Vehicle control device

Abstract

The invention provides a vehicle control device. The decrease rate of the drive torque when the requested value of the drive torque decreases is set to a larger value as the amount of change in the accelerator operation amount from the time when the accelerator return operation is performed to the current time increases. As a result, when the amount of change in the accelerator operation amount is relatively large, it is easy to become a scene in which responsiveness is desired to be emphasized, and therefore, the reduction rate of the drive torque is set to a relatively large value, and therefore, it is possible to quickly reduce the drive torque. On the other hand, when the amount of change in the accelerator operation amount is relatively small, it is easy to attempt to pay attention to controllability, and therefore, the reduction rate of the drive torque is set to a relatively small value, making it possible to gently reduce the drive torque.

Description

Technical Field

[0001] The present invention relates to a vehicle control device for setting a reduction rate of drive torque when reducing a requested value of the drive torque. Background Art

[0002] Control devices for vehicles equipped with a power source and a power transmission device that transmits power from the power source to drive wheels are well known. For example, the vehicle described in Japanese Patent Application Laid-Open No. 2009-137384 is one such control device. Japanese Patent Application Laid-Open No. 2009-137384 discloses that, when the accelerator is switched from on to off, a reduction rate for the driving torque is set such that the greater the range from the current battery charge to the input limit, the greater the reduction rate of the driving torque. Summary of the Invention

[0003] Here, depending on the accelerator operation amount at the time of the accelerator return operation, or the accelerator operation amount at the current moment after the accelerator return operation, there may be different scenarios such as a scenario where responsiveness is desired or a scenario where controllability is desired. The accelerator return operation is an accelerator operation state that changes from an increasing state to a decreasing state. Responsiveness is a deceleration characteristic that causes the driving torque to decrease rapidly in response to the accelerator return operation. Controllability is a deceleration characteristic that causes the driving torque to decrease smoothly in response to the accelerator return operation. However, in the technology described in Japanese Patent Application Laid-Open No. 2009-137384, when the accelerator return operation is performed, the reduction rate of the driving torque is set according to the input limit of the battery, and a uniform reduction rate of the driving torque is set regardless of whether the accelerator operation amount is different. Therefore, if the reduction rate of the driving torque is set in a manner corresponding to the scenario where responsiveness is desired, controllability may be deteriorated. Alternatively, if the reduction rate of the driving torque is set in a manner corresponding to the scenario where controllability is desired, responsiveness may be deteriorated.

[0004] The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle control device capable of setting a reduction rate of driving torque according to different scenarios of responsiveness and controllability.

[0005] The gist of the first invention is, (a) a control device for a vehicle including a power source and a power transmission device for transmitting power from the power source to drive wheels, (b) including a drive control unit configured to set a larger value for a reduction rate of the drive torque when decreasing toward a requested drive torque value based on a current value of the accelerator operation amount as a change in the accelerator operation amount from a time when an accelerator return operation is performed to a current time, wherein the accelerator return operation is an operation in which the accelerator operation state changes from an increasing state to a decreasing state.

[0006] According to the first invention, the greater the change in the accelerator operation amount from the moment the accelerator return operation is performed to the current moment, the greater the reduction rate of the driving torque when the requested value of the driving torque is reduced. In this way, when the change in the accelerator operation amount is relatively large, it is likely that the scenario is to emphasize responsiveness. In this case, the reduction rate of the driving torque is set to a relatively large value, thereby enabling the driving torque to be reduced rapidly. On the other hand, when the change in the accelerator operation amount is relatively small, it is likely that the scenario is to emphasize controllability. In this case, the reduction rate of the driving torque is set to a relatively small value, thereby enabling the driving torque to be reduced smoothly. In this way, the reduction rate of the driving torque can be set for different scenarios, namely, responsiveness and controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals denote like parts, wherein: Figure 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is a diagram illustrating control functions for various controls in the vehicle and main parts of the control system; Figure 2 is a flowchart illustrating a main portion of a control operation of an electronic control device, and is a flowchart illustrating a control operation for determining whether the accelerator operation state is rising or falling; Figure 3 This is a diagram illustrating an example of a function block for setting a torque reduction rate for different scenarios with respect to responsiveness and controllability; Figure 4 is a flowchart illustrating a main portion of a control operation of an electronic control device, and is a flowchart illustrating a control operation for setting a torque reduction rate according to different scenarios for responsiveness and controllability; and Figure 5 It means that it is executed Figure 4 FIG. 1 is a diagram showing an example of a timing chart in the case of the control operation shown in the flowchart. DETAILED DESCRIPTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0009] Figure 11 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram illustrating a main portion of a control system and control functions for various controls in the vehicle 10. Figure 1 In the figure, vehicle 10 is equipped with left and right front wheels 12, a front wheel drive device 20 that drives front wheels 12, left and right rear wheels 14, and a rear wheel drive device 30 that drives rear wheels 14, which are separated from each other. Furthermore, vehicle 10 is equipped with a battery 40, which is a rechargeable DC power source. The "left and right" mentioned above refers to left and right relative to the direction of travel of vehicle 10.

[0010] The vehicle 10 is an all-wheel drive vehicle capable of adjusting the distribution of driving torque between the front wheels 12 and the rear wheels 14. The vehicle 10 is a vehicle having four wheels, two front wheels 12 and two rear wheels 14, and is therefore also called a four-wheel drive vehicle. In this embodiment, all-wheel drive (=AWD) and four-wheel drive (=4WD) are synonymous. In addition to traveling under 4WD control (the 4WD state is also synonymous) in which driving torque is distributed to all four wheels, the vehicle 10 can also travel under two-wheel drive (=2WD) control (the 2WD state is also synonymous) in which driving torque is distributed to only one set of wheels among the front wheels 12 and the rear wheels 14. The front wheels 12 and the rear wheels 14 are each the driving wheels of the vehicle 10.

[0011] The front-wheel drive system 20 includes a front motor 22, a front-wheel power transmission device 24, and a front-wheel PCU (Power Control Unit) 26. The rear-wheel drive system 30 includes a rear motor 32, a rear-wheel power transmission device 34, and a rear-wheel PCU 36. The front motor 22 and the rear motor 32 each function as a power source for the vehicle 10. The front-wheel power transmission device 24 transmits power from the front motor 22 to the front wheels 12. The rear-wheel power transmission device 34 transmits power from the rear motor 32 to the rear wheels 14. The front-wheel PCU 26 controls the front motor 22. The rear-wheel PCU 36 controls the rear motor 32.

[0012] The front motor 22 is a well-known rotating electrical machine, a so-called electric motor / generator, and is connected to the battery 40 via the front wheel PCU 26. The front wheel power transmission device 24 includes, for example, a reduction gear mechanism including a differential gear (not shown) connected to the front motor 22, and a pair of front propeller shafts 28 connected to the reduction gear mechanism. The front wheel PCU 26 includes, for example, an inverter, etc., which converts DC power from the battery 40 into AC power and supplies it to the front motor 22. Furthermore, the front wheel PCU 26 converts AC power generated by the front motor 22 through, for example, regenerative braking into DC power and supplies it to the battery 40. The front wheel PCU 26 is a power control device that controls the power transmitted and received between the battery 40 and the front motor 22.

[0013] The rear motor 32 , the rear wheel power transmission device 34 , and the rear wheel PCU 36 have the same functions as the front motor 22 , the front wheel power transmission device 24 , and the front wheel PCU 26 , respectively, and their descriptions are omitted.

[0014] Vehicle 10 is a vehicle capable of independently controlling the amount of change in the drive torque of the front and rear wheels. It is a battery electric vehicle (BEV) with independent front and rear wheel drive. In this embodiment, when no distinction is made between the front-wheel drive unit 20 and the rear-wheel drive unit 30, they are referred to as the drive unit PU. Furthermore, when no distinction is made between the front motor 22 and the rear motor 32, they are referred to as the motor MG. Furthermore, when no distinction is made between the front-wheel power transmission unit 24 and the rear-wheel power transmission unit 34, they are referred to as the power transmission unit PT.

[0015] The vehicle 10 also includes an electronic control unit 50, which serves as a controller for the vehicle 10's control devices, including various controls related to front and rear wheel drive torque control. The electronic control unit 50 is configured, for example, by including a so-called microcomputer equipped with a CPU, RAM, ROM, and input / output interfaces. The CPU executes various controls for the vehicle 10 by performing signal processing according to programs pre-stored in the ROM while utilizing the RAM's temporary storage function.

[0016] The electronic control unit 50 is supplied with various signals based on detection values ​​generated by various sensors included in the vehicle 10. Examples of these sensors include the MGF rotation sensor 60, the MGR rotation sensor 62, wheel speed sensors 64, the accelerator position sensor 66, the G sensor 68, and the yaw rate sensor 70. Examples of these signals include the MGF rotation speed Nmgf, the MGR rotation speed Nmgr, the left and right front wheel rotation speeds Nwfl and Nwfr, the left and right rear wheel rotation speeds Nwrl and Nwrr, the accelerator position θacc, the longitudinal acceleration Gx, the lateral acceleration Gy, and the yaw rate Ryaw. The electronic control unit 50 obtains the vehicle speed V based on the front wheel rotation speeds Nwfl and Nwfr and the rear wheel rotation speeds Nwrl and Nwrr. For example, the electronic control unit 50 obtains the vehicle speed V based on the average of the front wheel rotation speeds Nwfl and Nwfr and the rear wheel rotation speeds Nwrl and Nwrr, or the average of the front wheel rotation speeds Nwfl and Nwfr or the average of the rear wheel rotation speeds Nwrl and Nwrr.

[0017] MGF speed Nmgf is the speed of the front motor 22. MGR speed Nmgr is the speed of the rear motor 32. Front wheel speeds Nwfl and Nwfr are the speeds of the front wheels 12. Rear wheel speeds Nwrl and Nwrr are the speeds of the rear wheels 14. Accelerator opening θacc is a signal indicating the magnitude of the driver's acceleration operation and is the driver's accelerator operation amount. Fore-aft acceleration Gx is the acceleration in the fore-aft direction of the vehicle 10. Lateral acceleration Gy is the acceleration in the lateral direction of the vehicle 10. Yaw rate Ryaw is the angular velocity of rotation about the vertical axis of the vehicle 10.

[0018] The electronic control unit 50 outputs various command signals to various devices included in the vehicle 10. Examples of these devices include the front wheel PCU 26 and the rear wheel PCU 36. Examples of these various command signals include the MGF control command signal Smgf and the MGR control command signal Smgr. The MGF control command signal Smgf is a torque instruction value for controlling the MGF torque Tmgf, which is the torque of the front motor 22. The MGR control command signal Smgr is a torque instruction value for controlling the MGR torque Tmgr, which is the torque of the rear motor 32.

[0019] The electronic control device 50 includes a drive control unit 52 to implement various controls in the vehicle 10 .

[0020] The drive control unit 52 controls the drive device PU. The drive control unit 52 calculates the driver's drive request for the vehicle 10 by applying the accelerator opening θacc and the vehicle speed V to the drive request map, for example. The drive request map is a relationship that is determined in advance and stored through experiments or design, that is, a predetermined relationship for calculating the drive request. The drive request uses, for example, the requested drive torque Twdem, which is the requested value of the drive torque Tw in the wheels (front wheels 12, rear wheels 14). The drive control unit 52 controls the drive of the motor MG in a manner that achieves the requested drive torque Twdem, taking into account the transmission efficiency of the power transmission device PT, etc. In addition, torque and force (driving force) are synonymous when not specifically distinguished. In addition, the accelerator opening θacc is synonymous with the current value of the accelerator opening θacc, that is, the current accelerator opening θaccr, when not specifically distinguished.

[0021] The driving torque Tw is the sum of the front torque Twf (torque at the front wheels 12) and the rear torque Twr (torque at the rear wheels 14). The requested driving torque Twdem is the sum of the requested front torque Twfdem (requested value of the front torque Twf) and the requested rear torque Twrdem (requested value of the rear torque Twr). The drive control unit 52 sets the front and rear wheel torque distribution ratio γfr by applying multiple driving force-related values, such as the accelerator position θacc, vehicle speed V, longitudinal acceleration Gx, and yaw, to a torque distribution ratio map. The torque distribution ratio map is a predefined relationship used to determine the torque distribution ratio γfr based on the driving state. The drive control unit 52 calculates the requested front torque Twfdem and the requested rear torque Twrdem based on the requested driving torque Twdem and the torque distribution ratio γfr. The drive control unit 52 outputs the MGF control command signal Smgf to the front wheel PCU 26 for controlling the front motor 22 to achieve the requested front torque Twfdem. The drive control unit 52 outputs an MGR control command signal Smgr for controlling the rear motor 32 to achieve the requested rear torque Twrdem to the rear wheel PCU 36 .

[0022] Here, when the driver performs an accelerator return operation, which changes the accelerator operation state from an increasing state to a decreasing state, the drive control unit 52 sets a torque reduction rate Rdt for reducing the requested drive torque Twdem. The torque reduction rate Rdt is the reduction rate of the drive torque Tw. When the accelerator return operation is performed, the drive control unit 52 reduces the drive torque Tw according to the torque reduction rate Rdt. The drive control unit 52 sets the torque reduction rate Rdt on the front wheel 12 side (the front side is also synonymous), i.e., the front torque reduction rate Rdtf, which is the reduction rate of the front torque Twf, for the requested front torque Twfdem. The drive control unit 52 sets the torque reduction rate Rdt on the rear wheel 14 side (the rear side is also synonymous), i.e., the rear torque reduction rate Rdtr, which is the reduction rate of the rear torque Twr, for the requested rear torque Twrdem. When the accelerator return operation is performed, the drive control unit 52 reduces the front torque Twf according to the front torque reduction rate Rdtf and reduces the rear torque Twr according to the rear torque reduction rate Rdtr. Furthermore, an increasing accelerator operation state refers to a state in which the accelerator opening θacc is increased, or a state in which the accelerator opening θacc is maintained at or near an increased value. A decreasing accelerator operation state refers to a state in which the accelerator opening θacc is decreased, or a state in which the accelerator opening θacc is maintained at or near a decreased value. In the accelerator operation state and accelerator opening θacc, "increasing" is synonymous with "increasing," and "decreasing" is synonymous with "decreasing." For convenience, the torque reduction rate Rdt is expressed in absolute values; a larger value indicates a tendency for the drive torque Tw to decrease.

[0023] However, for example, while the torque reduction rate Rdt is set for the current accelerator opening θaccr, the torque reduction rate Rdt for the accelerator opening θacc before the accelerator return operation is not set. For example, when performing an accelerator return operation to the same accelerator opening θacc consistent with stable driving, the torque reduction rate Rdt is set to the same value for both the case where the accelerator opening θacc is started from a high opening and the case where the accelerator opening θacc is started from a low opening. On the other hand, the accelerator return operation, which changes the accelerator opening θacc from a high opening to one consistent with stable driving, is a scenario where responsiveness is prioritized. Alternatively, the accelerator return operation, which changes the accelerator opening θacc from a low opening to one consistent with stable driving, is a scenario where controllability is prioritized. If the torque reduction rate Rdt is uniformly set for the current accelerator opening θaccr, it becomes impossible to distinguish between scenarios where responsiveness is prioritized and scenarios where controllability is prioritized. Therefore, when the torque reduction rate Rdt is set based on an accelerator return operation from a high opening to a state consistent with stable driving, a relatively large value of the torque reduction rate Rdt is set regardless of the accelerator opening θacc prior to the accelerator return operation. This may result in poor controllability when an accelerator return operation is performed from a low opening to a state consistent with stable driving. Alternatively, when the torque reduction rate Rdt is set based on an accelerator return operation from a low opening to a state consistent with stable driving, a relatively small value of the torque reduction rate Rdt is set regardless of the accelerator opening θacc prior to the accelerator return operation. This may result in poor responsiveness when an accelerator return operation is performed from a high opening to a state consistent with stable driving.

[0024] The aforementioned issue of being unable to distinguish between scenarios where responsiveness is prioritized and scenarios where controllability is prioritized can also occur if the torque reduction rate Rdt is uniformly set for the accelerator opening θacc prior to the accelerator return operation. For example, if the torque reduction rate Rdt is set to the same value for both cases where the current accelerator opening θaccr is set to a high opening and a low opening, the aforementioned issue can arise.

[0025] Therefore, the greater the change in accelerator opening θacc from the time the accelerator return operation is performed to the current time, the greater the value at which the torque reduction rate Rdt is set by the drive control unit 52 when the requested drive torque Twdem is reduced. The change in accelerator opening θacc from the time the accelerator return operation is performed to the current time is the difference between the accelerator opening θacc at the time the accelerator return operation is performed and the current accelerator opening θaccr.

[0026] For example, when the accelerator return operation to the same current accelerator opening θaccr is performed from a larger value of the accelerator opening θacc, the drive control unit 52 sets the torque reduction rate Rdt to a larger value than when the accelerator opening θacc is performed from a smaller value. And / or, when the accelerator return operation is performed from the same accelerator opening θaccr to a smaller value of the current accelerator opening θaccr, the drive control unit 52 sets the torque reduction rate Rdt to a larger value than when the accelerator opening θaccr is performed from a larger value of the current accelerator opening θaccr.

[0027] The drive control unit 52 includes, for example, an accelerator operation state determination unit 54 , a reference operation amount setting unit 56 , and a torque reduction rate setting unit 58 , and sets the torque reduction rate Rdt according to different scenarios in terms of responsiveness and controllability.

[0028] Figure 2 This is a flowchart explaining a main part of the control operation of the electronic control device 50 , and is a flowchart explaining a control operation for determining whether the accelerator operation state is rising or falling, and is executed repeatedly, for example.

[0029] exist Figure 2 In the flowchart, each step corresponds to the function of the accelerator operation state determination unit 54. In step (hereinafter referred to as "step") S10, a determination is made as to whether the current accelerator opening θaccr is greater than the value obtained by adding the previous value of the accelerator opening θacc to a predetermined increasing opening. The previous value of the accelerator opening θacc is, for example, the value obtained a predetermined number of times before the flowchart loop or a predetermined time before. The predetermined increasing opening is, for example, a predetermined amount corresponding to a hysteresis for determining whether the accelerator opening θacc is increasing. If the determination in step S10 is affirmative, the accelerator operation state is determined to be increasing in step S20. If the determination in step S10 is negative, the accelerator operation state is determined to be increasing in step S30. If the current accelerator opening θaccr is less than the value obtained by subtracting a predetermined decreasing opening from the previous value of the accelerator opening θacc. The predetermined decreasing opening is, for example, a predetermined amount corresponding to a hysteresis for determining whether the accelerator opening θacc is decreasing. If the determination in step S30 is affirmative, the accelerator operation state is determined to be decreasing in step S40. If the determination in S30 is negative, the previous value of the rising determination or falling determination is held in S50. This previous value is the value before one cycle of the flowchart.

[0030] Figure 3 This figure illustrates an example of a function block for setting the torque reduction rate Rdt according to different scenarios in terms of responsiveness and controllability. Figure 3In FIG. 5 , block B10 corresponds to the function of the accelerator operation state determination unit 54 , block B20 corresponds to the function of the reference operation amount setting unit 56 , and block B30 corresponds to the function of the torque reduction rate setting unit 58 .

[0031] In block B10, the accelerator operation state is determined based on the current accelerator opening θaccr. For example, it is determined based on the current accelerator opening θaccr whether the accelerator operation state is rising or falling (refer to Figure 2 ). Furthermore, based on whether the accelerator operation state changes from rising to falling, it is determined whether the accelerator return operation has been performed. In this way, the accelerator operation state determination unit 54 determines whether the accelerator return operation has been performed.

[0032] In block B20, the accelerator disconnect reference opening θaccb is calculated based on the current accelerator opening θaccr and the accelerator operation state. The accelerator disconnect reference opening θaccb is the accelerator opening θacc, or reference operation variable, that serves as a reference for determining the change in accelerator opening θacc from the time the accelerator return operation was performed to the current time. For example, if a determination that an accelerator return operation has been performed is not input, the current accelerator disconnect reference opening θaccb is maintained. If a determination that an accelerator return operation has been performed is input, the accelerator disconnect reference opening θaccb is updated to the current value of the accelerator opening θaccr. Thus, the reference operation variable setting unit 56 sets the accelerator opening θacc at the time the accelerator return operation was performed as the accelerator disconnect reference opening θaccb.

[0033] In block B30, the torque reduction rate Rdt is calculated based on the current accelerator opening θaccr and the accelerator-off reference opening θaccb. A front torque reduction rate Rdtf and a rear torque reduction rate Rdtr are calculated so that the drive torque Tw is reduced according to the calculated torque reduction rate Rdt. For example, the torque reduction rate Rdt is set by applying the current accelerator opening θaccr and the accelerator-off reference opening θaccb to a torque reduction map. The torque reduction map is a predetermined relationship used to determine the torque reduction rate Rdt based on the accelerator operation state. In the torque reduction map, for example, the greater the difference between the accelerator-off reference opening θaccb and the current accelerator opening θaccr, namely the reference opening difference Δθaccb (=θaccb - θaccr), the greater the torque reduction rate Rdt is set to. For example, when the current accelerator opening θaccr is the same, the torque reduction rate Rdt is set to a larger value when the accelerator-off reference opening θaccb is larger than when it is smaller. And / or, when the accelerator-off reference opening θaccb is the same value, the torque reduction rate Rdt is set to a larger value when the current accelerator opening θaccr is smaller than when it is larger.

[0034] As described above, the torque reduction rate setting unit 58 sets the torque reduction rate Rdt to a larger value as the reference opening difference Δθaccb increases. For example, when the accelerator-off reference opening θaccb is larger relative to the current accelerator opening θaccr, the torque reduction rate setting unit 58 sets the torque reduction rate Rdt to a larger value than when the accelerator-off reference opening θaccb is smaller. Furthermore, / or when the current accelerator opening θaccr is smaller relative to the accelerator-off reference opening θaccb, the torque reduction rate setting unit 58 sets the torque reduction rate Rdt to a larger value than when the current accelerator opening θaccr is larger.

[0035] Figure 4 This is a flowchart explaining the main part of the control operation of the electronic control device 50 , and is a flowchart explaining the control operation for setting the torque reduction rate Rdt according to different scenarios in terms of responsiveness and controllability, and is executed repeatedly, for example.

[0036] exist Figure 4In the process, first, in S110 corresponding to the function of the accelerator operation state determination unit 54, it is determined whether the accelerator operation state changes from rising to falling. In the case where the judgment of S110 is affirmative, in S120 corresponding to the function of the reference operation amount setting unit 56, the accelerator disconnection reference opening θaccb is updated to the value of the current accelerator opening θaccr. In the case where the judgment of the above S110 is negative, in S130 corresponding to the function of the reference operation amount setting unit 56, the previous value of the accelerator disconnection reference opening θaccb is maintained. The previous value is the value before 1 cycle of the flowchart. Immediately following the above S120 or the above S130, in S140 corresponding to the function of the torque reduction rate setting unit 58, the torque reduction rate Rdt is calculated based on the current accelerator opening θaccr and the accelerator disconnection reference opening θaccb. The above S110 corresponds to Figure 3 The above S120 and S130 correspond to Figure 3 The above S140 corresponds to Figure 3 Block B30.

[0037] Figure 5 Indicates that it is executed Figure 4 The flowchart is an example of a timing diagram in the case of a control operation. Figure 5 In the figure, time t1 represents the moment when the accelerator operation state is determined to have changed from rising to falling by disconnecting the accelerator from the fully opened state, i.e., when the accelerator return operation is determined to have been performed. Furthermore, the value of the current accelerator opening θaccr at time t1 is set as the accelerator disconnect reference opening θaccb. The current accelerator opening θaccr is reduced from time t1, and the reference opening difference Δθaccb is increased accordingly, thereby increasing the front torque reduction rate Rdtf and the rear torque reduction rate Rdtr (refer to time t1 - time t2). At time t2, the accelerator is engaged, causing the accelerator operation state to change to rising (refer to time t2 - time t3). Then, at time t3, the accelerator is disconnected again, determining that the accelerator return operation has been performed, and the accelerator disconnect reference opening θaccb is updated to the value of the current accelerator opening θaccr at time t3. Subsequently, similarly, at time t4, the accelerator operation state is changed to rising. At time t5, it is determined that the accelerator return operation has been performed, and the accelerator-off reference opening θaccb is updated to the current accelerator opening θaccr. Furthermore, even during the period when the accelerator operation state is determined to be rising, the front torque reduction rate Rdtf and the rear torque reduction rate Rdtr are calculated for convenience. However, during the period when the accelerator operation state is determined to be rising, the torque reduction rate Rdt is not reflected in the drive control of the vehicle 10.

[0038] As described above, according to this embodiment, the greater the change in accelerator opening θacc from the time the accelerator return operation is performed to the current time, the greater the torque reduction rate Rdt is set to when reducing the requested drive torque Twdem. Thus, when the change in accelerator opening θacc is relatively large, responsiveness is likely to be emphasized. In this case, the torque reduction rate Rdt is set to a relatively large value, thereby enabling a rapid reduction in drive torque Tw. On the other hand, when the change in accelerator opening θacc is relatively small, controllability is likely to be emphasized. In this case, the torque reduction rate Rdt is set to a relatively small value, thereby enabling a gradual reduction in drive torque Tw. This allows the torque reduction rate Rdt to be set according to different scenarios, such as responsiveness and controllability.

[0039] Furthermore, according to this embodiment, whether an accelerator return operation has been performed is determined. The accelerator opening θacc at the time of the accelerator return operation is set as the accelerator-off reference opening θaccb. The greater the reference opening difference Δθaccb (=θaccb - θaccr), the greater the torque reduction rate Rdt is set to. This allows the torque reduction rate Rdt to be appropriately set based on the responsiveness and controllability of each scenario.

[0040] Furthermore, according to this embodiment, when the accelerator-off reference opening θaccb is relatively large relative to the current accelerator opening θaccr, the torque reduction rate Rdt is set to a larger value than when the accelerator-off reference opening θaccb is relatively small. Thus, when the reference opening difference Δθaccb is relatively large, the torque reduction rate Rdt is appropriately set to a relatively large value. On the other hand, when the reference opening difference Δθaccb is relatively small, the torque reduction rate Rdt is appropriately set to a relatively small value.

[0041] Furthermore, according to this embodiment, when the current accelerator opening θaccr is relatively small relative to the accelerator-off reference opening θaccb, the torque reduction rate Rdt is set to a larger value than when the current accelerator opening θaccr is relatively large. Thus, when the reference opening difference Δθaccb is relatively large, the torque reduction rate Rdt is appropriately set to a relatively large value. On the other hand, when the reference opening difference Δθaccb is relatively small, the torque reduction rate Rdt is appropriately set to a relatively small value.

[0042] Furthermore, according to this embodiment, when the accelerator return operation to the same current accelerator opening θaccr is performed from a larger accelerator opening θacc, the torque reduction rate Rdt is set to a larger value compared to when the accelerator opening θacc is performed from a smaller accelerator opening θacc. And / or, when the accelerator return operation is performed from the same accelerator opening θaccr to a smaller current accelerator opening θaccr, the torque reduction rate Rdt is set to a larger value compared to when the accelerator opening θaccr is performed from a larger current accelerator opening θaccr. Thus, when the reference opening difference Δθaccb is relatively large, the torque reduction rate Rdt is appropriately set to a relatively large value. On the other hand, when the reference opening difference Δθaccb is relatively small, the torque reduction rate Rdt is appropriately set to a relatively small value.

[0043] As mentioned above, although the embodiment of the present invention was described in detail based on the drawings, the present invention can also be applied to other aspects.

[0044] For example, in the aforementioned embodiment, a BEV with independent front and rear wheel drive is exemplified as the vehicle 10, but the present invention is not limited to this embodiment. For example, the vehicle 10 may be an electric vehicle such as a well-known HEV (Hybrid Electric Vehicle), a well-known PHEV (Plug-in Hybrid Electric Vehicle), or a well-known FCEV (Fuel Cell Electric Vehicle). The vehicle 10 may also be a well-known engine vehicle. In addition, the vehicle 10 may be a well-known AWD vehicle that distributes power to the front and rear wheels through a transfer case or the like, or a well-known 2WD vehicle. The present invention can be applied to any vehicle as long as it has a power source and a power transmission device that transmits power from the power source to the drive wheels.

[0045] The above-mentioned content is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Claims

1. A vehicle control device, characterized in that: comprising: a power source; and a power transmission device for transmitting power from the power source to the drive wheels, The vehicle control device includes a drive control unit that sets a larger value for a reduction rate of the drive torque when the drive torque is reduced toward a requested value of the drive torque based on a current value of the accelerator operation amount as the change in the accelerator operation amount from the time when the accelerator return operation is performed to the current time is larger, The accelerator return operation is an operation in which the accelerator operation state changes from an increasing state to a decreasing state.

2. The vehicle control device according to claim 1, wherein: The drive control unit includes: an accelerator operation state determination unit for determining whether the accelerator return operation has been performed; a reference operation amount setting unit that sets the accelerator operation amount at the time when the accelerator return operation is performed as a reference operation amount; as well as The torque reduction rate setting unit sets the reduction rate of the driving torque to a larger value as the difference between the reference operation amount and the current value of the accelerator operation amount increases.

3. The vehicle control device according to claim 2, characterized in that: When the reference operation amount is a larger value relative to the current value of the accelerator operation amount, the torque reduction rate setting unit sets the reduction rate of the drive torque to a larger value than when the reference operation amount is a smaller value.

4. The vehicle control device according to claim 2 or 3, characterized in that: When the current value of the accelerator operation amount is smaller than the reference operation amount, the torque reduction rate setting unit sets the reduction rate of the drive torque to a larger value than when the current value of the accelerator operation amount is larger.

5. The vehicle control device according to claim 1, wherein: When the accelerator return operation is performed from a larger value of the accelerator operation amount to the current value of the accelerator operation amount, the drive control unit sets the reduction rate of the drive torque to a larger value than when the accelerator operation amount is performed from a smaller value. Alternatively, for the accelerator return operation starting from the same value of the accelerator operation amount, when the current value of the accelerator operation amount is a smaller value, the drive control unit sets the reduction rate of the drive torque to a larger value compared to when the current value of the accelerator operation amount is a larger value.

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