Vehicle control device

Abstract

To provide a vehicle control device capable of changing a shift range to an N range while suppressing the occurrence of shock even an automatic-return-type shift lever is operated to an N position for a short time.SOLUTION: A vehicle 10 includes an automatic-return-type shift lever 42 that is to be operated to change a shift range. When a shift range is a D range, the vehicle is running under a regenerative control, and when the shift lever 42 is held at an N position for a duration longer than or equal to a predetermined held time period Phld, an electric control device 90 of the vehicle 10 executes, for a predetermined control time period Pctrl, a braking force cooperative control that progressively reduces regenerative torque Tmg and progressively increases wheel brake torque Twb, and then changes the shift range to an N range.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with an automatic return type operator that is operated to switch a shift range. [Background technology]

[0002] When the shift lever is switched from the D position, which selects the D range (= forward driving range), to the N position, which selects the N range (= neutral range) during regenerative control, the twist in the rotational direction of the axle, etc., caused by the regenerative torque is suddenly released by switching the shift range, causing a shock. In order to suppress the occurrence of this shock, a vehicle control device is known that executes a braking force cooperative control in which the regenerative torque is gradually reduced in advance and the wheel brake torque is gradually increased when the shift lever is switched from the D position to the N position. For example, the device described in Patent Document 1 is one such device. Patent Document 1 discloses a technology in which, when the shift lever is operated from the D position to the N position, during the period in which the shift lever is operated to the N position, a braking force cooperative control is executed in which the regenerative torque is gradually reduced in advance and the wheel brake torque is gradually increased, thereby suppressing the occurrence of a shock. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-90444 A Summary of the Invention [Problem to be solved by the invention]

[0004] Unlike the configuration described in Patent Document 1, there is known a so-called shift by wire type shift operation device in which the shift lever is of an automatic return type. In such a shift operation device, when the driver operates the shift lever from the initial position, H position, to the N position and holds it there, similarly to Patent Document 1, during the period when the shift lever is held at the N position, it is considered that the occurrence of shocks is suppressed by executing a braking force cooperative control that gradually reduces the regenerative torque and gradually increases the wheel brake torque in advance.

[0005] Incidentally, in an automatic return type shift operation device, there is a short-term N operation in which the driver operates the shift lever from the H position to the N position in order to switch the shift range to the N range, and then immediately returns it to the H position. The "short-term N operation" is an operation in which the shift lever is held in the N position for a predetermined holding period or longer and then immediately returned to the H position. Here, if the predetermined holding period is set long, the driver must continue to hold the shift lever for a long period in order to switch the shift range to the N range, which becomes a cumbersome operation for the driver. On the other hand, if the predetermined holding period is set short, the period during which the shift lever is operated to the N position and held there is short, and there is not enough time to reduce the regenerative torque, which may cause a shock.

[0006] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can switch the shift range to N range while suppressing the occurrence of shock even if an automatic return type shift lever is operated to the N position for a short period of time. [Means for solving the problem]

[0007] The gist of the present invention is a control device for a vehicle equipped with an automatic return type operator that is operated to change the shift range, wherein when the shift range is in the driving range and the operator is held in the N position that selects the N range for a predetermined first period or more while the vehicle is traveling and under regenerative control, a braking force cooperative control that gradually reduces regenerative torque and gradually increases wheel brake torque is executed for a predetermined second period, and then the shift range is switched to the N range. Effect of the Invention

[0008] According to the vehicle control device of the present invention, when the shift range is in the driving range and the operator is held at the N position selecting the N range for a predetermined first period or more during regenerative control, a braking force cooperative control that gradually reduces the regenerative torque and gradually increases the wheel brake torque is executed for a predetermined second period, and then the shift range is switched to the N range. In this way, the regenerative torque is gradually reduced by the braking force cooperative control executed for the predetermined second period. After the predetermined second period has elapsed, the twisting of the power transmission path caused by the regenerative torque is sufficiently reduced, so that the occurrence of shock is suppressed even when the shift range is switched to the N range. Therefore, even if the shift lever is operated to the N position for a short period of time, the shift range is switched to the N range while the occurrence of shock is suppressed. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the vehicle. [Diagram 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. [Diagram 3] 3 is an example of a time chart when the flowchart of FIG. 2 is executed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0011] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of the control functions for various controls in the vehicle 10.

[0012] The vehicle 10 is equipped with an engine 12 and an electric motor MG, which are power sources for traveling, and a power transmission device 16 provided in a power transmission path PT between the engine 12 and a pair of drive wheels 14. The vehicle 10 also includes a shift operation device 40, an indicator 50, a hydraulic control circuit 60, an inverter 62, a battery 64, and an electronic control device 90.

[0013] The engine 12 is a known internal combustion engine. An engine torque Te [Nm], which is an output torque of the engine 12, is controlled by an electronic control device 90. The electric motor MG is, for example, a so-called motor generator having a function as an electric motor (i.e., a motor function) and a function as a generator (i.e., a generator function). The electric motor MG is, for example, a three-phase synchronous motor.

[0014] The power transmission device 16 includes, in order from the engine 12 side, an engine connecting shaft 30, a clutch K0, an electric motor connecting shaft 32, a torque converter 20, an input shaft 34 which is an input rotating member of the automatic transmission 22, the automatic transmission 22, etc., in a case 18, and also includes an output shaft 36 which is an output rotating member of the automatic transmission 22, a differential 24, a pair of axles 38, etc., all of which are well known in the art. The case 18 is a non-rotating member attached to the vehicle body. The clutch K0 is a friction engagement device that connects and disconnects the power transmission between the engine connecting shaft 30 connected to the engine 12 and the electric motor connecting shaft 32 connected to the rotor of the electric motor MG, and is, for example, a wet-type multi-plate hydraulic friction engagement device. In this specification, unless otherwise specified, the terms torque, driving force, power, and force (power) are synonymous.

[0015] The automatic transmission 22 is a well-known automatic transmission, such as a planetary gear type or a constant meshing parallel shaft type. The automatic transmission 22 is controlled by a hydraulic control circuit 60 controlled by an electronic control device 90 so that a desired gear ratio γat is formed from among different gear ratios γat. The gear ratio γat is the rotational speed ratio (=Nin / Nout) between the input shaft rotational speed Nin [rpm] and the output shaft rotational speed Nout [rpm]. The input shaft rotational speed Nin is the rotational speed of the input shaft 34, and the output shaft rotational speed Nout is the rotational speed of the output shaft 36.

[0016] The hydraulic control circuit 60 uses, for example, hydraulic oil discharged by an oil pump 68 as the source pressure, and supplies regulated hydraulic pressure to an actuator that performs engagement / disengagement control of the lock-up clutch LU of the torque converter 20 and an actuator that performs gear shift control of the automatic transmission 22.

[0017] The shift operation device 40 is an operation device for selecting one of a plurality of shift ranges. In other words, the shift operation device 40 is an operation device that is manually operated to receive a request to switch the shift range. The shift operation device 40 is disposed, for example, near the driver's seat, and has an operator that is selectively operated by the driver to a plurality of operation positions corresponding to the plurality of shift ranges. The shift range indicates a power transmission state from the engine 12 and the electric motor MG, which are the power sources for traveling, to a pair of drive wheels 14, and includes, for example, an R range, an N range, a D range, a P range, etc., which will be described later.

[0018] The shift operation device 40 employs a so-called shift-by-wire system. The shift operation device 40 includes, for example, a shift lever 42 and a P switch 46. The shift lever 42 and the P switch 46 are both momentary type operators that are returned to their original positions (initial positions) when no external force is applied. In other words, the shift lever 42 and the P switch 46 are operators that are returned to their initial positions when not operated by the driver (in other words, automatic return type operators that automatically return to their initial positions when the operating force is released). The shift lever 42 corresponds to the "operator" in this invention.

[0019] The operating positions of the shift lever 42 are, for example, "H position", "R position", "N position", "D position", and "B position". The "H position" is the initial position (home position) of the shift lever 42. Even if the shift lever 42 is operated to an operating position other than the "H position", if the driver releases the shift lever 42 (i.e., if the external force acting on the shift lever 42 is no longer applied), the shift lever 42 is returned to the "H position" by a mechanical mechanism such as a spring. The "R position" is an operating position that selects the R range that allows the vehicle 10 to travel backward. The "N position" is an operating position that selects the N range, which is a neutral state in which power transmission from the power source for traveling to the pair of drive wheels 14 is cut off. For example, in the N range, the automatic transmission 22 is in a neutral state. The "D position" is an operating position that selects the D range that allows the vehicle 10 to travel forward. The "B position" is an operating position for selecting a decelerated forward driving state in which engine braking using the engine 12 is more likely to be applied (i.e., a state in which the engine braking effect is stronger) when a power transmission path PT for forward driving is formed by operating to the "D position".

[0020] The P switch 46 is, for example, a momentary push button switch, and when the driver presses it, a neutral state is set in which the power transmission from the driving power source to the pair of driving wheels 14 is cut off, and the pair of driving wheels 14 is mechanically fixed so as not to rotate, thereby selecting a P range (=parking range). When the P switch 46 is not pressed, the P switch 46 is set to its initial position (home position), and even if the P switch 46 is pressed, if the driver releases the P switch 46, the P switch 46 is returned to the initial position by a mechanical mechanism such as a spring. The "D range" and "R range" are driving ranges, and the "P range" and "N range" are non-driving ranges. The "N range" and "D range" correspond to the "N range" and "driving range" in the present invention, respectively.

[0021] Corresponding to the shift ranges P, R, N, and D, the automatic transmission 22 is controlled to each of the P range, in which the power transmission state is neutral and the output shaft 36 connected to the pair of drive wheels 14 is mechanically fixed so as not to rotate, the R range, in which the power transmission state enables reverse driving, the N range, in which the power transmission state is neutral, and the D range, in which the power transmission state enables forward driving.

[0022] The indicator 50 is provided in a position that is easily visible to the driver, and indicates the selected shift range. The indicator 50 may, for example, indicate the actual power transmission state of the automatic transmission 22. In the shift operation device 40 of this embodiment, the shift lever 42 and the P switch 46 are returned to their initial positions when the external force acting thereon is removed, so the driver cannot recognize the selected shift range by simply looking at the shift lever 42 and the P switch 46. Therefore, it is useful to provide such an indicator 50.

[0023] The inverter 62 is a power supply circuit that converts DC to AC and AC to DC. The MG torque Tmg [Nm], which is the output torque of the electric motor MG, is controlled by the electronic control device 90 via the inverter 62. When the MG torque Tmg is a positive value, the MG torque Tmg acts as a power source for running the vehicle 10. When the MG torque Tmg is a negative value, the MG torque Tmg is a regenerative torque and acts as a braking force for decelerating the vehicle 10. Hereinafter, the negative value of the MG torque Tmg (<0) will be referred to as the "regenerative torque Tmg". The determination of the magnitude of the regenerative torque Tmg means the determination of the magnitude of the absolute value of the regenerative torque Tmg. For example, when the regenerative torque Tmg (<0) approaches zero, it is described as "the regenerative torque Tmg becomes smaller", and when the regenerative torque Tmg moves away from zero, it is described as "the regenerative torque Tmg becomes larger".

[0024] The battery 64 is a secondary battery for driving the electric motor MG.

[0025] The vehicle 10 includes a wheel brake device 26 as a braking device that applies a braking torque by a wheel brake torque Twb [Nm] (<0) to the wheels (a pair of driving wheels 14 and a pair of driven wheels not shown). The wheel brake device 26 is a well-known electronic control brake. The wheel brake device 26 includes a brake main body 26a and a braking hydraulic pressure supply circuit 26b. The brake main body 26a is a so-called disk brake in which, for example, a pair of axles 38 connected to the pair of driving wheels 14 and a pair of axles connected to the pair of driven wheels not shown are sandwiched between brake pads to obtain a braking force by the frictional force. The braking hydraulic pressure supply circuit 26b supplies a brake hydraulic pressure (also called a brake braking hydraulic pressure) to a wheel cylinder provided in the brake main body 26a according to a brake operation amount Bra [%] by, for example, a brake pedal operation by the driver. The braking hydraulic pressure supply circuit 26b is a hydraulic actuator. In electronically controlled brakes, an optimal ratio of braking force for each wheel is calculated, and the braking force for each wheel is controlled so as to achieve that ratio.

[0026] Normally, brake hydraulic pressure is supplied to the wheel cylinder so that the wheel brake torque Twb by the wheel brake device 26 becomes a braking force of a magnitude corresponding to the brake operation amount Bra. On the other hand, during regenerative control during deceleration driving with the shift range in the D range, for example, a "braking force cooperative control" is possible in which the vehicle braking torque TB [Nm], which is the sum of the regenerative torque Tmg and the wheel brake torque Twb, is controlled to become a braking force of a magnitude corresponding to the brake operation amount Bra. That is, the wheel brake torque Twb can be controlled to become a braking force (=vehicle braking torque TB) of a magnitude corresponding to the brake operation amount Bra minus the regenerative torque Tmg. Note that the regenerative torque Tmg is set to a value that does not exceed the torque capacity that the automatic transmission 22 can transmit. Also, the vehicle braking torque TB does not need to be controlled to a magnitude strictly equal to the braking force corresponding to the brake operation amount Bra operated by the driver, but may be controlled to approximately the same magnitude within a range in which the driver does not feel uncomfortable due to a sudden change in the braking force.

[0027] In the vehicle 10, for example, a driving mode (hereinafter referred to as "BEV driving mode") in which the vehicle runs as a Battery Electric Vehicle (BEV) using only the electric motor MG as a power source among the power sources for running, and a driving mode (hereinafter referred to as "engine driving mode") in which the vehicle runs as an engine using at least the engine 12 as a power source among the power sources for running can be selected. In the BEV driving mode, the clutch K0 is in a released state, and in the engine driving mode, the clutch K0 is in an engaged state.

[0028] The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. For example, the electronic control device 90 executes output control of the engine 12, output control of the electric motor MG, connection / disconnection control of the clutch K0, shift control of the automatic transmission 22, etc. The electronic control device 90 corresponds to the "control device" in the present invention.

[0029] The electronic control device 90 receives various signals (e.g., a lever position signal Slev, a P switch signal Spsw, an engine rotation speed which is the rotation speed of the engine 12, an engine speed sensor 72, an output shaft rotation speed sensor 74, an MG rotation speed sensor 76, an accelerator opening sensor 78, a throttle valve opening sensor 80, a brake operation amount sensor 82, a battery sensor 84, etc.) based on detection values ​​from various sensors provided in the vehicle 10. The following are input: Ne [rpm], input shaft rotation speed Nin which is equivalent to turbine rotation speed Nt which is the rotation speed of the turbine impeller, output shaft rotation speed Nout which corresponds to vehicle speed V [km / h], MG rotation speed Nmg which is the rotation speed of the electric motor MG, accelerator opening θacc [%] which represents the amount of accelerator operation by the driver, throttle valve opening θth [%], brake operation amount Bra which represents the amount of deceleration operation by the driver, battery charge / discharge current Ibat [A], battery voltage Vbat [V], battery temperature THbat [℃], etc.

[0030] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, a wheel brake control signal Swb for controlling the wheel brake torque Twb, a shift range indication signal Sindi for indicating the current shift range, a shift control signal Sat for controlling the shifting of the automatic transmission 22, a K0 control signal Sk0 for controlling the engagement and disengagement of the clutch K0, an LU control signal Slu for controlling the engagement and disengagement of the lock-up clutch LU, an MG control signal Smg for controlling the output of the electric motor MG via the inverter 62, etc.) to each device (e.g., the engine 12, the braking oil pressure supply circuit 26b, the indicator 50, the oil pressure control circuit 60, the inverter 62, etc.) provided in the vehicle 10.

[0031] From here, a case will be described in which the shift range is in the D range, the vehicle is in BEV driving, and the shift lever 42 is operated to the short-term N position during regenerative control.

[0032] The electronic control unit 90 functionally comprises a drive device control unit 92 including a power source control unit 92a and a power transmission control unit 92b, a lever operation determination unit 94, a braking force control unit 96 including a wheel brake control unit 96a and a regenerative torque control unit 96b, and a range switching request unit 98.

[0033] The power source control unit 92a controls the output of the engine 12 and the electric motor MG, which are the power sources for traveling. For example, the power source control unit 92a calculates the required driving torque Trdem [Nm] by applying the accelerator opening θacc and the vehicle speed V to a relationship (for example, a driving torque map) that is previously determined experimentally or by design. The power source control unit 92a controls the engine torque Te and the MG torque Tmg so that the required driving torque Trdem is realized, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 22, and the like. During the BEV traveling and regenerative control, the engine 12 is stopped and the engine torque Te is controlled to zero, and the regenerative torque Tmg is controlled to be a braking force of a magnitude corresponding to the brake operation amount Bra. When the regenerative torque Tmg exceeds the torque capacity that the automatic transmission 22 can transmit, the wheel brake torque Twb is controlled to be the excess.

[0034] The power transmission control unit 92b controls the torque output from the power source for driving to be transmitted to the pair of drive wheels 14. The power transmission control unit 92b executes, for example, connection / disconnection control of the clutch K0, connection / disconnection control of the lock-up clutch LU, and shift control of the automatic transmission 22. During BEV driving, the clutch K0 is controlled to be in a released state, and the automatic transmission 22 is controlled to have a predetermined gear ratio γat in the D range.

[0035] The lever operation determination unit 94 determines whether or not the shift lever 42 has been operated to the N position. When the lever operation determination unit 94 determines that the shift lever 42 has been operated to the N position, the lever operation determination unit 94 outputs N operation information indicating the timing at which the shift lever 42 was operated to the N position. The N operation information is output at the start of the operation even if the shift lever 42 is operated to the N position for less than a predetermined holding period Phld [ms] described below. The lever operation determination unit 94 determines whether or not the shift lever 42 operated to the N position has been held for a predetermined holding period Phld or more, that is, whether or not a short-term N operation has been performed. For example, the predetermined holding period Phld is several + [ms] to several hundred [ms].

[0036] When the lever operation determination unit 94 outputs the N operation information, the braking force control unit 96 starts the regenerative torque gradual reduction control. That is, the regenerative torque gradual reduction control is started from the time when the shift lever 42 is operated to the N position. The "regenerative torque gradual reduction control" is a control in which the regenerative torque Tmg is gradually reduced and the wheel brake torque Twb is gradually increased in the braking force cooperative control. That is, in the regenerative torque gradual reduction control, the vehicle braking torque TB is set to a braking force of a magnitude corresponding to the brake operation amount Bra, while the regenerative torque Tmg is gradually reduced and the wheel brake torque Twb is gradually increased. The "regenerative torque gradual reduction control" corresponds to the "braking force cooperative control in which the regenerative torque is gradually reduced and the wheel brake torque is gradually increased" in the present invention.

[0037] When the lever operation determination unit 94 determines that the short-term N operation has been performed, the braking force control unit 96 determines whether a predetermined control period Pctrl [ms] has elapsed since the output of the N operation information, and executes the regenerative torque gradual reduction control for the predetermined control period Pctrl. The "predetermined control period Pctrl" is an execution period of the regenerative torque gradual reduction control that is determined in advance experimentally or by design, during which the driver feels a sense of discomfort due to the shock caused by switching the shift range from the D range to the N range within a predetermined allowable range, and is a period longer than the predetermined holding period Phld. Since the predetermined control period Pctrl is a long period compared to the predetermined holding period Phld, a sufficient period can be set as the execution period of the regenerative torque gradual reduction control. The wheel brake control unit 96a controls the wheel brake device 26 so that the wheel brake torque Twb assigned by the regenerative torque gradual reduction control is obtained. The regenerative torque control unit 96b controls the MG torque Tmg (<0) of the electric motor MG so that the regenerative torque Tmg assigned by the regenerative torque gradual reduction control is obtained.

[0038] When a predetermined control period Pctrl has elapsed, the regenerative torque Tmg becomes equal to or less than a predetermined torque judgment value Tmg_jdg. The predetermined torque judgment value Tmg_jdg is a judgment value of the regenerative torque Tmg at which the shock accompanying the switching of the shift range from the D range to the N range falls within a predetermined allowable range. The smaller the regenerative torque Tmg, the less the twisting of the axles, etc. caused by the regenerative torque Tmg. If the twisting of the axles, etc. is small, a shock is less likely to occur even when the shift range is switched from the D range to the N range and the twisting of the axles, etc. caused by the regenerative torque Tmg is suddenly released. The twisting of the axles, etc. caused by the regenerative torque Tmg is a twisting of the power transmission path PT caused by the regenerative torque Tmg.

[0039] After the regenerative torque gradual reduction control is executed for a predetermined control period Pctrl, the range switching request unit 98 outputs an N switching request signal, which is a control signal requesting to switch the shift range to the N range. When the N switching request signal is output from the range switching request unit 98, the power transmission control unit 92b switches the automatic transmission 22 to the N range. As a result, the shift range becomes the N range in which power transmission to the pair of drive wheels 14 is cut off.

[0040] Note that, when the lever operation determination unit 94 outputs the N operation information but determines that the short-term N operation has not been performed, the braking force control unit 96 stops the started regenerative torque gradual reduction control, and the range switching request unit 98 does not output an N switching request signal. In other words, the shift range is not switched to the N range, and the D range is maintained.

[0041] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control unit 90 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed while the shift range is in the D range and the vehicle is running and regenerative control is being performed.

[0042] First, in step S10 (hereinafter, "step" will be omitted), which corresponds to the function of the lever operation determination unit 94, it is determined whether or not the shift lever 42 has been operated to the N position. If the determination in S10 is YES, N operation information is output in S20, which corresponds to the function of the lever operation determination unit 94. After execution of S20, in S30, which corresponds to the function of the braking force control unit 96, regenerative torque gradual reduction control is started.

[0043] After the execution of S30, in step S40 corresponding to the function of the lever operation determination unit 94, it is determined whether or not a short-term N operation has been performed. If the determination of S40 is YES, in S50 corresponding to the function of the braking force control unit 96, it is determined whether or not a predetermined control period Pctrl has elapsed since the output of the N operation information. If the determination of S50 is NO, S50 is executed again. If the determination of S50 is YES, in S60 corresponding to the function of the range switching request unit 98, an N switching request signal is output. After the execution of S60, in S70 corresponding to the function of the power transmission control unit 92b, the automatic transmission 22 is switched to the N range, so that the shift range is switched to the N range. If the determination of S40 is NO, in S80 corresponding to the function of the braking force control unit 96, the regenerative torque gradual reduction control started in S30 is stopped. If the determination of S10 is NO, after the execution of S70 and after the execution of SS80, both are returned.

[0044] Fig. 3 is an example of a time chart when the flowchart of Fig. 2 is executed. In Fig. 3, the horizontal axis represents time t [ms].

[0045] Before time t1, the vehicle 10 is traveling with the shift range in the D range and is under regenerative control. For example, the accelerator opening θacc is zero, the brake operation amount Bra is a constant value (>0), and the state of the automatic transmission 22 is the D range. As a result, the regenerative torque Tmg is controlled to a predetermined torque value Tmg1, and the wheel brake torque Twb is controlled to a predetermined torque value Twb1.

[0046] At time t1, the driver operates the shift lever 42 from the "H position" to the "N position". At time t3 (>t1), the driver releases the shift lever 42, and the shift lever 42 returns to the "H position". That is, during the period from time t1 to time t3, the shift lever 42 is held at the "N position", and the lever position signal Slev is a signal representing the "N position". The period from time t1 to time t3 is longer than a predetermined holding period Phld. The switching delay signal for delaying the switching timing of the shift range switches from the off state to the on state at time t1, and switches from the on state to the off state at time t5 (=t1 + Pctrl) which is delayed by a predetermined control period Pctrl from time t1.

[0047] Due to the shift lever 42 being operated to the "N position" at time t1, the regenerative torque gradual reduction control is started, and the regenerative torque Tmg is gradually reduced from a predetermined torque value Tmg1, and the wheel brake torque Twb is gradually increased from a predetermined torque value Twb1. Time t2 is the time when a predetermined holding period Phld has elapsed from time t1. During the period from time t2 (=t1 + Phld) to time t3, a short-term N operation determination signal indicating that the shift lever 42 has been held at the "N position" for a predetermined holding period Phld or more is set to the on state. When the short-term N operation determination signal is set to the on state, the regenerative torque gradual reduction control is executed until time t5. For example, at time t4 (<t5) before time t5, the regenerative torque Tmg becomes a zero value that is equal to or less than a predetermined torque determination value Tmg_jdg, and the wheel brake torque Twb becomes the sum of a predetermined torque value Twb1 and a predetermined torque value Tmg1 (=Twb1 + Tmg1 <0).

[0048] At time t5 when the switching delay signal switches from the on state to the off state, an N switching request signal is output, whereby a shift range control signal that controls the shift range (for example, a shift control signal Sat that controls the automatic transmission 22 to a neutral state) is switched from the D range to the N range, and the transmission state signal is switched from the D range to the N range. The transmission state signal is a signal that indicates the power transmission state in the automatic transmission 22. When the transmission state signal is in the D range, the automatic transmission 22 is in a state that allows the vehicle 10 to travel forward. When the transmission state signal is in the N range, the automatic transmission 22 is in a neutral state in which the power transmission of the vehicle 10 is cut off. When the transmission state signal is switched from the D range to the N range, the automatic transmission 22 is placed in a neutral state.

[0049] According to this embodiment, when the shift lever 42 is held in the N position for a predetermined holding period Phld or more during regenerative control while the shift range is in the D range, the regenerative torque gradual reduction control is executed for the predetermined control period Pctrl, and then the shift range is switched to the N range. In this way, the regenerative torque Tmg is gradually reduced by the regenerative torque gradual reduction control executed for the predetermined control period Pctrl. After the predetermined control period Pctrl has elapsed, the twisting of the power transmission path PT caused by the regenerative torque Tmg has been sufficiently reduced, so that the occurrence of shock is suppressed even when the shift range is switched to the N range. Therefore, even if the shift lever is operated to the N position for a short period of time, the shift range is switched to the N range while suppressing the occurrence of shock.

[0050] According to this embodiment, the regenerative torque reduction control is started from the time when the shift lever 42 is operated to the N position. In this way, since the regenerative torque reduction control is started before it is determined that the short-term N operation has been performed, it is possible to shorten the predetermined control period Pctrl by the predetermined holding period Phld. This suppresses delays in switching the shift range to the N range during the short-term N operation.

[0051] According to this embodiment, if the shift lever 42 is operated to the N position but is not held at the N position for a predetermined holding period Phld or more, the regenerative torque reduction control that started from the time the shift lever 42 was operated to the N position is stopped. The predetermined holding period Phld is a period shorter than the predetermined control period Pctrl. If the shift lever 42 is not held at the N position for the predetermined holding period Phld or more, the regenerative torque reduction control is only executed for the short period of the predetermined holding period Phld. As a result, after the regenerative torque reduction control is stopped, regenerative control in which the regenerative torque Tmg is greater than the wheel brake torque Twb is easily executed.

[0052] According to this embodiment, the predetermined control period Pctrl is a fixed period that is set in advance so that the shock caused by switching the shift range from D range to N range falls within a predetermined allowable range. By setting the predetermined control period Pctrl to a fixed period, the regenerative torque Tmg is reliably reduced, and the complexity of the control is suppressed, as compared to a mode in which the predetermined control period Pctrl is changed depending on the magnitude of the regenerative torque Tmg immediately before the short-term N operation is performed, for example.

[0053] It should be noted that the above is an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0054] In the above embodiment, the shift range is the D range, and the short-term N operation of the shift lever 42 is performed during regenerative control while the vehicle is in the BEV mode. However, the present invention is also applicable to a case where the shift range is the R range instead of the D range. In this case, the R range corresponds to the "driving range" in the present invention.

[0055] In the above embodiment, the regenerative torque gradual reduction control is started from the time when the shift lever 42 is operated to the N position, but the present invention is not limited to this. For example, the regenerative torque gradual reduction control may be started from the time when it is determined that a short-term N operation has been performed. In addition, in the above embodiment, the regenerative torque gradual reduction control is stopped in S80 of the flowchart in FIG. 2, but the present invention is not limited to this. For example, the regenerative torque gradual reduction control may be continued without being stopped, or a braking force cooperative control that gradually increases the regenerative torque Tmg and gradually reduces the wheel brake torque Twb may be executed, and the regenerative torque Tmg and the wheel brake torque Twb may be returned to the state at the start of execution of S30.

[0056] In the above embodiment, the predetermined control period Pctrl is a predetermined fixed period during which the shock accompanying the shift range switching from the D range to the N range falls within a predetermined allowable range, but the present invention is not limited to this. For example, the predetermined control period Pctrl may be a period during which the regenerative torque Tmg is equal to or less than a predetermined torque determination value Tmg_jdg, during which the shock accompanying the shift range switching from the D range to the N range falls within a predetermined allowable range (see FIG. 3). In this case, the regenerative torque gradual reduction control is executed during the period during which the regenerative torque Tmg is equal to or less than the predetermined torque determination value Tmg_jdg. This makes the regenerative torque gradual reduction control a necessary and sufficient period, thereby suppressing the occurrence of shock and suppressing excessive delay in switching to the N range.

[0057] In the above-described embodiment, the brake operation amount Bra is a constant value (>0) in the time chart of FIG. 3, but the present invention is not limited to this. For example, the present invention is also applicable to an aspect in which the brake operation amount Bra is zero. Furthermore, the present invention is also applicable to an aspect in which the brake operation amount Bra changes. In the aspect in which the brake operation amount Bra changes, the regenerative torque gradual reduction control gradually reduces the regenerative torque Tmg and gradually increases the wheel brake torque Twb while setting the vehicle braking torque TB to a braking force of a magnitude corresponding to the changing brake operation amount Bra.

[0058] In the above embodiment, the shift lever 42 is operated to the short-term N position during regeneration control while the shift range is in the D range and the vehicle is traveling in the BEV mode. However, the present invention is not limited to this embodiment. For example, the present invention is also applicable to a case where the shift lever 42 is operated to the short-term N position during regeneration control while the shift range is in the D range and the vehicle is traveling in the engine mode. In this embodiment, when the shift lever 42 is operated to the short-term N position, the engine torque Te, which is an engine brake, the regeneration torque Tmg, and the wheel brake torque Twb act as braking forces, and the automatic transmission 22 is switched from the D range to the N range after the regeneration torque gradual reduction control (i.e., the braking force cooperative control that gradually reduces the regeneration torque Tmg and gradually increases the wheel brake torque Twb) is performed for a predetermined control period Pctrl.

[0059] In the above embodiment, the shift range is switched to the N range by setting the automatic transmission 22 to the N range, but the present invention is not limited to this. For example, if the vehicle 10 is provided with a starting clutch instead of the torque converter 20 in the vehicle configuration of the above embodiment, the shift range may be switched to the N range by setting the starting clutch to a released state (=disconnected state) to interrupt the power transmission path PT and set the shift range to the N range. For example, if the vehicle 10 is provided with the engine 12 and the clutch K0 in the vehicle configuration of the above embodiment, the shift range may be switched to the N range by setting the electric motor MG to a non-driven state (=idling state). [Explanation of symbols]

[0060] 10: vehicle, 42: shift lever (operator), 90: electronic control device (control device), Bra: brake operation amount, Pctrl: predetermined control period (predetermined second period), Phld: predetermined holding period (predetermined first period), TB: vehicle braking torque, Tmg: MG torque (regenerative torque), Tmg_jdg: predetermined torque judgment value, Twb: wheel brake torque

Claims

1. A control device for a vehicle having an automatic return type operator operated to switch a shift range, When the shift range is in a drive range and the vehicle is traveling and regenerative control is being performed, if the operator is held at an N position for selecting the N range for a predetermined first period or more, a braking force cooperative control is performed for a predetermined second period in which the regenerative torque is gradually decreased and the wheel brake torque is gradually increased, and then the shift range is switched to the N range. A vehicle control device comprising:

2. The braking force cooperative control is started from the time when the operating member is operated to the N position.

2. The vehicle control device according to claim 1.

3. When the operating element is not held at the N position for the first period or longer, the braking force cooperative control that was started from the time when the operating element was operated to the N position is stopped.

3. The vehicle control device according to claim 2.

4. The second predetermined period is a predetermined fixed period during which a shock caused by switching the shift range from the driving range to the N range falls within a predetermined allowable range.

4. The vehicle control device according to claim 1,

5. The second predetermined period is a period during which a shock caused by switching the shift range from the drive range to the N range falls within a predetermined allowable range and the regenerative torque falls below a predetermined torque judgment value.

4. The vehicle control device according to claim 1,

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