Vehicle control device

Abstract

To provide a vehicle control device capable of improving responsiveness of drive force.SOLUTION: A vehicle control device is mounted on a vehicle which comprises an engine, a clutch arranged between the engine and drive wheels, a first rotating electric machine connected to the drive wheels, a second rotation machine connected to the engine and a power storage device supplying electric power to the first rotation machine and the second rotating electric machine and has a first travel mode to travel with torque output from the first rotating electric machine and a second travel mode to travel with engine torque output from the engine and the torque output from the first rotating electric machine. The vehicle control device has a section 1 in which the engine is cranked with output of the second rotating electric machine during clutch engagement at the time of an engine start-up for transition from the first travel mode to the second travel mode and another section 2 in which drive force of the engine is assisted with output of the first rotating electric machine. The vehicle control device executes control to curb an increase in the torque of the first rotating electric machine in the section 1.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a hybrid vehicle that, when switching from electric driving mode to hybrid driving mode, assists in reducing engine start response delays by using a first rotating electric machine, which is a power source for driving the vehicle, in addition to a starter motor. Patent Document 2 discloses a technology in which the torque of a second rotating electric machine, which is a power source for driving the vehicle, is increased while the engine is started by the first rotating electric machine, and after the engine starts, the first rotating electric machine generates electricity, thereby further increasing the torque of the second rotating electric machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-241100 [Patent Document 2] Patent Publication No. 2021-109473 Summary of the Invention [Problem to be solved by the invention]

[0004] In the hybrid vehicle disclosed in Patent Document 1, most of the battery output is consumed by the starter motor to start the engine, and the output of the first rotating electric machine is equal to or lower than the steady-state output of the battery, resulting in small driving force compensation and a small assist effect for the delayed driving force response. Furthermore, in the technology disclosed in Patent Document 2, the torque of the second rotating electric machine is increased during engine start, which may delay engine start depending on the battery state and reduce driving force response.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a vehicle control device that can improve the responsiveness of driving force. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a vehicle control device according to the present invention includes an engine, a clutch provided on a power transmission path between the engine and drive wheels, a first rotating electric machine connected to the drive wheels, a second rotating electric machine connected to the engine, and an electric storage device that supplies electric power to the first rotating electric machine and the second rotating electric machine, and has two driving modes: a first driving mode in which the vehicle travels using torque output from the first rotating electric machine driven by electric power from the electric storage device with the clutch disengaged and the engine stopped; and a second driving mode in which the vehicle travels using torque output from the engine with the clutch engaged and the engine operated. a first driving mode in which the vehicle travels using a torque output from the first rotating electric machine driven by the power from the power storage device, and a second driving mode in which the vehicle travels using a torque output from the first rotating electric machine driven by the power from the power storage device, and the vehicle control device has a section 1 in which the engine is cranked using the output of the second rotating electric machine during a period from when the clutch is engaged at engine start to when the vehicle transitions from the first driving mode to the second driving mode, and a section 2 following section 1 in which the output of the first rotating electric machine assists the driving force of the engine, and is characterized in that control is performed to limit an increase in the torque of the first rotating electric machine in section 1.

[0007] This makes it possible to perform driving force compensation with an output of the first rotating electrical machine that is equal to or greater than the steady-state output of the power storage device before the clutch is engaged, thereby improving the responsiveness of the driving force.

[0008] In addition, in the above, if the elapsed time from the determination of the transition from the first driving mode to the second driving mode is less than a predetermined time, the output upper limit of the first rotating electric machine may be determined to be 0 in the first half of section 1, and the output upper limit of the first rotating electric machine in the second half of section 1 may be determined to be a value obtained by subtracting the output of the second rotating electric machine from the steady-state output of the storage device.

[0009] This makes it possible to improve the amount of driving force compensation by the first rotating electrical machine.

[0010] In addition, in the above, when the accelerator opening is smaller than a predetermined accelerator opening, when the vehicle speed is smaller than a predetermined vehicle speed, or when the synchronous rotation speed at the time of clutch engagement is smaller than a predetermined synchronous rotation speed, the sum of the required output of the first rotating electric machine and the required output of the second rotating electric machine in section 1 may be controlled to be the maximum output of the storage device.

[0011] This allows the first rotating electrical machine to perform driving force compensation from the start of the mode transition from the first traveling mode to the second traveling mode.

[0012] In the above, the section 1 may be a period until the engine speed reaches or exceeds a predetermined speed.

[0013] As a result, by performing cranking using the second rotating electrical machine until the engine is completely fired, it is possible to prevent failure to start the engine. [Effects of the Invention]

[0014] The vehicle control device according to the present invention has the advantage of being able to perform driving force compensation using the output of the first rotating electric machine that is equal to or greater than the steady-state output of the power storage device before the clutch is engaged, thereby improving the responsiveness of the driving force. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a vehicle according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing another example of the position of the clutch in the schematic configuration of the vehicle according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing another example of the position of the first rotating electric machine in the schematic configuration of the vehicle according to the first embodiment. [Figure 4]FIG. 4 is a timing chart showing switching from the BEV mode to the HEV mode. [Figure 5] FIG. 5 is a flowchart showing an outline of the required output determination control of the first rotating electric machine performed by the vehicle control device according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of control for determining the required output of the first rotating electric machine, which is performed by the control device for a vehicle according to the first embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the second embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the third embodiment. [Figure 9] FIG. 9 is a diagram showing a general MG torque characteristic. [Figure 10] FIG. 10 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the fourth embodiment. [Figure 11] FIG. 11 is a timing chart showing the timing when switching from the BEV mode to the HEV mode in the vehicle according to the fourth embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the fifth embodiment. [Figure 13] FIG. 13 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the sixth embodiment. [Figure 14] FIG. 14 is a timing chart showing the timing when switching from the BEV mode to the HEV mode in the vehicle according to the sixth embodiment. [Figure 15] FIG. 15 is a flowchart showing an example of control for determining a required output of the first rotating electric machine, which is performed by the control device in the vehicle according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Embodiment 1) A first embodiment of a vehicle equipped with a vehicle control device according to the present invention will be described below, although the present invention is not limited to this embodiment.

[0017] Fig. 1 is a diagram showing a schematic configuration of a vehicle 1 according to embodiment 1. As shown in Fig. 1, the vehicle 1 according to embodiment 1 includes an engine 2, a battery 3, a transmission 4, a clutch 5, a differential gear 6, front wheels 7, rear wheels 8, a first PCU 11, a second PCU 12, a plurality of rotating shafts 21, 22, 23, and 24, a front drive shaft 25, a rear drive shaft 26, a control device 30, a first rotating electric machine MG1, and a second rotating electric machine MG2.

[0018] A transmission 4 is disposed on the output side of the engine 2, and a crankshaft, which is the rotating shaft of the engine 2, is connected to a rotating shaft 22 of the transmission 4. The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine, and outputs torque according to the required driving force, such as the amount of accelerator pedal depression (accelerator opening) by the driver, by controlling the throttle opening and fuel injection amount.

[0019] The transmission 4 is disposed on the same axis as the engine 2, and transmits torque between the engine 2 and the first rotating electric machine MG16 and the rear wheels 8, which are drive wheels. The transmission 4 is a mechanism that can appropriately change the ratio of input rotation speed to output rotation speed, and can be configured using a stepped transmission or a continuously variable transmission that can continuously change the gear ratio. The transmission 4 is equipped with a clutch 5 that can transmit torque by engaging and can cut off torque transmission by disengaging, thereby establishing a neutral state.

[0020] The clutch 5 is connected to a rotating shaft 22 coupled to the crankshaft of the engine 2 and a rotating shaft 23 coupled to the rotor shaft of the first rotating electric machine MG1, and selectively transmits and cuts off power between the engine 2 and the first rotating electric machine MG1 (rear wheels 8). Furthermore, in the vehicle 1 according to this embodiment, the clutch 5 is not limited to being incorporated inside the transmission 4. For example, as shown in FIG. 2 , the first rotating electric machine MG1 may be disposed between the engine 2 and the transmission 4, and the clutch 5 may be disposed between the engine 2 and the first rotating electric machine MG1. In either case, disengaging the clutch 5 disconnects the engine 2 from the drive system of the vehicle 1. Engaging the clutch 5 connects the engine 2 to the drive system of the vehicle 1. The left and right front wheels 7 are connected to a front drive shaft 25 and are driven wheels that are driven by the rotational driving force of the rear wheels 8, which are drive wheels, to drive the vehicle 1. In the vehicle 1 according to the first embodiment, the first rotating electrical machine MG1 may be connected to the left and right front wheels 7 via left and right front drive shafts 25 so as to be able to transmit power as drive wheels, as shown in FIG.

[0021] The first rotating electric machine MG1 is connected to the left and right rear wheels 8 so as to be able to transmit power. The first rotating electric machine MG1 functions as a prime mover that is driven by a supply of electric power to output torque, and as a generator that is driven by external torque to generate electricity. That is, the first rotating electric machine MG1 is a motor-generator, and is configured, for example, by a permanent magnet synchronous motor or an induction motor. The first rotating electric machine MG1 is connected to a battery 3 via a first PCU 11, and the first rotating electric machine MG1 can be driven by electric power from the battery 3, which is an electricity storage device, to output torque (MG1 torque). The first rotating electric machine MG1 outputs torque according to a required driving force, such as the amount of depression of the accelerator pedal by the driver (accelerator opening). Furthermore, because the first rotating electric machine MG1 is connected to the rear wheels 8 so as to be able to transmit power, the first rotating electric machine MG1 can be driven as a generator by torque transmitted from the rear wheels 8, and the generated electricity can be stored in the battery 3.

[0022] A rotating shaft 24 serving as a rear propeller shaft is connected to the rotor shaft of the first rotating electric machine MG1. The rotating shaft 24 extends rearward from the first rotating electric machine MG1 in the longitudinal direction of the vehicle 1. A differential gear 6 is connected to the rotating shaft 24. Left and right rear wheels (drive wheels) 8 are connected to the differential gear 6 via left and right rear drive shafts 26.

[0023] The rotating shaft 21 of the second rotating electric machine MG2 is connected to the crankshaft of the engine 2. The rotating shaft 21 of the second rotating electric machine MG2 may be connected to the crankshaft of the engine 2 via a gear or a belt. The second rotating electric machine MG2 may be disposed between the engine 2 and the clutch 5. The second rotating electric machine MG2 is connected to the battery 3 via the second PCU 12, and can be driven by electric power from the battery 3 to output torque (MG2 torque). The second rotating electric machine MG2 functions as a starter motor that cranks the engine 2 using electric power from the battery 3.

[0024] The vehicle 1 according to this embodiment can be set to travel in either a BEV mode, which is a first travel mode, or an HEV mode, which is a second travel mode. The BEV mode is a travel mode in which the vehicle 1 travels using torque output from the first rotating electric machine MG1 driven by electric power from the battery 3, with the clutch 5 disengaged and the engine 2 stopped. The HEV mode is a travel mode in which the engine 2 is operated with the clutch 5 engaged, and the vehicle 1 travels using engine torque output from the engine 2 and torque output from the first rotating electric machine MG1 driven by electric power from the battery 3.

[0025] The control device 30 is a vehicle control device that controls the engine 2, the battery 3, the transmission 4, the clutch 5, the first PCU 11, the second PCU 12, the first rotating electric machine MG1, and the second rotating electric machine MG2. Various pieces of information necessary for driving control are input to the control device 30. Examples of this information include an ignition signal from an ignition switch, a shift position from a shift position sensor that detects the operating position of a shift lever, an accelerator opening from an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal by the driver, a brake pedal position from a brake pedal position sensor that detects the amount of depression of the brake pedal by the driver, an engine speed from an engine speed sensor, an MG1 rotation speed from an MG1 rotation speed sensor that detects the rotation speed of the first rotating electric machine MG1, an MG2 rotation speed from an MG2 rotation speed sensor that detects the rotation speed of the second rotating electric machine MG2, and a vehicle speed from a vehicle speed sensor.

[0026] The vehicle 1 according to the first embodiment has, when switching from the BEV mode to the HEV mode, a section 1 in which the engine 2 is cranked by the output of the second rotating electric machine MG2 during a period from engagement of the clutch 5 at engine start when transitioning from the BEV mode to the HEV mode, and a section 2 following the section 1 in which the driving force of the engine 2 is assisted by the output of the first rotating electric machine MG1. In the vehicle 1 according to the first embodiment, the control device 30 can perform control to limit an increase in torque of the first rotating electric machine MG1 during the section 1 during the mode transition. In other words, in the vehicle 1 according to the first embodiment, the section 1 is the period during engine start when an output request to the second rotating electric machine MG2 is essential for cranking during the mode transition from the BEV mode to the HEV mode, and the section 2 is the period from after completion of engine start determination to completion of the mode transition to the HEV mode. In the vehicle 1 according to the first embodiment, the control device 30 can perform control to switch the output request to the first rotating electric machine MG1 between the section 1 and the section 2. The engine start completion determination (end determination of section 1) can be determined, for example, when the engine speed is equal to or greater than a predetermined value (engine speed ≧ predetermined value). As a result, engine start failure can be suppressed by performing cranking with the second rotating electrical machine MG2 until the engine is fully activated. For example, in the timing chart for switching from BEV mode to HEV mode shown in FIG. 4, during the transition from BEV mode to HEV mode, the upper limit of the output of the first rotating electrical machine MG1 is set to 0 in section 1, and the upper limit of the output of the first rotating electrical machine MG1 is set to the maximum battery output in section 2.

[0027] Fig. 5 is a flowchart showing an outline of the control for determining the required output of the first rotating electrical machine MG1, which is performed by the control device 30 of the vehicle 1 according to the embodiment 1. In the following description, the control for determining the required output of the first rotating electrical machine MG1, which is performed by the control device 30 in the series of steps shown in Fig. 5, will also be referred to as "this control."

[0028] First, the control device 30 executes a control execution determination step (step S1). In this control execution determination step, it determines whether or not to execute required output determination control for the first rotating electrical machine MG1 based on the accelerator opening, vehicle speed, synchronous rotation speed, etc. Next, the control device 30 executes a mode transition section determination step (step S2). In this mode transition section determination step, the current section during mode transition from BEV mode to HEV mode is determined based on the engine rotation speed, synchronous rotation speed, timer, etc. Next, the control device 30 executes an MG1 output upper limit determination step (step S3). In this MG1 output upper limit determination step, the output upper limit of the first rotating electrical machine MG1 is determined according to the section during mode transition from BEV mode to HEV mode. Next, the control device 30 executes an MG1 required output determination step (step S4). In this MG1 required output determination step, the required output of the first rotating electrical machine MG1 is determined based on the output upper limit of the first rotating electrical machine MG1 and the required driving force.

[0029] 6 is a flowchart showing an example of control for determining the required output of the first rotating electrical machine MG1, which is performed by the control device 30 of the vehicle 1 according to the first embodiment. In FIG. 6, the process of step S11 and the process of step S12 are included in a step for determining whether to perform control (step S1). In FIG. 6, the process of step S21 is included in a step for determining a section during mode transition (step S2). In FIG. 6, the process of step S31 and the process of step S32 are included in a step for determining the upper limit of the output of MG1 (step S3). In FIG. 6, the process of step S41 is included in a step for determining the required output of MG1 (step S4).

[0030] First, the control device 30 reads the vehicle driving state (step S11). Next, the control device 30 determines whether or not the vehicle is in a mode transition from BEV mode to HEV mode (step S12). If the control device 30 determines that the vehicle is not in a mode transition from BEV mode to HEV mode (No in step S12), the control device 30 ends the series of required output determination control for the first rotating electrical machine MG1. On the other hand, if the control device 30 determines that the vehicle is in a mode transition from BEV mode to HEV mode (Yes in step S12), the control device 30 determines whether or not the engine is starting (step S21). If the control device 30 determines that the engine is starting (Yes in step S2), the control device 30 determines that the section in which the mode transition is occurring is section 1, and sets the output upper limit of the first rotating electrical machine MG1 to 0 (step S31). Next, the control device 30 determines the required output of the first rotating electrical machine MG1 based on the determined output upper limit of the first rotating electrical machine MG1 and the required driving force (step S41). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0031] Furthermore, if the control device 30 determines in step S21 that the engine is not starting (No in step S21), it determines that the section during mode transition is section 2 and sets the output upper limit of the first rotating electrical machine MG1 to the maximum battery output (step S32). Next, the control device 30 determines the required output of the first rotating electrical machine MG1 from the determined output upper limit of the first rotating electrical machine MG1 and the required driving force (step S41). Thereafter, the control device 30 ends the series of required output determination controls for the first rotating electrical machine MG1.

[0032] In the vehicle 1 according to the first embodiment, the required output of the first rotating electric machine MG1 is switched depending on the section (section 1 and section 2) during the mode transition from the BEV mode to the HEV mode. As a result, in the vehicle 1 according to the first embodiment, it is possible to realize effective driving force compensation by the first rotating electric machine MG1 for the response delay of the driving force (acceleration) without increasing the battery capacity (increasing the cost).

[0033] (Embodiment 2) A vehicle control device according to a second embodiment of the present invention will be described below. Note that in this embodiment, the same descriptions as those in the first embodiment will be omitted as appropriate.

[0034] In the vehicle 1 according to the second embodiment, this control is not always performed during the mode transition from the BEV mode to the HEV mode. That is, in the vehicle 1 according to the second embodiment, this control is performed when the driver's acceleration request is high. Then, under conditions where conventional control is more advantageous than this control (for example, when the driver's acceleration request is not high), conventional control is performed to perform driving force compensation with the first rotating electric machine MG1 from the start of the mode transition. Note that, in the conventional control, for example, in Section 1 during the mode transition, control is performed so that the sum of the required output of the first rotating electric machine MG1 and the required output of the second rotating electric machine MG2 becomes the maximum battery output. Then, in Section 2 during the mode transition, the required output of the second rotating electric machine MG2 is set to 0, and the required output of the first rotating electric machine MG1 is controlled to maintain the required output of Section 1. That is, in the conventional control, the required output of the first rotating electric machine MG1 is kept the same between Section 1 and Section 2 during the mode transition from the BEV mode to the HEV mode.

[0035] Fig. 7 is a flowchart showing an example of required output determination control of the first rotating electrical machine MG1 performed by the control device 30 in the vehicle 1 according to the embodiment 2. In Fig. 7, the process of step S11, the process of step S12, and the process of step S13 are included in the control execution determination step (step S1).

[0036] First, the control device 30 reads the vehicle driving state (step S11). Next, the control device 30 determines whether or not the vehicle is in a mode transition from BEV mode to HEV mode (step S12). If the control device 30 determines that the vehicle is not in a mode transition from BEV mode to HEV mode (No in step S12), the control device 30 terminates the required output determination control for the first rotating electrical machine MG1. On the other hand, if the control device 30 determines that the vehicle is in a mode transition from BEV mode to HEV mode (Yes in step S12), the control device 30 determines whether or not the accelerator opening is equal to or greater than a predetermined value A (accelerator opening ≧ predetermined value A) (step S13). The predetermined value A is, for example, a predetermined accelerator opening. If the control device 30 determines that the accelerator opening is equal to or greater than the predetermined value A (Yes in step S13), the control device 30 performs a step of determining a section during mode transition (step S2). Thereafter, the control device 30 executes a step of determining an upper limit of the output of the MG1 (step S3) and a step of determining a required output of the MG1 (step S4), and ends a series of required output determination control for the first rotating electrical machine MG1.

[0037] Furthermore, when the control device 30 determines that the accelerator opening is less than a predetermined value A (accelerator opening<predetermined value A), it performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0038] In the vehicle 1 according to the second embodiment, when the driver's acceleration request is high, this control can be performed in a region where the deviation between the requested driving force and the driving force compensation at the first rotating electrical machine MG1 is large in conventional control.

[0039] (Embodiment 3) A vehicle control device according to a third embodiment of the present invention will be described below. Note that in this embodiment, the same descriptions as those in the first embodiment will be omitted as appropriate.

[0040] In the vehicle 1 according to the third embodiment, this control is not always performed during the mode transition from BEV mode to HEV mode, but is performed when there is a high demand for acceleration from the driver and in an area where the driving force compensation of the first rotating electric machine MG1 becomes small under conventional control, and the conventional control is performed under conditions where the conventional control is more advantageous than this control.

[0041] Fig. 8 is a flowchart showing an example of required output determination control for the first rotating electrical machine MG, which is performed by the control device 30 in the vehicle 1 according to the third embodiment. In Fig. 8, the processes of steps S11, S12, S13, and S14 are included in the control execution determination step (step S1). Fig. 9 is a diagram showing a general MG torque characteristic.

[0042] First, the control device 30 reads the vehicle running state (step S11). Next, the control device 30 determines whether or not the vehicle is currently in mode transition from BEV mode to HEV mode (step S12). If the control device 30 determines that the vehicle is not currently in mode transition from BEV mode to HEV mode (No in step S12), it ends the required output determination control for the first rotating electrical machine MG1.

[0043] On the other hand, if the control device 30 determines that the mode is being transitioned from BEV mode to HEV mode (Yes in step S12), it determines whether the accelerator opening is equal to or greater than a predetermined value A (accelerator opening ≧ predetermined value A) (step S13). If the control device 30 determines that the accelerator opening is less than the predetermined value A (accelerator opening<predetermined value A), it performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0044] On the other hand, when the control device 30 determines that the accelerator opening is equal to or greater than a predetermined value A (Yes in step S13), it determines whether or not the current vehicle speed is equal to or greater than a predetermined value B (vehicle speed≧predetermined value B) (step S14). The predetermined value B is, for example, a predetermined vehicle speed. The vehicle speed may be determined based on the detection result of a vehicle speed sensor, or may be determined from the torque of the first rotating electrical machine MG1 (MG torque) based on the relationship between the MG rotational speed (e.g., the rotational speed of the first rotating electrical machine MG1) and the MG torque (e.g., the torque of the first rotating electrical machine MG1) shown in FIG. 9, or may be determined from the rotational speed of the first rotating electrical machine MG1. The vehicle speed may also be determined from the rotational speed of the first rotating electrical machine MG1 (MG rotational speed) and the gear position or gear ratio of the drive train (transmission 4).

[0045] When the control device 30 determines that the current vehicle speed is equal to or greater than a preset value B (vehicle speed≧predetermined value B) (Yes in step S14), it executes a step of determining a section during mode transition (step S2). Thereafter, the control device 30 executes a step of determining an upper limit of the MG1 output (step S3) and a step of determining the MG1 required output (step S4), thereby completing a series of required output determination controls for the first rotating electrical machine MG1.

[0046] On the other hand, when the control device 30 determines that the current vehicle speed is less than the preset value B (vehicle speed<predetermined value B) (No in step S14), the control device 30 performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0047] The control device 30 according to the embodiment can perform this control in a region where the driving force compensation of the first rotating electrical machine MG1 is small under conventional control and the deviation between the required driving force and the driving force compensation of the first rotating electrical machine MG1 is large.

[0048] (Embodiment 4) A fourth embodiment of the vehicle control device according to the present invention will be described below. Note that in this embodiment, the same descriptions as in the first embodiment will be omitted as appropriate.

[0049] In the vehicle 1 according to the fourth embodiment, this control is not always performed during the mode transition from BEV mode to HEV mode, but rather, when the driver's demand for acceleration is high, this control is performed in an area where the driving force compensation of the first rotating electric machine MG1 becomes small under conventional control and where the time required for mode transition is long, and the conventional control is performed under conditions where the conventional control is more advantageous than this control.

[0050] Fig. 10 is a flowchart showing an example of required output determination control for the first rotating electrical machine MG1 performed by the control device 30 in the vehicle 1 according to the fourth embodiment. In Fig. 10, the processes of steps S11, S12, S13, S14, and S15 are included in the control execution determination step (step S1). Fig. 11 is a diagram showing a timing chart when switching from the BEV mode to the HEV mode in the vehicle 1 according to the fourth embodiment.

[0051] First, the control device 30 reads the vehicle running state (step S11). Next, the control device 30 determines whether or not the vehicle is currently in mode transition from BEV mode to HEV mode (step S12). If the control device 30 determines that the vehicle is not currently in mode transition from BEV mode to HEV mode (No in step S12), it ends the required output determination control for the first rotating electrical machine MG1.

[0052] On the other hand, if the control device 30 determines that the mode is being transitioned from BEV mode to HEV mode (Yes in step S12), it determines whether the accelerator opening is equal to or greater than a predetermined value A (accelerator opening ≧ predetermined value A) (step S13). If the control device 30 determines that the accelerator opening is less than the predetermined value A (accelerator opening<predetermined value A), it performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0053] On the other hand, if the control device 30 determines that the accelerator opening is equal to or greater than a predetermined value A (Yes in step S13), it determines whether the current vehicle speed is equal to or greater than a predetermined value B (vehicle speed≧predetermined value B) (step S14). If the control device 30 determines that the current vehicle speed is less than the predetermined value B (vehicle speed<predetermined value B) (No in step S14), it performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0054] On the other hand, when the control device 30 determines that the current vehicle speed is equal to or greater than a predetermined value B (vehicle speed ≧ predetermined value B) (Yes in step S14), it determines whether the synchronous rotation speed is equal to or greater than a predetermined value C (synchronous rotation speed ≧ predetermined value C) (step S15). The synchronous rotation speed may be determined, for example, from the gear position or gear ratio of the transmission 4. The predetermined value C is, for example, a predetermined synchronous rotation speed.

[0055] When the control device 30 determines that the synchronous rotation speed is equal to or greater than a preset predetermined value C (synchronous rotation speed≧predetermined value C) (Yes in step S15), it executes a step of determining a section during mode transition (step S2). Thereafter, the control device 30 executes a step of determining an upper limit of the MG1 output (step S3) and a step of determining the MG1 required output (step S4), thereby completing a series of required output determination controls for the first rotating electrical machine MG1.

[0056] On the other hand, when the control device 30 determines that the synchronous rotation speed is less than the preset value C (synchronous rotation speed<predetermined value C) (No in step S15), the control device 30 performs conventional control (step S5). Thereafter, the control device 30 ends the series of control steps for determining the required output of the first rotating electrical machine MG1.

[0057] In the vehicle 1 according to the fourth embodiment, as shown in FIG. 11, when the time required for mode transition is short, the duration of section 2 becomes short and the effect of driving force compensation in this control becomes small, conventional control can be implemented.

[0058] (Embodiment 5) Hereinafter, a fifth embodiment of the vehicle control device according to the present invention will be described. Note that in this embodiment, the same descriptions as those in the first embodiment will be omitted as appropriate.

[0059] In the vehicle 1 according to the fifth embodiment, control is performed to use up the steady-state output of the battery in Section 1 during the mode transition from the BEV mode to the HEV mode.

[0060] Fig. 12 is a flowchart showing an example of control for determining the required output of the first rotating electrical machine MG1, which is performed by the control device 30 in the vehicle 1 according to the fifth embodiment. In Fig. 12, the process of step S21 is included in the step of determining the section during mode transition (step S2). Also, in Fig. 12, the processes of steps S32 and S33 are included in the step of determining the upper limit of the output of MG1 (step S3).

[0061] First, the control device 30 performs a determination step of control implementation (step S1). Next, the control device 30 determines whether the engine is starting or not (step S21). If the control device 30 determines that the engine is starting (Yes in step S21), the control device 30 determines that the section during mode transition is section 1, and determines the output upper limit of the first rotating electrical machine MG1 so as to satisfy the relationship "MG1 output upper limit = battery steady output - MG2 output" (step S33). Next, the control device 30 performs a determination step of the MG1 required output (step S4). Thereafter, the control device 30 ends a series of control steps for determining the required output of the first rotating electrical machine MG1.

[0062] On the other hand, if the control device 30 determines in step S21 that the engine is not starting (No in step S21), it determines that the section during mode transition is section 2, and determines the output upper limit of the first rotating electrical machine MG1 so as to satisfy the relationship "MG1 output upper limit = battery maximum output" (step S32). Next, the control device 30 performs a step of determining the MG1 required output (step S4). Thereafter, the control device 30 ends the series of control operations for determining the required output of the first rotating electrical machine MG1.

[0063] In the vehicle 1 according to the fifth embodiment, the steady-state output of the battery can be used up in section 1, and the effect of the driving force compensation by the first rotating electric machine MG1 can be made greater than when there is excess steady-state output of the battery in section 1.

[0064] (Embodiment 6) A sixth embodiment of the vehicle control device according to the present invention will be described below. Note that in this embodiment, the same descriptions as those in the first embodiment will be omitted as appropriate.

[0065] In the vehicle 1 according to the sixth embodiment, during the mode transition from the BEV mode to the HEV mode, control is performed to use up the maximum output of the battery for an allowable time while the engine is started.

[0066] Fig. 13 is a flowchart showing an example of control for determining a required output of the first rotating electrical machine MG1, which is performed by the control device 30 in the vehicle 1 according to the sixth embodiment. In Fig. 13, the process of step S21 and the process of step S21 are included in a section determination step during mode transition (step S2). In Fig. 13, the process of step S31, the process of step S32, and the process of step S33 are included in a step for determining an upper limit of the output of MG1 (step S3).

[0067] FIG. 14 is a timing chart showing the timing when switching from the BEV mode to the HEV mode in the vehicle 1 according to the sixth embodiment.

[0068] First, the control device 30 executes a control execution determination step (step S1). Next, the control device 30 determines whether the engine is starting (step S21). If the control device 30 determines that the engine is starting (Yes in step S21), the control device 30 determines whether the elapsed time since the determination of the transition from the BEV mode to the HEV mode is equal to or less than a predetermined value D (the elapsed time≦predetermined value D) (step S22). Note that the determination value of the elapsed time is preferably determined, for example, according to the synchronous rotation speed at the time of engine rotation synchronization, in which the rotation speed of the engine 2 (rotating shaft 22) is synchronized with the rotation speed of the output shaft (rotating shaft 23) of the transmission 4. This is because the time required for mode transition increases as the synchronous rotation speed increases, and therefore it is preferable to set the determination value according to the time required for mode transition. Furthermore, the predetermined value D is, for example, a predetermined time.

[0069] When the control device 30 determines that the elapsed time is equal to or less than a preset value D (the elapsed time≦predetermined value D) (Yes in step S22), the control device 30 determines the section during mode transition as section 1-1, which is the first half of section 1, and determines the output upper limit of the first rotating electrical machine MG1 so as to satisfy the relationship "MG1 output upper limit=0" (step S31). Next, the control device 30 executes a step of determining the MG1 required output (step S4). Thereafter, the control device 30 ends the series of control operations for determining the required output of the first rotating electrical machine MG1.

[0070] On the other hand, if the control device 30 determines in step S22 that the elapsed time is longer than the preset value D (the elapsed time>predetermined value D) (No in step S22), it determines the section during mode transition as section 1-2, which is the latter half of section 1, and determines the output upper limit of the first rotating electrical machine MG1 so as to satisfy the relationship "MG1 output upper limit=battery steady-state output-MG2 output" (step S33). Next, the control device 30 performs a step of determining the MG1 required output (step S4). Thereafter, the control device 30 ends the series of control operations for determining the required output of the first rotating electrical machine MG1.

[0071] Furthermore, if the control device 30 determines in step S21 that the engine is not starting (No in step S21), it determines that the section during mode transition is section 2, and determines the output upper limit of the first rotating electrical machine MG1 so as to satisfy the relationship "MG1 output upper limit = battery maximum output" (step S32). Next, the control device 30 executes a step of determining the MG1 required output (step S4). Thereafter, the control device 30 ends the series of control operations for determining the required output of the first rotating electrical machine MG1.

[0072] In the vehicle 1 of embodiment 6, during the mode transition from BEV mode to HEV mode, the maximum output of the battery is used up for the allowable time while the engine is started, thereby making maximum use of the driving force compensation by the first rotating electric machine MG1.

[0073] (Embodiment 7) A seventh embodiment of the vehicle control device according to the present invention will be described below. Note that in this embodiment, the same descriptions as in the first embodiment will be omitted as appropriate.

[0074] In the vehicle 1 according to the seventh embodiment, control is performed to determine the output of the first rotating electrical machine MG1 in response to a driving force request within the range of the MG1 output upper limit determined in the step of determining the MG1 output upper limit (step S3).

[0075] Fig. 15 is a flowchart showing an example of control for determining the required output of the first rotating electrical machine MG1, which is performed by the control device 30 in the vehicle 1 according to the seventh embodiment. In Fig. 15, the process of step S42, the process of step S43, and the process of step S44 are included in the step of determining the required output of MG1 (step S4).

[0076] First, the control device 30 executes a step of determining whether to perform control (step S1). Next, the control device 30 executes a step of determining a section during mode transition (step S2). Next, the control device 30 executes a step of determining an upper limit of the MG1 output (step S3).

[0077] Next, the control device 30 determines whether or not the driving force request is greater than or equal to the output upper limit of the first rotating electric machine MG1 (driving force request ≥ MG1 output upper limit) (step S42). When the control device 30 determines that the driving force request is greater than or equal to the output upper limit of the first rotating electric machine MG1 (driving force request ≥ MG1 output upper limit) (Yes in step S42), it determines the required output of the first rotating electric machine MG1 to be the output upper limit of the first rotating electric machine MG1 (MG1 required output = MG1 output upper limit) (step S43). Thereafter, the control device 30 ends a series of control for determining the required output of the first rotating electric machine MG1.

[0078] On the other hand, when the control device 30 determines that the driving force request is less than the output upper limit of the first rotating electric machine MG1 (driving force request < MG1 output upper limit) (No in step S42), it determines the required output of the first rotating electric machine MG1 to be the driving force request (MG1 required output = driving force request) (step S44). Thereafter, the control device 30 ends a series of control for determining the required output of the first rotating electric machine MG1.

[0079] In the vehicle 1 according to the seventh embodiment, it is possible to determine an appropriate required output of the first rotating electric machine MG1 within the range of the MG1 output upper limit and perform driving force compensation by the first rotating electric machine MG1. When power supply from the battery to devices other than the first rotating electric machine MG1 and the second rotating electric machine MG2 is essential, the output upper limit of the first rotating electric machine MG1 may be subtracted by that amount of power.

Explanation of Signs

[0080] 1 Vehicle 2 Engine 3 Battery 4 Transmission 5 Clutch 6 Differential gear 7 Front wheel 8 Rear wheel 11 First PCU 12 Second PCU 21, 22, 23, 24 Rotating shafts 25 Front drive shaft 26 Rear drive shaft 30 Control device MG1 First rotating electric machine MG2 No. 2 rotating electric machine

Claims

1. The engine and a clutch provided on a power transmission path between the engine and the drive wheels; a first rotating electric machine connected to the drive wheels; a second rotating electric machine connected to the engine; an electric storage device that supplies electric power to the first rotating electric machine and the second rotating electric machine; Equipped with a first running mode in which the vehicle runs using torque output from the first rotating electric machine driven by electric power from the power storage device while the clutch is released and the engine is stopped; a second traveling mode in which the engine is operated with the clutch engaged, and the vehicle travels using engine torque output by the engine and torque output by the first rotating electric machine driven by electric power from the power storage device; A vehicle control device mounted on a vehicle having a period from the first traveling mode to the second traveling mode until the clutch is engaged at the time of starting the engine, the period including a first period in which the engine is cranked by the output of the second rotating electric machine, and a second period in which the driving force of the engine is assisted by the output of the first rotating electric machine, the period being after the first period in which the engine is cranked by the output of the first rotating electric machine; A vehicle control device characterized by controlling the output upper limit of the first rotating electric machine in section 1 to a value smaller than the output upper limit of the first rotating electric machine in section 2, thereby limiting the torque increase of the first rotating electric machine in section 1.

2. 2. The vehicle control device according to claim 1, characterized in that, when the elapsed time from the determination of the transition from the first driving mode to the second driving mode is equal to or less than a predetermined time, the output upper limit of the first rotating electric machine is determined to be 0 in the first half of the section 1, and the output upper limit of the first rotating electric machine in the second half of the section 1 is determined to be a value obtained by subtracting the output of the second rotating electric machine from the steady-state output of the storage device.

3. 2. The vehicle control device according to claim 1, wherein when the accelerator opening is smaller than a predetermined accelerator opening, when the vehicle speed is smaller than a predetermined vehicle speed, or when the synchronous rotation speed at the time of clutch engagement is smaller than a predetermined synchronous rotation speed, the vehicle control device controls the sum of the required output of the first rotating electric machine and the required output of the second rotating electric machine in section 1 to be the maximum output of the storage device.

4. 4. The vehicle control device according to claim 1, wherein the first period is a period until the engine speed reaches or exceeds a predetermined speed.

Images