JP5920607B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle control device, and more particularly, to a hybrid vehicle control device that realizes quick switching of a driving mode by quickly connecting a clutch when switching from motor driving to engine driving.

  In recent years, a hybrid electric vehicle that can arbitrarily transmit driving force of an engine and a motor to a driving wheel side has been put into practical use. For example, in the hybrid electric vehicle described in Patent Document 1, a motor is connected to the drive wheel side of the vehicle via a transmission, and an engine is connected to the motor via a clutch. When the clutch is disengaged, the engine is stopped and the motor travels to transmit the driving force of the motor to the driving wheel side. When the clutch is engaged, the motor travels to stop the motor and transmit the engine driving force to the driving wheel side. Motor / engine traveling is performed to transmit the driving force of the motor and engine to the drive wheel side.

  The switching of the driving mode is executed according to the driver's accelerator operation or increase / decrease in the SOC (State Of Charge) of the battery. For example, the accelerator is stepped on while the motor is running, and the motor driving force alone cannot respond to the acceleration request. At times, an instruction to switch to motor / engine running is issued. The switching of the running mode at this time is executed through a process of starting the stopped engine, and then connecting the clutch after synchronizing the input / output rotational speed of the clutch.

JP 2008-55993 A

  Since the rotational speed of the clutch output shaft at the time of vehicle acceleration is increasing with the vehicle speed, in order to synchronize the clutch input / output when switching the travel mode, the rotational speed of the clutch output shaft following the rising clutch output shaft is followed immediately after starting. It is necessary to quickly increase the engine rotation speed (= the rotation speed of the clutch input shaft). However, the technique of Patent Document 1 has a problem in that the increase in engine rotation speed becomes slow due to control factors, resulting in a delay in rotation synchronization and a delay in clutch connection.

  That is, as shown in the time chart of FIG. 4 showing the control status at this time, the rotational speed Nout of the clutch output shaft gradually increases with the vehicle speed as the accelerator is depressed while the motor is running. An instruction to switch to engine running is given to make up for the shortage. In response to this, the engine is started, and the engine rotational speed Ne is controlled in the increasing direction with a value obtained by adding a predetermined value α to the rotational speed Nout of the clutch output shaft as a target value Ntgt. When the rotation synchronization of the clutch input / output is completed due to the increase in the engine rotation speed Ne, the clutch connection is started, and the engine running is started when the clutch connection is completed.

  The target value Ntgt of the engine rotational speed Ne increases with the rotational speed Nout of the clutch output shaft. However, since the target value Ntgt is still low at the beginning of the instruction to switch to engine running, the engine rotational speed Ne based on the target value Ntgt. The rise will be slow. For this reason, the engine rotational speed Ne approaches the target value Ntgt in a ramp shape and the time required to reach it is prolonged, and the clutch connection is also delayed together with the delay in rotation synchronization. The delay in clutch connection means that the driving force corresponding to the acceleration request cannot be realized by switching to the rapid engine running, resulting in a problem that the acceleration response is deteriorated.

  The present invention has been made to solve such problems. The object of the present invention is to promptly increase the engine speed after starting a stopped engine when switching from motor travel to engine travel. It is an object of the present invention to provide a control device for a hybrid vehicle that can be raised to synchronize with the rotational speed of a clutch output shaft, and thus can realize a good acceleration response by quickly switching a running mode by clutch engagement.

  In order to achieve the above object, the invention of claim 1 is constituted by connecting an electric motor to a drive wheel of a vehicle and connecting an engine to the drive wheel via a clutch, and disconnecting the clutch. The motor driving mode for transmitting the driving force of the electric motor to the driving wheels while the driving force transmission from the engine is cut off and the engine driving mode for transmitting the driving force of the engine to the driving wheels by connecting a clutch are switched. In the control device for the traveling hybrid vehicle, when the clutch output rotational speed detecting means for detecting the rotational speed of the clutch output shaft extending from the clutch toward the drive wheel side and the switching instruction to the engine traveling mode are instructed, When the rotation speed of the clutch output shaft at the start of connection is predicted, and the rotation speed obtained by adding a predetermined value to the predicted rotation speed is instructed. Those having a target value setting means for setting a target value of the engine speed, and engine control means for controlling the engine rotational speed based on a target value set by the target value setting means.

According to a second aspect of the present invention, in the first aspect, the predetermined time from when the switching instruction is given to when the clutch is started includes the time required for starting the engine, and the engine speed after the completion of the start is a target value. It is set as a value that substantially corresponds to the sum of the required time to reach.
According to a third aspect of the present invention, in the second aspect , the length of the predetermined time is calculated according to the rotational speed of the clutch output shaft when the instruction to switch to the engine running mode is given, and the calculated predetermined time is predicted. Predicted time setting means for setting the time is provided, and the predicted time setting means sets the predicted time to the increasing side as the rotational speed of the clutch output shaft increases when an instruction to switch to the engine running mode is given.

According to a fourth aspect of the present invention, in the third aspect, the predicted time setting means increases the predicted time as the rate of increase in the rotational speed of the clutch output shaft when an instruction to switch to the engine running mode is given is increased. It is to set.
According to a fifth aspect of the present invention, in the third or fourth aspect, when the engine is in a cold state before the completion of warming up, the predicted time setting means compares the predicted time with that in a warm state after the completion of warming up. Is set to the increasing side.

  As described above, according to the hybrid vehicle control device of the first aspect of the present invention, when the switching instruction from the motor running to the engine running is given, the rotational speed of the clutch output shaft when the clutch is started is predicted. Then, a rotation speed obtained by adding a predetermined value to the predicted rotation speed is set as a target value of the engine rotation speed and applied to the engine rotation speed control. Therefore, because the engine speed increases rapidly based on the high target value and the clutch input / output rotation synchronization is completed quickly, the clutch connection timing is advanced and the switch to engine driving is completed early, and the acceleration request is made. It is possible to realize a good acceleration response according to the above.

In addition, since the rotation speed obtained by adding a predetermined value to the predicted rotation speed of the clutch output shaft is set as the target value, the engine rotation speed when the clutch is connected is higher than the rotation speed of the clutch output shaft, Generation of a momentary deceleration feeling can be prevented.
According to the hybrid vehicle control apparatus of the second aspect of the present invention, in addition to the first aspect, the predetermined time from when the switching instruction is given until the clutch is started is set to the time required for engine start and the completion of rotation synchronization. It was set as a value approximately corresponding to the sum of the required time. Accordingly, since the rotational speed of the clutch output shaft at the time when the rotational synchronization of the clutch input / output is completed based on the predetermined time is predicted as the predicted rotational speed, the engine rotational speed can be set based on the target value obtained from the predicted rotational speed. The switching of the running mode can be completed more quickly by synchronizing with the clutch output rotational speed as quickly as possible.

According to the hybrid vehicle control device of the third aspect of the present invention, in addition to the second aspect , the predicted time is set to increase as the rotational speed of the output shaft of the clutch increases. The higher the rotational speed of the clutch output shaft, the longer the required time until the engine rotational speed reaches the target value, but the predicted time is set to increase accordingly. For this reason, regardless of the rotational speed of the clutch output shaft, the rotational speed of the clutch output shaft can always be predicted based on an appropriate prediction time, and the engine rotational speed can be controlled based on a more appropriate target value.

  According to the control apparatus for a hybrid vehicle of a fourth aspect of the invention, in addition to the third aspect, the prediction time is set to be increased as the degree of increase in the rotational speed of the output shaft of the clutch is larger. The greater the degree of increase in the rotational speed of the clutch output shaft, the longer the required time until the engine rotational speed reaches the target value, but the predicted time is set to increase accordingly. For this reason, regardless of the degree of increase in the rotational speed of the clutch output shaft, the rotational speed of the clutch output shaft can always be predicted based on an appropriate prediction time, and thus the engine rotational speed can be controlled based on a more appropriate target value. .

  According to the hybrid vehicle control apparatus of the fifth aspect of the present invention, in addition to the third or fourth aspect, when the engine is in the cold state, the predicted time is set on the increasing side as compared with when the engine is in the cold state. Compared to the engine temperature, the engine start time is longer in the engine cold state, but the predicted time is set to the increase side accordingly. For this reason, regardless of whether the engine is warm or cold, the clutch output rotation speed can always be predicted based on an appropriate prediction time, and the engine rotation speed can be controlled based on a more appropriate target value. it can.

1 is an overall configuration diagram showing a vehicle to which a control device for a hybrid vehicle of the present invention is applied. It is a flowchart which shows the driving mode switching routine which HEVECU performs. It is a time chart which shows the engine rotation speed according to the switching instruction | indication of driving modes, and the control condition of a clutch. It is a time chart which shows the control condition corresponding to FIG. 3 by a prior art.

[First Embodiment]
Hereinafter, a first embodiment of a control apparatus for a hybrid vehicle embodying the present invention will be described.
FIG. 1 is an overall configuration diagram showing a vehicle to which a control device for a hybrid vehicle of the present invention is applied.
A motor 2 is connected to a front wheel (drive wheel) 1 of the vehicle via a differential device (not shown), and the driving force of the motor 2 is transmitted from the differential device to the front wheel 1. An engine 5 is connected to the front wheel 1 via a transmission 3 and a clutch 4 via a differential. When the clutch 4 is disconnected, the driving force of the engine 5 is cut off. On the other hand, when the clutch 4 is connected, the driving force of the engine 5 is transmitted from the differential device to the front wheels 1 through a predetermined gear stage of the transmission 3. ing. The engine 5 is provided with a generator 6, and when the engine 5 is operated, the generator 6 is rotationally driven to appropriately generate power, and the generated power is charged in a traveling battery (not shown).

  The driving mode of the vehicle is switched according to the operating state of the motor 2 and the engine 5 and the connection / disconnection state of the clutch 4. For example, in motor running using the motor 2 as a power source (motor running mode), the clutch 4 is disengaged and the engine 5 is stopped, the motor 2 is operated, and the driving force of the motor 2 is transmitted to the front wheels 1 to transmit the vehicle. To run. In engine running using the engine 5 as a power source (engine running mode), the motor 2 is stopped and the clutch 4 is connected to operate the engine 5, and the driving force of the engine 5 is transmitted to the front wheels via the clutch 4. 1 is transmitted to the vehicle. In motor / engine running (engine running mode) using the motor 2 and the engine 5 as power sources, the motor 2 is operated and the clutch 4 is connected to operate the engine 5. The driving force of the engine 5 is transmitted to the front wheels 1 to drive the vehicle.

  An inverter ECU 7 is connected to the motor 2, an engine ECU 8 is connected to the engine 5, a transmission ECU 9 is connected to the clutch 4, and these ECUs 7 to 9 are connected to a common HEVECU 10. The ECUs 7-9 are integrated and controlled by the HEVECU 10, and the motor 2, the engine 5, and the clutch 4 are operated in cooperation by driving and controlling devices corresponding to the ECUs 7-9 when the travel mode is switched. Note that the transmission ECU 9 is also connected to the transmission 3 and controls the shift stage thereof.

  For such control, the HEVECU 10 includes a vehicle speed sensor 12 for detecting the vehicle speed V, an accelerator sensor 13 for detecting the accelerator depression amount θacc, and an engine speed sensor for detecting the engine speed Ne (= clutch input speed Nin). 14. Detection information is input from various sensors such as a clutch output rotational speed sensor 15 (clutch output rotational speed detecting means) that detects the rotational speed Nout of the clutch output shaft.

  The HEVECU 10 calculates the driver's required torque based on the accelerator depression amount θacc, the vehicle speed V, etc., and calculates the SOC of the traveling battery that is the power source of the motor 2, and selects the traveling mode based on these required torque and SOC. (Running mode switching control means). For example, when the SOC of the traveling battery is equal to or higher than a predetermined value and the driver's required torque is less than the predetermined value, the motor traveling is selected as the traveling mode because the required torque can be achieved only by the driving force of the motor 2. Further, if the SOC falls below a predetermined value while the motor is running, the engine 5 is started with the clutch 4 disengaged, and the power generated by the generator 6 is charged into the running battery to recover the SOC.

  Further, for example, if the required torque exceeds a predetermined value due to depression of the accelerator while the motor is running, the motor / engine running is selected when the motor 2 cannot respond to the acceleration request only. On the other hand, when the SOC is extremely lowered and normal operation of the motor 2 cannot be expected, the engine traveling is selected and the motor 2 is caused to function as a generator to recover the SOC of the traveling battery.

  The HEVECU 10 calculates the driving force to be output from the motor 2 and the engine 5 from the torque required by the driver during motor driving and engine driving, and instructs the inverter ECU 7 and the engine ECU 8 to command the motor. In engine running, the required torque is distributed to the motor 2 side and the engine 5 side, and the driving force to be output by each is calculated and commanded to the inverter ECU 7 and the engine ECU 8.

Based on the driving force command from the HEVECU 10, the engine ECU 8 controls the fuel injection amount and injection timing of the engine 5 to operate the engine 5, and the inverter ECU 7 uses the electric power from the traveling battery to drive the motor 2 When the power generation command is received, the motor 2 is caused to function as a generator.
On the other hand, when the HEVECU 10 is instructed to switch from motor running to motor / engine running so as to cope with the increase in the required torque as described above, the transmission ECU 9 is in parallel with the driving force command to the inverter ECU 7 and the engine ECU 8. The clutch 4 is instructed to be connected. Since it is necessary to synchronize the rotational speeds Nin and Nout of the input / output shafts for clutch connection, the engine 5 that was stopped while the motor was running is first started, and then the engine rotational speed Ne is increased to rotate the clutch output. The speed Nout is approached (engine control means), and after the synchronization is completed, the clutch connection operation is performed (clutch control means).

  However, as described with reference to the time chart of FIG. 4, in the conventional technique of Patent Document 1, since the increase in the engine rotational speed Ne at this time is slow, the traveling mode can be made quicker by a delay in rotation synchronization and a delay in clutch connection. There was a problem that could not be switched to. The present inventor has set the target value Ntgt with an inappropriate increase in the engine rotational speed Ne, more specifically, the rotational speed Nout of the clutch output shaft at the time when the rotation synchronization is completed. It was noted that the control of the engine speed Ne was started based on the low target value Ntgt. Then, based on the knowledge that the engine speed Ne can be increased rapidly if the target value Ntgt at the time of completion of the rotation synchronization is applied from the beginning of the rotation speed control, the rotation speed of the clutch output shaft at the time of completion of the rotation synchronization. Nout is predicted, and the target value Ntgt obtained from the predicted value is applied from the beginning of the rotation speed control, and the details will be described below.

  FIG. 2 is a flowchart showing a travel mode switching routine executed by the HEVECU 10. The HEVECU 10 executes the routine at a predetermined control interval. Note that this routine is a process assuming a switching instruction from motor driving (motor driving mode) to motor / engine driving (engine driving mode), and although not described in detail, HEVECU 10 responds to a switching instruction for another driving mode. The routine to execute is also executed in parallel.

  First, in step S2, it is determined whether or not an instruction to switch from motor running (motor running mode) to motor / engine running (engine running mode) has been issued. If the motor is not currently running, or if there is no instruction to switch to motor / engine running (engine running mode) even while the motor is running, a determination of No (No) is made and the routine is once terminated. When the determination of Yes (Yes) is made in step S2, the process proceeds to step S4, and the clutch output rotational speed Nout after a predetermined predicted time Tpd has elapsed is predicted. Hereinafter, this predicted value is referred to as a predicted rotation speed Npd.

  In the present embodiment, the estimated time Tpd is the time required for starting the engine 5 and the time until the rotational speed of the engine 5 reaches the predetermined target value Ntgt after the start is completed and the rotation synchronization of the clutch input / output shaft is completed. A sum of required time (hereinafter referred to as required time for completion of rotation synchronization) is set. For this reason, the rotational speed Nout of the clutch output shaft when the predicted time Tpd has elapsed and the rotational synchronization of the clutch input / output shaft is completed is calculated as the predicted rotational speed Npd.

  For example, the predicted rotational speed Npd is predicted based on the instantaneous increase rate of the rotational speed Nout of the clutch output shaft at the time when the travel mode switching is instructed. However, the present invention is not limited to this, and any index can be used as long as it indicates the degree of increase in the rotational speed Nout of the clutch output shaft. For example, the amount of increase in the rotational speed Nout of the clutch output shaft may be calculated over a predetermined time from the travel mode switching instruction, and the predicted rotational speed Npd may be calculated based on this amount of increase.

  When the above process for predicting the rotational speed Nout of the clutch output shaft is completed, the routine proceeds to step S6, where a predetermined value α is added to the predicted rotational speed Npd to calculate a target value Ntgt for rotational speed control (target value setting means). The addition of the predetermined value α is a process for increasing the engine rotational speed Ne when the clutch is engaged to be higher than the rotational speed Nout of the clutch output shaft, thereby preventing the occurrence of an instantaneous deceleration feeling during acceleration.

  In the subsequent step S8, a command is output to the engine ECU 8, and the engine speed Ne is controlled based on the target value Ntgt. The rotational speed control feeds back the engine rotational speed Ne toward the target value Ntgt, and a known method such as PID control or PI control can be arbitrarily used as the control content. Due to the rotational speed control, the engine rotational speed Ne increases and approaches the target value Ntgt, and the HEVECU 10 determines whether or not the predicted time Tpd has elapsed in the subsequent step S10. While the determination is No, the process of step S8 is repeated, and when the determination is Yes, the process proceeds to step S12.

The progress determination of the predicted time Tpd in step S10 is to indirectly determine the completion of the rotation synchronization of the clutch input / output shaft, but is not limited to this. For example, the engine speed Ne is set to the target value Ntgt. You may determine directly whether it reached | attained.
In step S12, a value obtained by adding a predetermined value α to the rotational speed Nout of the clutch output shaft is set as the target value Ntgt. In step S14, a command is output to the engine ECU 8, and the engine rotational speed Ne based on the target value Ntgt is set. Execute feedback control. The target value Ntgt at this time gradually increases with the rotational speed Nout of the clutch output shaft.

  In the following step S16, a command is output to the transmission ECU 9 to control the clutch 4 in the connecting direction, and in step S18, it is determined whether or not the clutch connection is completed. Although the feedback control based on the target value Ntgt is continued, the engine rotational speed Ne gradually approaches and coincides with the rotational speed Nout of the clutch output shaft as the clutch 4 is connected, and when the determination in step S18 becomes Yes, the routine is performed. Exit. During the clutch 4 connection operation, the engine 5 may perform control based on engine torque instead of rotational speed control based on the target value Ntgt.

The engine speed Ne and the clutch 4 are controlled as shown in FIG. 3 according to the travel mode switching instruction by the processing of the HEVECU 10 described above.
While the motor is running, the engine 5 is stopped after the clutch 4 is disconnected, and the driving force of the motor 2 is transmitted to the front wheel 1 side so that the vehicle is running. For example, when the driver depresses the accelerator when starting or overtaking the vehicle, the rotational speed Nout of the clutch output shaft gradually increases with the vehicle speed V, and the required torque corresponding to the accelerator depressing is the maximum that can be achieved by the motor 2. When the driving force is exceeded, the HEVECU 10 instructs to switch to motor / engine running (engine running mode) to compensate for the shortage. In response to this, the engine 5 is started, the engine rotational speed Ne is controlled in the upward direction, and the clutch is connected when the rotation synchronization of the clutch input / output shaft is completed. When the clutch connection is completed, the motor / engine travel (engine travel mode) Is started.

  Control of the engine rotational speed Ne after engine start is executed based on the target value Ntgt. In the technique of the conventional patent document 1, a value obtained by adding a predetermined value α to the rotational speed Nout of the clutch output shaft is applied as the target value Ntgt. It was. On the other hand, in the present embodiment, a value obtained by adding a predetermined value α to the predicted rotational speed Npd after the predicted time period Tpd has elapsed from the beginning when the instruction to switch to motor / engine traveling (engine traveling mode) is made. This is applied as the target value Ntgt. For this reason, the high target value Ntgt is applied immediately after the completion of the engine start, and the engine speed Ne quickly increases. As the target value Ntgt is reached, the rotation synchronization of the clutch input / output shaft is completed earlier and the clutch is engaged. The start timing is advanced. As a result, the switching to the motor / engine running (engine running mode) is completed at an early stage upon completion of the clutch connection, and a favorable acceleration response in response to the acceleration request can be realized.

  In particular, in this embodiment, the sum of the time required for engine start and the time required for completion of rotation synchronization is used as the predicted time Tpd. Therefore, the rotation speed Nout of the clutch output shaft at the time when the rotation synchronization of the clutch input / output shaft is completed is predicted. Predicted as the rotational speed Npd. As a result, the clutch input / output shaft can be synchronized as quickly as possible based on the target value Ntgt obtained from the predicted rotational speed Npd, and the switching to the motor / engine running (engine running mode) can be completed more quickly.

  In the present embodiment, the sum of the required time for starting the engine and the required time for completion of rotation synchronization is set as the predicted time Tpd, but the present invention is not limited to this and can be arbitrarily changed. In any case, the target value Ntgt is set to a higher value than the prior art in accordance with the predicted time Tpd, and the rotation synchronization of the clutch input / output shaft is promptly performed based on the target value Ntgt. The same effect can be obtained.

  By the way, the time required for completing the rotation synchronization differs depending on the speed Nout of the clutch output rotating shaft when the travel mode is instructed and the degree of increase thereof (for example, the instantaneous increase rate). The higher the rotational speed Nout, the longer the time required to reach the target value Ntgt. The greater the degree of increase in the rotational speed Nout of the clutch output shaft, the longer the required time to reach the target value Ntgt. Further, the required time for starting the engine differs depending on whether the engine 5 is in a cold state before completion of warming up or in a warm state after completion of warming up. Tends to be prolonged.

  Therefore, if the predicted time Tpd is set according to the rotational speed Nout of the clutch output shaft at the time of switching instructions of these travel modes, the degree of increase in the rotational speed Nout of the clutch output shaft, or whether it is cold or warm, Further, the engine speed Ne can be controlled on the basis of an appropriate predicted rotation speed Npd, and hence an appropriate target value Ntgt. Hereinafter, the case where the predicted time Tpd is set based on the rotational speed Nout of the clutch output shaft is set as the second embodiment, and the case where the predicted time Tpd is set based on the increasing rate of the rotational speed Nout of the clutch output shaft is set as the third embodiment. A case where the predicted time Tpd is set based on whether the engine 5 is warm or cold will be described as a fourth embodiment.

The overall configuration diagram of the hybrid vehicle of each embodiment is the same as that described in the first embodiment, and the difference is that the process of step S3 for setting the predicted time Tpd in the travel mode switching routine shown in FIG. It is in the added point. Therefore, in each embodiment, common parts are denoted by the same member numbers, description thereof is omitted, and the processing is focused on step S3 which is a difference.
[Second Embodiment]
In the present embodiment, the predicted time Tpd is set according to the map on the left side shown in step S3 in FIG. 2, and the predicted rotational speed Npd is calculated in step S4 based on the predicted time Tpd. The characteristics of the map are such that the predicted time Tpd is set to be increased as the rotational speed Nout of the clutch output shaft when an instruction to switch to motor / engine running (engine running mode) is made. The higher the rotational speed Nout of the clutch output shaft, the longer the time required for the engine rotational speed Ne to follow and reach, but the predicted time Tpd is set to increase accordingly (predicted time setting means). .

For this reason, an appropriate predicted rotational speed Npd corresponding to the completion of the rotational synchronization of the clutch input / output shaft can always be predicted regardless of the level of the rotational speed Nout of the clutch output shaft when the travel mode switching instruction is issued. The engine speed Ne can be controlled based on the appropriate target value Ntgt.
[Third Embodiment]
In the present embodiment, the predicted time Tpd is set according to the central map shown in step S3 in FIG. 2, and the predicted rotational speed Npd is calculated in step S4 based on the predicted time Tpd. The characteristic of the map is that the predicted time Tpd is set to increase as the rate of increase in the rotational speed Nout of the clutch output shaft when an instruction to switch to motor / engine running (engine running mode) is made. Yes. Similar to the rotational speed Nout of the clutch output shaft of the second embodiment, the higher the increase rate, the longer the time required for the engine rotational speed Ne to follow and reach, but the predicted time Tpd is set to increase accordingly. (Estimated time setting means).

Therefore, regardless of the increase rate of the rotational speed Nout of the clutch output shaft at the time of the travel mode switching instruction, it is possible to always calculate an appropriate predicted rotational speed Npd corresponding to the completion of the rotational synchronization of the clutch input / output shaft, Therefore, the engine speed Ne can be controlled based on a more appropriate target value Ntgt.
[Fourth Embodiment]
In this embodiment, the predicted time Tpd is set according to the map on the right side shown in step S3 in FIG. 2, and the predicted rotational speed Npd is calculated in step S4 based on the predicted time Tpd. As the characteristics of the map, one of high and low two types of prediction time Tpd is set according to the engine temperature when the instruction to switch to motor / engine driving (engine driving mode) is made (prediction) Time setting means). Specifically, a short predicted time Tpd is set in the engine temperature state, and a long predicted time Tpd is set in the engine cold state. The cold state / temperature state of the engine 5 may be determined based on the elapsed time from the end of the previous engine operation, or may be determined based on the detection information of the temperature sensor attached to the engine 5.

Therefore, an appropriate predicted rotational speed Npd corresponding to the completion of the rotation synchronization of the clutch input / output shaft can always be calculated regardless of whether the engine 5 is warm or cold when the travel mode switching instruction is issued. Thus, the engine speed Ne can be controlled based on a more appropriate target value Ntgt.
Instead of switching the predicted time Tpd stepwise as described above, the predicted time Tpd is continuously set according to the elapsed time from the end of engine operation and the detected engine temperature, as shown by the broken line in FIG. May be.

  This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the motor 2 and the engine 5 are connected in parallel to the differential device of the front wheel 1 that is the drive wheel, but the present invention is not limited to this layout. For example, the motor 2, the clutch 4, and the engine 5 are connected in series to the differential, and the clutch 4 is disconnected when the motor is running in the motor running mode, and the clutch is used when the engine running and the motor / engine running are the engine running modes. 4 may be connected. Furthermore, it is not always necessary to provide engine travel as the travel mode, and the engine travel may be omitted.

  Further, in the above embodiment, the target value Ntgt is obtained from the predicted rotational speed Npd when an instruction to switch to motor / engine driving (engine driving mode) is given, and the single target value Ntgt is rotated from the beginning of the switching instruction. Although it has been applied to the control of the engine speed Ne until the synchronization is completed, if a change occurs in the degree of increase in the rotational speed Nout of the clutch output shaft together with the vehicle speed V during that time, it becomes an error factor of the predicted rotational speed Npd.

  Therefore, for example, the target value Ntgt may be updated every predetermined time, and the updated target value Ntgt may be applied to sequential control. Specifically, when a predetermined time elapses from the beginning of the switching instruction, the rotational speed Nout of the clutch output shaft after the predicted time Tpd (a value obtained by subtracting the predetermined time) is predicted to obtain the target value Ntgt and apply it to the control. This process is sequentially repeated every predetermined time. As a result, even if there is a change in the degree of increase in the rotational speed Nout of the clutch output shaft between the instruction to switch the travel mode and the completion of clutch engagement, the target value Ntgt increases or decreases accordingly, and always reaches the appropriate target value Ntgt. Based on this, it is possible to realize more appropriate control of the engine speed Ne.

  In the second embodiment, the predicted time Tpd is set based on the rotational speed Nout of the clutch output shaft. In the third embodiment, the predicted time Tpd is set based on the increasing rate of the rotational speed Nout of the clutch output shaft. In the embodiment, the predicted time Tpd is set according to the warm / cold state of the engine 5, but it is needless to say that these may be arbitrarily combined.

1 Front wheel (drive wheel)
2 Motor 4 Clutch 5 Engine 8 Engine ECU (Engine control means)
9 Transmission ECU (Clutch control means)
10 HEVECU (travel mode switching control means, target value setting means)
15 Clutch output rotation speed sensor (clutch output rotation speed detection means)

Claims (5)

The electric motor is connected to the driving wheel of the vehicle, and the engine is connected to the driving wheel via a clutch.
A motor travel mode for transmitting the driving force of the electric motor to the driving wheels in a state where the clutch is disconnected and the driving force transmission from the engine is cut off, and the driving force of the engine is driven by connecting the clutch. In a control device for a hybrid vehicle that travels by switching between engine travel modes transmitted to wheels,
Clutch output rotational speed detection means for detecting the rotational speed of a clutch output shaft extending from the clutch toward the drive wheel;
When an instruction to switch to the engine travel mode is given, the rotational speed of the clutch output shaft when the clutch starts to be connected is predicted, and the rotational speed obtained by adding a predetermined value to the predicted rotational speed is Target value setting means for setting as a target value of the rotational speed of the engine when the switching instruction is given;
An engine control means for controlling the engine rotation speed based on the target value set by the target value setting means. A control apparatus for a hybrid vehicle, comprising: The predetermined time from when the switching instruction is given to when the clutch starts to be engaged is the time required for starting the engine and the time required for the engine speed to reach the target value after the start is completed. The hybrid vehicle control device according to claim 1, wherein the control device is set as a value substantially corresponding to the sum of the two. A predicted time setting means for calculating the length of the predetermined time according to the rotational speed of the clutch output shaft when the switching instruction to the engine running mode is given, and setting the calculated predetermined time as the predicted time; Prepared,
3. The hybrid according to claim 2 , wherein the predicted time setting means sets the predicted time to an increase side as the rotational speed of the clutch output shaft is higher when an instruction to switch to the engine travel mode is given. Vehicle control device. The predictive time setting means sets the predictive time to an increase side as the rate of increase in the rotational speed of the clutch output shaft when a command to switch to the engine travel mode is made is large. Item 4. The control device for a hybrid vehicle according to Item 3. The predicted time setting means sets the predicted time to an increase side when the engine is in a cold state before completion of warm-up compared to a warm state after completion of warm-up. The control apparatus of the hybrid vehicle of Claim 3 or 4.

Images