Vehicle control devices

Abstract

To provide a vehicle control apparatus which can switch a traveling mode appropriately to an engine mode.SOLUTION: A travelling mode of a hybrid vehicle comprises: a motor mode in which an electric motor is driven with a clutch mechanism disengaged; and an engine mode in which the electric motor is driven with the clutch mechanism engaged. In a case of switching a traveling mode from the motor mode to the engine mode in response to an increase in requested driving force from a first driving force to a second driving force resulting from an operation of an accelerator, the control system starts up the engine and engages the clutch mechanism while controlling the electric motor based on a transition driving force larger than the first driving force. After a lapse of a delay time from completion of starting up of the engine and engaging the clutch mechanism, the control system controls the electric motor and the engine based on the second driving force larger than the transition driving force.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a vehicle control device provided in a hybrid vehicle.

Background Art

[0002] Hybrid vehicles have an engine and an electric motor as power sources (see Patent Documents 1 to 3). In addition, as driving modes, a motor mode in which the vehicle is driven using the electric motor and an engine mode in which the vehicle is driven using the engine are set in the hybrid vehicle. In the engine mode, it is possible to drive the vehicle using both the engine and the electric motor, and it is also possible to drive the vehicle using only the engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to switch the driving mode to the engine mode, it is necessary not only to start the engine but also to engage a clutch that transmits engine torque. Therefore, when the target driving force increases by depressing the accelerator pedal and the driving mode is switched from the motor mode to the engine mode, it has been difficult to immediately output engine torque. That is, when switching the driving mode to the engine mode, a deviation occurs between the target driving force and the actual driving force due to a temporary shortage of engine torque, and it has been difficult to appropriately switch to the engine mode.

[0005] The objective of the present invention is to appropriately switch to the engine mode. [Means for solving the problem]

[0006] A vehicle control device according to one embodiment is a vehicle control device provided in a hybrid vehicle, comprising: an electric motor connected to at least one of a first wheel and a second wheel; an engine connected to at least one of the first wheel and the second wheel via a power transmission path; a clutch mechanism provided in the power transmission path; a torque converter provided in the power transmission path; and a processor and memory communicated with each other, comprising a control system for controlling the electric motor, the engine and the clutch mechanism. do. The driving modes of the aforementioned hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. ru. The control system, when the required driving force increases from the first driving force to the second driving force due to accelerator operation and the driving mode is switched from the motor mode to the engine mode, controls the electric motor based on a transition driving force greater than the first driving force, starts the engine and engages the clutch mechanism, and after a delay time has elapsed since the engine started and the clutch mechanism was engaged, controls the electric motor and the engine based on the second driving force greater than the transition driving force. The control system sets the delay time to be shorter as the amount of accelerator operation increases. Another embodiment of the vehicle control device is a vehicle control device provided in a hybrid vehicle, and includes an electric motor connected to at least one of a first wheel and a second wheel, an engine connected to at least one of the first wheel and the second wheel via a power transmission path, a clutch mechanism provided in the power transmission path, a torque converter provided in the power transmission path, and a processor and memory that are communicated with each other, and a control system that controls the electric motor, the engine and the clutch mechanism. The driving modes of the hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. The control system, when the required driving force increases from a first driving force to a second driving force due to accelerator operation and the driving mode is switched from the motor mode to the engine mode, controls the electric motor based on a transition driving force greater than the first driving force, starts the engine and engages the clutch mechanism, and after a delay time has elapsed since the engine started and the clutch mechanism was engaged, controls the electric motor and the engine based on a second driving force greater than the transition driving force. The transition driving force is the driving force obtained when the electric motor is controlled to the powered state at its upper limit torque. Another embodiment of the vehicle control device is a vehicle control device provided in a hybrid vehicle, and includes an electric motor connected to at least one of a first wheel and a second wheel, an engine connected to at least one of the first wheel and the second wheel via a power transmission path, a clutch mechanism provided in the power transmission path, a torque converter provided in the power transmission path, and a processor and memory that are communicated with each other, and a control system that controls the electric motor, the engine and the clutch mechanism. The driving modes of the hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. The control system controls the electric motor based on a transitional driving force greater than the first driving force when the required driving force increases from the first driving force to the second driving force due to accelerator operation, and switches the driving mode from the motor mode to the engine mode. The system then starts the engine and engages the clutch mechanism, and after a delay time has elapsed since the engine has started and the clutch mechanism has engaged, it controls the electric motor and the engine based on the second driving force greater than the transitional driving force. The control system controls the electric motor and the engine based on a driving force that gradually increases from the transitional driving force to the second driving force, and increases the rate at which the driving force increases from the transitional driving force to the second driving force as the accelerator operation amount increases. [Effects of the Invention]

[0007] In one embodiment, the vehicle control device controls the electric motor and engine based on a second driving force greater than the transition driving force, after a delay time has elapsed following the completion of engine starting and clutch engagement. This allows for appropriate switching to engine mode. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of a hybrid vehicle equipped with a vehicle control device, which is one embodiment of the present invention. [Figure 2] This diagram shows an example of the configuration of a vehicle control system. [Figure 3] This diagram shows an example of the basic structure of each control unit. [Figure 4] This diagram shows the status of EV mode. [Figure 5] This figure shows the status of HEV mode. [Figure 6] This is a driving mode map showing an example of the operating range for EV mode and HEV mode. [Figure 7] This flowchart shows an example of the procedure for executing the driving mode switching control. [Figure 8] This flowchart shows an example of the procedure for executing the driving mode switching control. [Figure 9] This figure shows an example of the relationship between delay time and throttle opening. [Figure 10] This figure shows an example of the relationship between the rate of change in driving force and the accelerator opening. [Figure 11] This is a timing chart showing the execution status of the driving mode switching control. [Figure 12] This is a timing chart showing a magnified portion of the timing chart shown in Figure 11. [Figure 13] This figure shows other examples of powertrain configurations. [Figure 14] This figure shows other examples of powertrain configurations. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, identical or substantially identical components and elements will be denoted by the same reference numerals, and repeated descriptions will be omitted.

[0010] [Overall Configuration] FIG. 1 is a diagram showing a configuration example of a hybrid vehicle 11 equipped with a vehicle control device 10 according to an embodiment of the present invention. As shown in FIG. 1, the hybrid vehicle 11 is equipped with a power train 14 including an engine 12 and a transmission 13. A motor generator (electric motor) 15 is provided in the transmission 13 of this power train 14. Further, a rear wheel (first wheel) 19r is connected to the output shaft 16 of the transmission 13 via a propeller shaft 17 and a differential mechanism 18. Note that the power train 14 shown in the figure is a rear-wheel drive power train for driving the rear wheel 19r, but it is not limited to this. For example, it may be a front-wheel drive power train for driving the front wheel (second wheel) 19f, or it may be an all-wheel drive power train for driving both the front wheel 19f and the rear wheel 19r.

[0011] FIG. 2 is a diagram showing a configuration example of the vehicle control device 10. As shown in FIG. 2, the power train 14 is provided with a continuously variable transmission mechanism 23 including a primary pulley 20, a secondary pulley 21, and a drive chain 22. The engine 12 is connected to one side of the primary shaft 24 that supports the primary pulley 20 via a forward clutch (clutch mechanism) 25 and a torque converter 26. Further, the rotor 15r of the motor generator 15 is connected to the other side of the primary shaft 24 that supports the primary pulley 20. Furthermore, a rear wheel 19r is connected to the secondary shaft 27 that supports the secondary pulley 21 via the output shaft 16, the propeller shaft 17, and the differential mechanism 18. Note that the forward clutch 25 is a clutch that constitutes a part of a forward and reverse switching mechanism including a planetary gear train or the like.

[0012] The engine 12 and the rear wheels 19r are connected via a power transmission path 30 consisting of a torque converter 26, a forward clutch 25, a continuously variable transmission mechanism 23, a propeller shaft 17, and a differential mechanism 18. In the configuration example shown in Figure 2, the power transmission path 30 consists of a crankshaft 31, a torque converter 26, a turbine shaft 32, a forward clutch 25, a primary shaft 24, a continuously variable transmission mechanism 23, a secondary shaft 27, an output shaft 16, a propeller shaft 17, and a differential mechanism 18.

[0013] As mentioned above, the power transmission path 30 connecting the engine 12 and the rear wheel 19r is equipped with a torque converter 26 and a forward clutch 25. The torque converter 26 is positioned between the engine 12 and the forward clutch 25. Furthermore, a motor generator 15 is connected to the primary shaft 24 that constitutes the power transmission path 30. In other words, the motor generator 15 is connected to the rear wheel 19r via the power transmission path 30 from the input side of the continuously variable transmission mechanism 23.

[0014] The intake manifold 40 of the engine 12 is equipped with a throttle valve 41 for adjusting the amount of intake air. The engine 12 is also equipped with an injector 42 for injecting fuel into the intake port and cylinder, and an ignition system 43 consisting of an igniter and spark plugs. Furthermore, the engine 12 is equipped with an engine speed sensor 44 for detecting the engine speed, which is the rotational speed of the crankshaft 31. In addition, to control the torque output from the engine 12 (hereinafter referred to as engine torque), an electronic control unit, the engine control unit CU1, is connected to the throttle valve 41, injector 42, and ignition system 43, etc.

[0015] To control the forward clutch 25 and continuously variable transmission mechanism 23 of the powertrain 14, the powertrain 14 is provided with a valve unit 45 consisting of multiple electromagnetic valves and oil passages. An oil pump 46, driven by the engine 12 or motor, is connected to the valve unit 45. The hydraulic fluid discharged from the oil pump 46 is supplied to the forward clutch 25 and continuously variable transmission mechanism 23, etc., with the supply destination and pressure controlled by the valve unit 45. Furthermore, to control the operating state of the forward clutch 25, etc., via the valve unit 45, an electronically controlled transmission control unit CU2 is connected to the valve unit 45. In addition, a primary rotation sensor 47 for detecting the primary rotation speed, which is the rotational speed of the primary pulley 20, and a secondary rotation sensor 48 for detecting the secondary rotation speed, which is the rotational speed of the secondary pulley 21 are connected to the transmission control unit CU2. A turbine rotation sensor 49 for detecting the turbine rotation speed, which is the rotational speed of the turbine shaft 32, is also connected to the transmission control unit CU2.

[0016] A battery module 51 is connected to the stator 15s of the motor generator 15 via an inverter 50. The battery module 51 incorporates multiple battery cells 53 that constitute a high-voltage battery 52. ​​Furthermore, the battery module 51 is equipped with a main relay 54 that controls the connection of the high-voltage battery 52, and a battery sensor 55 that detects the charge / discharge current, terminal voltage, and temperature of the high-voltage battery 52. ​​An electronic control unit, the battery control unit CU3, is also connected to the battery module 51. The battery control unit CU3 has the function of monitoring the charge / discharge of the high-voltage battery 52 and controlling the main relay 54, etc. The battery control unit CU3 also has the function of calculating the State of Charge (SOC) of the high-voltage battery 52 based on the charge / discharge current and terminal voltage detected by the battery sensor 55. The SOC of the high-voltage battery 52 is a ratio indicating the remaining electrical capacity of the high-voltage battery 52, and is the ratio of the amount of stored energy to the full charge capacity of the high-voltage battery 52.

[0017] Furthermore, a motor control unit CU4, which is an electronic control unit, is connected to the inverter 50 that performs the power supply control of the motor generator 15. The motor control unit CU4 controls the motor torque output from the motor generator 15 by controlling the inverter 50, which consists of multiple switching elements, etc. Note that the motor torque of the motor generator 15 includes a power torque generated on the acceleration side when the motor generator 15 is controlled to a power state, and a power generation torque generated on the deceleration side when the motor generator 15 is controlled to a power generation state.

[0018] [Control System] As shown in Figure 2, the vehicle control device 10 is equipped with a control system 60 consisting of multiple electronic control units to control the powertrain 14. The electronic control units constituting the control system 60 include the engine control unit CU1, the transmission control unit CU2, the battery control unit CU3, and the motor control unit CU4, as mentioned above. In addition, the vehicle control unit CU5, which outputs control signals to each of the control units CU1 to CU4, is also a component of the control system 60. These control units CU1 to CU5 are connected to each other so as to be able to communicate via an in-vehicle network 61 such as CAN (Controller Area Network). The vehicle control unit CU5 sets the operating target of the powertrain 14 based on input information from the various control units CU1 to CU4 and various sensors described later. It then generates control signals according to the operating target of the powertrain 14 and outputs these control signals to the various control units CU1 to CU4.

[0019] The vehicle control unit CU5 is connected to a vehicle speed sensor 62 that detects the vehicle speed, which is the driving speed of the hybrid vehicle 11; an accelerator sensor 63 that detects the accelerator opening, which is the amount of accelerator pedal operation; and a brake sensor 64 that detects the amount of brake pedal operation. The vehicle control unit CU5 is also connected to a start switch 65 that is operated by the driver when starting the control system 60.

[0020] Figure 3 shows an example of the basic structure of each control unit CU1 to CU5. As shown in Figure 3, each control unit CU1 to CU5 has a microcontroller 72 into which a processor 70 and main memory (memory) 71 are incorporated. A predetermined program is stored in the main memory 71, and the program is executed by the processor 70. The processor 70 and the main memory 71 are connected to each other so as to be able to communicate with each other. In the example shown, the microcontroller 72 incorporates one processor 70 and one main memory 71, but this is not limited to this, and the microcontroller 72 may incorporate multiple processors 70 and multiple main memory 71.

[0021] Furthermore, each control unit CU1 to CU5 is equipped with an input circuit 73, a drive circuit 74, a communication circuit 75, and an external memory 76, etc. The input circuit 73 converts signals input from various sensors into signals that can be input to the microcontroller 72. The drive circuit 74 generates drive signals for actuators such as the valve unit 45 mentioned above, based on signals output from the microcontroller 72. The communication circuit 75 converts signals output from the microcontroller 72 into communication signals for other control units. The communication circuit 75 also converts communication signals received from other control units into signals that can be input to the microcontroller 72. In addition, programs and various data are stored in the external memory 76, such as a non-volatile memory.

[0022] [Driving Mode] Figure 4 shows the operation status of EV mode, and Figure 5 shows the operation status of HEV mode. The hybrid vehicle 11 has two driving modes: EV (Electric Vehicle) mode and HEV (Hybrid Electric Vehicle) mode. As will be described later, the EV mode, which is the motor mode, is a driving mode in which the motor generator 15 is driven by releasing the forward clutch 25, and the HEV mode, which is the engine mode, is a driving mode in which the engine 12 is driven by engaging the forward clutch 25.

[0023] As shown in Figure 4, when EV mode is selected as the driving mode, the forward clutch 25 is controlled to be released, the engine 12 is controlled to be stopped, and the motor generator 15 is controlled to be in a powered state. As a result, as indicated by the white arrows in Figure 4, motor torque can be transmitted to the rear wheels 19r, and the hybrid vehicle 11 can be driven using the motor generator 15. In EV mode, when the hybrid vehicle 11 is decelerated, the motor generator 15 is controlled to be in a regenerative state, that is, a power generation state.

[0024] As shown in Figure 5, when the HEV mode is selected as the driving mode, the forward clutch 25 is controlled to be engaged, the engine 12 is controlled to be running, and the motor generator 15 is controlled to be powered. As a result, as indicated by the white arrows in Figure 5, engine torque and motor torque can be transmitted to the rear wheels 19r, and the hybrid vehicle 11 can be driven using the engine 12 and motor generator 15.

[0025] In the example shown in Figure 5, the motor generator 15 is controlled to be in a powering state in HEV mode, but this is not the only option; the motor generator 15 may also be controlled to be in an idle state or a regenerative state. In other words, if the SOC of the high-voltage battery 52 decreases, the power supplied to the motor generator 15 becomes insufficient, so the motor generator 15 is controlled to be in an idle state or a power generation state. It goes without saying that even when the motor generator 15 is in a powering state in HEV mode, when the hybrid vehicle 11 is decelerating, the motor generator 15 is controlled to be in a regenerative state, i.e., a power generation state.

[0026] Figure 6 is a driving mode map showing an example of the operating regions for EV mode and HEV mode. As shown in Figure 6, the driving mode map has a boundary line L1 that demarcates the operating regions for EV mode and HEV mode. The required driving force shown in Figure 6 is the driving force requested by the control system 60 to the powertrain 14. The control system 60 can set the required driving force based, for example, on the accelerator pedal position, which is the accelerator pedal operation amount. In other words, the more the accelerator pedal position increases as the accelerator pedal is pressed, the greater the required driving force for the hybrid vehicle 11 is set to be, and the more the accelerator pedal position decreases as the accelerator pedal is released, the smaller the required driving force for the hybrid vehicle 11 is set to be.

[0027] As shown by arrow A in Figure 6, when the HEV mode is running, if the required driving force decreases or the vehicle speed decreases so that it falls below the boundary line L1, the control system 60 switches the driving mode from HEV mode to EV mode. On the other hand, as shown by arrow B in Figure 6, if the required driving force increases or the vehicle speed increases so that it exceeds the boundary line L1, the control system 60 switches the driving mode from EV mode to HEV mode. In this specification, the required driving force is the driving force set based on the accelerator opening from the viewpoint of determining the driving mode, and the target driving force, which will be described later, is the driving force used to control the motor generator 15 and the engine 12.

[0028] [Driving Mode Switching Control (Flowchart)] Next, we will explain the driving mode switching control that switches the driving mode from EV mode to HEV mode. Figures 7 and 8 are flowcharts showing an example of the execution procedure for driving mode switching control. In the flowcharts of Figures 7 and 8, the points marked with the symbol A are connected to each other. Figure 9 is a diagram showing an example of the relationship between delay time Td and accelerator opening, and Figure 10 is a diagram showing an example of the relationship between driving force change speed Sdf and accelerator opening. Note that each step shown in the flowcharts of Figures 7 and 8 is a process executed by the processor 70 that constitutes the control system 60. Furthermore, the driving mode switching control shown in Figures 7 and 8 is a control that is executed at predetermined intervals by the control system 60 after the driver operates the start switch 65 and the control system 60, consisting of the vehicle control unit CU5, etc., is started.

[0029] As shown in Figure 7, in step S10, it is determined whether or not the vehicle is in EV mode. If it is determined in step S10 that the vehicle is in HEV mode, the process proceeds to step S11, where the vehicle speed and required driving force are updated. As mentioned above, the required driving force increases as the accelerator pedal opening increases, and decreases as the accelerator pedal opening decreases. In the following step S12, it is determined whether or not to switch the driving mode from EV mode to HEV mode based on the vehicle speed and required driving force. For example, as shown by arrow C in Figure 6, if the required driving force increases from the first driving force Df1 to the second driving force Df2 by pressing the accelerator pedal (accelerator operation) in EV mode, exceeding the boundary line L1, a switch from EV mode to HEV mode is determined. In other words, pressing the accelerator pedal in EV mode determines a switch from EV mode, where the target driving force is set to the first driving force Df1, to HEV mode, where the target driving force is set to the second driving force Df2.

[0030] In this way, once the decision to switch from EV mode to HEV mode is made, the system proceeds to step S13, where the transition driving force Dfa used in the driving mode switching process is set. This transition driving force Dfa is greater than the first driving force Df1, which is the target driving force in EV mode, and less than the second driving force Df2, which is the target driving force in HEV mode. In step S14, the delay time Td used in the driving mode switching process is set based on the accelerator opening, and in step S15, the driving force change rate Sdf used in the driving mode switching process is set based on the accelerator opening. Here, as shown in Figure 9, the larger the accelerator opening, the shorter the delay time Td is set to. Also, as shown in Figure 10, the larger the accelerator opening, the faster the driving force change rate Sdf is set to. In other words, the driving force change rate Sdf is set to increase as the accelerator opening increases.

[0031] As shown in Figure 8, in step S16, the motor generator 15 is controlled based on the transition driving force Dfa, and in the following step S17, the engine 12 is started using a starter motor (not shown) and the forward clutch 25 is switched to the engaged state. Next, in step S18, it is determined whether or not the engine start is complete. If it is determined in step S18 that the engine start is complete, the process proceeds to step S19, where it is determined whether or not the forward clutch 25 has been fully engaged. If it is determined in step S19 that the forward clutch 25 has been fully engaged, the process proceeds to step S20, where it is determined whether or not the delay time Td has elapsed. The determination of whether or not the engine start is complete is based, for example, on whether or not the engine speed exceeds a predetermined speed. The determination of whether or not the forward clutch 25 has been fully engaged is based, for example, on whether or not the speed difference between the turbine speed and the primary speed falls below a predetermined value.

[0032] In step S20, if it is determined that the delay time Td has elapsed, the process proceeds to step S21, where the motor generator 15 and engine 12 are controlled based on the target driving force, which is the second driving force Df2, and the driving force change rate Sdf. In other words, in step S21, the control system 60 gradually increases the target driving force from the transition driving force Dfa to the second driving force Df2 according to the driving force change rate Sdf. Then, the control system 60 controls the motor generator 15 and engine 12 based on the target driving force increasing toward the second driving force Df2. This allows for precise control of the torque transmitted from the engine 12 to the primary pulley 20 via the torque converter 26, and enables appropriate switching of the driving mode from EV mode to HEV mode.

[0033] [Driving mode switching control (timing chart)] Next, the aforementioned driving mode switching control will be explained using a timing chart. Figure 11 is a timing chart showing the execution status of the driving mode switching control, and Figure 12 is a timing chart showing an enlarged portion of the timing chart shown in Figure 11. In Figures 11 and 12, "Ne" is the engine speed, "Nt" is the turbine speed, and "Np" is the primary speed. Also, "Tqt" is the turbine torque output from the turbine shaft 32, "Tqm" is the motor torque output from the motor generator 15, and "Tqp" is the primary torque output from the primary shaft 24. The primary torque Tqp is the sum of the turbine torque Tqt and the motor torque Tqm.

[0034] As shown in Figure 11 at time t1, when the accelerator pedal is pressed during EV mode and the required driving force increases above the boundary line L1 (symbol a1), a switch from EV mode to HEV mode is decided (symbol b1). When a switch from EV mode to HEV mode is decided (symbol b1), the target driving force is increased from the first driving force Df1 to the transition driving force Dfa (symbol c1), and the motor torque Tqm is controlled toward the target torque Tqa corresponding to the transition driving force Dfa (symbol d1). In other words, since the motor torque Tqm is controlled toward the target torque Tqa, the primary torque Tqp is increased toward the target torque Tqa (symbol d1). Furthermore, when a switch from EV mode to HEV mode is decided (symbol b1), the engine 12 is started and controlled to the driving state (symbol e1), and the forward clutch 25 is controlled to the engaged state (symbol f1). Thus, once a switch from EV mode to HEV mode is decided, the control system 60 controls the motor generator 15 based on a transition drive force Dfa that is greater than the first drive force Df1, while starting the engine 12 and engaging the forward clutch 25.

[0035] As shown in Figure 11 at times t2 and t3, control of the motor generator 15 based on the transition drive force Dfa continues from the completion of engine start and forward clutch engagement until a delay time Td has elapsed. Then, as shown at time t3, once the delay time Td has elapsed from the completion of engine start and forward clutch engagement, the target drive force is increased from the transition drive force Dfa towards the second drive force Df2 (symbol c2), and the primary torque Tqp is controlled towards the target torque Tq2 corresponding to the second drive force Df2 (symbol d2). This completes the switch from EV mode to HEV mode. In the illustrated example, the primary torque Tqp is increased towards the target torque Tq2 (symbol d2) by increasing the turbine torque Tqt (symbol d3) while decreasing the motor torque Tqm (symbol d4).

[0036] Subsequently, as shown at time t4, the motor torque Tqm is controlled to the power generation side, i.e., the deceleration side, to counteract the increase in turbine torque Tqt due to the engine 12 revving up (symbol d5). This allows the primary torque Tqp to be maintained at the target torque Tq2 even when the turbine torque Tqt increases significantly. In the illustrated example, since the motor generator 15 is allowed to idle in HEV mode, the motor torque Tqm is controlled toward zero (symbol d6), and the turbine torque Tqt is controlled toward the target torque Tq2 (symbol d7).

[0037] As described above, when the driving mode is switched from EV mode to HEV mode, the control system 60 controls the motor generator 15 based on a transition driving force Dfa that is greater than the first driving force Df1, while starting the engine 12 and engaging the forward clutch 25. Furthermore, after a delay time Td has elapsed since the engine 12 was started and the forward clutch 25 was engaged, the control system 60 controls the motor generator 15 and the engine 12 based on a second driving force Df2 that is greater than the transition driving force Dfa. In this way, by waiting for the delay time Td to elapse, the turbine torque Tqt is built up before the target driving force is raised to the second driving force Df2. This allows for precise control of the turbine torque Tqt, enabling the driving mode to be switched without causing any discomfort to the driver.

[0038] Here, as shown in Figure 12 at time t2, it is difficult to accurately control the turbine torque Tqt by increasing or decreasing the engine torque immediately after the engine starts and the forward clutch engages. In other words, slip occurs in the torque converter 26 that transmits the engine torque, so in order to reflect the increase or decrease in engine torque in the turbine torque Tqt, it is necessary to wait for a predetermined time Ta to elapse, as shown at time α. Therefore, the aforementioned delay time Td is set to a time longer than the predetermined time Ta in order to ensure that the turbine torque Tqt has risen up, that is, that the engine torque has been transmitted to the turbine shaft 32. As a result, the target driving force can be increased after the turbine torque Tqt has risen up, thereby improving the accuracy of the engine 12's control of the turbine torque Tqt and enabling the appropriate switching of the driving mode to HEV mode. In other words, the target driving force can be set so as not to exceed the driving force that can be output from the powertrain 14, so the driving force of the powertrain 14 can be controlled without causing discomfort to the driver.

[0039] As mentioned above, the delay time Td is set to be shorter as the accelerator pedal opening increases. This allows the timing of the target driving force build-up, indicated by time t3, to be brought forward when the accelerator pedal is pressed down hard, i.e., when the driver's acceleration request is high, enabling the hybrid vehicle 11 to accelerate quickly. Also, as mentioned above, the driving force change rate Sdf, which is the rate at which the target driving force increases, is increased as the accelerator pedal opening increases. This allows the target driving force to be increased quickly from the transition driving force Dfa to the second driving force Df2 when the accelerator pedal is pressed down hard, enabling the hybrid vehicle 11 to accelerate quickly.

[0040] Next, the responsiveness of the motor-generator 15 will be explained. As mentioned above, control of the motor-generator 15 based on the transition driving force Dfa continues from the time the engine starts and the forward clutch engages until the delay time Td has elapsed. As a result, as shown at time α in Figure 12, the motor torque Tqm can be reduced in a responsive manner in accordance with the increase in turbine torque Tqt (indicated by d3, d4), and excessive fluctuations in the primary torque Tqp can be suppressed. In other words, the primary torque Tqp can be controlled toward the target driving force without causing discomfort to the driver due to excessive torque fluctuations.

[0041] For example, as shown by the symbol g1 in Figure 11, if the target driving force is increased to the second driving force Df2 without waiting for the delay time Td to elapse, depending on the specifications of the motor generator 15, the target torque of the motor generator 15 may exceed the upper limit torque. In this way, if a target torque exceeding the upper limit torque of the motor generator 15 is set, the motor torque Tqm will be insufficient for the target torque, making it impossible to increase the actual driving force to the target driving force, the second driving force Df2. Under these circumstances, the deviation between the target driving force and the actual driving force will accumulate excessively, which may affect the torque control of the motor generator 15. For example, if PID control including integral control is used for motor torque control, the deviation between the target driving force and the actual driving force will accumulate excessively, which will reduce the response speed of the motor generator 15.

[0042] Therefore, in this embodiment, the transition driving force Dfa is set to the driving force obtained when the motor generator 15 is controlled to the powered state at its upper limit torque. In other words, the target torque Tqa corresponding to the transition driving force Dfa is set to the upper limit torque that the motor generator 15 can output. When the decision to switch from EV mode to HEV mode is made, the target driving force is increased from the first driving force Df1 to the transition driving force Dfa. As a result, the motor generator 15 can obtain the transition driving force Dfa, which is the target driving force, so that the deviation between the target driving force and the actual driving force does not accumulate excessively, and the motor torque Tqm can be quickly reduced at the timing indicated by time α in Figure 12. In other words, at the timing indicated by time α, the turbine torque Tqt rises rapidly due to engine starting, but the motor torque Tqm can be reduced in a responsive manner in line with this rise in turbine torque Tqt.

[0043] In other words, as shown by the dashed line β1 in Figure 12, if the target driving force is increased to the second driving force Df2 before the delay time Td has elapsed, the deviation between the target driving force and the actual driving force will accumulate excessively. Therefore, at time t3, as shown by the dashed line β2, the decrease in motor torque Tqm will be delayed, and as shown by the dashed line β3, the primary torque Tqp will increase rapidly. In this case, as shown by the dashed line β4, the vehicle acceleration will increase excessively and a large jerk will occur, which may cause discomfort to the driver when switching driving modes. However, by maintaining the target driving force at the transition driving force Dfa, the excessive increase in primary torque Tqp can be suppressed.

[0044] In the above explanation, the transition driving force Dfa is set to the driving force obtained when the motor generator 15 is controlled to the powered state with the upper limit torque, but it is not limited to this. For example, the transition driving force Dfa may be set to a value less than or equal to the driving force obtained when the motor generator 15 is controlled to the powered state with the upper limit torque. In this way, even when the transition driving force Dfa is set to a small value, the deviation between the target driving force and the actual driving force when switching driving modes can be eliminated, and the motor generator 15 can be controlled appropriately.

[0045] [Other embodiments of the powertrain] The powertrain 14 shown in Figure 2 connects the engine 12 and motor generator 15 to the rear wheel 19r, but is not limited to this configuration. The engine 12 only needs to be connected to at least one of the front wheel 19f or the rear wheel 19r, and the motor generator 15 only needs to be connected to at least one of the front wheel 19f or the rear wheel 19r. Figures 13 and 14 show other examples of powertrain configurations.

[0046] As shown in Figure 13, the engine 12 and the rear wheel 19r are connected via a power transmission path 30, which is composed of a rotating shaft and the like. The power transmission path 30 connecting the engine 12 and the rear wheel 19r is equipped with a torque converter 26 and a forward clutch 25. A motor generator 15 is connected to a secondary shaft 27 that constitutes the power transmission path 30 via a gear train 80. In other words, the motor generator 15 is connected to the rear wheel 19r via the power transmission path 30 from the output side of the continuously variable transmission mechanism 23. A vehicle control device that controls such a powertrain 81 can be made to function in the same way as the vehicle control device 10 described above. In the example shown in Figure 13, the engine 12 and motor generator 15 are connected to the rear wheel 19r, but this is not the only option. For example, the engine 12 and motor generator 15 may be connected to the front wheel 19f, or they may be connected to both the front wheel 19f and the rear wheel 19r.

[0047] As shown in Figure 14, a motor-generator 15 is connected to the rear wheel 19r via a power transmission path 90. The engine 12 is connected to the front wheel 19f via a power transmission path 91, which consists of a rotating shaft and the like. A torque converter 26 and a forward clutch 25 are provided in the power transmission path 91 connecting the engine 12 and the front wheel 19f. Thus, in the illustrated powertrain 92, the engine 12 is connected to the front wheel 19f, while the motor-generator 15 is connected to the rear wheel 19r. A vehicle control device that controls such a powertrain 92 can function in the same way as the vehicle control device 10 described above. Note that a configuration in which the engine 12 is connected to the rear wheel 19r and the motor-generator 15 is connected to the front wheel 19f is also possible.

[0048] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention. In the above description, the control system 60 is composed of a plurality of control units CU1 to CU5, but it is not limited to this. For example, the control system 60 may be composed of a single control unit. Also, the powertrain 14 shown in the figure is equipped with a continuously variable transmission mechanism 23 consisting of a pair of pulleys 20 and 21, but it is not limited to this. For example, it may be a powertrain equipped with a planetary gear type automatic transmission mechanism, or a powertrain without a transmission mechanism. Also, the forward clutch 25 may be a friction clutch or a meshing clutch. Also, the motor generator 15 may be a so-called in-wheel motor provided on the front wheel 19f or the rear wheel 19r.

[0049] In the example shown in Figure 9, the delay time Td is continuously changed according to the accelerator opening, but this is not the only way; the delay time Td may be changed in steps according to the accelerator opening. Also, in the above explanation, the delay time Td is changed based on the accelerator opening, but this is not the only way; a preset fixed value for the delay time Td may be used. In the example shown in Figure 10, the driving force change rate Sdf is continuously changed according to the accelerator opening, but this is not the only way; the driving force change rate Sdf may be changed in steps according to the accelerator opening. Also, in the above explanation, the driving force change rate Sdf is changed based on the accelerator opening, but this is not the only way; a preset fixed value for the driving force change rate Sdf may be used.

[0050] In the example shown in Figure 12, the motor torque Tqm is reduced at time α, but this is not limited to this. Depending on the magnitude of the target driving force, the motor torque Tqm may be maintained or increased. Also, in the example shown in Figure 11, when switching from EV mode to HEV mode, the forward clutch 25 is engaged after the engine 12 starts to start, but this is not limited to this. The engine 12 may start after the forward clutch 25 is engaged, or the engagement of the forward clutch 25 and the start of the engine 12 may start simultaneously. Also, in the example shown in Figure 11, the forward clutch 25 is engaged after the engine 12 has started, but this is not limited to this. The engine 12 may start after the forward clutch 25 is engaged, or the engine 12 may start and the engagement of the forward clutch 25 may be completed simultaneously. Furthermore, in the illustrated example, the motor generator 15 is directly connected to the primary shaft 24, but this is not limited to this. The motor generator 15 may be connected to the primary shaft 24 via a clutch mechanism. This allows the clutch mechanism to be released and the rotation of the motor generator 15 to stop if the State of Charge (SOC) of the high-voltage battery 52 decreases in HEV mode. [Explanation of Symbols]

[0051] 10 Vehicle control devices 11 Hybrid Vehicles 12 Engines 15. Motor Generator (Electric Motor) 19r Rear wheel (first wheel) 19f Front wheel (2nd wheel) 25. Forward clutch (clutch mechanism) 26 Torque Converter 30 Power transmission path 60 Control Systems 70 processors 71 Main memory (memory) 91 Power transmission path Df1 First drive force Df2 Second drive force Dfa transition drive force Td Delay time Sdf: Driving force change rate (increase rate)

Claims

1. A vehicle control device installed in a hybrid vehicle, An electric motor connected to at least one of the first wheel and the second wheel, An engine connected to at least one of the first wheel and the second wheel via a power transmission path, A clutch mechanism provided in the power transmission path, A torque converter is provided in the power transmission path, A control system comprising a processor and memory connected to each other in a manner that enables communication, for controlling the electric motor, the engine and the clutch mechanism, It has, The driving modes of the aforementioned hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. The control system is When the required driving force increases from the first driving force to the second driving force due to accelerator operation, and the driving mode is switched from the motor mode to the engine mode, While controlling the electric motor based on a transitional driving force greater than the first driving force, the engine is started and the clutch mechanism is engaged. After the engine has started and the clutch mechanism has engaged, and a delay time has elapsed, the electric motor and the engine are controlled based on a second driving force that is greater than the transition driving force. The control system sets the delay time to be shorter as the amount of accelerator operation increases. Vehicle control device.

2. A vehicle control device installed in a hybrid vehicle, An electric motor connected to at least one of the first wheel and the second wheel, An engine connected to at least one of the first wheel and the second wheel via a power transmission path, A clutch mechanism provided in the power transmission path, A torque converter is provided in the power transmission path, A control system comprising a processor and memory connected to each other in a manner that enables communication, for controlling the electric motor, the engine and the clutch mechanism, It has, The driving modes of the aforementioned hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. The control system is When the required driving force increases from the first driving force to the second driving force due to accelerator operation, and the driving mode is switched from the motor mode to the engine mode, While controlling the electric motor based on a transitional driving force greater than the first driving force, the engine is started and the clutch mechanism is engaged. After the engine has started and the clutch mechanism has engaged, and a delay time has elapsed, the electric motor and the engine are controlled based on a second driving force that is greater than the transition driving force. The aforementioned transition driving force is the driving force obtained when the electric motor is controlled to the powered state with the upper limit torque. Vehicle control device.

3. A vehicle control device installed in a hybrid vehicle, An electric motor connected to at least one of the first wheel and the second wheel, An engine connected to at least one of the first wheel and the second wheel via a power transmission path, A clutch mechanism provided in the power transmission path, A torque converter is provided in the power transmission path, A control system comprising a processor and memory connected to each other in a manner that enables communication, for controlling the electric motor, the engine and the clutch mechanism, It has, The driving modes of the aforementioned hybrid vehicle include a motor mode in which the clutch mechanism is released and the electric motor is driven, and an engine mode in which the clutch mechanism is engaged and the engine is driven. The control system is When the required driving force increases from the first driving force to the second driving force due to accelerator operation, and the driving mode is switched from the motor mode to the engine mode, While controlling the electric motor based on a transitional driving force greater than the first driving force, the engine is started and the clutch mechanism is engaged. After the engine has started and the clutch mechanism has engaged, and a delay time has elapsed, the electric motor and the engine are controlled based on a second driving force that is greater than the transition driving force. The control system is After the engine has started and the clutch mechanism has engaged, and after the delay time has elapsed, the electric motor and the engine are controlled based on a driving force that gradually increases from the transitional driving force to the second driving force. The greater the accelerator pedal input, the faster the rate at which the driving force increases from the transitional driving force to the second driving force is increased. Vehicle control device.

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