Vehicle control device, vehicle control method, and program

Abstract

[PROBLEM] To provide a configuration in which it is possible to reduce fluctuations in output torque when changing speed and to alleviate acceleration / deceleration fluctuations felt by a driver. [Solution] Provided is a control device for a vehicle that includes: a motor; and an automatic transmission which is connected downstream of the motor. The control device for a vehicle includes a control unit that gradually reduces the torque of the motor and then gradually increases the engagement capacity of engagement-side engagement elements of the automatic transmission and the torque of the motor.

Description

Vehicle control device, vehicle control method, and program

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a program.

[0002] Patent Document 1 discloses a technique for suppressing fluctuations in output torque by increasing motor torque during gear changes.

[0003] Japanese Patent Application Publication No. 5-319144

[0004] Motors have an upper limit on output depending on their rotational speed, and depending on the rotational state of the motor, even if you try to suppress fluctuations in output torque (wheel acceleration / deceleration) by increasing the motor torque, there may not be enough margin (margin for torque increase) to completely suppress the fluctuations or to suppress them to an acceptable level.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a configuration that can reduce fluctuations in output torque during gear changes and alleviate fluctuations in acceleration and deceleration that the driver feels.

[0006] According to one aspect of the present invention, there is provided a control device for a vehicle having a motor and an automatic transmission connected downstream of the motor, the control device having a control unit that gradually reduces the torque of the motor and then gradually increases the engagement capacity of the engagement side engagement element of the automatic transmission and the torque of the motor.

[0007] According to this aspect, by gradually increasing the motor torque in conjunction with a gradual increase in the engagement capacity of the engagement-side frictional element, it is possible to suppress a decrease in output torque during gear shifting. Also, by gradually reducing the motor torque in advance just before gradually increasing the motor torque, it is possible to increase the amount of torque increase during the gradual increase in motor torque, thereby reducing fluctuations in output torque during gear shifting and mitigating fluctuations in acceleration / deceleration that the driver feels.

[0008] FIG. 1 is a schematic diagram showing the main parts of a vehicle. FIG. 2 is an explanatory diagram of acceleration / deceleration fluctuations that occur in a vehicle when changing gears. FIG. 3 is an explanatory diagram of torque cooperative control. FIG. 4 is a diagram showing an example of a map. FIG. 5 is a flowchart showing an example of control performed by a controller. FIG. 6 is an explanatory diagram of motor torque gradual reduction control. FIG. 7 is a diagram showing an example of a timing chart corresponding to FIG. 5. FIG. 8 is a diagram showing an example of a timing chart of a comparative example.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] Fig. 1 is a schematic diagram showing the main parts of a vehicle 1. Fig. 1 shows a motor 10 and an automatic transmission 20 in a skeleton diagram in which the lower half of the drawing below the center of rotation is omitted.

[0011] Vehicle 1 includes a motor 10, an automatic transmission 20, an inverter 30, and a controller 50. Motor 10 constitutes the drive source of vehicle 1, and power from motor 10 is transmitted to drive wheels via automatic transmission 20. Power from motor 10 can be transmitted from automatic transmission 20 to the drive wheels via a reducer that reduces and outputs the input rotation from automatic transmission 20, and a differential mechanism that distributes power from the reducer to the left and right drive wheels of vehicle 1.

[0012] The motor 10 is a rotating electric machine and is a three-phase AC motor. The motor 10 is driven by power supplied from an inverter 30 that converts DC power from a battery into AC power. The motor 10 has a rotor 11, a stator 12 that houses the rotor 11, and a motor shaft 13 that rotates integrally with the rotor 11. The stator 12 is fixed to the inner periphery of a housing, and the motor shaft 13 is connected to a rotating shaft 21 of the automatic transmission 20. The motor shaft 13 may also serve as the rotating shaft 21 of the automatic transmission 20.

[0013] The automatic transmission 20 is a stepped automatic transmission and includes, in addition to a rotating shaft 21, a planetary gear mechanism PGM, a brake B as an engagement element, a clutch CL as an engagement element, and a housing 22 that accommodates the planetary gear mechanism PGM, the brake B, and the clutch CL. The planetary gear mechanism PGM is provided within the housing 22 via the brake B. The housing 22 may be configured as a common housing with the motor 10, or may be a housing separate from the motor 10. Rotation from the motor 10 is input to the planetary gear mechanism PGM via the rotating shaft 21.

[0014] The planetary gear mechanism PGM includes a sun gear S, a carrier C, a ring gear R, and a pinion gear P. The sun gear S rotates integrally with the rotary shaft 21, and the carrier C rotatably supports the pinion gear P, which meshes with both the sun gear S and the ring gear R. The ring gear R meshes with the pinion gear P via internal teeth.

[0015] The brake B is provided to be able to connect and disconnect the ring gear R and the housing 22, and the clutch CL is provided to be able to connect and disconnect the carrier C and the rotating shaft 21 (sun gear S). The brake B and the clutch CL are electromagnetic clutches whose engagement capacity can be controlled in accordance with a control current. The brake B and the clutch CL may also be frictional engagement elements (e.g., hydraulic clutches).

[0016] When the brake B is in an engaged state and the clutch CL is in a disengaged state, the first gear is achieved, and the input rotation from the motor 10 is transmitted to the carrier C via the sun gear S and the pinion gear P. The carrier C is an output element of the planetary gear mechanism PGM, and the rotation transmitted to the carrier C is transmitted to the drive wheels.

[0017] When the brake B is released and the clutch CL is engaged, the second gear is achieved, and the carrier C rotates integrally with the rotating shaft 21 (sun gear S) connected integrally by the clutch CL. Therefore, the second gear ratio (the value obtained by dividing the input rotation speed by the output rotation speed) is set to 1. The second gear ratio is set smaller than the first gear ratio.

[0018] The vehicle 1 further includes a controller 50. The controller 50 is a vehicle control device that performs control by executing a program stored in a ROM or RAM using a CPU. The program may be stored in a non-transitory storage medium such as a CD-ROM. The controller 50 is composed of one or more computers (microcomputers) equipped with a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 50 may be composed of multiple controllers.

[0019] Signals necessary for controlling the vehicle 1, such as signals from an accelerator opening sensor 61 for detecting the accelerator opening APO and a vehicle speed sensor 62 for detecting the vehicle speed VSP, are input to the controller 50, and the controller 50 is programmed to control the vehicle 1 based on the input signals.

[0020] When controlling the motor 10, the controller 50 controls the inverter 30 based on an input signal, thereby controlling the motor 10. The motor 10 is controlled by applying three-phase AC generated by the inverter 30 based on a command from the controller 50.

[0021] When controlling the automatic transmission 20, the controller 50 controls the brake B and the clutch CL based on input signals. In the automatic transmission 20, the engagement capacities of the brake B and the clutch CL are controlled based on commands (control currents) from the controller 50.

[0022] When the automatic transmission 20 is shifting gears, the output torque Td (torque at the drive wheels) of the vehicle 1 may fluctuate, causing fluctuations in acceleration and deceleration, as will be explained below.

[0023] 2 is an explanatory diagram of fluctuations in acceleration and deceleration that occur in the vehicle 1 during gear changes. Fig. 2 shows the changes in various parameters during an upshift from first gear to second gear. During an upshift, the clutch CL serves as the engagement-side engagement element, and the brake B serves as the release-side engagement element. In this example, the motor torque Tmot is constant.

[0024] At timing T1, a gear shift is initiated, and the engagement capacity of the clutch CL begins to increase (gradually increase). From timing T1, torque is transferred from the brake B to the clutch CL. During the torque transfer, the engagement capacity of the brake B, which was engaged in first gear, is gradually decreased, and the engagement capacity of the clutch CL, which was disengaged in first gear, is gradually increased. As a result, the automatic transmission 20 performs an upshift without passing through a neutral state. During the torque transfer, the sum of the engagement capacities of the brake B and the clutch CL is maintained at the motor torque Tmot.

[0025] Between timings T1 and T2, torque switching progresses. The period between timings T1 and T2 is the torque phase, during which the motor rotation speed Nmot remains roughly constant while the output torque Td changes. The output torque Td gradually decreases (fluctuations) according to the inter-stage ratio before and after the gear shift (the inter-stage ratio between first and second gears).

[0026] At timing T2, the brake B is released, and the system transitions from the torque phase to the inertia phase. From timing T2, the motor rotation speed Nmot (the input rotation speed of the automatic transmission 20) changes toward the output rotation speed Nout of the automatic transmission 20 due to a change in the inertia of the power transmission system connecting the motor 10 and the drive wheels.

[0027] At this time, the output torque Td fluctuates in the increasing direction due to changes in the inertial force of the power transmission system, causing fluctuations in acceleration and deceleration. The fluctuations in output torque Td occur from time T2 to time T3, and between times T2 and T3 the engagement capacity of the clutch CL increases or decreases in accordance with the fluctuations in output torque Td. The inertia phase ends at time T3, and the motor rotation speed Nmot becomes the output rotation speed Nout at time T3.

[0028] In a vehicle 1 that uses a motor 10 as a drive source, which has high responsiveness to fluctuations in output torque Td generated in this manner, fluctuations in output torque Td (acceleration / deceleration fluctuations) can be suppressed by performing the torque cooperative control described below.

[0029] 3 is an explanatory diagram of torque cooperative control. In torque cooperative control, motor torque Tmot is controlled so as to suppress fluctuations in output torque Td. In this example, torque cooperative control gradually increases motor torque Tmot in the torque phase between timings T1 and T2. Motor torque Tmot is gradually increased in accordance with the inter-stage ratio before and after the gear shift, and at timing T2, when the system transitions to the inertia phase, it is gradually increased to a value greater than that at timing T1 by an amount corresponding to the inter-stage ratio before and after the gear shift.

[0030] By gradually increasing motor torque Tmot in this manner, it is possible to suppress fluctuations in output torque Td during the torque phase (see the interval between times T1 and T2 in FIG. 2). During the torque phase, torque transfer proceeds while maintaining the sum of the transmission capacities of brake B and clutch CL at the gradually increasing motor torque Tmot. As a result, at time T2, the transmission capacity of clutch CL becomes motor torque Tmot, which is greater than that at time T1 by an amount corresponding to the gear ratio before and after the shift.

[0031] During the inertia phase between timings T2 and T3, the motor torque Tmot is reduced by torque cooperative control. The motor torque Tmot is reduced by an amount that completely suppresses the fluctuation of the output torque Td during the inertia phase (see timings T2 and T3 in FIG. 2 ), depending on the magnitude of the fluctuation.

[0032] During the inertia phase, the motor torque Tmot is quickly reduced from time T2 by an amount sufficient to completely suppress the fluctuations, and then maintained at the reduced magnitude. The motor torque Tmot is also quickly increased immediately before time T3, when the inertia phase ends, and returns to the original motor torque Tmot (motor torque Tmot at time T2) at time T3.

[0033] By reducing the motor torque Tmot compared to times T2 and T3 in this way, it is possible to completely suppress fluctuations in the output torque Td during the inertia phase (see the interval between times T2 and T3 in Figure 2). During the inertia phase, the transmission capacity of the clutch CL required after the gear shift has already been obtained at time T2, so the transmission capacity of the clutch CL remains unchanged.

[0034] In this example, the motor 10 has enough capacity (margin for the increase in the motor torque Tmot) to completely suppress fluctuations in the output torque Td, so torque cooperative control makes it possible to completely suppress the output torque Td.

[0035] On the other hand, the motor 10 has an upper limit on output according to the motor rotation speed Nmot, and depending on the rotation state of the motor 10, even if an attempt is made to suppress fluctuations in the output torque Td by increasing the motor torque Tmot, there may not be enough capacity to completely suppress the fluctuations or to suppress them to an acceptable level.

[0036] Next, this point will be explained using the map shown in Fig. 4. Hereinafter, the margin of increase in the motor torque Tmot will be simply referred to as the margin of torque increase.

[0037] Fig. 4 is a diagram showing an example of a map. The driving force F on the vertical axis represents the driving force of the vehicle 1 (driving force at the drive wheels). Fig. 4 shows, as examples of maximum driving force characteristics (lines representing characteristics) FL for each accelerator opening APO according to the vehicle speed VSP, a maximum driving force characteristic FL1 when the accelerator opening APO is 8 / 8 (i.e., fully open), a maximum driving force characteristic FL2 when the accelerator opening APO is 7 / 8, and a maximum driving force characteristic FL3 when the accelerator opening APO is 6 / 8. The first maximum vehicle speed VSP1 represents the maximum value of the vehicle speed VSP in first gear, and the second maximum vehicle speed VSP2 represents the maximum value of the vehicle speed VSP in second gear.

[0038] As shown in Figure 4, the maximum driving force for each accelerator opening APO increases as the accelerator opening APO increases, assuming the vehicle speed VSP is the same. Furthermore, due to the characteristics of the motor 10, the maximum driving force for each accelerator opening APO remains roughly constant when the vehicle speed VSP is less than a predetermined vehicle speed VSP3, but decreases as the vehicle speed VSP increases when the vehicle speed VSP is equal to or greater than the predetermined vehicle speed VSP3. The predetermined vehicle speed VSP3 is determined by the characteristics of the motor 10 and is lower than the first maximum vehicle speed VSP1.

[0039] The first maximum vehicle speed VSP1 and the second maximum vehicle speed VSP2 are determined according to the gear ratio of the automatic transmission 20. For example, if the motor rotation speed Nmot becomes the maximum motor rotation speed when the vehicle is traveling in first gear, the vehicle speed VSP becomes the first maximum vehicle speed VSP1 corresponding to the gear ratio of first gear. In this case, in order to obtain a vehicle speed VSP higher than the first maximum vehicle speed VSP1, it is necessary to shift the automatic transmission 20 from first gear to second gear.

[0040] For this reason, a shift line SL for instructing a gear change is set in advance in the map according to the vehicle speed VSP and the driving force F. The shift line SL is an upshift line for instructing an upshift, and is set in advance in an area equal to or less than the first maximum vehicle speed VSP1. The upshift line is set so as to intersect with the maximum driving force characteristic FL (e.g., maximum driving force characteristics FL1 to FL3) when the accelerator opening APO is large, near the first maximum vehicle speed VSP1.

[0041] When the operating point W on the map passes the shift line SL from the low vehicle speed side (left side in Figure 4) to the high vehicle speed side (right side in Figure 4), an upshift command is input from the controller 50 to the automatic transmission 20, and the engagement capacities of the brake B and clutch CL are controlled based on the upshift command.

[0042] In the maximum driving force characteristic FL1, when the vehicle speed VSP is the first maximum vehicle speed VSP1, the maximum driving force becomes driving force F1 (operating point W1), and in order to accelerate from operating point W1, an upshift must be performed.

[0043] However, at operating point W1, the accelerator opening APO is fully open and the maximum driving force is being generated, so the motor torque Tmot cannot be increased further, and the motor 10 does not have the capacity (margin for torque increase) to increase the motor torque Tmot.

[0044] Therefore, in this case, it is not possible to suppress the fluctuations in the output torque Td as described above with reference to FIG. 2 by increasing the motor torque Tmot through torque cooperative control.

[0045] On the other hand, the margin for torque increase increases as the accelerator opening APO decreases. Therefore, the larger the area on the map expands in the direction in which the accelerator opening APO decreases from the operating point W1, the larger the margin for torque increase becomes, and by expanding this area, a margin for torque increase sufficient to completely suppress fluctuations in the output torque Td can be obtained.

[0046] Regions R1 and R2 are regions (region R1) where motor 10 does not have sufficient reserve power (margin for torque increase) to completely suppress fluctuations in output torque Td during upshifting, and regions (region R2) where it does. Figure 4 shows regions R1 and R2 obtained by expanding the region with upper limits of vehicle speed VSP and driving force F corresponding to operating point W1 from operating point W1 in the direction in which accelerator opening APO decreases along maximum driving force characteristic FL.

[0047] Next, the control performed by the controller 50 will be described.

[0048] 5 is a flowchart showing an example of control performed by the controller 50. By executing the process of this flowchart, the controller 50 functions as a control unit that executes the process (i.e., has a control unit that executes the process).

[0049] In step S1, it is determined whether the accelerator pedal position APO is equal to or greater than a predetermined position α and whether the operating point W is within region R1. The predetermined position α is a preset value used to determine whether the accelerator pedal position APO is high, i.e., whether there is no margin for torque increase (see regions R1 and R2 in FIG. 4). The driving force F that defines the operating point W can be calculated based on the motor torque Tmot, etc., and the vehicle speed VSP that defines the operating point W can be detected based on a signal from the vehicle speed sensor 62.

[0050] If the determination in step S1 is negative, it is determined that there is a margin for torque increase, and the process proceeds to step S2. In step S2, it is determined whether an upshift is to be performed. Whether an upshift is to be performed can be determined based on a map.

[0051] If the determination in step S2 is negative, the process is temporarily terminated. If the determination in step S2 is positive, the process proceeds to step S3 and then step S4. The processes in steps S3 and S4 are performed during an upshift, with step S3 being performed in the torque phase and step S4 being performed in the inertia phase.

[0052] In step S3, the clutch CL is engaged and the motor torque Tmot is increased (see the interval between timings T1 and T2 in FIG. 3). This suppresses fluctuations in the output torque Td during the torque phase (see the interval between timings T1 and T2 in FIG. 2). In step S3, the engagement capacity of the clutch CL and the motor torque Tmot are gradually increased. Furthermore, in step S3, torque switching is performed, so that the engagement capacity of the clutch CL is gradually increased and the engagement capacity of the brake B is gradually decreased.

[0053] In step S4, the motor torque Tmot is decreased, and then increased again (see timings T2 and T3 in FIG. 3), thereby suppressing fluctuations in the output torque Td during the inertia phase (see the interval between timings T2 and T3 in FIG. 2).

[0054] If the determination in step S1 is negative, there is a margin for torque increase that is sufficient to suppress fluctuations in the output torque Td, and therefore, in this case, by performing the processes in steps S3 and S4, fluctuations in the output torque Td can be suppressed (see output torque Td in FIG. 3).

[0055] If the determination in step S1 is affirmative, it is determined that the accelerator opening APO is large, the operating point W is within region R1, and there is no margin for torque increase, and the process proceeds to step S5. In step S5, the motor torque Tmot is gradually decreased. The motor torque Tmot is gradually decreased as follows.

[0056] Fig. 6 is an explanatory diagram of the gradual decrease control of the motor torque Tmot. Fig. 6 illustrates the gradual decrease control of the motor torque Tmot, taking the accelerator opening APO at 8 / 8 as an example. The maximum driving force characteristic FL indicated by the dashed line represents the maximum driving force characteristic FL when the gradual decrease control of the motor torque Tmot is not performed.

[0057] As shown in FIG. 6, when the vehicle speed VSP is equal to or higher than a predetermined vehicle speed VSP4, the maximum driving force characteristic FL is gradually decreased (gradual decrease line GDL) so that the maximum driving force (and therefore the motor torque Tmot) becomes smaller as the vehicle speed VSP increases.

[0058] The predetermined vehicle speed VSP4 is the vehicle speed at which the motor torque Tmot begins to decrease, and can be set in advance to a vehicle speed VSP lower than the shift vehicle speed VSP5 for each accelerator pedal position APO. The shift vehicle speed VSP5 is the vehicle speed VSP corresponding to the intersection of the maximum driving force characteristic FL and the shift line SL, and can be determined for each accelerator pedal position APO. The motor torque Tmot may be gradually decreased based on the maximum driving force characteristic FL, which is shown by a solid line on the map as a gradual decrease line GDL, or may be gradually decreased by calculation based on the maximum driving force characteristic FL, which is shown by a dashed line, as shown by the gradual decrease line GDL.

[0059] 5, after step S5, the process proceeds to step S2, and if the determination in step S2 is affirmative, the process proceeds to step S3 and then to step S4. In this case, since there is no margin for torque increase, in step S3, the motor torque Tmot is gradually increased to the maximum motor torque Tmot_max.

[0060] Furthermore, in step S4, the engagement capacity of the clutch CL is gradually increased. This is because, if there is no margin for torque increase, the motor torque Tmot has not been increased to the torque that is originally intended to be output in the torque phase, and therefore the engagement capacity of the clutch CL has not been increased to the engagement capacity that is originally intended to be output. After step S4, the process temporarily ends.

[0061] In this embodiment, in step S1, it is determined that there is no margin for torque increase, provided that the operating point W is within region R1. However, it is also possible to determine in step S1 that there is no margin for torque increase, and to perform gradual reduction control of motor torque Tmot, without providing that the operating point W is within region R1, provided that the accelerator opening APO is equal to or greater than a predetermined opening α.

[0062] In step S1, it may be determined whether the accelerator opening APO is equal to or greater than a predetermined opening α and the vehicle speed VSP is equal to or greater than a predetermined vehicle speed, thereby determining whether the accelerator opening APO is equal to or greater than the predetermined opening α and whether the operating point W is within region R1. The controller 50 may perform gradual reduction control of the motor torque Tmot when the accelerator opening APO is equal to or greater than the predetermined opening α and the vehicle speed VSP is equal to or greater than the predetermined vehicle speed. The predetermined vehicle speed may be set in advance as a value that defines region R1 together with the accelerator opening APO (a threshold value of the vehicle speed VSP set according to the driving force F). The predetermined vehicle speed may also be set as a fixed value (a fixed threshold value) rather than as a vehicle speed VSP (variable value) set according to the driving force F. Note that setting the predetermined vehicle speed to the vehicle speed VSP (variable value) set according to the driving force F is preferable because it increases the frequency of execution of control that significantly suppresses acceleration / deceleration fluctuations as shown in FIG. 3 . When the vehicle speed VSP (variable value) is set according to the driving force F, the value of the predetermined vehicle speed is set to be smaller as the driving force F increases. This is because the greater the driving force F, the less margin there is in the motor torque Tmot.

[0063] Fig. 7 is a diagram showing an example of a timing chart corresponding to the flowchart shown in Fig. 5, and corresponds to a case where there is no margin for torque increase and gradual reduction control of motor torque Tmot is performed. Fig. 8 is a diagram showing an example of a timing chart of a comparative example, and shows a case where there is no margin for torque increase but gradual reduction control of motor torque Tmot is not performed.

[0064] 7, in this example, the motor torque Tmot begins to decrease at time T0, which is before time T1 when the upshift is initiated, due to the gradual reduction control of the motor torque Tmot. The gradual reduction of the motor torque Tmot continues until time T1 when the upshift is initiated. The same is true for the output torque Td, and the engagement capacity of the brake B is gradually reduced in accordance with the gradual reduction of the motor torque Tmot.

[0065] Between times T1 and T2, torque is transferred between the brake B and the clutch CL, the engagement capacity of the clutch CL is increased, and the motor torque Tmot is increased to suppress the decrease in the output torque Td generated in the torque phase (see between times T1 and T2 in Figure 2).

[0066] The motor torque Tmot and the engagement capacity of the clutch CL shown by the dashed lines are the motor torque and engagement capacity required to completely suppress fluctuations in the output torque Td, that is, the motor torque and engagement capacity that are originally desired to be output, and the motor torque Tmot shown by the dashed line exceeds the maximum motor torque Tmot_max slightly before timing T2. In other words, in this example, there is not enough torque increase capacity to completely suppress fluctuations in the output torque Td.

[0067] Therefore, in this example, the motor torque Tmot is gradually increased so as to reach the maximum motor torque Tmot_max at timing T2, and the slope (rate of increase) of the motor torque Tmot is gentler than the motor torque indicated by the dashed line. The same applies to the engagement capacity of the clutch CL.

[0068] In this way, even if it is not possible to completely suppress the fluctuations in the output torque Td, it is possible to suppress the fluctuations in the output torque Td as much as possible.

[0069] In the comparative example shown in Figure 8, the motor torque Tmot and the engagement capacity of the clutch CL are also gradually increased between times T1 and T2. However, in the comparative example, the motor torque Tmot is not gradually decreased before time T1, so the torque increase ΔTmot2 of the motor torque Tmot between times T1 and T2 is smaller than the torque increase ΔTmot1 of the motor torque Tmot between times T1 and T2 shown in Figure 7.

[0070] In other words, in the case of the present embodiment shown in Figure 7, by performing a gradual decrease control of the motor torque Tmot, the motor torque Tmot is reduced in advance just before the motor torque Tmot is gradually increased, so that the torque increase amount ΔTmot1 from timing T1 to timing T2 when the upshift is initiated can be made larger than the torque increase amount ΔTmot2 in the comparative example.

[0071] As a result, the fluctuation amount ΔTd1 of the output torque Td between the timings T1 and T2 can be made smaller than the fluctuation amount ΔTd2 of the output torque Td in the comparative example (see FIG. 8), so that the fluctuation of the output torque Td during gear changes can be reduced and the acceleration / deceleration fluctuation felt by the driver can be alleviated. The acceleration / deceleration fluctuation felt by the driver is also alleviated by the gradual slope (degree of change) of the output torque Td between the timings T1 and T2.

[0072] At time T2, the torque capacity of the clutch CL becomes the motor torque Tmot, and the brake B is released. During the inertia phase between times T2 and T3, the torque capacity of the clutch CL gradually increases, and the motor rotation speed Nmot decreases. At time T3, the torque capacity of the clutch CL becomes the desired torque capacity, as indicated by the dashed line.

[0073] On the other hand, from time T2 onwards, in order to suppress the influence of the inertia torque of the motor 10 that occurs at this time, the motor torque Tmot is reduced. During the inertia phase, the motor torque Tmot is reduced so as to vary in a region lower than the imaginary line VL connecting the motor torque Tmot at times T2 and T3. During the inertia phase, the motor torque Tmot varies as follows:

[0074] That is, in the inertia phase, motor torque Tmot is rapidly reduced from time T2 and then immediately gradually increased, with motor torque Tmot gradually increasing in accordance with the change in maximum motor torque Tmot_max. Thereafter, motor torque Tmot is rapidly increased immediately before time T3 so that output torque Td at time T3 becomes the original output torque Td1 (output torque Td immediately before time T0) before the gradual reduction control of motor torque Tmot was executed. Therefore, motor torque Tmot is set so that output torque Td becomes the original output torque Td1 at time T3.

[0075] In the inertia phase after the brake B is released, the motor torque Tmot is reduced while the engagement capacity of the clutch CL is gradually increased, thereby reducing the influence of the inertia torque of the motor 10 that occurs when the motor rotation speed Nmot decreases due to the engagement of the clutch CL. This reduces fluctuations in the output torque Td and alleviates fluctuations in acceleration and deceleration that the driver feels.

[0076] Next, the main effects of the controller 50 will be described.

[0077] (1) The controller 50 is a control device for a vehicle having a motor 10 and an automatic transmission 20 connected downstream of the motor 10, and gradually reduces the motor torque Tmot of the motor 10 and then gradually increases the engagement capacity of the clutch CL of the automatic transmission 20 and the motor torque Tmot of the motor 10.

[0078] With this configuration, by gradually increasing motor torque Tmot along with the gradual increase in the transmission capacity of clutch CL, it is possible to suppress a decrease in output torque Td during an upshift. Also, by gradually decreasing motor torque Tmot in advance just before gradually increasing motor torque Tmot, it is possible to increase the amount of torque increase during the gradual increase of motor torque Tmot (see torque increase amount ΔTmot1 in FIG. 7), which reduces fluctuations in output torque Td during an upshift and alleviates fluctuations in acceleration / deceleration felt by the driver.

[0079] (2) When the accelerator opening APO is less than the predetermined opening α, the controller 50 does not execute the control to gradually decrease the motor torque Tmot before gradually increasing the engagement capacity of the clutch CL and the motor torque Tmot, i.e., the control to gradually decrease the motor torque Tmot (see step S5 in Figure 5).

[0080] With this configuration, when the accelerator opening APO is less than the predetermined opening α, the difference between the motor torque Tmot at the start of the upshift and the maximum motor torque Tmot_max is large, and there is room to increase the amount and slope of increase in motor torque Tmot, so there is no need to perform gradual reduction control of motor torque Tmot.This eliminates minute fluctuations in output torque Td caused by the gradual reduction in motor torque Tmot before the upshift, and further mitigates fluctuations in acceleration and deceleration at low openings.

[0081] (3) The controller 50 gradually decreases the engagement capacity of the brake B of the automatic transmission 20 while gradually increasing the engagement capacity of the clutch CL, and after the brake B is released, decreases the motor torque Tmot while gradually increasing the engagement capacity of the clutch CL.

[0082] According to this configuration, in the inertia phase after the brake B is released, in order to suppress the influence of the inertia torque of the motor 10 that occurs when the motor rotation speed Nmot decreases due to the engagement of the clutch CL, the motor torque Tmot is reduced, thereby reducing fluctuations in the output torque Td and mitigating the acceleration / deceleration fluctuations felt by the driver.

[0083] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0084] For example, the automatic transmission 20 may be a multi-speed transmission having two or more gears.

[0085] 1: Vehicle 10: Motor 20: Automatic transmission 50: Controller (vehicle control device, control unit) APO: Accelerator opening B: Brake (releasing side engaging element) CL: Clutch (engaging side engaging element) Tmot: Motor torque α: Predetermined opening

Claims

1. A control device for a vehicle having a motor and an automatic transmission connected downstream of the motor, the control device having a control unit that gradually reduces the torque of the motor and then gradually increases the engagement capacity of an engagement-side engagement element of the automatic transmission and the torque of the motor.

2. A vehicle control device as described in claim 1, wherein the control unit does not execute control to gradually decrease the engagement capacity of the engagement side friction element and the torque of the motor before gradually increasing the torque of the motor when the accelerator opening is less than a predetermined opening.

3. A vehicle control device as described in claim 1, wherein the control unit gradually decreases the engagement capacity of the disengagement side engagement element of the automatic transmission while gradually increasing the engagement capacity of the engagement side engagement element, and after the disengagement side engagement element is released, decreases the torque of the motor while gradually increasing the engagement capacity of the engagement side engagement element.

4. A method for controlling a vehicle having a motor and an automatic transmission connected downstream of the motor, comprising gradually reducing the torque of the motor and then gradually increasing the torque of the motor and the engagement capacity of an engagement-side engagement element of the automatic transmission.

5. A program executable by a computer in a control device for a vehicle having a motor and an automatic transmission connected downstream of the motor, the program including gradually reducing the torque of the motor and then gradually increasing the torque of the motor and the engagement capacity of the engagement side engagement element of the automatic transmission.

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