JP2015027854A - Torque controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque controller capable of suppressing discomfort due to accelerating and decelerating even when sufficient torque assist cannot be performed during gear change.SOLUTION: The torque controller of an embodiment comprises: an automatic transmission 16 for switching a torque transmission state and a torque non-transmission state to plural gear pairs having a different gear ratio for performing transmission processing; a clutch 14 for switching a connection state and a cut-off state about drive torque supplied from an internal combustion engine 12 side during transmission processing; a motor generator 18; and a control part 26. The control part 26 is configured to control the motor generator 18 by annealing control so that total torque of the drive torque supplied from the internal combustion engine 12 and the motor torque of the motor generator 18 is annealed by a predetermined annealing ratio with respect to driver request torque from the cut-off state to the connection state, and at latest, until starting of transition of a next cut-off state, when torque control is applied to the motor generator 18 during the transmission processing.

Description

  Embodiments described herein relate generally to a torque control device.

  A vehicle that uses an internal combustion engine as one of the power sources and transmits the power to the drive wheel side via a speed change mechanism needs to temporarily cut off power from the internal combustion engine when performing speed change control. A clutch is provided between the transmission and the speed change mechanism. There are three clutch control states: a connection state in which torque is transmitted, a disconnected state in which torque is not transmitted, and a slip state in which the clutch is in contact while sliding in an intermediate state.

  When the shift control is performed as described above, the power supplied from the internal combustion engine is temporarily interrupted, so that torque is not transmitted to the downstream configuration including the transmission mechanism, so-called “torque loss” occurs. For example, if torque loss occurs during shifting at constant speed or during acceleration, there is a possibility that the vehicle will decelerate against the driving image of the driver, which may cause an uncomfortable feeling. As a countermeasure for this, for example, a technique has been proposed in which the driving torque of the electric motor connected to the output shaft side is increased at the same time as the clutch is disengaged during gear shifting to suppress the vehicle's feeling of deceleration.

Japanese Patent Laid-Open No. 11-69509

However, when performing torque assist by an electric motor as described above, sufficient torque assist is not always possible. In general, an electric motor has a smaller torque that can be output at a high speed than a torque that can be output at a low speed. Therefore, output torque may be limited (torque limit) during high-speed rotation (during high-speed running). Further, torque limitation may be applied even when the amount of charge (SOC) of the battery is insufficient. In such a case, torque loss during shift control may not be sufficiently compensated. Also, after a temporary deceleration feeling is generated due to insufficient torque assist, the shift control is completed and the clutch is engaged, so that the transmission of the engine torque is rapidly resumed to accelerate and give a feeling of acceleration. . That is, unlike the driving image corresponding to the driver's accelerator operation, the vehicle occupant may be more likely to recognize a sense of incongruity than when the vehicle is decelerated in a short time during the shift and a simple feeling of deceleration occurs. In addition, since whether or not the motor can perform sufficient torque assist varies depending on the running state and the state of the SOC, irregular acceleration is generated at the time of a shift, which is more likely to cause a sense of incongruity.
In view of this, it is an object of the present invention to provide a torque control device that can suppress a sense of incongruity (shift shock) due to reduced acceleration even when a vehicle capable of torque assist with a motor at the time of gear shift cannot perform sufficient torque assist at the time of gear shift.

  The torque control device according to the embodiment includes a plurality of gear pairs having different gear ratios between the input shaft and the output shaft, and transmits torque between the input shaft and the output shaft for each gear pair. A transmission mechanism that performs a shift process by switching between a transmission state and a torque non-transmission state that does not transmit torque, and a connection that is connected to the input shaft and that transmits drive torque supplied from the internal combustion engine when performing the shift process A clutch that switches at least between a state and a disconnected state, a motor generator capable of supplying torque to the output shaft side, and a control unit that controls torque of the motor generator, wherein the control unit includes the shift process If the motor generator output torque is limited at the time of The total torque of the driving torque supplied from the internal combustion engine and the motor torque supplied from the motor generator before starting the transition to the next disconnected state at the latest after the operation is based on the accelerator operation amount operated by the driver The motor generator is controlled to be smoothed at a predetermined smoothing rate with respect to the driver required torque. According to this aspect, when the output of the motor generator is limited during the shift process, the total torque is smoothed even when the clutch is connected at least in the shift process and torque transmission from the internal combustion engine side is restored. Shift shock can be reduced.

  In addition, the control unit of the torque control device according to the embodiment may correct the annealing rate in accordance with the magnitude of the driver request torque. The driver request torque changes as the driver changes the amount of operation of the accelerator pedal. That is, it corresponds to the driving image of the driver. Therefore, by correcting the smoothing rate according to the driver request torque, torque control corresponding to the driving image can be performed, and the driver's uncomfortable feeling can be reduced.

  In addition, the control unit of the torque control device according to the embodiment may generate the negative torque by regeneratively controlling the motor generator during the smoothing control so as to make the total torque. According to this aspect, the total torque can be adjusted by offsetting a part of the drive torque provided from the internal combustion engine with the negative torque generated by the regenerative control. In addition, since the electric power generated by the regenerative control can be used when the torque of the motor generator is required next time, the torque shortage of the motor generator can be reduced.

  Further, the control unit of the torque control device according to the embodiment may correct the driver required torque and execute the smoothing control within the output possible range of the motor generator. According to this aspect, since the torque control is performed within the output possible range of the motor generator, it is possible to prevent a contradiction in the control due to a torque shortage with respect to the driver request torque.

  In addition, the smoothing rate in the torque control device according to the embodiment may be changed according to the type of the gear pair that is in the torque transmission state after the shift by the transmission mechanism. The optimum number of revolutions is determined for each gear pair. The motor generator determines the torque that can be output according to the rotational speed. Therefore, by changing the smoothing rate in accordance with the gear ratio after the shift, the uncomfortable feeling of torque fluctuation can be reduced.

FIG. 1 is a functional block diagram of a hybrid vehicle including a torque control device according to the embodiment. FIG. 2 is a schematic diagram of a drive system centered on a drive train of a hybrid vehicle including the torque control device according to the embodiment. FIG. 3 is a diagram showing a comparative example showing a change in torque when torque is not limited by the motor generator when torque loss occurs during gear shifting and sufficient torque assist can be performed. FIG. 4 is a diagram showing a comparative example showing a torque change when torque is limited by the motor generator when torque loss occurs at the time of shifting and sufficient torque assist cannot be performed. FIG. 5 is a flowchart illustrating torque control processing of the torque control device according to the embodiment. FIG. 6 is a diagram illustrating a torque change when the torque control process of the torque control device according to the embodiment is executed. FIG. 7 is a functional block diagram of a hybrid vehicle having another configuration including the torque control device according to the embodiment. FIG. 8 is a schematic diagram showing a modification of the drive system centering on the drive train of the hybrid vehicle including the torque control device according to the embodiment.

  FIG. 1 is a functional block diagram of a hybrid vehicle including a torque control device according to the present embodiment. The torque control device according to the present embodiment supplies torque from a motor generator to generate torque when the clutch is disengaged during transmission control of the transmission mechanism and torque from the internal combustion engine is not temporarily transmitted to the transmission mechanism side. compensate. At that time, if the output torque of the motor generator is less than the driver required torque requested by the driver, the internal combustion engine until the clutch starts transitioning from the disconnected state to the next disconnected state at the latest through the connected state. The total torque of the drive torque supplied from the motor and the motor torque supplied from the motor generator is controlled. Specifically, the motor generator is controlled so that the total torque is smoothed at a predetermined smoothing rate with respect to the driver request torque based on the accelerator operation amount operated by the driver.

  A hybrid vehicle 10 shown in FIG. 1 includes an internal combustion engine 12, a clutch 14, an automatic transmission 16, a motor generator 18, an inverter 20, a battery 22, a differential device (differential) 24, a control unit 26, a storage unit 28, and the like. ing. In FIG. 1, configurations that are not related to the present embodiment are omitted.

  The internal combustion engine 12 is, for example, a gasoline engine, and the engine speed and engine torque are controlled by the control unit 26. The clutch 14 is disposed between the output shaft of the internal combustion engine 12 and the input shaft of the automatic transmission 16. The clutch 14 is in contact with the clutch 14 while slipping in a connected state in which power (rotational force or torque) supplied from the internal combustion engine 12 side is transmitted, a disconnected state in which the power is not transmitted, and an intermediate state between the connected state and the disconnected state. There are three states of sliding state. The control state of the clutch 14 is also controlled by the control unit 26 according to the traveling state.

  Although the automatic transmission (transmission mechanism) 16 can be a dog transmission including a so-called dog clutch described later, in another embodiment, the transmission may include a synchromesh. A motor generator 18 is connected to the output shaft side of the automatic transmission 16. In the configuration of FIG. 1, a switching mechanism 30 is provided between the motor generator 18 and the output shaft of the automatic transmission 16. The switching mechanism 30 can select the case where the motor generator 18 is directly connected to the output shaft side of the automatic transmission 16 and the case where the motor generator 18 is separated from the output shaft side of the automatic transmission 16. When the motor generator 18 is directly connected to the output shaft side, the output torque of the motor generator 18 that functions as a motor can be provided to the differential device 24 side by receiving power supply from the battery 22 via the inverter 20. Therefore, when the driving force is not supplied from the internal combustion engine 12, EV traveling using only the motor generator 18 as a driving source is possible. Further, in the case where the driving force is supplied from the internal combustion engine 12, an assist travel that assists the driving force of the internal combustion engine 12 is possible. In addition, when the hybrid vehicle 10 is braked, the motor generator 18 can function as a generator, and the battery 22 can be charged via the inverter 20. If the motor generator 18 is separated from the automatic transmission 16 side by the switching mechanism 30, only the internal combustion engine 12 can run.

  The differential device 24 absorbs a speed difference (difference in the number of revolutions) generated in the inner and outer wheels 32 when the hybrid vehicle 10 makes a turn, and from a power source (the internal combustion engine 12 and / or the motor generator 18). Torque is distributed to each wheel 32 and transmitted.

  The control unit 26 controls the internal combustion engine 12, the clutch 14, the automatic transmission 16, the inverter 20, the battery 22, and the like in accordance with a driving request based on a driving operation of the driver or a driving state of the hybrid vehicle 10, so Realize driving. In the case of the configuration of FIG. 1, the control unit 26 is shown as an integrated control unit that performs integrated control of each device. However, the control unit 26 is provided with an individual control unit for each control target so that each control unit is cooperatively controlled. Also good. Also, some functions may be controlled collectively. The storage unit 28 stores various information acquired by the control unit 26. In addition, the stored information is provided to the control unit 26 to control each device or reflect it in feedback control of each device. Note that the control unit 26 may process the information to create new information or update existing information based on the acquired various types of information and store the new information in the storage unit 28.

  FIG. 2 is a schematic diagram of a drive system centering on the drive train of the hybrid vehicle 10. For example, a dry clutch 14 is disposed between the input shaft 16 a of the automatic transmission 16 and the crankshaft 12 a of the internal combustion engine 12.

  The clutch 14 includes a flywheel, a clutch disk, a pressure plate, a diaphragm spring, a clutch cover, a clutch control mechanism, and the like. Due to the urging force of the diaphragm spring, the clutch disc and the pressure plate, and the flywheel and the clutch disc come into contact with each other to generate a frictional force. Due to this frictional force, a connection state in which power is transmitted via the clutch 14 between the crankshaft 12a and the input shaft 16a is established. The clutch control mechanism adjusts the degree of contact of the clutch 14 and includes a hydraulic actuator. By increasing the hydraulic pressure of the hydraulic actuator, the pressing force with which the diaphragm spring presses the pressure plate is reduced, and the contact between the clutch disk and the pressure plate, and the flywheel and the clutch disk is released. As a result, the clutch 14 shifts to a disconnected state through a sliding state.

  The connected state is a state in which the flywheel and the clutch disk are in contact with each other and rotate integrally at the same rotational speed. The sliding state is a state in which the flywheel and the clutch disk are in contact with each other and rotate at different rotational speeds. The disconnected state is a state where the flywheel and the clutch disc are disconnected and no power is transmitted. The actuator can control the degree of power transmission in the slipping state of the clutch 14.

  The maximum torque that can be transmitted in the clutch 14, that is, the torque capacity of the clutch 14 changes according to the magnitude of the pressing force with which the diaphragm spring presses the pressure plate. In the following description, the maximum torque that can be transmitted in the clutch 14 is referred to as “clutch torque”. The clutch torque can be controlled by adjusting the clutch stroke by the hydraulic pressure control of the hydraulic actuator.

  The input shaft 16a that is spline-fitted with the clutch disk of the clutch 14 includes a plurality of drive gears that constitute a plurality of gear pairs. In the example shown in FIG. 2, the first speed drive gear 56a, the second speed drive gear 56b, and the reverse drive gear 56f are fixed to the input shaft 16a and are configured to rotate integrally. On the other hand, the third speed drive gear 56c, the fourth speed drive gear 56d, and the fifth speed drive gear 56e are rotatably supported by the input shaft 16a.

  A first dog clutch 58 is provided between the third speed drive gear 56c and the fourth speed drive gear 56d. The first dog clutch 58 has a ring-shaped sleeve 58b that can be moved in the axial direction by spline fitting to the outer peripheral surface of the hub 58a fixed to the input shaft 16a. On one side of the hub 58a, a clutch ring 58c that is concentrically fixed to the third speed drive gear 56c and is rotatable with respect to the input shaft 16a is provided. On the other side, a clutch ring 58c fixed concentrically to the fourth speed drive gear 56d and rotatable with respect to the input shaft 16a is provided. In the clutch ring 58c, dog teeth in which the spline of the sleeve 58b meshes with the side surface facing the hub 58a are arranged in the circumferential direction. Therefore, when the sleeve 58b moves on the hub 58a toward the clutch ring 58c on the third speed drive gear 56c side and the spline and dog teeth mesh with each other, the third speed drive gear 56c is fixed to the input shaft 16a. Thus, it rotates integrally and enters a torque transmission state.

  Similarly, when the sleeve 58b moves on the hub 58a toward the clutch ring 58c on the fourth speed drive gear 56d side and the spline and dog teeth mesh with each other, the fourth speed drive gear 56d is brought into contact with the input shaft 16a. It is fixed and rotates as a unit to enter a torque transmission state. On the other hand, since the clutch ring 58c on the side where the spline and the dog teeth do not mesh with each other maintains the state of being rotatable with respect to the input shaft 16a, the drive gear integrated with the clutch ring 58c is also rotatable with respect to the input shaft 16a. State is maintained. That is, a torque non-transmission state is established. When the sleeve 58b exists at the neutral position on the hub 58a, the third speed drive gear 56c and the fourth speed drive gear 56d are both in a torque non-transmitting state.

  A second dog clutch 60 is provided in the fifth speed drive gear 56e. The second dog clutch 60 has a clutch ring 60c on one side of the hub 60a so as to switch between a torque transmission state and a torque non-transmission state of the fifth speed drive gear 56e, and is configured to mesh with the sleeve 60b. The configuration is the same as that of the 1 dog clutch 58.

  The output shaft 16b of the automatic transmission 16 includes a first speed driven gear 62a to a fifth speed driven gear 62e corresponding to a first speed drive gear 56a to a fifth speed drive gear 56e and a reverse drive gear 56f. A reverse driven gear 62f is provided. The third speed driven gear 62c to the fifth speed driven gear 62e are fixed to the output shaft 16b, and a third dog clutch 64 is provided between the first speed driven gear 62a and the second speed driven gear 62b. Yes. The third dog clutch 64 has the same configuration as that of the first dog clutch 58. Depending on the operating state of the third dog clutch 64, torque transmission between the first speed driven gear 62a and the second speed driven gear 62b to the output shaft 16b is performed. Switch between state and torque non-transmission state. The third dog clutch 64 can also be controlled to a neutral state in which the first speed driven gear 62a and the second speed driven gear 62b are in a torque non-transmitting state.

  A reverse driven gear 62f is fixed to the outer peripheral surface of the sleeve 64b of the third dog clutch 64. During reverse travel, the reverse idler 66 is inserted between the reverse drive gear 56f and the reverse drive gear 62f. When the input shaft 16a is rotated in the rotational direction during forward travel, the hub 64a that is spline-fitted with the sleeve 64b rotates in the opposite direction (reverse direction) to forward travel. Since the hub 64a is fixed to the output shaft 16b, the output shaft 16b rotates in the reverse direction. The reverse idler 66 may be configured to switch between a torque transmission state during reverse travel and a torque non-transmission state in other cases by a dog clutch.

  An output gear 70 that meshes with the ring gear 68 of the differential device 24 is fixed to the output shaft 16b. The first speed drive gear 56a to the fifth speed drive gear 56e and the reverse drive gear 56f mesh with the first speed driven gear 62a to the fifth speed driven gear 62e and the reverse drive gear 62f, respectively. A gear pair 72, a second gear pair 74, a third gear pair 76, a fourth gear pair 78, a fifth gear pair 80, and a reverse gear pair 82 are configured. When the hybrid vehicle 10 is driven using the power of the internal combustion engine 12, the control unit 26 moves the dog clutch sleeve so that any one of the gear pairs is in a torque transmitting state, and moves from the input shaft 16a to the output shaft 16b. Transmit torque.

  2 shows an example in which the switching mechanism 30 in FIG. 1 is omitted and the motor generator 18 is directly connected to the differential device 24. That is, the drive gear 18 b is fixed to the output shaft 18 a of the motor generator 18 and meshes with the driven gear 84 a fixed to the counter shaft 84. A pinion gear 84 b is fixed to the counter shaft 84 and meshes with the ring gear 68. Therefore, when the hybrid vehicle 10 is driven only by the driving force of the motor generator 18, the dog clutches may be controlled so that the gear pairs on the automatic transmission 16 side are all in the neutral state. Further, since the motor generator 18 is directly connected to the differential device 24, the motor generator 18 becomes a load when torque assist by the motor generator 18 is not required. In such a case, the motor generator 18 may generate a torque for canceling the load. In the case of the example in FIG. 2, a parking gear 86 is fixed to the counter shaft 84. When the parking state is set by operating the shift lever or the like, the countershaft 84 and the ring gear 68 become non-rotatable and the wheels are locked by engaging the locking claw operated by an actuator (not shown) and the parking gear 86. That is, a parking state can be realized.

  When the traveling control of the hybrid vehicle 10 configured as described above is performed, a shift process is performed in which a gear pair that is in a transmission state is selected and switched appropriately in the automatic transmission 16 according to the traveling state. When executing the shift process, the control unit 26 disconnects the torque from the internal combustion engine 12 temporarily by disengaging the clutch 14 prior to the shift process. At the same time, the torque of the internal combustion engine 12 is reduced in order to prevent the internal combustion engine 12 from blowing up. At this time, the control unit 26 tries to perform torque control so as to satisfy the driver requested torque based on the accelerator operation amount operated by the driver, but the clutch 14 shifts from the connected state to the disconnected state through the slipping state. Therefore, the engine torque input to the input shaft 16a of the automatic transmission 16 gradually decreases and becomes “0” when the clutch 14 is disengaged. That is, the torque output from the output shaft 16b of the automatic transmission 16 is gradually reduced to a so-called “torque loss” state, which causes a feeling of deceleration. Therefore, the control unit 26 controls the motor generator 18 to supply motor torque to the output shaft 16 b of the automatic transmission 16. In this case, the motor torque to be supplied is gradually increased in correspondence with the gradual decrease of the engine torque so that the total torque of the engine torque and the motor torque becomes the driver required torque. When the clutch 14 is in a disengaged state, the motor torque of the motor generator 18 covers all of the driver request torque. Thereafter, when the gear pair after the shift in the automatic transmission 16 is in the torque transmission state, the control unit 26 shifts the clutch 14 from the disconnected state to the connected state through the sliding state. That is, the control unit 26 starts to gradually increase the engine torque, while starting to gradually decrease the motor torque. When the clutch 14 completely shifts to the connected state, the motor torque becomes “0”, and the engine torque covers all of the driver request torque. By performing such torque control, shift control without “torque loss” can be realized.

  FIG. 3 is a comparative example schematically showing a torque change when the motor torque output from the motor generator 18 described above can completely cover the decrease in the engine torque, that is, when the torque assist can be sufficiently performed. In FIG. 3 and FIGS. 4 and 6 to be described later, the driver request torque a is indicated by a solid line, and the engine torque b is indicated by a broken line. Further, the motor torque c is indicated by a one-dot chain line, and the total torque d is indicated by a two-dot chain line. 3, 4, and 6, the gear pair that is switched by the automatic transmission 16 at the time of shifting, that is, the required required gear stage r is indicated by a broken line, and the actual gear stage that is actually shifted s is indicated by a solid line. 3, 4, and 6, the case of shifting from “first speed” to “second speed” is shown as an example. 3, 4, and 6, in order to facilitate identification of each line, a portion where two or more lines overlap is drawn with the lines slightly shifted, but it is assumed that they are basically overlapping.

  In the case of FIG. 3, the time point at which the shift process is started is indicated as a reference (0 seconds). The control unit 26 shifts the clutch 14 to the slipping state when the shift process is started. At this time, the required gear stage r is changed to the second speed. Then, for example, in “0.5 seconds”, the clutch 14 is disengaged. The control unit 26 gradually reduces the engine torque of the internal combustion engine 12 at the timing when the clutch 14 is shifted to the slipping state, thereby preventing the blow-up. At the same time, the motor torque of the motor generator 18 is gradually increased to compensate for the reduced torque. When the clutch 14 is disengaged, the automatic transmission 16 shifts to the neutral state after the actual gear stage s is in the indeterminate state from the first speed, that is, in a state where the gears such as the first speed and the second speed are not determined or neutral (N). Then, the vehicle shifts to the second speed through an indefinite state. During “0.5 seconds” to “1.5 seconds” when the clutch 14 is disengaged, the driver request torque a is all covered by the motor torque c. Thereafter, the control unit 26 makes the clutch 14 in a slipping state, for example, at “1.5 seconds”, and starts a transition to the connected state. That is, the automatic transmission 16 completes the switching of the gear pair while the clutch 14 is completely disconnected. Even when the accelerator operation amount operated by the driver is constant, when the gear position of the automatic transmission 16 shifts from “1st speed” to “2nd speed”, the driver required torque is determined according to the gear ratio of the corresponding gear pair. a decreases (around 1.5 seconds). When the clutch 14 shifts to the slipping state, the transmission of the engine torque b is resumed, and the gradual increase of the engine torque b is started. Correspondingly, the gradual increase of the motor torque c is started. As a result of the speed change (shift up), the driver request torque a decreases according to the gear ratio, so the total torque d due to the gradual increase of the engine torque b and the gradual decrease of the motor torque c satisfies the changed driver request torque a. To be adjusted. For example, in “2.0 seconds”, the clutch 14 is completely connected, and the shift process is completed. That is, the state returns to a state where all of the driver request torque a is covered by the engine torque b. During this series of shift processing, the total torque d is the same as the driver request torque a, indicating that no “torque loss” has occurred.

  FIG. 4 is a diagram showing a comparative example when the motor torque output from the motor generator 18 cannot satisfy the driver request torque during the shift process of the automatic transmission 16. The reason why the motor generator 18 cannot output sufficient motor torque may be due to the characteristics of the motor generator 18 itself. Generally, an electric motor has a smaller motor torque that can be output at a high speed than a motor torque that can be output at a low speed. Therefore, when the speed change control is executed during high-speed rotation (during high-speed running) and the driver request torque must be covered by the motor torque of the motor generator 18, the necessary motor torque may not be produced. That is, output torque may be limited (torque limitation). Further, as another case where a sufficient motor torque cannot be output, the charge amount (SOC) of the battery 22 may be insufficient. In this case, torque limitation may be applied. In the case of FIG. 4, the motor generator 18 can temporarily output a motor torque c of, for example, 175 Nm, but an example is shown in which torque limitation is maximized in the vicinity of, for example, 120 Nm due to insufficient charging of the battery 22.

  In FIG. 4, as in FIG. 3, the control unit 26 starts to gradually decrease the engine torque b when starting the shift process, and starts to gradually increase the motor torque c accordingly. When the clutch 14 is completely disengaged (0.5 seconds), the driver request torque a is covered only by the motor torque c. However, in the example of FIG. 4, torque limitation is applied in the middle due to insufficient charge amount of the battery 22, and the motor torque c is reduced (around 1.0 seconds in FIG. 4). In the figure, the clutch 14 is disengaged from “0.5 seconds” to “1.5 seconds”, and the engine torque b is not transmitted. Therefore, the total torque d decreases in the same manner as the motor torque c.

  Then, the control unit 26 controls the clutch 14 to be in a slipping state when the change of the gear pair is completed in the automatic transmission 16 and gradually increases the engine torque b (after 1.5 seconds). Therefore, the total torque d that has decreased due to “torque loss” starts to increase rapidly when the clutch 14 shifts to the slipping state and the engine torque b starts to recover rapidly (1. in FIG. 4). After 5 seconds). That is, the torque transmitted to the output shaft 16b decreases rapidly and then increases rapidly. As a result, during shifting, deceleration and acceleration as indicated by the region M are continued in a short time, which may give the driver and the passenger a sense of discomfort. In this case, since it suddenly changes to acceleration after deceleration, it is easily recognized as a shift shock G.

On the other hand, in the hybrid vehicle 10 equipped with the torque control device of this embodiment, the shift shock is not easily recognized.
FIG. 5 is a flowchart illustrating a control process in the torque control device of the present embodiment. FIG. 6 is a diagram showing a state of torque fluctuation when the control according to the flowchart of FIG. 5 is executed when the motor generator 18 cannot generate sufficient motor torque at the time of shifting.

  First, the control unit 26 detects whether or not a shift process is started by the automatic transmission 16 during traveling (N in S100). For example, based on the vehicle speed and the degree of depression of the accelerator pedal, the shift map is referred to determine whether it is the timing for shifting. If it is determined that it is time to start shifting (Y in S100), the control unit 26 performs control to shift the clutch 14 to the disengaged state, and gradually decreases the engine torque b and gradually increases the motor torque c. Then, the control is switched to the control that covers the driver request torque a during the shift process with the motor torque c (for example, 0 to 0.5 seconds). The controller 26 determines whether or not the motor generator 18 is in a torque limit state when the motor torque c covers the driver request torque a. Specifically, the required motor torque (required MG torque) required to satisfy the driver required torque is compared with the actual motor torque (actual MG torque) that can actually be output. If the required MG torque-actual MG torque> threshold value 1 (for example, threshold value = 0) (Y in S102), it is determined that the torque limit is applied, and the control unit 26 turns on the MG torque limit flag (S104). ). In addition, since transmission of various information including the information for this comparison is performed via a vehicle-mounted network, it is necessary to consider information transmission time and information processing time. Therefore, it is desirable that the determination of “requested MG torque−actual MG torque> threshold value 1” be made after waiting for a predetermined time to elapse after it is determined that it is the timing to start shifting. During the period N during which the gear pair is switched, the clutch 14 is disengaged, so the engine torque b is not transmitted and the total torque d is covered only by the motor torque c. If requested MG torque−actual MG torque> threshold 1 is not satisfied (N in S102), that is, if the motor torque c has a margin, S104 is skipped. In this case, the torque is in the state shown in FIG. 3, and no shift shock is generated.

Here, the required MG torque at the time of shifting varies depending on the state of the automatic transmission 16 and the clutch 14 and the state of the engine torque and the clutch torque at that time.
For example, consider a case where the actual shift position (actual shift P) of the automatic transmission 16 is not in the neutral state (N) and the clutch 14 is not in the disengaged state (actual shift P ≠ N and clutch ≠ disengaged). At this time, when the magnitude of the clutch torque is equal to or larger than the absolute value of the engine torque (in the case of clutch torque ≧ | engine torque |), that is, when the clutch 14 is completely connected while the hybrid vehicle 10 is running, the request The MG torque is “driver required torque−engine torque”.

  On the other hand, in the case of clutch torque <| engine torque |, that is, when the clutch 14 is in a slipping state and engine torque ≧ 0, the required MG torque is “driver required torque−clutch torque”. When engine torque <0, the required MG torque is “driver required torque + clutch torque”.

  When the actual shift s of the automatic transmission 16 is in a neutral state (N) or when the clutch 14 is in a disengaged state, that is, when the automatic transmission 16 is not completely transmitting torque, the required MG torque is The same as the required torque.

  Then, the control unit 26 determines whether or not the gear pair has been switched in the automatic transmission 16, that is, the actual shift position (actual shift P) at the requested shift position (required gear stage r: the gear pair to be switched). ) Are matched based on, for example, the state of the dog clutch actuator (S106). If the required shift P is not equal to the actual shift P, that is, if the gear pair is being switched, the process proceeds to S102 to determine whether or not a new torque limit is applied (N in S106). For example, in the previous process, sufficient torque assist is possible, and even if the driver request torque a can be covered by the motor torque c, the SOC may be reduced and the torque may be limited during the gear pair switching. .

  When required shift P = actual shift P (Y in S106), that is, when the MG torque limit flag is not ON (N in S108) when the gear pair switching is completed, that is, sufficient torque If the assist has been made, this flow is once ended.

  On the other hand, when the switching of the gear pair is completed, the MG torque limit flag is ON (Y in S108), that is, the driver request torque a cannot be covered only by the motor torque c. . In this case, if the clutch 14 is connected in this state and the transmission of the engine torque b is resumed, there is a possibility that a shift shock G will occur as shown in FIG. Therefore, in the present embodiment, the motor generator 18 is controlled so that the total torque d is smoothed with respect to the driver request torque a at a predetermined smoothing rate. In other words, the shift shock is made difficult to appear by “stuning” the total torque d so that the total torque d does not increase suddenly when the supply of the engine torque b is resumed. In the case of the present embodiment, by correcting the driver request torque, the motor torque is corrected as a result and the total torque is smoothed (S110). In the present embodiment, “smoothing control” refers to executing torque control so that the total torque is increased with a gentler slope than the slope (increase) of the total torque d after the occurrence of the shift shock G in FIG. means.

  In this smoothing control, the required shift P = actual shift P is established, and thereafter, the clutch 14 is activated at a timing (point A) at which the clutch 14 is only shifted from the disconnected state to the connected state. At the time of point A, the clutch 14 is in a disengaged state, so the driver request torque should be equal to the motor torque. However, as shown in FIG. 6, since the motor torque c is insufficient, the driver requested torque a is corrected from the point A as indicated by a thick line so that the smoothing control can be executed within the output possible range of the motor generator 18. (Corrected driver required torque e).

  Here, the correction of the corrected driver request torque e can be obtained by adding a reference rate value (predetermined predetermined value) to the driver request torque at the previous calculation. In another embodiment, the driver required torque at the time of the previous calculation + the reference rate value × (current accelerator pedal depression amount / accelerator pedal depression amount at the time of the previous correction process). For example, when the driver requests to accelerate by stepping on the accelerator at the time of shifting, the rate value to be added is increased compared to the case where the driver does not step on the accelerator. This is based on the fact that when the driver requests acceleration, he / she is driving with a sense of acceleration, so even if the acceleration after deceleration due to “torque loss” is large to some extent, it is difficult to feel uncomfortable. is there. In addition, by increasing the rate value to generate a feeling of acceleration, another effect can be obtained that it is easy to give a feeling that a quick shift has been performed.

  The reference rate value may be calculated by, for example, (post-shift driver request torque-pre-shift driver request torque) / target time. As described above, even if the accelerator operation amount is the same, the driver required torque changes when the gear stage (gear ratio of each gear pair) of the automatic transmission 16 changes. Therefore, the driver requested torque after the shift, in the case of FIG. 6, the increase rate value per unit time is determined so that the torque suitable for traveling at “second speed” is reached. It is desirable that the driver request torque reaches a torque suitable for the current gear stage at least before the start of the next shift process. In other words, it is desirable that the smoothing process is completed and the driver requested torque is reached by the time the clutch 14 starts moving from the disconnected state to the next disconnected state at the latest through the connected state. FIG. 6 shows an example in which the smoothing control is completed in 1.5 seconds from 1.5 seconds to 3.0 seconds, and the next shift process can be executed after 3.0 seconds. Therefore, in the example of FIG. 6, the target time is 1.5 seconds.

  Incidentally, in the case of the present embodiment, the engine torque b is controlled according to the selected gear stage (gear ratio). Therefore, when the driver request torque a is corrected by the smoothing control to obtain the corrected driver request torque e, As a result, the motor torque c is corrected. That is, the control unit 26 cancels out the portion of the engine torque b that exceeds the corrected driver request torque e by causing the motor generator 18 to function as an electric motor and generating negative torque. When the motor generator 18 functions as an electric motor, the regenerative energy generated at that time can be charged to the battery 22. As a result, the regenerative energy collected this time can be used for torque assist executed at the next shift. That is, the “smoothing control” during the current control has the effect of reducing the “shift shock” during the current control and reducing or suppressing the “torque loss” during the next control.

  Then, the control unit 26 waits for the corrected driver request torque e to become the driver request torque (N in S112). When the correction driver request torque becomes equal to the driver request torque (Y in S112), the control unit 26 turns ON in the current shift process. The current MG torque limit flag is reset (S114), and the shift process from “1st speed” to “2nd speed” is terminated. If it is determined in S112 that the corrected driver request torque is not equal to the driver request torque (N in S112), the process returns to S110 and the driver request torque correction process is repeated.

  As described above, according to the torque control device of the present embodiment, when the motor generator 18 is limited in output during the shift process, the clutch 14 is connected at least in the shift process, and the torque transmission from the internal combustion engine 12 side is restored. Since the total torque is smoothed even when doing, the shift shock can be reduced. In the above-described embodiment, the case where “torque loss” occurs due to a shortage of SOC has been described. However, even when “torque loss” occurs due to the performance of the motor generator 18, the same effect is obtained by smoothing control. be able to.

  FIG. 7 is a functional block diagram of a hybrid vehicle having another configuration including the torque control device according to the present embodiment. The basic configuration is the same as that of the hybrid vehicle 10 shown in FIG. 1, and the same reference numerals are given to the same configurations, and the description thereof is omitted. In the case of the configuration of FIG. 7, a switching mechanism 30 a that switches connection / disconnection between the motor generator 18 and the output shaft side of the automatic transmission 16, and connection / disconnection between the motor generator 18 and the input shaft side of the automatic transmission 16. And a switching mechanism 30b for switching between. In this case, the motor generator 18 realizes the function of preventing torque loss during control of the clutch 14 as described above by setting the switching mechanism 30a to the connected state. Further, the motor generator 18 can be used as a drive source or a generator depending on the traveling state of the hybrid vehicle 10, and the efficient hybrid vehicle 10 can be used while reducing torque loss. Can be realized. When the automatic transmission 16 is in the neutral state, the clutch 14 is in the connected state, and the motor generator 18 is connected to the input shaft of the automatic transmission 16 by the switching mechanism 30b, the crankshaft of the stopped internal combustion engine 12 is rotated. be able to. That is, the starter device for the internal combustion engine 12 can be omitted, and the configuration can be simplified and the cost can be reduced. Further, the input shaft of the automatic transmission 16 can be rotated during the shift process, that is, when the clutch 14 is in a disconnected state. As a result, rotation speed synchronization when switching the gear pair of the automatic transmission 16 using the dog clutch is facilitated, and smooth shift processing can be realized. In another embodiment, separate motor generators may be arranged on the input shaft side and the output shaft side of the automatic transmission 16. Since only the rotation synchronization function and the starter function described above may be provided on the input shaft side, a motor having no generator function may be provided on the input shaft side.

  FIG. 8 shows an example in which the switching mechanisms 30a and 30b of FIG. Also in the case of FIG. 8, the same components as those in FIG. The connection switching unit 88 is constituted by, for example, a dog clutch, and when the motor generator 18 is connected to the input shaft 16a, when connected to the output shaft 16b, or when neutral is not connected to any of the input shaft 16a and the output shaft 16b. There is. In FIG. 8, the automatic transmission 16 has the same structure and the same function as the automatic transmission 16 shown in FIG. 2, but the illustration is simplified. Basically, the torque of the internal combustion engine 12 transmitted to the input shaft 16a of the automatic transmission 16 via the clutch 14 is transmitted to the output shaft 16b side via a plurality of gear pairs. A dog clutch that switches torque transmission is not shown. When the drive gear 18b fixed to the output shaft 18a of the motor generator 18 meshes with the switching gear 88a on the input shaft 16a side, the connection switching unit 88 transmits the torque of the motor generator 18 to the input shaft 16a. Therefore, when the clutch 14 is connected and the torque of the internal combustion engine 12 is input to the input shaft 16a, the motor assist travel is performed. Further, when the clutch 14 is disengaged, only the motor travels. On the other hand, when the drive gear 18b meshes with the switching gear 88b, the torque of the motor generator 18 is transmitted to the second gear 90b fixed to the output shaft 16b via the first gear 90a. Therefore, when the clutch 14 is connected and the torque of the internal combustion engine 12 is input to the input shaft 16a, the motor assist travel is performed. Further, when the clutch 14 is disengaged, only the motor travels. When the drive gear 18b does not mesh with either the switching gear 88a or the switching gear 88b, the engine travels only with the torque of the internal combustion engine 12 due to the connection of the clutch 14. 8 can also rotate the crankshaft of the internal combustion engine 12 with the motor generator 18, and the starter device can be omitted, contributing to simplification of the configuration and cost reduction. can do. Then, the connection switching unit 88 reduces the “torque loss” at the time of shifting as in the above-described embodiment, regardless of whether the motor generator 18 is connected to the input shaft 16a side or the output shaft 16b side. In addition, “smoothing control” can be implemented, and the same effect can be obtained.

  In the present embodiment, the dog transmission including the dog clutch is shown as the configuration of the automatic transmission 16, but the automatic transmission 16 can be applied to a clutch including the synchromesh.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 12 ... Internal combustion engine, 14 ... Clutch, 16 ... Automatic transmission, 16a ... Input shaft, 16b ... Output shaft, 18 ... Motor generator, 18a ... Output shaft, 26 ... Control part.

Claims (5)

A plurality of gear pairs having different gear ratios are provided between the input shaft and the output shaft, a torque transmission state for transmitting torque between the input shaft and the output shaft for each gear pair, and a torque non-transmitting torque. A transmission mechanism that performs transmission processing by switching between transmission states;
A clutch that is connected to the input shaft and at least switches between a connected state for transmitting a driving torque supplied from the internal combustion engine side when performing the shift process and a disconnected state for blocking;
A motor generator capable of supplying torque to the output shaft side;
A control unit for controlling the torque of the motor generator;
With
When the output of the motor generator is limited during the speed change process, the control unit waits until the clutch starts transitioning from the disconnected state to the next disconnected state through the connected state at the latest. Further, the total torque of the drive torque supplied from the internal combustion engine and the motor torque supplied from the motor generator is smoothed at a predetermined smoothing rate with respect to the driver request torque based on the accelerator operation amount operated by the driver. A torque control device for controlling the motor generator.   The torque control device according to claim 1, wherein the control unit corrects the smoothing rate in accordance with a magnitude of the driver request torque.   3. The torque control device according to claim 1, wherein the control unit generates the negative torque by performing regenerative control of the motor generator during the smoothing control to generate the total torque.   4. The torque control device according to claim 1, wherein the control unit corrects the driver request torque and executes smoothing control within an output possible range of the motor generator. 5.   5. The torque control device according to claim 1, wherein the smoothing rate is changed according to the gear pair that is in a torque transmission state after a shift by the transmission mechanism.

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