JP2008207570A - Control device of series hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a series hybrid vehicle adapted to obtain a stepped shift state and a continuous shift state, capable of improving drive feeling without giving a sense of discomfort to an occupant at the time of speed change in the stepped shift state. <P>SOLUTION: A speed change control line Z shown by a broken line, in which engine speed is changed at a stretch is set between a point "X" that is a current operating point of an engine and a target point "Y". The load torque of a generator is controlled so as to trace the speed change control line X. The generator and the engine are controlled so that the rotating speed of the engine is changed more quickly than when a high efficiency line L' is traced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

Conventionally, various hybrid vehicles that obtain the driving force of a vehicle with an engine and a motor have been proposed and are now in practical use.
Such hybrid vehicles are broadly divided into “parallel hybrid” that drives the vehicle by using or coordinating the engine and motor, and the engine exclusively drives the generator, and the vehicle is driven exclusively by the motor. There is a “series hybrid”.

  In the case of the series hybrid, the operating state of the engine can be controlled regardless of the driving state of the vehicle, and therefore there is an advantage that the engine can be always operated in the region where the fuel efficiency is highest.

  By the way, even for hybrid vehicles that emphasize fuel efficiency, there is a demand to improve drive feeling. Therefore, in the following Patent Document 1, on the premise of a parallel hybrid vehicle equipped with a transmission, there is provided a switching means for switching between a continuously variable transmission state and a stepped transmission state in response to a passenger's request, thereby eliminating the traveling state. There has been proposed a hybrid vehicle that can be switched between a step shifting state and a stepped shifting state.

Japanese Patent Laid-Open No. 2005-240891

  Of course, there is a demand for improving the drive feeling in the series hybrid vehicle, so the technical idea of Patent Document 1 described above is also applied to a series hybrid having no transmission, and a continuously variable transmission state and a stepped gear. It is conceivable that the speed change state can be obtained, and the stepless speed change state is switched to the stepped speed change state in accordance with a passenger's request or the like.

  However, in the case of the series hybrid, the vehicle is not directly driven by the engine, and therefore, when the gear is shifted in the stepped speed change state, the driving state of the vehicle changes greatly, but the operating state of the engine hardly changes. However, he felt uncomfortable and could make the drive feeling worse.

  Therefore, the present invention provides a control device for a series hybrid vehicle that is configured so as to obtain a stepped speed change state and a stepless speed change state, and without causing a passenger to feel uncomfortable when shifting in the stepped speed change state. An object of the present invention is to provide a control device for a series hybrid vehicle capable of improving the feeling.

  The control apparatus for a series hybrid vehicle according to the present invention includes an engine, a generator coupled to the output shaft of the engine, a battery that can be charged by at least power generation by the generator, and power generated from the generator or a battery. And a motor for driving the vehicle driven by the electric power of the series hybrid vehicle, wherein the stepless speed change mode for continuously changing the drive output of the motor and the drive output of the motor are stepwise changed. Shift mode control means for selectively setting the stepped shift mode under a predetermined condition, and engine control means for controlling the driving state of the engine based on a high efficiency control line set so that the engine efficiency is optimal. And when shifting in the stepped shift mode when the engine is driven, the engine is compared to the case based on the control line for high efficiency. The speed change control lines change rate of the rotation speed is set to be larger, in which a control line change means for changing a control line.

According to the above configuration, by providing the control line changing means for changing the control line for controlling the driving state of the engine to the shift control line for increasing the change speed of the engine rotational speed, When the engine speed changes, the engine speed changes abruptly along the shift control line.
For this reason, at the time of shifting in the stepped speed change mode, the occupant can recognize that the engine speed has changed rapidly and the operating state of the engine has changed significantly.

In one embodiment of the present invention, when the engine is controlled based on the shift control line changed by the control line changing means, the load torque of the generator is controlled to change the engine speed. The motor that supplies power so that the battery is charged / discharged and the driving force of the motor gradually changes as the amount of power generated by the generator changes during a shift. Control means are provided.
According to the above configuration, the load torque of the generator is controlled in order to increase the speed of change of the engine speed. By controlling this load torque, the power generation amount of the generator also varies greatly. It will be. The driving power generated by the motor gradually changes as the battery supplementally charges and discharges power (supplying and receiving power) in response to fluctuations in the power generation amount.
For this reason, even if the rotational speed of the engine fluctuates, the driving force of the motor can be gradually changed, so that the acceleration / deceleration feeling of the vehicle can be changed according to the speed change operation.
Therefore, the operating state of the engine can be matched with the drive feeling of the occupant, and the acceleration / deceleration feeling of the vehicle can be reliably generated according to the speed change operation.

In one embodiment of the present invention, clutch shift mode control means is provided that does not supply power from the battery during downshifting during the shift.
According to the above configuration, the driving force of the motor is temporarily reduced by not supplying power from the battery at the time of shift down by the clutch transmission mode control means.
For this reason, at the time of downshifting, the feeling of acceleration of the vehicle temporarily decreases, and it is possible to give the occupant the feeling of having stepped on the clutch pedal in the manual transmission.
Therefore, a more sporty drive feeling can be given to the occupant. Moreover, since it is possible to suppress taking out of the stored electric power from the battery, fuel consumption can be improved.

In an embodiment of the present invention, the predetermined condition for selecting the stepped transmission mode is a case where an occupant instruction signal is received.
According to the above configuration, the stepped speed change mode is selected when an occupant instruction signal is received, and therefore, engine control that enhances drive feeling is performed when the occupant requests.
Therefore, when the occupant does not intend, engine control that greatly changes the engine operating state is not performed. Therefore, drive feeling can be enhanced without giving the occupant anxiety.

In one embodiment of the present invention, the predetermined condition for selecting the continuously variable transmission mode is a case where the remaining charge of the battery is equal to or less than a predetermined value.
According to the above configuration, when the charge amount of the battery is small, the control is performed in the continuously variable transmission mode, and the control is performed in the stepped transmission mode in which the battery may be discharged during the shift. By preventing this, overdischarge of the battery can be suppressed.
Therefore, as a hybrid vehicle, it is possible to perform engine control that enhances drive feeling while ensuring minimum traveling performance.

In one embodiment of the present invention, there is provided control prohibiting means that does not perform engine control based on the shift control line changed by the control line changing means when the driving force change is equal to or less than a predetermined value. .
According to the above configuration, engine control is performed based on the shift control line only when the change in driving force is greater than a predetermined value.
For this reason, engine control that enhances drive feeling can be performed only when the change in driving force, which is particularly uncomfortable for passengers, is large, and in other cases, engine control that emphasizes fuel efficiency can be performed.
Therefore, while improving the drive feeling in the region where the occupant feels uncomfortable, it is possible to improve the fuel consumption in other cases.

According to the present invention, at the time of shifting in the stepped speed change mode, the engine speed changes rapidly and the engine operating state changes greatly, and the occupant recognizes that the engine operating state has changed. Can be made.
Therefore, in a control device for a series hybrid vehicle, it is configured to obtain a stepped speed change state and a stepless speed change state, and at the time of gear shifting in the stepped speed change state, the drive feeling is improved without causing the passenger to feel uncomfortable. can do.

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

  FIG. 1 is an overall schematic diagram of a series hybrid vehicle according to the present embodiment. A drive motor 1 mounted on the vehicle rotates the left and right drive wheels 3R and 3L via a differential device 2. On the other hand, the engine 4 is connected to a motor / generator 5 and is mounted on a vehicle as a power source for driving the motor / generator 5 to generate electric power.

  The power generated by the motor / generator 5 is once converted into a direct current by the AC-DC converter 6 and sent to the distributor 7. The distributor 7 distributes the generated power as it is to the drive power that is transmitted to the drive motor 1 side and the stored power that is stored on the high voltage battery 8 side.

  The electric power transmitted as the driving electric power is converted again into an alternating current by the DC-AC converter 9 and supplied to the driving motor 1 to be used as a driving force for driving the vehicle.

  On the other hand, the electric power transmitted as the stored electric power is sent to and stored in the high voltage battery 8 as the direct current. The stored stored power is supplied from the high voltage battery 8 to the drive motor 1 as necessary.

  The driving state of this series hybrid vehicle is controlled by the following basic control. First, when the vehicle is started or when the torque is low, the power stored in the high voltage battery 8 is supplied to the drive motor 1 to drive the vehicle.

  Further, at the time of medium torque, the engine 4 is started by the motor / generator 5, the motor / generator 5 is driven by the engine 4, and the generated electric power generated by this driving is supplied to the driving motor 1 to drive the vehicle. To drive.

  Further, at the time of high torque, the generated power from the engine 4 and the stored power from the high voltage battery 8 are supplied to the driving motor 1 to drive the vehicle.

  On the other hand, when the amount of power stored in the high-voltage battery 8 decreases, the engine 4 is driven so that the amount of power generated is greater than that required by the drive motor 1, and the surplus generated power is generated. The high voltage battery 8 is supplied to charge the high voltage battery 8.

  FIG. 2 is a system block diagram of the series hybrid vehicle. In this system block, a PCM 10 (powertrain control module) for controlling each device is provided in the center. By this PCM 10, the fuel injection nozzle 11 of the engine 4, the throttle valve 12 of the engine 4, the motor generator 5 controls a generator controller 13 that controls a load torque of 5, a motor controller 14 that controls the rotational driving force of the driving motor 1, and a distributor 15 that switches a power supply path.

  The PCM 10 also detects a battery current / voltage sensor 16 that detects the amount of charge of the high-voltage battery 8, a vehicle speed sensor 17 that detects the speed of the vehicle, and a passenger's accelerator operation as input means for various information. An accelerator position sensor 18 that performs the operation, a stepped gear change mode switch 19 that is operated by the occupant, a shift sensor 20 that detects a shift operation performed by the occupant, an engine speed sensor 21 that detects the rotational speed of the engine 4, and the engine 4 An air flow sensor 22 that detects the amount of intake and intake air is connected.

  FIG. 3 is an engine control map for obtaining a control line used by the PCM 10 for output control of the engine 4. In this engine control map, the balance torque shown on the vertical axis is the torque that balances the torque of the engine 4 and the torque of the drive motor 1. A line indicated by a symbol P is an equal output line of the driving motor 1. The line indicated by the symbol Q is the maximum torque line of the engine 4. In addition, a substantially circular line is an equi-efficiency line, and the closer to the center, the higher the efficiency.

A solid line and a line indicated by symbol L are control lines for high efficiency control, and output control of the engine 4 is basically performed based on the high efficiency control line L.
The low engine speed range indicated by the symbol L1 is a region where the power generated by the engine 4 cannot be sufficiently obtained until the vehicle is driven. In this region indicated by L1, the power supply from the high voltage battery 8 is exclusively used. The drive motor 1 is driven. The region indicated by the symbol L2 is a region exceeding the maximum torque of the engine 4 and is a region where power is supplied from the high voltage battery 8 in addition to the maximum generated power from the motor / generator 5.

  FIG. 4 is an output map of the drive motor 1 which is a premise for controlling the features of the present embodiment. This output map of the driving motor 1 shows the relationship between the vehicle speed and the driving force when the accelerator opening is the same, and is a map for determining the driving force generated by the driving motor 1. Note that a plurality of output maps are set according to each accelerator opening, but in the present embodiment, description will be given using one of them.

  In this output map, a line V indicated by a solid line is a target driving force line of the driving motor 1 in the continuously variable transmission mode, and a line M indicated by a broken line is a target driving of the driving motor 1 in the stepped transmission mode. Power line.

In the continuously variable transmission mode, a high driving force line V1 is set in the low speed region, a driving force line V2 that gradually decreases in the downward convex curve line is set in the middle and high rotation regions, and the driving force is rapidly reduced in the maximum rotational region. Force line V3 is set. Thus, in the continuously variable transmission mode, in principle, the driving motor 1 is set to be controlled by one target driving force line corresponding to the vehicle speed.
The rotational speed (vehicle speed) of the driving motor 1 is set so as to be changed by increasing / decreasing the frequency of the alternating current, and the rotating torque (driving force) of the driving motor 1 is changed by increasing / decreasing the voltage value. It is set.

  On the other hand, in the stepped transmission mode, a plurality of driving force lines M are set like a manual transmission, and the first speed line, the second speed line, the third speed line, the fourth speed line from the low speed range to the high speed range. A plurality of driving force lines M are set so as to draw a torque curve that excites the intermediate rotation range. As described above, in the stepped speed change mode, the drive motor 1 is controlled by a plurality of target driving force lines, so that the occupant feels as if driving a vehicle equipped with a stepped transmission. Can be given.

  The stepped transmission mode and the stepless transmission mode can be switched in principle by switching the stepped transmission mode switch 9 described above.

  For this reason, the occupant can select the stepped speed change mode when he wants to obtain a sporty drive feeling, and can select the continuously variable speed mode when he wants to enjoy a relaxed drive.

  However, even if such a stepped speed change mode is selected, in a series hybrid vehicle such as this embodiment, the change in the rotational speed of the engine 4 does not correspond to the acceleration feeling of the vehicle. A passenger who gets used to the vehicle feels uncomfortable because the acceleration of the vehicle does not correspond to the engine sound.

Therefore, in this embodiment, this uncomfortable feeling is alleviated by performing control according to the following control flowchart.
FIG. 5 and FIG. 6 show control flowcharts that characterize this embodiment. In the following description, S indicates a step.

  First, in S1, information necessary for control is read from each sensor, and in S2, it is determined whether the present is in the stepped speed change mode. Here, if it is determined that the stepped speed change mode is not being set (NO determination), that is, if it is determined that the stepless speed change mode is being set, the process proceeds to the flowchart of FIG. 6 via (1).

  If YES is determined in S2, the process proceeds to S3 to determine whether or not there is a gear shift operation. Here, also when it is determined that there is no speed change operation (NO determination), the process proceeds to (1).

  If YES is determined in S3, the process proceeds to S4 to determine whether the engine 4 is being driven. When it is determined that the engine 4 is not being driven (NO determination), the process proceeds to (1).

  Further, in the case of YES determination in S4, the process further proceeds to S5 to determine whether or not the stored amount of the high voltage battery 8 is ¼ or more. Also here, when it is determined that the battery storage amount is less than ¼ (NO determination), the process proceeds to (1) as in the other steps.

  If all the above determinations are YES, the process proceeds to S6, and how much the driving force change of the driving motor 1 is required by the current shifting operation from the output map (see FIG. 4). Judging.

  This change in driving force greatly depends on the number of shift stages, the accelerator opening, etc., and increases as the number of shift stages increases, and increases even when the accelerator opening is large. For example, as shown in the output map of FIG. 4, the case where the shift from the 4th speed A point to the 2nd speed B point is compared with the case where the 4th speed A point shifts to the 3rd speed C point. It can be seen that the driving force change is larger when the speed is shifted from the second speed to the second speed. For this reason, a larger driving force change is required when shifting from the fourth speed to the second speed.

  Next, the process proceeds to S7, where it is determined whether the driving force change is greater than or equal to a predetermined amount. As the value of the predetermined amount, for example, it is conceivable to set a relatively small driving force change amount as shown in “T-T ′” between the fourth speed and the third speed in FIG.

  If it is determined in S7 that the amount is not equal to or greater than the predetermined amount (NO determination), the process proceeds to (1). If YES is determined in S7, the process proceeds to S8.

  Here, first, the control in the continuously variable transmission mode, which is the basic control, will be described with reference to the control flowchart of FIG. 6 after (1).

  First, information for calculating the electric energy is read in S21. Next, based on the read information in S22, the required power amount in the entire vehicle is calculated. Specifically, the acceleration request of the occupant is determined from the accelerator opening, and the amount of electric power that provides the driving force that matches the acceleration request of the vehicle is calculated. Then, the required power amount is calculated from the excess and deficiency, and the required power amount of the entire vehicle is calculated.

  Then, the process proceeds to S23, where it is determined whether power generation by the motor / generator 5 is necessary. If it is determined that it is not necessary (NO determination), the process proceeds to S30. If it is determined that it is necessary (YES determination), the process proceeds to S24.

  In S24, it is determined whether the engine 4 is being driven. If it is determined that the engine 4 is not being driven (NO determination), the process proceeds to S25 and the engine 4 is started. When the engine 4 is started, the engine 4 is started by cranking the engine 4 using the motor / generator 5 as a starter of the engine 4. Thus, when the engine 4 is started, the engine 4 rotates the motor / generator 5 to which the load torque is applied, thereby generating electric power.

If YES is determined in S24, or after the engine 4 is started in S25, the process proceeds to S26. In S26, the operating point of the engine 4 on the high-efficiency control line L from which the required power amount can be obtained is determined from the engine control map (see FIG. 3).
For example, as shown in FIG. 3, a point “Y” on the high-efficiency control line L having a rotation speed of about 2000 rotations of the engine 4 is determined as the operating point of the engine 4.

  Next, in S27, the high efficiency line L ′ is set as the control line. That is, by controlling the drive of the engine 4 in the most efficient state, the engine speed is controlled so as not to change suddenly.

  For example, when the current operating point of the engine 4 is at the point “X”, a high efficiency line L ′ indicated by a solid line from “X” to “Y” is set as a control line.

  Further, in S28, the load torque of the motor / generator 5 is controlled so as to trace the high efficiency line L ′ set in S27. Specifically, in the case shown in FIG. 3, the fuel injection amount and the throttle opening are controlled so that the engine speed gradually decreases, and the load torque of the motor / generator 5 is controlled to be increased.

  Finally, in S29, the electric power generated in this way is supplied from the motor / generator 5 and the shortage is supplied from the high-voltage battery 8 to the driving motor 1, thereby controlling the vehicle to be driven. .

  On the other hand, if it is determined in S23 that power generation by the motor / generator 5 is not necessary, the process proceeds to S30 to determine whether the engine 4 is being driven. If it is determined that the engine 4 is being driven (YES determination), the process proceeds to S31 and the engine 4 is stopped. Thereby, when the power generation is unnecessary, the driving of the engine 4 can be stopped, and the fuel consumption by the engine 4 can be suppressed.

  If it is determined in S30 that the engine 4 is not being driven (NO determination), since the engine 4 has already stopped, the process directly proceeds to S32. Moreover, also when it transfers to S31 and the engine 4 is stopped, it transfers to S32.

  In S32, since the engine 4 is not driven and the motor / generator 5 does not generate electric power, power is supplied only from the high voltage battery 8 to the driving motor 1 to control the vehicle to be driven.

In contrast to the control in the continuously variable transmission mode, which is the basic control, the control flowchart in and after S8 shows the control in the stepped transmission mode, which is a characteristic control of the present embodiment.
In S8, first, information for calculating the electric energy is read. Next, in S9, the required power amount for the entire vehicle is calculated based on this information. Specifically, similarly to S22, the required power amount for the entire vehicle is calculated by calculating the accelerator opening and the battery charge amount, and further, the required power amount from the operation of the shift sensor 20.

And it shifts to S10 and determines the engine 4 operating point on the high-efficiency control line where the required power amount can be obtained from the engine control map (see FIG. 3).
For example, as in S26, as shown in FIG. 3, the point “Y” on the high-efficiency control line L of about 2000 revolutions is determined as the operating point of the engine 4.

  Next, the process proceeds to S11, and a control line for increasing the speed of change of the rotational speed of the engine 4 is set as a shift control line. For example, as shown in FIG. 3, a speed change control line Z indicated by a broken line in which the engine speed changes at a stretch is set between a point “X” that is the current operating point of the engine 4 and a target point “Y”. To do.

  Next, the process proceeds to S12, and the load torque of the generator 5 is controlled so as to trace the shift control line Z set in S11. Specifically, by slightly increasing or decreasing the load torque of the generator 5, the generator 5 and the engine 4 are controlled so that the change in the rotational speed of the engine 4 changes faster than when the high-efficiency line L ′ is traced. To do.

  Next, the process proceeds to S13 and it is determined whether or not the shift is down. When it is determined that the shift is down (YES determination), the process proceeds to S14 to supply power to the drive motor 1 while maintaining the charge / discharge amount of the high-voltage battery 8.

  On the other hand, when it is determined that the shift is not down, that is, the shift is up (NO determination), the process proceeds to S15 so that the motor torque is gradually decreased while the charge / discharge amount of the high voltage battery 8 is increased. Power is supplied to the drive motor 1.

  That is, the torque control method of the drive motor 1 is set to be changed depending on whether it is downshifted or upshifted, and there is no charge / discharge from the high voltage battery 8 during the downshift, and the motor generator 5 The generated power of the motor / generator 5 is controlled to be supplied to the driving motor 1 as it is, and the generated power of the motor / generator 5 is charged into the high voltage battery 8 at the time of upshifting, and the amount supplied to the driving motor 1 is controlled. Is controlled to decrease.

In this way, by changing the power supply control of the drive motor 1 between upshifting and downshifting, it is possible to obtain a feeling of vehicle acceleration / deceleration that matches the occupant's request for shift operation.
Thus, the control at the time of shifting in the stepped speed change mode is completed, and the process shifts to return to prepare for the next control.

  7 and 8 are time charts showing control states during downshifting and upshifting. In each figure, the horizontal axis represents time, and the vertical axis represents the change state of various values. From the top, the accelerator opening change, the shift stage number change, the engine speed change, and the power generation amount change of the motor / generator 5 are changed. FIG. 4 shows a change in torque generated by the drive motor 1 and a change in charge / discharge of the high voltage battery 8.

FIG. 7 shows a control state at the time of downshifting.
If the shift position is shifted down from the third speed to the second speed with the accelerator opening being constant, the engine speed increases rapidly and increases in an upwardly convex curved line. This is because the engine speed is changed by the shift control line (Z) as described above.
If the engine speed is changed on the high-efficiency line (L ′), the engine speed will change gradually as shown by the alternate long and short dash line. In this case, the occupant increases the engine speed. You may not be able to recognize it clearly and feel uncomfortable.
The change in the engine speed may be displayed not only on the engine sound but also on a display monitor or the like (not shown) in the passenger compartment so as to be recognized by the occupant.

  For this reason, according to the present embodiment, when the occupant performs a downshift operation, the engine speed immediately increases, so that an increase in engine sound can be felt, and the occupant does not feel uncomfortable.

  Further, in order to cause such a change in the engine speed, control is performed so as to reduce the load torque of the motor / generator 5, so that the power generation amount of the motor / generator 5 is greatly reduced as shown in the figure. With respect to this reduced power generation amount, the charge / discharge amount of the high-voltage battery 8 is constant (no power is taken in or out), so the motor torque of the drive motor 1 is the same as the power generation amount of the motor / generator 5. To decrease.

  Thus, the driving force of the vehicle is temporarily reduced by reducing the motor torque of the driving motor 1. This decrease in driving force provides a feeling of acceleration / deceleration that approximates the state in which the clutch pedal is depressed in a vehicle equipped with a manual transmission. For this reason, the drive feeling at the time of downshifting in the stepped speed change mode can be made more sporty.

On the other hand, FIG. 8 shows a control state at the time of upshifting.
If the shift position is shifted up from the second speed to the third speed with the accelerator opening being constant, the engine speed drops sharply and falls in a downwardly convex curved line. This is because the engine speed is changed by the shift control line (Z) as described above.
In this case as well, if the engine speed is changed on the high efficiency line (L ′), the engine speed changes slowly as shown by the alternate long and short dash line. May not be clearly recognized, and there may be a sense of incongruity.

  Therefore, even in the case of upshifting, according to the present embodiment, when the occupant performs the upshifting operation, the engine speed decreases immediately, so that the occupant does not feel uncomfortable.

  The engine speed is also changed by controlling the load torque of the motor / generator 5 to be increased. In this case, the amount of power generated by the motor / generator 5 is greatly increased as shown in the figure. . If the charging / discharging amount of the battery is constant with respect to the increasing power generation amount (two-dotted line), the motor torque of the driving motor 1 is also greatly increased. There is a risk that the driving torque of the motor increases.

  For this reason, in the case of upshifting, a part of the increased power generation amount is supplied to the high voltage battery 8 and charged, so that the power supplied to the drive motor 1 does not increase excessively. The motor torque of the drive motor 1 is gradually increased.

  In this way, by controlling the engine speed and the torque control of the drive motor 1, the drive feeling in the manual shift mode is enhanced.

Next, the effect of this embodiment is demonstrated.
In the control apparatus for the series hybrid vehicle according to this embodiment, when the speed change operation is performed with the stepped speed change mode selected, the engine speed changes along the speed change control line (Z) when the engine speed changes. Is controlled to change rapidly.
For this reason, at the time of shifting in the stepped transmission mode, the rotational speed of the engine 4 changes quickly, and it is possible to make the occupant recognize that the operating state of the engine 4 has changed significantly.
Therefore, in a control device for a series hybrid vehicle, it is possible to obtain a stepped speed change mode and a stepless speed change mode, and at the time of gear change in the stepped speed change mode, drive feeling is improved without causing the passenger to feel uncomfortable. can do.

Further, in this embodiment, at the time of upshifting, the driving power of the driving motor 1 gradually decreases by charging the high voltage battery 8 (accepting electric power) in accordance with the increase fluctuation of the power generation amount of the motor / generator 5. So that the power supply is controlled.
Thereby, even if the rotation speed of the engine 4 fluctuates greatly, the driving force of the driving motor 1 gradually changes, so that the acceleration / deceleration feeling of the vehicle can be changed according to the speed change operation.
Therefore, the operating state of the engine 4 can be matched with the occupant's drive feeling, and the acceleration / deceleration feeling of the vehicle can be reliably generated according to the speed change operation.

Further, in this embodiment, control is performed so that power is not supplied from the high voltage battery 8 at the time of downshift.
Thereby, at the time of downshifting, the driving force of the driving motor 1 is temporarily reduced.
For this reason, at the time of downshifting, the feeling of acceleration of the vehicle temporarily decreases, and it is possible to give the occupant the feeling of having stepped on the clutch pedal in the manual transmission.
Therefore, a more sporty drive feeling can be given to the occupant. In addition, since it is possible to prevent the stored power from being taken out from the high-voltage battery 8, fuel consumption can be improved.

In this embodiment, the stepped transmission mode is selected by the passenger operating the stepped transmission mode switch 9.
As a result, when there is a request from the occupant, engine control that enhances drive feeling is performed.
Therefore, when the occupant does not intend, the engine control that greatly changes the operating state of the engine 4 is not performed, so that the drive feeling of the vehicle can be enhanced without giving the occupant anxiety.

In this embodiment, the continuously variable transmission mode is selected when the stored amount of the high voltage battery 8 is ¼ or less.
As a result, when the amount of power stored in the high-voltage battery 8 is small, the control is always performed in the continuously variable transmission mode, and the step-change mode in which the high-voltage battery 8 may be discharged during a shift. By avoiding the control in step S1, the overdischarge of the high voltage battery 8 can be suppressed.
Therefore, as a hybrid vehicle, it is possible to perform engine control that enhances drive feeling while ensuring minimum traveling performance.

In this embodiment, the engine control based on the shift control line (Z) is controlled so as not to be performed when the driving force change is equal to or less than a predetermined amount (for example, a change amount between P-P '). .
Thus, engine control is performed based on the shift control line (Z) only when the driving force change is greater than a predetermined amount (a change amount between P-P ′).
For this reason, engine control that enhances drive feeling can be performed only when the change in driving force, which is particularly uncomfortable for passengers, is large, and in other cases, engine control that emphasizes fuel efficiency can be performed.
Therefore, while improving the drive feeling in the region where the occupant feels uncomfortable, it is possible to improve the fuel consumption in other cases.

Next, another embodiment will be described with reference to FIGS.
FIG. 9 is a control flowchart corresponding to FIG. 5, and FIG. 10 is a time chart showing a control state at the time of downshift corresponding to FIG. The same steps as those in the above-described embodiment are denoted by the same reference numerals as those in FIGS. 5 and 7, and the description thereof is omitted.

  In this embodiment, power is supplied from the high-voltage battery 8 to the driving motor 1 at the time of downshifting so that the motor torque of the driving motor 1 is gradually increased.

  Specifically, as shown in FIG. 9, it is determined whether or not the shift is down in S13, and if it is determined that the shift is down (YES determination), the process proceeds to S114, and the high voltage battery is determined in S114. Control is performed to supply power to the drive motor 1 so that the motor torque gradually increases while the charge / discharge amount of 8 is reduced.

  Thus, by controlling, as shown in FIG. 10, even if the power generation amount of the motor / generator 5 is reduced at the time of downshifting, the reduced power is discharged (supplied) from the high voltage battery 8, The motor torque of the drive motor 1 increases gradually without dropping once (dashed line).

As described above, according to the present embodiment, the motor torque of the driving motor 1 gradually increases even during downshifting, so that the acceleration / deceleration feeling of the vehicle can be changed according to the speed change operation. it can.
Therefore, even during downshifting, the operating state of the engine 4 can be matched with the occupant's drive feeling, and the acceleration / deceleration of the vehicle can be reliably generated according to the speed change operation.

As described above, in the correspondence between the configuration of the present invention and the above-described embodiment,
The generator of the present invention corresponds to the motor / generator 5,
Similarly,
The battery corresponds to the high voltage battery 8,
The motor corresponds to the drive motor 1,
The shift mode control means corresponds to the control steps S2 and S5 of the PCM 10,
The engine control means corresponds to the control steps S26, S27, S28 of the PCM 10,
The control line changing means corresponds to the control steps S10, S11, S12 of the PCM 10,
The present invention is not limited to the above-described embodiments, but includes embodiments of control devices for all series hybrid vehicles.

  In the above-described embodiment, one shift control line (Z) has been described. However, a plurality of the shift control lines (Z) may be set and switched according to the operating state of the engine 4 or the like.

  In the above-described embodiment, the description has been made on the assumption that the occupant performs a shift operation. However, like a general automatic transmission, a shift is automatically performed on the vehicle side according to a vehicle speed, an accelerator opening degree, and the like. It may be applied as such.

1 is an overall schematic diagram of a series hybrid vehicle according to an embodiment of the present invention. The system block diagram of a series hybrid vehicle. Engine control map. Drive motor output map. The control flowchart of embodiment. The control flowchart of embodiment. The time chart which showed the control state at the time of downshift. The time chart which showed the control state at the time of shift up. The control flowchart of other embodiment. The time chart which showed the control state at the time of downshift of other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drive motor 4 ... Engine 5 ... Motor generator 8 ... High voltage battery 10 ... PCM
L '... High efficiency line Z ... Shift control line

Claims (6)

An engine, a generator connected to the output shaft of the engine, a battery that can be charged by at least power generation by the generator, and a motor that is driven by the generated power from the generator or the power from the battery to drive the vehicle A control device for a series hybrid vehicle comprising:
A speed change mode control means for selectively setting a stepless speed change mode for changing the drive output of the motor steplessly and a stepped speed change mode for changing the drive output of the motor stepwise;
Engine control means for controlling the drive state of the engine based on a high efficiency control line set so that engine efficiency is optimal;
Change the control line to the shift control line set so that the changing speed of the engine speed is larger than when based on the high-efficiency control line when shifting in the stepped shift mode when the engine is driven A control device for a series hybrid vehicle, comprising: When engine control is performed based on the shift control line changed by the control line changing means, the load torque of the generator is controlled so as to increase the change speed of the engine speed. And
2. The series hybrid according to claim 1, further comprising motor control means for supplying power so that the driving force of the motor is gradually changed by charging / discharging the battery as the power generation amount of the generator changes during shifting. Vehicle control device. 3. The control apparatus for a series hybrid vehicle according to claim 2, further comprising clutch shift mode control means that does not supply power from the battery during downshifting during the shift. The control apparatus for a series hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition for selecting the stepped transmission mode is a case where an occupant instruction signal is received. 4. The control apparatus for a series hybrid vehicle according to claim 2, wherein the predetermined condition for selecting the continuously variable transmission mode is a case where a remaining charge of the battery is equal to or less than a predetermined value. The series hybrid vehicle according to any one of claims 1 to 5, further comprising a control prohibiting unit that does not perform engine control based on the shift control line changed by the control line changing unit when the driving force change is equal to or less than a predetermined value. Control device.

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