vehicle

Abstract

A vehicle (10) is provided with: an engine (ENG); a second motor generator (MG2) mechanically connected to the engine (ENG); a first motor generator (MG1) mechanically connected to a driving wheel (DW); a battery (BAT) capable of outputting electric power used for driving the first motor generator (MG1); and a control device (20). The control device (20) comprises a virtual stepped gear shift mode, and the virtual stepped gear shift mode comprises a series travel mode and an EV travel mode. When the control device (20) has switched to the virtual stepped gear shift mode, the control device (20) operates in the series travel mode, and restricts a transition from the series travel mode to the EV travel mode on the basis of gear shift position related information relating to a gear shift position.

Description

Vehicle

[0001] The present invention relates to a vehicle.

[0002] Conventionally, a so-called series hybrid vehicle that can perform series running, in which drive wheels are driven by a motor and a generator is driven by an engine to run, is known. In series running, since the engine speed is controlled regardless of the user's intention, for a user accustomed to an engine-driven vehicle, the control of the engine speed may feel uncomfortable. As a means for suppressing such discomfort, for example, in Patent Document 1, a target engine speed simulating a transmission is determined based on an accelerator operation amount indicating the user's intention of acceleration and deceleration, and a generator is driven based on the determined target engine speed. A series hybrid vehicle is described.

[0003] Further, in Patent Document 2, by connecting an engine to an electric motor via a clutch, switching from an EV mode to a HEV mode is performed. After the electric motor starts the internal combustion engine via the clutch, the clutch is maintained in a engaged state for a predetermined time, and fuel cut within the predetermined time is prohibited. It is described.

[0004] Japanese Patent Application Laid-Open No. 2010-173389, Japanese Patent No. 5786965

[0005] However, as described in Patent Document 2, it is not always appropriate to prohibit switching of the running mode again for a certain period of time after switching of the running mode. That is, if the time for prohibiting switching of the running mode is short, switching of the running mode cannot be avoided in a short period, while if the time for prohibiting switching of the running mode is long, a situation may occur where the change in the running situation during that period cannot be responded to.

[0006] The present invention provides a vehicle capable of suppressing the occurrence of switching of the running mode in a short period while responding to changes in the running state.

[0007] The present invention relates to a vehicle comprising: an engine; a second electric motor mechanically connected to the engine; a first electric motor mechanically connected to a drive wheel; a battery capable of outputting power used to drive the first electric motor; and a control device capable of controlling the engine, the battery, the first electric motor, and the second electric motor, wherein the control device has a virtual stepped gear mode that controls the engine speed during movement by the braking force of the first electric motor to a speed determined by a preset virtual gear line and vehicle speed according to the gear stage, and / or controls the driving force of the first electric motor during movement by the braking force of the first electric motor based on a preset drive force line and vehicle speed according to the gear stage, and the virtual stepped gear mode comprises: a first driving mode in which the engine is operated at the speed and power generated by the second electric motor is supplied to the first electric motor, and power is output from the first electric motor to the drive wheel; and a second driving mode in which the engine is stopped and power from the battery is supplied to the first electric motor, and power is output from the first electric motor to the drive wheel. When the control device switches to the virtual stepped gear mode, it performs the first driving mode and restricts the transition from the first driving mode to the second driving mode based on gear-related information associated with the gears.

[0008] According to the present invention, it is possible to suppress the occurrence of switching driving modes in a short period of time while responding to changes in driving conditions.

[0009] Figure 1 is a diagram showing the schematic configuration of the vehicle 10 of this embodiment. Figure 2 is a block diagram showing an example of the control device 20. Figure 3 is a diagram showing an example of a shift map when downshifting while driving in normal mode. Figure 4 is a diagram showing an example of a shift map when upshifting while driving in normal mode. Figure 5 is a diagram showing an example of a Ne search map that determines the engine speed Ne when performing simulated gear shift control in normal mode. Figure 6 is a diagram showing a simulated gear shift map used for gear shifting when a gear shift request operation is made with the accelerator pedal OFF. Figure 7 is an enlarged view of the normal gear shift map used for gear shifting when a gear shift request operation is made with the accelerator pedal ON. Figure 8 is a timing chart of gear shift simulation control when a gear shift request operation is made while the vehicle 10 is driving and the accelerator pedal is OFF. Figure 9 is a timing chart of gear shift simulation control when a gear shift request operation is made while the vehicle 10 is driving and the accelerator pedal is ON. Figure 10 is a timing chart when a downshift request is made while gear shift simulation control is being executed. Figure 11 is a timing chart of the switching effect control when a switching request operation is made while the vehicle 10 is stopped (accelerator pedal OFF). Figure 12 is a diagram showing an example of the torque characteristics of the first motor generator MG1. Figure 13 is a diagram showing another example of the torque characteristics of the first motor generator MG1.

[0010] Hereinafter, one embodiment of the vehicle control device of the present invention will be described in detail with reference to the drawings. Not all of the features described in the following embodiment are necessarily essential to the present invention. Furthermore, two or more of the features described in the following embodiment may be arbitrarily combined. In the following, identical or similar elements will be denoted by the same or similar reference numerals, and their descriptions may be omitted or simplified as appropriate.

[0011] [Vehicle] First, a vehicle equipped with a control device (control device 20, described later) which is one embodiment of the vehicle control device of the present invention will be described.

[0012] As shown in Figure 1, the vehicle 10 of this embodiment is a hybrid electric vehicle and is composed of an engine ENG, a first motor generator MG1, a second motor generator MG2, a battery BAT, a clutch CL, a power converter 11, various sensors, and a control device 20. In Figure 1, thick solid lines indicate mechanical connections, double dotted lines indicate electrical wiring, and thin solid arrows indicate the transmission and reception of control signals or detection signals.

[0013] The engine ENG is an internal combustion engine, such as a gasoline engine or a diesel engine, which outputs power generated by burning the supplied fuel. The engine ENG is connected to the second motor generator MG2 and also to the drive wheels DW of the vehicle 10 via the clutch CL. The power output by the engine ENG (hereinafter also referred to as "engine ENG output") is transmitted to the second motor generator MG2 when the clutch CL is disengaged, and to the second motor generator MG2 and the drive wheels DW when the clutch CL is engaged (closed). The second motor generator MG2 and the clutch CL will be described later.

[0014] The first motor generator MG1 is a motor generator (a so-called "traction motor") mainly used as a drive source for the vehicle 10, and is composed of, for example, an AC motor. The first motor generator MG1 is electrically connected to the battery BAT and the second motor generator MG2 via the power converter 11. Power can be supplied to the first motor generator MG1 from at least one of the battery BAT and the second motor generator MG2. When power is supplied to the first motor generator MG1, it operates as an electric motor and outputs power for the vehicle 10 to move. The first motor generator MG1 is also connected to the drive wheels DW, and the power output by the first motor generator MG1 (hereinafter also referred to as "output of the first motor generator MG1") is transmitted to the drive wheels DW. The vehicle 10 moves when at least one of the output of the engine ENG and the output of the first motor generator MG1 is transmitted to the drive wheels DW.

[0015] Furthermore, the first motor generator MG1 can also perform regenerative operation as a generator when the vehicle 10 is braking, generating electricity (so-called regenerative power generation). The power generated by the regenerative operation of the first motor generator MG1 (hereinafter also referred to as "regenerative power") is supplied to the battery BAT, for example, via the power converter 11. This allows the battery BAT to be charged by the regenerative power.

[0016] Furthermore, regenerative power may not be supplied to the battery BAT, but instead to the second motor generator MG2 via the power converter 11. By supplying regenerative power to the second motor generator MG2, "waste power" can be consumed without charging the battery BAT. During waste power consumption, the regenerative power supplied to the second motor generator MG2 is used to drive the second motor generator MG2, and the power generated is input to the engine ENG, where it is consumed by mechanical friction losses, etc.

[0017] The second motor generator MG2 is a motor generator primarily used as a generator, and is composed of, for example, an AC motor. The second motor generator MG2 is driven by the power of the engine ENG and generates electricity. The electricity generated by the second motor generator MG2 is supplied to at least one of the battery BAT and the first motor generator MG1 via the power converter 11. By supplying the electricity generated by the second motor generator MG2 to the battery BAT, the battery BAT can be charged with that electricity. Also, by supplying the electricity generated by the second motor generator MG2 to the first motor generator MG1, the first motor generator MG1 can be driven with that electricity.

[0018] Furthermore, the second motor generator MG2 can also function as a starter motor to start the engine. That is, for example, when transitioning from EV driving mode to series driving mode as described later, power from the battery BAT is supplied to the second motor generator MG2, and the second motor generator MG2, driven by that power, cranks the engine, thereby starting the engine.

[0019] The power converter 11 is a device (a so-called power control unit, also called a "PCU") that converts the input power and outputs the converted power, and is connected to the first motor generator MG1, the second motor generator MG2, and the battery BAT. For example, the power converter 11 is composed of a first inverter 111, a second inverter 112, and a voltage control device 110. The first inverter 111, the second inverter 112, and the voltage control device 110 are electrically connected to each other.

[0020] The voltage control device 110 converts the input voltage and outputs the converted voltage. A DC / DC converter or the like can be used as the voltage control device 110. For example, when supplying power from the battery BAT to the first motor generator MG1, the voltage control device 110 boosts the output voltage of the battery BAT and outputs it to the first inverter 111. Also, for example, when regenerative power generation is performed by the first motor generator MG1, the voltage control device 110 steps down the output voltage of the first motor generator MG1, which is received via the first inverter 111, and outputs it to the battery BAT. Also, when power generation is performed by the second motor generator MG2, the voltage control device 110 steps down the output voltage of the second motor generator MG2, which is received via the second inverter 112, and outputs it to the battery BAT.

[0021] When the first inverter 111 supplies power from the battery BAT to the first motor generator MG1, it converts the power (DC) from the battery BAT received via the voltage control device 110 into AC and outputs it to the first motor generator MG1. Also, when regenerative power generation is performed by the first motor generator MG1, the first inverter 111 converts the power (AC) received from the first motor generator MG1 into DC and outputs it to the voltage control device 110. Furthermore, when the first inverter 111 decommissions the regenerative power from the first motor generator MG1, it converts the power (AC) received from the first motor generator MG1 into DC and outputs it to the second inverter 112.

[0022] When power is generated by the second motor generator MG2, the second inverter 112 converts the power (AC) received from the second motor generator MG2 into DC and outputs it to the voltage control device 110. Also, when the regenerative power of the first motor generator MG1 is to be discarded, the second inverter 112 converts the regenerative power (DC) received from the first motor generator MG1 via the first inverter 111 into AC and outputs it to the second motor generator MG2.

[0023] A battery (BAT) is a rechargeable secondary battery having multiple energy storage cells connected in series or in series-parallel. A battery (BAT) is configured to output high voltages, such as 100 to 400 [V]. Lithium-ion batteries and nickel-metal hydride batteries can be used as the energy storage cells in a battery (BAT).

[0024] The clutch CL can be in a connected state, which connects (closes) the power transmission path from the engine ENG to the drive wheel DW, and a disconnected state, which disconnects (interrupts) the power transmission path from the engine ENG to the drive wheel DW. The output of the engine ENG is transmitted to the drive wheel DW when the clutch CL is in the connected state, and not transmitted to the drive wheel DW when the clutch CL is in the disconnected state.

[0025] The control device 20 is a device (computer) that provides overall control for the entire vehicle 10. For example, it is implemented by an ECU (Electronic Control Unit) that includes a processor 21 for performing various calculations, a memory 22 for storing various information, and an I / F 23 (I / F: Interface) 23 for controlling the input and output of data between the inside and outside of the control device 20. The control device 20 may be implemented by one ECU or by multiple ECUs.

[0026] The control device 20 is provided to communicate with the engine ENG, clutch CL, power converter 11, and various sensors. The control device 20 controls the output of the engine ENG, controls the output of the first motor generator MG1 and the second motor generator MG2 by controlling the power converter 11, and controls the state of the clutch CL, through the execution of a program stored in the memory 22 by the processor 21. As a result, the control device 20 can control the driving mode of the vehicle 10, as will be described later.

[0027] [Driving Modes] Here, we will explain the driving modes that the vehicle 10 can take. The vehicle 10 can take three driving modes: EV driving mode, series driving mode, and engine driving mode. The vehicle 10 will then drive in one of these driving modes. The control device 20 controls which driving mode the vehicle 10 will be driven in.

[0028] [EV Driving Mode] The EV driving mode is an example of the first driving mode in the present invention, in which only the power from the battery BAT is supplied to the first motor generator MG1, and the vehicle 10 is driven by the power output by the first motor generator MG1 according to that power. The EV driving mode is a driving mode in which the vehicle is driven by driving the drive wheels DW only with the first motor generator MG1 of the engine ENG and the first motor generator MG1.

[0029] To explain in more detail, in EV driving mode, the control device 20 disengages the clutch CL. Also in EV driving mode, the control device 20 stops the supply of fuel to the engine ENG and stops the output of power from the engine ENG (hereinafter also referred to as "engine ENG operation"). Therefore, in EV driving mode, power generation by the second motor generator MG2 does not occur. In EV driving mode, the control device 20 supplies only the power from the battery BAT to the first motor generator MG1, and the first motor generator MG1 outputs power corresponding to that power, and the vehicle 10 is driven by that power.

[0030] The control device 20 basically drives the vehicle 10 in EV driving mode on the condition that the power required by the vehicle 10 (hereinafter also referred to as "vehicle-required power") is below a predetermined threshold (hereinafter also referred to as "EV-permitted power"). The vehicle-required power in EV driving mode includes the power required to drive the vehicle 10 by the first motor generator MG1, and changes according to the required driving force and vehicle speed.

[0031] [Series Driving Mode] The series driving mode is an example of the second driving mode in the present invention, in which at least the power generated by the second motor generator MG2 is supplied to the first motor generator MG1, and the vehicle 10 is driven mainly by the power output by the first motor generator MG1 in accordance with that power. The series driving mode is a driving mode in which the drive wheels DW are driven by only the first motor generator MG1 of the engine ENG and the first motor generator MG1.

[0032] To explain in more detail, in series driving mode, the control device 20 disengages the clutch CL. Also in series driving mode, the control device 20 supplies fuel to the engine ENG, causing the engine ENG to output power, and the power from the engine ENG drives the second motor generator MG2. As a result, in series driving mode, power is generated by the second motor generator MG2. Also in series driving mode, the control device 20 disengages the power transmission path with the clutch CL, supplies the power generated by the second motor generator MG2 to the first motor generator MG1, causes the first motor generator MG1 to output power corresponding to that power, and uses that power to drive the vehicle 10.

[0033] The maximum power that can be supplied from the second motor generator MG2 to the first motor generator MG1 is greater than the maximum power that can be supplied from the battery BAT to the first motor generator MG1. Therefore, in series driving mode, the output of the first motor generator MG1 can be increased compared to EV driving mode, and a greater driving force can be obtained.

[0034] In series driving mode, the control device 20 may also supply power from the battery BAT to the first motor generator MG1 as needed. That is, in series driving mode, the control device 20 may supply power from both the second motor generator MG2 and the battery BAT to the first motor generator MG1. This allows for a greater amount of power to be supplied to the first motor generator MG1 compared to the case where only power from the second motor generator MG2 is supplied to the first motor generator MG1, thereby obtaining an even greater driving force.

[0035] [Engine Driving Mode] The engine driving mode is a driving mode in which the vehicle 10 is driven primarily by the power output by the engine ENG, and is a driving mode in which the vehicle is driven by at least the mechanical driving force of the engine ENG driving the drive wheels DW.

[0036] To explain in more detail, in engine-driven mode, the control device 20 engages the clutch CL. Also in engine-driven mode, the control device 20 supplies fuel to the engine ENG, causing the engine ENG to output power. In engine-driven mode, since the power transmission path is engaged by the clutch CL, the power from the engine ENG is transmitted to the drive wheels DW, driving the drive wheels DW. In this way, in engine-driven mode, the control device 20 causes the engine ENG to output power, and that power drives the vehicle 10.

[0037] Furthermore, in engine-driven mode, the control device 20 may supply power from the battery BAT to the first motor generator MG1 as needed. This allows the vehicle 10 to be driven using the power output of the first motor generator MG1, which is supplied with power from the battery BAT, in engine-driven mode, resulting in a greater driving force compared to when the vehicle 10 is driven solely by the engine ENG. In addition, this allows the engine ENG output to be suppressed compared to when the vehicle 10 is driven solely by the engine ENG, thereby improving the fuel efficiency of the vehicle 10.

[0038] The control device 20 executes various programs stored in, for example, the memory 22. As mentioned above, the vehicle 10 can be driven in multiple drive modes, and the control device 20 controls which driving mode to use. Also, when the vehicle is driven in series, the engine ENG is controlled with the engine ENG and drive wheels DW disconnected, so the engine speed Ne will not correspond to the accelerator operation, which may cause discomfort to the user. Therefore, in order to reduce such discomfort to the user, the control device 20 executes a predetermined program to control the second motor generator MG2 so that the engine speed Ne is based on a simulated gear shift. A simulated gear shift is a gear shift that simulates a gear shift that is determined based on, for example, the vehicle speed and the accelerator opening when the engine ENG and drive wheels DW are disconnected.

[0039] Vehicle 10 can operate in series driving mode by selecting between a stepped transmission mode, in which the second motor generator MG2 is controlled to achieve an engine speed Ne based on these simulated gear stages, and a continuously variable transmission mode, which is not based on simulated gear stages. Normally, vehicle 10 is in continuously variable transmission mode, and switches from continuously variable transmission mode to stepped transmission mode upon user request. The user's request for switching is, for example, by pressing a dedicated changeover switch.

[0040] Furthermore, when the vehicle 10 is driven in a series driving stepped-speed mode, as described above, the first motor generator MG1 drives the drive wheels DW. Even in this case, however, it is preferable to realize acceleration and deceleration characteristics based on pseudo-gear stages in order to reduce the discomfort to the user caused by fluctuations in engine speed Ne. Figure 12 shows an example of a torque characteristic map of the first motor generator MG1 corresponding to "1st gear" to "8th gear" in the pseudo-gear stages, with the horizontal axis showing vehicle speed and the vertical axis showing driving force. The control device 20 controls the first motor generator MG1 to output a driving force based on the selected pseudo-gear stage by referring to the driving force line of the driving force map for each pseudo-gear stage. Note that the driving force map is not limited to cases where the driving force is a constant value regardless of vehicle speed, as shown in Figure 12, but may also vary according to vehicle speed, for example, as shown in Figure 13. Figure 13 shows another example of a torque characteristic map of the first motor generator MG1 corresponding to "1st gear" through "8th gear" in the simulated gear shifting stages.

[0041] Furthermore, it is preferable that the vehicle 10 can also select a stepped transmission mode when driving in EV mode. While driving in EV mode, the engine ENG is stopped, but by realizing acceleration and deceleration characteristics based on simulated gears, it is possible to suppress the discomfort felt by users who are accustomed to stepped transmissions.

[0042] Furthermore, it is preferable that the vehicle 10 can shift gears in response to user requests such as paddle shifters, and in manual shift mode, simulated gears are set based on the user's shift requests. In contrast to manual shift mode, the mode in which simulated gears are automatically set by the control device 20 is called automatic shift mode. In other words, there are automatic shift mode and manual shift mode in stepped shift mode. In stepped shift mode and continuously variable shift mode, the control device 20 selects one of the following modes depending on the driving conditions: EV driving mode, series driving mode, or engine driving mode.

[0043] As shown in FIG. 2, the control device 20 includes a pseudo-shift control unit 210, an upshift delay control unit 220, and a switching effect control unit 230 as functional units realized by executing a program. In the following, the processes described as being performed by the pseudo-shift control unit 210, the upshift delay control unit 220, and the switching effect control unit 230 are processes realized by the control device 20.

[0044] Detection values from various sensors are input to the control device 20. For example, a detection value from an accelerator position sensor 120 that detects an operation amount (accelerator opening) with respect to the accelerator pedal of the vehicle 10, a vehicle speed sensor 130 that detects the vehicle speed which is the traveling speed of the vehicle 10, an acceleration sensor 140 that detects the acceleration which is the traveling acceleration of the vehicle 10, a brake sensor 150 that detects an operation amount with respect to the brake pedal of the vehicle 10, etc. are input.

[0045] The pseudo-shift control unit 210 determines the engine speed Ne with respect to the vehicle speed based on a pseudo-shift stage set based on the vehicle speed and the accelerator opening. In other words, the pseudo-shift control unit 210 controls the engine speed Ne of the engine ENG to a rotation speed determined by a plurality of second virtual shift lines preset according to the pseudo-shift stage and the vehicle speed.

[0046] For example, the pseudo-shift control unit 210 determines the pseudo-shift stage based on a shift map stored in the memory 22 in advance. FIGS. 3 and 4 are diagrams showing an example of the shift map. FIG. 3 shows an example of the shift map when downshifting while traveling in the normal mode, and FIG. 4 shows an example of the shift map when upshifting while traveling in the normal mode. In these shift maps, the solid line indicates the downshift line (first virtual shift line) or the upshift line (first virtual shift line) in the normal shift control. The pseudo-shift control unit 210 executes an upshift or a downshift according to changes in the vehicle speed and the accelerator opening. FIGS. 3 and 4 may be referred to as the normal shift map in the following description, and the downshift line and the upshift line in FIGS. 3 and 4 may be referred to as the normal shift line.

[0047] A predetermined hysteresis is set for the downshift line in the shift map of FIG. 3 and the upshift line in the shift map of FIG. 4. This is to prevent the user from being bothered by frequent shifting across the shift lines in a short period of time. For example, a hysteresis is provided for the upshift line indicating an upshift from "3rd gear" to "4th gear" and the downshift line indicating a downshift from "4th gear" to "3rd gear". FIGS. 3 and 4 show the shift maps in the normal mode as an example. However, the pseudo shift control unit 210 may switch the gear stage based on the shift map in the sports mode (not shown) when driving in the sports mode, and may switch the gear stage based on the shift map in the comfort mode (not shown) when driving in the comfort mode.

[0048] Based on the pseudo gear stage set in this way, the pseudo shift control unit 210 determines the engine speed Ne with respect to the vehicle speed. For example, the pseudo shift control unit 210 determines the engine speed with respect to the vehicle speed based on the Ne search map stored in advance in the memory 22. FIG. 5 is a diagram showing an example of the Ne search map for determining the engine speed Ne when performing pseudo shift control in the normal mode. In the Ne search map, a plurality of engine speeds Ne (second virtual shift lines) preset according to the vehicle speed and the pseudo gear stage are drawn. FIG. 5 shows the Ne search map in the normal mode as an example. However, the pseudo shift control unit 210 may determine the engine speed with respect to the vehicle speed based on the Ne search map in the sports mode (not shown) when driving in the sports mode, and may determine the engine speed with respect to the vehicle speed based on the Ne search map in the comfort mode (not shown) when driving in the comfort mode.

[0049] Specifically, when the vehicle 10 is in motion, the pseudo-gear control unit 210 refers to the Ne search map in Figure 5 and determines the engine speed Ne for each pseudo-gear stage in relation to the vehicle speed. In other words, an upshift threshold and a downshift threshold for the engine speed Ne are set for each pseudo-gear stage, and the pseudo-gear control unit 210 performs an upshift or downshift when the engine speed Ne exceeds these thresholds. In Figure 5, the solid line shows the engine speed Ne during acceleration, i.e., the engine speed Ne during an upshift, and the dashed line shows the engine speed Ne during deceleration, i.e., the engine speed Ne during a downshift.

[0050] In this simulated gear shift control, which determines the engine speed Ne relative to the vehicle speed based on the simulated gear stage, the simulated gear shift is performed by changing the driving force of the second motor generator MG2, so there is no mechanical switching when changing gears. As a result, gear changes can be made in a short time, and shift hunting, where gear changes occur in rapid succession, can occur. In particular, if an upshift occurs shortly after a downshift, the engine speed increases with the downshift and then decreases with the upshift. The rapid increase and decrease in engine speed can cause discomfort to the user.

[0051] Therefore, in stepped transmission mode, when the upshift delay control unit 220 receives an upshift request after a gear change, it maintains the gear after the gear change for a predetermined period (hereinafter referred to as the delay time), and performs upshift delay control to shift up the gear after the delay time has elapsed. Specifically, the upshift delay control unit 220 starts an upshift delay timer at the timing of a gear change (for example, downshifting), and prohibits changing the target gear (for example, upshifting) until the delay period has elapsed.

[0052] Furthermore, the switching control unit 230 executes switching control to switch from continuously variable transmission mode to stepped transmission mode and to control the gear ratio after the switch, and prohibits the transition from series driving to EV driving while the switching control is in progress. In other words, EV driving is prohibited while the switching control is in progress, and EV driving is permitted when the switching control is completed. The switch from continuously variable transmission mode to stepped transmission mode is triggered by a user's switching request operation, such as pressing the changeover switch.

[0053] When the user requests a switch to change from stepless transmission mode to stepped transmission mode, the switching control unit 230 sets a gear position lower than the gear position set on the normal transmission line of the normal transmission map in Figures 3 and 4. As a result, when the virtual stepped transmission mode is executed, the gear position is set lower than the normal gear position, which increases the engine speed and allows for a performance effect that enhances driving performance.

[0054] More specifically, the gear shift control unit 230 changes the selected gear based on the accelerator pedal opening angle when the user requests a gear shift.

[0055] When a switching request operation is made with the accelerator pedal OFF, the switching performance control unit 230 sets the gear based on a performance shift map in which a performance shift line is set that is set to a lower gear relative to the vehicle speed than the normal shift line of the normal shift map.

[0056] Figure 6 shows the performance shift map used for shifting gears when a shift request operation is made while the accelerator pedal is OFF. In Figure 6, the solid lines correspond to the upshift lines, which are the normal shift lines in the normal shift map of Figure 4, and the thick dashed lines are the performance shift lines used for shift performance control.

[0057] For example, when the accelerator pedal is OFF and the vehicle speed is V1, if there is a request to switch from continuously variable transmission mode to stepped transmission mode, according to the normal transmission map, the vehicle speed V1 is higher than the upshift line from 3rd to 4th gear, so the 4th gear is selected. However, in the performance transmission map used during the switch, the vehicle speed V1 is lower than the performance shift line from 3rd to 4th gear, so 3rd gear is set.

[0058] Furthermore, this gear shift indicator is variable based on gradient information, and if the downhill gradient is greater than a predetermined value D1, the gear shift indicator is set to a higher speed in proportion to the downhill gradient. By selecting a lower gear when the downhill gradient is large, it is possible to suppress any sense of incongruity in the user's driving experience.

[0059] The gear shift control unit 230 determines the gear shift step based on the performance gear shift map, in which the gear shift lines are set to the lower vehicle speed side compared to the normal gear shift map, and then continues to set the gear shift performance step based on the performance gear shift map even after the shift.

[0060] On the other hand, when a switching request operation is made with the accelerator pedal ON, the switching control unit 230 sets the lowest-speed gear among the gears that can be selected at the current vehicle speed in the normal gear map.

[0061] Figure 7 is an enlarged view of the normal gear shift map used when a gear change request is made while the accelerator pedal is ON. In other words, Figure 7 is an enlarged view of Figure 4. In Figure 7, the solid lines are the upshift lines of the normal gear shift map, and the dashed lines are the downshift lines of the normal gear shift map.

[0062] When a gear change request is made with the accelerator pedal ON, the gear change control unit 230 normally sets the gear based on the gear change map. However, if the driving point set by the current vehicle speed and accelerator pedal opening is P12 (accelerator pedal opening A1, vehicle speed V2) at the time of the change, and assuming that the lowest gear among the selectable gears is gear β-1, then setting the gear to gear β-1 according to the normal gear change map would result in an immediate upshift because the accelerator pedal opening is ON. Therefore, if the vehicle speed from the gear β-1 that should be set to the upshift line to the higher gear β is less than a predetermined value, the upshift line is temporarily shifted to a speed lower than the vehicle speed V2. Consequently, when the driving point set by the current vehicle speed and accelerator pedal opening is P12 (accelerator pedal opening A1, vehicle speed V2), the gear change control unit 230 sets the gear to gear β.

[0063] After determining the gear shift position based on the normal gear shift map, the gear shift performance control unit 230 continues to set the gear shift performance position based on the normal gear shift map even after the gear shift.

[0064] The gear switching control unit 230 sets the gear switching gear to the target gear when gear switching control is in progress, i.e., when the gear switching flag is ON. When the vehicle 10 satisfies the conditions for releasing gear switching control, the gear switching flag is turned OFF, and the system transitions from gear switching control to normal gear shift control. Upon transitioning to normal gear shift control, the pseudo-gear shift control unit 210 sets the normal gear to the target gear. Furthermore, upon transitioning from gear switching control to normal gear shift control, the system becomes capable of EV driving.

[0065] From here, we will explain the conditions for deactivating the transition effect control. The transition effect control is deactivated when any one of the following four deactivation conditions is met.

[0066] (First release condition) The first release condition is when the user requests to switch from stepped speed mode to continuously variable speed mode, such as by pressing the changeover switch. This reflects the user's intention, and when the user requests to switch, the switching performance control unit 230 changes the driving mode from stepped speed mode to continuously variable speed mode.

[0067] (Second Release Condition) The second release condition is when the gear change animation release timer has finished and the upshift delay timer has finished. The gear change animation release timer is a timer that starts when the gear change animation control is initiated and is released after a predetermined time has elapsed. The predetermined time may be set to a release threshold according to the engine speed. The upshift delay timer is a timer based on the upshift delay control described above, which starts when a gear change occurs and has a release threshold set according to the engine speed. When the upshift delay timer is not in operation, the second release condition is met when the gear change animation release timer finishes. When the vehicle is stopped or in reverse and no gear changes are made, the stepped gear mode will continue. Therefore, by ending the gear change animation control after a certain amount of time and allowing the transition to EV driving mode, it is possible to suppress the continued use of the engine when the vehicle is stopped, etc.

[0068] Furthermore, if the control device 20 is performing upshift delay control, the termination of the upshift delay timer is also made a condition, so that EV driving occurs after the switching effect release timer has finished, preventing the upshift prohibition from ending immediately and the engine from being driven again by an upshift.

[0069] (Third Release Condition) The third release condition is when the normal gear position becomes equal to or higher than the gear position used for the gear change animation, and the engine speed Ne becomes equal to or higher than the threshold rotation speed. The threshold rotation speed for engine speed Ne is a threshold rotation speed set according to the gear position, for example, the rotation speed of the upshift line (the upper limit rotation speed for that gear position). When the engine speed Ne becomes equal to or higher than the threshold rotation speed, and the normal gear position becomes equal to or higher than the gear position used for the gear change animation, it can be determined that the vehicle is in a state that can be considered equivalent to normal driving.

[0070] (Fourth Release Condition) The fourth release condition is when a downshift request is received and the normal gear position becomes lower than the gear position used for the shifting effect. Because the engine speed Ne increases due to the downshift, performance control to enhance driving performance becomes unnecessary.

[0071] In this way, by setting a first release condition based on the user's will and a second release condition based on the passage of time, as well as a third release condition and a fourth release condition based on gear shift-related information related to the gear shift, the system can respond to changes in the driving state of the vehicle 10.

[0072] The following section explains the control of the switching effects, referring to the timing charts in Figures 8 to 10.

[0073] Figure 8 is a timing chart of the switching performance control when a switching request operation is made while the vehicle 10 is in motion and the accelerator pedal is OFF. At time T11, when the vehicle 10 is in motion and the accelerator pedal is OFF, if a user requests a switch from continuously variable transmission mode to stepped transmission mode, the switching performance control flag changes from OFF to ON. At this time, the switching performance control unit 230 changes the target gear from the normal transmission gear β+1, which is the gear β set by the normal transmission map, to the switching performance gear β, which is the gear β set by the performance transmission map. This switching performance gear β is the transmission β set based on the performance transmission line in Figure 6, and is the initial transmission β. Note that when the switching performance control flag is OFF, the switching performance gear β is set to a system-invalid value, such as α, for control purposes. After changing the switching performance control flag, the switching performance control unit 230 starts the switching performance release timer.

[0074] Subsequently, when the accelerator pedal is pressed and the engine speed Ne increases, and reaches the upshift line on the performance shift map at time T12, the switching performance control unit 230 upshifts the target gear from gear β to gear β+1. Also, the upshift delay control unit 220 starts the upshift delay timer at the timing when the gear is changed.

[0075] Subsequently, as the engine speed Ne increases further, the switching effect release timer reaches its release threshold at time T13, and the upshift delay timer also reaches its release threshold, thus fulfilling the aforementioned second release condition. When the second release condition is fulfilled, the switching effect control flag changes from the ON state to the OFF state. When the switching effect control flag is in the OFF state, the pseudo-shift control unit 210 sets the target gear stage to the normal shift gear stage β+2, which is the shift stage set by the normal shift map, and the switching effect control unit 230 sets the switching effect gear stage to α for control purposes. In addition, the switching effect release timer and the upshift delay timer are reset.

[0076] Subsequently, the simulated gear shift control unit 210 continues in stepped gear shift mode, sets the gear based on the normal gear shift map, and sets one of the following modes depending on the driving conditions: EV driving mode, series driving mode, or engine driving mode.

[0077] Figure 9 is a timing chart of the gear switching performance control when a gear switching request operation is made while the vehicle 10 is in motion and the accelerator pedal is ON. At time T21, when the vehicle 10 is in motion and the accelerator pedal is ON, if a user requests a gear switching operation to switch from continuously variable transmission mode to stepped transmission mode, the gear switching performance control flag changes from OFF to ON. At this time, the gear switching performance control unit 230 sets the target gear to the gear switching performance gear β. This gear switching performance gear β is the lowest gear among the gears that can be selected at the current vehicle speed, as explained in Figure 7, and becomes the initial gear.

[0078] Subsequently, as the accelerator pedal is pressed and the engine speed Ne continues to rise, at time T22, when it reaches the upshift line of the normal shift map, the target gear is upshifted from gear β to gear β+1. Note that when the accelerator pedal is ON, it is assumed that the vehicle 10 is accelerating, so naturally the engine speed Ne will upshift along the upshift line as the vehicle speed increases, and the upshift delay timer is not activated.

[0079] Subsequently, as the engine speed Ne increases further and reaches the upshift line of the normal shift map at time T23, the target gear shift is upshifted from gear β+1 to gear β+2. At this time, the switching effect gear β+2 catches up with the normal shift gear β+2, and the third release condition is met. When the third release condition is met, the switching effect control flag changes from the ON state to the OFF state. When the switching effect control flag is OFF, the pseudo-shift control unit 210 sets the target gear to the normal shift gear β+2, which is the gear shift set by the normal shift map, and the switching effect control unit 230 sets the switching effect gear to α for control purposes. Also, the switching effect release timer is reset.

[0080] Subsequently, the simulated gear shift control unit 210 continues in stepped gear shift mode, controls the gear shift based on the normal gear shift map, and sets one of the following modes depending on the driving conditions: EV driving mode, series driving mode, or engine driving mode.

[0081] In the example shown in Figure 9, the second release condition is met along with the third release condition. However, since the second release condition has already been explained, a detailed explanation will be omitted here.

[0082] Furthermore, even if a switching request operation is made while the vehicle 10 is in motion and the accelerator pedal is OFF, or even if a switching request operation is made while the vehicle 10 is in motion and the accelerator pedal is ON, if a downshift request is made during the switching performance control, the fourth release condition is met if the normal gear position becomes lower than the switching performance gear position.

[0083] Figure 10 is a timing chart for when a downshift request is made while the switching effect control is being executed. At time T21, a request to switch to stepped gear mode is made and the target gear is set to the switching effect gear β. At time T22, the target gear has shifted up from gear β to gear β+1. If a downshift request is made at time T25, and the downshift is 3 steps from the normal gear β+3, the normal gear β will become lower than the switching effect gear β+1, and the fourth release condition will be met. Note that, in terms of control, the normal gear is selected earlier than the switching effect gear. When the fourth release condition is met, the switching effect control flag changes from the ON state to the OFF state. When the gear change effect control flag is turned OFF, the pseudo-gear change control unit 210 sets the target gear to normal gear β, which is the gear set by the normal gear change map, and the gear change effect control unit 230 sets the gear change effect gear to α for control purposes.

[0084] Subsequently, the simulated gear shift control unit 210 continues in stepped gear shift mode, controls the gear shift based on the normal gear shift map, and sets one of the following modes depending on the driving conditions: EV driving mode, series driving mode, or engine driving mode.

[0085] Figure 11 is a timing chart of the gear change animation control when a gear change request operation is made while the vehicle 10 is stopped (vehicle speed 0 and accelerator pedal OFF). At time T31, when the vehicle 10 is stopped, if the user requests a gear change from continuously variable transmission mode to stepped transmission mode, the gear change animation control flag changes from OFF to ON. At this time, the gear change animation control unit 230 sets the target gear stage to gear change animation gear stage β. After changing the gear change animation control flag, the gear change animation release timer is started. Note that the upshift delay timer is not in operation while the vehicle 10 is stopped because gear changes are not expected.

[0086] When the gear switching control flag changes from the OFF state to the ON state, the engine ENG is activated. While the vehicle 10 is stopped, the engine ENG rotates at idle speed (Figure 5). Subsequently, at time T32, the gear switching release timer reaches the release threshold, and the second release condition described above is met. When the second release condition is met, the gear switching control flag changes from the ON state to the OFF state. When the gear switching control flag is in the OFF state, the pseudo-shift control unit 210 sets the target gear to the normal shift gear β, which is the gear set by the normal shift map, and the gear switching control unit 230 controls the gear switching gear to α. The gear switching release timer is also reset.

[0087] Subsequently, the control device 20 stops the engine ENG. If the accelerator pedal is pressed while the vehicle 10 is stopped and the switching performance control flag is ON, the switching performance control is performed as shown in Figure 8, and when either the second release condition or the third release condition is met, the switching performance control flag changes from the ON state to the OFF state, and EV driving is permitted.

[0088] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this embodiment. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0089] The control method described in this embodiment can be implemented by executing a pre-prepared program (control program) on a computer. This control program is stored, for example, in a computer-readable storage medium (e.g., memory 22) and executed by being read from this storage medium. This control program may also be provided in the form of a non-volatile (non-transient) storage medium such as flash memory, or it may be provided via a network such as the Internet.

[0090] Furthermore, in this embodiment, the computer that executes the control program is designated as the control device 20, and the processor 21 of the control device 20 executes the control program to realize the aforementioned control method, but this is not limited to this. The computer that executes the control program is not limited to one included in the vehicle 10, but may, for example, be included in a server device that can communicate with the vehicle 10 (control device 20).

[0091] This specification contains at least the following information. The components and other elements corresponding to those in the embodiments described above are shown in parentheses as examples, but are not limited thereto.

[0092] (1) A vehicle (vehicle 10) comprising: an engine (engine ENG); a second electric motor (second motor generator MG2) mechanically connected to the engine; a first electric motor (first motor generator MG1) mechanically connected to a drive wheel; a battery (battery BAT) capable of outputting power used to drive the first electric motor; and a control device (control device 20) capable of controlling the engine, the battery, the first electric motor, and the second electric motor, wherein the control device has a virtual stepped gear mode that controls the engine speed to a speed determined by a preset virtual gear line and vehicle speed according to the gear stage while the vehicle is moving, and / or controls the driving force of the first electric motor according to the gear stage and vehicle speed while the vehicle is moving, and the virtual stepped gear mode has A vehicle comprising: a first driving mode (series driving mode) in which the engine is operated at the aforementioned rotational speed and the power generated by the second electric motor is supplied to the first electric motor, and power is output from the first electric motor to the drive wheels; and a second driving mode (EV driving mode) in which the engine is stopped and power from the battery is supplied to the first electric motor, and power is output from the first electric motor to the drive wheels, wherein the control device performs the first driving mode when it switches to the virtual stepped gear mode and restricts the transition from the first driving mode to the second driving mode based on gear-shift-related information related to the gear shift.

[0093] According to (1), when switching to the virtual stepped transmission mode, the transition to the second driving mode, which puts the engine in a stopped state, can be restricted, thereby preventing the engine from starting and stopping repeatedly. Furthermore, by restricting the transition to the second driving mode based on gear-related information related to the gear, the transition to the second driving mode can be restricted in response to changes in the vehicle's driving state.

[0094] In other words, if the accelerator pedal is not pressed deeply enough after switching to the virtual stepped-gear mode, the vehicle enters the second driving mode. If the accelerator pedal is pressed immediately afterward and the vehicle switches back to the first driving mode, the engine speed will increase rapidly, resulting in excessive control (operation busy). Therefore, when switching to the virtual stepped-gear mode, the second driving mode is prohibited based on gear-related information to prevent excessive control and suppress excessive increases or decreases in engine speed after the switch.

[0095] (2) A vehicle as described in (1), wherein the control device includes a normal shift map in which normal shift lines corresponding to the shift steps are set, and sets a switching effect gear step, which is a gear step lower than the normal shift gear step set in the normal shift map, as the initial shift step when switching to the virtual stepped shift mode.

[0096] According to (2), when the virtual stepped gear mode is activated, the gear is set to a lower gear than the normal gear, which increases the engine speed and allows for a performance-enhancing effect.

[0097] (3) A vehicle as described in (2), wherein the initial gear shift is a gear shift set based on a performance gear shift map in which the gear shift performance is set to a lower gear than the normal gear shift set in the normal gear shift map.

[0098] According to (3), control can be made easier by using a performance speed change map.

[0099] (4) A vehicle as described in (2), wherein the initial gear shift is the lowest gear shift among the normal gear shifts set in the normal gear shift map that can be selected according to the vehicle speed.

[0100] According to (4), the gear shifting effect can be set using the normal shift map.

[0101] (5) A vehicle as described in (2), wherein the control device, after switching to the virtual stepped gear mode, permits a transition to the second driving mode when the normal gear position becomes equal to or greater than the switching effect gear position and the engine speed is greater than or equal to a predetermined value.

[0102] According to (5), when the engine speed exceeds a predetermined value and the gear ratio becomes the same as the normal gear ratio, it is determined that the vehicle is in a state that can be considered equivalent to normal driving, and the transition to the second driving mode is permitted.

[0103] (6) A vehicle as described in (2), wherein the control device, after switching to the virtual stepped gear mode, obtains a downshift request and permits a transition to the second driving mode if the normal gear position falls below the switching indicator gear position.

[0104] According to (6), when a downshift is requested, the demand for acceleration is high and the engine speed increases, so there is no need for any effects that enhance driving performance.

[0105] (7) A vehicle as described in (1), wherein the control device, after switching to the virtual stepped gear mode, permits the transition to the second driving mode after the first period has elapsed if no determination is made to permit the transition to the second driving mode during the first period.

[0106] According to (7), if no gear changes are made when the vehicle is stopped or in reverse, the virtual stepped gear mode will continue. Therefore, by allowing a transition to the second driving mode after a certain amount of time has passed, it is possible to suppress the continued use of the engine when the vehicle is stopped, etc.

[0107] (8) A vehicle as described in (7), wherein the control device performs upshift prohibition control in the virtual stepped gear mode, prohibiting upshifts if an upshift is requested again during the second period after a gear change, and permits a transition to the second driving mode if, after switching to the virtual stepped gear mode, no determination is made in the first period permitting a transition to the second driving mode, and the second period after a gear change has elapsed.

[0108] According to (8), prohibiting consecutive upshifts in a short period of time can suppress the occurrence of excessive control (shift busy). In addition, if the second driving mode is permitted while upshifts are prohibited, it is possible to avoid the engine being driven again during an upshift after the upshift prohibition ends.

[0109] (9) A vehicle as described in (3), wherein the control device acquires accelerator opening information, and when a switch to the virtual stepped shift mode is requested when the accelerator opening information is less than a predetermined value, sets the shift step that is set based on the performance shift map to the initial shift step.

[0110] According to (9), by changing the initial gear position according to the accelerator opening information, it is possible to set an appropriate gear position according to the vehicle's driving conditions. In addition, by making upshifts less likely to occur when the accelerator opening information is small compared to normal, it is possible to suppress any discomfort or incongruity in the user's driving feel.

[0111] (10) A vehicle as described in (9), wherein the control device acquires gradient information and varies the performance shift line in the performance shift map based on the gradient information.

[0112] According to (10), when the downhill gradient is steep, selecting a lower gear can help suppress any discomfort or incongruity in the user's riding experience.

[0113] (11) A vehicle as described in (4), wherein the control device acquires accelerator opening information, and when a switch to the virtual stepped transmission mode is requested when the accelerator opening information is greater than or equal to a predetermined value, sets the lowest-speed gear from the normal transmission gears set in the normal transmission map, which can be selected according to the vehicle speed, as the initial transmission gear.

[0114] According to (11), by changing the initial gear position according to the accelerator opening information, an appropriate gear position can be set according to the vehicle's driving conditions. In addition, by performing upshifts in stages as the vehicle speed increases when the accelerator opening information is large, a sense of exhilaration can be created for the user.

[0115] 10 Vehicle 20 Control device BAT Battery DW Drive wheels ENG Engine MG1 First motor generator (first electric motor) MG2 Second motor generator (second electric motor)

Claims

1. A vehicle comprising: an engine; a second electric motor mechanically connected to the engine; a first electric motor mechanically connected to a drive wheel; a battery capable of outputting power used to drive the first electric motor; and a control device capable of controlling the engine, the battery, the first electric motor, and the second electric motor, wherein the control device has a virtual stepped gear mode that controls the engine speed during movement by the braking force of the first electric motor to a speed determined by a preset virtual gear line and vehicle speed according to the gear stage, and / or controls the driving force of the first electric motor during movement by the braking force of the first electric motor based on a preset driving force line and vehicle speed according to the gear stage, and the virtual stepped gear mode has a first driving mode that operates the engine at the speed and supplies power generated by the second electric motor to the first electric motor, and outputs power from the first electric motor to the drive wheel, A vehicle comprising: a second driving mode in which the engine is stopped and power from the battery is supplied to the first electric motor, and power is output from the first electric motor to the drive wheels, wherein the control device performs the first driving mode when it switches to the virtual stepped gear mode, and restricts the transition from the first driving mode to the second driving mode based on gear-shift-related information related to the gear shift.

2. A vehicle according to claim 1, wherein the control device includes a normal shift map in which normal shift lines corresponding to the shift steps are set, and sets a switching effect gear step, which is a gear step lower than the normal shift gear step set in the normal shift map, as the initial shift step when switching to the virtual stepped shift mode.

3. A vehicle according to claim 2, wherein the initial gear shift is a gear shift set based on a performance gear shift map in which the gear shift performance gear is set to a lower gear than the normal gear shift gear set in the normal gear shift map.

4. A vehicle according to claim 2, wherein the initial gear shift is the lowest gear shift among the normal gear shifts set in the normal gear shift map that can be selected according to the vehicle speed.

5. A vehicle according to claim 2, wherein the control device, after switching to the virtual stepped gear mode, permits a transition to the second driving mode when the normal gear position becomes equal to or greater than the switching effect gear position and the engine speed is greater than or equal to a predetermined value.

6. A vehicle according to claim 2, wherein the control device, after switching to the virtual stepped gear mode, obtains a downshift request and permits a transition to the second driving mode if the normal gear position falls below the switching indicator gear position.

7. A vehicle according to claim 1, wherein the control device, after switching to the virtual stepped gear mode, permits the transition to the second driving mode after the first period has elapsed if no determination is made to permit the transition to the second driving mode during the first period.

8. A vehicle according to claim 7, wherein the control device performs upshift prohibition control to prohibit upshifting if an upshift is requested again during the second period after a gear change in the virtual stepped gear mode, and permits the transition to the second driving mode if, after switching to the virtual stepped gear mode, no determination is made to permit the transition to the second driving mode during the first period, and the second period after the gear change has elapsed.

9. A vehicle according to claim 3, wherein the control device acquires accelerator opening information, and when a switch to the virtual stepped shift mode is requested when the accelerator opening information is less than a predetermined value, sets the shift step set based on the performance shift map to the initial shift step.

10. A vehicle according to claim 9, wherein the control device acquires gradient information and varies the performance shift line in the performance shift map based on the gradient information.

11. A vehicle according to claim 4, wherein the control device acquires accelerator opening information, and when a switch to the virtual stepped transmission mode is requested when the accelerator opening information is greater than or equal to a predetermined value, sets the lowest-speed gear among the normal transmission gears set in the normal transmission map, which can be selected according to the vehicle speed, as the initial transmission gear.

Images