JP2011020503A - Hybrid power device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid power device suppressing the occurrence of various problems caused by an increase in the output torque of a motor when starting shift processing to a low gear position side by a transmission in such a state that the motor outputs torque to a rotary output shaft. <P>SOLUTION: The hybrid power device 2 for a vehicle includes: a main power source 4 for transmitting torque to the rotary output shaft 6; and an MG2 for transmitting torque through the transmission 14 to the rotary output shaft 6. An HV-ECU 30 restricts the increase in output torque TM2 of the MG2 during a period since it is determined that down-shift by the transmission 14 in a state in which the MG2 outputs torque to the rotary output shaft 6 until transmission processing based on the determination is started. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid power unit including a main power source that transmits torque to a rotation output shaft and an electric motor that transmits torque to the rotation output shaft via a transmission.

  Conventionally, as this kind of hybrid power unit, for example, there is one described in Patent Document 1 as a hybrid power unit for a vehicle. In conventional hybrid power devices including those described in Patent Document 1, for example, rotational output is generated by at least one of torque transmitted from a main power source including an internal combustion engine and torque transmitted from a motor via a transmission. The shaft is driven.

  In such a hybrid power unit, when a shift to the low gear stage is performed by the transmission in a state where the motor is outputting torque to the rotation output shaft as in kick-down gear shifting, the motor rotates to the rotation output shaft. The torque transmitted to can be increased.

JP 2007-112349 A

  By the way, after the shift determination to the low shift stage side by the transmission in a state where the electric motor is outputting torque to the rotation output shaft, the shift process based on the shift determination is actually started. There may be a time delay. As a cause of such a time delay, for example, there is a shift start delay request for starting processing of the internal combustion engine. That is, the shift start delay request for the start process of the internal combustion engine is issued when the start process of the internal combustion engine 16 is executed when the shift determination is made, and the request is issued. In order to give priority to the completion of the start process over the shift process, the start of the shift process based on the shift determination is suspended until the start process is completed. However, there is a time delay between the shift determination being made and the shift process based on the shift determination actually being started. During this time delay, the output of the motor is based on an increase in the accelerator opening. If the output torque of the electric motor becomes large when the torque increases and the shift process is started, it is impossible to avoid various problems caused by this. That is, when the shift process is started while the output torque of the electric motor is large, among a plurality of friction engagement elements (clutch and brake) constituting the transmission, the engagement state is maintained until the shift process is started. The shock when releasing the frictional engagement element becomes large.

  On the other hand, in order to cope with such a problem, it is conceivable to reduce the output torque of the motor to a predetermined value or less when starting the shift process. However, in this case, if the output torque of the motor increases during the period from the determination of the shift to the start of the shift process, it takes a long time until the output torque of the motor becomes equal to or less than the predetermined value. Therefore, there arises a new problem that the start of the shift process is delayed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to start a shift process to the low gear stage by the transmission in a state where the electric motor is outputting torque to the rotation output shaft. It is an object of the present invention to provide a hybrid power unit that can suppress the occurrence of various problems caused by the output torque of the electric motor becoming large.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
(1) The invention according to claim 1 is a hybrid power unit including a main power source that transmits torque to the rotation output shaft, and an electric motor that transmits torque to the rotation output shaft via a transmission. The shift process based on the shift determination is started after the shift determination to the low shift stage by the transmission in a state where the electric motor is outputting torque to the rotation output shaft. The gist of the invention is that it includes an output torque limiting means for limiting an increase in the output torque of the electric motor during the period.

  According to this configuration, the shift process based on the shift determination is started after the shift determination to the low gear stage by the transmission in a state where the electric motor is outputting torque to the rotation output shaft. During this period, the increase in the output torque of the motor is restricted, so that the output torque of the motor can be kept small when starting the shift process as compared with the case where such restriction is not made. Therefore, when starting the shift process to the low gear stage by the transmission in a state where the motor is outputting torque to the rotation output shaft, there are various reasons resulting from the output torque of the motor becoming large. It becomes possible to suppress the occurrence of problems.

  (2) The invention according to claim 2 is the output torque for reducing the output torque of the electric motor to a predetermined value or less in the hybrid power unit according to claim 1 when the shift process based on the shift determination is started. The gist is to further include a reducing means.

  When the output torque of the electric motor is relatively large when starting the shift process to the low gear stage by the transmission while the electric motor is outputting torque to the rotation output shaft, the transmission is configured. There is a problem that a shock when releasing the friction engagement element that is in an engaged state at the start of the shift process among the friction engagement elements becomes large. Therefore, if the output torque of the motor is reduced to a predetermined value or less when starting the shift process, the shock when releasing the friction engagement element in the engaged state can be reduced. become. However, in such a control configuration, when the output torque of the motor is increased during the period from when the shift determination is made until the shift process is started, the output torque of the motor becomes equal to or less than the predetermined value. A long time is required until the start of the shift process is delayed.

  Further, in order to suppress the delay of the start of the shift process in this way, it is conceivable that the output torque of the motor is suddenly reduced to the predetermined value or less when starting the shift process. There arises a new problem that a shock occurs due to the rapid reduction of the output torque.

  In the control device having such a control configuration, if the invention according to claim 1 is applied, an increase in the output torque of the motor is limited during a period from when the shift determination is made until the shift process is started. As a result, the output torque of the electric motor can be kept small when starting the shift process, compared to the case where such a restriction is not made. Therefore, the time required for the output torque of the motor to become the predetermined value or less can be shortened, and the occurrence of a shock due to a delay in the start of the shift process or a sudden decrease in the output torque of the motor can be suppressed accurately. Will be able to.

  (3) According to the first or second aspect of the invention, as in the third aspect of the invention, the hybrid power unit is mounted on a vehicle, and the rotation output shaft is mounted on a drive wheel of the vehicle. The required driving force calculating means for calculating the required driving force of the driving wheel based on the driver's request and the running state of the vehicle, the required driving force of the driving wheel and the output torque of the main power source. Required output torque calculating means for calculating the required output torque of the electric motor based on the above, the output torque limiting means limiting the increase in the required driving force through the required driving force calculating means. It can be embodied in such a manner that the increase in output torque is limited.

  (4) According to a fourth aspect of the present invention, in the hybrid power unit according to the third aspect, the main power source includes an internal combustion engine, and the electric motor outputs torque to the rotation output shaft. When the shift determination to the low gear stage is made by the transmission in a state where the engine is running, if the start process of the internal combustion engine is not completed, the shift process based on the shift determination is completed until the start process is completed The gist of the present invention is to further include a shift process start delay means for delaying the start of the shift.

  When the shift determination to the low gear stage is made by the transmission while the electric motor is outputting torque to the rotation output shaft, the start process is performed if the start process of the internal combustion engine is not completed. There is one that delays the start of shift processing based on the shift determination until completion. In such a control configuration, the output torque of the internal combustion engine does not increase during the period from when the shift determination is made until the start processing of the internal combustion engine is completed. Most of the increase amount is distributed to the increase amount of the required output torque of the electric motor. For this reason, the output torque of the electric motor becomes large when starting the shift process to the low gear stage by the transmission in a state in which the electric motor is outputting torque to the rotation output shaft. Becomes prominent.

  In the control device having such a control configuration, if the invention according to claim 1 is applied, an increase in the output torque of the motor is limited during a period from when the shift determination is made until the shift process is started. For this reason, the output torque of the electric motor can be kept small when starting the shift process, compared to the case where such a restriction is not made. Therefore, when starting the shift process to the low gear stage by the transmission in a state where the motor is outputting torque to the rotation output shaft, there are various reasons resulting from the output torque of the motor becoming large. It becomes possible to suppress the occurrence of problems.

  (5) According to a third or fourth aspect of the present invention, as in the fifth aspect of the present invention, the output torque limiting means limits the increase in the output torque of the motor during the period in which the electric motor is limited. The required output torque is calculated by the output torque calculation means when the shift to the low gear stage is determined by the transmission in a state where the motor is outputting torque to the rotation output shaft. It can be embodied in such a manner that it is limited to a certain value or less.

The schematic block diagram which shows schematic structure of a hybrid power plant about one Embodiment of the hybrid power plant which concerns on this invention. (A) collinear diagram of planetary gear mechanism, (B) collinear diagram of transmission. The map which shows the relationship between a vehicle speed and an accelerator opening degree, and an upshift line and a downshift line. The flowchart which shows the process sequence of the downshift control in the same embodiment. 5 is a timing chart for explaining the operation of the embodiment, in which (a) change in accelerator opening, (b) change in downshift determination, (c) change in start-up process of the internal combustion engine, (d) vehicle FIG. 6 is a timing chart showing a transition of required driving force, (e) transition of required output torque TM2trg of MG2, and (f) transition of shift processing.

Hereinafter, an embodiment in which the present invention is embodied as a hybrid power unit for a vehicle will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a hybrid power unit 2 for a vehicle.

  As shown in the figure, the vehicle hybrid power unit 2 is mounted on a vehicle, and the torque output from the main power source 4 is transmitted to the rotation output shaft 6, and is transmitted from the rotation output shaft 6 through the differential 8. Is transmitted to the driving wheel 10 as a driving force. On the other hand, there is provided a motor generator 12 (hereinafter referred to as “MG2”) which is an assist power source capable of performing power running control for outputting driving force for traveling or regenerative control for recovering energy. MG2 is connected to the rotation output shaft 6 via the transmission 14, and the torque transmitted between the MG2 and the rotation output shaft 6 is increased or decreased according to the gear ratio set by the transmission 14.

  The main power source 4 is composed mainly of an internal combustion engine 16, a motor generator 18 (hereinafter "MG1"), and a planetary gear mechanism 20 that synthesizes or distributes torque between the internal combustion engine 16 and MG1. Yes. The internal combustion engine 16 is a power device such as a gasoline engine or a diesel engine, and is configured to be able to electrically control operation states such as a throttle opening (intake amount), a fuel supply amount, and an ignition timing. The control is performed by an electronic control unit (E-ECU) 22 mainly composed of a microcomputer.

  The MG 1 is a synchronous motor, is configured to have both a function as a motor and a function as a generator, and is connected to a battery 26 via an inverter 24. The torque TM1 (output torque and regenerative torque) of MG1 is set by controlling the inverter 24 through an electronic control unit (MG-ECU) 28 mainly composed of a microcomputer.

  The MG 2 is connected to the battery 26 via the inverter 29. The MG-ECU 28 controls the inverter 29 to control power running and regeneration, and torque TM2 in each case.

  The planetary gear mechanism 20 includes a sun gear 20a, a ring gear 20b arranged concentrically with the sun gear 20a, and a carrier 20c that holds the pinion gear meshing with the sun gear 20a and the ring gear 20b so as to rotate and revolve. Is a gear mechanism that produces a differential action. A rotation output shaft (here, a crankshaft) 16a of the internal combustion engine 16 is connected to a carrier 20c via a damper 16b, whereby the carrier 20c serves as an input element.

  MG1 is connected to the sun gear 20a, and the sun gear 20a is a reaction force element. As a result, the ring gear 20 b serves as an output element and is connected to the rotary output shaft 6. FIG. 2A shows a collinear diagram of the planetary gear mechanism 20 as the above-described torque distribution mechanism (also having a function as a torque synthesizing mechanism). As shown in the figure, a part of the power of the internal combustion engine 16 can be distributed to the rotation output shaft 6 and the other part can be distributed to the MG1.

  The transmission 14 is configured by a set of Ravigneaux planetary gear mechanisms. That is, the first sun gear 14a and the second sun gear 14b are provided, and the short pinion 14c meshes with the first sun gear 14a, and the short pinion 14c and the second sun gear 14b have a longer pinion 14d having a longer axial length. Is engaged. The long pinion 14d meshes with the ring gear 14e disposed concentrically with the sun gears 14a and 14b. Each pinion 14c, 14d is held so as to rotate and revolve by a carrier 14f. Therefore, the first sun gear 14a and the ring gear 14e constitute a mechanism corresponding to a double pinion type planetary gear mechanism together with the respective pinions 14c and 14d, and the second sun gear 14b and the ring gear 14e are a single pinion type together with the long pinion 14d. A mechanism corresponding to the planetary gear mechanism is configured.

  In the transmission 14 having such a configuration, the second sun gear 14b is an input element, the carrier 14f is an output element, and by engaging the first brake B1, a high speed stage High greater than “1” is set, By engaging the second brake B2 in place of the first brake B1, the low speed stage Low having a higher gear ratio than the high speed stage is set. The shift determination for performing the shift process between the respective shift speeds is executed based on the vehicle speed V that is the rotation speed of the rotation output shaft 6 and the accelerator opening ACCP. More specifically, a shift speed region is determined in advance as a map (shift diagram) shown in FIG. 3, and control is performed so that one of the shift speeds is set according to the detected vehicle speed V or accelerator opening ACCP. Is done.

  That is, from the state where the vehicle speed V and the accelerator opening ACCP are in the region on the left side or the upper side of the upshift line indicated by the broken line in the drawing, the region on the right side or the lower side in the drawing from the upshift line. When it is determined that the transition has been made (upshift determination), a process (upshift process) for switching from the low speed stage Low to the high speed stage High is executed. In the upshift process, the second brake B2 that has been engaged in order to establish the low speed stage Low until then is released, and the first brake B1 that has been released is engaged.

  On the other hand, from the state where the vehicle speed V and the accelerator opening ACCP are in the region on the right side or the lower side in the drawing with respect to the downshift line indicated by the alternate long and short dash line in the drawing, When it is determined that the region has been changed (downshift determination), a process (downshift process) for switching from the high speed stage High to the low speed stage Low is executed. In the downshift process, the first brake B1 that has been engaged to establish the high-speed stage High is released, and the second brake B2 that has been released is engaged.

  Shift control including such shift determination and shift processing is performed by an electronic control unit (HV-ECU) 30 having a microcomputer as a main component. The HV-ECU 30 receives a detection result from a sensor that detects the engine operating state and the vehicle traveling state. Examples of such sensors include an accelerator opening sensor 31 that detects an accelerator opening ACCP that is a driver request, an engine rotation speed sensor 16c that detects an engine rotation speed NE that is a rotation speed of the rotation output shaft 16a of the internal combustion engine 16, And a vehicle speed sensor 6a for detecting the rotation speed of the rotation output shaft 6, that is, the vehicle speed V. The E-ECU 22, the MG-ECU 28, and the HV-ECU 30 are connected so as to be able to communicate with each other.

  FIG. 2B is a collinear diagram of the transmission 14. As shown in the figure, when the ring gear 14e is fixed by the second brake B2, the low speed stage Low is set, and the torque output from the MG2 is amplified according to the gear ratio and added to the rotation output shaft 6. If the first sun gear 14a is fixed by the first brake B1, a high speed High having a smaller gear ratio than the low speed Low is set. Since the gear ratio at the high speed stage High is also smaller than “1”, the torque output by the MG 2 is increased according to the gear ratio and applied to the rotation output shaft 6.

In a state where the respective gear stages Low and High are set constantly, the torque applied to the rotation output shaft 6 is a torque obtained by increasing the output torque TM2 of the MG2 in accordance with the gear ratio.
In such a hybrid power unit 2, the required driving force TVtrg of the vehicle is calculated through the HV-ECU 30 based on the traveling state of the vehicle such as the accelerator opening ACCP and the vehicle speed V. In the present embodiment, the sum of the required output torque TRtrg of the main power source 4 and the required output torque TM2trg of the MG2 that is the assist power source is the required drive force TVtrg of the vehicle. The required output torque TM2trg of MG2 is calculated by subtracting the required output torque TRtrg of the power source 4. The HV-ECU 30 in the present embodiment corresponds to the required driving force calculation means and the required output torque calculation means according to the present invention.

  By the way, after the downshift determination is made by the transmission 14 in a state where the MG 2 is outputting torque to the rotation output shaft 6 as in the kickdown shift, the shift process based on the determination is actually started. There may be a time delay. As a cause of such time delay, for example, there is a shift start delay request for starting processing of the internal combustion engine 16 and the like. That is, the shift start delay request for the startup process of the internal combustion engine 16 is issued when the startup process of the internal combustion engine 16 is being executed when the downshift determination is made, and the request is issued. In this case, in order to give priority to the completion of the starting process over the shifting process, the start of the shifting process based on the downshift determination is suspended until the starting process is completed.

  However, there is a time delay from the time when the downshift determination is made in this way until the gear shifting process based on the determination is actually started. During this time delay, the output of MG2 is based on the increase in the accelerator opening ACCP. If the output torque TM2 of the MG2 becomes large when the torque TM2 increases and the shift process is started, it is impossible to avoid various problems resulting from this. That is, when the shift process is started while the output torque TM2 of MG2 is large, the first brake that is engaged until the shift process is started among the plurality of brakes B1 and B2 constituting the transmission 14. The shock when releasing B1 becomes large.

  Therefore, in order to cope with such a problem, it is conceivable to reduce the output torque TM2 of MG2 to a predetermined value T1 or less when the shift process is started. However, in this case, if the output torque TM2 of MG2 increases during the period from when the downshift determination is made until the shift process is started, until the output torque TM2 of MG2 becomes equal to or less than the predetermined value T1. Therefore, it takes a lot of time, and a new problem arises that the start of the shift process is delayed.

  In order to suppress the delay of the start of the shift process in this way, it is conceivable that the output torque TM2 of the MG2 is suddenly reduced to the predetermined value T1 or less when starting the shift process. This causes a new problem that a shock occurs due to a rapid decrease in the output torque TM2.

  Therefore, in the present embodiment, during the period from when the downshift determination is made by the transmission 14 in a state where the MG 2 is outputting torque to the rotation output shaft 6 until the shift process based on the determination is started. The increase in the output torque TM2 of MG2 is limited. As a result, the occurrence of the above-described various problems caused by the output torque TM2 of the MG2 becoming large when the shift process is started is suppressed.

  Specifically, in the period in which the increase in the output torque TM2 of MG2 is limited, the required output torque TM2trg of MG2 is limited to a value calculated when the downshift is determined.

  Hereinafter, with reference to FIG. 4, the processing procedure of the downshift control according to the present embodiment will be described. FIG. 4 is a flowchart showing a processing procedure of the downshift control, and is repeatedly executed at predetermined intervals through the HV-ECU 30 while the HV-ECU 30 is energized.

  As shown in the figure, in this series of processing, it is first determined whether or not there is a downshift determination (step S1). Since the downshift determination is as described with reference to FIG. 3, the description is omitted here. Here, when there is no downshift determination (step S1: “NO”), this series of processing is temporarily ended.

  On the other hand, if there is a downshift determination (step S1: “YES”), it is next determined whether there is a shift process start delay request (step S2). The shift process start delay request is issued when it is necessary to delay the start of the shift process, for example, during execution of the start process of the internal combustion engine 16 described above. Here, when there is a shift process start delay request (step S2: “YES”), next, the required driving force TVtrg of the vehicle is set to a value immediately after the shift process start delay request is issued (step S3). ), This series of processes is temporarily terminated. As a result, for example, in the situation where the required driving force TVtrg of the vehicle increases as the accelerator opening ACCP increases, for example, in the kick down shift, the increase in the required driving force TVtrg is limited. As a result, the increase in the required output torque TM2trg of MG2 is limited.

  On the other hand, when there is no shift process start delay request (step S2: “NO”), it is next determined whether or not the output torque TM2 of MG2 is equal to or less than a predetermined value T1 (step S4). Here, it is determined that the output torque TM2 of MG2 is equal to or lower than the predetermined value T1 when the required output torque TM2trg of MG2 is equal to or lower than the predetermined value T1, but instead, the output torque TM2 of MG2 is determined. It is also possible to provide detection means for directly detecting the above and to make the above determination based on the detection result. As a result, if the output torque TM2 of MG2 is not less than or equal to the predetermined value T1 (step S4: “NO”), in order to reduce the output torque TM2 of MG2, a predetermined output torque TM2trg at that time of MG2 is determined. A value reduced by the value ΔT is set as a new required output torque TM2trg, and this series of processes is temporarily terminated.

  On the other hand, if the output torque TM2 of MG2 is equal to or less than the predetermined value T1 in step S4 (step S4: “YES”), then a shift process is started (step S6), and this series of processes is temporarily performed. finish. Here, when the shift process is started, the first brake B1 that has been engaged in order to establish the high-speed stage High is released, while the second brake B2 that has been released is engaged. This is as described above.

  Next, the operation of this embodiment will be described with reference to the timing chart of FIG. In the figure, it is assumed that the internal combustion engine 16 is stopped before the timing t2.

  As shown in the figure, when the accelerator opening ACCP starts to increase from “0” in response to the driver's request at timing t1 (a), at the subsequent timing t2, the accelerator opening ACCP is greater than or equal to the predetermined opening. As a result, a starting process for starting the internal combustion engine 16 is started (c). Then, at the subsequent timing t3, the accelerator opening ACCP increases and exceeds the downshift line (see FIG. 3 above), and a downshift determination is made (b). However, at this time, since the start process of the internal combustion engine 16 is being executed and a shift process start delay request has been issued, the start of the shift process is suspended at least until timing t4 when the start process is completed. (F)

  In the period (timing t3 to t4) from when the downshift determination is made until the start process of the internal combustion engine 16 is completed, that is, until there is no shift process start delay request, As indicated by the middle broken line, the required driving force TVtrg of the vehicle increases as the accelerator opening ACCP increases (d). At this time, since the internal combustion engine 16 is in the middle of starting and the output torque TR of the internal combustion engine 16 is negligibly small, most of the increase amount of the required driving force TVtrg of the vehicle is increased to the required output torque TM2trg of the MG2. Will be distributed (e). For this reason, when the starting process of the internal combustion engine 16 is completed at timing t4, the required output torque TM2trg of MG2 greatly exceeds the predetermined value T1, and the required output torque TM2trg of MG2 decreases to become equal to or lower than the predetermined value T1. Until this timing t6, the shift process cannot be executed (f).

  On the other hand, according to the hybrid power plant according to the present embodiment, as shown by the solid line in the figure, in the period from the timing t3 when the downshift determination is made to the timing t4 when the shift process start delay request is eliminated, The required driving force TVtrg is maintained at the value at the timing t3 (d). As a result, the required output torque TM2trg of MG2 is also maintained at a value substantially at the timing t3 (e). For this reason, when the starting process of the internal combustion engine 16 is completed at the timing t4, the required output torque TM2trg of the MG2 exceeds the predetermined value T1, but the difference is small. As a result, the timing t5 when the required output torque TM2trg of the MG2 decreases and becomes equal to or less than the predetermined value T1, that is, the timing t6 at which the shift process is executed can be advanced compared to the timing 6 (f).

According to the hybrid power unit according to the present embodiment described above, the following effects can be obtained.
(1) The vehicle hybrid power unit 2 includes a main power source 4 that transmits torque to the rotation output shaft 6 and an MG 2 that transmits torque to the rotation output shaft 6 via the transmission 14. It was. The HV-ECU 30 starts the shift process based on the shift determination after the shift determination to the low gear stage by the transmission 14 in a state where the MG 2 is outputting torque to the rotation output shaft 6. The increase in the output torque TM2 of MG2 is limited during the period up to. As a result, the output torque TM2 of MG2 can be kept small when starting the shift process as compared with the case where such a restriction is not made. Therefore, the output torque TM2 of MG2 becomes large when the shift process to the low gear stage is started by the transmission 14 in a state where MG2 is outputting torque to the rotation output shaft 6. Occurrence of various problems can be suppressed.

  (2) When the shift process based on the shift determination is started, the output torque TM2 of MG2 is reduced to a predetermined value T1 or less. With such a control configuration, since the increase in the output torque TM2 of MG2 is limited during the period from when the shift determination is made until the shift process is started, compared to the case where such a limitation is not made. When starting the shift process, the output torque TM2 of the MG2 can be kept small. Accordingly, the time required for the output torque TM2 of the MG2 to become equal to or less than the predetermined value T1 can be shortened, and the occurrence of a shock due to a delay in the start of the shift process or a sudden decrease in the output torque TM2 of the MG2 can be prevented. It becomes possible to suppress accurately.

  (3) When the start-up process of the internal combustion engine 16 is not completed when the shift to the low gear stage is determined by the transmission 14 with the MG 2 outputting torque to the rotation output shaft 6 The start of the shift process based on the shift determination is delayed until the start process is completed. With such a control configuration, since the increase in the output torque TM2 of MG2 is limited during the period from when the shift determination is made until the shift process is started, compared to the case where such a limitation is not made. When starting the shift process, the output torque TM2 of the MG2 can be kept small. Accordingly, the output torque TM2 of the MG2 becomes large when the shift process to the low gear stage is started by the transmission 14 while the MG2 is outputting torque to the rotation output shaft 6. Occurrence of various problems can be suppressed.

  Note that the hybrid power plant according to the present invention is not limited to the configuration exemplified in the above embodiment, and can be implemented as, for example, the following modes appropriately modified.

  In the above embodiment, in the period (timing t3 to t4) in which the increase in the output torque TM2 of MG2 is restricted, the required output torque TM2trg of MG2 is output in a state where MG2 outputs torque to the rotary output shaft 6. However, the output torque TM2 limiting mode of the MG2 by the output torque limiting means according to the present invention is limited to this. is not. In addition, for example, it may be set to a value smaller than the value when the downshift determination is made by the transmission 14 in a state where MG2 is outputting torque to the rotation output shaft 6 (timing t3). Good. Further, if the value calculated when the output torque is not limited as described above, that is, a value smaller than the value indicated by the broken line in FIG. Thus, it may be set to a value larger than the value when the downshift determination is made by the transmission 14 in a state where the MG2 is outputting torque (timing t3).

  In the above embodiment, when the downshift determination is made, if the start process of the internal combustion engine 16 is not completed, the shift process based on the downshift determination is delayed until the start process is completed. . However, the hybrid power plant according to the present invention is not limited to the one provided with such shift process start delay means. That is, even in a control configuration that does not include such a shift process start delay means, if the output torque according to the present invention is limited, the shift process is started compared to a case where such a limit is not made. Since the output torque TM2 of MG2 can be kept small, the output of MG2 is started when the transmission 14 starts shifting to the low gear stage in a state where MG2 is outputting torque to the rotation output shaft 6. The occurrence of various problems due to the torque TM2 becoming large can be suppressed.

  -In the above-mentioned embodiment, although illustrated about the hybrid power unit mounted in vehicles, the hybrid power unit concerning the present invention is not restricted to this, and it is made to apply the present invention to things other than vehicles. Also good.

  As in the above embodiment, when starting the shift process based on the downshift determination, executing the output torque reduction process that reduces the output torque TM2 of the MG2 to a predetermined value T1 or less is when starting the shift process. In addition, it is desirable to suppress a shock when releasing the frictional engagement element in the engaged state. However, the hybrid power plant according to the present invention is not limited to the one provided with such output torque reducing means. Such processing is performed when the output torque TM2 of MG2 can be kept relatively small through the output torque limiting means. Can be omitted.

  -The structure of a hybrid power unit is not restricted to what was illustrated in the said embodiment. In short, as long as it has a main power source that transmits torque to the rotation output shaft and an electric motor that transmits torque to the rotation output shaft via a transmission, the configuration is appropriately changed to an arbitrary one. Can be changed.

  DESCRIPTION OF SYMBOLS 2 ... Hybrid power unit for vehicles, 4 ... Main power source, 6 ... Rotation output shaft, 6a ... Output shaft rotational speed sensor, 8 ... Differential, 10 ... Drive wheel, 12 ... Motor generator, 14 ... Transmission, 14a ... First 1 sun gear, 14b ... 2nd sun gear, 14c ... short pinion gear, 14d ... long pinion gear, 14e ... ring gear, 14f ... carrier, 16 ... internal combustion engine, 16a ... crankshaft, 16b ... damper, 16c ... engine rotational speed sensor, 18 ... Motor generator, 20 ... planetary gear mechanism, 20a ... sun gear, 20b ... ring gear, 20c ... carrier, 22 ... electronic control unit (E-ECU), 24 ... inverter, 26 ... battery, 28 ... electronic control unit (MG-ECU) , 29... Inverter, 30... Electronic control unit (HV-ECU), B 1. , B2 ... the second brake.

Claims (5)

In a hybrid power unit comprising a main power source that transmits torque to a rotation output shaft, and an electric motor that transmits torque to the rotation output shaft via a transmission,
In a period from when the shift determination to the low shift stage by the transmission is made in a state where the electric motor is outputting torque to the rotation output shaft until the shift process based on the shift determination is started. A hybrid power plant comprising output torque limiting means for limiting an increase in output torque of the electric motor. The hybrid power plant according to claim 1, wherein
The hybrid power plant further comprising: output torque reduction means for reducing the output torque of the electric motor to a predetermined value or less when the shift process based on the shift determination is started. The hybrid power plant according to claim 1 or 2,
The hybrid power unit is mounted on a vehicle, and the rotation output shaft is connected to drive wheels of the vehicle,
Requested driving force calculating means for calculating a required driving force of the driving wheel based on a driver request and a running state of the vehicle;
A required output torque calculating means for calculating a required output torque of the electric motor based on a required driving force of the driving wheel and an output torque of the main power source; and
The output torque limiting means limits an increase in the output torque of the electric motor by limiting an increase in the required driving force through the required driving force calculating means. The hybrid power plant according to claim 3,
The main power source includes an internal combustion engine;
If the internal combustion engine start process is not completed when the shift determination to the low gear stage is made by the transmission while the electric motor is outputting torque to the rotation output shaft. A hybrid power plant further comprising a shift process start delay means for delaying the start of the shift process based on the shift determination until the start process is completed. In the hybrid power plant according to claim 3 or 4,
The output torque limiting means is configured to change the required output torque of the motor during the period in which the increase in the output torque of the motor is limited, while the motor is outputting torque to the rotation output shaft. A hybrid power plant characterized in that when the shift to the low gear stage is determined by the machine, the value is limited to a value calculated by the output torque calculation means.

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