Vehicle control system

Abstract

In a vehicle (1) capable of executing a normal mode in which acceleration control by an accelerator operation and deceleration control by a brake operation are performed, and a one-pedal mode in which acceleration and deceleration are controlled only by an accelerator pedal, the present invention comprises: a torque setting unit (21) that sets, in each of the normal mode and the one-pedal mode, a driver request torque from an accelerator request torque set in accordance with a vehicle speed and an accelerator operation amount; and a control unit (22) that controls the operation of electric motors (3, 4) in accordance with the driver request torque. The torque setting unit (21) has a rate-of-change limiting unit (23) that limits the rate of change of the driver request torque to within a limit rate of change at the time of mode switching from the one-pedal mode to the normal mode, and the absolute value of the limit rate of change when the driver request torque is negative is greater than the absolute value of the limit rate of change when the driver request torque is positive.

Description

Vehicle control system

[0001] The present invention relates to a vehicle control system that includes a traveling motor and a generator and is capable of implementing a normal mode and a one-pedal mode.

[0002] In recent years, vehicles implementing a one-pedal mode that enables acceleration and deceleration to be controlled only with an accelerator pedal have been developed (for example, Patent Document 1). According to this one-pedal mode, the vehicle accelerates when the accelerator pedal is depressed and decelerates when the accelerator pedal is released, thereby reducing the effort required to switch to the brake pedal and allowing the driver to concentrate on steering operation. Further, in some one-pedal mode configurations, when the accelerator pedal is released, a mechanical brake device is activated accordingly to decelerate the vehicle, and at this time, the brake pedal is also interlocked and pulled toward the depressed side.

[0003] Japanese Unexamined Patent Application Publication No. 2021-181290

[0004] By the way, it has been found that in vehicles capable of implementing the one-pedal mode, when switching from the one-pedal mode to the normal mode, temporary excessive deceleration may occur in the vehicle. Such excessive deceleration of the vehicle may impair driving feel and riding comfort.

[0005] The vehicle control system of the present disclosure has been devised in view of such problems, and one of the objects thereof is to suppress occurrence of temporary excessive deceleration in the vehicle when switching from the one-pedal mode to the normal mode. It should be noted that the present invention is not limited to this object, and it is also another object of the present disclosure to achieve operational effects that cannot be obtained by conventional techniques, which are derived from each configuration shown in the embodiments for carrying out the invention described later.

[0006] The vehicle control system disclosed herein can be implemented as the aspect (application example) disclosed below, and solves at least a part of the above problems. Each of the aspects from aspect 2 onward is an aspect that can be additionally appropriately selected, and any of them can be omitted. None of the aspects from aspect 2 onward discloses aspects or configurations that are indispensable to the present disclosure.

[0007] Embodiment 1. The disclosed vehicle control system is provided for a vehicle equipped with a first motor for driving and a second motor capable of generating electricity from inertial energy, and is a control system capable of performing acceleration control by operating the accelerator pedal and deceleration control by operating the brake pedal, and a one-pedal mode in which acceleration and deceleration control is performed by operating only the accelerator pedal. In this control system, when the one-pedal mode is selected, the brake pedal is automatically moved to the depressed side in conjunction with the operation of a mechanical brake device when the accelerator pedal is released during deceleration operation. Furthermore, the control system includes, in both the normal mode and the one-pedal mode, a torque setting unit that sets a driver-requested torque from an accelerator-requested torque set according to the vehicle speed and the amount of operation of the accelerator pedal, and a control unit that controls the operation of at least one of the first motor, the second motor, and the brake device according to the set driver-requested torque. The torque setting unit has a change rate limiting unit that limits the rate of change of the driver-requested torque to within a limit rate of change when switching modes from the one-pedal mode to the normal mode. The absolute value of the limit change rate when the driver-required torque is negative is greater than the absolute value of the limit change rate when the driver-required torque is positive.

[0008] Embodiment 2. In Embodiment 1 described above, it is preferable that the rate of change limiting unit obtains the limit rate of change using a map with the driver-requested torque as an argument.

[0009] Embodiment 3. In Embodiment 1 or 2 described above, the control system preferably comprises a regenerative braking level selection switch and a drive mode selection switch. The regenerative braking level selection switch is operated when selecting one of several regenerative braking levels for the magnitude of regenerative braking using the second motor as a power generation load. The drive mode selection switch is operated when selecting one of several drive modes, including a normal mode, an eco mode that prioritizes fuel efficiency, and a sport mode that prioritizes driving performance. Furthermore, in the control system, when the one-pedal mode is selected, the operation of the regenerative braking level selection switch is disabled, and when the normal mode is selected, the operation of the regenerative braking level selection switch is enabled. When switching from the one-pedal mode to the normal mode while the sport mode is selected as the drive mode, the system automatically selects a predetermined regenerative braking level with a high degree of regeneration from among several regenerative braking levels. Furthermore, when the regeneration level is selected, the torque setting unit sets the driver-requested torque to a value obtained by adding a correction torque corresponding to the regeneration level to the accelerator-requested torque, and preferably the torque setting unit has an addition limiting unit that limits the addition of the correction torque when setting the driver-requested torque during mode switching.

[0010] Embodiment 4. In Embodiment 3 described above, it is preferable that the predetermined regenerative level is the maximum level at which the regenerative braking level is highest.

[0011] Appearance 5. In Appearance 4 described above, it is preferable that the torque setting unit calculates a subtraction value by subtracting the value after limiting the rate of change of the accelerator request torque from the sum of the value before limiting the rate of change of the accelerator request torque and the correction torque, sets the larger of the smaller of the subtraction value and the value of 0 and the correction torque as the addition limit correction torque, and sets the driver request torque to the accelerator request torque plus the addition limit correction torque.

[0012] Embodiment 6. In Embodiment 5 described above, it is preferable that the torque setting unit limits the addition of the correction torque until the accelerator request torque converges.

[0013] According to the disclosed vehicle control system, when switching from one-pedal mode to normal mode, it is possible to suppress the temporary excessive deceleration of the vehicle.

[0014] This is a diagram showing the configuration of a vehicle equipped with a control system according to the embodiment. This is a block diagram showing the configuration of the control system according to the embodiment. This is a table explaining the drive modes. This is a block diagram showing the flow of calculation of the requested torque by the control device. This is a block diagram showing the flow of calculation of the driver-requested torque by the control device. This is a time chart explaining the first control that suppresses the occurrence of excessive deceleration. This is a time chart explaining the second control that suppresses the occurrence of excessive deceleration.

[0015] A vehicle control system as an embodiment will be described with reference to the drawings. The embodiments shown below are merely illustrative, and there is no intention to exclude various modifications or applications of technologies not explicitly shown in the embodiments below. Each component of these embodiments can be modified in various ways without departing from their spirit. Furthermore, components can be selected or combined as needed.

[0016] The control system is installed in a vehicle (electric vehicle) equipped with a first motor for propulsion and a second motor capable of generating electricity from inertial energy. In other words, the vehicles to which the control system is applied may be electric vehicles (EVs), hybrid electric vehicles (HEVs), or plug-in hybrid electric vehicles (PHEVs) capable of both motor-driven operation and regenerative power generation. A plug-in hybrid electric vehicle refers to a hybrid electric vehicle capable of external charging of the battery or external power supply from the battery. Plug-in hybrid electric vehicles are provided with a charging port (inlet) for inserting a charging cable into which power is supplied from an external charging facility, and an outlet for external power supply.

[0017] The first and second motors may be the same (common) motor (i.e., motor-generator) or different (separate) motors. In the latter case, the first motor is at least a motor or motor-generator that functions as a motor (driving source), and the second motor is at least a generator or motor-generator that functions as a generator. The number of first and second motors is not specified.

[0018] Furthermore, this control system is configured to enable two modes: a normal mode in which acceleration is controlled by operating the accelerator pedal and deceleration by operating the brake pedal, and a one-pedal mode in which acceleration and deceleration are controlled by operating only the accelerator pedal. The one-pedal mode is a mode selected by the driver. For example, if the vehicle is running in normal mode and the driver selects the one-pedal mode, the vehicle will switch from normal mode to one-pedal mode. Conversely, if the vehicle is running in one-pedal mode and the driver selects normal mode, the vehicle will switch from one-pedal mode to normal mode.

[0019] In this vehicle's control system, when one-pedal mode is selected, the brake pedal is automatically moved to the depressed position in conjunction with the activation of the mechanical braking system when the accelerator pedal is released during deceleration. In other words, in one-pedal mode, even if the driver is not pressing the brake pedal, when the accelerator pedal is released and the mechanical braking system is activated, the brake pedal is automatically retracted in conjunction with it.

[0020] [1. Overall Configuration] Figure 1 is a schematic diagram showing the configuration of a vehicle 1 to which the control system 10 according to this embodiment is applied, and Figure 2 is a block diagram showing the configuration of the control system 10 according to this embodiment. As shown in Figures 1 and 2, the vehicle 1 according to this embodiment is a vehicle (PHEV) equipped with a battery 2, a front motor 3F and a rear motor 3R as drive motors 3, a generator 4, an engine 5, and a transaxle 6.

[0021] Battery 2 is the drive battery (high-voltage battery) for vehicle 1, and is a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride battery. Motors 3 (3F, 3R) and generators 4 are both motor-generators that combine the functions of an electric motor and a generator. Motor 3 is a drive source that exchanges power with battery 2, and mainly functions as an electric motor to drive vehicle 1, and functions as a generator during regeneration (deceleration). In this embodiment, a four-wheel drive vehicle 1 (electric vehicle) equipped with a front motor 3F that drives the front wheels and a rear motor 3R that drives the rear wheels is shown as an example, but it is sufficient for one motor 3 to be provided on at least one of the front or rear sides.

[0022] The generator 4 is connected to the engine 5 and can operate independently of the operating state of the motors 3 (3F, 3R). In this embodiment, the generator 4 and engine 5 are located on the front side. The generator 4 functions as a starting motor (starter) when starting the engine 5, and when the engine 5 is running, it is driven by the engine power to generate electricity and supply power to the battery 2. An inverter (not shown) that converts DC current to AC current is provided around (or inside) each of the motors 3 and generator 4. The rotational speeds of the motors 3 and generator 4 are controlled by controlling the inverters.

[0023] The front wheels (drive wheels) are connected in parallel to the front motor 3F and the engine 5 via the transaxle 6, and the power from the front motor 3F and the engine 5 is transmitted individually. In addition, the engine 5 is connected in parallel to the generator 4 and the front wheels via the transaxle 6, and the power from the engine 5 is transmitted to the generator 4 in addition to the front wheels. The transaxle 6 is a power transmission device that integrates a final drive (final reduction gear) including a differential gear and a transmission (reduction gear), and incorporates multiple mechanisms that are responsible for power transmission between the drive source and the driven device.

[0024] Motor 3 (3F, 3R) is both a first motor for driving and a second motor capable of generating electricity using inertial energy. Furthermore, if the generator 4 is configured to generate electricity from the rotation of the front wheels (drive wheels), the generator 4 can also function as a second motor capable of generating electricity using inertial energy.

[0025] Furthermore, the vehicle 1 is equipped with a mechanical brake system 7 (in this embodiment, a hydraulic brake system 7) that mechanically applies frictional braking force to each wheel, and a regenerative brake system that applies braking force by operating (regenerating) the motor 3 (3F, 3R) as a second electric motor to provide a regenerative load to the power system of the vehicle 1.

[0026] The hydraulic brake system 7 applies hydraulic pressure to the calipers 7a mounted on each wheel of the vehicle 1, causing the calipers 7a to grip brake discs (not shown) and apply braking force to the wheels. Each caliper 7a can be controlled individually. The hydraulic brake system 7 and the regenerative brake system can be used together using coordinated control so that the combined braking force of both brake systems generates the necessary braking force for the vehicle 1.

[0027] Vehicle 1 is equipped with a higher-level electronic control unit (ECU) 20 that integrates and controls various on-board devices. The higher-level ECU 20 is called, for example, an EV-ECU or a PHEV-ECU. In addition, lower-level electronic control units (ECUs) are provided for each on-board device, such as a PDU (Power Drive Unit) 30 that controls the front motor 3F and generator 4, an RMCU (Rear Motor Control Unit) 40 that controls the rear motor 3R, a B-ECU (Brake-Electronic Control Unit) 50 that controls the hydraulic brake system 7, and a BMU (Battery Management Unit) 60 that manages the battery 2.

[0028] Furthermore, the vehicle 1 is equipped with sensors and selection switches that output various information used for controlling the electronic control unit. The vehicle 1 in this embodiment is equipped with an accelerator opening sensor 71, a brake sensor 72, a shift position sensor 73, a vehicle speed sensor 74, a drive mode selector 75 (drive mode selection switch), an i-Pedal mode SW 76 (one-pedal mode selection switch), and a paddle shift 77 (regeneration level selection switch).

[0029] The accelerator pedal position sensor 71 detects the accelerator pedal depression operation (accelerator opening degree and the resulting accelerator opening speed, etc.). The brake sensor 72 detects the brake pedal depression operation (whether or not the brakes are applied and the amount of depression, etc.). The shift position sensor 73 detects the shift position. In this embodiment, the shift positions are R range, P range, N range and D range. The vehicle speed sensor 74 detects the vehicle speed of the vehicle 1.

[0030] The drive mode selector 75 is an input device operated when selecting one of several drive modes. For example, a dial-type selector is used, where one of the drive modes is selected by rotating the dial. A drive mode refers to a control method that corresponds to the relationship between the vehicle's driving operation and the operating state of the drivetrain and braking system. By switching drive modes, various characteristics that determine the vehicle's dynamic performance (e.g., cornering performance, drive-braking performance, driving stability performance, steering response performance, four-wheel drive performance, AYC performance, ABS performance, ASC performance, etc.) are changed, making it easier to achieve driving that matches various driving conditions.

[0031] The drive modes include, for example, Normal mode, Snow mode, Gravel mode, Eco mode, Mud mode, Power mode, and Tarmac mode, as shown in Figure 3. Normal mode is the mode selected in the initial state (default) and is used for driving on normal paved roads in normal weather conditions (sunny, cloudy, rainy, etc.). Snow mode is a mode mainly suitable for driving on snowy roads, and in this mode, control is implemented to improve stability and slip resistance on slippery surfaces. Gravel mode is a mode suitable for driving on gravel roads and unpaved roads, and in this mode, control is implemented to improve the off-road and cornering performance of the four-wheel drive system.

[0032] Eco mode is a mode suitable for ecological and economical driving. In this mode, control is implemented to operate the engine 5 in a way that improves its fuel efficiency at least compared to normal mode. For example, eco mode reduces fuel consumption by slowing down the increase in engine 5's output in response to an increase in accelerator opening. In addition, in eco mode, control may also be implemented to operate the motors 3 (3F, 3R) in a way that improves their electric efficiency.

[0033] Mud mode is suitable for driving on sandy, muddy, and deep snowy roads, and in this mode, control is implemented to improve traction and straight-line stability. Power mode is a high-output mode suitable for powerful and sporty driving, and in this mode, control is implemented to enhance responsiveness and acceleration. Tarmac mode is suitable for driving nimbly on dry paved roads, and in this mode, control is implemented to make driving behavior more agile and enhance driving enjoyment. Power mode and Tarmac mode are drive modes that prioritize driving performance suitable for so-called sporty driving, and are also referred to as Sport mode.

[0034] The i-Pedal mode SW76 is a switch operated when selecting i-Pedal mode (short for "Innovative Pedal Operation Mode," equivalent to "One-Pedal Mode"), which allows acceleration and deceleration to be controlled using only the accelerator pedal. The i-Pedal mode SW76 can also be called the One-Pedal Mode Selection Switch, and is provided, for example, as an on / off switch (physical switch) near the steering wheel. With i-Pedal mode, pressing the accelerator pedal accelerates the vehicle, and releasing it decelerates it, which has the advantage of reducing the effort required to switch to the brake pedal, allowing the driver to concentrate on steering.

[0035] By turning the i-Pedal mode switch 76 on, the i-Pedal mode can be set, and by turning the i-Pedal mode switch 76 off, the normal mode can be set, which performs acceleration control by operating the accelerator pedal and deceleration control by operating the brake pedal. When i-Pedal mode is set, deceleration is performed using the hydraulic brake system 7, and in the case of this control system 10, when the hydraulic brake system 7 is used, the brake pedal is automatically moved to the depressed position in conjunction with it.

[0036] The paddle shift 77 is an input device for stepwise changing the regenerative braking level (regenerative braking level, degree of regeneration), which is the magnitude of regenerative braking (i.e., it is operated when selecting one of several regenerative levels). The paddle shift 77 is provided, for example, as a lever (physical switch) near the steering wheel. The regenerative level is selectively set from several levels according to the occupant's (driver's) preference. In this embodiment, six regenerative levels, B0 to B5, can be set. The regenerative levels are B0 being the lowest, and then increasing sequentially as B1, B2, ..., with B5 being the highest. For example, by setting regenerative level B2 to be equivalent to the regenerative level in D range, setting the regenerative level to B1 or B0 will reduce the regenerative level compared to normal operation (D range).

[0037] Furthermore, this vehicle 1 is equipped with a system called VDC (Vehicle Dynamics Control) system, which suppresses skidding and wheel spin of the drive wheels to improve vehicle stability during driving. In addition to the VDC function, which improves vehicle stability during driving by detecting skidding conditions using necessary sensors, this system also has a TCS (Traction Control System) function and a brake LSD (Limited Slip Differential) function.

[0038] Furthermore, the settings made by selecting the drive mode using the drive mode selector 75, the setting of the i-Pedal mode using the i-Pedal mode switch 76, and the settings made using the paddle shifters 77 are, in principle, performed on the premise that the vehicle is set to D range. Also, these settings cannot be performed completely independently of each other. For example, when the i-Pedal mode switch 76 is set to ON, the paddle shifters 77 cannot be operated, but the paddle shifters 77 can be operated only when the i-Pedal mode switch 76 is set to OFF, which is the normal mode.

[0039] Furthermore, when the drive mode is set to power mode or tarmac mode (i.e., sport mode), switching the i-Pedal mode SW76 from on to off activates the paddle shift 77, and immediately after this switch, the regeneration level is automatically set to the highest level, "B5". This is to make it easier to drive briskly in sport mode by setting the regeneration level to the highest level. However, as will be described later, it has been found that this setting causes a temporary excessive deceleration of the vehicle 1 when switching from i-Pedal mode to normal mode. Therefore, the control system 10 implements control to prevent the occurrence of excessive deceleration.

[0040] [2. Control Configuration] As described above, each part of the vehicle 1 is controlled by the higher-level ECU 20 and a plurality of lower-level ECUs (PDU 30, RMCU 40, B-ECU 50, BMU 60, etc.) based on information from the accelerator opening sensor 71, brake sensor 72, shift position sensor 73, vehicle speed sensor 74, drive mode selector 75, i-Pedal mode SW 76, paddle shift 77, etc.

[0041] As shown in Figure 2, the upper-level ECU 20 is provided with a torque setting unit 21 and a control unit 22. The torque setting unit 21 also includes a rate of change limiting unit 23 and an addition limiting unit 24. These functional elements may be implemented by electronic circuits (hardware), programmed as software, or some of these functions may be provided as hardware and the others as software.

[0042] The torque setting unit 21 sets the accelerator request torque according to the vehicle speed of the vehicle 1 and the amount of accelerator pedal operation in both the normal mode and the i-Pedal mode, and sets the driver request torque from the set accelerator request torque. The control unit 22 controls the operation of at least one of the first motor, the second motor, and the mechanical brake device according to the driver request torque set by the torque setting unit 21. In this embodiment, the control unit 22 controls the operation of at least one of the motors 3 (3F, 3R) and the hydraulic brake device 7, but it may also include the control of the generator 4.

[0043] The rate of change limiting unit 23 limits the rate of change of the driver-requested torque to within a limit rate of change in order to suppress abrupt changes in the driver-requested torque when switching from i-Pedal mode to normal mode. In addition, the addition limiting unit 24 limits the addition of the correction torque (paddle correction torque) that is added in accordance with the shift operation of the paddle shift 77 when setting the driver-requested torque. The torque setting by the torque setting unit 21 and the control by the control unit 22 will be described below with reference to Figures 4 and 5.

[0044] FIG. 4 is a block diagram showing the flow of torque calculation requested to each unit by the upper ECU 20 included in the control system 10, and this calculation is performed at a predetermined calculation cycle (for example, several ms to several tens of ms). Regarding acceleration of the vehicle 1, the output torques of the front motor 3F and the rear motor 3R are controlled. When the vehicle 1 is in a mode (so-called parallel mode) in which the vehicle also travels using the power of the engine 5, the output torque of the engine 5 may also be controlled. Regarding deceleration of the vehicle 1, the hydraulic brake torque of the hydraulic brake device 7 and the power generation load (regenerative cooperative torque) of the regenerative brake device are controlled. In FIG. 4, calculation units C10 to C70 are processing performed by the torque setting unit 21, and calculation unit C80 is processing performed by the control unit 22.

[0045] To calculate each requested torque, as shown in FIG. 4, first, a driver requested torque Tr1 is calculated by a calculation unit C10. The driver requested torque Tr1 is calculated according to respective pieces of information including the vehicle speed, accelerator opening degree (APS), currently selected shift mode, currently selected drive mode, and the on / off state of the i-Pedal mode. Operation information of the paddle shift 77 may also be taken into consideration.

[0046] Furthermore, when the driver requested torque Tr1 is a negative value, for example, when the i-Pedal mode is currently selected and the accelerator opening degree becomes equal to or less than a reference value after releasing the accelerator pedal, that is, when a deceleration request is made, a target coast torque Ttc to be borne also by the hydraulic brake device 7 is set. A lower limit value TtcL is provided for the target coast torque Ttc. The lower limit value TtcL takes different values depending on whether the i-Pedal mode is on or off. The target coast torque lower limit value TtcL is, for example, set to a maximum value that can be set as the target coast torque Ttc (for example, -3000 to -2000 [Nm]) when the i-Pedal mode is on, and set to 0 [Nm] when the i-Pedal mode is off.

[0047] The driver requested torque Tr1 calculated by the calculation unit C10 is compared with the target coast torque lower limit value TtcL by the calculation unit C20, and the larger one of these is output. Accordingly, the target coast torque Ttc becomes a value equal to or greater than the target coast torque lower limit value TtcL. The value of the target coast torque Ttc obtained through the calculation unit C20 in this way is compared with a value 0 by the calculation unit C30, and the smaller one of these is output as the current target coast torque Ttc. When the driver requested torque Tr1 is negative, the output from the calculation unit C20 is a negative value, so the calculation unit C30 performs a process to exclude the case where the driver requested torque Tr1 is positive.

[0048] The target coast torque Ttc obtained through the calculation unit C30 is output to the calculation unit C40 and the calculation unit C60. In the calculation unit C60, the brake requested torque Tr2 corresponding to the depression amount of the brake pedal obtained from the brake sensor 72 is compared with the target coast torque Ttc, and the larger one of these is output. The torque obtained from the calculation unit C60 is distributed by the calculation unit C70 into the regenerative coordination torque Tcr and the hydraulic brake torque Tb. Information on the hydraulic brake torque Tb distributed in this way is transmitted to the B-ECU 50 for control of the hydraulic brake device 7.

[0049] On the other hand, in the calculation unit C40, the target coast torque Ttc obtained by the calculation unit C30 is subtracted from the driver requested torque Tr1 obtained by the calculation unit C10, and is calculated as the post-coast-distribution requested torque Tr3. Further, the post-coast-distribution requested torque Tr3 is added by the calculation unit C50 to the regenerative coordination torque Tcr distributed by the calculation unit C70, and is calculated as the post-regenerative-coordination-reflection requested torque Tr4. This post-regenerative-coordination-reflection requested torque Tr4 is output to the calculation unit C80, and the requested torque for each component is calculated by reflecting 4WD control. Note that the requested torque for each component includes a front motor requested torque Trf for controlling the front motor 3F, a rear motor requested torque Trr for controlling the rear motor 3R, a regeneration requested torque Trc for controlling the second electric motor, and the like, and each requested torque is transmitted to the PDU 30, RMCU 40, and the like for respective control.

[0050] Here, we will further explain the calculation of the driver-requested torque Tr1. Figure 5 is a block diagram illustrating the details of the calculation process for the driver-requested torque Tr1 in the calculation unit C10 shown in Figure 4. In Figure 5, characteristic processing systems are indicated by dotted and dashed lines. As shown in Figure 5, first, the calculation unit C11 sets the accelerator-requested torque Tr0 according to the vehicle speed and accelerator opening (APS) of the vehicle 1 for each of the normal mode and i-Pedal mode one-pedal mode (i.e., for each mode). Specifically, the primary value X1 of the accelerator-requested torque is calculated using a map according to the vehicle speed and accelerator opening (APS). This map is prepared according to each combination of the selected shift mode, the selected drive mode, and the on / off state of the i-Pedal mode, and is used according to each mode state.

[0051] The calculated primary accelerator request torque X1 is used when switching between i-Pedal mode (one-pedal mode) and normal mode. The calculation unit C12 performs a process to limit the rate of change (amount of change per unit time) of the primary accelerator request torque X1. In i-Pedal mode, the accelerator request torque Tr0 is set to a negative value in the region where the accelerator opening is small, whereas in normal mode, the accelerator request torque Tr0 is set to a positive value if the accelerator is operated even in the region where the accelerator opening is small. Therefore, when switching between the two modes, the accelerator request torque Tr0 can change significantly. In this case, a process is performed to limit the rate of change (amount of change per unit time) of the primary accelerator request torque X1 to suppress sudden changes in the accelerator request torque. Details of the rate of change limiting process in the calculation unit C12 will be described later.

[0052] Thus, the torque value Ths, which is the primary value of accelerator-requested torque X1 with rate of change limiting applied (torque after rate of change limiting), is output to the calculation unit C13 along with the torque value that is not subject to rate of change limiting (i.e., the primary value of accelerator-requested torque X1). When the above mode switching occurs, mode switching determination information is input to the calculation unit C13, and based on this information, the torque value X3 after rate of change limiting is output. Specifically, if a mode switching determination is made, the torque value Ths after rate of change limiting is selected and output as the torque value X3, and if a mode switching determination is not made, the primary value of accelerator-requested torque X1 is selected and output as the torque value X3.

[0053] The torque value X3 output from the calculation unit C13 is filtered by the LPF (low-pass filter) C14. The resulting accelerator request torque Tr0 is output to the calculation unit C15. The calculation unit C15 receives the paddle correction torque Tpa and creep torque Tc corresponding to the operation of the paddle shift 77 as input, and the sum of these three values ​​Tr0, Tpa, and Tc is calculated as the driver request torque Tr1.

[0054] Next, we will explain the configuration specific to this control system 10 regarding the rate of change limiting process of the calculation unit C12 and the processing of the paddle correction torque input to the calculation unit C15.

[0055] In the rate of change limiting process of the calculation unit C12, an upper limit restriction is applied when the primary accelerator request torque X1 changes to an increasing value, and a lower limit restriction is applied when the primary accelerator request torque X1 changes to a decreasing value. The primary accelerator request torque X1 is used in the calculation of the driver request torque Tr1 after undergoing various processes as described later. If the primary accelerator request torque X1 is used directly in the calculation of the driver request torque Tr1, a sudden change in the primary accelerator request torque X1 will also cause a sudden change in the driver request torque Tr1, leading to a sudden change in the driving torque of vehicle 1. Therefore, processing is performed to suppress the rate of change of the primary accelerator request torque X1. In either case (i.e., both upper and lower limit restrictions), it is common logic to always use a constant limit rate of change (limit of the amount of change per unit time) to suppress the change in the accelerator request torque Tr0.

[0056] In contrast, the torque setting unit 21 of the higher-level ECU 20, as shown by the dotted line, uses a change rate limiting unit 23 to feed back the previous value of the driver-requested torque Tr1, and sets the absolute value of the limit change rate when the driver-requested torque Tr1 is negative to a value greater than the absolute value of the limit change rate when the driver-requested torque Tr1 is positive. Hereinafter, this will be referred to as "first control". Note that "1 / Z" in the figure indicates the previous value.

[0057] Thus, the absolute value of the limit change rate when the driver-requested torque Tr1 is a negative value is set to be larger than the absolute value of the limit change rate when the driver-requested torque Tr1 is positive for the following reasons. The inventors of this case considered specific situations in which excessive deceleration temporarily occurs in vehicle 1 when switching from i-Pedal mode to normal mode. As a result, it was found that the above-mentioned excessive deceleration occurs when i-Pedal mode is selected, and the accelerator pedal is being released (i.e., during deceleration driving with the accelerator off), and the driver's foot is on the brake pedal, and the i-Pedal mode is switched off (to normal mode).

[0058] The reason for this is that when the mode is changed, not only is the rate of change limited for sudden changes in the driver-requested torque Tr1, but the target coast torque lower limit TtcL used in the calculation unit C20 also changes abruptly from a large absolute value (for example, -3000 to -2000 [Nm]) to 0 [Nm]. Therefore, in order to suppress this abrupt change, the rate of change of the target coast torque lower limit TtcL is also limited.

[0059] To minimize abrupt changes in the target coasting torque lower limit TtcL, it is effective to strengthen the limit on the rate of change of the target coasting torque lower limit TtcL, that is, to reduce the limit rate of change. However, in the case of mechanical brake systems such as the hydraulic brake system 7, it is difficult to achieve fine-grained control, and the limit rate of change of the target coasting torque lower limit TtcL must be set to a larger value. On the other hand, it is easy to achieve fine-grained control of the driver-requested torque instructed to the electrically controlled motor 3. Therefore, the limit rate of change of the driver-requested torque Tr1 is set to be smaller than the limit rate of change of the target coasting torque lower limit TtcL.

[0060] When the relative magnitudes of the limit change rates are set in this way, when switching from i-Pedal mode to normal mode, the target coasting torque lower limit TtcL increases from a large absolute value (e.g., -3000 to -2000 [Nm]) to 0 [Nm] at a relatively large limit change rate (since it is a negative value, the absolute value decreases), while the accelerator request torque Tr0 increases at a relatively small limit change rate (since it is a negative value, the absolute value decreases). As a result, the target coasting torque lower limit TtcL may become larger than the accelerator request torque Tr0, and the calculation unit C20 in Figure 4 outputs the target coasting torque lower limit TtcL as the target coasting torque Ttc. This target coasting torque Ttc is then used for subtraction in the calculation unit C40 in Figure 4, causing the coasting distribution request torque Tr3 to drop sharply. If the foot remains on the brake pedal, the sharp drop in the coasting distribution request torque Tr3 will result in excessive deceleration of vehicle 1. Furthermore, these issues do not occur when the driver-required torque Tr1 is positive; therefore, only when the driver-required torque Tr1 is negative should the limit change rate be adjusted accordingly.

[0061] The above explains why the absolute value of the limit change rate when the driver-requested torque Tr1 is a negative value is set to be greater than the absolute value of the limit change rate when the driver-requested torque Tr1 is positive. Therefore, the change rate limiting unit 23 feeds back the previous value of the driver-requested torque Tr1 and sets the absolute value of the limit change rate when the driver-requested torque Tr1 is a negative value to be greater than the absolute value of the limit change rate when the driver-requested torque Tr1 is positive.

[0062] Specifically, in the calculation units C12a and C12b shown by dotted lines in Figure 5, maps (horizontal axis: driver-requested torque Tr1, vertical axis: limit change rate) are pre-defined with the driver-requested torque Tr1 as an argument. Note that the right side of the horizontal axis is positive, the top side of the vertical axis is positive, and the intersection of the horizontal and vertical axes is 0. The map in calculation unit C12a is the upper limit map of the change rate and is used when setting the limit change rate when the driver-requested torque Tr1 increases. The map in calculation unit C12b is the lower limit map of the change rate and is used when setting the limit change rate when the driver-requested torque Tr1 decreases. In these maps, when the driver-requested torque Tr1 is a negative value, the absolute value (magnitude) of the limit change rate is set to be large, and when the driver-requested torque Tr1 is a positive value, the absolute value (magnitude) of the limit change rate is set to be small. Also, when the driver-requested torque Tr1 is near 0, the absolute value (magnitude) of the limit change rate changes linearly. The rate of change limiting unit 23 uses such a map to set a limit rate of change based on the previous driver-requested torque Tr1.

[0063] Here, the rate of change limit when the driver-requested torque Tr1 is a negative value is set to be approximately the same as the rate of change limit of the target coast torque lower limit TtcL. This prevents the target coast torque lower limit TtcL from becoming greater than the accelerator-requested torque Tr0, avoids a sharp drop in the coast-distributed requested torque Tr3, and prevents excessive deceleration of vehicle 1.

[0064] Meanwhile, in the calculation unit C15, the paddle correction torque Tpa corresponding to the operation of the paddle shift 77 and the creep torque Tc are added together to calculate the driver-requested torque Tr1. Therefore, driver-requested torque Tr1 = accelerator-requested torque Tr0 + creep torque Tc + paddle correction torque Tpa. However, during deceleration, the creep torque Tc = 0, so the sum of the accelerator-requested torque Tr0 and the paddle correction torque Tpa becomes the driver-requested torque Tr1.

[0065] Regarding the paddle correction torque Tpa, the paddle correction torque calculation unit C16 calculates the paddle correction torque Tpa according to the regenerative levels B0 to B5 based on the paddle signal (operation signal of the paddle shift 77). Normally, the calculated paddle correction torque Tpa is output directly to the calculation unit C15 to calculate the driver-requested torque Tr1, so when the paddle shift 77 is changed, the driver-requested torque Tr1 changes in a step-like manner. This step-like change will immediately increase the deceleration of the vehicle 1. However, this is in response to the driver's change operation, and since the paddle shift 77 is changed one step at a time, it does not result in sudden deceleration, and the driver does not feel any discomfort.

[0066] On the other hand, when the drive mode is Power mode or Tarmac mode (i.e., Sport mode), if there is a mode switch from i-Pedal mode to normal mode, the shift range changes abruptly from the D range regenerative level (equivalent to regenerative level B2 in this embodiment) to regenerative level B5. Moreover, since this change does not correspond to the driver's operation to change the regenerative level, it can cause a sudden deceleration of the vehicle 1, which can easily cause a significant sense of discomfort. Therefore, the addition limiting unit 24 according to the drive mode performs paddle correction limiting, which limits the addition of the paddle correction torque Tpa in the calculation unit C15. Hereinafter, this will be referred to as "second control".

[0067] Specifically, as shown in Figure 5, the paddle correction torque calculated by the paddle correction torque calculation unit C16 (hereinafter referred to as "paddle correction torque primary value X2") and the accelerator request torque primary value X1 calculated by the calculation unit C11 are input to the calculation unit C17a and added together. This added value is output to the calculation unit C17b. In the calculation unit C17b, the torque value X3 output from the calculation unit C13 is subtracted from this added value. The subtracted value X4 (= X1 + X2 - X3) calculated by the calculation unit C17b is compared with the value 0 in the calculation unit C17c, and the smaller value is selected and output. Note that the calculation unit C17c outputs this value as long as the torque value of the subtracted value X4 is negative. Then, the value output from the calculation unit C17c is compared with the paddle correction torque primary value X2 in the calculation unit C17d, and the larger value is selected as the addition limit correction torque X5 and output to the calculation unit C18.

[0068] When the drive mode is in sport mode, the calculation unit C18 receives paddle correction limit determination information (information indicating that paddle correction limit should be applied). Furthermore, the calculation unit C18 receives the addition limit correction torque X5 and the primary value of the paddle correction torque X2 input from the calculation unit C17d, and based on this information, the paddle correction torque Tpa is output to the calculation unit C15. Specifically, if the paddle correction limit determination information is input to the calculation unit C18, the addition limit correction torque X5 is output as the paddle correction torque Tpa, and if the paddle correction limit determination information is not input, the primary value of the paddle correction torque X2 is output as the paddle correction torque Tpa.

[0069] When paddle correction limiting is enabled, the primary accelerator request torque X1 increases in a step-like manner when switching from i-Pedal mode to normal mode. However, since the torque value X3, whose rate of change is limited by the calculation unit C12, increases gradually, the primary accelerator request torque X1 will be greater than the torque value X3 until the rate of change limiting is completed. Therefore, the subtracted value X4 will be greater than the primary paddle correction torque X2, and the calculation unit C17d will select the subtracted value X4 and output it to the calculation unit C13 until the rate of change limiting is completed. This avoids a step-like torque decrease due to the addition of the paddle correction torque Tpa, and prevents sudden deceleration of the vehicle 1. The torque setting unit 21 will continue to limit the addition of the paddle correction torque Tpa by the addition limiting unit 24 until the accelerator request torque Tr0 converges.

[0070] Finally, the first and second control systems will be explained using the time charts in Figures 6 and 7. Although not shown in Figures 6 and 7, symbols indicating parameters are included in the following explanation to make the relationship with the parameters explained in Figures 4 and 5 easier to understand. Figure 6 shows the time changes of vehicle speed, brake pedal stroke (amount of brake pedal depression), i-Pedal mode SW76 on / off state, accelerator request torque Tr0, target coast torque Ttc, coast distribution request torque Tr3, regenerative coordination torque Tcr, and regenerative coordination reflected request torque Tr4, as shown in (a) to (h). Figure 7 shows the time changes of vehicle speed, i-Pedal mode SW76 on / off state, paddle shift 77 state, accelerator request torque Tr0, paddle correction torque Tpa, and driver request torque Tr1, as shown in (a) to (f).

[0071] Let's explain the first control. In the example shown in Figure 6, while decelerating with the accelerator off and the foot on the brake pedal (constant brake pedal stroke), a mode switch from i-Pedal mode to normal mode occurs at time t1 (see <1>). Although the accelerator-required torque Tr0 in the accelerator-off state is negative in both cases, it is higher in normal mode than in i-Pedal mode, so the accelerator-required torque Tr0 increases, but the rate of change is limited to avoid abrupt changes.

[0072] At this time, if the limit on the rate of change is strengthened, that is, if the limit rate of change is reduced, the accelerator-requested torque Tr0 will rise gradually, as shown by the dashed line in Figure 6(d) (see <2>). On the other hand, the target coast torque lower limit TtcL rises relatively quickly because the limit rate of change is large, as shown by the thick dashed line in Figure 6(e) (see <3>), and the target coast torque Ttc also rises in accordance with the target coast torque lower limit TtcL. As a result, at time t2, the target coast torque lower limit TtcL exceeds the accelerator-requested torque Tr0, and the target coast torque Ttc also rises in accordance with the target coast torque lower limit TtcL. Consequently, from this time t2, the coast-distribution-based requested torque Tr3 drops sharply, as shown by the dashed line in Figure 6(f) (see <4>). Also, the regenerative-coordinate-reflected requested torque Tr4 also decreases, as shown by the dashed line in Figure 6(h) (see <5>).

[0073] The decrease in the requested torque Tr3 after coast distribution and the requested torque Tr4 after regenerative coordination reflection continues until the target coast torque Ttc reaches its target value (let's call this time t3), after which they recover (increase), and the requested torque Tr4 after regenerative coordination reflection returns to its final target value at time t4 when the target coast torque Ttc reaches a value of 0, and the requested torque Tr3 after coast distribution returns to its final target value at time t5 when the accelerator requested torque Tr0 reaches its target value. Thus, the conventional method of reducing the limit change rate of the accelerator requested torque Tr0 leads to excessive deceleration of vehicle 1 due to the rapid decrease in torque.

[0074] In contrast, in this control system 10, if the limit on the rate of change of the accelerator request torque Tr0 is weakened, that is, if the limit rate of change is increased, the accelerator request torque Tr0 will rise relatively quickly, as shown by the solid line in Figure 6(d), and the lower limit of the target coast torque TtcL will not exceed the accelerator request torque Tr0. This prevents a sharp drop in the coast request torque Tr3 after distribution and a drop in the regenerative coordination request torque Tr4 after reflection. Therefore, by avoiding a sharp drop in torque, excessive deceleration of the vehicle 1 is also prevented.

[0075] In the second control case, the drive mode is sport mode, and a mode switch is performed from i-Pedal mode to normal mode. In the example shown in Figure 7, the vehicle is decelerating with the accelerator off [see Figure 7(a)]. When the drive mode is sport mode, at time t11, when the mode is switched from i-Pedal mode to normal mode [see in Figure 7(b)], the paddle shift 77 automatically shifts the regenerative level from D range (corresponding to regenerative level B2 in this embodiment) to regenerative level B5 in one go.

[0076] The shift in regenerative torque at this time, i.e., the paddle-corrected torque Tpa, drops sharply, as shown by the dashed line in Figure 7(e). If the paddle-corrected torque Tpa is used directly in the calculation of the driver-requested torque Tr1, the driver-requested torque Tr1 also drops instantaneously in a step-like manner, as shown by the dashed line in Figure 7(f). Conventionally, this sharp drop in torque has led to excessive deceleration of vehicle 1.

[0077] In contrast, the addition limiting unit 24 of this control system 10 limits the paddle correction torque Tpa in the calculation unit C15 to a value of 0, thereby avoiding a sharp drop in torque due to the paddle correction torque Tpa and preventing excessive deceleration of the vehicle 1. Even if the addition limiting unit 24 limits the addition of the paddle correction torque Tpa at time t11, the driver-requested torque Tr1 increases in accordance with the increase in the accelerator-requested torque Tr0. Then, from time t12 [see in Figure 7(d)], when the accelerator-requested torque Tr0 exceeds the torque equivalent to regenerative level B5, the limit on the addition of the paddle correction torque Tpa is gradually weakened. From this point onward, the driver-requested torque Tr1 remains constant as the torque decrease due to the paddle correction torque Tpa and the torque increase due to the accelerator-requested torque Tr0 cancel each other out. Subsequently, at time t13, when the accelerator-requested torque Tr0 and the paddle correction torque Tpa converge to their respective target torques, the addition limiting unit 24 ends.

[0078] [3. Operation and Effects] (1) In the control system 10 described above, the rate of change limiting unit 23 of the torque setting unit 21 limits the rate of change of the driver-requested torque to within the limit rate of change when there is a mode switch from i-Pedal mode to normal mode. At this time, the absolute value of the limit rate of change when the driver-requested torque is negative is set to be larger than the absolute value of the limit rate of change when the driver-requested torque is positive, so a sudden drop in the driver-requested torque caused by a small limit rate of change immediately after mode switching can be avoided. As a result, even if the driver's foot remains on the brake pedal which was pulled in in i-Pedal mode before and after mode switching, a sudden drop in the driver-requested torque can be avoided, and excessive deceleration of the vehicle 1 can be suppressed. Therefore, it contributes to improving the driving feeling and ride comfort.

[0079] (2) According to the control system 10 described above, the limit change rate is obtained using a map with the driver-requested torque as an argument, so the limit change rates for both the case where the driver-requested torque is negative and the case where the driver-requested torque is positive can be obtained simply and reliably.

[0080] (3) In the control system 10 described above, the addition limiting unit 24 of the torque setting unit 21 limits the addition of paddle correction torque when setting the driver-requested torque when the mode is switched from i-Pedal mode to normal mode while sport mode is selected. This prevents a sudden drop in the driver-requested torque caused by the automatic increase in paddle correction torque (increase in regeneration level) during mode switching. Consequently, it also prevents excessive temporary deceleration of the vehicle 1 caused by this, contributing to further improvements in driving feel and ride comfort.

[0081] (4) As with the vehicle 1 described above, if the regenerative level to which the paddle correction torque is automatically increased is set to the maximum level (regenerative level B5 in this embodiment), the sudden drop in the driver-required torque that occurs when switching modes tends to be more pronounced. As a result, the deceleration of the vehicle 1 tends to be excessive, but the control system 10 described above can avoid the occurrence of such phenomena.

[0082] (5) In the control system 10 described above, the torque setting unit 21 calculates a subtracted value X4 by subtracting the torque value X3 after limiting the rate of change of the accelerator request torque from the sum of the primary accelerator request torque value X1 (value before limiting the rate of change of the accelerator request torque) and the primary paddle correction torque value X2 (regenerative correction torque). The smaller of the subtracted value X4 and the value 0, and the larger of the value X2, is set as the addition limit correction torque X5, and the addition of this addition limit correction torque X5 to the accelerator request torque is set as the driver request torque. This calculation method ensures that the addition of paddle correction torque when setting the driver request torque is limited. Therefore, it is possible to suppress the occurrence of excessive deceleration in the vehicle 1, which contributes to improving the driving feeling and ride comfort.

[0083] (6) According to the control system 10 described above, the torque setting unit 21 limits the addition of paddle correction torque until the accelerator request torque converges, thereby reliably suppressing sudden changes in paddle correction torque. Therefore, it is possible to suppress the occurrence of excessive deceleration in the vehicle 1, which contributes to an improvement in driving feel and ride comfort.

[0084] [4. Others] The control system 10 described above is an example and is not limited to the configuration described above. Also, the vehicle 1 to which the control system 10 is applied is not limited to the configuration shown in Figure 1. In the above embodiment, a first control and a second control are performed. That is, the first control takes measures to prevent excessive deceleration in the vehicle 1 caused by limiting the rate of change of the driver-requested torque when switching from i-Pedal mode to normal mode during deceleration driving with the accelerator off. The second control takes measures to prevent excessive deceleration in the vehicle 1 caused by the automatic change of the regenerative level (paddle correction torque) in the same situation. However, the control system 10 only needs to perform the first control and the second control may be omitted.

[0085] Furthermore, the drive modes shown in Figure 3 are just examples, and any of them may be omitted, or other modes may be provided. Also, in the vehicle 1 described above, the front motor 3F, generator 4, engine 5, and transaxle 6 are provided on the front side, and the rear motor 3R is provided on the rear side, but the configuration of the front and rear may be reversed, or either one may be omitted.

[0086] The maps shown in Figure 5 (upper limit map of the rate of change, lower limit map of the rate of change) are just one example. In this map, the limit rate of change is set to a constant value when the driver's requested torque is far from zero, but the limit rate of change may be set to a value that changes according to the driver's requested torque. Also, the maps shown in Figure 5 have characteristics that are symmetrical with respect to the horizontal axis, but the upper limit map and the lower limit map do not have to have such characteristics.

[0087] This technology is applicable to the manufacturing industry of electric vehicles, including electric vehicles and hybrid electric vehicles.

[0088] 1 Vehicle 3 Motors (First motor, Second motor) 3F Front motor (First motor, Second motor) 3R Rear motor (First motor, Second motor) 4 Generator (Second motor) 7 Hydraulic brake system (Mechanical brake system) 10 Control system 20 Higher-level ECU (PHEV-ECU) 21 Torque setting unit 22 Control unit 23 Rate of change limiting unit 24 Addition limiting unit 71 Accelerator opening sensor 72 Brake sensor 73 Shift position sensor 74 Vehicle speed sensor 75 Drive mode selector (Drive mode selection switch) 76 i-Pedal mode SW (One-pedal mode selection switch) 77 Paddle shift (Regenerative level selection switch) Tr0 Accelerator requested torque Tr1 Driver requested torque X1 Primary value of accelerator requested torque X2 Primary value of paddle correction torque X3 Torque value after limiting the rate of change X4 Subtraction value (X1 + X2 - X3) X5 Correction torque for addition limit

Claims

1. A control system provided for a vehicle equipped with a first motor for driving and a second motor capable of generating electricity from inertial energy, which can implement a normal mode in which acceleration control is performed by operating the accelerator pedal and deceleration control is performed by operating the brake pedal, and a one-pedal mode in which acceleration and deceleration control is performed by operating only the accelerator pedal, wherein when the one-pedal mode is selected, the system is configured to automatically move the brake pedal to the depressed side in conjunction with the operation of a mechanical brake device when the accelerator pedal is released during deceleration operation, and in each of the normal mode and the one-pedal mode, the system comprises a torque setting unit that sets a driver-requested torque from an accelerator-requested torque set according to the vehicle speed and the amount of operation of the accelerator pedal, and a control unit that controls the operation of at least one of the first motor, the second motor and the brake device according to the set driver-requested torque, wherein the torque setting unit has a change rate limiting unit that limits the rate of change of the driver-requested torque to within a limit change rate when switching modes from the one-pedal mode to the normal mode. A vehicle control system characterized in that the absolute value of the limit change rate when the driver-requested torque is negative is greater than the absolute value of the limit change rate when the driver-requested torque is positive.

2. The vehicle control system according to claim 1, characterized in that the rate of change limiting unit acquires the limit rate of change using a map with the driver-requested torque as an argument.

3. A vehicle control system according to claim 1 or 2, comprising: a regenerative level selection switch operated when selecting one of several regenerative levels for the magnitude of regenerative braking using the second electric motor as a power generation load; a drive mode selection switch operated when selecting one of several drive modes, including a normal mode, an eco mode prioritizing fuel efficiency, and a sport mode prioritizing driving performance; wherein when the one-pedal mode is selected, the operation of the regenerative level selection switch is disabled, and when the normal mode is selected, the operation of the regenerative level selection switch is enabled; when the sport mode is selected as the drive mode, a predetermined regenerative level with a high degree of regeneration is automatically selected from several regenerative levels; the torque setting unit sets the driver-requested torque as the accelerator-requested torque plus a correction torque corresponding to the regenerative level when the regenerative level is selected; and the torque setting unit has an addition limiting unit that limits the addition of the correction torque when setting the driver-requested torque during mode switching.

4. The vehicle control system according to claim 3, characterized in that the predetermined regenerative level is the maximum level at which the regenerative brake level is highest.

5. The vehicle control system according to claim 4, characterized in that the torque setting unit calculates a subtracted value by subtracting the value after the rate of change of the accelerator request torque is limited from the sum of the value before the rate of change of the accelerator request torque is limited and the correction torque, sets the larger of the smaller of the subtracted value and the value of 0 and the correction torque as the addition limit correction torque, and sets the driver request torque to the accelerator request torque plus the addition limit correction torque.

6. The vehicle control system according to claim 5, characterized in that the torque setting unit limits the addition of the correction torque until the accelerator request torque converges.

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