficiency. The figure of a target electric power generation torque calculation table. The figure of an engine combustion efficiency map. The figure of an electric motor power running efficiency map. The figure of an electric motor charging efficiency map. The figure of a target SOC calculation table.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram schematically showing the outline of the vehicle control system of the present invention.

  The engine 2 is connected to an electric motor 4 via a clutch 3. By controlling the on / off state of the clutch 3, it is possible to switch the running state such as running by the engine 2, running by the electric motor 4, and generating electric power by the electric motor 4 while running by the engine 2.

  The power conversion means 5 is constituted by, for example, a rectifier, converts DC power from the power storage device 7 into three-phase AC power, and supplies it to the motor 4. The electric motor 4 operates as an electric motor by receiving a current supplied to a stator winding (not shown).

  Further, when the electric motor 4 is rotated by the rotational driving force of the engine 2, an electromotive force is induced in a stator winding (not shown) in the electric motor 4 to generate three-phase AC power, and the power exchanging means 5. It operates as a generator that supplies electric power to the power storage device 7 via.

  Further, even when the engine 2 is stopped during deceleration or downhill, the electric motor 4 receives the rotational force from the tire 9, so that an electromotive force is generated in a stator winding (not shown) in the electric motor 4. Induced, it generates three-phase AC power and operates as a generator that supplies power to the power storage device 7 via the power exchange means 5.

  The rotational speed of the engine 2 and the rotational speed of the electric motor 4 are detected by the engine rotational speed detecting means 14 and the electric motor rotational speed detecting means 16, respectively, and sent to the vehicle control device 1 through a communication means 19 such as CAN (Control Area Network). It is done. Further, the torque of the engine 2 and the torque of the electric motor 4 are calculated by the engine torque estimating means 15 and the electric motor torque estimating means 17, respectively, and sent to the vehicle control device 1 through the communication means 19 such as CAN. The vehicle control apparatus 1 determines the combustion efficiency of the engine 2, the power running of the motor 4, and the power generation efficiency based on the rotational speed and torque information sent through the communication means 19, and the engine combustion efficiency calculation means 10 and the motor power running power generation efficiency calculation means, respectively. 11 is used.

  The stored power efficiency calculation means 12 calculates the stored power efficiency based on the engine combustion efficiency of the engine 2 and the power generation efficiency of the motor 4 when charging the power storage device 7. The storage power efficiency storage means 13 compares the SOC information sent from the SOC estimation means 18 of the power storage device 7 through the communication means 19 such as CAN with the storage power efficiency calculated by the storage power efficiency calculation means 12, and It memorizes how much power is stored in the power storage device 7 with the power storage power efficiency of the level.

  The vehicle control device 1 obtains the total power running efficiency from the electric motor power running efficiency and the stored power efficiency corresponding to the current SOC, compares it with the engine combustion efficiency, and selects the more efficient one as the vehicle driving power source. .

  Next, a method of setting the target SOC when charging the power storage device 7 will be described using the flowchart of FIG.

  First, at step 101, the engine speed detecting means detects the engine speed. Next, based on the rotational speed of the engine 2 detected in step 102, a target torque (tTe) of the engine 2 necessary for achieving the target engine combustion efficiency is calculated. The target torque (tTe) of the engine 2 is calculated by, for example, a table search as shown in FIG.

After the target torque (tTe) of the engine 2 is determined, a power generation torque command value (GenTm) of the motor 4 is determined in step 103. The power generation torque command value (GenTm) of the electric motor 4 is determined by obtaining the difference between the target torque (tTe) of the engine 2 and the torque (Te) of the engine 2 required for driving. By setting a value larger than the torque (Te) required for driving to the target torque (tTe) of the engine 2, the surplus torque can be used as torque for driving the electric motor 4 as a generator. Furthermore, the operating point of the engine 2 itself can be moved to the high torque side with high efficiency. The power generation torque command value (GenTm) of the electric motor 4 is
GenTm = tTe-Te
Can be obtained.

  Next, the process proceeds to step 104, where it is determined whether or not the power generation torque command value (GenTm) is equal to or smaller than the absolute value of the minimum torque (Tmmin) of the electric motor 4, and is equal to or smaller than the absolute value of the minimum torque (Tmmin). (YES in step 104), the process proceeds to step 105. And the target torque (tTm) of the generator 4 is set to GenTm.

  On the other hand, if the power generation torque command value (GenTm) is greater than or equal to the absolute value of the minimum torque (Tmmin) of the motor 4 (NO in step 104), the process proceeds to step 106. And the target torque (tTm) of the generator 4 is set to Tmmin.

  After setting the target torque (tTm) of the generator 4, the rotational speed of the electric motor 4 is detected in step 107, and the process proceeds to step 108.

In Step 108, the engine combustion efficiency (EngEff) and the power generation efficiency (MotGenEff) of the electric motor 4 are multiplied to obtain a stored power efficiency (StoredEnergyEff) that indicates how much power is stored in the power storage device 7. The stored energy efficiency (StoredEnergyEff) is
StoredEnergyEff = EngEff × MotGenEff
Can be obtained.

  The engine combustion efficiency (EngEff) is obtained by using a map as shown in FIG. 6 using the engine speed detected by the engine speed detecting means 14 and the engine torque calculated by the engine torque estimating means 15 as inputs. Further, the power generation efficiency (MotGenEff) of the electric motor 4 is obtained using a map as shown in FIG. 7 using the rotation speed detected by the motor rotation speed detection means 16 and the motor torque calculated by the motor torque estimation means 17 as inputs. .

  Finally, the process proceeds to step 109, and the target SOC (TargetSOC) of the electric motor 4 is determined. The target SOC (TargetSOC) is obtained by using a table having the stored power efficiency (StoredEnergyEff) as an input. The target SOC (TargetSOC) is set low when the stored power efficiency (StoredEnergyEff) is low, and is set high when the stored power efficiency (StoredEnergyEff) is high. By doing so, the charging time in an inefficient state can be shortened, and at the same time, a large amount of high-quality electric power (electric power charged in an efficient state) can be stored in the power storage device 7.

  As a table setting method for determining the target SOC (TargetSOC), various methods can be considered. For example, the target SOC (TargetSOC) may be increased in proportion to the stored power efficiency (StoredEnergyEff) as shown in FIG. Further, the target SOC (TargetSOC) may be increased exponentially as shown in FIG. 9B with respect to the increase in stored power efficiency (StoredEnergyEff). Alternatively, when the stored power efficiency (StoredEnergyEff) changes within a certain range, the target SOC (TargetSOC) is not changed, and the target SOC (TargetSOC) is increased stepwise as shown in FIG. 9C. Also good.

  Next, a control method after the amount of power stored in power storage device 7 has reached the target SOC will be described using the flowchart of FIG.

  First, in step 201, it is determined whether or not the vehicle is decelerating. If the vehicle is decelerating (YES in step 201), the process proceeds to step 202.

  In step 202, it is determined whether or not the current SOC is lower than the SOC upper limit value (SOCmax). If it is lower (YES in step 202), regeneration is selected in step 210 and the process is terminated. If the current SOC is higher than the SOC upper limit value (SOCmax) (NO in step 202), the process proceeds to step 209, where braking is performed only with the friction brake, and the process is terminated.

  On the other hand, if the vehicle is not decelerating in step 201 (NO in step 201), the process proceeds to step 203 and the following processing is executed.

  In step 203, it is determined whether or not the current SOC is greater than the SOC lower limit value (SOCmin). If it is greater (YES in step 203), the process proceeds to step 204.

  On the other hand, when the current SOC is lower than the SOC lower limit value (SOCmin) (NO in step 203), the process proceeds to step 213, power generation is selected, and the process is terminated.

  In step 204, the engine combustion efficiency (EngEff) of the engine 2 is calculated. Since the calculation method is the same as that of step 108 in FIG. 1, detailed description thereof is omitted.

Proceeding to step 205, the total power running efficiency (TotMotEff) of the electric motor 4 is obtained. The total power running efficiency (TotMotEff) is obtained by multiplying the power storage efficiency (StoredEnergyEff) of the power storage device 7 and the power running efficiency (MotEff) of the electric motor 4. Total power running efficiency is
TotMotEff ＝ StoredEnergyEff × MotEff
Can be obtained.

  In step 206, it is determined whether the total power running efficiency (TotMotEff) is better than the engine combustion efficiency (EngEff). If the total power running efficiency (TotMotEff) is better (YES in step 206), the process proceeds to step 207.

  In step 207, it is determined whether or not the maximum torque (Tmmax) of the motor 4 exceeds the target drive torque (tTout). If it exceeds (YES in step 207), the process proceeds to step 211 to drive the motor 4 to the driving force. The EV traveling that travels as a source is selected, and the process ends.

  On the other hand, if the total power running efficiency (TotMotEff) of the electric motor 4 is lower than the engine combustion efficiency (EngEff) in step 206 (NO in step 206), or the maximum torque (Tmmax) of the electric motor 4 is the target drive torque in step 207. If it is below (tTout) (NO in step 207), the process proceeds to step 208.

  In step 208, it is determined whether or not the current SOC exceeds the target SOC (TargetSOC). If the current SOC is equal to or higher than the target SOC (TargetSOC) (YES in step 208), it is not necessary to generate power. Proceeding to 212, the engine running using the engine 2 as a driving force source is selected, and the process is terminated.

  On the other hand, if the current SOC is lower than the target SOC (TargetSOC) in step 208 (NO in step 206), the process proceeds to step 213, power generation is selected, and the process is terminated.

  Next, an example of a method for storing the stored power efficiency (StoredEnergyEff) will be described based on FIG.

  For example, as shown in FIG. 4, the electric power stored in the power storage device 7 is classified in order of efficiency by classifying the stored power efficiency (StoredEnergyEff) every several percent. By doing so, it is possible to easily grasp how much of the electric power stored in the power storage device 7 is charged with what efficiency.

By storing the stored power efficiency (StoredEnergyEff) by the method described above, the selection of the driving force source is determined, for example, by the method described below. As shown in FIG. 4A, when the value indicated by the SOC estimation means 18 of the power storage device is the value of SOC1, the stored power efficiency (StoredEnergyEff) is at least 70% or more. If the engine combustion efficiency (EngEff) is 25% and the motor power running efficiency (MotEff) is 85%, the total power running efficiency (TotMotEff) is
TotMotEff ＝ StoredEnergyEff × MotEff
Therefore, the electric motor 4 is selected as a driving force source because it is at least 59.5% or more and exceeds 25% of the engine combustion efficiency (EngEff).

  When the electric motor 4 is used as a driving force source and the value indicated by the SOC estimation means 18 of the power storage device decreases to the value of SOC2 shown in FIG. 4B, the power storage efficiency (StoredEnergyEff) is about 20%. It is. If the engine combustion efficiency (EngEff) is 25% and the motor power running efficiency (MotEff) is 85%, the total power running efficiency (TotMotEff) is 17%, which is lower than the engine combustion efficiency (EngEff) of 25%. Therefore, the vehicle control device 1 stops traveling by the electric motor 4 and shifts to a mode in which power is generated while traveling by the engine 2 or traveling by the engine 2.

  Therefore, the engine combustion efficiency (EngEff), the motor power running efficiency (MotEff), and the instantaneous power efficiency of each unit are not compared to select the driving power source, but until the fuel is actually converted to the driving power that moves the vehicle. Since the driving force source is selected in consideration of efficiency, the fuel consumption can be improved.

  Further, when running with the electric motor 4, the running with the electric motor 4 is not continued as much as possible until the electric power discharge lower limit (SOCmin) is reached, but the total power running efficiency (TotMotEff) and the engine combustion efficiency (EngEff) By comparison, it is determined whether or not to continue traveling by the electric motor 4. Therefore, even if the SOC of the power storage device 7 remains, it is possible to prevent the fuel consumption from deteriorating by continuing the traveling by the electric motor 4 using the power having a low power storage efficiency (StoredEnergyEff).

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the stored power efficiency (StoredEnergyEff) is obtained from the engine combustion efficiency (EngEff) and the motor power generation efficiency (MotEff), and the total power running efficiency (TotMotEff) is calculated from the stored power efficiency (StoredEnergyEff) and the motor. Although it calculates | requires from power running efficiency (MotEff), respectively, you may obtain | require including more parameters, for example, charging / discharging efficiency of the electrical storage apparatus 7, etc.

DESCRIPTION OF SYMBOLS 1 Vehicle control apparatus 2 Engine 3 Clutch 4 Electric motor 5 Electric power conversion means 6 Transmission 7 Electric power storage apparatus 8 Differential gear 9 Tire 10 Engine combustion efficiency calculation means 11 Electric motor power generation efficiency calculation means 12 Electric power generation efficiency calculation means 13 Electric power storage efficiency storage means 14 Engine speed detection means 15 Engine torque estimation means 16 Motor rotation speed detection means 17 Motor torque estimation means 18 SOC estimation means 19 Communication means 20 AC cable 21 DC cable

Claims (2)

An engine that operates by burning fuel and an electric motor that operates with electric power stored in the power storage device are provided as a drive source, and the electric power storage device is charged by rotating the motor as a generator in the engine. In a hybrid vehicle capable of
A power storage amount target value of the power storage device is determined based on power storage power efficiency for charging the power storage device, and after charging the power storage device to the power storage target value,
When shifting to running by the electric motor, whether to continue running by the electric motor drive is determined by comparing the total power running efficiency and the combustion efficiency of the engine,
The stored power efficiency is determined based on the combustion efficiency of the engine during charging and the power generation efficiency of the electric motor,
The determined stored power efficiency is classified every few percent, sorted in order of efficiency, and stored by stored power storage means,
The overall power running efficiency, the vehicle control apparatus characterized by the stored electric storage power efficiency Ru determined based on the power generation efficiency of the motor.   2. The vehicle control device according to claim 1, wherein after the amount of power stored in the power storage device reaches the power storage target value, charging of the power storage device is stopped, and the combustion efficiency of the engine is compared with the total power running efficiency. The vehicle control device is characterized in that either the traveling by the engine or the traveling by the electric motor is selected.

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