Vehicle control device

Abstract

This vehicle control device controls the traveling of a vehicle by switching the respective connection and disconnection states of a first power transmission path between an engine and a drive shaft and a second power transmission path between a rotary electric machine and the drive shaft, the vehicle control device limiting a deceleration torque due to a regenerative brake so that the deceleration torque is greater than a lower limit torque in accordance with a brake operation amount on the vehicle exceeding a prescribed threshold, when the first power transmission path is in an engaged state and the second power transmission path is in a released state.

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Hybrid vehicles equipped with an engine and a rotating electric machine (motor, generator, motor generator) have become popular. Hybrid vehicles have multiple driving modes that can be switched based on user operation, etc. Driving modes include an EV mode in which the vehicle runs solely on the motor using battery charging power, a series mode in which the vehicle runs solely on the motor while the engine generates electricity for the generator, and a parallel mode in which the vehicle runs primarily on the engine with assistance from the motor when necessary.

[0003] In addition, some hybrid vehicles are equipped with regenerative braking systems. In these vehicles, in order to recover deceleration energy during braking, the motor or generator generates power as regenerative torque to the extent possible, depending on the amount of braking.

[0004] In hybrid vehicles that can output engine power and motor power separately, separate power transmission paths are provided: one from the engine to the drive wheels, and the other from the motor to the drive wheels. Each power transmission path is provided with a clutch, and the transmission of power is controlled by engaging or disengaging the clutch. Furthermore, if the vehicle can maintain running using only engine output while the engine clutch is engaged, disengaging the motor clutch can reduce drag loss and other issues. When the motor clutch is disengaged, unnecessary power consumption can be reduced by setting the motor rotation speed to zero or nearly zero.

[0005] Various controls have been studied for events that occur when the clutch is engaged / disengaged, with the aim of improving the driver's operational feel, etc. Patent Document 1 discloses a configuration that compensates for the response delay between when the accelerator pedal is depressed and when the clutch is engaged, with the aim of improving the response delay when the clutch is engaged. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 148973 Summary of the Invention [Problem to be solved by the invention]

[0007] When the motor clutch is engaged, the motor rotation speed is synchronized with the axle rotation to suppress clutch engagement shocks and the like. This requires a rotation synchronization time and a clutch engagement time for the clutch engagement operation. If the vehicle is suddenly decelerated while the motor clutch is disengaged, the vehicle speed drops to a range where engine stall may occur before the motor rotation synchronization and the motor clutch engagement operation occur. To avoid engine stall, the engine clutch must be reliably disengaged below a certain vehicle speed. At this time, the engine and motor, which can transmit power to the axle, are no longer connected, and the driving force becomes zero. Subsequently, when the motor clutch is engaged, the deceleration torque returns, causing vehicle vibration due to fluctuations in driving force.

[0008] The present invention has been devised in view of the above-mentioned problems, and aims to suppress vehicle vibrations that occur due to control when sudden deceleration occurs while the motor clutch is in an open state. However, this is not the only aim of the present invention. Another aim of the present invention is to achieve effects that cannot be obtained by conventional techniques, which are derived from the configurations shown in the below-described embodiments of the invention. [Means for solving the problem]

[0009] A vehicle control device according to one embodiment of the present invention has the following configuration: The vehicle control device controls vehicle travel by switching between an engaged state and a disconnected state of a first power transmission path between an engine and a drive shaft and a second power transmission path between a rotating electric machine and the drive shaft, and when the first power transmission path is engaged and the second power transmission path is disengaged, limits the deceleration torque generated by regenerative braking to be greater than a lower limit torque in response to an amount of braking operation for the vehicle exceeding a predetermined threshold. [Effects of the Invention]

[0010] According to the present invention, it is possible to suppress vehicle vibrations that occur due to control when sudden deceleration occurs while the motor clutch is in the disengaged state. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a vehicle according to an embodiment of the present invention; [Figure 2] FIG. 4 is a graph illustrating control timing according to the embodiment. [Figure 3] 5 is a graph illustrating the relationship between a suppression gain and a brake operation amount according to a shift range according to the embodiment. FIG. [Figure 4] FIG. 4 is a graph illustrating a suppression gain according to a brake operation according to the embodiment. [Figure 5] 3 is a flowchart of control according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A vehicle control device according to an embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and are not intended to exclude various modifications or applications of techniques not explicitly described in the following embodiments. The configurations of the present embodiment can be modified in various ways without departing from the spirit of the invention. Furthermore, they can be selected or combined as needed. In addition, the same reference numerals are used to indicate corresponding relationships between the same components in the drawings.

[0013] First Embodiment [Overall configuration] A vehicle 100 to which the control device according to this embodiment can be applied will be described. The vehicle 100 is a hybrid vehicle equipped with an engine 101 as a drive source, a motor 107 (first rotating electric machine) for driving, and a generator 102 for generating electricity. Therefore, the vehicle 100 according to this embodiment can be a so-called HV (Hybrid Vehicle), HEV (Hybrid Electric Vehicle), or PHEV (Plug-in Hybrid Electric Vehicle: a plug-in hybrid capable of external charging or external power supply). In this embodiment, the vehicle 100 will be described as a front-wheel drive vehicle, but is not limited to this.

[0014] The generator 102 is connected to the engine 101 and can operate independently of the operation of the motor 107. The engine 101 is connected to a drive shaft 104 via an engine clutch 103. When the engine clutch 103 is engaged, power generated by the engine 101 is transmitted to the drive shaft 104. The motor 107 is connected to the drive shaft 104 via a motor clutch 106. When the motor clutch 106 is engaged, power generated by the motor 107 is transmitted to the drive shaft 104. For convenience, the power transmission path via the engine clutch 103 is also referred to as a "first power transmission path," and the power transmission path via the motor clutch 106 is also referred to as a "second power transmission path."

[0015] Driving wheels 105 (front wheels) are mounted on the driving shaft 104. Driven wheels 114 (rear wheels) are mounted on the axle 113.

[0016] The vehicle 100 is also provided with an ECU (Electronic Control Unit) 108, which corresponds to the control device according to this embodiment. The ECU 108 is an electronic control device configured as, for example, an LSI (Large-Scale Integration) device or an embedded electronic device that integrates a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The ECU 108 acquires signals detected by various sensors provided in the vehicle 100 via a CAN (Car Area Network) or the like, and controls the vehicle 100. The sensors provided in the vehicle 100 include an accelerator position sensor 109, a brake sensor 110, and a speed sensor 111. The accelerator position sensor 109 detects the amount of depression (accelerator position) of an accelerator pedal (not shown). The brake sensor 110 detects the amount of depression of a brake pedal (not shown). The speed sensor 111 detects the vehicle speed of the vehicle 100. The vehicle 100 is also provided with a driving battery 112, which is supplied with power and is charged.

[0017] The engine 101 is an internal combustion engine (gasoline engine or diesel engine) that uses gasoline or diesel as fuel. The operating state of the engine 101 may be controlled by the ECU 108, or may be controlled by an electronic control device (not shown) separate from the ECU 108. The generator 102 and motor 107 according to this embodiment are motor generators (motor-generators) that function as both an electric motor and a generator. The motor 107 is a drive source that exchanges electric power with the battery 112, and functions mainly as an electric motor to drive the vehicle 100 and as a generator during regeneration.

[0018] The generator 102 functions as an electric motor (starter) when starting the engine 101, and is driven by the power of the engine 101 to generate electricity when the engine 101 is operating. Furthermore, the generator 102 transmits driving force to the drive shaft 104 of the vehicle 100 in a powered state. An inverter (not shown) that converts DC current to AC current is provided around (or inside) each of the motor 107 and the generator 102. The rotation speeds and operating states (powered operation, regenerative / powered operation) of the motor 107 and the generator 102 are controlled by controlling the inverter (not shown).

[0019] The vehicle 100 can run in a plurality of driving modes, such as EV mode, series mode, and parallel mode. These driving modes are selected by the ECU 108 in accordance with the vehicle state, driving state, the driving force required by the driver, etc. Furthermore, the operations of the engine 101, generator 102, and motor 107 are selectively controlled depending on the driving mode.

[0020] The EV mode is a driving mode in which the vehicle 100 is driven solely by the motor 107 using the power stored in the drive battery 112, while the engine 101 and the generator 102 are stopped. The EV mode is selected, for example, when the required driving force and vehicle speed are both low or when the charge level of the battery 112 is high. The series mode is a driving mode in which the engine 101 drives the generator 102 to generate electricity, and the generated electricity is used to drive the vehicle 100 by the motor 107. The series mode is selected, for example, when the required driving force is high or the charge level of the battery 112 is low. The parallel mode is a driving mode in which the vehicle 100 is driven primarily by the driving force of the engine 101, and the motor 107 assists in driving the vehicle 100 as needed. The parallel mode is selected, for example, when the vehicle speed is high or the required driving force is high. Note that the switching control and application situations for each driving mode are not limited to those described above, and the switching may be performed according to any conditions.

[0021] An engine 101 and a motor 107 are connected in parallel to drive wheels 105 (front wheels in this case) via a transaxle (not shown) incorporating multiple gears and clutches. The engine 101 is also connected to a generator 102 via a transaxle (not shown), and the power of the engine 101 is also transmitted to the generator 102.

[0022] A transaxle is a power transmission device that integrates a final drive (final reduction gear) including a differential and a transmission (reduction gear), and contains multiple mechanisms that transmit power between the driving source and the driven device.

[0023] The engine clutch 103 is, for example, a wet multi-plate clutch or a dog clutch. Power on the upstream side of the power transmission path (the engine 101 and generator 102 side) of the engine clutch 103 is transmitted to the drive shaft 104 when the engine clutch 103 is in an engaged state (connected state), and is cut off when the engine clutch 103 is in a released state (disconnected state). The engaged / disconnected state of the engine clutch 103 is controlled by the ECU 108.

[0024] The motor clutch 106 is, for example, a wet multi-plate clutch or a dog clutch. Power on the upstream side of the power transmission path from the motor clutch 106 (i.e., the driving force of the motor 107) is transmitted to the drive shaft 104 when the motor clutch 106 is engaged, and is cut off when the motor clutch 106 is disengaged. The engaged / disengaged state of the motor clutch 106 is controlled by the ECU 108.

[0025] For example, when the driving mode is EV mode or series mode, the engine clutch 103 is released and the motor clutch 106 is engaged. When the driving mode is parallel mode and motor assist (driving force of the motor 107) is not required, the engine clutch 103 is engaged and the motor clutch 106 is released. When the driving mode is parallel mode and motor assist is required, both the engine clutch 103 and the motor clutch 106 are engaged.

[0026] The vehicle 100 according to this embodiment is equipped with a regenerative braking function. The strength of the regenerative braking force produced by the regenerative brake can be adjusted by switching the shift range based on the driver's operation, etc. The number of shift range stages for setting the regenerative braking force is not particularly limited, but three stages, B0, B1, and B2, will be used as an example for explanation here. The symbols indicating the shift ranges are merely examples and do not necessarily correspond to the symbols of the shift ranges actually installed in the vehicle 100. The relationship between the strength of the regenerative braking force is B2>B1>B0.

[0027] [Control timing] FIG. 2 is a diagram illustrating the control timing of the vehicle 100 according to this embodiment. FIG. 2(a) is a graph showing changes in the amount of brake operation, with the vertical axis showing the amount of brake operation and the horizontal axis showing time. FIG. 2(b) is a graph showing changes in the vehicle speed of the vehicle 100, with the vertical axis showing vehicle speed and the horizontal axis showing time. FIG. 2(c) is a graph showing the engagement / disengagement state of the motor clutch 106, with the vertical axis showing either a released state (open) or an engaged state (closed), and the horizontal axis showing time. FIG. 2(d) is a graph showing the engagement / disengagement state of the engine clutch 103, with the vertical axis showing either a released state (open) or an engaged state (closed), and the horizontal axis showing time. FIG. 2(e) is a graph showing changes in drive torque, with the vertical axis showing drive torque and the horizontal axis showing time. It is assumed that the timings of the graphs shown in FIG. 2 are consistent.

[0028] The following explanation will be made while associating each graph. Here, the explanation will be made taking as examples a driving mode in which the vehicle runs using power from the engine 101 (hereinafter also referred to as "first driving mode") and a driving mode in which the vehicle runs using power from the motor 107 (hereinafter also referred to as "second driving mode"). Also, at the left end of the graph shown in FIG. 2 (time t0), the vehicle 100 is assumed to be running at a constant vehicle speed in the first driving mode. Therefore, the motor clutch 106 is in a released state, and the engine clutch 103 is in an engaged state.

[0029] First, conventional operation and control will be described. Graph 214 in Figure 2(e) corresponds to the conventional change. At time t0, the driving torque has a constant value (i.e., deceleration torque) on the regenerative side. Although not shown in Figure 2, it is assumed that there is no operation on the accelerator pedal at time t0. Therefore, the driving torque at time t0 corresponds to the engine braking torque.

[0030] At time t1, the driver starts braking. Here, it is assumed that the amount of braking increases at a constant rate until time t5, and then remains constant. As the braking operation starts, the vehicle speed of vehicle 100 starts to decrease, and the value of the driving torque to the regeneration side (i.e., deceleration torque) increases.

[0031] After that, the drive torque value becomes constant after reaching a predetermined value. Then, when the vehicle speed falls below a certain value (time t5), the engine clutch 103 is released to prevent the engine from stalling. At this time, the motor clutch 106 is also released, so power supply to the drive shaft 104 becomes zero (times t5 to t6). After that, when the motor clutch 106 is engaged (time t6), power is supplied to the drive shaft 104, but the sudden drive torque causes vibration of the vehicle 100 (the range of dashed line 210 in FIG. 2(e)). Note that the engagement operation of the motor clutch 106 may be started before the engine clutch 103 is released, but this engagement operation takes a certain amount of time, so there may be a period of time during which power to the drive shaft 104 becomes zero.

[0032] The fluctuations in the driving torque during the time periods from time t4 to t5 and from time t6 to t7 are caused by the processes accompanying the engagement / disengagement of each clutch.

[0033] In the above control, from time t0 to time t5, the power of the engine 101 and the generator 102 is supplied to the drive shaft 104. Furthermore, from time t6 to time t7, the power of the motor 107 is supplied to the drive shaft 104.

[0034] Next, the operation and control according to this embodiment will be described. The operation shown in Figures 2(a) to 2(d) is assumed to be the same. Graph 212 in Figure 2(e) corresponds to the change in this embodiment. Graphs 211 and 213 show the lower limit value (lower limit torque) for the drive torque according to this embodiment, and the lower limit value is switched depending on the shift range. Control based on the shift range will be described later.

[0035] At time t0, the driving torque has a constant value (i.e., deceleration torque) on the regeneration side, which is the same value as that in the conventional control shown in graph 211.

[0036] At time t1, the driver starts braking. Here, it is assumed that the amount of braking increases at a constant rate until time t5, and then remains constant. As the braking starts, the speed of vehicle 100 starts to decrease, and the value of the driving torque to the regeneration side (i.e., deceleration torque) increases.

[0037] After that, the value of the driving torque reaches a predetermined value and then becomes constant. Then, at the timing shown as time t3, it is assumed that the brake operation amount reaches the threshold value (threshold value 202 in FIG. 2(a)).

[0038] When the brake operation amount reaches the threshold, the drive torque is controlled to approach 0. In other words, the drive torque is suppressed in accordance with the change in the lower limit torque shown in graph 211. The amount of change in the drive torque here will be described in detail later. Thereafter, control is performed so that the drive torque remains constant (0 in this case). As a result, fluctuations within the range of dashed line 210 are suppressed, making it possible to suppress vibrations that would previously have occurred.

[0039] Graph 213 shows a change in the lower limit range corresponding to a different shift range from that of graph 211. In this case, the threshold value for the brake operation amount is set to threshold value 201 in FIG. 2(a). In other words, threshold value 201 is set to a value lower than threshold value 202 as the threshold value for the brake operation amount. The change in the lower limit torque begins at time t2 when the brake operation amount reaches threshold value 201. The threshold value for the brake operation amount may be set in accordance with the shift range described above.

[0040] Fig. 3 is a graph showing the relationship between the brake operation amount and the suppression gain relative to the drive torque according to this embodiment. In Fig. 3, the vertical axis represents the suppression gain (0 to 1), and the horizontal axis represents the brake operation amount. In this embodiment, the relationship between the brake operation amount and the suppression gain is switched depending on the shift range described above. The higher the suppression gain, the stronger the braking force based on the brake operation amount.

[0041] In this embodiment, the suppression gain is defined so that the higher the regenerative braking force in the shift range, the faster the reduction in the suppression gain relative to the amount of brake operation. That is, in shift range B2, which has the highest regenerative braking force among the shift ranges exemplified above, the suppression gain decreases most quickly in response to an increase in the amount of brake operation. On the other hand, in shift range B0, which has the lowest regenerative braking force, the suppression gain decreases most slowly in response to an increase in the amount of brake operation. Information indicating this correspondence is set in advance in a database or the like, and ECU 108 reads it out as appropriate depending on the shift range to perform control.

[0042] FIG. 4 is a diagram illustrating the relationship between the brake operation amount, brake operation determination, and suppression gain over time. FIG. 4(a) is a graph showing changes in the brake operation amount, with the vertical axis representing the brake operation amount and the horizontal axis representing time. FIG. 4(b) is a graph showing the on / off determination result of the brake operation determination, with the vertical axis representing either the on state or the off state of the brake operation and the horizontal axis representing time. FIG. 4(c) is a graph showing changes in the suppression gain, with the vertical axis representing the value of the suppression gain and the horizontal axis representing time. It is assumed that the time timing is consistent in each graph shown in FIG. 4.

[0043] 4A, threshold values ​​Tha, Thb, and Thc for the brake operation amount indicate threshold values ​​corresponding to the shift ranges B2, B1, and B0 exemplified above, respectively. That is, the threshold value Tha corresponding to B2 is set to the lowest value.

[0044] In the case of shift range B2, the brake operation determination is turned ON at time t1 when the brake operation amount reaches Tha. Accordingly, the suppression gain decreases. In the case of shift range B1, the brake operation determination is turned ON at time t2 when the brake operation amount reaches Thb. Accordingly, the suppression gain decreases. In the case of shift range B2, the brake operation determination is turned ON at time t3 when the brake operation amount reaches Thc. Accordingly, the suppression gain decreases.

[0045] 3 and 4, the suppression gain is reduced at a constant reduction rate (constant proportionality) regardless of the shift range, but this is not limiting. For example, the suppression gain may be reduced at a rate of change indicated by a curve. Furthermore, the rate of change may differ depending on the shift range.

[0046] In this embodiment, the lower limit torque (graphs 211 and 213) shown in FIG. 3 is derived by the following equation (1). (Lower limit torque) = (fixed value) × (suppression gain) (1) In this case, the fixed value may be a value corresponding to a predetermined minimum driving torque.

[0047] [Control Flow] 5 is a flowchart of the control process according to this embodiment. This process flow may be implemented by the ECU 108 reading and executing the program and various data according to this embodiment. In this case, the ECU 108 performs control in cooperation with various parts of the vehicle 100 by transmitting and receiving data to and from these parts. When this process is performed, it is assumed that the vehicle 100 is in a state where it can run and is running in one of the running modes described above.

[0048] In step S501, ECU 108 determines whether the current driving mode of vehicle 100 is the first driving mode. If it is the first driving mode (YES in step S501), the process of ECU 108 proceeds to step S502. On the other hand, if it is not the first driving mode (NO in step S501), this process flow ends. In this case, vehicle 100 continues to travel in a mode other than the first driving mode.

[0049] In step S502, the ECU 108 sets a start threshold based on the shift range. This corresponds to the thresholds 201 and 202 for the brake operation amount shown in Fig. 4(a). The start threshold may be determined in advance according to the shift range, and the ECU 108 reads it from a storage unit (not shown) and sets it.

[0050] In step S503, the ECU 108 acquires detection values ​​from various sensors. In this embodiment, the acquired detection values ​​may include the vehicle speed, the amount of braking operation, and the like.

[0051] In step S504, ECU 108 determines whether the brake operation amount has reached the start threshold set in step S502, based on the detection value acquired in step S503. If the brake operation amount has reached the start threshold (YES in step S504), the process by ECU 108 proceeds to step S505. On the other hand, if the brake operation amount has not reached the start threshold (NO in step S504), the process by ECU 108 returns to step S503, and the process is repeated.

[0052] In step S505, ECU 108 derives the suppression gain based on the detection value acquired in step S505 and the shift range. As described with reference to Fig. 3, a look-up table (LUT) or the like that associates the brake operation amount with the shift range is predefined and stored in the storage unit, and ECU 108 derives the suppression gain by referring to this. Note that the method for deriving the suppression gain is not limited to the table format, and it may be derived using a predefined calculation formula.

[0053] In step S506, ECU 108 starts suppressing the drive torque by the lower limit torque derived based on the suppression gain derived in step S506. Note that when the drive torque is greater than the lower limit torque, such as from time t2 to time t3 in FIG. 2(e), the drive torque is not limited.

[0054] In step S507, ECU 108 determines whether the vehicle speed has become equal to or less than a predetermined threshold. At this time, ECU 108 may acquire a detected value of the vehicle speed from speed sensor 111. The threshold here is a threshold used to determine whether to disengage engine clutch 103, and corresponds to the threshold used for the determination at time t5 in FIG. 2. If the vehicle speed has become equal to or less than the threshold (YES in step S507), the processing of ECU 108 proceeds to step S508. On the other hand, if the vehicle speed is greater than the threshold (NO in step S507), the processing of ECU 108 returns to step S503, and the processing is repeated.

[0055] In step S508, the ECU 108 starts the engagement operation of the motor clutch 106. This engagement operation includes an operation for synchronizing the motor rotation speed with the rotation of the axle, and it takes a certain amount of time to achieve this synchronization. It is preferable that the engagement operation of the motor clutch 106 starts before the engine clutch 103 is released. Furthermore, the time required for the engagement operation can be specified in advance, and the timing for starting the engagement operation may be controlled depending on that time.

[0056] In step S509, ECU 108 releases engine clutch 103. This prevents engine stall due to a decrease in speed. As described with reference to FIG. 2, the drive torque is already controlled to a constant value (approximately zero in the example of FIG. 2(e)) at the timing when engine clutch 103 is released.

[0057] In step S510, the ECU 108 engages the motor clutch 106. This is because the operation started in step S508 has successfully performed rotation synchronization and the like, thereby engaging the motor clutch 106.

[0058] In step S511, the ECU 108 switches to the second driving mode and continues driving the vehicle 100. That is, the vehicle 100 continues driving by the power of the motor 107. Then, this processing flow ends.

[0059] As described above, this embodiment makes it possible to suppress vehicle vibrations that occur due to control when sudden deceleration occurs while the motor clutch is in an open state. It is also possible to suppress vehicle vibrations that occur due to control. Furthermore, by switching the control timing according to the shift range corresponding to the regenerative braking force, it becomes possible to perform more appropriate vibration suppression control according to the state of the vehicle.

[0060] <Other embodiments> In the above embodiment, the brake operation has been described assuming an operation by a driver. However, this is not limiting, and the configuration of the present invention may be applied when an ECU or the like performs a brake operation in a driving assistance function or an autonomous driving function such as an ADAS (Advanced Driver-Assistance Systems) or an ADS (Autonomous Driving System). Therefore, the above brake operation amount may be applied by being read as a brake control amount by the system side.

[0061] In the above embodiment, the timing for limiting the deceleration torque is controlled based on the brake operation amount. However, the present invention is not limited to this. The timing for limiting the deceleration torque may be controlled based on the vehicle deceleration instead of the brake operation amount. In this configuration, the deceleration torque may be limited by the lower limit torque when the deceleration is equal to or greater than a predetermined threshold. The threshold used in this configuration may differ depending on the shift range. Alternatively, the deceleration torque may be limited by the lower limit torque based on both the brake operation amount and the deceleration, or the limit may be switched between the brake operation amount and the deceleration depending on the vehicle driving mode.

[0062] In the above embodiment, a configuration has been shown in which the drive torque due to the regenerative brake is suppressed. Here, if a situation in which the braking force is insufficient is expected, a configuration may be adopted in which the braking force is supplemented using a hydraulic brake (not shown) provided in the vehicle 100. In other words, control may be performed to use the hydraulic brake in combination in the period from time t3 to time t8 in FIG. 2. This makes it possible to suppress a situation in which insufficient deceleration occurs due to insufficient braking force.

[0063] Furthermore, in the above embodiment, an example was shown in which the threshold value for initiating a brake operation (corresponding to threshold values ​​201 and 202 in FIG. 2) was switched in association with the shift range, but the present invention is not limited to this. For example, a configuration may be adopted in which the threshold value for initiating a brake operation is switched based on the condition (e.g., slope) of the road surface on which the vehicle 100 is traveling. The condition of the road surface may be identified based on map information, vehicle position information, information obtained by an environmental sensor provided in the vehicle 100, or the like.

[0064] The above-described control may be configured to release the limit on the drive torque imposed by the lower limit torque when the accelerator pedal is operated.

[0065] The above-described control may be configured to re-derive the value of the lower limit torque due to switching of the shift range.

[0066] In addition, in the present invention, a program or application for realizing the functions of one or more of the above-mentioned embodiments can be supplied to a system or device using a network or a storage medium, etc., and one or more processors in the computer of the system or device can read and execute the program.

[0067] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0068] As described above, the present specification discloses the following: (1) A vehicle control device that controls vehicle running by switching between connection and disconnection states of a first power transmission path between an engine and a drive shaft and a second power transmission path between a rotating electric machine and the drive shaft, When the first power transmission path is in an engaged state and the second power transmission path is in a disengaged state, in response to a brake operation amount for the vehicle exceeding a predetermined threshold, a deceleration torque by a regenerative brake is limited to be greater than a lower limit torque. Vehicle control device. This configuration makes it possible to suppress vehicle vibrations that occur due to control when sudden deceleration occurs while the motor clutch is in the disengaged state.

[0069] (2) The lower limit torque is derived using a fixed value and a suppression gain, The suppression gain varies depending on a brake operation amount for the vehicle. A control device for a vehicle as described in (1). According to this configuration, it is possible to set a lower limit torque for limiting the deceleration torque in accordance with the amount of brake operation.

[0070] (3) The vehicle control device according to (2), wherein the suppression gain is set to a different value according to a plurality of shift ranges that have different regenerative braking forces. According to this configuration, it is possible to set a lower limit torque for limiting the deceleration torque in accordance with the shift ranges that have different regenerative braking forces.

[0071] (4) The vehicle control device according to (1), wherein the predetermined threshold value is set to a different value according to a plurality of shift ranges that have different regenerative braking forces. According to this configuration, it is possible to adjust the timing for limiting the deceleration torque in accordance with the shift ranges that have different regenerative braking forces.

[0072] (5) The vehicle control device according to (4), wherein the predetermined threshold value is set to a lower value as the regenerative braking force of the shift range increases among the plurality of shift ranges. According to this configuration, it is possible to adjust the timing so that the deceleration torque is limited earlier in the shift range where the regenerative braking force is stronger.

[0073] (6) The vehicle control device according to (1), wherein the predetermined threshold value is switched depending on the condition of the road surface on which the vehicle is traveling. According to this configuration, it is possible to adjust the timing for limiting the deceleration torque depending on the road surface condition such as the slope.

[0074] (7) The vehicle control device according to (1), which terminates the restriction when a brake operation on the vehicle is terminated or an accelerator operation is performed. According to this configuration, it is possible to remove the restriction on the deceleration torque depending on the operation state of the brake or accelerator.

[0075] (8) The vehicle control device according to (1), wherein braking force is compensated for by a hydraulic brake when the deceleration torque is limited. According to this configuration, even if the deceleration torque from the regenerative brake is insufficient, the hydraulic brake can compensate for it, thereby enabling safe braking switching.

[0076] (9) When the first power transmission path is in an engaged state, the first power transmission path is switched to a disengaged state in response to a vehicle speed of the vehicle falling below a predetermined speed threshold. The restriction is initiated before the first power transmission path is switched to an open state. A control device for a vehicle as described in (1). With this configuration, it is possible to suppress the occurrence of engine stall when sudden deceleration occurs while the motor clutch is in the disengaged state.

[0077] (10) The vehicle control device according to (9), wherein the engagement operation of the second power transmission path is initiated before the first power transmission path is disconnected. This configuration makes it possible to minimize the period during which power is not supplied from either the engine or the motor. [Explanation of symbols]

[0078] 100...Vehicle 101...Engine 102...Generator 103...Engine clutch 104...Drive shaft 105...Drive wheels (front wheels) 106...Motor clutch 107...Motor 108...ECU 109...Accelerator opening sensor 110...Brake sensor 111...Speed ​​sensor 112...Battery 113...Axle 114...Driven wheels (rear wheels)

Claims

1. A first power transmission path between a generator that operates as a regenerative brake, an engine, and a drive shaft and a vehicle control device that controls running of the vehicle by switching the connection / disconnection state of each of a second power transmission path between the rotating electric machine and the drive shaft, the first power transmission path is engaged; And when the second power transmission path is in an open state, In response to a brake operation amount for the vehicle exceeding a predetermined threshold, the deceleration torque by the regenerative brake is limited so that the drive torque applied to the drive shaft increases toward zero in accordance with a change in a preset lower limit torque. Vehicle control device.

2. the lower limit torque is derived using a fixed value and a suppression gain, The suppression gain varies depending on a brake operation amount for the vehicle. The vehicle control device according to claim 1 .

3. The vehicle control device according to claim 2 , wherein the suppression gain is set to a different value according to a plurality of shift ranges each having a different regenerative braking force.

4. The vehicle control device according to claim 1 , wherein the predetermined threshold value is set to a different value according to a plurality of shift ranges each having a different regenerative braking force.

5. The vehicle control device according to claim 4 , wherein the predetermined threshold value is set to a lower value for a shift range having a stronger regenerative braking force among the plurality of shift ranges.

6. The vehicle control device according to claim 1 , wherein the predetermined threshold value is changed depending on the condition of the road surface on which the vehicle is traveling.

7. The vehicle control device according to claim 1 , wherein the restriction is terminated when a brake operation on the vehicle is terminated or an accelerator operation is performed.

8. 2. The vehicle control device according to claim 1, wherein braking force is compensated for by a hydraulic brake when the deceleration torque is limited.

9. switching the first power transmission path to a disengaged state in response to a vehicle speed of the vehicle falling below a predetermined speed threshold while the first power transmission path is in an engaged state; The restriction is initiated before the first power transmission path is switched to an open state. The vehicle control device according to claim 1 .

10. The vehicle control device according to claim 9 , further comprising: a step of initiating an engagement operation of the second power transmission path before disconnecting the first power transmission path.

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